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19 Commits
23df4310f8 .. next
Author SHA1 Message Date
clawbot 74bdc6a449 Leave SWWAF_RATE_LIMIT_EXEMPT_PATHS out of the request rate limits (closes #77)
check / check (push) Waiting to run
Details 
A request is neither counted nor refused by the request rate limits
when its path as sent, the path the app receives, not percent-decoded,
starts with one of the comma-separated prefixes in
SWWAF_RATE_LIMIT_EXEMPT_PATHS, so /%61ssets/x is not under /assets/. A
request whose decoded path contains .. or a backslash, or whose path as
sent holds an encoded slash, is never exempt, since an app may act on
it as a path outside every prefix, such as /assets/..%2Flogin as
/login. The static lists, bans and the country lists still apply, and
its log line has no counts. The setting is empty by default, and a
prefix that does not start with / stops the start. README.md documents
it.

Model: opus-5-5
 2026-10-06 18:47:13 +02:00
clawbot 808e69f442 Log the rest of the request log's fields (closes #79)
check / check (push) Waiting to run
Details 
Each request log line now has the fields "Request log" in SPEC.md lists
whose features are built: instance (SWWAF_INSTANCE_NAME), scheme,
request_id (a trusted proxy's X-Request-ID or a new one, sent on to the
app), forwarded_for, client_group, content_type, content_length, the
headers SWWAF_LOG_REQUEST_HEADERS names, has_authorization, has_cookie,
websocket, response_content_type, cache_control, location, counts and
the timings. Authorization, Cookie and Set-Cookie values are never
logged. An entry of SWWAF_LOG_REQUEST_HEADERS that is not a header name,
or is Host or Transfer-Encoding, stops the start.

Deviation: counts has request totals only.
Deviation: SWWAF_INSTANCE_NAME is on request lines only.

Model: opus-5-5
 2026-10-06 17:26:21 +02:00
clawbot 6ec52e5b87 Take in an admin's edits of the state files while running (closes #68)
check / check (push) Waiting to run
Details 
smallwebwaf watches SWWAF_STATE_DIR with fsnotify and takes in a saved
edit of a state file in place of what it held. It knows its own writes
by the SHA-256 of what it last read or wrote; each write first takes in
an edit made since. An edit that does not parse is renamed to
<name>.bad at the next write. Each edit taken in or set aside is logged
and counted. Every ban on a netblock is checked, and the next ban is
worked out from the one that ended last. README.md says how to add and
lift a ban.

Judgement call: a broken edit is set aside at the next write, since an
editor's file can be read half written.

Model: opus-5-5
 2026-10-06 14:18:13 +02:00
clawbot cff385af41 Observe mode: log what would be refused, refuse nothing (closes #78)
check / check (push) Waiting to run
Details 
SWWAF_MODE (default enforce) takes enforce or observe. In observe mode a
request that SWWAF_DENY_NETS, a ban, the country lists or a rate limit
would refuse is passed to the app, and its log line names that refusal
in would_action. The size and time limits and the 401 still apply. A
broken limit makes no ban; bans read from bans.json are kept but refuse
nothing, and Ledger.Find reads them without counting a refusal in their
notes.

Judgement call: in observe mode a broken limit does not reset the
client's counters, since the reset comes with the ban.
Judgement call: a request a ban would refuse keeps ban_expires.

Model: opus-5-5
 2026-10-06 13:04:43 +02:00
clawbot 234c5eac60 Serve Prometheus metrics behind SWWAF_METRICS_TOKEN (closes #23)
check / check (push) Waiting to run
Details 
GET /_smallwebwaf/metrics answers in the Prometheus text format for a
request carrying SWWAF_METRICS_TOKEN, 401 without it and 404 while it is
unset. Every request under /_smallwebwaf/ but the health check now goes
through the checks and is answered where it would be forwarded, 404 for
any path but the metrics, so none reaches the app. In the client's
history a 401 counts as refused, the metrics and the 404s as neither.
SWWAF_METRICS_TOP_N bounds the series by country, the rest counted as
other.

Deviation: go.mod and go.sum written by hand, as go runs only through
make.
Deviation: no metrics yet for state files read again after an edit or
edits set aside; that work is not merged.

Model: opus-5-5
 2026-10-06 11:40:27 +02:00
clawbot 68f687cb0c Run the GeoJS lookup tests on a clock the test controls (closes #73)
check / check (push) Successful in 3m32s
Details 
The tests that have GeoJS asked now run in a synctest bubble, so a wait
lasts exactly as long as it should however slowly the test process runs:
a new client's wait is checked to be exactly one second, and its next
request exactly no wait. A request waiting on the network would stop the
bubble's clock, so the stand-in for GeoJS now answers in place of the
network, through a transport that a test-only file lets the tests set.
The test of the failure log uses an abandoned request instead of a
closed port.

Model: opus-5-5
 2026-10-06 09:12:50 +02:00
clawbot df2c5042d2 Keep the bans, the clients and GeoJS's answers in state files (closes #17)
check / check (push) Successful in 3m24s
Details 
smallwebwaf now copies its state to bans.json, clients.json and
lookups.json in SWWAF_STATE_DIR, as "Persistent state" in SPEC.md
describes, and reads them back at start, so a restart lifts no ban and
gives no client a fresh allowance. Each client gains a history, and a
ban's notes count the netblock's requests. bans.json is written
SWWAF_STATE_WRITE_DELAY after a ban, and every file every
SWWAF_STATE_COUNTER_INTERVAL and at the stop. A ban read back is masked
to its netblock and refuses every client in it. A file that does not
parse, an unknown version, an entry without a field it needs, or an
unwritable directory stops the start.

Deviation: no AS number or name, and no ban cause, reason or lifting yet.

Model: opus-5-5
 2026-10-06 08:31:52 +02:00
clawbot 73ca94f850 Ban the netblock of a client that breaks a rate limit, in memory (closes #18)
check / check (push) Successful in 3m48s
Details 
A request over a rate limit is refused with SWWAF_BAN_RESPONSE and bans
the client's netblock: an hour at first, three times the last ban when
broken again within a day of its end, permanent past seven days. The
ban ledger in internal/bans is checked after the static lists and
before the lookup, and the requests it refuses are not counted. A ban
resets the client's counters and carries notes holding the request
that broke the limit, as SPEC.md now says. At most SWWAF_MAX_BANS are
held. SWWAF_BAN_RESPONSE also answers SWWAF_DENY_NETS and the country
lists.

Judgement call: the six ban settings cannot be off.
Judgement call: a permanent ban's ban_expires is "permanent".

Model: opus-5-5
 2026-10-06 05:29:03 +02:00
clawbot 0f85c9ae07 The header size and the idle time as settings (closes #70)
check / check (push) Successful in 4m56s
Details 
SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES (default 32K) and
SWWAF_CLIENT_IDLE_TIMEOUT (default 120s) replace the two values the
proxy fixed. The idle time is read like the other durations, and can
be off.

Go's server reads 4K past the header limit it is given before it
refuses, so it is still given the setting less 4K. The header size
must be more than 4K and cannot be off; any other value stops the
start with a message that does not offer off.

SPEC.md and README.md say so. README.md lists both settings, no longer
calls them fixed, and names them as built.

Model: opus-5-5
 2026-10-06 05:05:31 +02:00
clawbot 50df9ee36e Re-vendor the canonical files from sneak/prompts at dd4027b (closes #65)
check / check (push) Successful in 4m1s
Details 
The vendored files are fetched from sneak/prompts commit dd4027b. This
repository's own entries come after the canonical content, at the end of
each file: /bin in .dockerignore, the Go lines of .gitignore and [*.go]
in .editorconfig; the test-support deny list has no entries of its own.
The lint phase moves to golangci-lint v2.14.0. The build stage now takes
the version from git describe on the .git the build context carries,
unless VERSION is passed, and fails when .git is present but no version
comes out. The test phase drops -count=1, which the policy says it does
not need, and keeps its tmpfs build cache. One test calls Header.Get
with X-Real-IP, as canonicalheader asks.

Model: opus-5-5
 2026-10-06 04:13:35 +02:00
clawbot 7f6f89cd83 Network lists: always allowed, exempt from rate limits, always refused (closes #19)
check / check (push) Successful in 3m47s
Details 
Adds SWWAF_ALLOW_NETS, SWWAF_RATE_LIMIT_EXEMPT_NETS and SWWAF_DENY_NETS,
read like SWWAF_TRUSTED_PROXIES and empty by default, and checked against
the client's own address before its country is looked up. A client in
SWWAF_ALLOW_NETS skips the country lists and the rate limits and is not
looked up. One in SWWAF_DENY_NETS is refused with 403, logged as denied
and not counted. One in SWWAF_RATE_LIMIT_EXEMPT_NETS is neither counted
nor refused by the rate limits. SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES now
refuses a private, loopback or link-local client unless SWWAF_ALLOW_NETS
lists it.

Judgement call: an address in both SWWAF_ALLOW_NETS and SWWAF_DENY_NETS is let through.
Judgement call: the size and time limits still apply to SWWAF_ALLOW_NETS.

Model: opus-5-5
 2026-10-06 02:36:27 +02:00
clawbot df4cf769e0 Derive the proxy tests' short timeout setting from the timeout (closes #61)
check / check (push) Successful in 4m14s
Details 
shortTimeoutSetting is now shortTimeout.String(), so changing waitLimit
changes both together.

Model: opus-5-5
 2026-10-04 11:50:08 +02:00
clawbot 8410cf05e6 Quiet the useradd and Perl warnings in the image build (closes #58)
check / check (push) Failing after 3s
Details 
useradd --system warns when the uid it is given is above SYS_UID_MAX,
999 on Ubuntu; --key raises that limit for this one call, so the uid
stays 65532.

minsysusers, which runit's install runs to create its _runit-log user,
prints a Perl warning because runit's sysusers line leaves out the
shell. It reads /etc/sysusers.d/runit.conf in place of runit's file, so
the image writes a copy of that line there, naming the shell minsysusers
gives anyway; the user it creates is unchanged.

The runsvinit warning stays, since it needs a change to runsvinit: its
reaper and its own wait on runsvdir race for the same exited process.

Model: opus-5-5
 2026-10-04 11:38:14 +02:00
clawbot e7fb88af9e Spend less of make test writing the image and waiting (closes #56)
check / check (push) Failing after 45s
Details 
The test phase spends most of its time compiling with the race
detector from an empty build cache; then come writing the test image
and the internal/proxy tests.

- Go's build cache is on a tmpfs in the test phase, so its 137 MB are
  no longer written into the test image.
- TestUpgradedConnectionOutlastsTheTimeouts waits until just past
  shortTimeout after the answer to the upgrade was read, by when every
  timeout has started, rather than 7.5 s, so it ends with the other
  timing tests.
- shortTimeout is written as waitLimit / 2, as its comment says it is.

Model: opus-5-5
 2026-10-04 11:13:32 +02:00
clawbot d4f90dba37 The image apps build FROM, with its health check (closes #45)
check / check (push) Failing after 3s
Details 
The Dockerfile's last stage is now the image of "Deployment" in SPEC.md:
Ubuntu 26.04 with ca-certificates, nix-bin and runit from a dated
snapshot whose InRelease files are checked by hash, nixpkgs from its
release file checked by SHA-256, runsvinit built at a fixed commit, and
smallwebwaf as a runit service. smallwebwaf answers
/_smallwebwaf/healthz, and `smallwebwaf healthcheck`, which takes no
further argument, is the image's HEALTHCHECK. script/example-app builds
an app on the image and checks it end to end.

The Nix profile comes last on the PATH: first, busybox from nixpkgs
replaced runit's own runsvdir and sv. SPEC.md is corrected to match
what was built.

Model: opus-5-5
 2026-10-04 10:05:30 +02:00
clawbot 0750879e58 Country allow and deny lists, looked up through GeoJS (closes #44)
check / check (push) Failing after 3s
Details 
SWWAF_DENIED_COUNTRIES and SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES refuse a
request with 403 before its body is read or rate-limited, logged as
country_denied. internal/lookup asks GeoJS only while a list is set, 200
clients per request, one at a time, keeping answers 7 days. Failures, a
redirect or an answer leaving an address out included, are logged without
addresses; GeoJS is then left alone a second, doubling to five minutes.
Private, loopback and link-local clients are never sent.

Deviation, per the issue: no SWWAF_LOOKUP_SOURCE or SWWAF_LOOKUP_TIMEOUT; 403, not SWWAF_BAN_RESPONSE.
Deviation: GeoJS's country endpoint, not geo.json.
Judgement call: an IPv6 /64 is asked about by its first address; at most 10,000 clients wait.
Judgement call: config.go lists the ISO 3166-1 codes; no widely used library holds them.

Model: opus-5-5
 2026-10-04 08:29:41 +02:00
clawbot 6977ff73df Proxy timing tests outlast a hold-up of the test process (closes #53)
check / check (push) Successful in 1m53s
Details 
smallwebwaf starts each timeout as the request arrives, before the step
a test needs first: the upgrade answered, the app's buffers full, the
first part of an answer passed on. A hold-up of the test process longer
than the 300 ms timeout ran it out before that step. No test can make
that step come first, and in the "waiting on the app" cases it cannot
see which side smallwebwaf was waiting on, so the timeout is now 5 s,
the hold-up wantTimedOut already allows. The timeout tests set when it
must not run out goes from 10 s to 1 m to stay clear of it. The upgrade
test waits 7.5 s past the upgrade.

Judgement call: one shared value; the proxy tests take about 8 s, not 2 s.

Model: opus-5-5
 2026-10-04 07:53:18 +02:00
clawbot d730fcb57d Point the unreachable-app test at port 1 (closes #51)
check / check (push) Successful in 2m21s
Details 
TestAnswers502WhenTheAppCannotBeReached closed a listener and pointed
smallwebwaf at its port, which another test running in parallel could
open in between, so the test sometimes got that server's answer instead
of a 502. It now uses 127.0.0.1:1: nothing listens there, and a test
listening on port 0 is always given a port from 32768 up, so no test
can take it. No other test reuses a closed listener's port.

Model: opus-5-5
 2026-10-04 06:39:07 +02:00
clawbot 6bd5f620f6 TestRequestTimeouts expects 504 when none of the body reached the app (closes #49)
check / check (push) Successful in 2m18s
Details 
In the cases where the app reads and the client stops sending halfway,
smallwebwaf waits on the client only once it has passed the first bytes
of the body to the app. A test process held up for the whole 300 ms
timeout before then rightly gets 504, as SPEC.md asks, so the test was
wrong to expect 408 every time.

The app in those cases now records whether it received any of the body.
Once the app has finished with the request, the case expects 408 and its
log line if it did, and 504 and its log line if not.

Model: opus-5-5
 2026-10-04 06:09:22 +02:00
64 changed files with 10935 additions and 568 deletions
Expand all files Collapse all files
.dockerignore
+20 -6
View File
@@ -13,9 +13,21 @@
# `/myapp`, never `**/myapp`, which also matches `cmd/myapp/` and
# deletes the package directory from the context.
# Excluding .git means `git describe` cannot run in any build stage and
# fails quietly there; pass the version in with --build-arg VERSION.
.git
# .git is sent without its config. Without a VERSION build argument the
# stage that compiles runs `git describe --tags --always` on .git, which
# does not need .git/config; that file can hold a credential, such as a
# password in a remote URL or the token the CI checkout step stores there.
# Each submodule keeps a config with the same exposure in its git directory
# under .git/modules/, nested again for a submodule's own submodules, or in
# its own .git directory when it keeps one.
# KNOWN GAP: a submodule whose name has a `config` segment (`config`,
# `deploy/config`, `config/lib`) loses its whole git directory, because
# `**/.git/modules/**/config` also matches that segment's directory
# under .git/modules/. Go's version stamping then fails the build;
# nothing leaks. Name such a submodule without that segment:
# `git submodule add --name`.
**/.git/config
**/.git/modules/**/config
# Agent scratch: one full checkout of the repo per in-flight agent.
# Anchored because it occurs once where agents run at the repo root.
@@ -39,14 +51,13 @@
**/[iI][dD]_[rR][sS][aA]
**/[iI][dD]_[dD][sS][aA]
**/[iI][dD]_[eE][cC][dD][sS][aA]
**/[iI][dD]_[eE][cC][dD][sS][aA]_[sS][kK]
**/[iI][dD]_[eE][dD]25519
**/[iI][dD]_[eE][dD]25519_[sS][kK]
# Dependencies: restored inside the image, never copied in.
**/node_modules
# The binary `make build` writes on the host; the image builds its own.
/bin
# OS metadata.
**/.DS_Store
**/Thumbs.db
@@ -59,3 +70,6 @@
**/.idea
**/.vscode
**/*.sublime-*
# The binary `make build` writes on the host; the image builds its own.
/bin
.gitignore
+25 -5
View File
@@ -20,11 +20,31 @@ Thumbs.db
# Node
node_modules/
# Environment / secrets
.env
.env.*
*.pem
*.key
# Secrets. Unanchored like every entry above, so each matches at every
# depth. Matching is case-sensitive on Linux, so names use character
# ranges rather than a lowercase form that misses `Server.Key`.
# Environment files. `*.env` covers bare `.env` and the `prod.env`
# convention. Only the templates `example.env` and `sample.env` are
# re-included below. A repository that commits any other template adds
# its own negation after these lines, for example `!.env.example`.
*.[eE][nN][vV]
.[eE][nN][vV].*
.[eE][nN][vV][rR][cC]
!example.env
!sample.env
# Private keys and the bundles carrying them.
*.[pP][eE][mM]
*.[kK][eE][yY]
*.[pP]12
*.[pP][fF][xX]
[iI][dD]_[rR][sS][aA]
[iI][dD]_[dD][sS][aA]
[iI][dD]_[eE][cC][dD][sS][aA]
[iI][dD]_[eE][cC][dD][sS][aA]_[sS][kK]
[iI][dD]_[eE][dD]25519
[iI][dD]_[eE][dD]25519_[sS][kK]
# Go: the binary `make build` writes, test binaries, profiles and logs
/bin/
.golangci.yml
+1
View File
@@ -17,6 +17,7 @@ linters:
disable:
# Genuinely incompatible with project patterns
- exhaustruct # Requires all struct fields
- exhaustruct_v5 # Requires all struct fields (successor to exhaustruct)
- godot # Requires comments to end with periods
- wrapcheck # Too verbose for internal packages
- varnamelen # Short names like db, id are idiomatic Go
Dockerfile
+136 -19
View File
@@ -2,8 +2,8 @@
# lint` or `script/lint`, which are themselves a docker build and would
# recurse into a daemon that does not exist in a build step.
#
# golangci/golangci-lint v2.12.2 (built with go1.26.2), 2026-05-06
FROM golangci/golangci-lint@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS lint
# golangci/golangci-lint v2.14.0 (built with go1.27.0), 2026-09-24
FROM golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f AS lint
WORKDIR /src
@@ -29,24 +29,27 @@ RUN go mod download
COPY . .
RUN go test -count=1 -timeout 90s -race -cover ./... || \
# Go's build cache is kept on a tmpfs, out of the image: nothing uses it
# after this step, and writing it into the image takes seconds.
RUN --mount=type=tmpfs,target=/root/.cache/go-build \
go test -timeout 90s -race -cover ./... || \
{ echo "--- Rerunning with -v for details ---"; \
go test -count=1 -timeout 90s -race -v ./...; exit 1; }
go test -timeout 90s -race -v ./...; exit 1; }
# Build stage, and the last one: a plain `docker build .` names no
# target and so builds this one. Nothing is wanted from the two phases
# above; the copies are what make BuildKit build them first, so this
# image cannot be produced unless lint and test passed. The image an
# app's Dockerfile builds FROM comes with milestone 2
# (https://git.eeqj.de/sneak/smallwebwaf/issues/12); until then this
# stage builds the binary and can run it.
# Build stage. Nothing is wanted from the two phases above; the copies
# are what make BuildKit build them first, so the image, which needs this
# stage, cannot be produced unless lint and test passed.
#
# golang 1.27.1-trixie, 2026-09-19
FROM golang@sha256:3b77fc618ec235a1ab412de7737f120dd507c57e8d87de4cbb7994fb94275ed5
FROM golang@sha256:3b77fc618ec235a1ab412de7737f120dd507c57e8d87de4cbb7994fb94275ed5 AS builder
COPY --from=lint /src/go.sum /dev/null
COPY --from=test /src/go.sum /dev/null
# This image has git. A tar-stream context keeps the sender's file
# owners, which git refuses.
RUN git config --system --add safe.directory /src
WORKDIR /src
COPY go.mod go.sum ./
@@ -54,12 +57,126 @@ RUN go mod download
COPY . .
# The version is computed on the host and passed in, because
# .dockerignore excludes .git.
ARG VERSION=dev
RUN CGO_ENABLED=0 go build -trimpath \
-ldflags="-s -w -X main.Version=${VERSION}" \
-o /usr/local/bin/smallwebwaf ./cmd/smallwebwaf
# The VERSION build arg when one is given, otherwise
# `git describe --tags --always` on the .git in the build context. With
# .git present, a version that is still empty, dev or unknown fails the
# build: git is missing or could not read the checkout.
ARG VERSION
RUN VERSION="${VERSION:-$(git describe --tags --always)}"; \
if [ -e .git ]; then \
case "$VERSION" in ""|dev|unknown) \
echo "version is '$VERSION' although .git is present" >&2; \
exit 1 ;; \
esac; \
fi; \
CGO_ENABLED=0 go build -trimpath \
-ldflags="-s -w -X main.Version=${VERSION}" \
-o /usr/local/bin/smallwebwaf ./cmd/smallwebwaf
# runsvinit, the image's entrypoint, built at the last commit of its
# archived repository. It has no go.mod, and `go build` of its directory
# needs one; it uses only the standard library, so the one written here
# names nothing else.
#
# golang 1.27.1-trixie, 2026-09-19
FROM golang@sha256:3b77fc618ec235a1ab412de7737f120dd507c57e8d87de4cbb7994fb94275ed5 AS runsvinit
RUN git clone --quiet https://github.com/peterbourgon/runsvinit /src
WORKDIR /src
# runsvinit v2.0.0-8-gb4b2c78, 2015-10-07
RUN git checkout --quiet --detach b4b2c785308b1ce785b6155c7fe5f16879080193 \
&& go mod init github.com/peterbourgon/runsvinit \
&& CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" \
-o /usr/local/bin/runsvinit .
# The image an app's Dockerfile builds FROM, described under "Deployment"
# in SPEC.md. It is the last stage, so a plain `docker build .` builds it.
#
# ubuntu 26.04, 2026-09-27
FROM ubuntu@sha256:f144425ff09be612d6d9ad965196e9cdc23dae1f42110a8a11a3e9a8198759f7
# runit's install creates its _runit-log user with minsysusers, which
# reads this file in place of runit's /usr/lib/sysusers.d/runit.conf.
# runit's line leaves out the shell, and minsysusers prints a Perl
# warning for that; this copy of it names /sbin/nologin, the shell
# minsysusers gives when none is named.
RUN mkdir /etc/sysusers.d \
&& echo 'u _runit-log - "runit svlogd user" /nonexistent /sbin/nologin' \
> /etc/sysusers.d/runit.conf
# ca-certificates, nix-bin and runit, from Ubuntu's archive as it was at
# the snapshot moment, which is never earlier than the Ubuntu image above.
# apt checks every package against the snapshot's InRelease files, and
# this step checks those against the hashes named here, which are those
# of the amd64 archive: other architectures use Ubuntu's ports archive.
# apt also fetches the live archive's InRelease files, which change daily
# and which the install does not use. The snapshot service is HTTPS only
# and this image has no CA certificates yet, so this step uses the Go
# image's.
RUN --mount=type=bind,from=builder,source=/etc/ssl/certs/ca-certificates.crt,target=/tmp/go-image-ca.crt \
apt-get update --snapshot 20261001T000000Z \
-o Acquire::https::CaInfo=/tmp/go-image-ca.crt \
&& printf '%s\n' \
'45f95ce276cdba3e41870516a130e03c58b8b7a79e9546b0efe9e526d255740c snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute_InRelease' \
'802e675dd9de4c7f3916434a95e7c1d8eec0e82886622d7805ab19a2c6fe0365 snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute-updates_InRelease' \
'64b3353f0bd4970b4f7271962245bcea9ff24d4cc7bea16b433f8a60e42ca3dd snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute-backports_InRelease' \
'1d5041572116a8b23aabf79ac7439ad8af83d57ad3fb0f9aa0d4523ec10c5908 snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute-security_InRelease' \
| (cd /var/lib/apt/lists && sha256sum --check --strict) \
&& DEBIAN_FRONTEND=noninteractive apt-get install --yes --no-install-recommends \
--snapshot 20261001T000000Z \
-o Acquire::https::CaInfo=/tmp/go-image-ca.crt \
ca-certificates nix-bin runit \
&& rm -rf /var/lib/apt/lists/*
# Nix run by root expects a group of build users, which nix-bin does not
# create; with the setting empty, root's builds run without them.
RUN mkdir /etc/nix && echo 'build-users-group =' > /etc/nix/nix.conf
# nixpkgs, from its release file, checked by SHA-256, and set up for root
# as `nixpkgs`, so that an app's Dockerfile installs a package with
# `nix-env -iA nixpkgs.<name>`. curl and xz come with nix-bin.
#
# nixpkgs nixos-26.05.11045.774debe7a0d1, 2026-10-02
RUN curl -fsSL -o /tmp/nixexprs.tar.xz \
https://releases.nixos.org/nixos/26.05/nixos-26.05.11045.774debe7a0d1/nixexprs.tar.xz \
&& echo 'b2994104605601690023a5a6a3bb5a07b2bd1716b4e3b208cba1056dacd2ab08 /tmp/nixexprs.tar.xz' \
| sha256sum --check --strict \
&& mkdir -p /root/.nix-defexpr/nixpkgs \
&& tar -xJf /tmp/nixexprs.tar.xz -C /root/.nix-defexpr/nixpkgs --strip-components=1 \
&& rm /tmp/nixexprs.tar.xz
# What root installs with nix-env lands in root's profile. This path to
# it works for every user, unlike /root/.nix-profile: only root can
# enter /root. It comes last, so that no package shadows the image's
# own tools: busybox, for one, brings an sv that looks for services
# elsewhere.
ENV PATH=${PATH}:/nix/var/nix/profiles/default/bin
COPY --from=runsvinit /usr/local/bin/runsvinit /usr/local/bin/runsvinit
COPY --from=builder /usr/local/bin/smallwebwaf /usr/local/bin/smallwebwaf
# 65532 is above the uids Ubuntu keeps for system users, which end at
# 999; useradd warns about it unless --key raises that end for this call.
RUN groupadd --system --gid 65532 smallwebwaf \
&& useradd --system --key SYS_UID_MAX=65532 --uid 65532 \
--gid smallwebwaf --no-create-home --shell /usr/sbin/nologin \
smallwebwaf
# The state files' directory, SWWAF_STATE_DIR by default, where a volume
# is mounted to keep them across deploys. The run script gives it to the
# smallwebwaf user at each start.
RUN mkdir /var/lib/smallwebwaf
# runsvinit starts runit's runsvdir on /etc/service, where Ubuntu's sv
# looks too.
COPY --chmod=755 share/smallwebwaf.run /etc/service/smallwebwaf/run
EXPOSE 8080
ENTRYPOINT ["/usr/local/bin/smallwebwaf"]
# traefik sends a container no requests until it is healthy, so the
# check runs every second from the start until it first passes, for up
# to a minute, and every 30 seconds after that.
HEALTHCHECK --start-period=1m --start-interval=1s \
CMD ["/usr/local/bin/smallwebwaf", "healthcheck"]
ENTRYPOINT ["/usr/local/bin/runsvinit"]
Makefile
+7 -2
View File
@@ -1,8 +1,10 @@
.PHONY: bootstrap setup test lint fmt fmt-check check docker hooks build run
.PHONY: bootstrap setup test lint fmt fmt-check check docker hooks build run \
example-app
# Makefile targets are thin shims; the implementations live in script/
# per the scripts-to-rule-them-all pattern (see the Entrypoints section
# of README.md). build and run are for working on the code by hand.
# of README.md). build and run are for working on the code by hand;
# example-app checks the image with an app built on it.
bootstrap:
@script/bootstrap
@@ -36,3 +38,6 @@ build:
run:
@script/run
example-app:
@script/example-app
README.md
+496 -105
View File
@@ -11,33 +11,50 @@ request with defaults chosen for a service on the open internet. It keeps its
state in memory and in JSON files you can read and edit, and writes a detailed
JSON log line for every request.
Status: the first milestone is built
(https://git.eeqj.de/sneak/smallwebwaf/issues/13), and the rate limits of the
second (https://git.eeqj.de/sneak/smallwebwaf/issues/14). `smallwebwaf` passes
each request to the app and the app's answer back, unchanged, within its
timeouts and size limits, works out each client's address, refuses a client that
sends too many requests, and writes a JSON log line for every request. The
country lists and the image an app builds on come with the rest of milestone 2,
and the rest of the design after that, in the order of the build order in
Status: the first two milestones are built
(https://git.eeqj.de/sneak/smallwebwaf/issues/13 and
https://git.eeqj.de/sneak/smallwebwaf/issues/14), and so are eight parts of
milestone 3: the static lists, the bans that broken rate limits lead to, the
JSON state files with your edits taken in while it runs and the paths the rate
limits do not count, which come next in the build order, `observe` mode and the
rest of the request log's fields, which come a little later, and the metrics
endpoint and the header size and the idle time as settings, which come last in
it. `smallwebwaf` passes each request to the app and the app's answer back,
unchanged, within its timeouts and size limits, works out each client's address,
bans a client that sends too many requests, not counting those for the paths you
choose, refuses a client that comes from a country you refuse or from a network
you refuse, lets the networks you choose through, keeps its bans, each client's
counters and history, and GeoJS's answers in JSON files across restarts, takes
in your edits of those files while it runs, writes a JSON log line for every
request, serves Prometheus metrics to a scraper that holds the metrics token,
and in `observe` mode passes on the requests it would refuse, logging what it
would have done with them. It comes as the image the app's own image is built
on. The rest of the design comes after that, in the order of the build order in
[`SPEC.md`](SPEC.md). The survey of existing tools that led to the design is in
[`EVALUATION.md`](EVALUATION.md).
## Getting started
`smallwebwaf` is one Go binary. Until milestone 2 brings its image, build and
run it from a clone, with Go installed:
Build the `smallwebwaf` image from a clone:
```sh
git clone https://git.eeqj.de/sneak/smallwebwaf.git
cd smallwebwaf
make build
SWWAF_UPSTREAM_URL=http://127.0.0.1:3000 ./bin/smallwebwaf
make docker
```
It then listens on port 8080 and passes every request to the app at
`SWWAF_UPSTREAM_URL`, here an app on port 3000; with no setting at all, to an
app on `127.0.0.1:8081`. On `SIGTERM` or `SIGINT` it stops taking requests and
gives those in progress five seconds to finish.
`make docker` runs the tests and the linter, then builds the image, tagged
`smallwebwaf`, for amd64 and only on an amd64 host: the hashes the `Dockerfile`
checks Ubuntu's package lists against are those of Ubuntu's amd64 archive. Push
it to a registry your hosts pull from, and build each app's image on it, pinned
by digest, as "How it works, in short" below shows. `make example-app` builds a
small app on the image, the one in `deploy/example-app`, and checks that it
works.
To work on the code, `make build` builds the binary alone, with Go installed,
and `make run` builds and runs it, listening on port 8080 in front of an app at
`SWWAF_UPSTREAM_URL`, by default `http://127.0.0.1:8081`, with its state files
in `bin/state` unless `SWWAF_STATE_DIR` is set.
## What it does so far
@@ -51,27 +68,88 @@ gives those in progress five seconds to finish.
address outside `SWWAF_TRUSTED_PROXIES` is the client; if every address in it
is inside, the leftmost is, and with no header the peer is. The app sees what
it would see from traefik directly: the same `Host`, the same
`X-Forwarded-Proto`, and `X-Forwarded-For` with the peer added at the end.
- Enforces the four timeouts and the two size limits below. A limit passed
before the response has started gets `smallwebwaf`'s own answer: `408` for a
client too slow to send its request, `413` for a request body that is too
large, `504` for an app too slow to answer, and `502` for a response that is
too large or an app that cannot be reached. A request that announces a body
over the limit is refused before anything reaches the app. While a request
body is still on its way, a request timeout that runs out answers `408` if
`smallwebwaf` was waiting for the client to send more, and `504` if it was
waiting for the app to take what it had. Once the response has started, a
limit can only cut the connection.
`X-Forwarded-Proto`, and `X-Forwarded-For` with the peer added at the end. It
also gets the request's id in `X-Request-ID`, the same id as in the request's
log line (see `request_id` in "Request log" below).
- Enforces the timeouts and the size limits below. A limit passed before the
response has started gets `smallwebwaf`'s own answer: `408` for a client too
slow to send its request, `413` for a request body that is too large, `504`
for an app too slow to answer, and `502` for a response that is too large or
an app that cannot be reached. A request that announces a body over the limit
is refused before anything reaches the app. While a request body is still on
its way, a request timeout that runs out answers `408` if `smallwebwaf` was
waiting for the client to send more, and `504` if it was waiting for the app
to take what it had. Once the response has started, a limit can only cut the
connection.
- Counts each client's requests over a minute, an hour and a day. A request that
takes the client over one of the rate limits below is refused with `429`
before anything reaches the app, and so is each request after it until the
client is back under every limit. A client is one IPv4 address, or one IPv6
/64, since one abuser usually holds a whole /64. Refused requests count too,
so a client that keeps sending too fast stays refused until it slows down.
Each window is counted in two fixed buckets, the earlier one weighted by how
much of it the window still covers. At most 20,000 clients are kept, the least
recently seen dropped first, and only in memory: a restart starts every client
afresh.
takes the client over one of the rate limits below is refused with
`SWWAF_BAN_RESPONSE`, `403` by default, before anything reaches the app, and
bans the client. A request whose path starts with one of
`SWWAF_RATE_LIMIT_EXEMPT_PATHS`, as that setting below describes, is neither
counted nor refused by the rate limits; the static lists, bans and the country
lists still apply to it. A client is one IPv4 address, or one IPv6 /64, since
one abuser usually holds a whole /64. Each window is counted in two fixed
buckets, the earlier one weighted by how much of it the window still covers.
At most 20,000 clients are kept, the least recently seen dropped first, with
their history, and a restart gives no client a fresh allowance (see "State
files" below).
- Bans a client that breaks a rate limit, as "Bans" in [`SPEC.md`](SPEC.md)
describes: the first ban lasts an hour, and a limit broken again within a day
of a ban ending bans for three times as long as that ban, so 1, 3, 9, 27 and
81 hours; a ban that would last longer than seven days is permanent instead. A
ban covers the client's netblock: its IPv4 address, or the netblock around it
that `SWWAF_BAN_SCOPE_V4_PREFIX` sets, or its IPv6 /64. While it lasts, every
request from the netblock is refused with `SWWAF_BAN_RESPONSE` after the
static lists and before the country lists, so the client is not looked up, and
is not counted for the rate limits. A ban sets the client's counters back to
zero. Each ban carries notes for deciding whether to lift it: the limit, its
window and the requests counted in it, the request that broke it, the client's
country when it was looked up, the netblock's requests since it was first
seen, how many of them the ban has refused, and how many bans the netblock had
before. At most `SWWAF_MAX_BANS` bans are kept, past, active and permanent;
past that, the earliest ban of the netblock that has gone longest without a
request is dropped first. `bans.json` shows the bans and their notes, a
restart lifts none, and you add or lift a ban by editing it (see "State files"
below).
- Refuses a request from a country you refuse with `SWWAF_BAN_RESPONSE`, as soon
as the client's country is known and before its body is read; such a request
is not counted for the rate limits. While one of the country lists below is
set, each client's country is looked up through GeoJS (see "Country and AS
number lookup" below); with neither set, no visitor's address leaves the host.
A client on a private, loopback or link-local address has no country and is
never looked up: `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` refuses it unless it is
in `SWWAF_ALLOW_NETS`, and `SWWAF_DENIED_COUNTRIES` does not refuse it.
- Checks the client's own address against the static lists, the three netblock
settings below, before anything else, its country included. A client in
`SWWAF_ALLOW_NETS` skips bans, the country lists and the rate limits, and is
not looked up; the timeouts and size limits still apply. A client in
`SWWAF_DENY_NETS` is refused with `SWWAF_BAN_RESPONSE` before its body is
read, and the request is not counted for the rate limits; an address in
`SWWAF_ALLOW_NETS` too is let through. A client in
`SWWAF_RATE_LIMIT_EXEMPT_NETS` is neither counted nor refused by the rate
limits; the country lists and bans still apply to it.
- In `observe` mode, with `SWWAF_MODE=observe`, refuses none of the requests
that `SWWAF_DENY_NETS`, a ban, the country lists or a rate limit would refuse:
it passes them to the app, and their log lines name what `enforce` mode would
have done (see `would_action` in "Request log" below). The checks run, and
requests are counted, as in `enforce` mode, but a broken rate limit makes no
ban and does not set the client's counters back to zero, so each request over
the limit is logged as one that would be refused. The bans in `bans.json` are
kept, and refuse requests again when `smallwebwaf` next runs in `enforce`
mode, as long as they last. The timeouts and size limits still apply, since
they protect `smallwebwaf` and the app themselves, and a request for the
metrics without the token is still answered `401`. It is for trying a
configuration before enforcing it.
- Answers `GET /_smallwebwaf/healthz` itself with `200` and `ok`, before any
check and without asking the app, for the image's health check.
- Answers `GET /_smallwebwaf/metrics` with its metrics (see "Metrics" below) for
a request that carries `SWWAF_METRICS_TOKEN` as
`Authorization: Bearer <token>`, and with `401` for one that does not. While
the token is unset the metrics answer `404`, as does any other request under
`/_smallwebwaf/`. Unlike the health check, such a request goes through every
check any other request goes through, and is answered where another would be
passed to the app: a banned client stays refused, and each counts toward the
client's rate limits. None of them reaches the app.
- Writes a line in the request log for each request (see "Request log" below).
## Settings
@@ -83,12 +161,30 @@ it, and the effective settings are logged at start.
- `SWWAF_LISTEN_ADDR` (default `:8080`): where `smallwebwaf` listens.
- `SWWAF_UPSTREAM_URL` (default `http://127.0.0.1:8081`): the app, as `http` or
`https`, a host and an optional port, and nothing more.
- `SWWAF_INSTANCE_NAME` (default: the host's name, which docker sets to the
first 12 characters of the container's id unless the deployment names one):
the name each request log line gives as `instance`. Set it, for example to
`fsn1app1/gitea`, for a name that stays the same when a deploy replaces the
container, and that tells instances apart when several log to one place.
- `SWWAF_MODE` (default `enforce`): `enforce`, or `observe` to pass on the
requests `smallwebwaf` would refuse and log what it would have done (see "What
it does so far" above).
- `SWWAF_TRUSTED_PROXIES` (default `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`,
the private address ranges): the netblocks whose `X-Forwarded-For` is
believed. A list given replaces the default; set but empty, it trusts nothing.
- `SWWAF_CLIENT_REQUEST_TIMEOUT` (default `60s`): how long a client may take to
send its request line and headers, and then, from the end of the headers, its
body.
- `SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES` (default `32K`): the largest request
line and headers a client may send. Over it, the answer is `431` and nothing
reaches the app. It must be more than `4K`, and cannot be `off`: Go's HTTP
server always has such a limit, and reads 4 KiB past the one it is given
before it refuses.
- `SWWAF_CLIENT_IDLE_TIMEOUT` (default `120s`): how long a kept-open connection
may wait for its next request before `smallwebwaf` closes it. The default is
longer than the 90 seconds after which traefik closes a connection it is not
using, so traefik never sends a request on a connection `smallwebwaf` is
closing.
- `SWWAF_CLIENT_RESPONSE_TIMEOUT` (default `30m`): how long the response may
take to reach the client, from the end of the request to the last byte.
- `SWWAF_UPSTREAM_REQUEST_TIMEOUT` (default `60s`): how long connecting to the
@@ -97,25 +193,89 @@ it, and the effective settings are logged at start.
to send its whole answer, from the end of the request to the last byte.
- `SWWAF_REQUEST_MAX_BYTES` (default `100M`): the largest request body.
- `SWWAF_RESPONSE_MAX_BYTES` (default `5G`): the largest response body.
- `SWWAF_ALLOW_NETS` (default empty): netblocks whose clients skip bans, the
country lists and the rate limits, such as your monitoring or your own
networks.
- `SWWAF_RATE_LIMIT_EXEMPT_NETS` (default empty): netblocks whose clients the
rate limits do not apply to, such as a machine that talks to the app all day.
- `SWWAF_DENY_NETS` (default empty): netblocks whose clients are always refused.
- `SWWAF_RATE_LIMIT_PER_MINUTE` (default `1000`), `SWWAF_RATE_LIMIT_PER_HOUR`
(default `10000`) and `SWWAF_RATE_LIMIT_PER_DAY` (default `50000`): the most
requests a client may make in a minute, an hour and a day. The defaults are
several times what one busy person produces, since a browser loading a heavy
page makes a few hundred requests and several people often share one address.
- `SWWAF_RATE_LIMIT_EXEMPT_PATHS` (default empty): path prefixes whose requests
the rate limits neither count nor refuse, such as `/assets/` for static
assets; each starts with `/`. A request whose path, percent-decoded, contains
`..` anywhere or a backslash, or whose path as sent holds an encoded slash
(`%2F` or `%2f`), is never exempt, since the app may act on it as a path
outside every prefix: `/assets/..%2Flogin` as `/login`. Any other request is
exempt when its path as sent, the path the app receives, before any query
string and not percent-decoded, starts with a prefix, character for character.
`/assets/` matches `/assets/app.js` and `/assets/`, but not `/assets`,
`/Assets/app.js`, `/%61ssets/app.js`, `/static/assets/app.js`,
`/static/../assets/app.js` or `/assets%2Fapp.js`. A character the client sends
percent-encoded, such as a space, is written percent-encoded in a prefix, as
in `/my%20files/`, and there are no wildcards: `*` is a character like any
other.
- `SWWAF_DENIED_COUNTRIES` (default empty): countries whose clients are refused,
for example `cn,ru,kp`.
- `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` (default empty): when set, the only
countries whose clients get through, for example `us,de`. A client whose
country cannot be found is refused too, so that new clients are not let in
whenever GeoJS stops answering.
- `SWWAF_BAN_RESPONSE` (default `403`): how a refused client is answered, one
that is banned, breaks a rate limit, is in `SWWAF_DENY_NETS` or comes from a
refused country: `403`, `429`, or `close` to close the connection without an
answer. Behind traefik, `close` does not leave the client unanswered: traefik
answers `502`, as it does whenever its backend drops a connection.
- `SWWAF_LIMIT_BAN_DURATION` (default `1h`): the ban for a first broken rate
limit.
- `SWWAF_LIMIT_BAN_REPEAT_WINDOW` (default `24h`): a rate limit broken again
within this time after a ban ended bans for three times as long as that ban.
- `SWWAF_MAX_BAN_DURATION` (default `7d`): a ban that would be longer is
permanent instead.
- `SWWAF_MAX_BANS` (default `5000`): the most bans kept, past, active and
permanent.
- `SWWAF_BAN_SCOPE_V4_PREFIX` (default `32`): the length of the netblock around
an IPv4 client that a ban covers, such as `24` to ban the surrounding /24. An
IPv6 ban covers the client's /64.
- `SWWAF_STATE_DIR` (default `/var/lib/smallwebwaf`): the directory of the state
files, an absolute path. A directory `smallwebwaf` cannot write stops the
start.
- `SWWAF_STATE_WRITE_DELAY` (default `10s`): how long after a ban is made
`bans.json` is written, with every ban made in between.
- `SWWAF_STATE_COUNTER_INTERVAL` (default `15m`): how often every state file is
written.
- `SWWAF_LOG_REQUEST_HEADERS` (default
`accept,accept-language,accept-encoding,content-type,origin,range`): the
request headers whose values the request log gives, in either case.
`Authorization`, `Cookie` and `Set-Cookie` are never logged, even when listed
(see "Request log" below). An entry naming `Host` or `Transfer-Encoding` stops
the start, since Go's HTTP server takes both out of the request; the request's
host is the field `host`.
- `SWWAF_METRICS_TOKEN` (default unset): the token a scraper sends for the
metrics, a long random value. While it is unset the metrics are off; one
shorter than 32 characters stops the start. The settings logged at start show
`********` in its place.
- `SWWAF_METRICS_TOP_N` (default `50`): how many countries get series of their
own in the metrics by country; the others are counted as `other`.
Durations are in Go's syntax, with `d` for days (`90s`, `15m`, `7d`). Sizes are
bytes, with an optional `K`, `M` or `G`, which are powers of 1024 (`1K` is 1024
bytes). Rate limits are whole numbers of requests. Netblocks are in CIDR form,
and a bare address stands for itself alone. `off` switches a timeout, a size
limit or a rate limit off.
and a bare address stands for itself alone. Countries are the two-letter codes
ISO 3166-1 assigns today, and `xk` for Kosovo, in either case (`de` and `DE` are
the same); any other code, such as `nk` (North Korea is `kp`) or the withdrawn
`su`, stops the start, and so does a code on both country lists. `off` switches
a timeout, a size limit or a rate limit off;
`SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES`, the ban settings, the state settings
and `SWWAF_METRICS_TOP_N` cannot be off.
Four limits are fixed rather than settings. The request line and headers may
take up to 32 KiB, above which the answer is `431` and nothing reaches the app.
A kept-open connection that sends nothing for 120 seconds is closed. That is
longer than the 90 seconds after which traefik closes a connection it is not
using, so traefik never sends a request on a connection `smallwebwaf` is
closing. At most 20,000 clients are kept for the rate limits, and an IPv6 client
is counted by its /64.
Several limits are fixed rather than settings. At most 20,000 clients are kept,
with their counters and history, and an IPv6 client is counted by its /64. A new
client waits at most a second for its country, and at most 100,000 answers from
GeoJS are kept, for 7 days each.
## Request log
@@ -123,34 +283,218 @@ is counted by its /64.
refused ones included:
```
{"type":"request","time":"2026-10-03T12:00:00.123Z","client_ip":"203.0.113.9","peer_ip":"172.18.0.2","method":"GET","host":"app.example","path":"/","query":"","protocol":"HTTP/1.1","status":200,"upstream_status":200,"request_bytes":0,"response_bytes":5120,"referer":"","user_agent":"curl/8.9.1","action":"forward","duration_total":3.217,"duration_upstream_total":3.104}
{"type":"request","time":"2026-10-03T12:00:00.123Z","instance":"fsn1app1/gitea","client_ip":"203.0.113.9","method":"GET","scheme":"https","host":"app.example","path":"/","query":"","protocol":"HTTP/1.1","status":200,"request_bytes":0,"response_bytes":5120,"referer":"","user_agent":"curl/8.9.1","request_id":"7Q2NHZ4KJ3VXW5YB6R3MEFTD2A","peer_ip":"172.18.0.2","forwarded_for":"203.0.113.9","client_group":"203.0.113.9/32","country":"DE","request_headers":{"accept":"*/*"},"response_content_type":"text/html; charset=utf-8","upstream_status":200,"action":"forward","counts":{"minute":1,"hour":12,"day":40},"duration_total":3.217,"duration_checks":0.041,"duration_upstream_connect":0.052,"duration_upstream_first_byte":2.874,"duration_upstream_total":3.104}
```
- `time` is when the request arrived, in UTC. `peer_ip` is the TCP peer,
normally traefik. `path` and `query` are as the client sent them.
A field that does not apply to a request is left out of its line, apart from
`type`, the fields from `time` to `user_agent`, `request_id`, `peer_ip`,
`client_group`, `country`, `action` and `duration_total`, which every line has.
- `time` is when the request arrived, in UTC. `instance` is
`SWWAF_INSTANCE_NAME`. `scheme` is the `X-Forwarded-Proto` a trusted proxy
sent, and otherwise `http`. `path` and `query` are as the client sent them.
- `request_id` is the `X-Request-ID` a trusted proxy sent, or a new random one
of 26 letters and digits when it sent none, or when the peer is not a trusted
proxy. A request passed to the app takes it there in `X-Request-ID`.
- `peer_ip` is the TCP peer, normally traefik. `forwarded_for` is the
`X-Forwarded-For` header as received, several lines of it joined with `, `.
`client_group` is the client as the rate limits count it: its IPv4 address as
a /32, or the /64 of its IPv6 address.
- `country` is the client's country as GeoJS places it. It is empty with neither
country list set, for a client in `SWWAF_ALLOW_NETS` or `SWWAF_DENY_NETS`, for
a client on a private, loopback or link-local address, when GeoJS cannot place
the client or has not answered in time, and for a request whose client a ban
covers, even when the client's country is known.
- `content_type` is the request's `Content-Type`, and `content_length` the
length the request announced for its body, which is left out for none or zero.
- `request_headers` are the request's headers that `SWWAF_LOG_REQUEST_HEADERS`
names, by name in lower case, several lines of one joined with `, `.
`Authorization`, `Cookie` and `Set-Cookie` are never among them, whatever the
setting says: `has_authorization` and `has_cookie` are there instead, and
true, when the request has an `Authorization` or a `Cookie` header.
- `websocket` is there, and true, when the app switched the connection to
another protocol, as it does for a WebSocket.
- `status` is what the client was sent, `0` if nothing was; `upstream_status` is
what the app answered, and is left out when the app did not answer.
- `response_content_type`, `cache_control` and `location` are the
`Content-Type`, `Cache-Control` and `Location` headers of the answer: the
app's, as passed on, or those of `smallwebwaf`'s own answer.
- `request_bytes` and `response_bytes` count body bytes.
- `action` is `forward` for a request passed to the app, `rate_limited` for one
refused for a rate limit, `too_large` for a request or response over its size
limit, `timed_out` for one that ran out of time, and `upstream_error` when the
app could not be reached or its answer broke off.
- `limit_hit` is there for a request refused for a rate limit, and names the
- `action` is `forward` for a request passed to the app, `denied` for one
refused because its client is in `SWWAF_DENY_NETS`, `banned` for one refused
because a ban covers its client, `country_denied` for one refused for its
client's country, `rate_limited` for one that broke a rate limit and banned
its client, `too_large` for a request or response over its size limit,
`timed_out` for one that ran out of time, `upstream_error` when the app could
not be reached or its answer broke off, and `admin` for one `smallwebwaf`
answered at its own endpoint.
- `would_action` is there in `observe` mode for a request that
`SWWAF_DENY_NETS`, a ban, the country lists or a rate limit would have refused
in `enforce` mode, and names the action that refusal would have had: `denied`,
`banned`, `country_denied` or `rate_limited`. `action` then names what was
done: `forward` for a request passed to the app, and another action, such as
`too_large`, for one a size or time limit refused.
- `counts` gives the client's requests in the minute, the hour and the day as
the rate limits count them, this request included: in each window, those in
the bucket under way and a share of those in the bucket before, so a count can
have a fraction. For a request that broke a limit, they are the counts that
broke it. It is left out for a request the rate limits do not count: the
health check, one from a client in `SWWAF_ALLOW_NETS` or
`SWWAF_RATE_LIMIT_EXEMPT_NETS`, one for a path that
`SWWAF_RATE_LIMIT_EXEMPT_PATHS` exempts, and one that `SWWAF_DENY_NETS`, a ban
or the country lists refuse, or would refuse in `observe` mode. The byte
totals come with the byte limits.
- `limit_hit` is there for a request that broke a rate limit, and names the
window whose limit it went over: `minute`, `hour` or `day`, the shortest if it
went over several.
went over several. `offence` is then `limit`.
- `ban_expires` is there for a request that made a ban or was refused under one,
or in `observe` mode would have been refused under one, and gives when the ban
ends, in the same form as `time`, or `permanent`.
- `aborted` is there, and true, when the client went away early.
- `duration_total` and `duration_upstream_total` are in milliseconds.
- The timings are in milliseconds, to the microsecond. `duration_total` runs
from when the request's headers had been read to when its line is written, and
`duration_checks` over the same start to when the checks were done; the health
check runs none, and its line has no `duration_checks`.
`duration_upstream_connect`, `duration_upstream_first_byte` and
`duration_upstream_total` are there for a request passed to the app, and run
from when it was handed to the app: until there was a connection to it, new or
kept open from an earlier request, until the first byte of its answer arrived,
and until the end. The first two are left out when that never happened, as for
an app that cannot be reached.
No body and no other header is logged. `smallwebwaf`'s own messages (start, the
settings, stop, errors) share the stream as JSON lines marked
No body is logged, and no header but those above. `smallwebwaf`'s own messages
(start, the settings, stop, errors) share the stream as JSON lines marked
`"type":"process"`.
Go's HTTP server, on which `smallwebwaf` is built, reads a request's line and
headers before `smallwebwaf` sees the request, and some requests end there,
without a line in the log: headers over 32 KiB, which it answers `431`, headers
slower than `SWWAF_CLIENT_REQUEST_TIMEOUT`, whose connection it closes without
an answer, and requests it cannot read at all, which it answers itself, mostly
with `400`.
without a line in the log: headers over `SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES`,
which it answers `431`, headers slower than `SWWAF_CLIENT_REQUEST_TIMEOUT`,
whose connection it closes without an answer, and requests it cannot read at
all, which it answers itself, mostly with `400`.
## State files
`smallwebwaf` keeps its state in memory and a copy of it in three JSON files in
`SWWAF_STATE_DIR`, `/var/lib/smallwebwaf` by default, as "Persistent state" in
[`SPEC.md`](SPEC.md) describes. Each has a top-level `version`, 1, and lists its
entries by client address, with times in UTC.
- `bans.json`: every ban with its notes, indented to be read; a permanent ban's
`expires` is `null`.
- `clients.json`: each client's two buckets in the minute, the hour and the day,
and its history: when it was first and last seen, its country as last looked
up and when, its requests, how many were forwarded and how many refused (one
`smallwebwaf` answered at its own endpoints is neither, unless it was refused
with `401` for a missing or wrong token), the body bytes in each direction,
its responses by status class and its offences by kind. Each client is on a
line of its own, so `grep` shows everything about one.
- `lookups.json`: GeoJS's answers, one to a line, with when GeoJS gave each and
when it was last used.
`bans.json` is written `SWWAF_STATE_WRITE_DELAY` after a ban is made, with every
ban made in between, and every file every `SWWAF_STATE_COUNTER_INTERVAL` and
when `smallwebwaf` stops. Each write goes to a temporary file in the same
directory, which then replaces the file, so a crash leaves the old file or the
new one, whole. A write that fails is logged, and tried again at the next write.
A hard kill loses what changed since the last write.
At start the files are read back: each client keeps its counts, so a restart
gives it no fresh allowance, and each ban keeps refusing every client in its
netblock until it ends, even after `SWWAF_BAN_SCOPE_V4_PREFIX` has changed. A
netblock whose address has bits past its length, such as `203.0.113.9/24`, is
read as the netblock it is in, `203.0.113.0/24`. Buckets and answers whose time
has passed are dropped. A missing file is empty state, as on a first start. A
file that does not parse, or has another `version`, stops the start with a
message naming the file, and the line and column where Go's JSON decoder gives
them; so does a state directory `smallwebwaf` cannot write. So does an entry
without a field it needs, named with the entry's place in the file: a ban's
`netblock`, `start` or `expires`, which is `null` for a permanent ban; a
client's `client`, or the `start` of a window in which it has requests; an
answer's `client`, `country`, which is `""` for a client GeoJS cannot place, or
`answered`. The AS number and AS name come with their lookup.
While it runs, `smallwebwaf` watches `SWWAF_STATE_DIR` and takes in your edit of
a state file as soon as you save it: what the file then holds replaces what
`smallwebwaf` held for it, as if read at start. It tells its own writes from
yours by comparing the file with what it last read or wrote, and before it
writes a file it takes in any edit made since, so your edit is not overwritten;
a change `smallwebwaf` made after you opened the file, such as a new ban, is
lost when you save over it. An edit that would stop the start, because it does
not parse, has another `version` or leaves out a field an entry needs, does not
stop the running `smallwebwaf`: it keeps what it holds, and at the file's next
write renames your file to `<name>.bad`, such as `bans.json.bad`, writes the
file again from memory, and logs the file and where the error is. It waits for
that write because an editor's file can be read before the editor has finished
writing it. Mend the `.bad` file and move it back. A file you remove is written
again at its next write.
To ban a netblock, add an entry to `bans.json` with its `netblock`, its `start`
and its `expires`, `null` for a ban that never ends; its `notes` may be left
out. This `bans.json` bans `203.0.113.0/24` for good:
```json
{
"version": 1,
"bans": [
{
"netblock": "203.0.113.0/24",
"start": "2026-10-06T12:00:00Z",
"expires": null
}
]
}
```
To lift a ban, delete its entry. `smallwebwaf` then forgets the ban, so it does
not make the netblock's next ban longer.
## Metrics
`GET /_smallwebwaf/metrics` answers with the metrics in the Prometheus text
format, for a scraper that sends `SWWAF_METRICS_TOKEN`, through traefik like any
other request. No metric carries a client's address.
- `smallwebwaf_requests_total`, `smallwebwaf_request_bytes_total` and
`smallwebwaf_response_bytes_total`: requests, and their body bytes each way,
by `status_class`, such as `2xx`, or `none` when nothing was sent, and by
`action`, as the request log names it.
- `smallwebwaf_request_duration_seconds`: how long requests took, and
`smallwebwaf_upstream_duration_seconds`: how long those passed to the app took
from then on, as histograms; `smallwebwaf_requests_in_flight`: the requests
under way.
- `smallwebwaf_rate_limit_hits_total` by `window`,
`smallwebwaf_size_and_time_limit_hits_total` by `limit`, the setting whose
limit was passed, `smallwebwaf_offences_total` by `kind`, and
`smallwebwaf_bans_made_total` by `cause`; `smallwebwaf_active_bans` and
`smallwebwaf_permanent_bans`.
- `smallwebwaf_country_requests_total`,
`smallwebwaf_country_request_bytes_total`,
`smallwebwaf_country_response_bytes_total`, and
`smallwebwaf_country_list_refusals_total`, the requests the country lists
refused, by `country`, for the requests whose client's country is known. The
`SWWAF_METRICS_TOP_N` countries with the most requests since the start have
series of their own, and the others are counted as `other`. A country that
drops out of them loses its series, and its later requests count as `other`;
one that comes into them gets a series that counts from then on.
- `smallwebwaf_geojs_requests_total`: the requests to GeoJS;
`smallwebwaf_geojs_failures_total`: those that failed, an answer that leaves
out an address asked about included; and `smallwebwaf_geojs_unanswered_total`:
the requests whose client counted as coming from an unknown country because
GeoJS had not answered about it in time.
- `smallwebwaf_tracked_clients`: the clients in the table of clients.
- `smallwebwaf_state_file_writes_total`,
`smallwebwaf_state_file_write_failures_total`,
`smallwebwaf_state_file_last_write_timestamp_seconds` and
`smallwebwaf_state_file_size_bytes`, by `file`; and, by `file` too,
`smallwebwaf_state_file_edits_taken_in_total`: your edits taken in, and
`smallwebwaf_state_file_edits_set_aside_total`: those renamed to `<name>.bad`
because they would stop the start.
- Go's own `go_` metrics and the process's `process_` metrics.
The requests Go's HTTP server ends before `smallwebwaf` sees them (see "Request
log") are not counted. The metrics of the features still to come, such as the
rule files, come with them.
## Why
@@ -253,9 +597,9 @@ goes through the candidates one by one.
readable JSON files, written regularly and at every stop, so a restart loses
nothing. Edit a file, or add a rule file, and the running `smallwebwaf` picks
up the change. Nothing is read from disk while serving a request. The files
come in milestone 3 or later (see the build order in [`SPEC.md`](SPEC.md));
until then the rate counters and the GeoJS answers are kept in memory only,
and a restart loses them.
for the bans, the clients and the GeoJS answers are built, with an edit taken
in while running (see "State files" above); the others come with their
features.
- Health checks, the metrics, and listing, adding and lifting bans or asking why
a given address was refused, all on the one port every request uses: under
`/_smallwebwaf/` on the app's own address, through traefik like any other
@@ -331,9 +675,9 @@ main "$@"
side by side, each as its own user, and start either again a second after it
exits. Leave out `ENTRYPOINT` and `USER` from the app's Dockerfile.
- `nix-env -iA nixpkgs.<name>` installs a package from the nixpkgs in the image,
and the app finds it on its `PATH`. That nixpkgs is fixed at one commit, so
the same `smallwebwaf` image always gives the app the same packages; newer
ones come with a newer `smallwebwaf` image.
and the app finds it on its `PATH`, after Ubuntu's own commands. That nixpkgs
is fixed at one commit, so the same `smallwebwaf` image always gives the app
the same packages; newer ones come with a newer `smallwebwaf` image.
- Deploy it as you deploy any app, with traefik's labels on this one container
pointing at port 8080. upaas needs no change for this.
- The app has to trust `127.0.0.1` and `::1` for forwarded headers, besides the
@@ -351,7 +695,11 @@ main "$@"
the health check on `127.0.0.1`.
- `smallwebwaf` keeps its state files in `/var/lib/smallwebwaf`. Mount a volume
there to keep bans and client history when a deploy replaces the container;
without one, it still starts.
without one, it still starts. At each start the `run` script of `smallwebwaf`
gives that directory and every file in it to the `smallwebwaf` user, so a host
directory mounted there needs no change of owner.
- `docker stop` has runit stop both processes. `smallwebwaf` then stops taking
requests and gives those in progress five seconds to finish.
A rule file is one rule per line: a name, what to match against, what to do, and
a regex.
@@ -367,14 +715,27 @@ the metrics, failure behaviour and the build order.
## Country and AS number lookup
`smallwebwaf` looks up the AS number and country of every client, for the
request log, the metrics and the ban notes, and for the country lists and biased
limits when you set them. It works with no setup: by default it asks the free
GeoJS web service, which needs no account and no file. This means that, by
default, the address of every new visitor is sent to GeoJS. Each answer is kept
in memory for seven days, and many addresses are asked about in one request;
writing the answers to disk, so that they survive a restart, comes in milestone
3 or later (see the build order in [`SPEC.md`](SPEC.md)). GeoJS publishes no
So far `smallwebwaf` looks up only the country, only through GeoJS, and only
while `SWWAF_DENIED_COUNTRIES` or `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` is set:
then the address of every new visitor is sent to GeoJS, except a visitor in
`SWWAF_ALLOW_NETS` or `SWWAF_DENY_NETS` and one whose netblock a ban covers, and
with neither set, none is. An IPv6 visitor is asked about by the first address
of its /64. A new visitor waits at most a second for its answer, and without one
counts as coming from an unknown country until the answer arrives. The addresses
waiting are asked about together, up to 200 in one request, one request at a
time; at most 10,000 visitors wait, and one more counts as coming from an
unknown country until there is room. While GeoJS fails, visitors with a kept
answer are unaffected and new ones count as coming from an unknown country.
GeoJS is then left alone for a second, twice as long after each further failure
up to five minutes, and asked again by the next request that needs it.
In the full design, `smallwebwaf` looks up the AS number and country of every
client, for the request log, the metrics and the ban notes, and for the country
lists and biased limits when you set them. It works with no setup: by default it
asks the free GeoJS web service, which needs no account and no file. This means
that, by default, the address of every new visitor is sent to GeoJS. Each answer
is kept for seven days, in memory and in `lookups.json`, so that it survives a
restart, and many addresses are asked about in one request. GeoJS publishes no
rate limit but may block a caller it thinks asks too much; while it is not
answering, new visitors count as coming from an unknown country, which
`SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` refuses.
@@ -382,47 +743,70 @@ answering, new visitors count as coming from an unknown country, which
To keep your visitors' addresses on your own host, set
`SWWAF_LOOKUP_SOURCE=off`, or use the database file instead of GeoJS:
`SWWAF_LOOKUP_SOURCE=file` reads the free IPinfo Lite database
(`ipinfo_lite.mmdb`). You download it with your own IPinfo account, mount the
directory that holds it into the container, point `SWWAF_LOOKUP_DB_PATH` at the
file and refresh it when you choose; `smallwebwaf` never downloads it itself,
and reads it again when you replace it. It has to be the directory rather than
the file itself: docker does not show a single mounted file being replaced, so a
refresh would go unseen. IPinfo releases it under the Creative Commons
Attribution-ShareAlike 4.0 International License and asks for attribution, in
its own words on https://ipinfo.io/lite: "The attribution requirements can be
met by giving our service credit as your data source. Simply place a link to
IPinfo on the website, application, or social media account that uses our data."
Its example of such a credit is a link mentioning "IP address data is powered by
IPinfo". A service that uses the database through `smallwebwaf` should carry
that link.
(`ipinfo_lite.mmdb`). `SWWAF_LOOKUP_SOURCE` comes in milestone 3 or later (see
the build order in [`SPEC.md`](SPEC.md)); until then GeoJS is asked only while a
country list is set. You download the database with your own IPinfo account,
mount the directory that holds it into the container, point
`SWWAF_LOOKUP_DB_PATH` at the file and refresh it when you choose; `smallwebwaf`
never downloads it itself, and reads it again when you replace it. It has to be
the directory rather than the file itself: docker does not show a single mounted
file being replaced, so a refresh would go unseen. IPinfo releases it under the
Creative Commons Attribution-ShareAlike 4.0 International License and asks for
attribution, in its own words on https://ipinfo.io/lite: "The attribution
requirements can be met by giving our service credit as your data source. Simply
place a link to IPinfo on the website, application, or social media account that
uses our data." Its example of such a credit is a link mentioning "IP address
data is powered by IPinfo". A service that uses the database through
`smallwebwaf` should carry that link.
Neither source can place a private address, so a client on one, such as a
visitor on your local network, another container or your monitoring, has no
country: `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` refuses it unless you list it in
`SWWAF_ALLOW_NETS`. Such addresses are never sent to GeoJS. In milestone 2,
which has no `SWWAF_ALLOW_NETS`, neither country list checks such a client; the
refusal comes with `SWWAF_ALLOW_NETS` in milestone 3 or later.
`SWWAF_ALLOW_NETS`, and `SWWAF_DENIED_COUNTRIES` does not refuse it. Such
addresses are never sent to GeoJS.
## How the code is laid out
- `cmd/smallwebwaf`: the binary, which only calls `internal/smallwebwaf`.
- `internal/smallwebwaf`: the process: it reads the settings, listens, serves
requests until `SIGTERM` or `SIGINT`, and stops.
- `internal/smallwebwaf`: the process: it reads the settings and the state
files, listens, serves requests until `SIGTERM` or `SIGINT`, and stops,
writing the state files. Run as `smallwebwaf healthcheck`, it is the image's
health check instead.
- `internal/config`: reads the settings, the one place they are read.
- `internal/proxy`: what happens to each request: it works out the client, runs
the checks, passes the request to the app and the answer back with the
standard library's `httputil.ReverseProxy` within the timeouts and size
limits, and writes the request's log line. Its `check` method is where a
request is refused before anything reaches the app: for a rate limit, for an
announced body over the size limit, and, with the rest of milestone 2, for the
country lists.
- `internal/ratelimit`: counts each client's requests and tells when one takes
it over a rate limit.
request is refused before anything reaches the app: for `SWWAF_DENY_NETS`, for
a ban, for the country lists, for a rate limit, which bans the client, and for
an announced body over the size limit; in `observe` mode, only for the size
limit, with what it would have refused for noted in the log line. A request
under `/_smallwebwaf/` that `check` lets through is answered by `answerAdmin`
instead of reaching the app.
- `internal/metrics`: the metrics, counted as the other parts tell it what
happened, and served in the Prometheus text format.
- `internal/bans`: the ban ledger: each netblock's bans with their notes, how
long a new ban lasts, and which ban is dropped when `SWWAF_MAX_BANS` are held.
- `internal/lookup`: looks up each client's country through GeoJS, and keeps the
answers.
- `internal/ratelimit`: the table of clients: counts each client's requests,
tells when one takes it over a rate limit, and keeps each client's history.
- `internal/state`: reads the state files at start, takes in an admin's edit of
one while running, and writes them when they are due and at the stop.
- `internal/requestlog`: the lines on stdout: the request log line and the
process's own messages.
- `Dockerfile`: the lint and test phases, then the image, whose last stage
installs Ubuntu's packages, nixpkgs, `runsvinit` and `smallwebwaf`, with
`share/smallwebwaf.run` as runit's `run` script for `smallwebwaf`.
- `deploy/example-app`: an app built on the image, which `script/example-app`
checks.
Besides the Go standard library, `github.com/hashicorp/golang-lru/v2` keeps the
table of clients to 20,000, dropping the least recently seen.
table of clients to 20,000, the GeoJS answers to 100,000 and the banned
netblocks to `SWWAF_MAX_BANS`, dropping the least recently seen, and
`github.com/prometheus/client_golang` keeps the metrics and serves them, and
`github.com/fsnotify/fsnotify` tells `smallwebwaf` when a state file is saved.
The country codes are the list in `internal/config/config.go`.
## Entrypoints
@@ -433,7 +817,7 @@ the `Makefile` targets are thin shims that call them. The scripts are POSIX sh,
so that they run in minimal containers.
- `script/bootstrap`: installs what the other scripts need on the host: `make`,
`git`, Go for `gofmt`, node and yarn, and prettier.
`git`, `curl`, Go for `gofmt`, node and yarn, and prettier.
- `script/setup`: readies a fresh clone: runs `script/bootstrap`, then
`script/install-precommit`.
- `script/projectname`: prints the project's name, `smallwebwaf`, which
@@ -451,13 +835,20 @@ so that they run in minimal containers.
- `script/install-precommit`: installs that hook; `make hooks` runs it.
- `script/build`: builds `bin/smallwebwaf` on the host, with Go installed, for
working on the code by hand; `make build` runs it.
- `script/run`: builds `bin/smallwebwaf` with `script/build` and runs it;
`make run` runs it.
- `script/run`: builds `bin/smallwebwaf` with `script/build` and runs it, with
its state files in `bin/state` unless `SWWAF_STATE_DIR` is set; `make run`
runs it.
- `script/example-app`: builds the image and, on it, the example app in
`deploy/example-app`, runs it with a volume for the state files, and checks
that the health check passes, that a request reaches the app through
`smallwebwaf`, that a second request in a minute bans the client, that
`sv stop` and `docker stop` stop it in order, and that a new container on the
same volume still refuses the banned client; then removes the containers, the
volume and both images. It needs network access, for nixpkgs' binary cache,
and `script/check` does not run it; `make example-app` does.
## TODO
- Milestone 2: the country lists and the image an app builds on
(https://git.eeqj.de/sneak/smallwebwaf/issues/14); its rate limits are built.
- The rest of the design, in the order of the build order in
[`SPEC.md`](SPEC.md).
REPO_POLICIES.md
+120 -44
View File
@@ -1,6 +1,6 @@
---
title: Repository Policies
last_modified: 2026-09-08
last_modified: 2026-10-04
---
This document covers repository structure, tooling, and workflow standards. Code
@@ -104,10 +104,14 @@ style conventions are in separate documents:
`lint` phase and a `test` phase, with the final stage depending on both so the
image cannot be built unless they pass. For non-server repos the final stage
brings up a development environment; for server repos it is the runtime image.
Dockerfiles install development prerequisites by running `script/bootstrap`
rather than duplicating installs inline; COPY `script/` and the dependency
manifests (`package.json` + `yarn.lock`, `go.mod` + `go.sum`, etc.) before
running it.
The gate phases and the build stage start from their pinned base images and
install what those images lack either inline, as the canonical Go `Dockerfile`
below does for `git`, or by running `script/bootstrap`, as the `prompts`
repo's own `Dockerfile` does for its yarn packages. The development
environment stage installs development prerequisites by running
`script/bootstrap` rather than duplicating its installs inline. A stage that
runs `script/bootstrap` COPYs `script/` and the dependency manifests
(`package.json` + `yarn.lock`, `go.mod` + `go.sum`, etc.) before running it.
- **Linting and testing run in Docker, as phases of the `Dockerfile`.** There is
no separate lint file. `script/lint` and `script/test` each build one phase
@@ -156,11 +160,14 @@ style conventions are in separate documents:
not evidence that anything ran: a sub-second build reporting success is a
cache hit, not a result. Never invalidate by pruning — `docker builder prune`
and friends destroy a build cache shared with every other build on the host.
When a check is added or changed, prove it works by planting a defect it must
catch and watching the run fail on it, then revert the defect. A green run
alone shows neither that the check ran nor that it covers what it should.
- **The gate phases are separate stages, and the build stage depends on both.**
The lint phase is based on the `golangci/golangci-lint` image (pinned by
hash), so lint failures surface in seconds rather than after a full compile,
and the test phase is based on the Go image. The canonical Go repo
and the test phase is based on the Debian Go image. The canonical Go repo
`Dockerfile`:
```dockerfile
@@ -173,8 +180,9 @@ style conventions are in separate documents:
COPY . .
RUN golangci-lint run --config .golangci.yml ./...
# Test phase
# golang:1.x-alpine, YYYY-MM-DD
# Test phase. -race needs cgo and so a C compiler, which the Debian Go
# image ships and the alpine one does not.
# golang:1.x, YYYY-MM-DD
FROM golang@sha256:... AS test
WORKDIR /src
COPY go.mod go.sum ./
@@ -191,15 +199,29 @@ style conventions are in separate documents:
FROM golang@sha256:... AS builder
COPY --from=lint /src/go.sum /dev/null
COPY --from=test /src/go.sum /dev/null
RUN apk add --no-cache git
# A tar-stream context keeps the sender's file owners, which git refuses.
RUN git config --system --add safe.directory /src
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
ARG VERSION=dev
RUN CGO_ENABLED=0 go build -trimpath \
-ldflags="-s -w -X main.Version=${VERSION}" \
-o /app ./cmd/app/
# The VERSION build arg when one is given, otherwise
# `git describe --tags --always` on the .git in the build context. With
# .git present, a version that is still empty, dev or unknown fails the
# build: git is missing or could not read the checkout.
ARG VERSION
RUN VERSION="${VERSION:-$(git describe --tags --always)}"; \
if [ -e .git ]; then \
case "$VERSION" in ""|dev|unknown) \
echo "version is '$VERSION' although .git is present" >&2; \
exit 1 ;; \
esac; \
fi; \
CGO_ENABLED=0 go build -trimpath \
-ldflags="-s -w -X main.Version=${VERSION}" \
-o /app ./cmd/app/
# Runtime stage, and the last one
FROM alpine@sha256:...
@@ -221,10 +243,41 @@ style conventions are in separate documents:
(e.g. a web frontend compiled in a separate stage), the lint phase must
create placeholder files so the embed directives resolve. Example:
`RUN mkdir -p web/dist && touch web/dist/index.html web/dist/style.css`.
- If the project requires CGO or system libraries for linting (e.g.
`vips-dev`), install them in the lint phase with `apk add`.
- `ARG VERSION=dev` is declared in the stage that compiles and supplied by
`script/docker` and `script/cibuild`; no stage may call `git describe`.
- If the project requires CGO or system libraries for linting, install them
in the lint phase. The `golangci/golangci-lint` image is Debian-based and
has no `apk`, so install with `apt-get` under the Debian package name
(`libvips-dev`, where alpine says `vips-dev`), and delete the package
lists in the same `RUN`, so the layer does not keep them:
```dockerfile
RUN apt-get update \
&& apt-get install -y --no-install-recommends libvips-dev \
&& rm -rf /var/lib/apt/lists/*
```
- `.dockerignore` lets `.git` into the build context. It keeps out every git
`config` at any depth (`**/.git/config`, `**/.git/modules/**/config`): the
repository's own, each submodule's under `.git/modules/`, and that of a
submodule keeping its own `.git` directory. `git describe` does not need
them, and each can hold a credential: a password in a remote URL, or the
token the CI checkout step stores there. A submodule whose name has a
`config` segment (`config`, `deploy/config`, `config/lib`) loses its whole
git directory to `**/.git/modules/**/config`, and Go's version stamping
then fails the build: give it a name without that segment
(`git submodule add --name`). The stage that compiles has `git` (the
Debian Go image has it; an alpine one needs `apk add --no-cache git`) and
takes the version from the `VERSION` build argument when one is given,
otherwise from `git describe --tags --always`. That gives the tag on a
tagged commit; on a later commit, the tag, the number of commits since it
and the short commit (`v1.2.3-4-gabc1234`); and the short commit when no
tag is reachable. The stage that compiles also marks its working directory
safe for git (`git config --system --add safe.directory /src`): a context
sent as a tar stream keeps the sender's file owners, and git refuses a
checkout owned by another user, so the version would come out empty.
`ARG VERSION` has no default, and the build fails if the context carries
`.git` and the version still comes out empty, `dev` or `unknown`. A plain
`docker build .` with no build arguments must succeed; a Dockerfile that
refuses an empty build argument drops that refusal and keeps the argument.
- Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
runs `script/cibuild` on push, and checks out the repo as its only other step.
@@ -233,7 +286,12 @@ style conventions are in separate documents:
carry the same guarantee, because its gate phases may come from the cache. The
image build is uncached and so runs the gate phases a second time. That is the
price of the rule above, and it is worth paying: the image that ships is built
from a run of its own gates rather than from a cache entry.
from a run of its own gates rather than from a cache entry. A separate
workflow limited to `main` by a `branches` list under `on: push` cannot be
checked by review: to try a change to it, add the feature branch to that list
and push, then remove the branch from the list again before merging. Keep any
job in it that publishes behind `if: github.ref_name == 'main'`, so the run
from the feature branch publishes nothing.
- Use platform-standard formatters: `black` for Python, `prettier` for
JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
@@ -286,17 +344,19 @@ style conventions are in separate documents:
```
`-count=1` is required on both invocations: it defeats Go's test _result_
cache, so the target cannot report a pass it did not earn, and the rerun
reproduces a failure instead of replaying it. It leaves the build cache
alone, so it costs the runtime of the suite and no recompilation.
cache, so neither run can report a stored pass in place of running the
tests. It leaves the build cache alone, so it costs the runtime of the suite
and no recompilation.
Note that this is a second, independent cache, stacked below the Docker
layer cache that [issue #26](https://git.eeqj.de/sneak/prompts/issues/26)
addresses. `CHECK_EPOCH` guarantees the `RUN make test` _step_ re-executes;
it does not guarantee `go test` inside that step does any work, because the
`GOCACHE` baked into earlier image layers survives into the re-executed
step. They are two separate defects requiring two separate fixes, and a fix
for one must not be recorded as covering the other.
That cache is Go's own, separate from Docker's layer cache. Go stores a
passing result in its cache directory (`GOCACHE`), and when the same tests
run again on unchanged code it prints that result, marked `(cached)`,
without running them. That matters on a developer's machine, where this
target runs and the directory lasts from one run to the next. The `test`
phase of the `Dockerfile` needs no `-count=1`: its base image holds no
result for this repo's tests and nothing before its `go test` step runs a
test, so there is nothing to replay. `--no-cache` (above) is what makes that
step run on an unchanged tree.
Python example:
@@ -340,7 +400,7 @@ style conventions are in separate documents:
— which is more dangerous than a short file with no secret patterns at all,
because it reads as solved and stops anyone looking. Give every
depth-independent pattern the `**/` prefix and leave only genuinely
root-anchored entries unprefixed: `.git`, and the repo's own host-built
root-anchored entries unprefixed: `.claude`, and the repo's own host-built
binary, written `/myapp` and never `**/myapp`, which would also match
`cmd/myapp/` and delete the package directory from the context. Matching is
case-sensitive, and an ALL-CAPS twin per pattern still misses `Server.Key`, so
@@ -365,12 +425,13 @@ style conventions are in separate documents:
directory, so a repo running agents in subdirectories still ships
`services/api/.claude/` and must add its own anchored entry there.
- **Excluding `.git` means `git describe` cannot run inside any build stage, and
it fails quietly there.** In a build stage there is no repository, so
`git describe` writes nothing to stdout, `-X main.Version=` comes out empty,
the binary reports no version at all, and the build still exits 0. Compute the
version on the host and thread it in as a build arg. `script/docker` and
`script/cibuild` do this, byte-identically across repos:
- **A plain `docker build .` of a clone stamps the version that
`git describe --tags --always` gives**, derived from the `.git` in the build
context as the canonical `Dockerfile` above shows. Without its failure check,
a missing `git` or an unreadable checkout would leave `-X main.Version=` empty
and the build would still exit 0. `script/docker` and `script/cibuild` pass
the version they compute on the host; it takes precedence. They do this
byte-identically across repos:
```sh
# Own line: a failing command substitution inside an argument does not
@@ -387,7 +448,7 @@ style conventions are in separate documents:
fallback is applied — a live check that fires on a build from an export with
no `.git` and on a repository with no commits yet. Do not fold it into the
substitution as `|| echo unknown`, which makes the guard unreachable. The
Dockerfile's side is `ARG VERSION=dev` in the stage that compiles, declared
Dockerfile's side is `ARG VERSION` in the stage that compiles, declared
there because `ARG` is stage-scoped; passing `VERSION` to a repo whose
Dockerfile declares no such `ARG` is ignored and costs nothing, which is why
the scripts stay byte-identical. One consequence for CI: the standard
@@ -426,12 +487,18 @@ style conventions are in separate documents:
`test-support` depguard rule, where a repo names its own test-support packages
by full import path. A repo adds entries there and changes nothing else, and a
re-vendor carries its entries forward. The canonical golangci-lint version is
v2.12.2 (released 2026-05-06), pinned as the digest of the lint phase's base
v2.14.0 (released 2026-09-24), pinned as the digest of the lint phase's base
image
(`golangci/golangci-lint@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240`,
which reports `2.12.2 built with go1.26.2 from c0d3ddc9`). That digest is the
only pin, since no repo installs golangci-lint on the host: bumping the
version means changing it and nothing else.
(`golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f`,
which reports `2.14.0 built with go1.27.0 from 114493f9`). A module's `go`
directive must not name a newer Go minor version than the one golangci-lint
was built with, or golangci-lint refuses to lint it: this release lints
`go 1.27.1` but not `go 1.28`. That digest is the only pin, since no repo
installs golangci-lint on the host. A repo sets the lint phase digest to the
one named here and re-vendors `.golangci.yml` in the same commit, whichever of
the two prompted the change: the canonical copy can name linters that an older
golangci-lint rejects, and a newer golangci-lint can add linters that
`default: all` switches on until the canonical copy disables them.
- **`script/bootstrap` installs a pinned tool by comparing versions, never by
testing presence.** An `if ! command -v <tool>; then install; fi` guard tests
@@ -455,6 +522,11 @@ style conventions are in separate documents:
Keep it POSIX sh: no arrays, no `[[`, no `grep -P`.
A Go tool a repo needs on the host is installed with `go install` pinned to
a commit hash (`go install <package>@<commit hash>`). It is never tracked as
a `go.mod` tool dependency or through a `tools.go` file, either of which
pulls the tool's own dependencies into the repo's `go.mod` and `go.sum`.
- When pinning images or packages by hash, add a comment above the reference
with the version and date (YYYY-MM-DD).
@@ -567,10 +639,10 @@ style conventions are in separate documents:
settings.
- Avoid putting files in the repo root unless necessary. Root should contain
only project-level config files (`README.md`, `Makefile`, `Dockerfile`,
`LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`, and
language-specific config). Everything else goes in a subdirectory. Canonical
subdirectory names:
only project-level config files (`README.md`, `AGENTS.md`, `Makefile`,
`Dockerfile`, `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`,
and language-specific config). Everything else goes in a subdirectory.
Canonical subdirectory names:
- `bin/` — executable scripts and tools
- `cmd/` — Go command entrypoints; thin only: one `main.go` per binary whose
body is a single call into `internal/` or `pkg/`, no project logic in
@@ -601,3 +673,7 @@ style conventions are in separate documents:
- Go: `go.mod`, `go.sum`, `.golangci.yml`
- JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
- Python: `pyproject.toml`
- Guidance for coding agents lives in one `AGENTS.md` at the repository root. It
is never committed under a file or directory named after one agent tool, such
as `CLAUDE.md` or `.claude/`, and never split into separate memory files.
SPEC.md
+52 -36
View File
@@ -293,7 +293,8 @@ it.
needs: an alert destination, an account key, a token.
- Every setting's name starts with `SWWAF_`, since `smallwebwaf` shares its
container, and so its environment variables, with the app it protects.
- Any limit or threshold can be switched off with the value `off`.
- Any limit or threshold can be switched off with the value `off`, except
`SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES`.
- A list set to an empty value is an empty list, and replaces the default.
- Every setting may instead be given as a file holding the value, named by the
setting's name with `_FILE` added, such as `SWWAF_ADMIN_TOKEN_FILE`, for
@@ -413,7 +414,9 @@ The settings, by group:
headers, its body.
- `SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES` (default `32K`): the largest
request line and headers a client may send. Over it, `smallwebwaf` answers
`431` and closes the connection, and nothing reaches the app.
`431` and closes the connection, and nothing reaches the app. It must be
more than `4K`, and cannot be `off`: Go's HTTP server always has such a
limit, and reads 4 KiB past the one it is given before it refuses.
- `SWWAF_CLIENT_IDLE_TIMEOUT` (default `120s`): how long a kept-open
connection may wait for its next request before `smallwebwaf` closes it.
It is longer than the 90 seconds after which traefik, by default, closes a
@@ -945,9 +948,9 @@ and the running `smallwebwaf` takes the edit in.
- what was broken: the rule ids and target that matched, or the limit, its
window, the count reached and the client's limit percentage with what set
it; and any reputation sources that listed the client;
- the requests that caused the ban, up to the last ten: time, method, host,
path with its query string, status and user agent, each text cut to 256
bytes;
- the request that caused the ban, the one that broke the limit or carried
the clear sign of attack: time, method, host, path with its query string,
status and user agent, each text cut to 256 bytes;
- how many requests counted toward the ban, and the time span over which
they came;
- the netblock's total requests since it was first seen, and the requests
@@ -958,13 +961,13 @@ and the running `smallwebwaf` takes the edit in.
the table is full, so on a public service the file grows to the default
`SWWAF_MAX_TRACKED_CLIENTS` of 20,000, about 20 MiB. Written every 15
minutes, that is under 2 GiB of disk writes a day.
- `bans.json` takes about 2 KiB per ban and at most about 8 KiB, since the
texts in the notes are cut short. At the default `SWWAF_MAX_BANS` of 5,000
it is about 10 MiB, and never more than about 40 MiB, plus whatever bans
an admin made. It is written when a ban is made, lifted or made permanent,
at most once every 10 seconds, and otherwise with the 15-minute write, so
its writes follow the bans made: with a full file, a hundred new bans a
day come to about 1 GiB of disk writes.
- `bans.json` takes about 1.2 KiB per ban and at most about 2.5 KiB, since
the notes hold one request and their texts are cut short. At the default
`SWWAF_MAX_BANS` of 5,000 it is about 6 MiB, and never more than about 12
MiB, plus whatever bans an admin made. It is written when a ban is made,
lifted or made permanent, at most once every 10 seconds, and otherwise
with the 15-minute write, so its writes follow the bans made: with a full
file, a hundred new bans a day come to about 600 MiB of disk writes.
- `lookups.json` takes about 150 bytes per answer, about 15 MiB when full.
Written every 15 minutes, that is under 1.5 GiB of disk writes a day.
- `reputation.json` and `alerts.json` are usually a few MiB or less.
@@ -1263,14 +1266,19 @@ image's digest does. `apt-get update` keeps the snapshot's `InRelease` files,
which apt checks against the archive's signature, in `/var/lib/apt/lists/`; each
lists the SHA-256 hash of the package lists it covers, and each package list the
hash of every package in it. The Dockerfile also names the SHA-256 hash of each
`InRelease` file apt uses, and the build checks them after `apt-get update` and
before `apt-get install`, so every package apt installs is checked, through
those files, against hashes the Dockerfile names. The snapshot service is
reached over HTTPS, and the Ubuntu image has no CA certificates of its own, so
this one install uses those of the Go image that `smallwebwaf` is built in,
which is pinned by digest too: apt's `Acquire::https::CaInfo` option names that
image's CA certificate file, `/etc/ssl/certs/ca-certificates.crt`, copied into
the build.
of the snapshot's `InRelease` files, and the build checks them after
`apt-get update` and before `apt-get install`, so every package apt installs is
checked, through those files, against hashes the Dockerfile names.
`apt-get update` also fetches the live archive's `InRelease` files into the same
directory; their hashes change whenever the archive does, and the install does
not use them, so the check leaves them out. The hashes are those of the archive
for amd64, and so the image is built for amd64: other architectures use Ubuntu's
ports archive, whose `InRelease` files differ. The snapshot service is reached
over HTTPS, and the Ubuntu image has no CA certificates of its own, so this one
install uses those of the Go image that `smallwebwaf` is built in, which is
pinned by digest too: apt's `Acquire::https::CaInfo` option names that image's
CA certificate file, `/etc/ssl/certs/ca-certificates.crt`, mounted for that one
step.
Packages from nixpkgs: nixpkgs is fixed at one commit of its newest release
branch, `nixos-26.05` today. For each commit of the branch that has passed its
@@ -1281,15 +1289,18 @@ bytes can change. The image's Dockerfile names the release and the SHA-256 hash
of that file, which the release's page lists, and the build checks the hash
before unpacking it. nixpkgs is set up for root under the name `nixpkgs`, so the
app's Dockerfile installs a package with `nix-env -iA nixpkgs.<name>`, and
whatever it installs is on the `PATH` of every service. Because nixpkgs stays at
that commit, an app built on the same `smallwebwaf` image gets the same packages
each time it is built. Unpacked, nixpkgs takes about 500 MiB of disk, more on
some filesystems such as ZFS, and each package an app installs from it adds its
own size, with everything it depends on. A newer commit of the branch, with its
security fixes, comes with a newer `smallwebwaf` image, as do Ubuntu's own
fixes; an app takes them by changing the digest in its `FROM` line. When nixpkgs
makes its next release, every six months, the image moves to that release's
branch.
whatever it installs is on the `PATH` of every service: the image adds root's
Nix profile, `/nix/var/nix/profiles/default/bin`, at the end of the `PATH`,
after Ubuntu's own directories, so that no package hides the image's own
commands. busybox, for one, brings its own `sv`, which looks for services
elsewhere. Because nixpkgs stays at that commit, an app built on the same
`smallwebwaf` image gets the same packages each time it is built. Unpacked,
nixpkgs takes about 500 MiB of disk, more on some filesystems such as ZFS, and
each package an app installs from it adds its own size, with everything it
depends on. A newer commit of the branch, with its security fixes, comes with a
newer `smallwebwaf` image, as do Ubuntu's own fixes; an app takes them by
changing the digest in its `FROM` line. When nixpkgs makes its next release,
every six months, the image moves to that release's branch.
The two processes:
@@ -1315,12 +1326,15 @@ The two processes:
- The container's root filesystem stays writable: runit writes each service's
status into its directory under `/etc/service`.
The health check: the image's `HEALTHCHECK` passes while `smallwebwaf` answers
`GET /_smallwebwaf/healthz` on `127.0.0.1`, at the port in `SWWAF_LISTEN_ADDR`,
and the app accepts connections at the address in `SWWAF_UPSTREAM_URL`, and
fails when either does not. The container therefore shows as healthy only while
both processes are up. An app with a health check of its own can replace the
image's `HEALTHCHECK` with one that checks both.
The health check: the image's `HEALTHCHECK` runs `smallwebwaf healthcheck`,
which passes while `smallwebwaf` answers `GET /_smallwebwaf/healthz` on
`127.0.0.1`, at the port in `SWWAF_LISTEN_ADDR`, and the app accepts connections
at the address in `SWWAF_UPSTREAM_URL`, and fails when either does not. The
container therefore shows as healthy only while both processes are up. traefik
sends a container no requests until it shows as healthy, so the check runs every
second from the container's start until it first passes, for up to a minute, and
every 30 seconds after that. An app with a health check of its own can replace
the image's `HEALTHCHECK` with one that checks both.
Ports: `smallwebwaf` listens on port 8080 on every address and on no other port;
its health check, metrics and ban management are all on that listener, under
@@ -1609,7 +1623,9 @@ holds any token file.
- The container image described under "Deployment", with runit and the
container's health check. The health check calls `/_smallwebwaf/healthz`,
so milestone 2 answers that path, although the other admin endpoints come
later.
later. The image's `/var/lib/smallwebwaf`, which the `run` script gives to
the `smallwebwaf` user, and `/etc/smallwebwaf/rules.d` come with the state
files and the rule files.
- Milestone 3 and later: the rest of the design, in this order:
- static lists, the bans that broken request limits lead to, the ban ledger
and the JSON state files with edits taken in while running, exemptions,
deploy/example-app/Dockerfile
+20
View File
@@ -0,0 +1,20 @@
# An app built on the smallwebwaf image, as under "Deployment" in
# SPEC.md, which script/example-app builds and checks. The app is
# busybox's web server, from the nixpkgs in the image, serving one page;
# a real app copies in its own binary instead.
#
# A real app names the smallwebwaf image by digest. This one takes the
# image script/example-app has just built, or else the one `make docker`
# builds.
ARG SMALLWEBWAF_IMAGE=smallwebwaf
FROM ${SMALLWEBWAF_IMAGE}
# Packages the app needs, from the nixpkgs in the image.
RUN nix-env -iA nixpkgs.busybox
# The app's page, and a user of its own to run it.
RUN mkdir /var/www && echo 'hello from the example app' > /var/www/index.html
RUN useradd --system --no-create-home --shell /usr/sbin/nologin app
# The app's runit service.
COPY --chmod=755 app.run /etc/service/app/run
deploy/example-app/app.run
Executable
+9
View File
@@ -0,0 +1,9 @@
#!/usr/bin/env bash
set -euo pipefail
main() {
sleep 1
exec chpst -u app:app busybox httpd -f -p 127.0.0.1:8081 -h /var/www
}
main "$@"
go.mod
+17 -1
View File
@@ -2,4 +2,20 @@ module sneak.berlin/go/smallwebwaf
go 1.26.0
require github.com/hashicorp/golang-lru/v2 v2.0.7
require (
github.com/fsnotify/fsnotify v1.10.1
github.com/hashicorp/golang-lru/v2 v2.0.7
github.com/prometheus/client_golang v1.24.1
)
require (
github.com/beorn7/perks v1.0.1 // indirect
github.com/cespare/xxhash/v2 v2.3.0 // indirect
github.com/kylelemons/godebug v1.1.0 // indirect
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
github.com/prometheus/client_model v0.6.2 // indirect
github.com/prometheus/common v0.70.1 // indirect
github.com/prometheus/procfs v0.21.1 // indirect
golang.org/x/sys v0.47.0 // indirect
google.golang.org/protobuf v1.36.11 // indirect
)
go.sum
+38
View File
@@ -1,2 +1,40 @@
github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/fsnotify/fsnotify v1.10.1 h1:b0/UzAf9yR5rhf3RPm9gf3ehBPpf0oZKIjtpKrx59Ho=
github.com/fsnotify/fsnotify v1.10.1/go.mod h1:TLheqan6HD6GBK6PrDWyDPBaEV8LspOxvPSjC+bVfgo=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
github.com/klauspost/compress v1.19.1 h1:VsB4HPswih7mmZ8WleSFQ75c/Ui1M4trX5oAsJnhSlk=
github.com/klauspost/compress v1.19.1/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/prometheus/client_golang v1.24.1 h1:JnJkREXzWxUdCuPFpIWZiPispT9xVV59uiuyR2bPlnU=
github.com/prometheus/client_golang v1.24.1/go.mod h1:F+oSRECHg4sse5ucfYpYDeIv/hu68Zo0uoHKetWnzcE=
github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
github.com/prometheus/common v0.70.1 h1:1HvjP4D5oL3t8RsPlwxA9onvvStjtIHYE5XuuwOi/PY=
github.com/prometheus/common v0.70.1/go.mod h1:VdFUQDMZK3VLkurFUVhia6uys/0suUp86TJz5qbJRhc=
github.com/prometheus/procfs v0.21.1 h1:GljZCt+zSTS+NZq88cyQ1LjZ+RCHp3uVuabBWA5+OJI=
github.com/prometheus/procfs v0.21.1/go.mod h1:aB55Cww9pdSJVHk0hUf0inxWyyjPogFIjmHKYgMKmtY=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
go.yaml.in/yaml/v2 v2.4.4 h1:tuyd0P+2Ont/d6e2rl3be67goVK4R6deVxCUX5vyPaQ=
go.yaml.in/yaml/v2 v2.4.4/go.mod h1:gMZqIpDtDqOfM0uNfy0SkpRhvUryYH0Z6wdMYcacYXQ=
golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
internal/bans/bans.go
+437
View File
@@ -0,0 +1,437 @@
// Package bans is the ban ledger: the bans smallwebwaf makes on the
// netblocks of clients that break a rate limit, with their notes, as the
// "Bans" section of SPEC.md describes. The bans are kept in memory, and
// written to bans.json and read from it by the state package.
package bans
import (
"net/netip"
"slices"
"strings"
"sync"
"time"
"github.com/hashicorp/golang-lru/v2/simplelru"
)
// repeatFactor is how many times as long as the netblock's last ban a ban
// for a limit broken again within the repeat window lasts.
const repeatFactor = 3
// maxTextBytes is how much of each text in a ban's notes is kept.
const maxTextBytes = 256
// Rules are how long a ban for a broken limit lasts, and how many bans
// are held.
type Rules struct {
// LimitBanDuration is how long a first ban lasts.
LimitBanDuration time.Duration
// LimitBanRepeatWindow is how soon after the end of the netblock's
// ban that ended last a broken limit counts as a repeat, which bans
// for repeatFactor times as long as that ban.
LimitBanRepeatWindow time.Duration
// MaxBanDuration is the longest ban; a ban that would be longer is
// permanent instead.
MaxBanDuration time.Duration
// MaxBans is the most bans held, at least one. Past it, the earliest
// ban of the netblock that has gone longest without a request is
// dropped.
MaxBans int
}
// Ban is a ban on a netblock for a broken limit, the only kind of ban
// smallwebwaf makes so far.
type Ban struct {
Netblock netip.Prefix
Start time.Time
// Expires is when the ban ends, zero for a permanent ban.
Expires time.Time
Notes Notes
}
// Permanent reports whether the ban never runs out.
func (b Ban) Permanent() bool {
return b.Expires.IsZero()
}
// ActiveAt reports whether the ban refuses requests at now.
func (b Ban) ActiveAt(now time.Time) bool {
return b.Permanent() || now.Before(b.Expires)
}
// Notes are what an admin needs to decide whether to lift a ban. The
// JSON names are those of bans.json.
//
//nolint:tagliatelle // the state files use snake_case, as the request log does
type Notes struct {
// Country is the client's country, when it was looked up.
Country string `json:"country"`
// Limit, Window and Count are the limit that was broken, its window,
// "minute", "hour" or "day", and the count reached: the client's
// requests in the window, the one that broke the limit included.
// These are the requests that counted toward the ban, and the window
// is the time over which they came.
Limit int64 `json:"limit"`
Window string `json:"window"`
Count float64 `json:"count"`
// Request is the request that broke the limit.
Request Request `json:"request"`
// Requests is how many requests the netblock has sent since it was
// first seen, and Refused how many of them the ban has refused so
// far. Both go up with each request the ban refuses.
Requests int64 `json:"requests"`
Refused int64 `json:"refused"`
// EarlierBans is how many bans the netblock had before this one.
EarlierBans int `json:"earlier_bans"`
}
// Request is a request in a ban's notes. Each text is cut to 256 bytes.
//
//nolint:tagliatelle // the state files use snake_case, as the request log does
type Request struct {
Time time.Time `json:"time"`
Method string `json:"method"`
Host string `json:"host"`
// Path is the path with its query string.
Path string `json:"path"`
// Status is what the client was sent, 0 if nothing was.
Status int `json:"status"`
UserAgent string `json:"user_agent"`
}
// Ledger holds the bans. It is safe for concurrent use.
type Ledger struct {
rules Rules
// changed receives a value when a ban is made, unless one is waiting
// already.
changed chan struct{}
mu sync.Mutex
// netblocks holds each banned netblock's bans, oldest first. Check and
// Find make each netblock they find the most recently seen.
netblocks *simplelru.LRU[netip.Prefix, *[]Ban]
// held is how many bans netblocks holds, at most rules.MaxBans.
held int
// made is how many bans BanForLimit has made since the start.
made int
// v4Lengths and v6Lengths are the lengths of the IPv4 and IPv6
// netblocks that have been banned. Check looks for a ban at each of
// them, so that a ban read from bans.json refuses every client in its
// netblock even when it was made with another SWWAF_BAN_SCOPE_V4_PREFIX,
// or another length of an IPv6 client's netblock.
v4Lengths, v6Lengths []int
}
// New returns a Ledger with no ban yet.
func New(rules Rules) *Ledger {
// Every netblock held has a ban, so there are never more netblocks
// than rules.MaxBans, and the LRU never drops one itself.
netblocks, err := simplelru.NewLRU[netip.Prefix, *[]Ban](rules.MaxBans, nil)
if err != nil {
panic(err) // NewLRU fails only for a size below one
}
return &Ledger{
rules: rules,
changed: make(chan struct{}, 1),
netblocks: netblocks,
}
}
// Changed receives a value after a ban is made, so that bans.json can be
// written. Several bans made before it is read leave one value.
func (l *Ledger) Changed() <-chan struct{} {
return l.changed
}
// Check is called for a request from client, at now. It reports whether
// a ban on a netblock client is in is active, and returns that ban, with
// the request counted among those it refused.
func (l *Ledger) Check(client netip.Addr, now time.Time) (Ban, bool) {
l.mu.Lock()
defer l.mu.Unlock()
ban := l.active(client, now)
if ban == nil {
return Ban{}, false
}
ban.Notes.Requests++
ban.Notes.Refused++
return *ban, true
}
// Find is Check without counting the request among those the ban
// refused: in observe mode a ban refuses nothing.
func (l *Ledger) Find(client netip.Addr, now time.Time) (Ban, bool) {
l.mu.Lock()
defer l.mu.Unlock()
ban := l.active(client, now)
if ban == nil {
return Ban{}, false
}
return *ban, true
}
// activeBan returns the ban in bans, a netblock's bans oldest first, that
// is active at now, or nil when none is. If several are, it returns the
// one that started last. Every ban is looked at, since a ban an admin adds
// to bans.json can start before the netblock's others and outlast them.
func activeBan(bans []Ban, now time.Time) *Ban {
for i := len(bans) - 1; i >= 0; i-- {
if bans[i].ActiveAt(now) {
return &bans[i]
}
}
return nil
}
// BanForLimit bans netblock at now for a broken limit, with notes, and
// returns the ban. A first ban lasts LimitBanDuration. A ban made within
// LimitBanRepeatWindow after the netblock's ban that ended last lasts
// repeatFactor times as long as that one. A ban that would be longer
// than MaxBanDuration is permanent instead. If a ban on netblock is still
// active, as when two of its requests break a limit at once, that ban is
// returned and no other is made. The ledger fills in the notes' Refused
// and EarlierBans itself.
func (l *Ledger) BanForLimit(netblock netip.Prefix, now time.Time, notes Notes) Ban {
l.mu.Lock()
defer l.mu.Unlock()
var last *Ban
bans, found := l.netblocks.Get(netblock)
if found {
active := activeBan(*bans, now)
if active != nil {
return *active
}
// No ban is active, so each has an end. A ban an admin adds to
// bans.json can start after another and end before it, so the
// ban that ended last is looked for among them all.
ended := slices.MaxFunc(*bans, func(a, b Ban) int {
return a.Expires.Compare(b.Expires)
})
last = &ended
// The netblock's first ban held counts the bans it had before that
// one, since dropped to make room, and each ban held adds one.
notes.EarlierBans = (*bans)[0].Notes.EarlierBans + len(*bans)
}
notes.Request = notes.Request.cut()
ban := Ban{
Netblock: netblock,
Start: now,
Expires: l.expiry(last, now),
Notes: notes,
}
l.add(ban)
l.made++
select {
case l.changed <- struct{}{}:
default: // a value is waiting already
}
return ban
}
// Bans returns the bans held on netblock, oldest first. It is not a
// request from netblock, and leaves when it was last seen unchanged.
func (l *Ledger) Bans(netblock netip.Prefix) []Ban {
l.mu.Lock()
defer l.mu.Unlock()
bans, found := l.netblocks.Peek(netblock)
if !found {
return nil
}
return slices.Clone(*bans)
}
// Made returns how many bans the ledger has made since the start; bans
// read from bans.json are not among them.
func (l *Ledger) Made() int {
l.mu.Lock()
defer l.mu.Unlock()
return l.made
}
// Count returns how many of the bans held are active at now, and how many
// are permanent.
func (l *Ledger) Count(now time.Time) (int, int) {
l.mu.Lock()
defer l.mu.Unlock()
active, permanent := 0, 0
for _, bans := range l.netblocks.Values() {
for _, ban := range *bans {
if ban.ActiveAt(now) {
active++
}
if ban.Permanent() {
permanent++
}
}
}
return active, permanent
}
// Snapshot returns every ban held, sorted by netblock, and each
// netblock's bans oldest first, as bans.json lists them.
func (l *Ledger) Snapshot() []Ban {
l.mu.Lock()
defer l.mu.Unlock()
held := make([]Ban, 0, l.held)
for _, bans := range l.netblocks.Values() {
held = append(held, *bans...)
}
slices.SortStableFunc(held, func(a, b Ban) int {
return a.Netblock.Compare(b.Netblock)
})
return held
}
// Load puts bans read from bans.json into the ledger, in place of the
// bans it holds, in the order they started, so that a netblock whose last
// ban started latest counts as the most recently seen. Each netblock is
// masked to its length, so that 203.0.113.9/24 is 203.0.113.0/24, and
// each text in the notes is cut to 256 bytes. Past MaxBans the earliest
// bans are dropped, as when they are made.
func (l *Ledger) Load(bans []Ban) {
bans = slices.Clone(bans)
slices.SortStableFunc(bans, func(a, b Ban) int {
return a.Start.Compare(b.Start)
})
l.mu.Lock()
defer l.mu.Unlock()
l.netblocks.Purge()
l.held = 0
l.v4Lengths, l.v6Lengths = nil, nil
for _, ban := range bans {
ban.Netblock = ban.Netblock.Masked()
ban.Notes.Request = ban.Notes.Request.cut()
l.add(ban)
}
}
// active returns the ban active at now on a netblock client is in, or
// nil.
func (l *Ledger) active(client netip.Addr, now time.Time) *Ban {
lengths := l.v6Lengths
if client.Is4() {
lengths = l.v4Lengths
}
for _, length := range lengths {
bans, found := l.netblocks.Get(netip.PrefixFrom(client, length).Masked())
if !found {
continue
}
ban := activeBan(*bans, now)
if ban != nil {
return ban
}
}
return nil
}
// add adds ban to its netblock's bans, after the last, and makes its
// netblock the most recently seen. With MaxBans held, it drops one first.
func (l *Ledger) add(ban Ban) {
if l.held == l.rules.MaxBans {
l.dropOne()
}
// dropOne can have dropped the netblock's last ban, and the netblock
// with it.
bans, found := l.netblocks.Get(ban.Netblock)
if !found {
bans = &[]Ban{}
l.netblocks.Add(ban.Netblock, bans)
}
*bans = append(*bans, ban)
l.held++
lengths := &l.v6Lengths
if ban.Netblock.Addr().Is4() {
lengths = &l.v4Lengths
}
if !slices.Contains(*lengths, ban.Netblock.Bits()) {
*lengths = append(*lengths, ban.Netblock.Bits())
}
}
// expiry returns when a ban for a broken limit made at now ends, or zero
// when it is permanent. last is the netblock's ban that ended last, or nil
// when it has none.
func (l *Ledger) expiry(last *Ban, now time.Time) time.Time {
length := l.rules.LimitBanDuration
if last != nil && now.Sub(last.Expires) <= l.rules.LimitBanRepeatWindow {
lastLength := last.Expires.Sub(last.Start)
// This is repeatFactor * lastLength > MaxBanDuration, written so
// that it cannot overflow.
if lastLength > l.rules.MaxBanDuration/repeatFactor {
return time.Time{}
}
length = repeatFactor * lastLength
}
if length > l.rules.MaxBanDuration {
return time.Time{}
}
return now.Add(length)
}
// dropOne drops the earliest ban of the netblock that has gone longest
// without a request, and the netblock with it if that was its only ban.
func (l *Ledger) dropOne() {
netblock, bans, _ := l.netblocks.GetOldest()
if len(*bans) == 1 {
l.netblocks.Remove(netblock)
} else {
*bans = slices.Delete(*bans, 0, 1)
}
l.held--
}
// cut returns r with each text cut to maxTextBytes and copied, so that
// the notes do not keep the rest of the request in memory.
func (r Request) cut() Request {
r.Method = cutText(r.Method)
r.Host = cutText(r.Host)
r.Path = cutText(r.Path)
r.UserAgent = cutText(r.UserAgent)
return r
}
// cutText returns a copy of the first maxTextBytes of text.
func cutText(text string) string {
return strings.Clone(text[:min(len(text), maxTextBytes)])
}
internal/bans/bans_test.go
+291
View File
@@ -0,0 +1,291 @@
package bans_test
import (
"net/netip"
"strings"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/bans"
)
const day = 24 * time.Hour
func TestRepeatsTripleUntilPermanent(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
now := midnight()
// Each ban is followed by another as soon as it ends: 1, 3, 9, 27 and
// 81 hours.
for i, hours := range []int{1, 3, 9, 27, 81} {
ban := ledger.BanForLimit(netblock, now, bans.Notes{})
length := time.Duration(hours) * time.Hour
if !ban.Expires.Equal(now.Add(length)) || ban.Notes.EarlierBans != i {
t.Fatalf("ban %d lasts %s with %d earlier bans, want %d hours and %d",
i+1, ban.Expires.Sub(now), ban.Notes.EarlierBans, hours, i)
}
now = ban.Expires
}
// The sixth would last 243 hours, more than seven days: it is
// permanent, and never ends.
ban := ledger.BanForLimit(netblock, now, bans.Notes{})
if !ban.Permanent() {
t.Fatalf("sixth ban ends at %s, want a permanent one", ban.Expires)
}
_, banned := ledger.Check(netblock.Addr(), now.Add(100*365*day))
if !banned {
t.Error("a permanent ban ended")
}
}
func TestRepeatWindowRunsOut(t *testing.T) {
t.Parallel()
for _, tc := range []struct {
name string
// gap is the time between the end of the first ban and the second.
gap time.Duration
want time.Duration
}{
{"broken again as the window ends", day, 3 * time.Hour},
{"broken again after the window", day + time.Nanosecond, time.Hour},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
first := ledger.BanForLimit(netblock, midnight(), bans.Notes{})
second := ledger.BanForLimit(netblock, first.Expires.Add(tc.gap), bans.Notes{})
if second.Expires.Sub(second.Start) != tc.want || second.Notes.EarlierBans != 1 {
t.Errorf("second ban lasts %s with %d earlier bans, want %s and 1",
second.Expires.Sub(second.Start), second.Notes.EarlierBans, tc.want)
}
})
}
}
func TestFirstBanLongerThanTheMaximumIsPermanent(t *testing.T) {
t.Parallel()
rules := defaultRules()
rules.LimitBanDuration = rules.MaxBanDuration + time.Hour
ledger := bans.New(rules)
ban := ledger.BanForLimit(netip.MustParsePrefix("203.0.113.9/32"), midnight(),
bans.Notes{})
if !ban.Permanent() {
t.Errorf("first ban ends at %s, want a permanent one", ban.Expires)
}
}
func TestLongestBanSetFarOffDoesNotOverflow(t *testing.T) {
t.Parallel()
// With bans of up to 100,000 days, the 14th ban in a row, of 3^13
// hours, is within the maximum, and three times as long would not fit
// in a time.Duration. The 15th is permanent.
rules := defaultRules()
rules.MaxBanDuration = 100000 * day
ledger := bans.New(rules)
netblock := netip.MustParsePrefix("203.0.113.9/32")
now := midnight()
for i := range 14 {
ban := ledger.BanForLimit(netblock, now, bans.Notes{})
if !ban.Expires.After(ban.Start) {
t.Fatalf("ban %d starts at %s and ends at %s", i+1, ban.Start, ban.Expires)
}
now = ban.Expires
}
ban := ledger.BanForLimit(netblock, now, bans.Notes{})
if !ban.Permanent() {
t.Errorf("15th ban ends at %s, want a permanent one", ban.Expires)
}
}
func TestBrokenLimitDuringABanMakesNoOther(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
first := ledger.BanForLimit(netblock, midnight(), bans.Notes{})
again := ledger.BanForLimit(netblock, midnight().Add(time.Minute), bans.Notes{})
if again != first || len(ledger.Bans(netblock)) != 1 {
t.Errorf("a limit broken during a ban gave %+v and %d bans, want %+v and 1",
again, len(ledger.Bans(netblock)), first)
}
}
func TestCheckRefusesWhileTheBanLastsAndCountsTheRefusals(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
ban := ledger.BanForLimit(netblock, midnight(), bans.Notes{Requests: 5})
for range 3 {
got, banned := ledger.Check(netblock.Addr(), ban.Expires.Add(-time.Nanosecond))
if !banned || got.Start != ban.Start {
t.Fatalf("check during the ban gives %+v and %t", got, banned)
}
}
_, banned := ledger.Check(netip.MustParseAddr("203.0.113.10"), midnight())
if banned {
t.Error("another netblock is banned")
}
_, banned = ledger.Check(netblock.Addr(), ban.Expires)
if banned {
t.Error("the ban did not end")
}
// The netblock's requests went from 5 to 8 with the three refused.
notes := ledger.Bans(netblock)[0].Notes
if notes.Refused != 3 || notes.Requests != 8 {
t.Errorf("the notes count %d refused requests of %d, want 3 of 8",
notes.Refused, notes.Requests)
}
}
func TestFindCountsNothing(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
ban := ledger.BanForLimit(netblock, midnight(), bans.Notes{Requests: 5})
got, banned := ledger.Find(netblock.Addr(), ban.Expires.Add(-time.Nanosecond))
if !banned || got != ban {
t.Errorf("find during the ban gives %+v and %t, want %+v", got, banned, ban)
}
_, banned = ledger.Find(netblock.Addr(), ban.Expires)
if banned {
t.Error("the ban did not end")
}
if notes := ledger.Bans(netblock)[0].Notes; notes != ban.Notes {
t.Errorf("the notes are %+v, want them unchanged, %+v", notes, ban.Notes)
}
}
func TestMaxBansDropsTheEarliestBanOfTheNetblockSeenLongestAgo(t *testing.T) {
t.Parallel()
rules := defaultRules()
rules.MaxBans = 3
ledger := bans.New(rules)
a := netip.MustParsePrefix("203.0.113.1/32")
b := netip.MustParsePrefix("203.0.113.2/32")
c := netip.MustParsePrefix("203.0.113.3/32")
d := netip.MustParsePrefix("2001:db8::/64")
now := midnight()
first := ledger.BanForLimit(a, now, bans.Notes{})
ledger.BanForLimit(b, now, bans.Notes{})
ledger.BanForLimit(c, now, bans.Notes{})
// A request from a makes b the netblock seen longest ago, and its ban
// goes to make room for d's.
ledger.Check(a.Addr(), now)
ledger.BanForLimit(d, now, bans.Notes{})
wantBans(t, ledger, map[netip.Prefix]int{a: 1, b: 0, c: 1, d: 1})
// a is banned again once its ban has ended; c, seen longest ago, goes.
ledger.BanForLimit(a, first.Expires, bans.Notes{})
wantBans(t, ledger, map[netip.Prefix]int{a: 2, c: 0, d: 1})
// With d seen since, a is seen longest ago, and its earlier ban goes
// first.
ledger.Check(d.Addr(), first.Expires)
ledger.BanForLimit(b, first.Expires, bans.Notes{})
wantBans(t, ledger, map[netip.Prefix]int{a: 1, b: 1, d: 1})
if !ledger.Bans(a)[0].Start.Equal(first.Expires) {
t.Errorf("a kept its ban of %s, want the later one", ledger.Bans(a)[0].Start)
}
}
func TestFullLedgerDropsTheEarlierBanOfTheNetblockBannedAgain(t *testing.T) {
t.Parallel()
// With room for one ban, the netblock's ended ban goes to make room for
// its new one, whose notes still count it.
rules := defaultRules()
rules.MaxBans = 1
ledger := bans.New(rules)
netblock := netip.MustParsePrefix("203.0.113.9/32")
first := ledger.BanForLimit(netblock, midnight(), bans.Notes{})
second := ledger.BanForLimit(netblock, first.Expires, bans.Notes{})
held := ledger.Bans(netblock)
if len(held) != 1 || held[0] != second || held[0].Notes.EarlierBans != 1 {
t.Errorf("the ledger holds %+v, want only the second ban, with 1 earlier ban",
held)
}
}
func TestRequestTextsAreCutTo256Bytes(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
long := strings.Repeat("a", 300)
request := bans.Request{
Time: midnight(), Method: long, Host: long, Path: long, Status: 403, UserAgent: long,
}
ban := ledger.BanForLimit(netblock, midnight(), bans.Notes{Request: request})
cut := long[:256]
want := bans.Request{
Time: midnight(), Method: cut, Host: cut, Path: cut, Status: 403, UserAgent: cut,
}
if ban.Notes.Request != want || ledger.Bans(netblock)[0].Notes.Request != want {
t.Errorf("the notes keep %+v, want each text cut to 256 bytes", ban.Notes.Request)
}
}
// defaultRules are the rules at the settings' defaults.
func defaultRules() bans.Rules {
return bans.Rules{
LimitBanDuration: time.Hour,
LimitBanRepeatWindow: day,
MaxBanDuration: 7 * day,
MaxBans: 5000,
}
}
// midnight is when the tests' first bans are made.
func midnight() time.Time {
return time.Date(2026, 10, 6, 0, 0, 0, 0, time.UTC)
}
// wantBans checks how many bans the ledger holds on each netblock.
func wantBans(t *testing.T, ledger *bans.Ledger, want map[netip.Prefix]int) {
t.Helper()
for netblock, count := range want {
got := len(ledger.Bans(netblock))
if got != count {
t.Errorf("%s has %d bans, want %d", netblock, got, count)
}
}
}
internal/bans/snapshot_test.go
+297
View File
@@ -0,0 +1,297 @@
package bans_test
import (
"net/netip"
"slices"
"strings"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/bans"
)
func TestChangedAfterABanIsMade(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
wantChanged(t, ledger, false)
ledger.BanForLimit(netblock, midnight(), bans.Notes{})
wantChanged(t, ledger, true)
// A limit broken during the ban makes no other, and a refusal changes
// only the counts in the notes, which wait for the interval's write.
ledger.BanForLimit(netblock, midnight().Add(time.Minute), bans.Notes{})
ledger.Check(netblock.Addr(), midnight().Add(time.Minute))
wantChanged(t, ledger, false)
// Two bans before the value is read leave one.
ledger.BanForLimit(netip.MustParsePrefix("203.0.113.10/32"), midnight(), bans.Notes{})
ledger.BanForLimit(netip.MustParsePrefix("203.0.113.11/32"), midnight(), bans.Notes{})
wantChanged(t, ledger, true)
wantChanged(t, ledger, false)
}
func TestSnapshotListsEveryBanByNetblock(t *testing.T) {
t.Parallel()
ledger := bans.New(defaultRules())
v6 := netip.MustParsePrefix("2001:db8::/64")
high := netip.MustParsePrefix("203.0.113.10/32")
low := netip.MustParsePrefix("203.0.113.9/32")
first := ledger.BanForLimit(v6, midnight(), bans.Notes{})
ledger.BanForLimit(high, midnight(), bans.Notes{})
ledger.BanForLimit(low, midnight(), bans.Notes{})
ledger.BanForLimit(v6, first.Expires, bans.Notes{})
snapshot := ledger.Snapshot()
got := make([]string, 0, len(snapshot))
for _, ban := range snapshot {
got = append(got, ban.Netblock.String()+" "+ban.Start.Format(time.Kitchen))
}
want := []string{
"203.0.113.9/32 12:00AM", "203.0.113.10/32 12:00AM",
"2001:db8::/64 12:00AM", "2001:db8::/64 1:00AM",
}
if !slices.Equal(got, want) {
t.Errorf("snapshot %v, want %v", got, want)
}
}
func TestLoadedBansCarryOn(t *testing.T) {
t.Parallel()
before := bans.New(defaultRules())
netblock := netip.MustParsePrefix("203.0.113.9/32")
ban := before.BanForLimit(netblock, midnight(), bans.Notes{Limit: 1})
// Loaded into a new ledger, as across a restart, the ban still refuses
// while it lasts, and once it has ended a broken limit bans for three
// times as long, with the loaded ban counted among the earlier ones.
after := bans.New(defaultRules())
after.Load(before.Snapshot())
_, banned := after.Check(netblock.Addr(), ban.Expires.Add(-time.Second))
if !banned {
t.Error("the loaded ban does not refuse")
}
again := after.BanForLimit(netblock, ban.Expires, bans.Notes{})
if again.Expires.Sub(again.Start) != 3*time.Hour || again.Notes.EarlierBans != 1 {
t.Errorf("the next ban lasts %s with %d earlier bans, want 3h and 1",
again.Expires.Sub(again.Start), again.Notes.EarlierBans)
}
}
func TestLoadedBanRefusesEveryClientInItsNetblock(t *testing.T) {
t.Parallel()
// Two entries as an admin might write them, with addresses not masked
// to their lengths, the IPv6 one shorter than the /64 an IPv6 client's
// ban covers, beside a ban the ledger makes on one IPv4 address.
ledger := bans.New(defaultRules())
ledger.Load([]bans.Ban{
{Netblock: netip.MustParsePrefix("203.0.113.9/24"), Start: midnight()},
{Netblock: netip.MustParsePrefix("2001:db8::1/48"), Start: midnight()},
})
ledger.BanForLimit(netip.MustParsePrefix("198.51.100.7/32"), midnight(), bans.Notes{})
for client, want := range map[string]bool{
"203.0.113.0": true,
"203.0.113.200": true,
"203.0.114.1": false,
"2001:db8:0:5::1": true,
"2001:db8:1::1": false,
"198.51.100.7": true,
"198.51.100.8": false,
} {
_, banned := ledger.Check(netip.MustParseAddr(client), midnight())
if banned != want {
t.Errorf("%s is refused: %t, want %t", client, banned, want)
}
}
// The loaded netblocks are written back masked.
snapshot := ledger.Snapshot()
got := make([]string, 0, len(snapshot))
for _, ban := range snapshot {
got = append(got, ban.Netblock.String())
}
want := []string{"198.51.100.7/32", "203.0.113.0/24", "2001:db8::/48"}
if !slices.Equal(got, want) {
t.Errorf("the ledger holds bans on %v, want %v", got, want)
}
}
func TestPermanentBanStartedBeforeAnEndedOneRefuses(t *testing.T) {
t.Parallel()
// As when an admin adds a permanent ban to bans.json with a start
// before that of the netblock's ban that has ended.
netblock := netip.MustParsePrefix("203.0.113.0/24")
permanent := bans.Ban{Netblock: netblock, Start: midnight().Add(-time.Hour)}
ended := bans.Ban{
Netblock: netblock,
Start: midnight(),
Expires: midnight().Add(time.Hour),
}
ledger := bans.New(defaultRules())
ledger.Load([]bans.Ban{permanent, ended})
now := midnight().Add(2 * time.Hour)
client := netip.MustParseAddr("203.0.113.9")
ban, banned := ledger.Find(client, now)
if !banned || !ban.Permanent() {
t.Errorf("find gives %+v and %t, want the permanent ban", ban, banned)
}
ban, banned = ledger.Check(client, now)
if !banned || !ban.Permanent() {
t.Errorf("the client is refused: %t, under %+v, want under the permanent ban",
banned, ban)
}
// A limit broken now makes no shorter ban over the permanent one.
ban = ledger.BanForLimit(netblock, now, bans.Notes{})
if !ban.Permanent() || len(ledger.Bans(netblock)) != 2 {
t.Errorf("a broken limit returned %+v and left the netblock %d bans, "+
"want the permanent ban and 2", ban, len(ledger.Bans(netblock)))
}
}
func TestNextBanWorkedOutFromTheBanThatEndedLast(t *testing.T) {
t.Parallel()
// A 9-hour ban smallwebwaf made, the third in a row, and an admin's
// 1-hour ban added to bans.json over it, with no notes.
netblock := netip.MustParsePrefix("203.0.113.9/32")
nineHours := bans.Ban{
Netblock: netblock,
Start: midnight(),
Expires: midnight().Add(9 * time.Hour),
Notes: bans.Notes{EarlierBans: 2},
}
admins := bans.Ban{
Netblock: netblock,
Start: midnight().Add(time.Hour),
Expires: midnight().Add(2 * time.Hour),
}
ledger := bans.New(defaultRules())
ledger.Load([]bans.Ban{nineHours, admins})
// Once both have ended, a limit broken within the repeat window bans
// for three times the 9 hours, and the notes count the two bans
// before the 9-hour one, it, and the admin's.
ban := ledger.BanForLimit(netblock, nineHours.Expires.Add(time.Hour), bans.Notes{})
if ban.Expires.Sub(ban.Start) != 27*time.Hour || ban.Notes.EarlierBans != 4 {
t.Errorf("the next ban lasts %s with %d earlier bans, want 27h and 4",
ban.Expires.Sub(ban.Start), ban.Notes.EarlierBans)
}
}
func TestLoadKeepsAtMostMaxBansDroppingTheEarliest(t *testing.T) {
t.Parallel()
// bans.json lists the bans by netblock, not in the order they began.
later := bans.Ban{Netblock: netip.MustParsePrefix("203.0.113.1/32"), Start: midnight()}
earlier := bans.Ban{
Netblock: netip.MustParsePrefix("203.0.113.2/32"),
Start: midnight().Add(-time.Hour),
}
rules := defaultRules()
rules.MaxBans = 1
ledger := bans.New(rules)
ledger.Load([]bans.Ban{later, earlier})
held := ledger.Snapshot()
if len(held) != 1 || held[0] != later {
t.Errorf("the ledger holds %+v, want only the ban that began later", held)
}
}
func TestLoadReplacesTheBansHeld(t *testing.T) {
t.Parallel()
// Room for three bans, so that the second load, were it added to the
// two bans held, would drop none of them to make room.
rules := defaultRules()
rules.MaxBans = 3
ledger := bans.New(rules)
kept := bans.Ban{Netblock: netip.MustParsePrefix("2001:db8::/64"), Start: midnight()}
ledger.Load([]bans.Ban{
{Netblock: netip.MustParsePrefix("203.0.113.0/24"), Start: midnight()},
kept,
})
// Loaded again without the first ban, as when an admin's edit of
// bans.json is taken in, that ban is lifted.
ledger.Load([]bans.Ban{kept})
_, banned := ledger.Check(netip.MustParseAddr("203.0.113.9"), midnight())
if banned {
t.Error("a ban left out of the second load still refuses")
}
// The ledger holds one ban, so it makes two more without dropping any.
first := ledger.BanForLimit(netip.MustParsePrefix("198.51.100.7/32"), midnight(),
bans.Notes{})
second := ledger.BanForLimit(netip.MustParsePrefix("198.51.100.8/32"), midnight(),
bans.Notes{})
want := []bans.Ban{first, second, kept}
if got := ledger.Snapshot(); !slices.Equal(got, want) {
t.Errorf("the ledger holds %+v, want %+v", got, want)
}
}
func TestLoadCutsTheTextsTo256Bytes(t *testing.T) {
t.Parallel()
long := strings.Repeat("a", 300)
ban := bans.Ban{
Netblock: netip.MustParsePrefix("203.0.113.9/32"),
Start: midnight(),
Notes: bans.Notes{Request: bans.Request{
Method: long, Host: long, Path: long, UserAgent: long,
}},
}
ledger := bans.New(defaultRules())
ledger.Load([]bans.Ban{ban})
cut := long[:256]
want := bans.Request{Method: cut, Host: cut, Path: cut, UserAgent: cut}
got := ledger.Snapshot()[0].Notes.Request
if got != want {
t.Errorf("the notes keep %+v, want each text cut to 256 bytes", got)
}
}
// wantChanged checks whether the ledger's Changed has a value to read.
func wantChanged(t *testing.T, ledger *bans.Ledger, want bool) {
t.Helper()
got := false
select {
case <-ledger.Changed():
got = true
default:
}
if got != want {
t.Errorf("Changed has a value: %t, want %t", got, want)
}
}
internal/config/config.go
+419 -4
View File
@@ -9,11 +9,16 @@ import (
"log/slog"
"math"
"net"
"net/http"
"net/netip"
"net/url"
"os"
"path/filepath"
"slices"
"strconv"
"strings"
"time"
"unicode/utf8"
)
// Config is smallwebwaf's settings. A timeout, size or rate limit of zero
@@ -23,12 +28,28 @@ type Config struct {
ListenAddr string
// UpstreamURL is the app (SWWAF_UPSTREAM_URL).
UpstreamURL *url.URL
// InstanceName is the name each request log line gives as instance
// (SWWAF_INSTANCE_NAME), by default the host's name, which docker sets
// to the first 12 characters of the container's id.
InstanceName string
// Observe is true in observe mode, when SWWAF_MODE is observe rather
// than enforce: a request that SWWAF_DENY_NETS, a ban, the country
// lists or a rate limit would refuse is passed to the app instead, and
// no ban is made.
Observe bool
// TrustedProxies are the netblocks whose X-Forwarded-For is
// believed (SWWAF_TRUSTED_PROXIES).
TrustedProxies []netip.Prefix
// ClientRequestTimeout bounds reading the whole request from the
// client (SWWAF_CLIENT_REQUEST_TIMEOUT).
ClientRequestTimeout time.Duration
// ClientRequestHeaderMaxBytes is the largest request line and headers
// a client may send (SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES). It is
// never off, and always more than 4K.
ClientRequestHeaderMaxBytes int64
// ClientIdleTimeout bounds how long a kept-open client connection
// may wait for its next request (SWWAF_CLIENT_IDLE_TIMEOUT).
ClientIdleTimeout time.Duration
// ClientResponseTimeout bounds writing the whole response to the
// client (SWWAF_CLIENT_RESPONSE_TIMEOUT).
ClientResponseTimeout time.Duration
@@ -44,6 +65,14 @@ type Config struct {
// ResponseMaxBytes is the largest response body
// (SWWAF_RESPONSE_MAX_BYTES).
ResponseMaxBytes int64
// AllowNets are the netblocks whose clients skip every check
// (SWWAF_ALLOW_NETS). RateLimitExemptNets are those whose clients the
// rate limits neither count nor refuse (SWWAF_RATE_LIMIT_EXEMPT_NETS).
// DenyNets are those whose clients are always refused
// (SWWAF_DENY_NETS).
AllowNets []netip.Prefix
RateLimitExemptNets []netip.Prefix
DenyNets []netip.Prefix
// RateLimitPerMinute, RateLimitPerHour and RateLimitPerDay are the
// most requests a client may make in a minute, an hour and a day
// (SWWAF_RATE_LIMIT_PER_MINUTE, SWWAF_RATE_LIMIT_PER_HOUR and
@@ -51,6 +80,53 @@ type Config struct {
RateLimitPerMinute int64
RateLimitPerHour int64
RateLimitPerDay int64
// RateLimitExemptPaths are the path prefixes whose requests the rate
// limits neither count nor refuse (SWWAF_RATE_LIMIT_EXEMPT_PATHS).
// Each starts with /.
RateLimitExemptPaths []string
// DeniedCountries are the countries whose clients are refused
// (SWWAF_DENIED_COUNTRIES). ExclusivelyAllowedCountries, when not
// empty, are the only countries whose clients are let through
// (SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES). Both hold two-letter codes in
// capitals, as GeoJS gives them.
DeniedCountries []string
ExclusivelyAllowedCountries []string
// BanResponse is the status a refused client is answered with, 403
// or 429, or 0 to close the connection without an answer
// (SWWAF_BAN_RESPONSE). It answers a banned client, a request that
// breaks a rate limit, SWWAF_DENY_NETS and the country lists.
BanResponse int
// LimitBanDuration is the ban for a first broken rate limit
// (SWWAF_LIMIT_BAN_DURATION). A limit broken again within
// LimitBanRepeatWindow after the last ban ended bans for three times
// as long as that ban (SWWAF_LIMIT_BAN_REPEAT_WINDOW), and a ban that
// would be longer than MaxBanDuration is permanent instead
// (SWWAF_MAX_BAN_DURATION). None of them can be off.
LimitBanDuration time.Duration
LimitBanRepeatWindow time.Duration
MaxBanDuration time.Duration
// MaxBans is the most bans held (SWWAF_MAX_BANS).
MaxBans int
// BanScopeV4Prefix is the length of the netblock around an IPv4
// client that a ban covers (SWWAF_BAN_SCOPE_V4_PREFIX).
BanScopeV4Prefix int
// StateDir is the directory of the state files, an absolute path
// (SWWAF_STATE_DIR). bans.json is written StateWriteDelay after a ban
// is made (SWWAF_STATE_WRITE_DELAY), and every state file every
// StateCounterInterval (SWWAF_STATE_COUNTER_INTERVAL). Neither can be
// off.
StateDir string
StateWriteDelay time.Duration
StateCounterInterval time.Duration
// LogRequestHeaders are the request headers whose values the request
// log gives, in lower case (SWWAF_LOG_REQUEST_HEADERS).
LogRequestHeaders []string
// MetricsToken is the bearer token a scraper sends for the metrics
// (SWWAF_METRICS_TOKEN), "" while it is unset and the metrics are off.
// MetricsTopN is how many countries get series of their own in the
// metrics (SWWAF_METRICS_TOP_N).
MetricsToken string
MetricsTopN int
// settings are the values read, as given or by default, for the
// log line at start.
@@ -66,6 +142,11 @@ const (
kibibyte = 1 << 10
mebibyte = 1 << 20
gibibyte = 1 << 30
ipv4Bits = 32
// minTokenLength is the fewest characters a token may have.
minTokenLength = 32
// masked is what the log shows for a token that is set.
masked = "********"
)
var (
@@ -84,6 +165,28 @@ var (
errNotUpstreamURL = errors.New(
"is not a URL with only a scheme, a host and an optional port, " +
"such as http://127.0.0.1:8081")
errNotCountry = errors.New(
"is not a two-letter country code such as de or kp")
errNotHeaderName = errors.New(
"is not a header name such as accept-language")
errHeaderTakenOut = errors.New(
"is taken out of every request by Go's HTTP server, so it can never " +
"be logged")
errOnBothLists = errors.New("is in SWWAF_DENIED_COUNTRIES too")
errNotOver4K = errors.New("is not a size of more than 4K, such as 32K")
errNotDurationAboveZero = errors.New(
"is not a duration above zero, such as 1h or 7d")
errNotNumberAboveZero = errors.New(
"is not a whole number above zero, such as 5000")
errNotBanResponse = errors.New("is not 403, 429 or close")
errNotV4Prefix = errors.New(
"is not the length of an IPv4 netblock, from 0 to 32, such as 24")
errNotAbsolutePath = errors.New(
"is not an absolute path, such as /var/lib/smallwebwaf")
errShortToken = errors.New("is shorter than 32 characters")
errNotMode = errors.New("is not enforce or observe")
errNotPathPrefix = errors.New(
"is not a path prefix starting with /, such as /assets/")
)
// FromEnvironment reads the settings with lookupEnv, normally
@@ -91,19 +194,52 @@ var (
// that is set but invalid is an error that names it.
func FromEnvironment(lookupEnv func(string) (string, bool)) (*Config, error) {
env := &environment{lookupEnv: lookupEnv}
hostname, _ := os.Hostname() // "" when the host has no name to give
cfg := &Config{
ListenAddr: env.address("SWWAF_LISTEN_ADDR", ":8080"),
UpstreamURL: env.appURL("SWWAF_UPSTREAM_URL", "http://127.0.0.1:8081"),
TrustedProxies: env.netblocks("SWWAF_TRUSTED_PROXIES", privateRanges),
ClientRequestTimeout: env.duration("SWWAF_CLIENT_REQUEST_TIMEOUT", "60s"),
ListenAddr: env.address("SWWAF_LISTEN_ADDR", ":8080"),
UpstreamURL: env.appURL("SWWAF_UPSTREAM_URL", "http://127.0.0.1:8081"),
InstanceName: env.value("SWWAF_INSTANCE_NAME", hostname),
Observe: env.observe("SWWAF_MODE", "enforce"),
TrustedProxies: env.netblocks("SWWAF_TRUSTED_PROXIES", privateRanges),
ClientRequestTimeout: env.duration("SWWAF_CLIENT_REQUEST_TIMEOUT", "60s"),
ClientRequestHeaderMaxBytes: env.headerSize(
"SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES", "32K"),
ClientIdleTimeout: env.duration("SWWAF_CLIENT_IDLE_TIMEOUT", "120s"),
ClientResponseTimeout: env.duration("SWWAF_CLIENT_RESPONSE_TIMEOUT", "30m"),
UpstreamRequestTimeout: env.duration("SWWAF_UPSTREAM_REQUEST_TIMEOUT", "60s"),
UpstreamResponseTimeout: env.duration("SWWAF_UPSTREAM_RESPONSE_TIMEOUT", "30m"),
RequestMaxBytes: env.size("SWWAF_REQUEST_MAX_BYTES", "100M"),
ResponseMaxBytes: env.size("SWWAF_RESPONSE_MAX_BYTES", "5G"),
AllowNets: env.netblocks("SWWAF_ALLOW_NETS", ""),
RateLimitExemptNets: env.netblocks("SWWAF_RATE_LIMIT_EXEMPT_NETS", ""),
DenyNets: env.netblocks("SWWAF_DENY_NETS", ""),
RateLimitPerMinute: env.count("SWWAF_RATE_LIMIT_PER_MINUTE", "1000"),
RateLimitPerHour: env.count("SWWAF_RATE_LIMIT_PER_HOUR", "10000"),
RateLimitPerDay: env.count("SWWAF_RATE_LIMIT_PER_DAY", "50000"),
RateLimitExemptPaths: env.pathPrefixes("SWWAF_RATE_LIMIT_EXEMPT_PATHS", ""),
DeniedCountries: env.countries("SWWAF_DENIED_COUNTRIES", ""),
ExclusivelyAllowedCountries: env.countries(
"SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES", ""),
BanResponse: env.banResponse("SWWAF_BAN_RESPONSE", "403"),
LimitBanDuration: env.durationNotOff("SWWAF_LIMIT_BAN_DURATION", "1h"),
LimitBanRepeatWindow: env.durationNotOff("SWWAF_LIMIT_BAN_REPEAT_WINDOW", "24h"),
MaxBanDuration: env.durationNotOff("SWWAF_MAX_BAN_DURATION", "7d"),
MaxBans: env.numberNotOff("SWWAF_MAX_BANS", "5000"),
BanScopeV4Prefix: env.v4Prefix("SWWAF_BAN_SCOPE_V4_PREFIX", "32"),
StateDir: env.absolutePath("SWWAF_STATE_DIR", "/var/lib/smallwebwaf"),
StateWriteDelay: env.durationNotOff("SWWAF_STATE_WRITE_DELAY", "10s"),
StateCounterInterval: env.durationNotOff("SWWAF_STATE_COUNTER_INTERVAL", "15m"),
LogRequestHeaders: env.headerNames("SWWAF_LOG_REQUEST_HEADERS",
"accept,accept-language,accept-encoding,content-type,origin,range"),
MetricsToken: env.token("SWWAF_METRICS_TOKEN"),
MetricsTopN: env.numberNotOff("SWWAF_METRICS_TOP_N", "50"),
}
for _, country := range cfg.ExclusivelyAllowedCountries {
if slices.Contains(cfg.DeniedCountries, country) {
env.check("SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES",
fmt.Errorf("%q %w", country, errOnBothLists))
}
}
if env.err != nil {
@@ -169,6 +305,17 @@ func (e *environment) appURL(name, defaultValue string) *url.URL {
return upstream
}
// observe reads the setting that is the mode, enforce or observe, and
// reports whether it is observe.
func (e *environment) observe(name, defaultValue string) bool {
mode := e.value(name, defaultValue)
if mode != "enforce" && mode != "observe" {
e.check(name, fmt.Errorf("%q %w", mode, errNotMode))
}
return mode == "observe"
}
// netblocks reads a setting that is a list of netblocks.
func (e *environment) netblocks(name, defaultValue string) []netip.Prefix {
netblocks, err := parseNetblocks(e.value(name, defaultValue))
@@ -193,6 +340,15 @@ func (e *environment) size(name, defaultValue string) int64 {
return size
}
// headerSize reads the setting that is the largest request line and
// headers.
func (e *environment) headerSize(name, defaultValue string) int64 {
size, err := parseHeaderSize(e.value(name, defaultValue))
e.check(name, err)
return size
}
// count reads a setting that is a number of requests.
func (e *environment) count(name, defaultValue string) int64 {
count, err := parseCount(e.value(name, defaultValue))
@@ -201,6 +357,95 @@ func (e *environment) count(name, defaultValue string) int64 {
return count
}
// pathPrefixes reads a setting that is a list of path prefixes.
func (e *environment) pathPrefixes(name, defaultValue string) []string {
prefixes, err := parsePathPrefixes(e.value(name, defaultValue))
e.check(name, err)
return prefixes
}
// countries reads a setting that is a list of countries.
func (e *environment) countries(name, defaultValue string) []string {
countries, err := parseCountries(e.value(name, defaultValue))
e.check(name, err)
return countries
}
// headerNames reads a setting that is a list of header names, and
// returns them in lower case.
func (e *environment) headerNames(name, defaultValue string) []string {
headers, err := parseHeaderNames(e.value(name, defaultValue))
e.check(name, err)
return headers
}
// durationNotOff reads a setting that is a duration and, unlike a
// timeout, cannot be off.
func (e *environment) durationNotOff(name, defaultValue string) time.Duration {
duration, err := parseDurationNotOff(e.value(name, defaultValue))
e.check(name, err)
return duration
}
// numberNotOff reads a setting that is a whole number above zero, which
// cannot be off.
func (e *environment) numberNotOff(name, defaultValue string) int {
number, err := parseNumberNotOff(e.value(name, defaultValue))
e.check(name, err)
return number
}
// banResponse reads a setting that is how a refused client is answered.
func (e *environment) banResponse(name, defaultValue string) int {
status, err := parseBanResponse(e.value(name, defaultValue))
e.check(name, err)
return status
}
// v4Prefix reads a setting that is the length of an IPv4 netblock.
func (e *environment) v4Prefix(name, defaultValue string) int {
length, err := parseV4Prefix(e.value(name, defaultValue))
e.check(name, err)
return length
}
// absolutePath reads a setting that is an absolute path.
func (e *environment) absolutePath(name, defaultValue string) string {
path := e.value(name, defaultValue)
if !filepath.IsAbs(path) {
e.check(name, fmt.Errorf("%q %w", path, errNotAbsolutePath))
}
return path
}
// token reads a setting that is a bearer token. Unset, it is "", which
// switches off what it guards; set, it must be at least minTokenLength
// characters. Neither the log nor an error shows its value.
func (e *environment) token(name string) string {
value, set := e.lookupEnv(name)
if !set {
e.settings = append(e.settings, slog.String(name, ""))
return ""
}
e.settings = append(e.settings, slog.String(name, masked))
if utf8.RuneCountInString(value) < minTokenLength {
e.check(name, errShortToken)
}
return value
}
// parseDuration reads a duration in Go's syntax, such as 90s or 15m, a
// whole number of days such as 7d, or off.
func parseDuration(value string) (time.Duration, error) {
@@ -256,6 +501,19 @@ func parseSize(value string) (int64, error) {
return n * unit, nil
}
// parseHeaderSize reads the largest request line and headers: a size as
// parseSize reads it, but more than 4K and never off. Go's server reads 4K
// past the limit it is given before it refuses, so proxy.New gives it this
// size less 4K, which must leave a limit.
func parseHeaderSize(value string) (int64, error) {
size, err := parseSize(value)
if err != nil || size <= 4*kibibyte {
return 0, fmt.Errorf("%q %w", value, errNotOver4K)
}
return size, nil
}
// splitUnit splits a size into its number and the bytes its suffix
// stands for.
func splitUnit(value string) (string, int64) {
@@ -289,6 +547,52 @@ func parseCount(value string) (int64, error) {
return n, nil
}
// parseDurationNotOff reads a duration above zero, as parseDuration does,
// but not off.
func parseDurationNotOff(value string) (time.Duration, error) {
duration, err := parseDuration(value)
if err != nil || duration == 0 {
return 0, fmt.Errorf("%q %w", value, errNotDurationAboveZero)
}
return duration, nil
}
// parseNumberNotOff reads a whole number above zero.
func parseNumberNotOff(value string) (int, error) {
n, err := strconv.Atoi(value)
if err != nil || n <= 0 {
return 0, fmt.Errorf("%q %w", value, errNotNumberAboveZero)
}
return n, nil
}
// parseBanResponse reads how a refused client is answered: 403, 429, or
// close, which is 0.
func parseBanResponse(value string) (int, error) {
switch value {
case "403":
return http.StatusForbidden, nil
case "429":
return http.StatusTooManyRequests, nil
case "close":
return 0, nil
default:
return 0, fmt.Errorf("%q %w", value, errNotBanResponse)
}
}
// parseV4Prefix reads the length of an IPv4 netblock, from 0 to 32.
func parseV4Prefix(value string) (int, error) {
n, err := strconv.Atoi(value)
if err != nil || n < 0 || n > ipv4Bits {
return 0, fmt.Errorf("%q %w", value, errNotV4Prefix)
}
return n, nil
}
// parseList splits a comma-separated list and trims the spaces around
// each item. An empty value is an empty list.
func parseList(value string) ([]string, error) {
@@ -348,6 +652,117 @@ func parseNetblock(value string) (netip.Prefix, error) {
return netip.PrefixFrom(addr, addr.BitLen()), nil
}
// parsePathPrefixes reads a comma-separated list of path prefixes, each
// starting with /.
func parsePathPrefixes(value string) ([]string, error) {
prefixes, err := parseList(value)
if err != nil {
return nil, err
}
for _, prefix := range prefixes {
if !strings.HasPrefix(prefix, "/") {
return nil, fmt.Errorf("%q %w", prefix, errNotPathPrefix)
}
}
return prefixes, nil
}
// countryCodes are the two-letter codes ISO 3166-1 assigns today, and XK,
// the code in common use for Kosovo. golang.org/x/text/language cannot
// check them: it also takes withdrawn codes such as su, and reserved ones
// such as ac, as countries.
const countryCodes = `
AD AE AF AG AI AL AM AO AQ AR AS AT AU AW AX AZ
BA BB BD BE BF BG BH BI BJ BL BM BN BO BQ BR BS BT BV BW BY BZ
CA CC CD CF CG CH CI CK CL CM CN CO CR CU CV CW CX CY CZ
DE DJ DK DM DO DZ
EC EE EG EH ER ES ET
FI FJ FK FM FO FR
GA GB GD GE GF GG GH GI GL GM GN GP GQ GR GS GT GU GW GY
HK HM HN HR HT HU
ID IE IL IM IN IO IQ IR IS IT
JE JM JO JP
KE KG KH KI KM KN KP KR KW KY KZ
LA LB LC LI LK LR LS LT LU LV LY
MA MC MD ME MF MG MH MK ML MM MN MO MP MQ MR MS MT MU MV MW MX MY MZ
NA NC NE NF NG NI NL NO NP NR NU NZ
OM
PA PE PF PG PH PK PL PM PN PR PS PT PW PY
QA
RE RO RS RU RW
SA SB SC SD SE SG SH SI SJ SK SL SM SN SO SR SS ST SV SX SY SZ
TC TD TF TG TH TJ TK TL TM TN TO TR TT TV TW TZ
UA UG UM US UY UZ
VA VC VE VG VI VN VU
WF WS
XK
YE YT
ZA ZM ZW
`
// parseCountries reads a comma-separated list of country codes in either
// case, and returns them in capitals.
func parseCountries(value string) ([]string, error) {
items, err := parseList(value)
if err != nil {
return nil, err
}
known := strings.Fields(countryCodes)
countries := make([]string, 0, len(items))
for _, item := range items {
country := strings.ToUpper(item)
if !slices.Contains(known, country) {
return nil, fmt.Errorf("%q %w", item, errNotCountry)
}
countries = append(countries, country)
}
return countries, nil
}
// headerNameChars are the characters RFC 9110 allows in a header name:
// letters, digits and these marks.
const headerNameChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" +
"0123456789!#$%&'*+-.^_`|~"
// parseHeaderNames reads a comma-separated list of header names in either
// case, and returns them in lower case. Host and Transfer-Encoding are
// refused: Go's HTTP server takes them out of the request's headers.
func parseHeaderNames(value string) ([]string, error) {
items, err := parseList(value)
if err != nil {
return nil, err
}
headers := make([]string, 0, len(items))
for _, item := range items {
for _, char := range item {
if !strings.ContainsRune(headerNameChars, char) {
return nil, fmt.Errorf("%q %w", item, errNotHeaderName)
}
}
header := strings.ToLower(item)
switch header {
case "host":
return nil, fmt.Errorf("%q %w; the request's host is the field host",
item, errHeaderTakenOut)
case "transfer-encoding":
return nil, fmt.Errorf("%q %w", item, errHeaderTakenOut)
}
headers = append(headers, header)
}
return headers, nil
}
// parseListenAddr checks an address to listen on: an optional host and a
// port number.
func parseListenAddr(value string) (string, error) {
internal/config/config_test.go
+370 -30
View File
@@ -6,6 +6,7 @@ import (
"log/slog"
"maps"
"net/netip"
"os"
"slices"
"strings"
"testing"
@@ -18,18 +19,47 @@ import (
const (
listenAddr = "SWWAF_LISTEN_ADDR"
upstreamURL = "SWWAF_UPSTREAM_URL"
mode = "SWWAF_MODE"
trustedProxies = "SWWAF_TRUSTED_PROXIES"
clientRequestTimeout = "SWWAF_CLIENT_REQUEST_TIMEOUT"
clientHeaderMaxBytes = "SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES"
clientIdleTimeout = "SWWAF_CLIENT_IDLE_TIMEOUT"
clientResponseTimeout = "SWWAF_CLIENT_RESPONSE_TIMEOUT"
upstreamRequestTimeout = "SWWAF_UPSTREAM_REQUEST_TIMEOUT"
upstreamResponseTimeout = "SWWAF_UPSTREAM_RESPONSE_TIMEOUT"
requestMaxBytes = "SWWAF_REQUEST_MAX_BYTES"
responseMaxBytes = "SWWAF_RESPONSE_MAX_BYTES"
allowNets = "SWWAF_ALLOW_NETS"
rateLimitExemptNets = "SWWAF_RATE_LIMIT_EXEMPT_NETS"
denyNets = "SWWAF_DENY_NETS"
rateLimitPerMinute = "SWWAF_RATE_LIMIT_PER_MINUTE"
rateLimitPerHour = "SWWAF_RATE_LIMIT_PER_HOUR"
rateLimitPerDay = "SWWAF_RATE_LIMIT_PER_DAY"
rateLimitExemptPaths = "SWWAF_RATE_LIMIT_EXEMPT_PATHS"
deniedCountries = "SWWAF_DENIED_COUNTRIES"
allowedCountries = "SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES"
banResponse = "SWWAF_BAN_RESPONSE"
limitBanDuration = "SWWAF_LIMIT_BAN_DURATION"
limitBanRepeatWindow = "SWWAF_LIMIT_BAN_REPEAT_WINDOW"
maxBanDuration = "SWWAF_MAX_BAN_DURATION"
maxBans = "SWWAF_MAX_BANS"
banScopeV4Prefix = "SWWAF_BAN_SCOPE_V4_PREFIX"
stateDir = "SWWAF_STATE_DIR"
stateWriteDelay = "SWWAF_STATE_WRITE_DELAY"
stateCounterInterval = "SWWAF_STATE_COUNTER_INTERVAL"
metricsToken = "SWWAF_METRICS_TOKEN" //nolint:gosec // the setting's name
metricsTopN = "SWWAF_METRICS_TOP_N"
instanceName = "SWWAF_INSTANCE_NAME"
logRequestHeaders = "SWWAF_LOG_REQUEST_HEADERS"
)
// defaultLogRequestHeaders is the default of SWWAF_LOG_REQUEST_HEADERS.
const defaultLogRequestHeaders = "accept,accept-language,accept-encoding," +
"content-type,origin,range"
// token is a token of 32 characters, the shortest allowed.
const token = "0123456789abcdef0123456789abcdef"
// off switches a timeout, a size limit or a rate limit off.
const off = "off"
@@ -61,16 +91,30 @@ func TestDefaults(t *testing.T) {
cfg := fromEnvironment(t, environment{})
wantSettings(t, cfg, config.Config{
ListenAddr: ":8080",
ClientRequestTimeout: time.Minute,
ClientResponseTimeout: 30 * time.Minute,
UpstreamRequestTimeout: time.Minute,
UpstreamResponseTimeout: 30 * time.Minute,
RequestMaxBytes: 100 << 20,
ResponseMaxBytes: 5 << 30,
RateLimitPerMinute: 1000,
RateLimitPerHour: 10000,
RateLimitPerDay: 50000,
ListenAddr: ":8080",
Observe: false,
ClientRequestTimeout: time.Minute,
ClientRequestHeaderMaxBytes: 32 << 10,
ClientIdleTimeout: 2 * time.Minute,
ClientResponseTimeout: 30 * time.Minute,
UpstreamRequestTimeout: time.Minute,
UpstreamResponseTimeout: 30 * time.Minute,
RequestMaxBytes: 100 << 20,
ResponseMaxBytes: 5 << 30,
RateLimitPerMinute: 1000,
RateLimitPerHour: 10000,
RateLimitPerDay: 50000,
BanResponse: 403,
LimitBanDuration: time.Hour,
LimitBanRepeatWindow: 24 * time.Hour,
MaxBanDuration: 7 * 24 * time.Hour,
MaxBans: 5000,
BanScopeV4Prefix: 32,
StateDir: "/var/lib/smallwebwaf",
StateWriteDelay: 10 * time.Second,
StateCounterInterval: 15 * time.Minute,
MetricsToken: "",
MetricsTopN: 50,
})
if cfg.UpstreamURL.String() != "http://127.0.0.1:8081" {
@@ -79,6 +123,27 @@ func TestDefaults(t *testing.T) {
wantNetblocks(t, cfg.TrustedProxies,
"10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16")
wantNetblocks(t, cfg.AllowNets)
wantNetblocks(t, cfg.RateLimitExemptNets)
wantNetblocks(t, cfg.DenyNets)
wantCountries(t, deniedCountries, cfg.DeniedCountries)
wantCountries(t, allowedCountries, cfg.ExclusivelyAllowedCountries)
hostname, err := os.Hostname()
if err != nil || hostname == "" || cfg.InstanceName != hostname {
t.Errorf("%s is %q, want the host's name %q (%v)", instanceName,
cfg.InstanceName, hostname, err)
}
wantHeaders := strings.Split(defaultLogRequestHeaders, ",")
if !slices.Equal(cfg.LogRequestHeaders, wantHeaders) {
t.Errorf("%s gave %v, want %v", logRequestHeaders, cfg.LogRequestHeaders,
wantHeaders)
}
if len(cfg.RateLimitExemptPaths) != 0 {
t.Errorf("%s gave %v, want none", rateLimitExemptPaths, cfg.RateLimitExemptPaths)
}
}
func TestValuesAsSet(t *testing.T) {
@@ -87,29 +152,63 @@ func TestValuesAsSet(t *testing.T) {
cfg := fromEnvironment(t, environment{
listenAddr: "127.0.0.1:9000",
upstreamURL: "https://app.internal:8443/",
mode: "observe",
trustedProxies: " 192.0.2.1, 10.1.2.3/8 ,2001:db8::/32",
clientRequestTimeout: "90s",
clientHeaderMaxBytes: "8K",
clientIdleTimeout: "5m",
clientResponseTimeout: "7d",
upstreamRequestTimeout: "1h30m",
upstreamResponseTimeout: off,
requestMaxBytes: "512K",
responseMaxBytes: "1234",
allowNets: "192.0.2.7",
rateLimitExemptNets: "2001:db8::/48, 10.9.8.7",
denyNets: "198.51.100.0/24",
rateLimitPerMinute: "60",
rateLimitPerHour: "600",
rateLimitPerDay: "6000",
rateLimitExemptPaths: "/assets/, /favicon.ico",
deniedCountries: "cn, RU,kp,Xk",
allowedCountries: "de",
banResponse: "429",
limitBanDuration: "15m",
limitBanRepeatWindow: "2d",
maxBanDuration: "30d",
maxBans: "100",
banScopeV4Prefix: "24",
stateDir: "/srv/waf-state",
stateWriteDelay: "500ms",
stateCounterInterval: "1h",
metricsToken: token,
metricsTopN: "10",
})
wantSettings(t, cfg, config.Config{
ListenAddr: "127.0.0.1:9000",
ClientRequestTimeout: 90 * time.Second,
ClientResponseTimeout: 7 * 24 * time.Hour,
UpstreamRequestTimeout: 90 * time.Minute,
UpstreamResponseTimeout: 0,
RequestMaxBytes: 512 << 10,
ResponseMaxBytes: 1234,
RateLimitPerMinute: 60,
RateLimitPerHour: 600,
RateLimitPerDay: 6000,
ListenAddr: "127.0.0.1:9000",
Observe: true,
ClientRequestTimeout: 90 * time.Second,
ClientRequestHeaderMaxBytes: 8 << 10,
ClientIdleTimeout: 5 * time.Minute,
ClientResponseTimeout: 7 * 24 * time.Hour,
UpstreamRequestTimeout: 90 * time.Minute,
UpstreamResponseTimeout: 0,
RequestMaxBytes: 512 << 10,
ResponseMaxBytes: 1234,
RateLimitPerMinute: 60,
RateLimitPerHour: 600,
RateLimitPerDay: 6000,
BanResponse: 429,
LimitBanDuration: 15 * time.Minute,
LimitBanRepeatWindow: 48 * time.Hour,
MaxBanDuration: 30 * 24 * time.Hour,
MaxBans: 100,
BanScopeV4Prefix: 24,
StateDir: "/srv/waf-state",
StateWriteDelay: 500 * time.Millisecond,
StateCounterInterval: time.Hour,
MetricsToken: token,
MetricsTopN: 10,
})
if cfg.UpstreamURL.String() != "https://app.internal:8443/" {
@@ -117,6 +216,61 @@ func TestValuesAsSet(t *testing.T) {
}
wantNetblocks(t, cfg.TrustedProxies, "192.0.2.1/32", "10.0.0.0/8", "2001:db8::/32")
wantNetblocks(t, cfg.AllowNets, "192.0.2.7/32")
wantNetblocks(t, cfg.RateLimitExemptNets, "2001:db8::/48", "10.9.8.7/32")
wantNetblocks(t, cfg.DenyNets, "198.51.100.0/24")
wantCountries(t, deniedCountries, cfg.DeniedCountries, "CN", "RU", "KP", "XK")
wantCountries(t, allowedCountries, cfg.ExclusivelyAllowedCountries, "DE")
if !slices.Equal(cfg.RateLimitExemptPaths, []string{"/assets/", "/favicon.ico"}) {
t.Errorf("%s gave %v, want /assets/ and /favicon.ico",
rateLimitExemptPaths, cfg.RateLimitExemptPaths)
}
}
func TestPathPrefixNotStartingWithSlashStopsTheStart(t *testing.T) {
t.Parallel()
_, err := config.FromEnvironment(
environment{rateLimitExemptPaths: "/favicon.ico,assets/"}.lookupEnv)
want := rateLimitExemptPaths + `: "assets/" is not a path prefix ` +
`starting with /, such as /assets/`
if err == nil || err.Error() != want {
t.Errorf("error %v, want %s", err, want)
}
}
func TestInstanceNameAndLoggedHeadersAsSet(t *testing.T) {
t.Parallel()
cfg := fromEnvironment(t, environment{
instanceName: "fsn1app1/gitea",
logRequestHeaders: " Accept , X-Custom",
})
if cfg.InstanceName != "fsn1app1/gitea" ||
!slices.Equal(cfg.LogRequestHeaders, []string{"accept", "x-custom"}) {
t.Errorf("%s is %q and %s gives %v", instanceName, cfg.InstanceName,
logRequestHeaders, cfg.LogRequestHeaders)
}
}
func TestCodeOnBothCountryListsStopsTheStart(t *testing.T) {
t.Parallel()
_, err := config.FromEnvironment(environment{
deniedCountries: "cn,ru",
allowedCountries: "de,RU",
}.lookupEnv)
if err == nil {
t.Fatal("ru on both country lists was accepted")
}
if !strings.HasPrefix(err.Error(), allowedCountries+": ") ||
!strings.Contains(err.Error(), `"RU"`) {
t.Errorf("error %q does not name %s and RU", err, allowedCountries)
}
}
func TestSizesAndOff(t *testing.T) {
@@ -126,12 +280,42 @@ func TestSizesAndOff(t *testing.T) {
requestMaxBytes: "3G",
responseMaxBytes: off,
clientRequestTimeout: off,
clientIdleTimeout: off,
})
if cfg.RequestMaxBytes != 3<<30 || cfg.ResponseMaxBytes != 0 ||
cfg.ClientRequestTimeout != 0 {
t.Errorf("3G, off and off read as %d, %d and %s",
cfg.RequestMaxBytes, cfg.ResponseMaxBytes, cfg.ClientRequestTimeout)
cfg.ClientRequestTimeout != 0 || cfg.ClientIdleTimeout != 0 {
t.Errorf("3G, off, off and off read as %d, %d, %s and %s",
cfg.RequestMaxBytes, cfg.ResponseMaxBytes, cfg.ClientRequestTimeout,
cfg.ClientIdleTimeout)
}
}
func TestRequestHeaderMaxBytesJustOver4K(t *testing.T) {
t.Parallel()
cfg := fromEnvironment(t, environment{clientHeaderMaxBytes: "4097"})
if cfg.ClientRequestHeaderMaxBytes != 4097 {
t.Errorf("4097 read as %d", cfg.ClientRequestHeaderMaxBytes)
}
}
func TestRequestHeaderMaxBytesRefusalNeverOffersOff(t *testing.T) {
t.Parallel()
for _, value := range []string{"32KB", "0", "4K", off} {
t.Run(value, func(t *testing.T) {
t.Parallel()
_, err := config.FromEnvironment(
environment{clientHeaderMaxBytes: value}.lookupEnv)
want := clientHeaderMaxBytes + `: "` + value +
`" is not a size of more than 4K, such as 32K`
if err == nil || err.Error() != want {
t.Errorf("error %v, want %s", err, want)
}
})
}
}
@@ -151,6 +335,15 @@ func TestRateLimitsOff(t *testing.T) {
}
}
func TestBanResponseCloseIsZero(t *testing.T) {
t.Parallel()
cfg := fromEnvironment(t, environment{banResponse: "close"})
if cfg.BanResponse != 0 {
t.Errorf("close read as %d, want 0", cfg.BanResponse)
}
}
func TestTrustedProxiesSetButEmptyTrustNothing(t *testing.T) {
t.Parallel()
@@ -164,9 +357,7 @@ func TestInvalidValueStopsTheStart(t *testing.T) {
t.Parallel()
for _, tc := range []struct{ name, value string }{
{listenAddr, "8080"},
{listenAddr, ":http"},
{listenAddr, ":65536"},
{listenAddr, "8080"}, {listenAddr, ":http"}, {listenAddr, ":65536"},
{upstreamURL, "127.0.0.1:8081"},
{upstreamURL, "ftp://127.0.0.1:8081"},
{upstreamURL, "http://"},
@@ -176,12 +367,17 @@ func TestInvalidValueStopsTheStart(t *testing.T) {
{upstreamURL, "http://127.0.0.1:8081/app"},
{upstreamURL, "http://127.0.0.1:8081/?a=1"},
{upstreamURL, "http://user:secret@127.0.0.1:8081"},
{mode, "Observe"}, {mode, "block"}, {mode, ""},
{trustedProxies, "10.0.0.0/33"},
{trustedProxies, "traefik"},
{trustedProxies, "10.0.0.0/8,,192.168.0.0/16"},
{trustedProxies, "fe80::1%eth0"},
{clientRequestTimeout, "60"},
{clientRequestTimeout, ""},
{allowNets, "192.0.2.0/24,monitoring"},
{rateLimitExemptNets, "2001:db8::/129"},
{denyNets, "198.51.100.0/24,"},
{clientRequestTimeout, "60"}, {clientRequestTimeout, ""},
{clientIdleTimeout, "0s"},
{clientIdleTimeout, "2 minutes"},
{clientResponseTimeout, "1y"},
{upstreamRequestTimeout, "-1s"},
{upstreamResponseTimeout, "0s"},
@@ -196,8 +392,34 @@ func TestInvalidValueStopsTheStart(t *testing.T) {
{rateLimitPerMinute, "1K"},
{rateLimitPerHour, "0"},
{rateLimitPerHour, "1.5"},
{rateLimitPerDay, "-1"},
{rateLimitPerDay, "lots"},
{rateLimitPerDay, "-1"}, {rateLimitPerDay, "lots"},
{rateLimitExemptPaths, "/assets/,,/static/"},
{deniedCountries, "nk"},
{deniedCountries, "kp,,ir"},
{deniedCountries, "prk"},
{deniedCountries, "408"},
{deniedCountries, "k"},
{deniedCountries, "eu"},
{deniedCountries, "un"},
{deniedCountries, "su"},
{allowedCountries, "ac"},
{allowedCountries, "uk"},
{allowedCountries, "zz"},
{allowedCountries, "de,germany"},
{banResponse, "404"}, {banResponse, "drop"}, {banResponse, ""},
{limitBanDuration, off}, {limitBanDuration, "0s"}, {limitBanDuration, "1"},
{limitBanRepeatWindow, off}, {limitBanRepeatWindow, "-1h"},
{maxBanDuration, off}, {maxBanDuration, "1w"},
{maxBans, off}, {maxBans, "0"}, {maxBans, "5K"},
{banScopeV4Prefix, "33"}, {banScopeV4Prefix, "-1"}, {banScopeV4Prefix, "/24"},
{stateDir, ""}, {stateDir, "state"}, {stateDir, "./var/lib/smallwebwaf"},
{stateWriteDelay, off}, {stateWriteDelay, "0s"},
{stateCounterInterval, off}, {stateCounterInterval, "15"},
{metricsTopN, off}, {metricsTopN, "0"}, {metricsTopN, "-1"},
{logRequestHeaders, "accept,,origin"}, {logRequestHeaders, "accept;origin"},
{logRequestHeaders, "accept language"}, {logRequestHeaders, "x-foo:"},
{logRequestHeaders, "host"}, {logRequestHeaders, "accept,Host"},
{logRequestHeaders, "transfer-encoding"}, {logRequestHeaders, "TRANSFER-ENCODING"},
} {
t.Run(tc.name+"="+tc.value, func(t *testing.T) {
t.Parallel()
@@ -214,6 +436,60 @@ func TestInvalidValueStopsTheStart(t *testing.T) {
}
}
func TestHostOrTransferEncodingStopsTheStart(t *testing.T) {
t.Parallel()
// Only Host's message points to the field host.
for value, want := range map[string]string{
"Host": `"Host" is taken out of every request by Go's HTTP server, ` +
"so it can never be logged; the request's host is the field host",
"transfer-encoding": `"transfer-encoding" is taken out of every ` +
"request by Go's HTTP server, so it can never be logged",
} {
t.Run(value, func(t *testing.T) {
t.Parallel()
_, err := config.FromEnvironment(environment{logRequestHeaders: value}.lookupEnv)
if err == nil || err.Error() != logRequestHeaders+": "+want {
t.Errorf("error %v, want %s: %s", err, logRequestHeaders, want)
}
})
}
}
func TestShortTokenStopsTheStartWithoutShowingIt(t *testing.T) {
t.Parallel()
// Characters are counted, not bytes: each é takes two.
for _, value := range []string{"", token[1:], strings.Repeat("é", 31)} {
t.Run(value, func(t *testing.T) {
t.Parallel()
_, err := config.FromEnvironment(environment{metricsToken: value}.lookupEnv)
want := metricsToken + ": is shorter than 32 characters"
if err == nil || err.Error() != want {
t.Errorf("error %v, want %s", err, want)
}
})
}
}
func TestTokenIsLoggedMasked(t *testing.T) {
t.Parallel()
cfg := fromEnvironment(t, environment{metricsToken: token})
var out bytes.Buffer
slog.New(slog.NewJSONHandler(&out, nil)).Info("starting", "settings", cfg)
if strings.Contains(out.String(), token) ||
!strings.Contains(out.String(), `"`+metricsToken+`":"********"`) {
t.Errorf("the token is not logged masked: %s", out.String())
}
}
func TestLogsEachSettingWithItsValue(t *testing.T) {
t.Parallel()
@@ -232,19 +508,43 @@ func TestLogsEachSettingWithItsValue(t *testing.T) {
t.Fatalf("decode %s: %v", out.Bytes(), err)
}
hostname, _ := os.Hostname()
want := map[string]string{
listenAddr: ":8080",
upstreamURL: "http://127.0.0.1:8081",
mode: "enforce",
trustedProxies: "10.0.0.0/8,172.16.0.0/12,192.168.0.0/16",
clientRequestTimeout: "45s",
clientHeaderMaxBytes: "32K",
clientIdleTimeout: "120s",
clientResponseTimeout: "30m",
upstreamRequestTimeout: "60s",
upstreamResponseTimeout: "30m",
requestMaxBytes: "100M",
responseMaxBytes: "5G",
allowNets: "",
rateLimitExemptNets: "",
denyNets: "",
rateLimitPerMinute: "1000",
rateLimitPerHour: "10000",
rateLimitPerDay: "50000",
rateLimitExemptPaths: "",
deniedCountries: "",
allowedCountries: "",
banResponse: "403",
limitBanDuration: "1h",
limitBanRepeatWindow: "24h",
maxBanDuration: "7d",
maxBans: "5000",
banScopeV4Prefix: "32",
stateDir: "/var/lib/smallwebwaf",
stateWriteDelay: "10s",
stateCounterInterval: "15m",
metricsToken: "",
metricsTopN: "50",
instanceName: hostname,
logRequestHeaders: defaultLogRequestHeaders,
}
if !maps.Equal(line.Settings, want) {
t.Errorf("logged settings\n%v\nwant\n%v", line.Settings, want)
@@ -256,7 +556,10 @@ func wantSettings(t *testing.T, got *config.Config, want config.Config) {
t.Helper()
if got.ListenAddr != want.ListenAddr ||
got.Observe != want.Observe ||
got.ClientRequestTimeout != want.ClientRequestTimeout ||
got.ClientRequestHeaderMaxBytes != want.ClientRequestHeaderMaxBytes ||
got.ClientIdleTimeout != want.ClientIdleTimeout ||
got.ClientResponseTimeout != want.ClientResponseTimeout ||
got.UpstreamRequestTimeout != want.UpstreamRequestTimeout ||
got.UpstreamResponseTimeout != want.UpstreamResponseTimeout ||
@@ -267,6 +570,34 @@ func wantSettings(t *testing.T, got *config.Config, want config.Config) {
got.RateLimitPerDay != want.RateLimitPerDay {
t.Errorf("settings\n%+v\nwant\n%+v", got, want)
}
wantBanSettings(t, got, want)
}
// wantBanSettings checks the settings for bans, the state files and the
// metrics.
func wantBanSettings(t *testing.T, got *config.Config, want config.Config) {
t.Helper()
if got.BanResponse != want.BanResponse ||
got.LimitBanDuration != want.LimitBanDuration ||
got.LimitBanRepeatWindow != want.LimitBanRepeatWindow ||
got.MaxBanDuration != want.MaxBanDuration ||
got.MaxBans != want.MaxBans ||
got.BanScopeV4Prefix != want.BanScopeV4Prefix {
t.Errorf("ban settings\n%+v\nwant\n%+v", got, want)
}
if got.StateDir != want.StateDir ||
got.StateWriteDelay != want.StateWriteDelay ||
got.StateCounterInterval != want.StateCounterInterval {
t.Errorf("state settings\n%+v\nwant\n%+v", got, want)
}
if got.MetricsToken != want.MetricsToken || got.MetricsTopN != want.MetricsTopN {
t.Errorf("metrics token %q and top %d, want %q and %d",
got.MetricsToken, got.MetricsTopN, want.MetricsToken, want.MetricsTopN)
}
}
// wantNetblocks checks a list of netblocks.
@@ -282,3 +613,12 @@ func wantNetblocks(t *testing.T, got []netip.Prefix, want ...string) {
t.Errorf("netblocks %v, want %v", gotText, want)
}
}
// wantCountries checks the list of countries the setting name gave.
func wantCountries(t *testing.T, name string, got []string, want ...string) {
t.Helper()
if !slices.Equal(got, want) {
t.Errorf("%s gave %v, want %v", name, got, want)
}
}
internal/lookup/export_test.go
+9
View File
@@ -0,0 +1,9 @@
package lookup
import "net/http"
// SetTransport has g's requests to GeoJS go through transport instead of
// the network.
func (g *GeoJS) SetTransport(transport http.RoundTripper) {
g.httpClient.Transport = transport
}
internal/lookup/lookup.go
+456
View File
@@ -0,0 +1,456 @@
// Package lookup looks up each client's country through the GeoJS web
// service, and keeps the answers in memory, for at most 100,000 clients
// and for 7 days each. The answers are written to lookups.json and read
// from it by the state package.
package lookup
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"log/slog"
"net/http"
"net/netip"
"slices"
"strings"
"sync"
"time"
"github.com/hashicorp/golang-lru/v2/simplelru"
"sneak.berlin/go/smallwebwaf/internal/metrics"
)
// URL is GeoJS's country endpoint. Asked about several addresses at once,
// comma separated in its ip parameter, it answers with a list.
const URL = "https://get.geojs.io/v1/ip/country.json"
const (
// keepFor is how long an answer is used instead of asking GeoJS again.
keepFor = 7 * 24 * time.Hour
// maxAnswers is how many answers are kept. Past it, the one used
// longest ago is dropped.
maxAnswers = 100000
// maxWaiting is how many clients may wait to be asked about. Past it,
// a new client counts as not found and is not asked about until there
// is room, so that a swarm of new addresses while GeoJS is down cannot
// fill the memory.
maxWaiting = 10000
// maxPerRequest is how many addresses one request to GeoJS asks about.
maxPerRequest = 200
// timeout is how long a new client waits for its answer, and how long
// a request to GeoJS may take before it is abandoned.
timeout = time.Second
// After a failure GeoJS is not asked again for a second, and for
// retryDelayFactor times as long after each further failure in a row,
// up to five minutes.
firstRetryDelay = time.Second
retryDelayFactor = 2
maxRetryDelay = 5 * time.Minute
// maxResponseBytes is the most of GeoJS's answer that is read.
maxResponseBytes = 1 << 20
)
var (
errStatus = errors.New("GeoJS answered")
errLeftOut = errors.New("GeoJS's answer left out")
)
// Params are what New needs.
type Params struct {
// URL is where GeoJS is asked, normally URL.
URL string
// Now tells the time, normally time.Now.
Now func() time.Time
// ProcessLog receives GeoJS's failures.
ProcessLog *slog.Logger
// Metrics count the requests to GeoJS, those that failed, and the
// clients that go without an answer.
Metrics *metrics.Metrics
}
// GeoJS looks up clients' countries through GeoJS. At most one request
// to GeoJS is under way at a time, and it asks about every client waiting,
// up to maxPerRequest. It is safe for concurrent use.
type GeoJS struct {
url string
now func() time.Time
processLog *slog.Logger
metrics *metrics.Metrics
// httpClient follows no redirect, so that visitors' addresses go to
// GeoJS alone: a redirect is a failure.
httpClient *http.Client
mu sync.Mutex
answers *simplelru.LRU[netip.Prefix, *Answer]
// waiting are the clients without an answer: those to ask GeoJS about,
// and those it is being asked about.
waiting map[netip.Prefix]*wait
// asking is true while a request to GeoJS is under way.
asking bool
// retryDelay is how long GeoJS is left alone after its last failure,
// zero after an answer; retryAt is when it may be asked again.
retryDelay time.Duration
retryAt time.Time
}
// Answer is what GeoJS said about a client, as lookups.json holds it: its
// country, "" when GeoJS cannot place it, when GeoJS said so, and when
// the answer was last used.
type Answer struct {
Client netip.Prefix `json:"client"`
Country string `json:"country"`
Answered time.Time `json:"answered"`
Used time.Time `json:"used"`
}
// wait is a client waiting for its answer.
type wait struct {
// asked is closed when the client gets its answer, and closed and
// replaced each time GeoJS fails before then.
asked chan struct{}
// late is true once the client has gone without an answer, for a
// whole timeout or because GeoJS failed: its requests no longer wait.
late bool
}
// New returns a GeoJS with no answer kept yet.
func New(params Params) *GeoJS {
answers, err := simplelru.NewLRU[netip.Prefix, *Answer](maxAnswers, nil)
if err != nil {
panic(err) // NewLRU fails only for a size below one
}
return &GeoJS{
url: params.URL,
now: params.Now,
processLog: params.ProcessLog,
metrics: params.Metrics,
httpClient: &http.Client{
CheckRedirect: func(*http.Request, []*http.Request) error {
return http.ErrUseLastResponse
},
},
answers: answers,
waiting: map[netip.Prefix]*wait{},
}
}
// Country returns the country GeoJS places client in, as a two-letter
// code in capitals, or "" when the country cannot be found: GeoJS cannot
// place the client, or has not answered in time. An answer is kept for 7
// days. Without one, a client waits up to timeout for it, unless it has
// gone without one before; until GeoJS answers, the client is asked about
// again in the background. ctx is the context of the client's request,
// and ends the wait when it ends.
//
// GeoJS is asked about the client's first address, which is the client's
// own address for IPv4, and an address in the same place for an IPv6 /64.
func (g *GeoJS) Country(ctx context.Context, client netip.Prefix) string {
country, asked := g.answerOrWait(ctx, client)
if asked == nil {
return country
}
timer := time.NewTimer(timeout)
defer timer.Stop()
select {
case <-asked:
case <-timer.C:
case <-ctx.Done():
}
g.mu.Lock()
defer g.mu.Unlock()
country, found := g.kept(client)
if !found {
g.metrics.GeoJSUnanswered.Inc()
}
w, waiting := g.waiting[client]
if !found && waiting {
w.late = true
}
return country
}
// Snapshot returns every answer kept, sorted by client, as lookups.json
// lists them.
func (g *GeoJS) Snapshot() []Answer {
g.mu.Lock()
answers := make([]Answer, 0, g.answers.Len())
for _, kept := range g.answers.Values() {
answers = append(answers, *kept)
}
g.mu.Unlock()
slices.SortFunc(answers, func(a, b Answer) int {
return a.Client.Compare(b.Client)
})
return answers
}
// Load keeps answers read from lookups.json, in place of the answers it
// keeps, in the order they were last used, so that the one used longest
// ago is dropped first. Answers GeoJS gave keepFor ago or more are
// dropped.
func (g *GeoJS) Load(answers []Answer) {
answers = slices.Clone(answers)
slices.SortStableFunc(answers, func(a, b Answer) int {
return a.Used.Compare(b.Used)
})
g.mu.Lock()
defer g.mu.Unlock()
g.answers.Purge()
now := g.now()
for _, answer := range answers {
if now.Sub(answer.Answered) < keepFor {
g.answers.Add(answer.Client, &answer)
}
}
}
// answerOrWait returns client's kept answer if it has one. Otherwise it
// puts the client among those waiting if there is room, has GeoJS asked
// about them if it can be, and returns what to wait on for the answer, or
// nil when there is nothing to wait for.
func (g *GeoJS) answerOrWait(
ctx context.Context, client netip.Prefix,
) (string, <-chan struct{}) {
g.mu.Lock()
defer g.mu.Unlock()
country, found := g.kept(client)
if found {
return country, nil
}
w, waiting := g.waiting[client]
if !waiting && len(g.waiting) < maxWaiting {
w = &wait{asked: make(chan struct{})}
g.waiting[client] = w
}
g.ask(ctx)
if w == nil {
g.metrics.GeoJSUnanswered.Inc()
return "", nil // too many clients wait already
}
if !g.asking {
// GeoJS is left alone after a failure, so no answer can come.
w.late = true
}
if w.late {
g.metrics.GeoJSUnanswered.Inc()
return "", nil
}
return "", w.asked
}
// kept returns client's answer, if GeoJS gave it less than keepFor ago,
// and notes that it was used.
func (g *GeoJS) kept(client netip.Prefix) (string, bool) {
now := g.now()
kept, found := g.answers.Get(client)
if !found || now.Sub(kept.Answered) >= keepFor {
return "", false
}
kept.Used = now
return kept.Country, true
}
// ask starts asking GeoJS about the waiting clients, unless a request to
// it is under way or it is left alone after a failure. The requests to
// GeoJS are for every client waiting, so they go on when the client's
// request whose ctx is given ends.
func (g *GeoJS) ask(ctx context.Context) {
if g.asking || g.now().Before(g.retryAt) {
return
}
g.asking = true
go g.askAboutWaiting(context.WithoutCancel(ctx))
}
// askAboutWaiting asks GeoJS about the waiting clients, one request at a
// time, until none is left or GeoJS fails.
func (g *GeoJS) askAboutWaiting(ctx context.Context) {
for {
clients := g.nextClients()
if len(clients) == 0 {
return
}
countries, err := g.request(ctx, clients)
if !g.keep(clients, countries, err) {
return
}
}
}
// nextClients returns up to maxPerRequest of the waiting clients. When
// none is waiting, it returns none and notes that no request to GeoJS is
// under way.
func (g *GeoJS) nextClients() []netip.Prefix {
g.mu.Lock()
defer g.mu.Unlock()
if len(g.waiting) == 0 {
g.asking = false
return nil
}
clients := make([]netip.Prefix, 0, min(len(g.waiting), maxPerRequest))
for client := range g.waiting {
if len(clients) == maxPerRequest {
break
}
clients = append(clients, client)
}
return clients
}
// keep notes how a request to GeoJS about clients ended, and reports
// whether GeoJS answered about all of them. Each client whose address
// GeoJS's answer names gets its answer, with no country when GeoJS gave
// none. An answer that leaves an address out is a failure. After a
// failure GeoJS is left alone for a while, and every client still waiting
// stops waiting and is asked about once GeoJS is asked again.
func (g *GeoJS) keep(
clients []netip.Prefix, countries map[netip.Addr]string, err error,
) bool {
g.mu.Lock()
defer g.mu.Unlock()
now := g.now()
leftOut := 0
for _, client := range clients {
country, named := countries[client.Addr()]
if !named {
leftOut++
continue
}
g.answers.Add(client, &Answer{
Client: client, Country: country, Answered: now, Used: now,
})
close(g.waiting[client].asked)
delete(g.waiting, client)
}
if err == nil && leftOut > 0 {
err = fmt.Errorf("%w %d of %d addresses", errLeftOut, leftOut, len(clients))
}
if err != nil {
g.metrics.GeoJSFailures.Inc()
g.retryDelay = min(max(retryDelayFactor*g.retryDelay, firstRetryDelay),
maxRetryDelay)
g.retryAt = now.Add(g.retryDelay)
g.asking = false
for _, w := range g.waiting {
close(w.asked)
w.asked = make(chan struct{})
w.late = true
}
g.processLog.Warn("asking GeoJS failed",
"error", err.Error(), "asking_again_in", g.retryDelay.String())
return false
}
g.retryDelay = 0
return true
}
// request asks GeoJS about clients in one request, and returns the
// country it gave, in capitals, for each address its answer names.
func (g *GeoJS) request(
ctx context.Context, clients []netip.Prefix,
) (map[netip.Addr]string, error) {
addrs := make([]string, 0, len(clients))
for _, client := range clients {
addrs = append(addrs, client.Addr().String())
}
ctx, cancel := context.WithTimeout(ctx, timeout)
defer cancel()
req, err := http.NewRequestWithContext(ctx, http.MethodGet, g.url, http.NoBody)
if err != nil {
return nil, fmt.Errorf("make the request to GeoJS: %w", err)
}
req.URL.RawQuery = "ip=" + strings.Join(addrs, ",")
g.metrics.GeoJSRequests.Inc()
res, err := g.httpClient.Do(req)
if err != nil {
// Do's error names the URL, and so the visitors' addresses, which
// are not to be logged: only what went wrong is kept.
return nil, fmt.Errorf("ask GeoJS: %w", errors.Unwrap(err))
}
defer func() {
_ = res.Body.Close()
}()
if res.StatusCode != http.StatusOK {
return nil, fmt.Errorf("%w %s", errStatus, res.Status)
}
var answers []struct {
IP string `json:"ip"`
Country string `json:"country"`
}
err = json.NewDecoder(io.LimitReader(res.Body, maxResponseBytes)).Decode(&answers)
if err != nil {
return nil, fmt.Errorf("read GeoJS's answer: %w", err)
}
countries := make(map[netip.Addr]string, len(answers))
for _, item := range answers {
addr, err := netip.ParseAddr(item.IP)
if err == nil {
countries[addr] = strings.ToUpper(item.Country)
}
}
return countries, nil
}
internal/lookup/lookup_test.go
+631
View File
@@ -0,0 +1,631 @@
package lookup_test
import (
"encoding/json"
"log/slog"
"net/http"
"net/http/httptest"
"net/netip"
"slices"
"strings"
"sync"
"testing"
"testing/synctest"
"time"
"github.com/prometheus/client_golang/prometheus/testutil"
"sneak.berlin/go/smallwebwaf/internal/lookup"
"sneak.berlin/go/smallwebwaf/internal/metrics"
)
const (
// germany is where the stand-in for GeoJS places every address but
// unplaced.
germany = "DE"
// unplaced is the address it cannot place.
unplaced = "192.0.2.1"
// leftOut is the address it leaves out of its answer when
// answeringWithoutLeftOut.
leftOut = "203.0.113.7"
// timeout is how long a new client waits for its answer.
timeout = time.Second
// week is how long an answer is kept.
week = 7 * 24 * time.Hour
)
// The tests that have GeoJS asked run in a synctest bubble, where the time
// package runs on a clock of the test's own: a wait lasts exactly as long
// as it should, however slowly the test process runs, and synctest.Wait
// returns once g has done all it can before time passes. The stand-in for
// GeoJS answers without the network, since a request waiting on the
// network would keep that clock from moving on.
func TestKeptAnswerIsUsedFor7DaysThenAskedAgain(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
placed := netip.MustParsePrefix("203.0.113.9/32")
notPlaced := netip.MustParsePrefix(unplaced + "/32")
wantCountry(t, g, placed, germany)
wantCountry(t, g, notPlaced, "")
wantRequests(t, geojs, 2)
// An answer without a country is kept too.
clock.advance(week - time.Second)
wantCountry(t, g, placed, germany)
wantCountry(t, g, notPlaced, "")
wantRequests(t, geojs, 2)
clock.advance(time.Second)
wantCountry(t, g, placed, germany)
wantRequests(t, geojs, 3)
wantAsked(t, geojs, 2, "203.0.113.9")
})
}
func TestNewClientWaitsAtMostOneSecondThenCountsAsNotFound(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
client := netip.MustParsePrefix("203.0.113.9/32")
// The client comes while GeoJS is asked about an earlier client, which
// it answers most of a second later. It is then asked about the client
// and does not answer: that request is abandoned a second after it
// began, well after the client's wait is over.
geojs.set(answeringSlowly)
var earlier sync.WaitGroup
earlier.Go(func() { g.Country(t.Context(), netip.MustParsePrefix("203.0.113.1/32")) })
defer earlier.Wait()
waitForRequests(t, geojs, 1)
geojs.set(hanging)
began := time.Now()
wantCountry(t, g, client, "")
took := time.Since(began)
if took != timeout {
t.Errorf("waited %s for the answer, want %s", took, timeout)
}
// Its next request does not wait.
began = time.Now()
wantCountry(t, g, client, "")
took = time.Since(began)
if took != 0 {
t.Errorf("waited %s again, want no wait", took)
}
// Once GeoJS answers, the client is asked about again in the
// background, and has its country.
geojs.set(answering)
waitForCountry(t, g, clock, client, germany)
})
}
func TestAddressLeftOutOfAnAnswerIsAskedAboutAgain(t *testing.T) {
t.Parallel()
for _, tc := range []struct {
name string
answers int
// named is whether the answer names the other client asked about.
named bool
}{
{"null", answeringNull, false},
{"empty list", answeringEmptyList, false},
{"list without " + leftOut, answeringWithoutLeftOut, true},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
other := netip.MustParsePrefix("203.0.113.1/32")
client := netip.MustParsePrefix(leftOut + "/32")
// GeoJS fails, and is left alone for a second while the client
// comes too, so that the next request asks about both.
geojs.set(failing)
wantCountry(t, g, other, "")
wantCountry(t, g, client, "")
geojs.set(tc.answers)
clock.advance(time.Second)
wantCountry(t, g, other, "")
waitForRequests(t, geojs, 2)
// The answer counts as a failure, and the client is asked about
// again, with the other client only if the answer left it out too.
geojs.set(answering)
waitForCountry(t, g, clock, client, germany)
wantCountry(t, g, other, germany)
wantRequests(t, geojs, 3)
if tc.named {
wantAsked(t, geojs, 2, leftOut)
} else {
wantAsked(t, geojs, 2, leftOut, "203.0.113.1")
}
})
})
}
}
func TestRedirectCountsAsFailure(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, _, g := start()
geojs.set(redirecting)
wantCountry(t, g, netip.MustParsePrefix("203.0.113.9/32"), "")
wantRequests(t, geojs, 1)
})
}
func TestCountryIsKeptInCapitals(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, _, g := start()
geojs.set(answeringInLowerCase)
wantCountry(t, g, netip.MustParsePrefix("203.0.113.9/32"), germany)
})
}
func TestFailureIsLoggedWithoutTheAddressesAskedAbout(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
var log strings.Builder
// GeoJS does not answer, so the request to it is abandoned, and fails.
geojs := &standIn{answers: hanging}
g := lookup.New(lookup.Params{
URL: lookup.URL,
Now: time.Now,
ProcessLog: slog.New(slog.NewTextHandler(&log, nil)),
Metrics: metrics.New(1),
})
g.SetTransport(geojs)
wantCountry(t, g, netip.MustParsePrefix("203.0.113.9/32"), "")
synctest.Wait()
logged := log.String()
if !strings.Contains(logged, "asking GeoJS failed") ||
strings.Contains(logged, "203.0.113.9") {
t.Errorf("logged %q, want the failure without the address asked about", logged)
}
})
}
func TestWaitingClientsAreAskedAboutInOneRequest(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
// GeoJS fails, and is then left alone for a second, while three more
// clients come. An IPv6 client is a /64, and GeoJS is asked about its
// first address.
geojs.set(failing)
wantCountry(t, g, netip.MustParsePrefix("203.0.113.1/32"), "")
wantCountry(t, g, netip.MustParsePrefix("203.0.113.2/32"), "")
wantCountry(t, g, netip.MustParsePrefix("2001:db8:1:2::/64"), "")
wantRequests(t, geojs, 1)
geojs.set(answering)
clock.advance(time.Second)
wantCountry(t, g, netip.MustParsePrefix("203.0.113.3/32"), germany)
wantRequests(t, geojs, 2)
wantAsked(t, geojs, 1, "203.0.113.1", "203.0.113.2", "2001:db8:1:2::", "203.0.113.3")
})
}
func TestKeptAnswersUnaffectedWhileGeoJSFailsAndAskedAgainWithBackoff(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
clients := newClients()
kept := clients()
wantCountry(t, g, kept, germany)
geojs.set(failing)
wantCountry(t, g, kept, germany)
wantRequests(t, geojs, 1)
// Each failure leaves GeoJS alone twice as long as the one before, up
// to five minutes. New clients meanwhile count as not found, and the
// client with a kept answer still gets its country, without GeoJS being
// asked.
requests := 1
for _, delay := range []time.Duration{
time.Second, 2 * time.Second, 4 * time.Second, 8 * time.Second,
16 * time.Second, 32 * time.Second, 64 * time.Second, 128 * time.Second,
256 * time.Second, 5 * time.Minute, 5 * time.Minute,
} {
wantCountry(t, g, clients(), "")
requests++
wantRequests(t, geojs, requests)
clock.advance(delay - time.Millisecond)
wantCountry(t, g, clients(), "")
wantCountry(t, g, kept, germany)
wantRequests(t, geojs, requests)
clock.advance(time.Millisecond)
}
// Once GeoJS answers again, it is asked about every client waiting.
geojs.set(answering)
wantCountry(t, g, clients(), germany)
wantRequests(t, geojs, requests+1)
asked := waitForRequests(t, geojs, requests+1)
if len(asked[requests]) != 23 {
t.Errorf("GeoJS was asked about %d clients, want 23", len(asked[requests]))
}
})
}
func TestAtMost200AddressesInOneRequest(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
clients := newClients()
first := clients()
// 201 clients wait while GeoJS is left alone after a failure.
geojs.set(failing)
wantCountry(t, g, first, "")
for range 200 {
wantCountry(t, g, clients(), "")
}
// The first one's next request has GeoJS asked again.
geojs.set(answering)
clock.advance(time.Second)
wantCountry(t, g, first, "")
asked := waitForRequests(t, geojs, 3)
if len(asked[1]) != 200 || len(asked[2]) != 1 {
t.Errorf("GeoJS was asked about %d and then %d clients, want 200 and 1",
len(asked[1]), len(asked[2]))
}
})
}
func TestAtMost10000ClientsWait(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
geojs, clock, g := start()
clients := newClients()
first := clients()
// 10,000 clients wait while GeoJS is left alone after a failure, and
// one more cannot join them.
geojs.set(failing)
wantCountry(t, g, first, "")
for range 9999 {
wantCountry(t, g, clients(), "")
}
extra := clients()
wantCountry(t, g, extra, "")
// The first one's next request has GeoJS asked about the 10,000, 200
// at a time, and not about the one more.
geojs.set(answering)
clock.advance(time.Second)
wantCountry(t, g, first, "")
asked := waitForRequests(t, geojs, 51)
for i, request := range asked {
if slices.Contains(request, extra.Addr().String()) {
t.Errorf("request %d asked about %s", i, extra.Addr())
}
}
// With room among those waiting, it is asked about.
wantCountry(t, g, extra, germany)
})
}
func TestClientsWithoutAnAnswerAreCounted(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
m := metrics.New(1)
g := lookup.New(lookup.Params{
URL: lookup.URL,
Now: time.Now,
ProcessLog: slog.New(slog.DiscardHandler),
Metrics: m,
})
g.SetTransport(&standIn{answers: failing})
clients := newClients()
// GeoJS fails, so the first client goes without an answer, and GeoJS
// is left alone for a second, which does not pass in this test.
wantCountry(t, g, clients(), "")
wantUnanswered(t, m, 1)
// Meanwhile each new client goes without one at once, while there is
// room for it among the 10,000 that may wait.
for range 9999 {
wantCountry(t, g, clients(), "")
}
wantUnanswered(t, m, 10000)
// One more, for which there is no room, goes without one too.
wantCountry(t, g, clients(), "")
wantUnanswered(t, m, 10001)
})
}
// How the stand-in for GeoJS answers.
const (
answering = iota
answeringSlowly // most of a second later
answeringInLowerCase // with each country in lower case
answeringWithoutLeftOut // with a list that leaves leftOut out
answeringEmptyList // with []
answeringNull // with null
failing // with 503
hanging // not at all, until the request is abandoned
redirecting // with a redirect to itself
)
// standIn is a stand-in for GeoJS. It notes the addresses each request
// asks about.
type standIn struct {
mu sync.Mutex
answers int
requests [][]string
}
// RoundTrip has the stand-in answer req, in place of the network. A request
// abandoned before the stand-in answers fails, as over the network.
func (s *standIn) RoundTrip(req *http.Request) (*http.Response, error) {
answer := httptest.NewRecorder()
s.ServeHTTP(answer, req)
err := req.Context().Err()
if err != nil {
return nil, err
}
return answer.Result(), nil
}
// ServeHTTP answers a request about the addresses in its ip parameter.
func (s *standIn) ServeHTTP(w http.ResponseWriter, r *http.Request) {
addrs := strings.Split(r.URL.Query().Get("ip"), ",")
s.mu.Lock()
s.requests = append(s.requests, addrs)
answers := s.answers
s.mu.Unlock()
switch answers {
case failing:
w.WriteHeader(http.StatusServiceUnavailable)
return
case hanging:
<-r.Context().Done()
return
case redirecting:
http.Redirect(w, r, "/", http.StatusFound)
return
case answeringSlowly:
select {
case <-time.After(timeout * 4 / 5):
case <-r.Context().Done():
return
}
}
list := make([]map[string]string, 0, len(addrs))
for _, addr := range addrs {
country := germany
switch {
case addr == unplaced:
country = ""
case addr == leftOut && answers == answeringWithoutLeftOut:
continue
case answers == answeringInLowerCase:
country = strings.ToLower(germany)
}
list = append(list, map[string]string{"ip": addr, "country": country})
}
var answer any = list
switch answers {
case answeringEmptyList:
answer = []string{}
case answeringNull:
answer = nil
}
err := json.NewEncoder(w).Encode(answer)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
// set sets how the stand-in answers.
func (s *standIn) set(answers int) {
s.mu.Lock()
defer s.mu.Unlock()
s.answers = answers
}
// asked returns the addresses each request has asked about so far.
func (s *standIn) asked() [][]string {
s.mu.Lock()
defer s.mu.Unlock()
return slices.Clone(s.requests)
}
// testClock is a clock the test sets. GeoJS tells the time by it, while
// waits run on the bubble's clock.
type testClock struct {
mu sync.Mutex
now time.Time
}
// Now tells the time.
func (c *testClock) Now() time.Time {
c.mu.Lock()
defer c.mu.Unlock()
return c.now
}
// advance moves the clock on by d.
func (c *testClock) advance(d time.Duration) {
c.mu.Lock()
defer c.mu.Unlock()
c.now = c.now.Add(d)
}
// start returns a stand-in for GeoJS that answers, a clock, and a GeoJS
// asking the stand-in by that clock.
func start() (*standIn, *testClock, *lookup.GeoJS) {
geojs := &standIn{}
clock := &testClock{now: time.Date(2026, 10, 4, 0, 0, 0, 0, time.UTC)}
g := lookup.New(lookup.Params{
URL: lookup.URL,
Now: clock.Now,
ProcessLog: slog.New(slog.DiscardHandler),
Metrics: metrics.New(1),
})
g.SetTransport(geojs)
return geojs, clock, g
}
// newClients returns what returns a new IPv4 client each time it is
// called.
func newClients() func() netip.Prefix {
addr := netip.MustParseAddr("10.0.0.0")
return func() netip.Prefix {
addr = addr.Next()
return netip.PrefixFrom(addr, addr.BitLen())
}
}
// wantCountry checks the country g gives client.
func wantCountry(t *testing.T, g *lookup.GeoJS, client netip.Prefix, want string) {
t.Helper()
got := g.Country(t.Context(), client)
if got != want {
t.Errorf("%s is in %q, want %q", client, got, want)
}
}
// wantRequests checks how many requests GeoJS has had.
func wantRequests(t *testing.T, geojs *standIn, want int) {
t.Helper()
got := len(geojs.asked())
if got != want {
t.Errorf("GeoJS had %d requests, want %d", got, want)
}
}
// wantAsked checks the addresses request i asked about, in any order.
func wantAsked(t *testing.T, geojs *standIn, i int, want ...string) {
t.Helper()
asked := geojs.asked()
if len(asked) <= i {
t.Fatalf("GeoJS had %d requests, want more than %d", len(asked), i)
}
got := slices.Sorted(slices.Values(asked[i]))
slices.Sort(want)
if !slices.Equal(got, want) {
t.Errorf("request %d asked about %v, want %v", i, got, want)
}
}
// wantUnanswered checks how many requests m counts as having gone without
// an answer from GeoJS.
func wantUnanswered(t *testing.T, m *metrics.Metrics, want float64) {
t.Helper()
got := testutil.ToFloat64(m.GeoJSUnanswered)
if got != want {
t.Errorf("%v requests went without an answer, want %v", got, want)
}
}
// waitForRequests waits until g has done all it can before time passes,
// checks that GeoJS has had count requests, and returns the addresses each
// asked about.
func waitForRequests(t *testing.T, geojs *standIn, count int) [][]string {
t.Helper()
synctest.Wait()
asked := geojs.asked()
if len(asked) != count {
t.Fatalf("GeoJS had %d requests, want %d", len(asked), count)
}
return asked
}
// waitForCountry lets a request to GeoJS under way be abandoned, and moves
// the clock on a minute, so that GeoJS may be asked again after a failure.
// It then checks that client's next request does not wait but has it asked
// about again in the background, after which g gives it the country want.
func waitForCountry(
t *testing.T, g *lookup.GeoJS, clock *testClock, client netip.Prefix, want string,
) {
t.Helper()
time.Sleep(timeout)
clock.advance(time.Minute)
wantCountry(t, g, client, "")
synctest.Wait()
wantCountry(t, g, client, want)
}
internal/lookup/snapshot_test.go
+99
View File
@@ -0,0 +1,99 @@
package lookup_test
import (
"net/netip"
"slices"
"testing"
"testing/synctest"
"time"
"sneak.berlin/go/smallwebwaf/internal/lookup"
)
func TestSnapshotHoldsEachAnswerAndWhenItWasLastUsed(t *testing.T) {
t.Parallel()
synctest.Test(t, func(t *testing.T) {
_, clock, g := start()
placed := netip.MustParsePrefix("203.0.113.9/32")
notPlaced := netip.MustParsePrefix(unplaced + "/32")
asked := clock.Now()
wantCountry(t, g, placed, germany)
wantCountry(t, g, notPlaced, "")
clock.advance(time.Hour)
wantCountry(t, g, placed, germany)
want := []lookup.Answer{
{Client: notPlaced, Country: "", Answered: asked, Used: asked},
{Client: placed, Country: germany, Answered: asked, Used: asked.Add(time.Hour)},
}
if got := g.Snapshot(); !slices.Equal(got, want) {
t.Errorf("snapshot\n%+v\nwant\n%+v", got, want)
}
})
}
func TestLoadedAnswersAreKeptFor7DaysFromWhenGeoJSGaveThem(t *testing.T) {
t.Parallel()
geojs, clock, g := start()
now := clock.Now()
kept := lookup.Answer{
Client: netip.MustParsePrefix("203.0.113.9/32"),
Country: "FR",
Answered: now.Add(-week + time.Second),
Used: now.Add(-time.Hour),
}
stale := lookup.Answer{
Client: netip.MustParsePrefix("203.0.113.10/32"),
Country: "FR",
Answered: now.Add(-week),
Used: now.Add(-time.Hour),
}
g.Load([]lookup.Answer{kept, stale})
if got := g.Snapshot(); !slices.Equal(got, []lookup.Answer{kept}) {
t.Errorf("kept %+v, want only the answer GeoJS gave less than 7 days ago", got)
}
wantCountry(t, g, kept.Client, "FR")
wantRequests(t, geojs, 0)
}
func TestLoadDropsTheAnswerUsedLongestAgoFirst(t *testing.T) {
t.Parallel()
const maxAnswers = 100000
_, clock, g := start()
now := clock.Now()
// lookups.json lists the answers by client. Here each was last used a
// second before the one listed before it, so the last listed is the
// one used longest ago, and the one dropped.
answers := make([]lookup.Answer, maxAnswers+1)
addr := netip.MustParseAddr("10.0.0.0")
for i := range answers {
answers[i] = lookup.Answer{
Client: netip.PrefixFrom(addr, addr.BitLen()),
Country: germany,
Answered: now,
Used: now.Add(-time.Duration(i) * time.Second),
}
addr = addr.Next()
}
g.Load(answers)
got := g.Snapshot()
if len(got) != maxAnswers || got[0] != answers[0] ||
got[maxAnswers-1] != answers[maxAnswers-1] {
t.Errorf("%d answers kept, from %s to %s; want %d, from %s to %s",
len(got), got[0].Client, got[len(got)-1].Client, maxAnswers,
answers[0].Client, answers[maxAnswers-1].Client)
}
}
internal/metrics/countries.go
+116
View File
@@ -0,0 +1,116 @@
package metrics
import (
"sync"
"github.com/prometheus/client_golang/prometheus"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// other is the label under which the countries outside the busiest are
// counted.
const other = "other"
// countries are the metrics by the client's country, for requests whose
// client's country is known. The topN busiest countries, by their requests
// since the start, have series of their own, and the others are counted
// under other, so that there are never more than topN + 1 series. A
// country that drops out of the busiest loses its series, and its next
// requests are counted under other; one that becomes one of them gets a
// series that counts from then on. Each series therefore only ever goes
// up.
type countries struct {
topN int
requests *prometheus.CounterVec
requestBytes *prometheus.CounterVec
responseBytes *prometheus.CounterVec
// refused are the requests the country lists refused.
refused *prometheus.CounterVec
mu sync.Mutex
// seen is each country's requests since the start, by which the
// countries are ranked. GeoJS gives two-letter codes, so it holds at
// most a few hundred.
seen map[string]int64
// top are the countries with series of their own.
top map[string]bool
}
// newCountries returns the metrics by country, with series of their own
// for the topN busiest countries.
func newCountries(topN int) *countries {
byCountry := []string{"country"}
return &countries{
topN: topN,
requests: counterVec("smallwebwaf_country_requests_total",
"Requests, by the client's country.", byCountry),
requestBytes: counterVec("smallwebwaf_country_request_bytes_total",
"Request body bytes, by the client's country.", byCountry),
responseBytes: counterVec("smallwebwaf_country_response_bytes_total",
"Response body bytes, by the client's country.", byCountry),
refused: counterVec("smallwebwaf_country_list_refusals_total",
"Requests the country lists refused, by the client's country.",
byCountry),
seen: map[string]int64{},
top: map[string]bool{},
}
}
// add counts a request from its log line, whose country is known.
func (c *countries) add(line *requestlog.Line) {
c.mu.Lock()
defer c.mu.Unlock()
c.seen[line.Country]++
label := c.label(line.Country)
c.requests.WithLabelValues(label).Inc()
c.requestBytes.WithLabelValues(label).Add(float64(line.RequestBytes))
c.responseBytes.WithLabelValues(label).Add(float64(line.ResponseBytes))
if line.Action == requestlog.ActionCountryDenied {
c.refused.WithLabelValues(label).Inc()
}
}
// label returns the label a request from country is counted under: the
// country while it is one of the busiest, other while it is not. A
// country busier than the least busy of them takes its place, and that
// country's series are dropped.
func (c *countries) label(country string) string {
if c.top[country] {
return country
}
if len(c.top) < c.topN {
c.top[country] = true
return country
}
least := ""
for top := range c.top {
if least == "" || c.seen[top] < c.seen[least] {
least = top
}
}
if c.seen[country] <= c.seen[least] {
return other
}
delete(c.top, least)
for _, vec := range []*prometheus.CounterVec{
c.requests, c.requestBytes, c.responseBytes, c.refused,
} {
vec.DeleteLabelValues(least)
}
c.top[country] = true
return country
}
internal/metrics/metrics.go
+277
View File
@@ -0,0 +1,277 @@
// Package metrics keeps smallwebwaf's Prometheus metrics, as the "Metrics
// endpoint" section of SPEC.md lists them, and serves them in the
// Prometheus text format. No metric carries a client's address.
package metrics
import (
"net/http"
"strconv"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/collectors"
"github.com/prometheus/client_golang/prometheus/promhttp"
"sneak.berlin/go/smallwebwaf/internal/bans"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// Metrics are smallwebwaf's metrics. They are safe for concurrent use.
type Metrics struct {
registry *prometheus.Registry
handler http.Handler
inFlight prometheus.Gauge
requests *prometheus.CounterVec
requestBytes *prometheus.CounterVec
responseBytes *prometheus.CounterVec
requestDuration prometheus.Histogram
upstreamDuration prometheus.Histogram
rateLimitHits *prometheus.CounterVec
sizeAndTimeLimitHits *prometheus.CounterVec
offences *prometheus.CounterVec
countries *countries
// GeoJSRequests are the requests to GeoJS, and GeoJSFailures those
// that failed. GeoJSUnanswered are the requests whose client counted
// as coming from an unknown country because GeoJS had not answered
// about it in time.
GeoJSRequests prometheus.Counter
GeoJSFailures prometheus.Counter
GeoJSUnanswered prometheus.Counter
stateFileWrites *prometheus.CounterVec
stateFileWriteFailures *prometheus.CounterVec
stateFileLastWrite *prometheus.GaugeVec
stateFileSize *prometheus.GaugeVec
stateFileEditsTakenIn *prometheus.CounterVec
stateFileEditsSetAside *prometheus.CounterVec
}
// New returns the metrics, with the Go runtime's and the process's own.
// topN is how many countries get series of their own
// (SWWAF_METRICS_TOP_N).
func New(topN int) *Metrics {
byStatus := []string{"status_class", "action"}
byFile := []string{"file"}
m := &Metrics{
registry: prometheus.NewRegistry(),
inFlight: prometheus.NewGauge(prometheus.GaugeOpts{
Name: "smallwebwaf_requests_in_flight",
Help: "Requests under way.",
}),
requests: counterVec("smallwebwaf_requests_total",
"Requests, by the class of their status and their action.", byStatus),
requestBytes: counterVec("smallwebwaf_request_bytes_total",
"Request body bytes, by the class of the status and the action.",
byStatus),
responseBytes: counterVec("smallwebwaf_response_bytes_total",
"Response body bytes, by the class of the status and the action.",
byStatus),
requestDuration: prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "smallwebwaf_request_duration_seconds",
Help: "How long requests took, from their arrival to their end.",
}),
upstreamDuration: prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "smallwebwaf_upstream_duration_seconds",
Help: "How long requests passed to the app took, from then to their end.",
}),
rateLimitHits: counterVec("smallwebwaf_rate_limit_hits_total",
"Requests that broke a rate limit, by its window.",
[]string{"window"}),
sizeAndTimeLimitHits: counterVec("smallwebwaf_size_and_time_limit_hits_total",
"Requests that passed a size or time limit, by its setting.",
[]string{"limit"}),
offences: counterVec("smallwebwaf_offences_total",
"Offences, by kind.", []string{"kind"}),
countries: newCountries(topN),
GeoJSRequests: prometheus.NewCounter(prometheus.CounterOpts{
Name: "smallwebwaf_geojs_requests_total",
Help: "Requests to GeoJS.",
}),
GeoJSFailures: prometheus.NewCounter(prometheus.CounterOpts{
Name: "smallwebwaf_geojs_failures_total",
Help: "Requests to GeoJS that failed.",
}),
GeoJSUnanswered: prometheus.NewCounter(prometheus.CounterOpts{
Name: "smallwebwaf_geojs_unanswered_total",
Help: "Requests whose client counted as coming from an unknown " +
"country because GeoJS had not answered about it in time.",
}),
stateFileWrites: counterVec("smallwebwaf_state_file_writes_total",
"Writes of each state file.", byFile),
stateFileWriteFailures: counterVec("smallwebwaf_state_file_write_failures_total",
"Writes of each state file that failed.", byFile),
stateFileLastWrite: gaugeVec("smallwebwaf_state_file_last_write_timestamp_seconds",
"When each state file was last written, in seconds since 1970.", byFile),
stateFileSize: gaugeVec("smallwebwaf_state_file_size_bytes",
"The size of each state file, as it was last written.", byFile),
stateFileEditsTakenIn: counterVec("smallwebwaf_state_file_edits_taken_in_total",
"Edits of each state file taken in while running.", byFile),
stateFileEditsSetAside: counterVec("smallwebwaf_state_file_edits_set_aside_total",
"Edits of each state file renamed to <name>.bad because they did not parse.",
byFile),
}
m.handler = promhttp.HandlerFor(m.registry, promhttp.HandlerOpts{})
m.registry.MustRegister(
collectors.NewGoCollector(),
collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}),
m.inFlight, m.requests, m.requestBytes, m.responseBytes,
m.requestDuration, m.upstreamDuration,
m.rateLimitHits, m.sizeAndTimeLimitHits, m.offences,
m.countries.requests, m.countries.requestBytes, m.countries.responseBytes,
m.countries.refused,
m.GeoJSRequests, m.GeoJSFailures, m.GeoJSUnanswered,
m.stateFileWrites, m.stateFileWriteFailures,
m.stateFileLastWrite, m.stateFileSize,
m.stateFileEditsTakenIn, m.stateFileEditsSetAside,
)
return m
}
// AddBansAndClients adds the metrics read from the ledger and the table
// of clients as the metrics are asked for: the bans made since the start,
// the bans active and permanent at now, and the clients in the table.
func (m *Metrics) AddBansAndClients(
ledger *bans.Ledger, limiter *ratelimit.Limiter, now func() time.Time,
) {
m.registry.MustRegister(
// Every ban smallwebwaf makes so far is for a broken limit.
prometheus.NewCounterFunc(prometheus.CounterOpts{
Name: "smallwebwaf_bans_made_total",
Help: "Bans made, by cause.",
ConstLabels: prometheus.Labels{"cause": "limit"},
}, func() float64 {
return float64(ledger.Made())
}),
prometheus.NewGaugeFunc(prometheus.GaugeOpts{
Name: "smallwebwaf_active_bans",
Help: "Bans active now, the permanent ones included.",
}, func() float64 {
active, _ := ledger.Count(now())
return float64(active)
}),
prometheus.NewGaugeFunc(prometheus.GaugeOpts{
Name: "smallwebwaf_permanent_bans",
Help: "Permanent bans.",
}, func() float64 {
_, permanent := ledger.Count(now())
return float64(permanent)
}),
prometheus.NewGaugeFunc(prometheus.GaugeOpts{
Name: "smallwebwaf_tracked_clients",
Help: "Clients in the table of clients.",
}, func() float64 {
return float64(limiter.Len())
}),
)
}
// ServeHTTP answers with the metrics in the Prometheus text format.
func (m *Metrics) ServeHTTP(w http.ResponseWriter, r *http.Request) {
m.handler.ServeHTTP(w, r)
}
// RequestStarted counts a request as under way.
func (m *Metrics) RequestStarted() {
m.inFlight.Inc()
}
// RequestEnded counts a request that has ended, from its log line. limit
// is the setting whose size or time limit the request passed, "" if none.
// duration is how long the request took, and upstreamDuration how long it
// took from when it was passed to the app, zero if it was not.
func (m *Metrics) RequestEnded(
line *requestlog.Line, limit string, duration, upstreamDuration time.Duration,
) {
m.inFlight.Dec()
class := statusClass(line.Status)
m.requests.WithLabelValues(class, line.Action).Inc()
m.requestBytes.WithLabelValues(class, line.Action).Add(float64(line.RequestBytes))
m.responseBytes.WithLabelValues(class, line.Action).Add(float64(line.ResponseBytes))
m.requestDuration.Observe(duration.Seconds())
if upstreamDuration > 0 {
m.upstreamDuration.Observe(upstreamDuration.Seconds())
}
if line.LimitHit != "" {
m.rateLimitHits.WithLabelValues(line.LimitHit).Inc()
}
if limit != "" {
m.sizeAndTimeLimitHits.WithLabelValues(limit).Inc()
}
if line.Offence != "" {
m.offences.WithLabelValues(line.Offence).Inc()
}
if line.Country != "" {
m.countries.add(line)
}
}
// StateFileWritten counts a write of the state file name, of size bytes,
// that ended with err.
func (m *Metrics) StateFileWritten(name string, size int, err error) {
m.stateFileWrites.WithLabelValues(name).Inc()
// The series of failures is there from the first write, at zero until
// one fails.
failures := m.stateFileWriteFailures.WithLabelValues(name)
if err != nil {
failures.Inc()
return
}
m.stateFileLastWrite.WithLabelValues(name).SetToCurrentTime()
m.stateFileSize.WithLabelValues(name).Set(float64(size))
}
// StateFileEditTakenIn counts an admin's edit of the state file name
// taken in while smallwebwaf runs.
func (m *Metrics) StateFileEditTakenIn(name string) {
m.stateFileEditsTakenIn.WithLabelValues(name).Inc()
}
// StateFileEditSetAside counts an admin's edit of the state file name
// renamed to name.bad because it did not parse.
func (m *Metrics) StateFileEditSetAside(name string) {
m.stateFileEditsSetAside.WithLabelValues(name).Inc()
}
// statusClass returns the class of status, such as 2xx, or none when no
// status was sent.
func statusClass(status int) string {
if status == 0 {
return "none"
}
// A status's class is its hundreds: 404 is in 4xx.
const hundred = 100
return strconv.Itoa(status/hundred) + "xx"
}
// counterVec returns a counter named name, described by help, with a
// series for each set of values of labels.
func counterVec(name, help string, labels []string) *prometheus.CounterVec {
return prometheus.NewCounterVec(prometheus.CounterOpts{Name: name, Help: help},
labels)
}
// gaugeVec returns a gauge named name, described by help, with a series
// for each set of values of labels.
func gaugeVec(name, help string, labels []string) *prometheus.GaugeVec {
return prometheus.NewGaugeVec(prometheus.GaugeOpts{Name: name, Help: help}, labels)
}
internal/proxy/admin.go
+43
View File
@@ -0,0 +1,43 @@
package proxy
import (
"crypto/subtle"
"net/http"
"strings"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// answerAdmin answers a request for smallwebwaf itself, under
// /_smallwebwaf/, once it has passed the checks: GET MetricsPath with
// SWWAF_METRICS_TOKEN gets the metrics, and without it is refused with
// 401. Any other request gets 404, as the metrics do while
// SWWAF_METRICS_TOKEN is unset.
func (rq *request) answerAdmin() {
rq.line.Action = requestlog.ActionAdmin
rq.startClientResponseTimeout()
token := rq.h.config.MetricsToken
switch {
case token == "" || rq.in.Method != http.MethodGet || rq.in.URL.Path != MetricsPath:
http.Error(rq.out, http.StatusText(http.StatusNotFound), http.StatusNotFound)
case !hasToken(rq.in, token):
rq.out.Header().Set("WWW-Authenticate", "Bearer")
rq.answer(refusal{
status: http.StatusUnauthorized,
action: requestlog.ActionAdmin,
})
default:
rq.h.metrics.ServeHTTP(rq.out, rq.in)
}
}
// hasToken reports whether r carries token, as Authorization: Bearer
// <token>.
func hasToken(r *http.Request, token string) bool {
scheme, sent, _ := strings.Cut(r.Header.Get("Authorization"), " ")
return strings.EqualFold(scheme, "Bearer") &&
subtle.ConstantTimeCompare([]byte(sent), []byte(token)) == 1
}
internal/proxy/bans.go
+98
View File
@@ -0,0 +1,98 @@
package proxy
import (
"net/netip"
"time"
"sneak.berlin/go/smallwebwaf/internal/bans"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// banResponse is a refusal answered with SWWAF_BAN_RESPONSE, and logged
// with action.
func (rq *request) banResponse(action string) *refusal {
return &refusal{status: rq.h.config.BanResponse, action: action}
}
// banned reports whether a ban on a netblock the client is in covers the
// request at now, and notes for the log line when that ban ends.
func (rq *request) banned(now time.Time) bool {
check := rq.h.ledger.Check
if rq.h.config.Observe {
check = rq.h.ledger.Find // in observe mode the ban refuses nothing
}
ban, banned := check(rq.client, now)
if banned {
rq.line.BanExpires = banExpires(ban)
}
return banned
}
// limitBroken counts the request for the rate limits at now, notes the
// client's counts for the log line, and reports whether the request takes
// the client over a limit. In enforce mode such a request bans the
// client's netblock, and sets the client's counters back to zero; in
// observe mode it does neither.
func (rq *request) limitBroken(now time.Time) bool {
group := clientGroup(rq.client)
counts, hit, over := rq.h.limiter.Count(group, now)
rq.line.Counts = counts
if !over {
return false
}
rq.line.LimitHit = hit.Window
rq.line.Offence = requestlog.OffenceLimit
if rq.h.config.Observe {
return true
}
netblock := rq.netblock()
ban := rq.h.ledger.BanForLimit(netblock, now, bans.Notes{
Country: rq.line.Country,
Limit: hit.Limit,
Window: hit.Window,
Count: hit.Requests,
Request: bans.Request{
Time: now,
Method: rq.in.Method,
Host: rq.in.Host,
Path: rq.in.URL.RequestURI(),
Status: rq.h.config.BanResponse,
UserAgent: rq.in.UserAgent(),
},
// The histories count this request only once it has ended.
Requests: rq.h.limiter.Requests(netblock) + 1,
})
rq.h.limiter.Reset(group)
rq.line.BanExpires = banExpires(ban)
return true
}
// netblock is the netblock a ban on the client covers: its IPv4 address,
// widened to SWWAF_BAN_SCOPE_V4_PREFIX, or the IPv6 group clientGroup
// counts it in.
func (rq *request) netblock() netip.Prefix {
addr := rq.client.Unmap()
if addr.Is4() {
return netip.PrefixFrom(addr, rq.h.config.BanScopeV4Prefix).Masked()
}
return clientGroup(addr)
}
// banExpires is when ban ends, as the log line gives it: a time, or
// permanent.
func banExpires(ban bans.Ban) string {
if ban.Permanent() {
return "permanent"
}
return requestlog.FormatTime(ban.Expires)
}
internal/proxy/bans_test.go
+455
View File
@@ -0,0 +1,455 @@
package proxy_test
import (
"bufio"
"errors"
"io"
"maps"
"net/http"
"net/netip"
"slices"
"sync"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/bans"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
const (
// otherClient is a client next to client.
otherClient = "203.0.113.10"
// userAgent is the user agent of every request a sender sends.
userAgent = "ban-test/1.0"
// permanent is the log line's ban_expires for a permanent ban.
permanent = "permanent"
)
func TestBrokenLimitBansTheClient(t *testing.T) {
t.Parallel()
s, clk, _ := startWithClock(t, "", map[string]string{rateLimitPerMinute: "1"})
expires := requestlog.FormatTime(clk.Now().Add(time.Hour))
// The request over the limit of one a minute is refused, and bans the
// client for an hour, the default.
s.get(client, http.StatusOK, requestlog.ActionForward)
line := s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
if line.LimitHit != minute || line.Offence != requestlog.OffenceLimit ||
line.BanExpires != expires {
t.Errorf("log line has limit_hit %q, offence %q and ban_expires %q, "+
"want minute, limit and %s", line.LimitHit, line.Offence, line.BanExpires,
expires)
}
// Every request while the ban lasts is refused.
clk.advance(time.Hour - time.Second)
line = s.get(client, http.StatusForbidden, requestlog.ActionBanned)
if line.BanExpires != expires || line.Offence != "" || line.LimitHit != "" {
t.Errorf("log line has ban_expires %q, offence %q and limit_hit %q, "+
"want %s and neither of the others", line.BanExpires, line.Offence,
line.LimitHit, expires)
}
// Once it ends, the client is let through.
clk.advance(time.Second)
s.get(client, http.StatusOK, requestlog.ActionForward)
}
func TestBanLengthsFollowTheSettings(t *testing.T) {
t.Parallel()
s, clk, _ := startWithClock(t, "", map[string]string{
rateLimitPerMinute: "1",
limitBanDuration: "10m",
limitBanRepeatWindow: "1h",
maxBanDuration: "1h",
})
// breakLimit has client go over the limit of one a minute, and
// returns when the ban that makes ends.
breakLimit := func() string {
s.get(client, http.StatusOK, requestlog.ActionForward)
return s.get(client, http.StatusForbidden, requestlog.ActionRateLimited).BanExpires
}
wantExpires := func(got string, length time.Duration) {
t.Helper()
want := requestlog.FormatTime(clk.Now().Add(length))
if got != want {
t.Errorf("ban ends at %s, want %s", got, want)
}
}
// A first ban lasts SWWAF_LIMIT_BAN_DURATION; one within
// SWWAF_LIMIT_BAN_REPEAT_WINDOW after it ended, three times as long.
wantExpires(breakLimit(), 10*time.Minute)
clk.advance(10*time.Minute + time.Hour)
wantExpires(breakLimit(), 30*time.Minute)
// Later than that, SWWAF_LIMIT_BAN_DURATION again.
clk.advance(30*time.Minute + time.Hour + time.Second)
wantExpires(breakLimit(), 10*time.Minute)
clk.advance(10 * time.Minute)
wantExpires(breakLimit(), 30*time.Minute)
// 90 minutes would be longer than SWWAF_MAX_BAN_DURATION: the ban is
// permanent.
clk.advance(30 * time.Minute)
got := breakLimit()
if got != permanent {
t.Errorf("ban ends at %s, want a permanent one", got)
}
clk.advance(365 * 24 * time.Hour)
s.get(client, http.StatusForbidden, requestlog.ActionBanned)
}
func TestBanIsNotCountedAndResetsTheCounters(t *testing.T) {
t.Parallel()
s, clk, server := startWithClock(t, "", map[string]string{rateLimitPerDay: "2"})
// The third request in a day is over the limit of two, and bans the
// client for an hour.
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
for range 3 {
s.get(client, http.StatusForbidden, requestlog.ActionBanned)
}
// Later the same day the client has its whole allowance again: the
// ban set its counters back to zero, and the requests it refused were
// not counted for the rate limits, only in its notes.
clk.advance(time.Hour)
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
banned := server.Ledger.Bans(netip.MustParsePrefix(client + "/32"))
if len(banned) != 2 || banned[0].Notes.Refused != 3 {
t.Errorf("bans %+v, want two, the first with 3 requests refused", banned)
}
}
func TestBanCoversTheClientsNetblock(t *testing.T) {
t.Parallel()
// In the IPv4 cases, client breaks the limit; these two are next to it.
const (
allowed = "203.0.113.60" // in SWWAF_ALLOW_NETS
exempt = "203.0.113.50" // in SWWAF_RATE_LIMIT_EXEMPT_NETS
)
for _, tc := range []struct {
name string
env map[string]string
breaker string // the client that breaks the limit
refused []string
let []string // let through
}{
{
"an IPv4 address, by default", nil, client,
nil, []string{otherClient, exempt},
},
{
"the IPv4 netblock SWWAF_BAN_SCOPE_V4_PREFIX sets",
map[string]string{banScopeV4Prefix: "24"}, client,
[]string{otherClient, exempt}, []string{"203.0.112.9", allowed},
},
{
"an IPv6 /64", nil, "2001:db8:5::1",
[]string{"2001:db8:5::ffff:1"}, []string{"2001:db8:5:1::1"},
},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
env := map[string]string{
rateLimitPerMinute: "1",
allowNets: allowed,
rateLimitExemptNets: exempt,
}
maps.Copy(env, tc.env)
s, _, _ := startWithClock(t, "", env)
s.get(tc.breaker, http.StatusOK, requestlog.ActionForward)
s.get(tc.breaker, http.StatusForbidden, requestlog.ActionRateLimited)
for _, sent := range tc.refused {
s.get(sent, http.StatusForbidden, requestlog.ActionBanned)
}
for _, sent := range tc.let {
s.get(sent, http.StatusOK, requestlog.ActionForward)
}
})
}
}
func TestBannedClientIsRefusedBeforeItsCountryIsLookedUp(t *testing.T) {
t.Parallel()
geojsURL, asked := startGeoJS(t)
s, _, _ := startWithClock(t, geojsURL, map[string]string{
rateLimitPerMinute: "1",
banScopeV4Prefix: "24",
deniedCountries: "kp",
})
// fromDE's ban covers otherClient, which is refused unasked about.
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
line := s.get(otherClient, http.StatusForbidden, requestlog.ActionBanned)
if line.Country != "" {
t.Errorf("log line has country %q, want none", line.Country)
}
if !slices.Equal(asked(), []string{fromDE}) {
t.Errorf("GeoJS was asked about %v, want %s alone", asked(), fromDE)
}
}
func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
t.Parallel()
const denied = "192.0.2.50" // in SWWAF_DENY_NETS
for _, tc := range []struct {
setting string // "" leaves SWWAF_BAN_RESPONSE at its default
status int // 0 is the connection closed without an answer
}{
{"", http.StatusForbidden},
{"403", http.StatusForbidden},
{"429", http.StatusTooManyRequests},
{"close", 0},
} {
t.Run(banResponse+"="+tc.setting, func(t *testing.T) {
t.Parallel()
geojsURL, _ := startGeoJS(t)
env := map[string]string{
rateLimitPerMinute: "1",
denyNets: denied,
deniedCountries: "kp",
}
if tc.setting != "" {
env[banResponse] = tc.setting
}
s, _, _ := startWithClock(t, geojsURL, env)
s.get(denied, tc.status, requestlog.ActionDenied)
s.get(fromKP, tc.status, requestlog.ActionCountryDenied)
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
s.get(fromDE, tc.status, requestlog.ActionRateLimited)
s.get(fromDE, tc.status, requestlog.ActionBanned)
})
}
}
func TestBanNotes(t *testing.T) {
t.Parallel()
geojsURL, _ := startGeoJS(t)
s, clk, server := startWithClock(t, geojsURL, map[string]string{
rateLimitPerMinute: "1",
deniedCountries: "kp",
})
start := clk.Now()
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
s.request(fromDE, "/repo/commits?page=2",
http.StatusForbidden, requestlog.ActionRateLimited)
s.get(fromDE, http.StatusForbidden, requestlog.ActionBanned)
s.get(fromDE, http.StatusForbidden, requestlog.ActionBanned)
netblock := netip.MustParsePrefix(fromDE + "/32")
want := bans.Ban{
Netblock: netblock,
Start: start,
Expires: start.Add(time.Hour),
Notes: bans.Notes{
Country: "DE",
Limit: 1,
Window: minute,
Count: 2,
Request: bans.Request{
Time: start,
Method: http.MethodGet,
Host: appHost,
Path: "/repo/commits?page=2",
Status: http.StatusForbidden,
UserAgent: userAgent,
},
// The one let through, the one that broke the limit and the two
// refused under the ban.
Requests: 4,
Refused: 2,
EarlierBans: 0,
},
}
ledger := server.Ledger
got := ledger.Bans(netblock)
if len(got) != 1 || got[0] != want {
t.Fatalf("bans\n%+v\nwant\n%+v", got, want)
}
// The next ban counts this one among the earlier.
clk.advance(time.Hour)
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
got = ledger.Bans(netblock)
if len(got) != 2 || got[1].Notes.EarlierBans != 1 {
t.Errorf("bans %+v, want two, the second with one earlier ban", got)
}
}
func TestMaxBansDropsTheBanOfTheNetblockSeenLongestAgo(t *testing.T) {
t.Parallel()
s, _, _ := startWithClock(t, "", map[string]string{
rateLimitPerMinute: "1",
maxBans: "1",
})
// One ban is held, so otherClient's ban drops client's.
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
s.get(otherClient, http.StatusOK, requestlog.ActionForward)
s.get(otherClient, http.StatusForbidden, requestlog.ActionRateLimited)
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(otherClient, http.StatusForbidden, requestlog.ActionBanned)
}
// clock is the time a test sets, by which smallwebwaf counts requests and
// makes bans.
type clock struct {
mu sync.Mutex
now time.Time
}
// Now tells the time.
func (c *clock) Now() time.Time {
c.mu.Lock()
defer c.mu.Unlock()
return c.now
}
// advance moves the clock on by d.
func (c *clock) advance(d time.Duration) {
c.mu.Lock()
defer c.mu.Unlock()
c.now = c.now.Add(d)
}
// startWithClock starts smallwebwaf in front of an app that answers 200,
// with the settings in env on top of trusting localhost's
// X-Forwarded-For, clients' countries looked up at geojsURL, and a clock
// set to midnight, the start of a bucket in every window.
func startWithClock(
t *testing.T, geojsURL string, env map[string]string,
) (*sender, *clock, *proxy.Server) {
t.Helper()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
clk := &clock{now: time.Date(2026, 10, 6, 0, 0, 0, 0, time.UTC)}
settings := map[string]string{trustedProxies: trustLocalhost}
maps.Copy(settings, env)
addr, out, server := startProxyWithClock(t, app.URL, geojsURL, clk.Now, settings)
return &sender{t: t, addr: addr, out: out}, clk, server
}
// sender sends requests to smallwebwaf one after another, each on a
// connection of its own, and checks each one's answer and log line. They
// must be the only requests smallwebwaf is sent, since the log lines are
// matched to them in order.
type sender struct {
t *testing.T
addr string
out *output
sent int
}
// get sends a GET request for / from the client at from.
func (s *sender) get(from string, status int, action string) logLine {
s.t.Helper()
return s.request(from, "/", status, action)
}
// request sends a GET request for path from the client at from, as
// X-Forwarded-For names it, and checks that its answer and its log line
// have status, 0 for the connection closed without an answer, and that
// the line has action. It returns the log line.
func (s *sender) request(from, path string, status int, action string) logLine {
s.t.Helper()
line, _ := s.requestWithHeader(from, path, "", status, action)
return line
}
// requestWithHeader is request with header, such as "Authorization:
// Bearer x", added to the request unless it is "". It returns the body of
// the answer too.
func (s *sender) requestWithHeader(
from, path, header string, status int, action string,
) (logLine, string) {
s.t.Helper()
if header != "" {
header += "\r\n"
}
conn := dial(s.t, s.addr)
send(s.t, conn, "GET "+path+" HTTP/1.1\r\nHost: "+appHost+
"\r\nUser-Agent: "+userAgent+"\r\n"+forwardedFor+": "+from+"\r\n"+
header+"\r\n")
err := conn.SetReadDeadline(time.Now().Add(waitLimit))
if err != nil {
s.t.Fatalf("set read deadline: %v", err)
}
var got answer
res, err := http.ReadResponse(bufio.NewReader(conn), nil)
switch {
case err == nil:
got = readAnswer(res)
case !errors.Is(err, io.ErrUnexpectedEOF):
s.t.Fatalf("read response: %v", err)
}
_ = conn.Close()
if got.status != status {
s.t.Errorf("request %d, from %s: status %d, want %d", s.sent+1, from,
got.status, status)
}
line := s.out.requestLines(s.t, s.sent+1)[s.sent]
s.sent++
wantLine(s.t, line, status, action)
return line, string(got.body)
}
internal/proxy/bodies.go
+2
View File
@@ -46,6 +46,7 @@ func (b *requestBody) Read(p []byte) (int, error) {
b.rq.refuse(refusal{
status: http.StatusRequestEntityTooLarge,
action: requestlog.ActionTooLarge,
limit: "SWWAF_REQUEST_MAX_BYTES",
})
}
@@ -81,6 +82,7 @@ func (b *responseBody) Read(p []byte) (int, error) {
b.rq.refuse(refusal{
status: http.StatusBadGateway,
action: requestlog.ActionTooLarge,
limit: "SWWAF_RESPONSE_MAX_BYTES",
})
return n, errResponseTooLarge
internal/proxy/client.go
+28
View File
@@ -1,6 +1,7 @@
package proxy
import (
"crypto/rand"
"net/http"
"net/netip"
"slices"
@@ -48,6 +49,33 @@ func clientAddress(
return client
}
// requestIDHeader carries the request's id, from traefik and to the app.
const requestIDHeader = "X-Request-ID"
// requestID is the request's id: the one a trusted proxy sent, or a new
// random one. A peer outside the trusted proxies did not come through
// traefik, so the id it sends is its own claim, and is replaced.
func requestID(r *http.Request, peerTrusted bool) string {
id := r.Header.Get(requestIDHeader)
if !peerTrusted || id == "" {
id = rand.Text()
}
return id
}
// scheme is how the client reached traefik, as a trusted proxy says in
// X-Forwarded-Proto, or otherwise http, the only scheme smallwebwaf
// serves.
func scheme(r *http.Request, peerTrusted bool) string {
proto := r.Header.Get("X-Forwarded-Proto")
if !peerTrusted || proto == "" {
return "http"
}
return proto
}
// ipv6GroupPrefix is the length of the IPv6 netblock that is one client.
const ipv6GroupPrefix = 64
internal/proxy/client_test.go
+18 -14
View File
@@ -14,10 +14,14 @@ const (
appHost = "app.example"
// client is the client's address, as a proxy names it.
client = "203.0.113.9"
// forwardedFor is the header that lists the client and its proxies.
forwardedFor = "X-Forwarded-For"
// secure is the scheme a client reached traefik with.
// forwardedFor is the header that lists the client and its proxies,
// and forwardedProto the one that gives the scheme the client used.
forwardedFor = "X-Forwarded-For"
forwardedProto = "X-Forwarded-Proto"
// secure is the scheme a client reached traefik with, and plain the
// one smallwebwaf serves.
secure = "https"
plain = "http"
)
// appHeaders is what the app tells about the headers it received.
@@ -65,13 +69,13 @@ func TestClientAddressAndForwardedHeaders(t *testing.T) {
func clientAddressCases() []clientAddressCase {
trusted := map[string]string{trustedProxies: trustLocalhost}
forged := http.Header{
forwardedFor: {client},
"X-Forwarded-Host": {"forged.example"},
"X-Forwarded-Proto": {secure},
"X-Real-Ip": {client},
forwardedFor: {client},
"X-Forwarded-Host": {"forged.example"},
forwardedProto: {secure},
"X-Real-Ip": {client},
}
replaced := appHeaders{
ForwardedFor: localhost, ForwardedHost: appHost, ForwardedProto: "http",
ForwardedFor: localhost, ForwardedHost: appHost, ForwardedProto: plain,
}
return []clientAddressCase{{
@@ -87,10 +91,10 @@ func clientAddressCases() []clientAddressCase {
"outside the trusted proxies from the right",
env: trusted,
header: http.Header{
forwardedFor: {"198.51.100.7, " + client + ", 10.0.0.2"},
"X-Forwarded-Host": {appHost},
"X-Forwarded-Proto": {secure},
"X-Real-Ip": {client},
forwardedFor: {"198.51.100.7, " + client + ", 10.0.0.2"},
"X-Forwarded-Host": {appHost},
forwardedProto: {secure},
"X-Real-Ip": {client},
},
wantClient: client,
wantApp: appHeaders{
@@ -138,8 +142,8 @@ func requestWithHeaders(
Host: r.Host,
ForwardedFor: r.Header.Get(forwardedFor),
ForwardedHost: r.Header.Get("X-Forwarded-Host"),
ForwardedProto: r.Header.Get("X-Forwarded-Proto"),
RealIP: r.Header.Get("X-Real-Ip"),
ForwardedProto: r.Header.Get(forwardedProto),
RealIP: r.Header.Get("X-Real-IP"),
})
})
addr, out := startProxy(t, app.URL, env)
internal/proxy/countries.go
+41
View File
@@ -0,0 +1,41 @@
package proxy
import (
"context"
"net/netip"
"slices"
)
// countryDenied reports whether the country lists refuse the request.
// The client's country is looked up only while a list is set, and never
// for a client on a private, loopback or link-local address, which has
// no country. A client without a country, or whose country cannot be
// found, is refused only by SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES. ctx is
// the request's own context.
func (rq *request) countryDenied(ctx context.Context) bool {
denied := rq.h.config.DeniedCountries
allowed := rq.h.config.ExclusivelyAllowedCountries
if len(denied) == 0 && len(allowed) == 0 {
return false
}
var country string
if hasCountry(rq.client) {
country = rq.h.geojs.Country(ctx, clientGroup(rq.client))
}
rq.line.Country = country
if slices.Contains(denied, country) {
return true
}
return len(allowed) > 0 && !slices.Contains(allowed, country)
}
// hasCountry reports whether addr can be placed in a country: private,
// loopback and link-local addresses cannot.
func hasCountry(addr netip.Addr) bool {
return !addr.IsPrivate() && !addr.IsLoopback() && !addr.IsLinkLocalUnicast()
}
internal/proxy/countries_test.go
+308
View File
@@ -0,0 +1,308 @@
package proxy_test
import (
"encoding/json"
"maps"
"net/http"
"net/http/httptest"
"slices"
"strings"
"sync"
"sync/atomic"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// The clients the stand-in for GeoJS knows about.
const (
// fromDE is placed in Germany.
fromDE = client
// fromKP is placed in North Korea.
fromKP = "198.51.100.7"
// unplaced cannot be placed in any country.
unplaced = "192.0.2.1"
)
func TestCountryLists(t *testing.T) {
t.Parallel()
for _, tc := range []struct {
name string
env map[string]string
refused []string
}{
{"denied", map[string]string{deniedCountries: "kp"}, []string{fromKP}},
{
"exclusively allowed", map[string]string{allowedCountries: "DE"},
[]string{fromKP, unplaced},
},
{
"both", map[string]string{deniedCountries: "kp", allowedCountries: "de,fr"},
[]string{fromKP, unplaced},
},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
geojsURL, _ := startGeoJS(t)
env := map[string]string{trustedProxies: trustLocalhost}
maps.Copy(env, tc.env)
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, env)
for i, sent := range []struct{ client, country string }{
{fromDE, "DE"}, {fromKP, "KP"}, {unplaced, ""},
} {
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
req.Header.Set(forwardedFor, sent.client)
got := do(t, req)
line := out.requestLines(t, i+1)[i]
if line.Country != sent.country {
t.Errorf("log line has country %q, want %q", line.Country, sent.country)
}
if slices.Contains(tc.refused, sent.client) {
wantStatus(t, got, http.StatusForbidden)
wantLine(t, line, http.StatusForbidden, requestlog.ActionCountryDenied)
} else {
wantStatus(t, got, http.StatusOK)
wantLine(t, line, http.StatusOK, requestlog.ActionForward)
}
}
if int(calls.Load()) != 3-len(tc.refused) {
t.Errorf("the app was called %d times, want %d",
calls.Load(), 3-len(tc.refused))
}
})
}
}
func TestCountryRefusalComesBeforeTheBody(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
geojsURL, _ := startGeoJS(t)
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
trustedProxies: trustLocalhost,
deniedCountries: "kp",
})
req := newRequest(t, http.MethodPost, addr, "/", strings.NewReader("a body"))
req.Header.Set(forwardedFor, fromKP)
wantStatus(t, do(t, req), http.StatusForbidden)
line := out.requestLine(t)
wantLine(t, line, http.StatusForbidden, requestlog.ActionCountryDenied)
if line.RequestBytes != 0 {
t.Errorf("log line has request_bytes %d, want 0", line.RequestBytes)
}
if calls.Load() != 0 {
t.Errorf("the app was called %d times, want none", calls.Load())
}
}
func TestRequestRefusedByCountryIsNotCounted(t *testing.T) {
t.Parallel()
// The stand-in for GeoJS fails until placing is set, and then places
// every address in Germany.
var placing atomic.Bool
geojs := httptest.NewServer(http.HandlerFunc(
func(w http.ResponseWriter, r *http.Request) {
if !placing.Load() {
w.WriteHeader(http.StatusServiceUnavailable)
return
}
answer := []map[string]string{{"ip": r.URL.Query().Get("ip"), "country": "DE"}}
err := json.NewEncoder(w).Encode(answer)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}))
t.Cleanup(geojs.Close)
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, _ := startProxyWithGeoJS(t, app.URL, geojs.URL, map[string]string{
trustedProxies: trustLocalhost,
allowedCountries: "de",
rateLimitPerMinute: "1",
})
request := func() answer {
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
req.Header.Set(forwardedFor, fromDE)
return do(t, req)
}
// While GeoJS fails, the client's country cannot be found, and its
// request is refused.
wantStatus(t, request(), http.StatusForbidden)
// Once GeoJS places it, a second after the failure, its requests are let
// through. No refused one was counted, so the first let through is
// within the limit of one a minute.
placing.Store(true)
deadline := time.Now().Add(waitLimit)
got := request()
for got.status == http.StatusForbidden && time.Now().Before(deadline) {
time.Sleep(pollInterval)
got = request()
}
wantStatus(t, got, http.StatusOK)
}
func TestCountryNotLookedUpWithoutAListOrForAPrivateAddress(t *testing.T) {
t.Parallel()
for _, tc := range []struct {
name string
env map[string]string
clients []string // "" sends no X-Forwarded-For: the client is 127.0.0.1
}{
{"no country list is set", nil, []string{fromKP, fromDE}},
{
"private, loopback and link-local addresses",
map[string]string{deniedCountries: "kp"},
[]string{"10.0.0.5", "192.168.1.9", "fd00::5", "", "169.254.0.9", "fe80::9"},
},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
geojsURL, asked := startGeoJS(t)
env := map[string]string{trustedProxies: trustLocalhost}
maps.Copy(env, tc.env)
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, env)
for i, sent := range tc.clients {
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
if sent != "" {
req.Header.Set(forwardedFor, sent)
}
wantStatus(t, do(t, req), http.StatusOK)
line := out.requestLines(t, i+1)[i]
wantLine(t, line, http.StatusOK, requestlog.ActionForward)
country, present := line.fields["country"]
if !present || country != "" {
t.Errorf("log line for %q has country %v, want an empty one",
line.ClientIP, country)
}
}
if len(asked()) != 0 {
t.Errorf("GeoJS was asked about %v, want nothing", asked())
}
})
}
}
func TestExclusiveListRefusesAPrivateAddressUnlessAllowed(t *testing.T) {
t.Parallel()
for _, tc := range []struct {
name string
allowNets string
status int
action string
}{
{
"not in SWWAF_ALLOW_NETS", "",
http.StatusForbidden, requestlog.ActionCountryDenied,
},
{
"in SWWAF_ALLOW_NETS", "10.0.0.7,fd00::/8",
http.StatusOK, requestlog.ActionForward,
},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
geojsURL, asked := startGeoJS(t)
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
trustedProxies: trustLocalhost,
allowedCountries: "de",
allowNets: tc.allowNets,
})
wantAnswers(t, addr, out, []sentRequest{
{"10.0.0.7", tc.status, tc.action},
{"fd00::5", tc.status, tc.action},
})
if len(asked()) != 0 {
t.Errorf("GeoJS was asked about %v, want nothing", asked())
}
})
}
}
// startGeoJS starts a stand-in for GeoJS, which places fromDE and fromKP
// and no other address. It returns its URL, and what returns the
// addresses it has been asked about.
func startGeoJS(t *testing.T) (string, func() []string) {
t.Helper()
places := map[string]string{fromDE: "DE", fromKP: "KP"}
var asked struct {
mu sync.Mutex
addrs []string
}
geojs := httptest.NewServer(http.HandlerFunc(
func(w http.ResponseWriter, r *http.Request) {
addrs := strings.Split(r.URL.Query().Get("ip"), ",")
asked.mu.Lock()
asked.addrs = append(asked.addrs, addrs...)
asked.mu.Unlock()
answers := make([]map[string]string, 0, len(addrs))
for _, addr := range addrs {
answers = append(answers, map[string]string{
"ip": addr, "country": places[addr],
})
}
err := json.NewEncoder(w).Encode(answers)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}))
t.Cleanup(geojs.Close)
return geojs.URL, func() []string {
asked.mu.Lock()
defer asked.mu.Unlock()
return slices.Clone(asked.addrs)
}
}
internal/proxy/health_test.go
+56
View File
@@ -0,0 +1,56 @@
package proxy_test
import (
"net/http"
"sync/atomic"
"testing"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
func TestHealthEndpointIsAnsweredBeforeAnyCheck(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
// With a limit of one request a minute, any request counted before
// the last one would have it refused.
addr, out := startProxy(t, app.URL, map[string]string{rateLimitPerMinute: "1"})
const (
healthChecks = 3
contentType = "text/plain; charset=utf-8"
)
for range healthChecks {
got := get(t, addr, proxy.HealthPath)
wantStatus(t, got, http.StatusOK)
if string(got.body) != "ok\n" || got.header.Get("Content-Type") != contentType {
t.Errorf("health endpoint answered %q with Content-Type %q, want ok "+
"with %q", got.body, got.header.Get("Content-Type"), contentType)
}
}
wantStatus(t, get(t, addr, "/"), http.StatusOK)
lines := out.requestLines(t, healthChecks+1)
for _, line := range lines[:healthChecks] {
wantLine(t, line, http.StatusOK, requestlog.ActionAdmin)
if line.ResponseContentType != contentType {
t.Errorf("health check's log line has response_content_type %q, "+
"want %q", line.ResponseContentType, contentType)
}
}
wantLine(t, lines[healthChecks], http.StatusOK, requestlog.ActionForward)
if calls.Load() != 1 {
t.Errorf("the app was called %d times, want once", calls.Load())
}
}
internal/proxy/history_test.go
+124
View File
@@ -0,0 +1,124 @@
package proxy_test
import (
"io"
"net/http"
"net/netip"
"strings"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
func TestHistoryKeepsEachRequestOfTheClient(t *testing.T) {
t.Parallel()
geojsURL, _ := startGeoJS(t)
s, clk, server := startWithClock(t, geojsURL, map[string]string{
rateLimitPerMinute: "2",
deniedCountries: "kp",
})
start := clk.Now()
// Two let through, one over the limit, which bans the client, and one
// refused under that ban, for which the country is not looked up.
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
clk.advance(time.Second)
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
clk.advance(time.Second)
s.get(fromDE, http.StatusForbidden, requestlog.ActionBanned)
want := ratelimit.History{
FirstSeen: start,
LastSeen: start.Add(2 * time.Second),
Country: "DE",
LookedUp: start.Add(time.Second),
Requests: 4,
Forwarded: 2,
Refused: 2,
// The app answers with no body, smallwebwaf with its status text.
ResponseBytes: 2 * int64(len("Forbidden\n")),
Responses: ratelimit.Responses{Status2xx: 2, Status4xx: 2},
Offences: ratelimit.Offences{Limit: 1},
}
got := historyOf(t, server, fromDE)
if got != want {
t.Errorf("history\n%+v\nwant\n%+v", got, want)
}
}
func TestHistoryCountsTheBodiesEachWay(t *testing.T) {
t.Parallel()
app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
_, _ = io.Copy(io.Discard, r.Body)
_, _ = io.WriteString(w, "hello")
})
addr, out, server := startProxyWithClock(t, app.URL, "", time.Now, nil)
got := do(t, newRequest(t, http.MethodPost, addr, "/", strings.NewReader("abc")))
wantStatus(t, got, http.StatusOK)
out.requestLine(t)
history := historyOf(t, server, localhost)
if history.RequestBytes != 3 || history.ResponseBytes != 5 {
t.Errorf("history counts %d bytes in and %d out, want 3 and 5",
history.RequestBytes, history.ResponseBytes)
}
}
func TestHealthEndpointIsNotInTheHistory(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, out, server := startProxyWithClock(t, app.URL, "", time.Now, nil)
wantStatus(t, get(t, addr, proxy.HealthPath), http.StatusOK)
out.requestLine(t)
if clients := server.Limiter.Snapshot(); len(clients) != 0 {
t.Errorf("the table holds %+v, want no client", clients)
}
}
func TestRequestForSmallwebwafIsRefusedOnlyWithoutTheToken(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, out, server := startProxyWithClock(t, app.URL, "", time.Now,
map[string]string{metricsToken: token})
// The metrics and the 404 are neither forwarded nor refused; the 401
// is refused.
scrape(t, addr)
wantStatus(t, get(t, addr, "/_smallwebwaf/nothing"), http.StatusNotFound)
wantStatus(t, get(t, addr, proxy.MetricsPath), http.StatusUnauthorized)
out.requestLines(t, 3)
history := historyOf(t, server, localhost)
if history.Requests != 3 || history.Forwarded != 0 || history.Refused != 1 {
t.Errorf("history counts %d requests, %d forwarded and %d refused, "+
"want 3, 0 and 1", history.Requests, history.Forwarded, history.Refused)
}
}
// historyOf returns the history of the client at addr.
func historyOf(t *testing.T, server *proxy.Server, addr string) ratelimit.History {
t.Helper()
client := netip.MustParsePrefix(addr + "/32")
for _, c := range server.Limiter.Snapshot() {
if c.Client == client {
return c.History
}
}
t.Fatalf("%s is not in the table", client)
return ratelimit.History{}
}
internal/proxy/limits_test.go
+16
View File
@@ -55,6 +55,7 @@ func TestRequestBodyLimit(t *testing.T) {
})
addr, out := startProxy(t, app.URL, map[string]string{
requestMaxBytes: sizeLimitSetting,
metricsToken: token,
})
var body io.Reader = bytes.NewReader(make([]byte, tc.size))
@@ -66,6 +67,13 @@ func TestRequestBodyLimit(t *testing.T) {
tc.want)
wantLine(t, out.requestLine(t), tc.want, tc.action)
hits := 0
if tc.action == requestlog.ActionTooLarge {
hits = 1
}
wantLimitHits(t, addr, requestMaxBytes, hits)
if tc.refusedBeforeApp && calls.Load() != 0 {
t.Errorf("the app was called %d times, want never", calls.Load())
}
@@ -106,6 +114,7 @@ func TestResponseBodyLimit(t *testing.T) {
})
addr, out := startProxy(t, app.URL, map[string]string{
responseMaxBytes: sizeLimitSetting,
metricsToken: token,
})
got := get(t, addr, "/download")
@@ -123,6 +132,13 @@ func TestResponseBodyLimit(t *testing.T) {
if line.UpstreamStatus != http.StatusOK {
t.Errorf("log line has upstream_status %d", line.UpstreamStatus)
}
hits := 0
if tc.action == requestlog.ActionTooLarge {
hits = 1
}
wantLimitHits(t, addr, responseMaxBytes, hits)
})
}
}
internal/proxy/metrics_test.go
+455
View File
@@ -0,0 +1,455 @@
package proxy_test
import (
"io"
"net/http"
"net/http/httptest"
"net/netip"
"strconv"
"strings"
"sync"
"sync/atomic"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/lookup"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
const (
metricsToken = "SWWAF_METRICS_TOKEN" //nolint:gosec // the setting's name
metricsTopN = "SWWAF_METRICS_TOP_N"
// token is the SWWAF_METRICS_TOKEN the tests set, and bearer how a
// request carries it.
token = "0123456789abcdef0123456789abcdef"
bearer = "Bearer " + token
)
func TestMetricsAreOffWhileTheTokenIsUnset(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
addr, out := startProxy(t, app.URL, nil)
// An empty token does not match the unset one either.
for i, authorization := range []string{bearer, "Bearer ", ""} {
req := newRequest(t, http.MethodGet, addr, proxy.MetricsPath, http.NoBody)
if authorization != "" {
req.Header.Set("Authorization", authorization)
}
wantStatus(t, do(t, req), http.StatusNotFound)
wantLine(t, out.requestLines(t, i+1)[i], http.StatusNotFound,
requestlog.ActionAdmin)
}
if calls.Load() != 0 {
t.Errorf("the app was called %d times, want never", calls.Load())
}
}
func TestMetricsNeedTheTokenAndOtherPathsAreNotFound(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
addr, out := startProxy(t, app.URL, map[string]string{metricsToken: token})
for i, tc := range []struct {
method, path, authorization string
status int
}{
{http.MethodGet, proxy.MetricsPath, "", http.StatusUnauthorized},
{
http.MethodGet, proxy.MetricsPath, "Bearer " + strings.ToUpper(token),
http.StatusUnauthorized,
},
{http.MethodGet, proxy.MetricsPath, "Basic " + token, http.StatusUnauthorized},
{http.MethodGet, proxy.MetricsPath, bearer, http.StatusOK},
{http.MethodGet, proxy.MetricsPath, "bearer " + token, http.StatusOK},
{http.MethodPost, proxy.MetricsPath, bearer, http.StatusNotFound},
{http.MethodGet, proxy.MetricsPath + "/", bearer, http.StatusNotFound},
{http.MethodGet, "/_smallwebwaf/bans", bearer, http.StatusNotFound},
{http.MethodPost, proxy.HealthPath, "", http.StatusNotFound},
} {
req := newRequest(t, tc.method, addr, tc.path, http.NoBody)
if tc.authorization != "" {
req.Header.Set("Authorization", tc.authorization)
}
got := do(t, req)
wantStatus(t, got, tc.status)
wantLine(t, out.requestLines(t, i+1)[i], tc.status, requestlog.ActionAdmin)
if tc.status == http.StatusUnauthorized &&
got.header.Get("WWW-Authenticate") != "Bearer" {
t.Errorf("%q was answered without WWW-Authenticate: Bearer",
tc.authorization)
}
if tc.status == http.StatusOK &&
!strings.Contains(string(got.body), "# TYPE smallwebwaf_requests_total counter") {
t.Errorf("the metrics are\n%s", got.body)
}
}
if calls.Load() != 0 {
t.Errorf("the app was called %d times, want never", calls.Load())
}
}
func TestMetricsAreAskedForThroughTheChecks(t *testing.T) {
t.Parallel()
s, _, _ := startWithClock(t, "", map[string]string{
metricsToken: token,
rateLimitPerMinute: "1",
})
// Asking for the metrics counts toward the client's limit of one
// request a minute, so its next request breaks it, and bans it. A
// banned client is refused the metrics too.
s.scrape(client)
s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
s.requestWithHeader(client, proxy.MetricsPath, "Authorization: "+bearer,
http.StatusForbidden, requestlog.ActionBanned)
}
func TestMetricsCountTheTraffic(t *testing.T) {
t.Parallel()
arrived, release := make(chan struct{}), make(chan struct{})
app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
_, _ = io.Copy(io.Discard, r.Body)
if r.URL.Path == "/held" {
close(arrived)
<-release
}
_, _ = io.WriteString(w, "hello")
})
releaseApp := sync.OnceFunc(func() { close(release) })
t.Cleanup(releaseApp)
addr, out := startProxy(t, app.URL, map[string]string{metricsToken: token})
got := do(t, newRequest(t, http.MethodPost, addr, "/", strings.NewReader("abc")))
wantStatus(t, got, http.StatusOK)
wantStatus(t, get(t, addr, "/_smallwebwaf/nothing"), http.StatusNotFound)
out.requestLines(t, 2)
forward := `{action="forward",status_class="2xx"}`
notFound := `{action="admin",status_class="4xx"}`
// The request for the metrics is itself under way.
metrics := scrape(t, addr)
wantMetric(t, metrics, "smallwebwaf_requests_total"+forward, 1)
wantMetric(t, metrics, "smallwebwaf_requests_total"+notFound, 1)
wantMetric(t, metrics, "smallwebwaf_request_bytes_total"+forward, 3)
wantMetric(t, metrics, "smallwebwaf_response_bytes_total"+forward, 5)
wantMetric(t, metrics, "smallwebwaf_response_bytes_total"+notFound,
float64(len("Not Found\n")))
wantMetric(t, metrics, "smallwebwaf_request_duration_seconds_count", 2)
wantMetric(t, metrics, "smallwebwaf_upstream_duration_seconds_count", 1)
wantMetric(t, metrics, "smallwebwaf_requests_in_flight", 1)
metric(t, metrics, "go_goroutines")
metric(t, metrics, "process_start_time_seconds")
// A request the app holds is under way until it ends.
httpClient := newClient(t)
held := newRequest(t, http.MethodGet, addr, "/held", http.NoBody)
ended := make(chan error, 1)
go func() {
res, err := httpClient.Do(held)
if err == nil {
err = readAnswer(res).err
}
ended <- err
}()
<-arrived
wantMetric(t, scrape(t, addr), "smallwebwaf_requests_in_flight", 2)
releaseApp()
err := <-ended
if err != nil {
t.Fatalf("held request: %v", err)
}
out.requestLines(t, 5)
wantMetric(t, scrape(t, addr), "smallwebwaf_requests_in_flight", 1)
}
func TestMetricsCountLimitsAndBans(t *testing.T) {
t.Parallel()
const (
scraper = "192.0.2.200" // in SWWAF_RATE_LIMIT_EXEMPT_NETS
denied = "192.0.2.50" // in SWWAF_DENY_NETS
)
s, clk, _ := startWithClock(t, "", map[string]string{
metricsToken: token,
rateLimitPerMinute: "1",
rateLimitExemptNets: scraper,
denyNets: denied,
banResponse: "close",
limitBanDuration: "1h",
maxBanDuration: "2h",
})
// SWWAF_BAN_RESPONSE=close sends no status at all.
s.get(denied, 0, requestlog.ActionDenied)
// A first broken limit bans for an hour.
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, 0, requestlog.ActionRateLimited)
metrics := s.scrape(scraper)
wantMetric(t, metrics,
`smallwebwaf_requests_total{action="denied",status_class="none"}`, 1)
wantMetric(t, metrics, `smallwebwaf_rate_limit_hits_total{window="minute"}`, 1)
wantMetric(t, metrics, `smallwebwaf_offences_total{kind="limit"}`, 1)
wantMetric(t, metrics, `smallwebwaf_bans_made_total{cause="limit"}`, 1)
wantMetric(t, metrics, "smallwebwaf_active_bans", 1)
wantMetric(t, metrics, "smallwebwaf_permanent_bans", 0)
clk.advance(time.Hour)
wantMetric(t, s.scrape(scraper), "smallwebwaf_active_bans", 0)
// A limit broken again right after would ban for three hours, longer
// than SWWAF_MAX_BAN_DURATION, so the ban is permanent.
s.get(client, http.StatusOK, requestlog.ActionForward)
s.get(client, 0, requestlog.ActionRateLimited)
metrics = s.scrape(scraper)
wantMetric(t, metrics, `smallwebwaf_rate_limit_hits_total{window="minute"}`, 2)
wantMetric(t, metrics, `smallwebwaf_offences_total{kind="limit"}`, 2)
wantMetric(t, metrics, `smallwebwaf_bans_made_total{cause="limit"}`, 2)
wantMetric(t, metrics, "smallwebwaf_active_bans", 1)
wantMetric(t, metrics, "smallwebwaf_permanent_bans", 1)
// denied, client, and the scraper as of its earlier requests.
wantMetric(t, metrics, "smallwebwaf_tracked_clients", 3)
}
func TestMetricsByCountryKeepTheBusiestAndCountTheRestAsOther(t *testing.T) {
t.Parallel()
const fromFR = "198.51.100.20"
app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
_, _ = io.Copy(io.Discard, r.Body)
_, _ = io.WriteString(w, "hello")
})
env := map[string]string{
trustedProxies: trustLocalhost,
metricsToken: token,
metricsTopN: "2",
deniedCountries: "kp",
}
addr, out, server := startProxyWithClock(t, app.URL, "", time.Now, env)
// The answers are kept before the requests, so that none waits for
// GeoJS.
server.GeoJS.Load([]lookup.Answer{
keptAnswer(fromKP, "KP"), keptAnswer(fromDE, "DE"), keptAnswer(fromFR, "FR"),
})
lines := 0
send := func(from string, times, status int) {
t.Helper()
for range times {
req := newRequest(t, http.MethodPost, addr, "/", strings.NewReader("abc"))
req.Header.Set(forwardedFor, from)
wantStatus(t, do(t, req), status)
// Each is counted before the next is sent, so that the
// countries are ranked in the order sent.
lines++
out.requestLines(t, lines)
}
}
// With two countries of their own, the third is counted as other.
send(fromKP, 3, http.StatusForbidden)
send(fromDE, 2, http.StatusOK)
send(fromFR, 1, http.StatusOK)
metrics := scrape(t, addr)
lines++
wantMetric(t, metrics, `smallwebwaf_country_requests_total{country="KP"}`, 3)
wantMetric(t, metrics, `smallwebwaf_country_requests_total{country="DE"}`, 2)
wantMetric(t, metrics, `smallwebwaf_country_requests_total{country="other"}`, 1)
wantMetric(t, metrics, `smallwebwaf_country_list_refusals_total{country="KP"}`, 3)
wantMetric(t, metrics, `smallwebwaf_country_request_bytes_total{country="KP"}`, 0)
wantMetric(t, metrics, `smallwebwaf_country_request_bytes_total{country="DE"}`, 6)
wantMetric(t, metrics, `smallwebwaf_country_response_bytes_total{country="KP"}`,
float64(3*len("Forbidden\n")))
wantMetric(t, metrics, `smallwebwaf_country_response_bytes_total{country="other"}`,
float64(len("hello")))
wantNoSeries(t, metrics, `smallwebwaf_country_requests_total{country="FR"}`)
// Once FR is busier than DE, it takes DE's place: its series counts
// from then on, and DE's is gone.
send(fromFR, 3, http.StatusOK)
metrics = scrape(t, addr)
wantMetric(t, metrics, `smallwebwaf_country_requests_total{country="KP"}`, 3)
wantMetric(t, metrics, `smallwebwaf_country_requests_total{country="FR"}`, 2)
wantMetric(t, metrics, `smallwebwaf_country_requests_total{country="other"}`, 2)
wantNoSeries(t, metrics, `smallwebwaf_country_requests_total{country="DE"}`)
wantNoSeries(t, metrics, `smallwebwaf_country_request_bytes_total{country="DE"}`)
}
func TestMetricsCountGeoJSRequestsAndFailures(t *testing.T) {
t.Parallel()
geojs := httptest.NewServer(http.HandlerFunc(
func(w http.ResponseWriter, _ *http.Request) {
w.WriteHeader(http.StatusServiceUnavailable)
}))
t.Cleanup(geojs.Close)
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, _ := startProxyWithGeoJS(t, app.URL, geojs.URL, map[string]string{
trustedProxies: trustLocalhost,
metricsToken: token,
deniedCountries: "kp",
})
// GeoJS fails, so the client counts as coming from an unknown country,
// which SWWAF_DENIED_COUNTRIES does not refuse.
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
req.Header.Set(forwardedFor, fromDE)
wantStatus(t, do(t, req), http.StatusOK)
// The client stops waiting for GeoJS after a second, so GeoJS's
// failure can come after its request has ended.
deadline := time.Now().Add(waitLimit)
metrics := scrape(t, addr)
for metric(t, metrics, "smallwebwaf_geojs_failures_total") == 0 &&
time.Now().Before(deadline) {
time.Sleep(pollInterval)
metrics = scrape(t, addr)
}
wantMetric(t, metrics, "smallwebwaf_geojs_requests_total", 1)
wantMetric(t, metrics, "smallwebwaf_geojs_failures_total", 1)
wantMetric(t, metrics, "smallwebwaf_geojs_unanswered_total", 1)
}
// keptAnswer returns GeoJS's answer that the client at addr is in
// country, given now.
func keptAnswer(addr, country string) lookup.Answer {
now := time.Now()
return lookup.Answer{
Client: netip.MustParsePrefix(addr + "/32"), Country: country,
Answered: now, Used: now,
}
}
// scrape asks smallwebwaf at addr for the metrics, with the token, and
// returns them.
func scrape(t *testing.T, addr string) string {
t.Helper()
req := newRequest(t, http.MethodGet, addr, proxy.MetricsPath, http.NoBody)
req.Header.Set("Authorization", bearer)
got := do(t, req)
if got.status != http.StatusOK {
t.Fatalf("the metrics were answered %d", got.status)
}
return string(got.body)
}
// scrape asks for the metrics, with the token, from the client at from,
// and returns them.
func (s *sender) scrape(from string) string {
s.t.Helper()
_, metrics := s.requestWithHeader(from, proxy.MetricsPath, "Authorization: "+bearer,
http.StatusOK, requestlog.ActionAdmin)
return metrics
}
// metric returns the value of series in metrics, which are in the
// Prometheus text format. series is a name and its labels in the order of
// their names, such as smallwebwaf_offences_total{kind="limit"}. It fails
// the test if there is no such series.
func metric(t *testing.T, metrics, series string) float64 {
t.Helper()
for line := range strings.Lines(metrics) {
value, found := strings.CutPrefix(strings.TrimSuffix(line, "\n"), series+" ")
if !found {
continue
}
number, err := strconv.ParseFloat(value, 64)
if err != nil {
t.Fatalf("%s has the value %q", series, value)
}
return number
}
t.Fatalf("no series %s in the metrics:\n%s", series, metrics)
return 0
}
// wantMetric checks the value of series in metrics, as metric reads it.
func wantMetric(t *testing.T, metrics, series string, want float64) {
t.Helper()
got := metric(t, metrics, series)
if got != want {
t.Errorf("%s is %v, want %v", series, got, want)
}
}
// wantNoSeries checks that metrics have no series series.
func wantNoSeries(t *testing.T, metrics, series string) {
t.Helper()
if strings.Contains(metrics, "\n"+series+" ") {
t.Errorf("there is a series %s", series)
}
}
// wantLimitHits checks that the metrics of smallwebwaf at addr count hits
// requests that passed the size or time limit of the setting limit, with
// no series for it when hits is 0.
func wantLimitHits(t *testing.T, addr, limit string, hits int) {
t.Helper()
series := `smallwebwaf_size_and_time_limit_hits_total{limit="` + limit + `"}`
metrics := scrape(t, addr)
if hits == 0 {
wantNoSeries(t, metrics, series)
return
}
wantMetric(t, metrics, series, float64(hits))
}
internal/proxy/observe_test.go
+202
View File
@@ -0,0 +1,202 @@
package proxy_test
import (
"bytes"
"io"
"net/http"
"net/netip"
"sync/atomic"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/bans"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// observe is the value of SWWAF_MODE for observe mode.
const observe = "observe"
func TestObserveModeForwardsWhatEnforceModeRefuses(t *testing.T) {
t.Parallel()
const (
denied = "192.0.2.50" // in SWWAF_DENY_NETS
banned = otherClient // under a ban read from bans.json
)
for _, tc := range []struct {
setting string // "" leaves SWWAF_MODE at its default
observe bool
}{
{"", false},
{"enforce", false},
{observe, true},
} {
t.Run(mode+"="+tc.setting, func(t *testing.T) {
t.Parallel()
geojsURL, _ := startGeoJS(t)
env := map[string]string{
rateLimitPerMinute: "1",
denyNets: denied,
deniedCountries: "kp",
}
if tc.setting != "" {
env[mode] = tc.setting
}
s, clk, server := startWithClock(t, geojsURL, env)
server.Ledger.Load([]bans.Ban{{
Netblock: netip.MustParsePrefix(banned + "/32"),
Start: clk.Now(),
Expires: clk.Now().Add(time.Hour),
}})
// fromDE's first request is within the limit of one a minute,
// and its second breaks it.
s.get(fromDE, http.StatusOK, requestlog.ActionForward)
for _, sent := range []struct{ from, refusal string }{
{denied, requestlog.ActionDenied},
{banned, requestlog.ActionBanned},
{fromKP, requestlog.ActionCountryDenied},
{fromDE, requestlog.ActionRateLimited},
} {
if !tc.observe {
line := s.get(sent.from, http.StatusForbidden, sent.refusal)
wantWouldAction(t, line, "")
continue
}
// Passed to the app, which answered it.
line := s.get(sent.from, http.StatusOK, requestlog.ActionForward)
wantWouldAction(t, line, sent.refusal)
if line.UpstreamStatus != http.StatusOK {
t.Errorf("log line has upstream_status %d, want 200",
line.UpstreamStatus)
}
}
})
}
}
func TestObserveModeMakesNoBanAndKeepsTheBansItHas(t *testing.T) {
t.Parallel()
s, clk, server := startWithClock(t, "", map[string]string{
mode: observe,
rateLimitPerMinute: "1",
})
kept := bans.Ban{
Netblock: netip.MustParsePrefix(otherClient + "/32"),
Start: clk.Now(),
Expires: clk.Now().Add(time.Hour),
}
server.Ledger.Load([]bans.Ban{kept})
// No ban sets client's counters back to zero, so each request after
// the first breaks the limit of one a minute.
s.get(client, http.StatusOK, requestlog.ActionForward)
for range 2 {
line := s.get(client, http.StatusOK, requestlog.ActionForward)
wantWouldAction(t, line, requestlog.ActionRateLimited)
if line.LimitHit != minute || line.Offence != requestlog.OffenceLimit ||
line.BanExpires != "" {
t.Errorf("log line has limit_hit %q, offence %q and ban_expires %q, "+
"want minute, limit and none", line.LimitHit, line.Offence,
line.BanExpires)
}
}
// The ban read from bans.json refuses nothing, and so counts no
// refusal in its notes, but is kept.
line := s.get(otherClient, http.StatusOK, requestlog.ActionForward)
wantWouldAction(t, line, requestlog.ActionBanned)
if line.BanExpires != requestlog.FormatTime(kept.Expires) {
t.Errorf("log line has ban_expires %q, want %s", line.BanExpires,
requestlog.FormatTime(kept.Expires))
}
got := server.Ledger.Snapshot()
if len(got) != 1 || got[0] != kept {
t.Errorf("bans\n%+v\nwant only\n%+v", got, kept)
}
}
func TestObserveModeKeepsTheSizeLimitsAndTheToken(t *testing.T) {
t.Parallel()
const denied = "192.0.2.50" // in SWWAF_DENY_NETS
var calls atomic.Int32
app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
calls.Add(1)
answerWithSize(w, 2*sizeLimit, true)
})
addr, out := startProxy(t, app.URL, map[string]string{
mode: observe,
trustedProxies: trustLocalhost,
denyNets: denied,
requestMaxBytes: sizeLimitSetting,
responseMaxBytes: sizeLimitSetting,
metricsToken: token,
})
// SWWAF_DENY_NETS would refuse each request; instead a size limit or
// the missing token does.
for i, tc := range []struct {
method, path string
body io.Reader
status int
action string
}{
{
http.MethodPost, "/upload", bytes.NewReader(make([]byte, 2*sizeLimit)),
http.StatusRequestEntityTooLarge, requestlog.ActionTooLarge,
},
{
http.MethodGet, "/download", http.NoBody,
http.StatusBadGateway, requestlog.ActionTooLarge,
},
{
http.MethodGet, proxy.MetricsPath, http.NoBody,
http.StatusUnauthorized, requestlog.ActionAdmin,
},
} {
req := newRequest(t, tc.method, addr, tc.path, tc.body)
req.Header.Set(forwardedFor, denied)
wantStatus(t, do(t, req), tc.status)
line := out.requestLines(t, i+1)[i]
wantLine(t, line, tc.status, tc.action)
wantWouldAction(t, line, requestlog.ActionDenied)
}
// The upload was refused before it reached the app.
if calls.Load() != 1 {
t.Errorf("the app was called %d times, want once", calls.Load())
}
}
// wantWouldAction checks the request log line's would_action, and that a
// line that should have none has no such field.
func wantWouldAction(t *testing.T, line logLine, want string) {
t.Helper()
got, present := line.fields["would_action"]
switch {
case want == "" && present:
t.Errorf("log line has would_action %v, want none", got)
case want != "" && got != want:
t.Errorf("log line has would_action %v, want %s", got, want)
}
}
internal/proxy/passthrough_test.go
+74 -53
View File
@@ -5,8 +5,9 @@ import (
"bytes"
"errors"
"io"
"net"
"net/http"
"os"
"reflect"
"slices"
"strings"
"sync/atomic"
@@ -15,6 +16,7 @@ import (
"sneak.berlin/go/smallwebwaf/internal/config"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
@@ -116,27 +118,34 @@ func wantAnswer(t *testing.T, got answer, body []byte) {
}
}
// wantRequestFields checks the log line's fields about the request.
// wantRequestFields checks the log line's fields about the request. Its
// time, its id and its timings are checked only for being there.
func wantRequestFields(t *testing.T, line logLine, host string, sent, received int) {
t.Helper()
want := requestlog.Line{
Type: "request", Time: line.Time, ClientIP: localhost, PeerIP: localhost,
Method: http.MethodPatch, Host: host, Path: rawPath, Query: rawQuery,
Protocol: "HTTP/1.1", Status: http.StatusTeapot,
UpstreamStatus: http.StatusTeapot, RequestBytes: int64(sent),
hostname, _ := os.Hostname()
want := withTimings(line, requestlog.Line{
Type: requestType, Time: line.Time, Instance: hostname,
ClientIP: localhost, Method: http.MethodPatch, Scheme: plain, Host: host,
Path: rawPath, Query: rawQuery, Protocol: protocol,
Status: http.StatusTeapot, RequestBytes: int64(sent),
ResponseBytes: int64(received), UserAgent: "test-agent",
Action: requestlog.ActionForward, DurationTotal: line.DurationTotal,
DurationUpstreamTotal: line.DurationUpstreamTotal,
}
if line.Line != want {
RequestID: line.RequestID, PeerIP: localhost, ClientGroup: localhost + "/32",
ContentLength: int64(sent), ResponseContentType: "text/plain; charset=utf-8",
UpstreamStatus: http.StatusTeapot, Action: requestlog.ActionForward,
Counts: ratelimit.Counts{Minute: 1, Hour: 1, Day: 1},
})
if !reflect.DeepEqual(line.Line, want) {
t.Errorf("log line\n%+v\nwant\n%+v", line.Line, want)
}
_, err := time.Parse(time.RFC3339, line.Time)
if err != nil || line.DurationTotal <= 0 || line.DurationUpstreamTotal <= 0 {
t.Errorf("log line has time %q and durations %v and %v",
line.Time, line.DurationTotal, line.DurationUpstreamTotal)
if err != nil || line.RequestID == "" || line.DurationTotal <= 0 ||
line.DurationUpstreamTotal == nil || *line.DurationUpstreamTotal <= 0 {
t.Errorf("log line has time %q, request_id %q and durations %v and %v",
line.Time, line.RequestID, line.DurationTotal,
line.fields["duration_upstream_total"])
}
}
@@ -241,14 +250,17 @@ func TestUpgradedConnectionOutlastsTheTimeouts(t *testing.T) {
t.Fatalf("read the answer to the upgrade: %v", err)
}
answered := time.Now()
_ = res.Body.Close()
if res.StatusCode != http.StatusSwitchingProtocols {
t.Fatalf("status %d, want %d", res.StatusCode, http.StatusSwitchingProtocols)
}
// Wait past every timeout, then use the connection.
time.Sleep(3 * shortTimeout)
// Every timeout started before the upgrade was answered, the response
// timeouts last, at the end of the request: wait until just past
// shortTimeout after the answer was read, then use the connection.
time.Sleep(time.Until(answered.Add(shortTimeout + 100*time.Millisecond)))
send(t, conn, "still here\n")
echoed, err := reader.ReadString('\n')
@@ -295,7 +307,7 @@ func echoAfterUpgrade(w http.ResponseWriter, r *http.Request) {
}
}
func TestServerHasTheFixedLimits(t *testing.T) {
func TestServerHasTheDefaultLimits(t *testing.T) {
t.Parallel()
cfg, err := config.FromEnvironment(func(string) (string, bool) { return "", false })
@@ -317,56 +329,65 @@ func TestServerHasTheFixedLimits(t *testing.T) {
}
}
func TestRefusesHeadersOver32KiB(t *testing.T) {
func TestRefusesHeadersOverTheLimit(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
addr, _ := startProxy(t, app.URL, nil)
// size counts every byte of the request: the request line, the
// headers and the blank line that ends them.
const (
start = "GET / HTTP/1.1\r\nHost: app\r\nX-Large: "
end = "\r\n\r\n"
)
for _, tc := range []struct {
size int
want int
name string
env map[string]string
limit int
}{
{size: 32 << 10, want: http.StatusOK},
{size: 32<<10 + 1, want: http.StatusRequestHeaderFieldsTooLarge},
{"by default", nil, 32 << 10},
{"as set", map[string]string{clientHeaderMaxBytes: "8K"}, 8 << 10},
} {
conn := dial(t, addr)
send(t, conn, start+strings.Repeat("a", tc.size-len(start)-len(end))+end)
wantStatus(t, readResponse(t, conn), tc.want)
}
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
if calls.Load() != 1 {
t.Errorf("the app was called %d times, want once", calls.Load())
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
addr, _ := startProxy(t, app.URL, tc.env)
// size counts every byte of the request: the request line,
// the headers and the blank line that ends them.
const (
start = "GET / HTTP/1.1\r\nHost: app\r\nX-Large: "
end = "\r\n\r\n"
)
for _, sent := range []struct{ size, want int }{
{tc.limit, http.StatusOK},
{tc.limit + 1, http.StatusRequestHeaderFieldsTooLarge},
} {
conn := dial(t, addr)
send(t, conn,
start+strings.Repeat("a", sent.size-len(start)-len(end))+end)
wantStatus(t, readResponse(t, conn), sent.want)
}
if calls.Load() != 1 {
t.Errorf("the app was called %d times, want once", calls.Load())
}
})
}
}
func TestAnswers502WhenTheAppCannotBeReached(t *testing.T) {
t.Parallel()
listener, err := (&net.ListenConfig{}).Listen(t.Context(), "tcp", localhost+":0")
if err != nil {
t.Fatalf("listen: %v", err)
}
closedAddr := listener.Addr().String()
_ = listener.Close()
addr, out := startProxy(t, "http://"+closedAddr, nil)
// No test can listen on port 1: listening on port 0 gets one from 32768 up.
addr, out := startProxy(t, "http://"+localhost+":1", nil)
wantStatus(t, get(t, addr, "/"), http.StatusBadGateway)
wantLine(t, out.requestLine(t), http.StatusBadGateway,
requestlog.ActionUpstreamError)
line := out.requestLine(t)
wantLine(t, line, http.StatusBadGateway, requestlog.ActionUpstreamError)
// There never was a connection to the app, nor an answer from it.
wantTimings(t, line, "duration_total", "duration_checks",
"duration_upstream_total")
logged := slices.ContainsFunc(out.lines(t), func(line map[string]any) bool {
return line["type"] == "process" && line["msg"] == "request to the app failed"
internal/proxy/proxy.go
+115 -35
View File
@@ -8,23 +8,15 @@ import (
"log"
"log/slog"
"net/http"
"strings"
"time"
"sneak.berlin/go/smallwebwaf/internal/bans"
"sneak.berlin/go/smallwebwaf/internal/config"
"sneak.berlin/go/smallwebwaf/internal/lookup"
"sneak.berlin/go/smallwebwaf/internal/metrics"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
)
// The request line and headers a client may send, and how long a
// kept-open client connection may wait for its next request, are fixed
// rather than settings. The limit on the request line and headers is
// 32 KiB, but Go's server reads 4 KiB past its MaxHeaderBytes before it
// refuses, so MaxHeaderBytes is set 4 KiB lower. The idle time is longer
// than the 90 seconds after which traefik closes a connection it is not
// using, so traefik never sends a request on a connection smallwebwaf is
// closing.
const (
requestHeaderMaxBytes = 32<<10 - 4<<10
clientIdleTimeout = 120 * time.Second
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// How smallwebwaf keeps connections to the app open between requests.
@@ -33,6 +25,18 @@ const (
appIdleConnTimeout = 90 * time.Second
)
// adminPrefix starts the path of every request for smallwebwaf itself,
// which never reaches the app.
const adminPrefix = "/_smallwebwaf/"
// HealthPath is smallwebwaf's health endpoint, which the container's
// health check asks.
const HealthPath = "/_smallwebwaf/healthz"
// MetricsPath is where the metrics are, for a request that carries
// SWWAF_METRICS_TOKEN.
const MetricsPath = "/_smallwebwaf/metrics"
// Params are what New needs.
type Params struct {
Config *config.Config
@@ -40,34 +44,80 @@ type Params struct {
RequestLog io.Writer
// ProcessLog receives the process's own messages.
ProcessLog *slog.Logger
// GeoJSURL is where clients' countries are looked up, normally
// lookup.URL. GeoJS is asked only while a country list is set.
GeoJSURL string
// Now tells the time by which requests are counted for the rate
// limits, bans are made and run out, and GeoJS's answers are kept,
// normally time.Now in UTC, the time the state files give.
Now func() time.Time
}
// Server is the server smallwebwaf runs, with the parts of the proxy
// whose state the state files keep, and the metrics.
type Server struct {
*http.Server
Ledger *bans.Ledger
Limiter *ratelimit.Limiter
GeoJS *lookup.GeoJS
Metrics *metrics.Metrics
}
// New returns the server smallwebwaf runs: each request it reads passes
// through the proxy. Go's server itself refuses headers over 32 KiB, with
// 431, closes a connection idle for 120 seconds, and applies
// through the proxy. Go's server itself refuses a request line and
// headers over SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES, with 431, closes a
// connection idle for SWWAF_CLIENT_IDLE_TIMEOUT, and applies
// SWWAF_CLIENT_REQUEST_TIMEOUT while the headers arrive; the proxy
// applies the timeouts and size limits from then on.
func New(params Params) *http.Server {
func New(params Params) *Server {
errorLog := slog.NewLogLogger(params.ProcessLog.Handler(), slog.LevelWarn)
m := metrics.New(params.Config.MetricsTopN)
h := &handler{
config: params.Config,
requestLog: params.RequestLog,
processLog: params.ProcessLog,
errorLog: errorLog,
transport: newTransport(),
now: params.Now,
metrics: m,
limiter: ratelimit.New(ratelimit.Limits{
PerMinute: params.Config.RateLimitPerMinute,
PerHour: params.Config.RateLimitPerHour,
PerDay: params.Config.RateLimitPerDay,
}),
ledger: bans.New(bans.Rules{
LimitBanDuration: params.Config.LimitBanDuration,
LimitBanRepeatWindow: params.Config.LimitBanRepeatWindow,
MaxBanDuration: params.Config.MaxBanDuration,
MaxBans: params.Config.MaxBans,
}),
geojs: lookup.New(lookup.Params{
URL: params.GeoJSURL,
Now: params.Now,
ProcessLog: params.ProcessLog,
Metrics: m,
}),
}
m.AddBansAndClients(h.ledger, h.limiter, params.Now)
return &http.Server{
Addr: params.Config.ListenAddr,
Handler: &handler{
config: params.Config,
requestLog: params.RequestLog,
processLog: params.ProcessLog,
errorLog: errorLog,
transport: newTransport(),
limiter: ratelimit.New(ratelimit.Limits{
PerMinute: params.Config.RateLimitPerMinute,
PerHour: params.Config.RateLimitPerHour,
PerDay: params.Config.RateLimitPerDay,
}),
return &Server{
Server: &http.Server{
Addr: params.Config.ListenAddr,
Handler: h,
ReadHeaderTimeout: params.Config.ClientRequestTimeout,
// Off is an IdleTimeout of 0, which Go's server replaces with
// ReadTimeout: no limit, as long as ReadTimeout stays unset.
IdleTimeout: params.Config.ClientIdleTimeout,
// Go's server reads 4 KiB past MaxHeaderBytes before it
// refuses, so the limit a client meets is the setting.
MaxHeaderBytes: int(params.Config.ClientRequestHeaderMaxBytes - 4<<10),
ErrorLog: errorLog,
},
ReadHeaderTimeout: params.Config.ClientRequestTimeout,
IdleTimeout: clientIdleTimeout,
MaxHeaderBytes: requestHeaderMaxBytes,
ErrorLog: errorLog,
Ledger: h.ledger,
Limiter: h.limiter,
GeoJS: h.geojs,
Metrics: m,
}
}
@@ -79,7 +129,11 @@ type handler struct {
processLog *slog.Logger
errorLog *log.Logger
transport http.RoundTripper
now func() time.Time
metrics *metrics.Metrics
limiter *ratelimit.Limiter
ledger *bans.Ledger
geojs *lookup.GeoJS
}
// newTransport returns what carries requests to the app. It never goes
@@ -96,17 +150,43 @@ func newTransport() *http.Transport {
// ServeHTTP handles one request: it works out the client, runs the
// checks, passes the request to the app and the answer back within the
// limits, and writes the request's log line.
// limits, or answers it itself if it is for smallwebwaf, and writes the
// request's log line.
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
rq := h.newRequest(w, r)
defer rq.finish()
refused := rq.check()
// The health endpoint is answered at once, before any check, so that
// a health checker is never refused. It does not ask the app.
if r.Method == http.MethodGet && r.URL.Path == HealthPath {
rq.line.Action = requestlog.ActionAdmin
// Set here rather than left to Go's server, which would set it only
// after the log line has taken the response's headers.
rq.out.Header().Set("Content-Type", "text/plain; charset=utf-8")
_, _ = io.WriteString(rq.out, "ok\n")
return
}
// Once the request has ended, before its log line is written.
defer rq.addToHistory()
refused := rq.check(r.Context())
rq.checked = time.Now()
if refused != nil {
rq.answer(*refused)
return
}
// A request for smallwebwaf itself is answered where another would be
// passed to the app, so that it goes through every check first.
if strings.HasPrefix(r.URL.Path, adminPrefix) {
rq.answerAdmin()
return
}
rq.forward(r.Context())
}
internal/proxy/proxy_test.go
+68 -6
View File
@@ -21,11 +21,13 @@ import (
const (
// shortTimeout is what a test sets a timeout to, to see it run out.
shortTimeout = 300 * time.Millisecond
// shortTimeoutSetting is shortTimeout as a setting's value.
shortTimeoutSetting = "300ms"
// It starts before the test has set up its case, such as an upgrade
// or the app's buffers filling, so it is as long as the hold-up of the
// test process that wantTimedOut allows: a shorter one can run out
// first on a busy host.
shortTimeout = waitLimit / 2
// longTimeoutSetting is a timeout that does not run out in a test.
longTimeoutSetting = "10s"
longTimeoutSetting = "1m"
// waitLimit bounds how long a test waits for what should happen.
waitLimit = 10 * time.Second
// pollInterval is how often a test looks for a log line.
@@ -33,18 +35,45 @@ const (
// localhost is where every test server listens, and so the address
// smallwebwaf sees each test's requests come from.
localhost = "127.0.0.1"
// requestType is the type that marks a request log line.
requestType = "request"
// protocol is the protocol of every test's requests.
protocol = "HTTP/1.1"
)
// shortTimeoutSetting is shortTimeout as a setting's value.
//
//nolint:gochecknoglobals // a constant cannot call String
var shortTimeoutSetting = shortTimeout.String()
// The settings the tests set.
const (
clientRequestTimeout = "SWWAF_CLIENT_REQUEST_TIMEOUT"
clientHeaderMaxBytes = "SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES"
clientIdleTimeout = "SWWAF_CLIENT_IDLE_TIMEOUT"
clientResponseTimeout = "SWWAF_CLIENT_RESPONSE_TIMEOUT"
upstreamRequestTimeout = "SWWAF_UPSTREAM_REQUEST_TIMEOUT"
upstreamResponseTimeout = "SWWAF_UPSTREAM_RESPONSE_TIMEOUT"
mode = "SWWAF_MODE"
requestMaxBytes = "SWWAF_REQUEST_MAX_BYTES"
responseMaxBytes = "SWWAF_RESPONSE_MAX_BYTES"
trustedProxies = "SWWAF_TRUSTED_PROXIES"
allowNets = "SWWAF_ALLOW_NETS"
rateLimitExemptNets = "SWWAF_RATE_LIMIT_EXEMPT_NETS"
denyNets = "SWWAF_DENY_NETS"
rateLimitPerMinute = "SWWAF_RATE_LIMIT_PER_MINUTE"
rateLimitPerDay = "SWWAF_RATE_LIMIT_PER_DAY"
rateLimitExemptPaths = "SWWAF_RATE_LIMIT_EXEMPT_PATHS"
deniedCountries = "SWWAF_DENIED_COUNTRIES"
allowedCountries = "SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES"
banResponse = "SWWAF_BAN_RESPONSE"
limitBanDuration = "SWWAF_LIMIT_BAN_DURATION"
limitBanRepeatWindow = "SWWAF_LIMIT_BAN_REPEAT_WINDOW"
maxBanDuration = "SWWAF_MAX_BAN_DURATION"
maxBans = "SWWAF_MAX_BANS"
banScopeV4Prefix = "SWWAF_BAN_SCOPE_V4_PREFIX"
instanceName = "SWWAF_INSTANCE_NAME"
logRequestHeaders = "SWWAF_LOG_REQUEST_HEADERS"
)
// output collects what smallwebwaf writes on stdout.
@@ -61,6 +90,14 @@ func (o *output) Write(p []byte) (int, error) {
return o.buf.Write(p)
}
// text returns everything written so far.
func (o *output) text() string {
o.mu.Lock()
defer o.mu.Unlock()
return o.buf.String()
}
// lines returns every line written so far, decoded.
func (o *output) lines(t *testing.T) []map[string]any {
t.Helper()
@@ -100,7 +137,7 @@ func (o *output) requestLines(t *testing.T, count int) []logLine {
var found []logLine
for _, fields := range o.lines(t) {
if fields["type"] == "request" {
if fields["type"] == requestType {
found = append(found, decodeLine(t, fields))
}
}
@@ -159,6 +196,29 @@ func startApp(t *testing.T, app http.HandlerFunc) *httptest.Server {
func startProxy(t *testing.T, appURL string, env map[string]string) (string, *output) {
t.Helper()
return startProxyWithGeoJS(t, appURL, "", env)
}
// startProxyWithGeoJS is startProxy with clients' countries looked up at
// geojsURL.
func startProxyWithGeoJS(
t *testing.T, appURL, geojsURL string, env map[string]string,
) (string, *output) {
t.Helper()
addr, out, _ := startProxyWithClock(t, appURL, geojsURL, time.Now, env)
return addr, out
}
// startProxyWithClock is startProxyWithGeoJS with requests counted and
// bans made by the time now tells, and returns the server as well.
func startProxyWithClock(
t *testing.T, appURL, geojsURL string, now func() time.Time,
env map[string]string,
) (string, *output, *proxy.Server) {
t.Helper()
settings := map[string]string{"SWWAF_UPSTREAM_URL": appURL}
maps.Copy(settings, env)
@@ -176,6 +236,8 @@ func startProxy(t *testing.T, appURL string, env map[string]string) (string, *ou
Config: cfg,
RequestLog: out,
ProcessLog: requestlog.NewProcessLogger(out),
GeoJSURL: geojsURL,
Now: now,
})
listener, err := (&net.ListenConfig{}).Listen(t.Context(), "tcp", localhost+":0")
@@ -191,7 +253,7 @@ func startProxy(t *testing.T, appURL string, env map[string]string) (string, *ou
_ = server.Close()
})
return listener.Addr().String(), out
return listener.Addr().String(), out, server
}
// newClient returns an HTTP client that sends requests as they are made,
internal/proxy/ratelimits_test.go
+100 -8
View File
@@ -5,10 +5,16 @@ import (
"sync/atomic"
"testing"
"sneak.berlin/go/smallwebwaf/internal/lookup"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
func TestRateLimitRefusesWith429BeforeTheApp(t *testing.T) {
// minute is the window of SWWAF_RATE_LIMIT_PER_MINUTE, as a log line's
// limit_hit names it.
const minute = "minute"
func TestRateLimitRefusesBeforeTheApp(t *testing.T) {
t.Parallel()
var calls atomic.Int32
@@ -24,19 +30,19 @@ func TestRateLimitRefusesWith429BeforeTheApp(t *testing.T) {
const otherClient = "203.0.113.10"
// With a limit of one request a minute, a client's second request is
// refused. A client is one IPv4 address, or one IPv6 /64; an IPv4
// address in IPv6 form is that IPv4 address.
// refused, with 403 by default. A client is one IPv4 address, or one
// IPv6 /64; an IPv4 address in IPv6 form is that IPv4 address.
requests := []struct {
client string // as X-Forwarded-For names it
logged string // as the log line's client_ip names it
want int
}{
{client, client, http.StatusOK},
{client, client, http.StatusTooManyRequests},
{client, client, http.StatusForbidden},
{otherClient, otherClient, http.StatusOK},
{"::ffff:" + otherClient, otherClient, http.StatusTooManyRequests},
{"::ffff:" + otherClient, otherClient, http.StatusForbidden},
{"2001:db8::1", "2001:db8::1", http.StatusOK},
{"2001:db8::8000:0:0:1", "2001:db8::8000:0:0:1", http.StatusTooManyRequests},
{"2001:db8::8000:0:0:1", "2001:db8::8000:0:0:1", http.StatusForbidden},
{"2001:db8:0:1::1", "2001:db8:0:1::1", http.StatusOK},
}
@@ -53,9 +59,9 @@ func TestRateLimitRefusesWith429BeforeTheApp(t *testing.T) {
if sent.want == http.StatusOK {
wantLine(t, line, http.StatusOK, requestlog.ActionForward)
} else {
wantLine(t, line, http.StatusTooManyRequests, requestlog.ActionRateLimited)
wantLine(t, line, http.StatusForbidden, requestlog.ActionRateLimited)
if line.LimitHit != "minute" {
if line.LimitHit != minute {
t.Errorf("log line has limit_hit %q, want minute", line.LimitHit)
}
}
@@ -65,3 +71,89 @@ func TestRateLimitRefusesWith429BeforeTheApp(t *testing.T) {
t.Errorf("the app was called %d times, want 4", calls.Load())
}
}
func TestRateLimitExemptPathsAreNeitherCountedNorRefused(t *testing.T) {
t.Parallel()
const denied = "192.0.2.50" // in SWWAF_DENY_NETS
s, _, server := startWithClock(t, "", map[string]string{
rateLimitPerMinute: "1",
rateLimitExemptPaths: "/assets/,/favicon.ico",
denyNets: denied,
deniedCountries: "kp",
})
// The answers are kept before the requests, so that none waits for
// GeoJS.
server.GeoJS.Load([]lookup.Answer{
keptAnswer(client, "DE"), keptAnswer(fromKP, "KP"),
})
// With a limit of one request a minute, the requests for paths under a
// prefix are not counted, so client's first request for / is within
// the limit; and once client has reached it, they are not refused.
s.request(client, "/assets/app.js", http.StatusOK, requestlog.ActionForward)
s.request(client, "/favicon.ico?v=2", http.StatusOK, requestlog.ActionForward)
s.get(client, http.StatusOK, requestlog.ActionForward)
line := s.request(client, "/assets/app.js", http.StatusOK, requestlog.ActionForward)
if line.LimitHit != "" || line.Counts != (ratelimit.Counts{}) {
t.Errorf("log line has limit_hit %q and counts %+v, want neither",
line.LimitHit, line.Counts)
}
// A path outside every prefix is counted: /assets is not under
// /assets/, and breaks the limit.
s.request(client, "/assets", http.StatusForbidden, requestlog.ActionRateLimited)
// A ban, SWWAF_DENY_NETS and the country lists still refuse a path
// under a prefix.
s.request(client, "/assets/app.js", http.StatusForbidden, requestlog.ActionBanned)
s.request(denied, "/assets/app.js", http.StatusForbidden, requestlog.ActionDenied)
s.request(fromKP, "/assets/app.js",
http.StatusForbidden, requestlog.ActionCountryDenied)
}
func TestRateLimitCountsPathsThatAreNotExempt(t *testing.T) {
t.Parallel()
for _, sent := range []string{
// A prefix matches only at the start of the path.
"/static/assets/app.js",
// A prefix matches the path as sent: a router that matches the
// path as received does not take /%61ssets/x for a path under
// /assets/.
"/%61ssets/x",
// .. once percent-decoded: an app may act on these as /login, the
// last as a path under /sneak/app/ or as /assets/x.
"/assets/../login",
"/assets/%2e%2e/login",
"/assets/..%2Flogin",
"/assets/..;/login",
"/sneak/app/src/branch/main/..%2F..%2F..%2F..%2F..%2F..%2Fassets/x",
// Not under /assets/ as sent: Go's router takes /assets%2Fx for one
// path segment, not a path under /assets/.
"/assets%2Fx",
"/assets%2fx",
// Under /assets/ as sent, but holding an encoded slash, in either
// case, or a backslash: never exempt, whatever the prefix.
"/assets/x%2Fy",
"/assets/x%2fy",
`/assets/x\y`,
} {
t.Run(sent, func(t *testing.T) {
t.Parallel()
s, _, _ := startWithClock(t, "", map[string]string{
rateLimitPerMinute: "1",
rateLimitExemptPaths: "/assets/",
})
// Counted, the second request breaks the limit of one request
// a minute.
s.request(client, sent, http.StatusOK, requestlog.ActionForward)
s.request(client, sent, http.StatusForbidden, requestlog.ActionRateLimited)
})
}
}
internal/proxy/request.go
+266 -45
View File
@@ -7,11 +7,15 @@ import (
"net/http/httptrace"
"net/http/httputil"
"net/netip"
"net/url"
"os"
"slices"
"strings"
"sync"
"sync/atomic"
"time"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
@@ -21,10 +25,13 @@ const flushAfterEachWrite time.Duration = -1
// refusal is smallwebwaf refusing a request, or refusing to go on with it:
// the status the client is answered if the response has not started yet,
// and the action the log line names.
// 0 to close the connection without an answer, the action the log line
// names, and the setting whose size or time limit the request passed, if
// that is why.
type refusal struct {
status int
action string
limit string
}
// request is one request on its way through smallwebwaf, from the moment
@@ -42,7 +49,9 @@ type request struct {
peer netip.Addr
peerTrusted bool
start time.Time
// upstreamStart is when the request was handed to the app.
// checked is when the checks were done, and upstreamStart when the
// request was handed to the app.
checked time.Time
upstreamStart time.Time
// cancel ends the request to the app.
cancel context.CancelFunc
@@ -52,24 +61,34 @@ type request struct {
complete bool
// mu guards what follows. The timeouts run on goroutines of their
// own, and the transport starts and stops them from its own; once
// timersStopped is set, none of them acts any more.
// own, and the transport starts and stops them, and notes the times
// below, from its own; once timersStopped is set, none of the timeouts
// acts any more.
mu sync.Mutex
timersStopped bool
clientRequestTimer *time.Timer
upstreamRequestTimer *time.Timer
upstreamResponseTimer *time.Timer
// requestSent is when the app had been sent the whole request.
requestSent time.Time
// connected is when there was a connection to the app, requestSent
// when the app had been sent the whole request, and answerStarted
// when the first byte of its answer arrived.
connected time.Time
requestSent time.Time
answerStarted time.Time
}
// newRequest starts handling r: it notes the time and works out the
// client.
// newRequest starts handling r: it notes the time, counts the request as
// under way, works out the client, and starts the log line with what is
// known of the request.
func (h *handler) newRequest(w http.ResponseWriter, r *http.Request) *request {
h.metrics.RequestStarted()
start := time.Now()
peer := peerAddress(r)
trusted := h.config.TrustedProxies
client := clientAddress(peer, r.Header.Values("X-Forwarded-For"), trusted)
peerTrusted := isInside(peer, trusted)
forwardedFor := r.Header.Values("X-Forwarded-For")
client := clientAddress(peer, forwardedFor, trusted)
rq := &request{
h: h,
@@ -78,22 +97,37 @@ func (h *handler) newRequest(w http.ResponseWriter, r *http.Request) *request {
out: &responseWriter{ResponseWriter: w},
client: client,
peer: peer,
peerTrusted: isInside(peer, trusted),
peerTrusted: peerTrusted,
start: start,
line: requestlog.Line{
Time: requestlog.FormatTime(start),
ClientIP: client.String(),
PeerIP: peer.String(),
Method: r.Method,
Host: r.Host,
Path: r.URL.EscapedPath(),
Query: r.URL.RawQuery,
Protocol: r.Proto,
Referer: r.Referer(),
UserAgent: r.UserAgent(),
Action: requestlog.ActionForward,
Time: requestlog.FormatTime(start),
Instance: h.config.InstanceName,
ClientIP: client.String(),
Method: r.Method,
Scheme: scheme(r, peerTrusted),
Host: r.Host,
Path: r.URL.EscapedPath(),
Query: r.URL.RawQuery,
Protocol: r.Proto,
Referer: r.Referer(),
UserAgent: r.UserAgent(),
RequestID: requestID(r, peerTrusted),
PeerIP: peer.String(),
ForwardedFor: strings.Join(forwardedFor, ", "),
ClientGroup: clientGroup(client).String(),
ContentType: r.Header.Get("Content-Type"),
RequestHeaders: requestHeaders(r, h.config.LogRequestHeaders),
HasAuthorization: len(r.Header.Values("Authorization")) > 0,
HasCookie: len(r.Header.Values("Cookie")) > 0,
Action: requestlog.ActionForward,
},
}
// A length of -1 is a body whose length was not announced.
if r.ContentLength > 0 {
rq.line.ContentLength = r.ContentLength
}
if r.Body != http.NoBody {
rq.body = &requestBody{body: limitBody(r.Body, h.config.RequestMaxBytes), rq: rq}
}
@@ -101,19 +135,44 @@ func (h *handler) newRequest(w http.ResponseWriter, r *http.Request) *request {
return rq
}
// requestHeaders returns the headers of r that names lists, by name in
// lower case, each with its values joined by ", ". Authorization, Cookie
// and Set-Cookie are never among them, whatever names says.
func requestHeaders(r *http.Request, names []string) map[string]string {
headers := map[string]string{}
for _, name := range names {
switch name {
case "authorization", "cookie", "set-cookie":
continue
}
values := r.Header.Values(name)
if len(values) > 0 {
headers[name] = strings.Join(values, ", ")
}
}
return headers
}
// check is the one place where a request can be refused once its client
// is known, before its body is read or anything reaches the app. It
// returns nil to let the request through. The rate limits come first, so
// that every request is counted, one refused for its size too.
func (rq *request) check() *refusal {
limitHit := rq.h.limiter.Count(clientGroup(rq.client), rq.start)
if limitHit != "" {
rq.line.LimitHit = limitHit
return &refusal{
status: http.StatusTooManyRequests,
action: requestlog.ActionRateLimited,
// returns nil to let the request through. The checks of checkClient come
// first, answered with SWWAF_BAN_RESPONSE, and then the size limit, so
// that a request the rate limits count is counted even when it is
// refused for its size. In observe mode a request checkClient refuses
// goes on to the size limit like any other. ctx is the request's own
// context.
func (rq *request) check(ctx context.Context) *refusal {
action := rq.checkClient(ctx)
if action != "" {
if !rq.h.config.Observe {
return rq.banResponse(action)
}
// The log line names what enforce mode would have done.
rq.line.WouldAction = action
}
maxBytes := rq.h.config.RequestMaxBytes
@@ -121,12 +180,76 @@ func (rq *request) check() *refusal {
return &refusal{
status: http.StatusRequestEntityTooLarge,
action: requestlog.ActionTooLarge,
limit: "SWWAF_REQUEST_MAX_BYTES",
}
}
return nil
}
// checkClient runs the checks on the request's client, and returns the
// action of the first that refuses the request, or "" when none does. A
// client in SWWAF_ALLOW_NETS skips them. For any other client,
// SWWAF_DENY_NETS comes first, then a ban on its netblock, so that a
// client either refuses is not looked up, and then the country lists; a
// request any of them refuses is not counted for the rate limits. Then
// come the rate limits, unless the client is in
// SWWAF_RATE_LIMIT_EXEMPT_NETS or the request's path is exempt under
// SWWAF_RATE_LIMIT_EXEMPT_PATHS, so that every other request is counted.
// ctx is the request's own context.
func (rq *request) checkClient(ctx context.Context) string {
cfg := rq.h.config
if isInside(rq.client, cfg.AllowNets) {
return ""
}
now := rq.h.now()
if isInside(rq.client, cfg.DenyNets) {
return requestlog.ActionDenied
}
if rq.banned(now) {
return requestlog.ActionBanned
}
if rq.countryDenied(ctx) {
return requestlog.ActionCountryDenied
}
exempt := isInside(rq.client, cfg.RateLimitExemptNets) ||
pathExempt(rq.in.URL, cfg.RateLimitExemptPaths)
if !exempt && rq.limitBroken(now) {
return requestlog.ActionRateLimited
}
return ""
}
// pathExempt reports whether the rate limits leave out a request for u
// because of SWWAF_RATE_LIMIT_EXEMPT_PATHS: whether its path as sent, the
// path the app receives, not percent-decoded, starts with one of
// prefixes, so that /%61ssets/x is not under /assets/ for an app whose
// router matches the path as received. A request whose decoded path
// contains .. anywhere or a backslash, or whose path as sent holds an
// encoded slash (%2F or %2f), never is, since an app may act on it as a
// path outside every prefix: /assets/..%2Flogin as /login, or /assets%2Fx
// as one path segment, as Go's router does.
func pathExempt(u *url.URL, prefixes []string) bool {
decoded := u.Path
// EscapedPath is the path as the app receives it, not decoded.
sent := u.EscapedPath()
if strings.Contains(decoded, "..") || strings.Contains(decoded, `\`) ||
strings.Contains(strings.ToLower(sent), "%2f") {
return false
}
return slices.ContainsFunc(prefixes, func(prefix string) bool {
return strings.HasPrefix(sent, prefix)
})
}
// forward passes the request to the app and the app's answer back. ctx
// is the request's own context.
func (rq *request) forward(ctx context.Context) {
@@ -135,7 +258,9 @@ func (rq *request) forward(ctx context.Context) {
rq.cancel = cancel
ctx = httptrace.WithClientTrace(ctx, &httptrace.ClientTrace{
WroteRequest: rq.wroteRequest,
GotConn: rq.gotConn,
WroteRequest: rq.wroteRequest,
GotFirstResponseByte: rq.gotFirstResponseByte,
})
out := rq.in.WithContext(ctx)
@@ -158,7 +283,8 @@ func (rq *request) forward(ctx context.Context) {
}
// rewrite makes the request the app receives: the client's request,
// unchanged, sent to SWWAF_UPSTREAM_URL, with the forwarded headers set.
// unchanged, sent to SWWAF_UPSTREAM_URL, with the forwarded headers and
// the request's id set.
func (rq *request) rewrite(pr *httputil.ProxyRequest) {
upstream := rq.h.config.UpstreamURL
pr.Out.URL.Scheme = upstream.Scheme
@@ -167,6 +293,7 @@ func (rq *request) rewrite(pr *httputil.ProxyRequest) {
// the query as the client sent it.
pr.Out.URL.RawQuery = pr.In.URL.RawQuery
setForwardedHeaders(pr.In, pr.Out, rq.peer, rq.peerTrusted)
pr.Out.Header.Set(requestIDHeader, rq.line.RequestID)
}
// modifyResponse looks at the app's answer before ReverseProxy passes it
@@ -180,13 +307,18 @@ func (rq *request) modifyResponse(res *http.Response) error {
// connection it takes over, not through rq.out.
rq.stopTimers()
rq.out.status = res.StatusCode
rq.line.Websocket = true
return nil
}
maxBytes := rq.h.config.ResponseMaxBytes
if maxBytes > 0 && res.Body != http.NoBody && res.ContentLength > maxBytes {
rq.refuse(refusal{status: http.StatusBadGateway, action: requestlog.ActionTooLarge})
rq.refuse(refusal{
status: http.StatusBadGateway,
action: requestlog.ActionTooLarge,
limit: "SWWAF_RESPONSE_MAX_BYTES",
})
return errResponseTooLarge
}
@@ -226,6 +358,13 @@ func (rq *request) answer(r refusal) {
return // too late to answer: the connection can only be cut
}
if r.status == 0 {
// SWWAF_BAN_RESPONSE is close. This panic has Go's server close
// the connection without an answer, and log nothing; the log line
// is still written as the handler returns.
panic(http.ErrAbortHandler)
}
// A client found too slow is read no more; any other may go on
// sending until its time is up, so that Go's server can read the
// rest of the body and end the request cleanly.
@@ -251,7 +390,8 @@ func (rq *request) refuse(r refusal) {
rq.cancel()
}
// finish ends the request's timeouts and writes its log line.
// finish ends the request's timeouts, counts it in the metrics and writes
// its log line.
func (rq *request) finish() {
rq.stopTimers()
@@ -263,35 +403,90 @@ func (rq *request) finish() {
line := &rq.line
line.Status = rq.out.status
line.ResponseBytes = rq.out.bytes
header := rq.out.Header()
line.ResponseContentType = header.Get("Content-Type")
line.CacheControl = header.Get("Cache-Control")
line.Location = header.Get("Location")
if rq.body != nil {
line.RequestBytes = rq.body.bytes.Load()
}
// limit is the setting whose size or time limit the request passed.
var limit string
switch {
case refused != nil:
line.Action = refused.action
limit = refused.limit
case errors.Is(rq.out.err, os.ErrDeadlineExceeded):
// The client took longer than SWWAF_CLIENT_RESPONSE_TIMEOUT to
// take the response.
line.Action = requestlog.ActionTimedOut
limit = "SWWAF_CLIENT_RESPONSE_TIMEOUT"
case !rq.complete && (rq.out.err != nil || rq.in.Context().Err() != nil):
line.Aborted = true
}
now := time.Now()
line.DurationTotal = requestlog.Milliseconds(now.Sub(rq.start))
duration := now.Sub(rq.start)
line.DurationTotal = requestlog.Milliseconds(duration)
line.DurationChecks = timing(rq.start, rq.checked)
var upstreamDuration time.Duration
if !rq.upstreamStart.IsZero() {
line.DurationUpstreamTotal = requestlog.Milliseconds(now.Sub(rq.upstreamStart))
upstreamDuration = now.Sub(rq.upstreamStart)
line.DurationUpstreamTotal = new(requestlog.Milliseconds(upstreamDuration))
rq.mu.Lock()
line.DurationUpstreamConnect = timing(rq.upstreamStart, rq.connected)
line.DurationUpstreamFirstByte = timing(rq.upstreamStart, rq.answerStarted)
rq.mu.Unlock()
}
// Counted before the log line is written, so that the metrics count
// every request whose line is out.
rq.h.metrics.RequestEnded(line, limit, duration, upstreamDuration)
err := requestlog.Write(rq.h.requestLog, line)
if err != nil {
rq.h.processLog.Error("writing the request log failed", "error", err.Error())
}
}
// timing is the time from start to end in milliseconds, for one of the
// log line's timings, or nil when end is zero: what it times never
// happened.
func timing(start, end time.Time) *float64 {
if end.IsZero() {
return nil
}
return new(requestlog.Milliseconds(end.Sub(start)))
}
// addToHistory adds the request, which has ended, to its client's
// history.
func (rq *request) addToHistory() {
var requestBytes int64
if rq.body != nil {
requestBytes = rq.body.bytes.Load()
}
forwarded := !rq.upstreamStart.IsZero()
rq.h.limiter.AddToHistory(clientGroup(rq.client), rq.h.now(), ratelimit.Request{
Country: rq.line.Country,
Forwarded: forwarded,
Refused: !forwarded && rq.refused.Load() != nil,
Status: rq.out.status,
RequestBytes: requestBytes,
ResponseBytes: rq.out.bytes,
BrokeLimit: rq.line.Offence == requestlog.OffenceLimit,
})
}
// clientRequestDeadline is when the client must have sent its whole
// request, or zero when SWWAF_CLIENT_REQUEST_TIMEOUT is off.
func (rq *request) clientRequestDeadline() time.Time {
@@ -324,21 +519,26 @@ func (rq *request) startRequestTimers() {
if rq.body != nil && rq.h.config.ClientRequestTimeout > 0 {
rq.clientRequestTimer = time.AfterFunc(
time.Until(rq.clientRequestDeadline()), rq.requestTimedOut)
time.Until(rq.clientRequestDeadline()), func() {
rq.requestTimedOut("SWWAF_CLIENT_REQUEST_TIMEOUT")
})
}
timeout := rq.h.config.UpstreamRequestTimeout
if timeout > 0 {
rq.upstreamRequestTimer = time.AfterFunc(timeout, rq.requestTimedOut)
rq.upstreamRequestTimer = time.AfterFunc(timeout, func() {
rq.requestTimedOut("SWWAF_UPSTREAM_REQUEST_TIMEOUT")
})
}
}
// requestTimedOut is called when a request timeout runs out while the
// request is still on its way to the app. The answer names the side
// smallwebwaf was waiting on at that moment: 408 when it was waiting for
// the client to send more of its body, 504 when it was waiting for the
// app to be reached or to take what it had.
func (rq *request) requestTimedOut() {
// requestTimedOut is called when limit, SWWAF_CLIENT_REQUEST_TIMEOUT or
// SWWAF_UPSTREAM_REQUEST_TIMEOUT, runs out while the request is still on
// its way to the app. The answer names the side smallwebwaf was waiting
// on at that moment: 408 when it was waiting for the client to send more
// of its body, 504 when it was waiting for the app to be reached or to
// take what it had.
func (rq *request) requestTimedOut(limit string) {
rq.mu.Lock()
defer rq.mu.Unlock()
@@ -350,6 +550,7 @@ func (rq *request) requestTimedOut() {
rq.refuse(refusal{
status: http.StatusGatewayTimeout,
action: requestlog.ActionTimedOut,
limit: limit,
})
return
@@ -358,6 +559,7 @@ func (rq *request) requestTimedOut() {
rq.refuse(refusal{
status: http.StatusRequestTimeout,
action: requestlog.ActionTimedOut,
limit: limit,
})
// The transport gives up on the app only once its Read of the
// client's body returns, so that Read is ended now. The lock keeps
@@ -373,6 +575,24 @@ func (rq *request) bodyReceived() {
stopTimer(rq.clientRequestTimer)
}
// gotConn is called once there is a connection to the app, a new one or
// one kept open from an earlier request.
func (rq *request) gotConn(httptrace.GotConnInfo) {
rq.mu.Lock()
defer rq.mu.Unlock()
rq.connected = time.Now()
}
// gotFirstResponseByte is called once the first byte of the app's answer
// has arrived.
func (rq *request) gotFirstResponseByte() {
rq.mu.Lock()
defer rq.mu.Unlock()
rq.answerStarted = time.Now()
}
// wroteRequest is called once the app has been sent the whole request:
// the request timeouts end and SWWAF_UPSTREAM_RESPONSE_TIMEOUT starts.
func (rq *request) wroteRequest(info httptrace.WroteRequestInfo) {
@@ -407,6 +627,7 @@ func (rq *request) responseTimedOut() {
rq.refuse(refusal{
status: http.StatusGatewayTimeout,
action: requestlog.ActionTimedOut,
limit: "SWWAF_UPSTREAM_RESPONSE_TIMEOUT",
})
}
}
internal/proxy/requestlog_test.go
+368
View File
@@ -0,0 +1,368 @@
package proxy_test
import (
"io"
"maps"
"math"
"net/http"
"reflect"
"slices"
"strings"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
const (
// requestIDHeader carries the request's id.
requestIDHeader = "X-Request-ID"
// instance is the SWWAF_INSTANCE_NAME a test sets.
instance = "fsn1app1/gitea"
// ipv6Client is a client on IPv6, and ipv6Group the netblock the rate
// limits count it as.
ipv6Client = "2001:db8::7"
ipv6Group = "2001:db8::/64"
)
func TestLogLineHasEachFieldWhereItApplies(t *testing.T) {
t.Parallel()
received := make(chan string, 2) // the request ids the app received
app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
received <- r.Header.Get(requestIDHeader)
_, _ = io.Copy(io.Discard, r.Body)
if r.URL.Path != "/full" {
w.WriteHeader(http.StatusNoContent)
return
}
w.Header().Set("Content-Type", "text/html")
w.Header().Set("Cache-Control", "no-store")
w.Header().Set("Location", "/elsewhere")
w.WriteHeader(http.StatusFound)
_, _ = io.WriteString(w, "moved")
})
addr, out := startProxy(t, app.URL, map[string]string{
trustedProxies: trustLocalhost,
rateLimitExemptNets: localhost,
instanceName: instance,
logRequestHeaders: "Accept,x-custom,Authorization,cookie,SET-COOKIE",
})
// This request comes from ipv6Client through a trusted proxy, with a
// body and each header the log line looks at, and is answered with a
// redirect.
conn := dial(t, addr)
send(t, conn, "POST /full HTTP/1.1\r\nHost: "+appHost+"\r\n"+
forwardedFor+": 198.51.100.7, "+ipv6Client+"\r\n"+
forwardedProto+": "+secure+"\r\n"+requestIDHeader+": from-traefik\r\n"+
"Content-Type: application/x-www-form-urlencoded\r\nContent-Length: 3\r\n"+
"Accept: text/html\r\nX-Custom: one\r\nX-Custom: two\r\n"+
"Authorization: Bearer secret-token\r\nCookie: session=secret-cookie\r\n"+
"Set-Cookie: secret-set-cookie\r\n\r\na=b")
wantStatus(t, readResponse(t, conn), http.StatusFound)
// A request's log line can come after its answer: each is waited for
// before the next request, so that the lines are in order.
full := out.requestLines(t, 1)[0]
// This one comes from 127.0.0.1, which the rate limits do not count,
// with a body of 4 bytes whose length it does not announce, so that its
// request_bytes is not its content_length, and no header the log line
// looks at, and is answered with 204 and no header.
conn = dial(t, addr)
send(t, conn, "POST /bare HTTP/1.1\r\nHost: "+appHost+"\r\n"+
"Transfer-Encoding: chunked\r\n\r\n4\r\nbody\r\n0\r\n\r\n")
wantStatus(t, readResponse(t, conn), http.StatusNoContent)
bare := out.requestLines(t, 2)[1]
wantFullLine(t, full)
wantBareLine(t, bare)
for _, line := range []logLine{full, bare} {
got := <-received
if got != line.RequestID {
t.Errorf("the app received request id %q, the log line has %q",
got, line.RequestID)
}
}
if strings.Contains(out.text(), "secret") {
t.Errorf("a value of Authorization, Cookie or Set-Cookie is logged:\n%s",
out.text())
}
}
// wantFullLine checks the log line of the request with every header the
// line looks at. Its timings are checked by TestTimingsAreInOrder.
func wantFullLine(t *testing.T, line logLine) {
t.Helper()
headers := map[string]string{"accept": "text/html", "x-custom": "one, two"}
want := withTimings(line, requestlog.Line{
Type: requestType, Time: line.Time, Instance: instance,
ClientIP: ipv6Client, Method: http.MethodPost, Scheme: secure,
Host: appHost, Path: "/full", Protocol: protocol,
Status: http.StatusFound, RequestBytes: 3, ResponseBytes: 5,
RequestID: "from-traefik", PeerIP: localhost,
ForwardedFor: "198.51.100.7, " + ipv6Client, ClientGroup: ipv6Group,
ContentType: "application/x-www-form-urlencoded", ContentLength: 3,
RequestHeaders: headers, HasAuthorization: true, HasCookie: true,
ResponseContentType: "text/html", UpstreamStatus: http.StatusFound,
CacheControl: "no-store", Location: "/elsewhere",
Action: requestlog.ActionForward,
Counts: ratelimit.Counts{Minute: 1, Hour: 1, Day: 1},
})
if !reflect.DeepEqual(line.Line, want) {
t.Errorf("log line\n%+v\nwant\n%+v", line.Line, want)
}
}
// wantBareLine checks the log line of the request with none of them, and
// that the fields that do not apply to it are left out.
func wantBareLine(t *testing.T, line logLine) {
t.Helper()
want := withTimings(line, requestlog.Line{
Type: requestType, Time: line.Time, Instance: instance,
ClientIP: localhost, Method: http.MethodPost, Scheme: plain,
Host: appHost, Path: "/bare", Protocol: protocol,
Status: http.StatusNoContent, RequestBytes: 4, RequestID: line.RequestID,
PeerIP: localhost, ClientGroup: localhost + "/32",
UpstreamStatus: http.StatusNoContent, Action: requestlog.ActionForward,
})
if !reflect.DeepEqual(line.Line, want) || line.RequestID == "" {
t.Errorf("log line\n%+v\nwant\n%+v, with a request id", line.Line, want)
}
for _, name := range []string{
"forwarded_for", "content_type", "content_length", "request_headers",
"has_authorization", "has_cookie", "websocket", "response_content_type",
"cache_control", "location", "counts",
} {
_, present := line.fields[name]
if present {
t.Errorf("log line has %s, which does not apply", name)
}
}
}
// withTimings returns want with the timings of line.
func withTimings(line logLine, want requestlog.Line) requestlog.Line {
want.DurationTotal = line.DurationTotal
want.DurationChecks = line.DurationChecks
want.DurationUpstreamConnect = line.DurationUpstreamConnect
want.DurationUpstreamFirstByte = line.DurationUpstreamFirstByte
want.DurationUpstreamTotal = line.DurationUpstreamTotal
return want
}
func TestHasAuthorizationAndHasCookieEachComeFromTheirOwnHeader(t *testing.T) {
t.Parallel()
const hasAuthorization, hasCookie = "has_authorization", "has_cookie"
for _, tc := range []struct{ header, field, other string }{
{"Authorization", hasAuthorization, hasCookie},
{"Cookie", hasCookie, hasAuthorization},
} {
t.Run("only "+tc.header, func(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, out := startProxy(t, app.URL, nil)
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
req.Header.Set(tc.header, "secret")
wantStatus(t, do(t, req), http.StatusOK)
line := out.requestLine(t)
_, otherPresent := line.fields[tc.other]
if line.fields[tc.field] != true || otherPresent {
t.Errorf("log line has %s %v and %s %v, want true and none",
tc.field, line.fields[tc.field], tc.other, line.fields[tc.other])
}
})
}
}
func TestRequestIDAndSchemeComeOnlyFromATrustedProxy(t *testing.T) {
t.Parallel()
const sentID = "from-traefik"
sent := http.Header{requestIDHeader: {sentID}, forwardedProto: {secure}}
trusted := map[string]string{trustedProxies: trustLocalhost}
for _, tc := range []struct {
name string
env map[string]string
header http.Header
// wantID is the request id logged, "" for a new one.
wantID, wantScheme string
}{
{"a trusted proxy's are kept", trusted, sent, sentID, secure},
{"without them, the id is new and the scheme http", trusted, nil, "", plain},
{"another peer's are replaced", nil, sent, "", plain},
} {
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
received := make(chan string, 2)
app := startApp(t, func(_ http.ResponseWriter, r *http.Request) {
received <- r.Header.Get(requestIDHeader)
})
addr, out := startProxy(t, app.URL, tc.env)
// Two requests, so that two new ids can be told apart.
ids := make([]string, 0, 2)
for i := range 2 {
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
maps.Copy(req.Header, tc.header)
wantStatus(t, do(t, req), http.StatusOK)
line := out.requestLines(t, i+1)[i]
ids = append(ids, line.RequestID)
got := <-received
if line.RequestID != got || line.Scheme != tc.wantScheme {
t.Errorf("log line has request_id %q and scheme %q, and the "+
"app received id %q; want the same id and scheme %q",
line.RequestID, line.Scheme, got, tc.wantScheme)
}
}
switch {
case tc.wantID != "" && (ids[0] != tc.wantID || ids[1] != tc.wantID):
t.Errorf("request ids %q, want %q", ids, tc.wantID)
case tc.wantID == "" && (slices.Contains(ids, sentID) ||
slices.Contains(ids, "") || ids[0] == ids[1]):
t.Errorf("request ids %q, want two new ones", ids)
}
})
}
}
func TestTimingsAreInOrder(t *testing.T) {
t.Parallel()
const denied = "192.0.2.50" // in SWWAF_DENY_NETS
app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
// The pauses set the times apart; a hold-up of the test only
// lengthens them.
time.Sleep(time.Millisecond)
w.WriteHeader(http.StatusOK)
_ = http.NewResponseController(w).Flush()
time.Sleep(time.Millisecond)
_, _ = io.WriteString(w, "done")
})
addr, out := startProxy(t, app.URL, map[string]string{
trustedProxies: trustLocalhost,
denyNets: denied,
})
// Each log line is waited for before the next request, so that the
// lines are in order.
wantStatus(t, get(t, addr, "/"), http.StatusOK)
forwarded := out.requestLines(t, 1)[0]
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
req.Header.Set(forwardedFor, denied)
wantStatus(t, do(t, req), http.StatusForbidden)
refused := out.requestLines(t, 2)[1]
wantStatus(t, get(t, addr, proxy.HealthPath), http.StatusOK)
health := out.requestLines(t, 3)[2]
// A request passed to the app has every timing; one refused, none of
// the app's; the health check, which runs no check, only the total.
wantTimings(t, forwarded, "duration_total", "duration_checks",
"duration_upstream_connect", "duration_upstream_first_byte",
"duration_upstream_total")
wantTimings(t, refused, "duration_total", "duration_checks")
wantTimings(t, health, "duration_total")
if t.Failed() {
return
}
// In whole microseconds, as they are logged, so that the sum below is
// exact.
total := microseconds(forwarded.DurationTotal)
checks := microseconds(*forwarded.DurationChecks)
connect := microseconds(*forwarded.DurationUpstreamConnect)
firstByte := microseconds(*forwarded.DurationUpstreamFirstByte)
upstream := microseconds(*forwarded.DurationUpstreamTotal)
// The checks end before the request is handed to the app, and the
// connection comes before the answer, which the app ends after a
// pause.
if checks+upstream > total || connect >= firstByte || firstByte >= upstream {
t.Errorf("timings in microseconds: total %d, checks %d, connect %d, "+
"first byte %d, upstream total %d", total, checks, connect, firstByte,
upstream)
}
if *refused.DurationChecks > refused.DurationTotal {
t.Errorf("refused request's checks took %v of %v milliseconds",
*refused.DurationChecks, refused.DurationTotal)
}
}
// wantTimings checks that the timings named are the only ones line has.
func wantTimings(t *testing.T, line logLine, want ...string) {
t.Helper()
var got []string
for name := range line.fields {
if strings.HasPrefix(name, "duration_") {
got = append(got, name)
}
}
slices.Sort(got)
slices.Sort(want)
if !slices.Equal(got, want) {
t.Errorf("log line of %s has timings %v, want %v", line.Path, got, want)
}
}
// microseconds is a timing in whole microseconds.
func microseconds(milliseconds float64) int64 {
return int64(math.Round(milliseconds * 1000))
}
func TestLogsAnUpgradedConnection(t *testing.T) {
t.Parallel()
app := startApp(t, echoAfterUpgrade)
addr, out := startProxy(t, app.URL, nil)
conn := dial(t, addr)
send(t, conn, "GET /socket HTTP/1.1\r\nHost: app\r\n"+
"Connection: Upgrade\r\nUpgrade: websocket\r\n\r\n")
wantStatus(t, readResponse(t, conn), http.StatusSwitchingProtocols)
_ = conn.Close()
line := out.requestLine(t)
if line.fields["websocket"] != true {
t.Errorf("log line has websocket %v, want true", line.fields["websocket"])
}
}
internal/proxy/staticlists_test.go
+184
View File
@@ -0,0 +1,184 @@
package proxy_test
import (
"net/http"
"strings"
"sync/atomic"
"testing"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
)
// The rate limits count an IPv6 client by its /64, so these two addresses
// are one client for them. The static lists match each address on its own,
// and the tests list listedAddr alone.
const (
listedAddr = "2001:db8::1"
unlistedAddr = "2001:db8::2"
)
func TestAllowNetsSkipEveryCheckButTheSizeLimit(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
geojsURL, asked := startGeoJS(t)
// fromKP is in SWWAF_ALLOW_NETS, and in SWWAF_DENY_NETS too, which
// comes after it.
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
trustedProxies: trustLocalhost,
allowNets: "198.51.100.0/24",
denyNets: fromKP,
deniedCountries: "kp",
rateLimitPerMinute: "1",
requestMaxBytes: "1K",
})
// Neither SWWAF_DENY_NETS, the country lists nor the limit of one
// request a minute refuses the client, and its country is not looked
// up.
wantAnswers(t, addr, out, []sentRequest{
{fromKP, http.StatusOK, requestlog.ActionForward},
{fromKP, http.StatusOK, requestlog.ActionForward},
})
if len(asked()) != 0 {
t.Errorf("GeoJS was asked about %v, want nothing", asked())
}
// The size limit still applies.
body := strings.NewReader(strings.Repeat("a", 2<<10))
req := newRequest(t, http.MethodPost, addr, "/", body)
req.Header.Set(forwardedFor, fromKP)
wantStatus(t, do(t, req), http.StatusRequestEntityTooLarge)
wantLine(t, out.requestLines(t, 3)[2],
http.StatusRequestEntityTooLarge, requestlog.ActionTooLarge)
if calls.Load() != 2 {
t.Errorf("the app was called %d times, want 2", calls.Load())
}
}
func TestRequestFromAllowNetsIsNotCounted(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, out := startProxy(t, app.URL, map[string]string{
trustedProxies: trustLocalhost,
allowNets: listedAddr,
rateLimitPerMinute: "1",
})
// listedAddr's requests are not counted, so the first request from
// unlistedAddr is within the limit of one a minute.
wantAnswers(t, addr, out, []sentRequest{
{listedAddr, http.StatusOK, requestlog.ActionForward},
{listedAddr, http.StatusOK, requestlog.ActionForward},
{unlistedAddr, http.StatusOK, requestlog.ActionForward},
{unlistedAddr, http.StatusForbidden, requestlog.ActionRateLimited},
})
}
func TestDenyNetsRefuseBeforeTheLookupAndTheBody(t *testing.T) {
t.Parallel()
var calls atomic.Int32
app := startApp(t, func(http.ResponseWriter, *http.Request) {
calls.Add(1)
})
geojsURL, asked := startGeoJS(t)
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
trustedProxies: trustLocalhost,
denyNets: "203.0.113.0/24",
deniedCountries: "kp",
})
req := newRequest(t, http.MethodPost, addr, "/", strings.NewReader("a body"))
req.Header.Set(forwardedFor, fromDE)
wantStatus(t, do(t, req), http.StatusForbidden)
line := out.requestLine(t)
wantLine(t, line, http.StatusForbidden, requestlog.ActionDenied)
if line.RequestBytes != 0 {
t.Errorf("log line has request_bytes %d, want 0", line.RequestBytes)
}
if len(asked()) != 0 {
t.Errorf("GeoJS was asked about %v, want nothing", asked())
}
if calls.Load() != 0 {
t.Errorf("the app was called %d times, want none", calls.Load())
}
}
func TestRequestRefusedByDenyNetsIsNotCounted(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, out := startProxy(t, app.URL, map[string]string{
trustedProxies: trustLocalhost,
denyNets: listedAddr,
rateLimitPerMinute: "1",
})
// listedAddr's refused requests are not counted, so the first request
// from unlistedAddr is within the limit of one a minute.
wantAnswers(t, addr, out, []sentRequest{
{listedAddr, http.StatusForbidden, requestlog.ActionDenied},
{listedAddr, http.StatusForbidden, requestlog.ActionDenied},
{unlistedAddr, http.StatusOK, requestlog.ActionForward},
{unlistedAddr, http.StatusForbidden, requestlog.ActionRateLimited},
})
}
func TestRateLimitExemptNetsAreNeitherCountedNorRefused(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
geojsURL, _ := startGeoJS(t)
addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
trustedProxies: trustLocalhost,
rateLimitExemptNets: listedAddr + "," + fromKP,
deniedCountries: "kp",
rateLimitPerMinute: "1",
})
// listedAddr's requests are neither refused nor counted, so the first
// request from unlistedAddr is within the limit of one a minute. The
// country lists still refuse an exempt client.
wantAnswers(t, addr, out, []sentRequest{
{listedAddr, http.StatusOK, requestlog.ActionForward},
{listedAddr, http.StatusOK, requestlog.ActionForward},
{unlistedAddr, http.StatusOK, requestlog.ActionForward},
{unlistedAddr, http.StatusForbidden, requestlog.ActionRateLimited},
{fromKP, http.StatusForbidden, requestlog.ActionCountryDenied},
})
}
// sentRequest is a GET request from client, as X-Forwarded-For names it,
// and the status and log line action it should get.
type sentRequest struct {
client string
status int
action string
}
// wantAnswers sends requests to smallwebwaf at addr one after another and
// checks each one's answer and log line. They must be the first requests
// smallwebwaf is sent, since the log lines are matched to them in order.
func wantAnswers(t *testing.T, addr string, out *output, requests []sentRequest) {
t.Helper()
for i, sent := range requests {
req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
req.Header.Set(forwardedFor, sent.client)
wantStatus(t, do(t, req), sent.status)
wantLine(t, out.requestLines(t, i+1)[i], sent.status, sent.action)
}
}
internal/proxy/timeouts_test.go
+77 -31
View File
@@ -5,8 +5,10 @@ import (
"io"
"net"
"net/http"
"net/http/httptest"
"strconv"
"sync"
"sync/atomic"
"testing"
"time"
@@ -26,41 +28,36 @@ func TestRequestTimeouts(t *testing.T) {
for _, tc := range []struct {
name string
env map[string]string
// limit is the setting set to shortTimeout, which runs out; long
// is one set to longTimeoutSetting, which does not, or "".
limit, long string
// appTakesNothing has the app never read, while the client sends
// as fast as it can; otherwise the app reads, and the client
// stops sending halfway. smallwebwaf then waits on the client
// only once it has connected to the app and passed on the first
// bytes; a test process held up for shortTimeout before that
// gets 504, which is the right answer, and the case fails.
// stops sending halfway.
appTakesNothing bool
want int
}{
{
name: "client request timeout, waiting on the client",
env: map[string]string{clientRequestTimeout: shortTimeoutSetting},
want: http.StatusRequestTimeout,
name: "client request timeout, waiting on the client",
limit: clientRequestTimeout,
want: http.StatusRequestTimeout,
},
{
name: "upstream request timeout, waiting on the client",
env: map[string]string{
upstreamRequestTimeout: shortTimeoutSetting,
clientRequestTimeout: longTimeoutSetting,
},
want: http.StatusRequestTimeout,
name: "upstream request timeout, waiting on the client",
limit: upstreamRequestTimeout,
long: clientRequestTimeout,
want: http.StatusRequestTimeout,
},
{
name: "upstream request timeout, waiting on the app",
env: map[string]string{upstreamRequestTimeout: shortTimeoutSetting},
limit: upstreamRequestTimeout,
appTakesNothing: true,
want: http.StatusGatewayTimeout,
},
{
name: "client request timeout, waiting on the app",
env: map[string]string{
clientRequestTimeout: shortTimeoutSetting,
upstreamRequestTimeout: longTimeoutSetting,
},
name: "client request timeout, waiting on the app",
limit: clientRequestTimeout,
long: upstreamRequestTimeout,
appTakesNothing: true,
want: http.StatusGatewayTimeout,
},
@@ -69,32 +66,53 @@ func TestRequestTimeouts(t *testing.T) {
t.Parallel()
var (
app *httptest.Server
appURL string
sendRequest func(*testing.T, string) net.Conn
appGotBody atomic.Bool
)
if tc.appTakesNothing {
appURL, sendRequest = startAppThatTakesNothing(t), sendLargeBody
} else {
appURL, sendRequest = startApp(t, readBody).URL, sendPartOfBody
app = startApp(t, func(_ http.ResponseWriter, r *http.Request) {
n, _ := io.Copy(io.Discard, r.Body)
appGotBody.Store(n > 0)
})
appURL, sendRequest = app.URL, sendPartOfBody
}
addr, out := startProxy(t, appURL, tc.env)
start := time.Now()
conn := sendRequest(t, addr)
env := map[string]string{tc.limit: shortTimeoutSetting, metricsToken: token}
if tc.long != "" {
env[tc.long] = longTimeoutSetting
}
wantStatus(t, readResponse(t, conn), tc.want)
addr, out := startProxy(t, appURL, env)
start := time.Now()
got := readResponse(t, sendRequest(t, addr))
wantTimedOut(t, start)
wantLine(t, out.requestLine(t), tc.want, requestlog.ActionTimedOut)
want := tc.want
if app != nil {
// Close returns once the app has finished with the request.
app.Close()
// Until some of the body has reached the app, smallwebwaf
// waits on the app, and SPEC.md asks for 504; the timeout
// runs out then only if the test process is held up.
if !appGotBody.Load() {
want = http.StatusGatewayTimeout
}
}
wantStatus(t, got, want)
wantLine(t, out.requestLine(t), want, requestlog.ActionTimedOut)
wantLimitHits(t, addr, tc.limit, 1)
})
}
}
// readBody is an app that reads the request body, then answers.
func readBody(_ http.ResponseWriter, r *http.Request) {
_, _ = io.Copy(io.Discard, r.Body)
}
// startAppThatTakesNothing starts an app that accepts connections and
// never reads from them, and returns its URL.
func startAppThatTakesNothing(t *testing.T) string {
@@ -184,6 +202,7 @@ func TestAppTooSlowToAnswer(t *testing.T) {
})
addr, out := startProxy(t, app.URL, map[string]string{
upstreamResponseTimeout: shortTimeoutSetting,
metricsToken: token,
})
start := time.Now()
@@ -199,6 +218,8 @@ func TestAppTooSlowToAnswer(t *testing.T) {
t.Errorf("log line has upstream_status %v for an app that never answered",
line.fields["upstream_status"])
}
wantLimitHits(t, addr, upstreamResponseTimeout, 1)
}
func TestAppTooSlowToFinishItsAnswer(t *testing.T) {
@@ -247,6 +268,7 @@ func TestClientTooSlowToTakeTheAnswer(t *testing.T) {
})
addr, out := startProxy(t, app.URL, map[string]string{
clientResponseTimeout: shortTimeoutSetting,
metricsToken: token,
})
start := time.Now()
@@ -258,4 +280,28 @@ func TestClientTooSlowToTakeTheAnswer(t *testing.T) {
line := out.requestLine(t)
wantTimedOut(t, start)
wantLine(t, line, http.StatusOK, requestlog.ActionTimedOut)
wantLimitHits(t, addr, clientResponseTimeout, 1)
}
func TestClosesAnIdleConnection(t *testing.T) {
t.Parallel()
app := startApp(t, func(http.ResponseWriter, *http.Request) {})
addr, _ := startProxy(t, app.URL, map[string]string{
clientIdleTimeout: shortTimeoutSetting,
})
// The idle time starts once the answer is sent, so after start.
start := time.Now()
conn := dial(t, addr)
send(t, conn, "GET / HTTP/1.1\r\nHost: app\r\n\r\n")
wantStatus(t, readResponse(t, conn), http.StatusOK)
// The read deadline readResponse set still bounds this read.
_, err := conn.Read(make([]byte, 1))
if !errors.Is(err, io.EOF) {
t.Fatalf("read on the idle connection: %v, want it closed", err)
}
wantTimedOut(t, start)
}
internal/ratelimit/history_test.go
+119
View File
@@ -0,0 +1,119 @@
package ratelimit_test
import (
"net/netip"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
)
func TestHistoryKeepsEveryRequest(t *testing.T) {
t.Parallel()
limiter := ratelimit.New(ratelimit.Limits{})
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
for i, r := range []ratelimit.Request{
{Country: "DE", Forwarded: true, Status: 200, RequestBytes: 10, ResponseBytes: 100},
{Forwarded: true, Status: 101},
{Forwarded: true, Status: 304, RequestBytes: 5},
{Country: "FR", Refused: true, Status: 403, ResponseBytes: 10, BrokeLimit: true},
{Forwarded: true, Status: 502, ResponseBytes: 12},
// Closed without an answer: refused, and no response.
{Refused: true, Status: 0},
// Answered 404 at smallwebwaf's own endpoints: neither forwarded
// nor refused.
{Status: 404},
} {
limiter.AddToHistory(client, start.Add(time.Duration(i)*time.Minute), r)
}
want := ratelimit.History{
FirstSeen: start,
LastSeen: start.Add(6 * time.Minute),
Country: "FR",
LookedUp: start.Add(3 * time.Minute),
Requests: 7,
Forwarded: 4,
Refused: 2,
RequestBytes: 15,
ResponseBytes: 122,
Responses: ratelimit.Responses{
Status1xx: 1, Status2xx: 1, Status3xx: 1, Status4xx: 2, Status5xx: 1,
},
Offences: ratelimit.Offences{Limit: 1},
}
got := historyOf(t, limiter, client)
if got != want {
t.Errorf("history\n%+v\nwant\n%+v", got, want)
}
}
func TestResetKeepsTheHistory(t *testing.T) {
t.Parallel()
limiter := ratelimit.New(ratelimit.Limits{PerMinute: limit})
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
for range limit {
wantCount(t, limiter, client, start, "")
limiter.AddToHistory(client, start, ratelimit.Request{Forwarded: true})
}
limiter.Reset(client)
if got := historyOf(t, limiter, client).Requests; got != limit {
t.Errorf("the history counts %d requests, want %d", got, limit)
}
}
func TestRequestsAddsUpTheClientsInsideTheNetblock(t *testing.T) {
t.Parallel()
limiter := ratelimit.New(ratelimit.Limits{})
for client, requests := range map[string]int{
"198.51.100.9/32": 2,
"198.51.100.10/32": 3,
"192.0.2.1/32": 5,
"2001:db8:5::/64": 7,
} {
for range requests {
limiter.AddToHistory(netip.MustParsePrefix(client), midnight(),
ratelimit.Request{})
}
}
for netblock, want := range map[string]int64{
"198.51.100.9/32": 2,
"198.51.100.0/24": 5,
"2001:db8:5::/64": 7,
"203.0.113.0/24": 0,
} {
got := limiter.Requests(netip.MustParsePrefix(netblock))
if got != want {
t.Errorf("%s has sent %d requests, want %d", netblock, got, want)
}
}
}
// historyOf returns client's history.
func historyOf(
t *testing.T, limiter *ratelimit.Limiter, client netip.Prefix,
) ratelimit.History {
t.Helper()
for _, c := range limiter.Snapshot() {
if c.Client == client {
return c.History
}
}
t.Fatalf("%s is not in the table", client)
return ratelimit.History{}
}
internal/ratelimit/ratelimit.go
+304 -47
View File
@@ -1,11 +1,15 @@
// Package ratelimit counts each client's requests over a minute, an hour
// and a day, as the "Counting method" section of SPEC.md describes, and
// tells when a request takes a client over a rate limit. The counts are
// kept in memory only, for at most 20,000 clients.
// Package ratelimit keeps the table of clients: each client's requests
// counted over a minute, an hour and a day, as the "Counting method"
// section of SPEC.md describes, which tell when a request takes the client
// over a rate limit, and each client's history since it was first seen.
// At most 20,000 clients are kept, in memory, and written to clients.json
// and read from it by the state package.
package ratelimit
import (
"net/http"
"net/netip"
"slices"
"sync"
"time"
@@ -13,7 +17,8 @@ import (
)
// maxClients is how many clients are kept. Past it, the least recently
// seen client is dropped, and starts afresh if it comes back.
// seen client is dropped, with its history, and starts afresh if it comes
// back.
const maxClients = 20000
const day = 24 * time.Hour
@@ -26,20 +31,99 @@ type Limits struct {
PerDay int64
}
// Limiter counts each client's requests against the limits. It is safe
// for concurrent use.
// Limiter counts each client's requests against the limits, and keeps
// its history. It is safe for concurrent use.
type Limiter struct {
// windows are the minute, the hour and the day, in the order of
// Client.buckets.
windows [3]window
mu sync.Mutex
// clients holds each client's buckets, one pair for each of windows,
// in the same order.
clients *simplelru.LRU[netip.Prefix, *[3]buckets]
mu sync.Mutex
clients *simplelru.LRU[netip.Prefix, *Client]
}
// Client is a client in the table, as clients.json holds it: its buckets
// in each window, and its history.
type Client struct {
Client netip.Prefix `json:"client"`
Minute Buckets `json:"minute"`
Hour Buckets `json:"hour"`
Day Buckets `json:"day"`
History History `json:"history"`
}
// Buckets are a client's two buckets in one window: the requests in the
// bucket under way, which began at Start, and in the bucket before it.
type Buckets struct {
Start time.Time `json:"start"`
Current int64 `json:"current"`
Previous int64 `json:"previous"`
}
// History is what is known of a client since it was first seen.
//
//nolint:tagliatelle // the state files use snake_case, as the request log does
type History struct {
FirstSeen time.Time `json:"first_seen"`
LastSeen time.Time `json:"last_seen"`
// Country is the client's country as it was last looked up, and
// LookedUp when that was; both are empty while it never was.
Country string `json:"country,omitempty"`
LookedUp time.Time `json:"looked_up,omitzero"`
// Requests are all the client's requests: Forwarded those passed to
// the app, Refused those refused before anything reached it, a 401 at
// smallwebwaf's own endpoints included, and neither the others
// smallwebwaf answered there.
Requests int64 `json:"requests"`
Forwarded int64 `json:"forwarded"`
Refused int64 `json:"refused"`
// RequestBytes and ResponseBytes are the body bytes of its requests
// and of the responses it was sent.
RequestBytes int64 `json:"request_bytes"`
ResponseBytes int64 `json:"response_bytes"`
Responses Responses `json:"responses,omitzero"`
Offences Offences `json:"offences,omitzero"`
}
// Responses are the responses a client was sent, by status class;
// Status5xx counts every status from 500 up.
type Responses struct {
Status1xx int64 `json:"1xx,omitempty"`
Status2xx int64 `json:"2xx,omitempty"`
Status3xx int64 `json:"3xx,omitempty"`
Status4xx int64 `json:"4xx,omitempty"`
Status5xx int64 `json:"5xx,omitempty"`
}
// Offences are a client's offences, by kind.
type Offences struct {
// Limit is its requests that broke a rate limit.
Limit int64 `json:"limit"`
}
// Request is what a client's history keeps of one of its requests.
type Request struct {
// Country is the client's country, when the request looked it up.
Country string
// Forwarded is true for a request passed to the app, Refused for one
// refused before anything reached it, a 401 at smallwebwaf's own
// endpoints included. Both are false for any other request smallwebwaf
// answered there.
Forwarded bool
Refused bool
// Status is what the client was sent, 0 if nothing was.
Status int
// RequestBytes and ResponseBytes are the body bytes of the request
// and of its response.
RequestBytes int64
ResponseBytes int64
// BrokeLimit is true for a request that broke a rate limit.
BrokeLimit bool
}
// New returns a Limiter for limits, with no client counted yet.
func New(limits Limits) *Limiter {
clients, err := simplelru.NewLRU[netip.Prefix, *[3]buckets](maxClients, nil)
clients, err := simplelru.NewLRU[netip.Prefix, *Client](maxClients, nil)
if err != nil {
panic(err) // NewLRU fails only for a size below one
}
@@ -54,30 +138,194 @@ func New(limits Limits) *Limiter {
}
}
// Hit is a request that takes a client over a rate limit.
type Hit struct {
// Window is "minute", "hour" or "day".
Window string
// Limit is the window's limit.
Limit int64
// Requests is the client's requests counted in the window, this one
// included.
Requests float64
}
// Counts are a client's requests in the minute, the hour and the day that
// end at a request, that request included.
type Counts struct {
Minute float64 `json:"minute"`
Hour float64 `json:"hour"`
Day float64 `json:"day"`
}
// Count counts a request from client at now, in every window, whether or
// not it is refused. It returns the window whose limit the request takes
// the client over, "minute", "hour" or "day", the shortest if it is over
// several, or "" if it is within every limit.
func (l *Limiter) Count(client netip.Prefix, now time.Time) string {
// not it is refused, and returns the client's requests in each window. It
// reports whether the request takes the client over a limit, and the
// window whose limit it goes over, the shortest if it is over several.
func (l *Limiter) Count(client netip.Prefix, now time.Time) (Counts, Hit, bool) {
l.mu.Lock()
defer l.mu.Unlock()
counts, seen := l.clients.Get(client)
if !seen {
counts = &[3]buckets{}
l.clients.Add(client, counts)
}
var (
requests [3]float64
hit Hit
)
limitHit := ""
for i, b := range l.get(client).buckets() {
w := l.windows[i]
for i, w := range l.windows {
requests := counts[i].add(now, w.length)
if limitHit == "" && w.limit > 0 && requests > float64(w.limit) {
limitHit = w.name
requests[i] = b.add(now, w.length)
if hit.Window == "" && w.limit > 0 && requests[i] > float64(w.limit) {
hit = Hit{Window: w.name, Limit: w.limit, Requests: requests[i]}
}
}
return limitHit
counts := Counts{Minute: requests[0], Hour: requests[1], Day: requests[2]}
return counts, hit, hit.Window != ""
}
// Reset sets client's counts in every window back to zero. Its history
// keeps its totals.
func (l *Limiter) Reset(client netip.Prefix) {
l.mu.Lock()
defer l.mu.Unlock()
c, seen := l.clients.Peek(client)
if seen {
c.Minute, c.Hour, c.Day = Buckets{}, Buckets{}, Buckets{}
}
}
// AddToHistory adds r, a request from client at now, to the client's
// history.
func (l *Limiter) AddToHistory(client netip.Prefix, now time.Time, r Request) {
l.mu.Lock()
defer l.mu.Unlock()
h := &l.get(client).History
if h.FirstSeen.IsZero() {
h.FirstSeen = now
}
h.LastSeen = now
if r.Country != "" {
h.Country = r.Country
h.LookedUp = now
}
h.Requests++
if r.Forwarded {
h.Forwarded++
}
if r.Refused {
h.Refused++
}
h.RequestBytes += r.RequestBytes
h.ResponseBytes += r.ResponseBytes
h.Responses.add(r.Status)
if r.BrokeLimit {
h.Offences.Limit++
}
}
// Requests returns how many requests the clients inside netblock have
// sent, as their histories count them.
func (l *Limiter) Requests(netblock netip.Prefix) int64 {
l.mu.Lock()
defer l.mu.Unlock()
// Most often the netblock is one client.
c, seen := l.clients.Peek(netblock)
if seen {
return c.History.Requests
}
var requests int64
for _, c := range l.clients.Values() {
if netblock.Overlaps(c.Client) {
requests += c.History.Requests
}
}
return requests
}
// Len returns how many clients are in the table.
func (l *Limiter) Len() int {
l.mu.Lock()
defer l.mu.Unlock()
return l.clients.Len()
}
// Snapshot returns every client in the table, sorted by address, as
// clients.json lists them.
func (l *Limiter) Snapshot() []Client {
l.mu.Lock()
clients := make([]Client, 0, l.clients.Len())
for _, c := range l.clients.Values() {
clients = append(clients, *c)
}
l.mu.Unlock()
slices.SortFunc(clients, func(a, b Client) int {
return a.Client.Compare(b.Client)
})
return clients
}
// Load puts clients read from clients.json into the table, in place of
// the clients it holds, in the order they were last seen, so that the
// least recently seen is dropped first. Buckets whose time has passed at
// now are emptied.
func (l *Limiter) Load(clients []Client, now time.Time) {
clients = slices.Clone(clients)
slices.SortStableFunc(clients, func(a, b Client) int {
return a.History.LastSeen.Compare(b.History.LastSeen)
})
l.mu.Lock()
defer l.mu.Unlock()
l.clients.Purge()
for _, c := range clients {
for i, b := range c.buckets() {
// The window that ends at now covers neither bucket once it
// begins after the bucket under way has ended.
length := l.windows[i].length
if !now.Add(-length).Before(b.Start.Add(length)) {
*b = Buckets{}
}
}
l.clients.Add(c.Client, &c)
}
}
// get returns client's entry in the table, a new one if it has none, and
// makes it the most recently seen.
func (l *Limiter) get(client netip.Prefix) *Client {
c, seen := l.clients.Get(client)
if !seen {
c = &Client{Client: client}
l.clients.Add(client, c)
}
return c
}
// buckets returns c's buckets in the minute, the hour and the day.
func (c *Client) buckets() [3]*Buckets {
return [3]*Buckets{&c.Minute, &c.Hour, &c.Day}
}
// window is a length of time over which requests are counted, and the
@@ -88,14 +336,6 @@ type window struct {
limit int64
}
// buckets are a client's two buckets in one window: the requests in the
// bucket under way, which began at start, and in the bucket before it.
type buckets struct {
start time.Time
current int64
previous int64
}
// add counts a request at now in a window of length, and returns the
// client's requests in the window that ends at now: those in the bucket
// under way, and those in the bucket before it weighted by how much of
@@ -106,27 +346,44 @@ type buckets struct {
// bucket. A request dated more than a second before it means the clock
// was set back, and the buckets start afresh: otherwise the bucket before
// would keep its full weight until the clock caught up.
func (b *buckets) add(now time.Time, length time.Duration) float64 {
if now.Before(b.start.Add(-time.Second)) {
*b = buckets{}
func (b *Buckets) add(now time.Time, length time.Duration) float64 {
if now.Before(b.Start.Add(-time.Second)) {
*b = Buckets{}
}
start := now.Truncate(length)
if start.After(b.start) {
if start.Equal(b.start.Add(length)) {
b.previous = b.current
if start.After(b.Start) {
if start.Equal(b.Start.Add(length)) {
b.Previous = b.Current
} else {
b.previous = 0
b.Previous = 0
}
b.start = start
b.current = 0
b.Start = start
b.Current = 0
}
b.current++
b.Current++
elapsed := max(now.Sub(b.start), 0)
elapsed := max(now.Sub(b.Start), 0)
covered := 1 - float64(elapsed)/float64(length)
return float64(b.previous)*covered + float64(b.current)
return float64(b.Previous)*covered + float64(b.Current)
}
// add counts a response with status in its class. A status of 0, for
// nothing sent, is not a response.
func (r *Responses) add(status int) {
switch {
case status >= http.StatusInternalServerError:
r.Status5xx++
case status >= http.StatusBadRequest:
r.Status4xx++
case status >= http.StatusMultipleChoices:
r.Status3xx++
case status >= http.StatusOK:
r.Status2xx++
case status >= http.StatusContinue:
r.Status1xx++
}
}
internal/ratelimit/ratelimit_test.go
+72 -3
View File
@@ -54,6 +54,75 @@ func TestEachWindowRefusesAtItsLimitAndLetsTheClientBack(t *testing.T) {
}
}
func TestHitGivesTheLimitAndTheRequestsCounted(t *testing.T) {
t.Parallel()
limiter := ratelimit.New(ratelimit.Limits{PerMinute: limit, PerHour: limit})
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
for range limit {
_, _, over := limiter.Count(client, start)
if over {
t.Fatal("a request within the limit is over it")
}
}
// Over both limits; the minute's is named, with the four requests.
_, hit, over := limiter.Count(client, start)
want := ratelimit.Hit{Window: minute, Limit: limit, Requests: limit + 1}
if !over || hit != want {
t.Errorf("request over the limit gives %+v and %t, want %+v and true",
hit, over, want)
}
}
func TestCountGivesTheRequestsInEachWindow(t *testing.T) {
t.Parallel()
limiter := ratelimit.New(ratelimit.Limits{})
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
for range 3 {
limiter.Count(client, start)
}
// A quarter into the next hour, the minute has only this request. The
// hour still covers three quarters of the bucket before, with its three
// requests, which count 2.25, and this one: 3.25. The day covers all
// four.
counts, _, _ := limiter.Count(client, start.Add(time.Hour+time.Hour/4))
want := ratelimit.Counts{Minute: 1, Hour: 3.25, Day: 4}
if counts != want {
t.Errorf("counts %+v, want %+v", counts, want)
}
}
func TestResetSetsTheCountsBackToZero(t *testing.T) {
t.Parallel()
limiter := ratelimit.New(ratelimit.Limits{PerMinute: limit, PerDay: limit})
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
for range limit {
wantCount(t, limiter, client, start, "")
}
wantCount(t, limiter, client, start, minute)
limiter.Reset(client)
// At the same moment, the client has its whole allowance again.
for range limit {
wantCount(t, limiter, client, start, "")
}
wantCount(t, limiter, client, start, minute)
}
func TestClientBackAfterAWholeBucketIsWithinTheLimitAtOnce(t *testing.T) {
t.Parallel()
@@ -192,9 +261,9 @@ func wantCount(
) {
t.Helper()
got := limiter.Count(client, now)
if got != want {
_, hit, _ := limiter.Count(client, now)
if hit.Window != want {
t.Errorf("request from %s at %s is over %q, want %q",
client, now.Format(time.RFC3339), got, want)
client, now.Format(time.RFC3339), hit.Window, want)
}
}
internal/ratelimit/snapshot_test.go
+122
View File
@@ -0,0 +1,122 @@
package ratelimit_test
import (
"net/netip"
"slices"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
)
func TestSnapshotListsTheClientsByAddress(t *testing.T) {
t.Parallel()
want := []string{"192.0.2.1/32", "203.0.113.9/32", "203.0.113.10/32", "2001:db8::/64"}
limiter := ratelimit.New(ratelimit.Limits{})
for _, i := range []int{2, 3, 0, 1} {
limiter.Count(netip.MustParsePrefix(want[i]), midnight())
}
snapshot := limiter.Snapshot()
got := make([]string, 0, len(snapshot))
for _, c := range snapshot {
got = append(got, c.Client.String())
}
if !slices.Equal(got, want) {
t.Errorf("snapshot %v, want %v", got, want)
}
counted := ratelimit.Buckets{Start: midnight(), Current: 1}
if snapshot[0].Minute != counted || snapshot[0].Day != counted {
t.Errorf("buckets %+v and %+v, want %+v", snapshot[0].Minute, snapshot[0].Day,
counted)
}
}
func TestLoadedCountsCarryOn(t *testing.T) {
t.Parallel()
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
before := ratelimit.New(ratelimit.Limits{PerHour: limit})
for range limit {
wantCount(t, before, client, start, "")
}
// Loaded into a new limiter, as across a restart, the client has no
// fresh allowance.
later := start.Add(time.Minute)
after := ratelimit.New(ratelimit.Limits{PerHour: limit})
after.Load(before.Snapshot(), later)
wantCount(t, after, client, later, hour)
}
func TestLoadEmptiesBucketsWhoseTimeHasPassed(t *testing.T) {
t.Parallel()
client := netip.MustParsePrefix("203.0.113.9/32")
start := midnight()
limiter := ratelimit.New(ratelimit.Limits{})
limiter.Count(client, start)
limiter.AddToHistory(client, start, ratelimit.Request{Forwarded: true})
loaded := func(now time.Time) ratelimit.Client {
t.Helper()
after := ratelimit.New(ratelimit.Limits{})
after.Load(limiter.Snapshot(), now)
return after.Snapshot()[0]
}
// Two minutes on, the window that ends then covers neither of the
// minute's buckets, which are emptied; the hour's and the day's stay,
// and so does the history.
got := loaded(start.Add(2 * time.Minute))
if got.Minute != (ratelimit.Buckets{}) || got.Hour.Current != 1 ||
got.Day.Current != 1 || got.History.Requests != 1 {
t.Errorf("loaded two minutes on as %+v", got)
}
// A moment before, the window still covers some of the earlier one.
got = loaded(start.Add(2*time.Minute - time.Nanosecond))
if got.Minute.Current != 1 {
t.Errorf("loaded just under two minutes on with minute buckets %+v",
got.Minute)
}
}
func TestLoadDropsTheLeastRecentlySeenFirst(t *testing.T) {
t.Parallel()
const maxClients = 20000
// clients.json lists the clients by address. Here each was last seen
// a second before the one listed before it, so the last listed is the
// one seen longest ago, and the one dropped.
clients := make([]ratelimit.Client, maxClients+1)
addr := netip.MustParseAddr("10.0.0.0")
for i := range clients {
clients[i].Client = netip.PrefixFrom(addr, addr.BitLen())
clients[i].History.LastSeen = midnight().Add(-time.Duration(i) * time.Second)
addr = addr.Next()
}
limiter := ratelimit.New(ratelimit.Limits{})
limiter.Load(clients, midnight())
got := limiter.Snapshot()
if len(got) != maxClients || got[0].Client != clients[0].Client ||
got[maxClients-1].Client != clients[maxClients-1].Client {
t.Errorf("%d clients kept, from %s to %s; want %d, from %s to %s",
len(got), got[0].Client, got[len(got)-1].Client, maxClients,
clients[0].Client, clients[maxClients-1].Client)
}
}
internal/requestlog/requestlog.go
+96 -24
View File
@@ -9,6 +9,8 @@ import (
"io"
"log/slog"
"time"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
)
// The action a request line names: what smallwebwaf did with the
@@ -24,42 +26,112 @@ const (
// for, or whose answer could not be passed on.
ActionUpstreamError = "upstream_error"
// ActionRateLimited is a request refused because it took its client
// over a rate limit, or came while the client was over one.
// over a rate limit, which bans the client.
ActionRateLimited = "rate_limited"
// ActionBanned is a request refused because a ban covers its client.
ActionBanned = "banned"
// ActionDenied is a request refused because its client is in
// SWWAF_DENY_NETS.
ActionDenied = "denied"
// ActionCountryDenied is a request refused for its client's country.
ActionCountryDenied = "country_denied"
// ActionAdmin is a request smallwebwaf answered at one of its own
// endpoints, under /_smallwebwaf/.
ActionAdmin = "admin"
)
// OffenceLimit is the offence a request line names for a request that
// broke a rate limit.
const OffenceLimit = "limit"
// timeLayout is RFC 3339 with milliseconds.
const timeLayout = "2006-01-02T15:04:05.000Z07:00"
// Line is one request's line in the request log. The field names are
// those of the "Request log" section of SPEC.md.
// Line is one request's line in the request log. The field names, and
// their order, are those of the "Request log" section of SPEC.md. A field
// that may not apply to a request is left out of its line when it does
// not.
//
//nolint:tagliatelle // SPEC.md's request log names its fields in snake_case
type Line struct {
Type string `json:"type"`
Time string `json:"time"`
ClientIP string `json:"client_ip"`
PeerIP string `json:"peer_ip"`
Method string `json:"method"`
Host string `json:"host"`
Path string `json:"path"`
Query string `json:"query"`
Protocol string `json:"protocol"`
Status int `json:"status"`
UpstreamStatus int `json:"upstream_status,omitempty"`
RequestBytes int64 `json:"request_bytes"`
ResponseBytes int64 `json:"response_bytes"`
Referer string `json:"referer"`
UserAgent string `json:"user_agent"`
Action string `json:"action"`
Type string `json:"type"`
// The standard web log fields. Scheme is how the client reached
// smallwebwaf, or the trusted proxy in front of it.
Time string `json:"time"`
Instance string `json:"instance"`
ClientIP string `json:"client_ip"`
Method string `json:"method"`
Scheme string `json:"scheme"`
Host string `json:"host"`
Path string `json:"path"`
Query string `json:"query"`
Protocol string `json:"protocol"`
Status int `json:"status"`
RequestBytes int64 `json:"request_bytes"`
ResponseBytes int64 `json:"response_bytes"`
Referer string `json:"referer"`
UserAgent string `json:"user_agent"`
// Request detail. RequestID is the X-Request-ID a trusted proxy sent,
// or a new one, and is sent on to the app. ForwardedFor is the
// X-Forwarded-For header as received. ClientGroup is the netblock the
// client is counted as.
RequestID string `json:"request_id"`
PeerIP string `json:"peer_ip"`
ForwardedFor string `json:"forwarded_for,omitempty"`
ClientGroup string `json:"client_group"`
Country string `json:"country"`
ContentType string `json:"content_type,omitempty"`
// ContentLength is the length of its body the request announced.
ContentLength int64 `json:"content_length,omitempty"`
// RequestHeaders are the headers SWWAF_LOG_REQUEST_HEADERS names that
// the request carried, by name in lower case.
RequestHeaders map[string]string `json:"request_headers,omitempty"`
HasAuthorization bool `json:"has_authorization,omitempty"`
HasCookie bool `json:"has_cookie,omitempty"`
// Websocket is true when the connection was upgraded, as for a
// WebSocket.
Websocket bool `json:"websocket,omitempty"`
// Response detail, from the headers of the answer: the app's, as
// passed on, or those of smallwebwaf's own. Aborted is true when the
// client went away early.
ResponseContentType string `json:"response_content_type,omitempty"`
UpstreamStatus int `json:"upstream_status,omitempty"`
CacheControl string `json:"cache_control,omitempty"`
Location string `json:"location,omitempty"`
Aborted bool `json:"aborted,omitempty"`
// The decision.
Action string `json:"action"`
// WouldAction is, in observe mode, the action enforce mode would have
// taken with a request it would have refused: ActionDenied,
// ActionBanned, ActionCountryDenied or ActionRateLimited.
WouldAction string `json:"would_action,omitempty"`
// Counts are the client's requests as the rate limits counted them
// with this one, for a request they counted.
Counts ratelimit.Counts `json:"counts,omitzero"`
// LimitHit is the window whose rate limit the request went over:
// minute, hour or day.
LimitHit string `json:"limit_hit,omitempty"`
// Aborted is true when the client went away early.
Aborted bool `json:"aborted,omitempty"`
// DurationTotal and DurationUpstreamTotal are in milliseconds.
DurationTotal float64 `json:"duration_total"`
DurationUpstreamTotal float64 `json:"duration_upstream_total,omitempty"`
// Offence is the offence the request was held as, OffenceLimit.
Offence string `json:"offence,omitempty"`
// BanExpires is when the ban the request made, or was refused under,
// ends: a time, or "permanent".
BanExpires string `json:"ban_expires,omitempty"`
// The timings, in milliseconds. DurationChecks is the time until the
// checks were done. DurationUpstreamConnect, DurationUpstreamFirstByte
// and DurationUpstreamTotal run from when the request was handed to the
// app: until there was a connection to it, until the first byte of its
// answer arrived, and until the end. Each but DurationTotal is nil for
// a request that did not get that far.
DurationTotal float64 `json:"duration_total"`
DurationChecks *float64 `json:"duration_checks,omitempty"`
DurationUpstreamConnect *float64 `json:"duration_upstream_connect,omitempty"`
DurationUpstreamFirstByte *float64 `json:"duration_upstream_first_byte,omitempty"`
DurationUpstreamTotal *float64 `json:"duration_upstream_total,omitempty"`
}
// Write writes line to w as one JSON line marked "type":"request".
internal/requestlog/requestlog_test.go
+6 -1
View File
@@ -50,7 +50,12 @@ func TestWriteWritesOneJSONLineMarkedRequest(t *testing.T) {
}
unset := []string{
"upstream_status", "limit_hit", "aborted", "duration_upstream_total",
"forwarded_for", "content_type", "content_length", "request_headers",
"has_authorization", "has_cookie", "websocket", "response_content_type",
"upstream_status", "cache_control", "location", "aborted", "counts",
"limit_hit", "offence", "ban_expires", "duration_checks",
"duration_upstream_connect", "duration_upstream_first_byte",
"duration_upstream_total",
}
for _, name := range unset {
_, present := fields[name]
internal/smallwebwaf/healthcheck.go
+100
View File
@@ -0,0 +1,100 @@
package smallwebwaf
import (
"context"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/url"
"time"
"sneak.berlin/go/smallwebwaf/internal/config"
"sneak.berlin/go/smallwebwaf/internal/proxy"
)
// healthCheckTimeout bounds the whole health check.
const healthCheckTimeout = 5 * time.Second
var errHealthEndpoint = errors.New("smallwebwaf's health endpoint answered")
// HealthCheck is the container's health check. It returns 0 while
// smallwebwaf answers its health endpoint on 127.0.0.1, at the port in
// SWWAF_LISTEN_ADDR, and the app accepts connections at the address in
// SWWAF_UPSTREAM_URL. Otherwise it writes why to stderr and returns 1.
// args are the arguments after `healthcheck`; it takes none, and given
// one it names it on stderr and returns 1 without checking anything.
func HealthCheck(
ctx context.Context, args []string, lookupEnv func(string) (string, bool),
stderr io.Writer,
) int {
if len(args) > 0 {
_, _ = fmt.Fprintf(stderr,
"smallwebwaf healthcheck: unexpected argument %q\n", args[0])
return 1
}
err := healthCheck(ctx, lookupEnv)
if err != nil {
_, _ = fmt.Fprintln(stderr, "unhealthy:", err)
return 1
}
return 0
}
func healthCheck(ctx context.Context, lookupEnv func(string) (string, bool)) error {
ctx, cancel := context.WithTimeout(ctx, healthCheckTimeout)
defer cancel()
cfg, err := config.FromEnvironment(lookupEnv)
if err != nil {
return fmt.Errorf("invalid setting: %w", err)
}
// The settings have checked that the address has a port.
_, port, _ := net.SplitHostPort(cfg.ListenAddr)
health := "http://" + net.JoinHostPort("127.0.0.1", port) + proxy.HealthPath
req, err := http.NewRequestWithContext(ctx, http.MethodGet, health, http.NoBody)
if err != nil {
return fmt.Errorf("make the request: %w", err)
}
res, err := http.DefaultClient.Do(req)
if err != nil {
return fmt.Errorf("ask smallwebwaf: %w", err)
}
_ = res.Body.Close()
if res.StatusCode != http.StatusOK {
return fmt.Errorf("%w %s", errHealthEndpoint, res.Status)
}
conn, err := (&net.Dialer{}).DialContext(ctx, "tcp", appAddress(cfg.UpstreamURL))
if err != nil {
return fmt.Errorf("connect to the app: %w", err)
}
_ = conn.Close()
return nil
}
// appAddress is the host and port of the app's URL, the port being the
// scheme's own when the URL names none.
func appAddress(app *url.URL) string {
port := app.Port()
if port == "" {
port = "80"
if app.Scheme == "https" {
port = "443"
}
}
return net.JoinHostPort(app.Hostname(), port)
}
internal/smallwebwaf/healthcheck_internal_test.go
+27
View File
@@ -0,0 +1,27 @@
package smallwebwaf
import (
"net/url"
"testing"
)
func TestAppAddress(t *testing.T) {
t.Parallel()
for app, want := range map[string]string{
"http://127.0.0.1:8081": "127.0.0.1:8081",
"http://app": "app:80",
"https://app/": "app:443",
"https://[::1]": "[::1]:443",
} {
parsed, err := url.Parse(app)
if err != nil {
t.Fatalf("parse %q: %v", app, err)
}
got := appAddress(parsed)
if got != want {
t.Errorf("appAddress(%q) is %q, want %q", app, got, want)
}
}
}
internal/smallwebwaf/healthcheck_test.go
+99
View File
@@ -0,0 +1,99 @@
package smallwebwaf_test
import (
"bytes"
"context"
"net"
"net/http"
"net/http/httptest"
"strings"
"testing"
"time"
"sneak.berlin/go/smallwebwaf/internal/smallwebwaf"
)
func TestHealthCheck(t *testing.T) {
t.Parallel()
app := httptest.NewServer(http.NotFoundHandler())
defer app.Close()
ctx, stop := context.WithCancel(t.Context())
defer stop()
out := &output{}
exited := make(chan int, 1)
settings := map[string]string{
listenAddr: localhost + ":0",
upstreamURL: app.URL,
stateDir: t.TempDir(),
}
go func() {
exited <- run(ctx, settings, out)
}()
addr, _ := out.line(t, "msg", "starting")["address"].(string)
_, port, _ := net.SplitHostPort(addr)
// The container's settings: an address to listen on with an empty
// host part, which the health check asks at 127.0.0.1.
env := map[string]string{listenAddr: ":" + port, upstreamURL: app.URL}
wantHealthCheck(t, env, 0, "")
app.Close()
wantHealthCheck(t, env, 1, "unhealthy: connect to the app: ")
stop()
select {
case <-exited:
case <-time.After(waitLimit):
t.Fatal("still running after being told to stop")
}
wantHealthCheck(t, env, 1, "unhealthy: ask smallwebwaf: ")
wantHealthCheck(t, map[string]string{listenAddr: "8080"}, 1,
"unhealthy: invalid setting: SWWAF_LISTEN_ADDR: ")
}
func TestHealthCheckRefusesAnArgument(t *testing.T) {
t.Parallel()
var stderr bytes.Buffer
noSettings := func(string) (string, bool) {
return "", false
}
got := smallwebwaf.HealthCheck(t.Context(), []string{"now"}, noSettings, &stderr)
want := "smallwebwaf healthcheck: unexpected argument \"now\"\n"
if got != 1 || stderr.String() != want {
t.Errorf("health check returned %d and wrote %q, want 1 and %q",
got, stderr.String(), want)
}
}
// wantHealthCheck runs the health check with the settings in env, and
// checks its exit status and the start of what it writes to stderr,
// which is nothing when message is empty.
func wantHealthCheck(t *testing.T, env map[string]string, status int, message string) {
t.Helper()
var stderr bytes.Buffer
got := smallwebwaf.HealthCheck(t.Context(), nil, func(name string) (string, bool) {
value, ok := env[name]
return value, ok
}, &stderr)
wrote := stderr.String()
if got != status || !strings.HasPrefix(wrote, message) ||
(message == "" && wrote != "") {
t.Errorf("health check returned %d and wrote %q, want %d and %q",
got, wrote, status, message)
}
}
internal/smallwebwaf/smallwebwaf.go
+81 -16
View File
@@ -1,6 +1,6 @@
// Package smallwebwaf runs the smallwebwaf process: it reads the settings,
// serves requests until it is told to stop, and then stops in an orderly
// way.
// Package smallwebwaf runs the smallwebwaf process: it reads the settings
// and the state files, serves requests until it is told to stop, and then
// stops in an orderly way, writing the state files.
package smallwebwaf
import (
@@ -16,8 +16,10 @@ import (
"time"
"sneak.berlin/go/smallwebwaf/internal/config"
"sneak.berlin/go/smallwebwaf/internal/lookup"
"sneak.berlin/go/smallwebwaf/internal/proxy"
"sneak.berlin/go/smallwebwaf/internal/requestlog"
"sneak.berlin/go/smallwebwaf/internal/state"
)
// shutdownTimeout is how long requests in progress may take to finish
@@ -36,8 +38,13 @@ type Params struct {
}
// Main runs smallwebwaf until SIGTERM or SIGINT, and returns the
// process's exit status.
// process's exit status. Run as `smallwebwaf healthcheck`, it is the
// container's health check instead.
func Main(version string) int {
if len(os.Args) > 1 && os.Args[1] == "healthcheck" {
return HealthCheck(context.Background(), os.Args[2:], os.LookupEnv, os.Stderr)
}
ctx, stop := signal.NotifyContext(context.Background(),
syscall.SIGTERM, os.Interrupt)
defer stop()
@@ -49,8 +56,9 @@ func Main(version string) int {
})
}
// Run reads the settings, then serves requests until ctx is done. It
// returns the process's exit status, 1 when smallwebwaf cannot start.
// Run reads the settings and the state files, then serves requests until
// ctx is done. It returns the process's exit status, 1 when smallwebwaf
// cannot start.
func Run(ctx context.Context, params Params) int {
processLog := requestlog.NewProcessLogger(params.Stdout)
@@ -61,6 +69,34 @@ func Run(ctx context.Context, params Params) int {
return 1
}
// The state files give times in UTC.
now := func() time.Time { return time.Now().UTC() }
server := proxy.New(proxy.Params{
Config: cfg,
RequestLog: params.Stdout,
ProcessLog: processLog,
GeoJSURL: lookup.URL,
Now: now,
})
files, err := state.Load(state.Params{
Dir: cfg.StateDir,
WriteDelay: cfg.StateWriteDelay,
CounterInterval: cfg.StateCounterInterval,
Ledger: server.Ledger,
Limiter: server.Limiter,
GeoJS: server.GeoJS,
Now: now,
ProcessLog: processLog,
Metrics: server.Metrics,
})
if err != nil {
processLog.Error("cannot use the state files", "error", err.Error())
return 1
}
listener, err := (&net.ListenConfig{}).Listen(ctx, "tcp", cfg.ListenAddr)
if err != nil {
processLog.Error("cannot listen on SWWAF_LISTEN_ADDR",
@@ -69,25 +105,21 @@ func Run(ctx context.Context, params Params) int {
return 1
}
server := proxy.New(proxy.Params{
Config: cfg,
RequestLog: params.Stdout,
ProcessLog: processLog,
})
processLog.Info("starting",
"version", params.Version,
"address", listener.Addr().String(),
"settings", cfg)
return serve(ctx, server, listener, processLog)
return serve(ctx, server.Server, listener, files, processLog)
}
// serve serves requests on listener until ctx is done, then gives the
// requests in progress shutdownTimeout to finish.
// serve serves requests on listener, writes the state files as they are
// due, and takes in an admin's edits of them, until ctx is done. Then it
// gives the requests in progress shutdownTimeout to finish, and writes
// every state file.
func serve(
ctx context.Context, server *http.Server, listener net.Listener,
processLog *slog.Logger,
files *state.Files, processLog *slog.Logger,
) int {
served := make(chan error, 1)
@@ -95,6 +127,22 @@ func serve(
served <- server.Serve(listener)
}()
writing, stopWriting := context.WithCancel(ctx)
defer stopWriting()
written := make(chan struct{})
watched := make(chan struct{})
go func() {
files.Run(writing)
close(written)
}()
go func() {
files.Watch(writing)
close(watched)
}()
select {
case err := <-served:
processLog.Error("serving failed", "error", err.Error())
@@ -124,6 +172,23 @@ func serve(
return 1
}
// Run and Watch have ended, so nothing else reads or writes the
// files. Every request has ended too, but for two kinds
// that Go's server does not wait for: one cut off because Shutdown
// timed out, and one whose connection switched protocols, such as a
// WebSocket. Such a request adds to its client's history only as it
// ends, which can be after this write, and then that request is
// missing from clients.json.
<-written
<-watched
err = files.WriteAll()
if err != nil {
processLog.Error("writing the state files failed", "error", err.Error())
return 1
}
processLog.Info("stopped")
return 0
internal/smallwebwaf/smallwebwaf_test.go
+369 -26
View File
@@ -8,6 +8,8 @@ import (
"net"
"net/http"
"net/http/httptest"
"os"
"path/filepath"
"strings"
"sync"
"testing"
@@ -24,8 +26,16 @@ const (
// testVersion is the version the tests give smallwebwaf.
testVersion = "test"
// localhost is where the tests listen.
localhost = "127.0.0.1"
listenAddr = "SWWAF_LISTEN_ADDR"
localhost = "127.0.0.1"
listenAddr = "SWWAF_LISTEN_ADDR"
upstreamURL = "SWWAF_UPSTREAM_URL"
trustedProxies = "SWWAF_TRUSTED_PROXIES"
stateDir = "SWWAF_STATE_DIR"
stateWriteDelay = "SWWAF_STATE_WRITE_DELAY"
stateCounterInterval = "SWWAF_STATE_COUNTER_INTERVAL"
rateLimitPerDay = "SWWAF_RATE_LIMIT_PER_DAY"
// greeting is what the tests' app answers.
greeting = "hello from the app"
)
// output collects what smallwebwaf writes on stdout.
@@ -68,11 +78,19 @@ func (o *output) line(t *testing.T, key, value string) map[string]any {
time.Sleep(pollInterval)
}
t.Fatalf("no line with %s %q in the output:\n%s", key, value, o.buf.String())
t.Fatalf("no line with %s %q in the output:\n%s", key, value, o.text())
return nil
}
// text returns everything written so far.
func (o *output) text() string {
o.mu.Lock()
defer o.mu.Unlock()
return o.buf.String()
}
// run runs smallwebwaf with the settings in env until ctx is done, and
// returns its exit status.
func run(ctx context.Context, env map[string]string, out *output) int {
@@ -106,6 +124,28 @@ func TestInvalidSettingStopsTheStart(t *testing.T) {
}
}
func TestShortMetricsTokenStopsTheStartUnshown(t *testing.T) {
t.Parallel()
const token = "a-token-of-31-characters-at-all" //nolint:gosec // too short to use
out := &output{}
status := run(t.Context(), map[string]string{"SWWAF_METRICS_TOKEN": token}, out)
if status != 1 {
t.Errorf("exit status %d, want 1", status)
}
line := out.line(t, "msg", "invalid setting")
if line["error"] != "SWWAF_METRICS_TOKEN: is shorter than 32 characters" {
t.Errorf("start refused with %v", line)
}
if strings.Contains(out.text(), token) {
t.Errorf("the output shows the token:\n%s", out.text())
}
}
func TestAddressInUseStopsTheStart(t *testing.T) {
t.Parallel()
@@ -120,7 +160,10 @@ func TestAddressInUseStopsTheStart(t *testing.T) {
out := &output{}
status := run(t.Context(), map[string]string{listenAddr: taken.Addr().String()}, out)
status := run(t.Context(), map[string]string{
listenAddr: taken.Addr().String(),
stateDir: t.TempDir(),
}, out)
if status != 1 {
t.Errorf("exit status %d, want 1", status)
}
@@ -131,11 +174,8 @@ func TestAddressInUseStopsTheStart(t *testing.T) {
func TestServesUntilToldToStop(t *testing.T) {
t.Parallel()
app := httptest.NewServer(http.HandlerFunc(
func(w http.ResponseWriter, _ *http.Request) {
_, _ = io.WriteString(w, "hello from the app")
}))
defer app.Close()
appURL := startApp(t)
dir := t.TempDir()
ctx, stop := context.WithCancel(t.Context())
out := &output{}
@@ -143,13 +183,14 @@ func TestServesUntilToldToStop(t *testing.T) {
go func() {
exited <- run(ctx, map[string]string{
listenAddr: localhost + ":0",
"SWWAF_UPSTREAM_URL": app.URL,
listenAddr: localhost + ":0",
upstreamURL: appURL,
stateDir: dir,
}, out)
}()
starting := out.line(t, "msg", "starting")
wantStartingLine(t, starting, app.URL)
wantStartingLine(t, starting, appURL, dir)
addr, _ := starting["address"].(string)
wantGreeting(t, "http://"+addr+"/")
@@ -169,25 +210,241 @@ func TestServesUntilToldToStop(t *testing.T) {
out.line(t, "msg", "stopped")
}
func TestStateKeptAcrossRestarts(t *testing.T) {
t.Parallel()
env := map[string]string{
listenAddr: localhost + ":0",
upstreamURL: startApp(t),
stateDir: t.TempDir(),
rateLimitPerDay: "2",
// Neither comes due in the test: the files are written as
// smallwebwaf stops.
stateWriteDelay: "1h",
stateCounterInterval: "1h",
}
// The two requests a day allows, and a stop.
runUntilStopped(t, env, func(url string) {
wantGreeting(t, url)
wantGreeting(t, url)
})
// After a restart the client has no fresh allowance: its third
// request breaks the day limit, and bans it.
out := runUntilStopped(t, env, func(url string) {
wantRefused(t, url)
})
out.line(t, "action", "rate_limited")
// After another, the ban still refuses it.
out = runUntilStopped(t, env, func(url string) {
wantRefused(t, url)
})
out.line(t, "action", "banned")
}
func TestBanRefusesItsNetblockAfterARestartWithAnotherScope(t *testing.T) {
t.Parallel()
const scope = "SWWAF_BAN_SCOPE_V4_PREFIX"
env := map[string]string{
listenAddr: localhost + ":0",
upstreamURL: startApp(t),
stateDir: t.TempDir(),
trustedProxies: localhost + "/32",
rateLimitPerDay: "1",
scope: "24",
}
// 203.0.113.9's second request breaks the day limit, and bans
// 203.0.113.0/24.
runUntilStopped(t, env, func(url string) {
wantStatus(t, url, "203.0.113.9", http.StatusOK)
wantStatus(t, url, "203.0.113.9", http.StatusForbidden)
})
// With each address a netblock of its own after a restart, that ban
// still refuses all of 203.0.113.0/24. 198.51.100.7 is banned alone.
env[scope] = "32"
runUntilStopped(t, env, func(url string) {
wantStatus(t, url, "203.0.113.200", http.StatusForbidden)
wantStatus(t, url, "203.0.114.1", http.StatusOK)
wantStatus(t, url, "198.51.100.7", http.StatusOK)
wantStatus(t, url, "198.51.100.7", http.StatusForbidden)
})
// With /24 netblocks again, that ban still refuses 198.51.100.7, and
// no other address.
env[scope] = "24"
runUntilStopped(t, env, func(url string) {
wantStatus(t, url, "198.51.100.7", http.StatusForbidden)
wantStatus(t, url, "198.51.100.8", http.StatusOK)
})
}
func TestBanAddedAndLiftedByEditingBansJSON(t *testing.T) {
t.Parallel()
const (
// bans.json as an admin writes it with a ban, permanent, on
// 203.0.113.0/24, and with none.
oneBan = `{"version": 1, "bans": [{"netblock": "203.0.113.0/24", ` +
`"start": "2026-10-06T00:00:00Z", "expires": null}]}`
noBan = `{"version": 1, "bans": []}`
)
dir := t.TempDir()
env := map[string]string{
listenAddr: localhost + ":0",
upstreamURL: startApp(t),
stateDir: dir,
trustedProxies: localhost + "/32",
// No write comes due in the test, so only the watch on the
// directory can take the edits in.
stateWriteDelay: "1h",
stateCounterInterval: "1h",
}
runUntilStopped(t, env, func(url string) {
path := filepath.Join(dir, "bans.json")
saveUntilAnswered(t, path, oneBan, url, "203.0.113.9", http.StatusForbidden)
wantStatus(t, url, "198.51.100.7", http.StatusOK)
saveUntilAnswered(t, path, noBan, url, "203.0.113.9", http.StatusOK)
})
}
func TestStateFileThatDoesNotParseStopsTheStart(t *testing.T) {
t.Parallel()
dir := t.TempDir()
err := os.WriteFile(filepath.Join(dir, "bans.json"), []byte("{\n"), 0o600)
if err != nil {
t.Fatalf("write bans.json: %v", err)
}
// The file ends at the newline that is the second byte of its first
// line.
wantStartRefused(t, dir, filepath.Join(dir, "bans.json")+", line 1, column 2: ")
}
func TestUnwritableStateDirStopsTheStart(t *testing.T) {
t.Parallel()
wantStartRefused(t, filepath.Join(t.TempDir(), "missing"),
"SWWAF_STATE_DIR cannot be written: ")
}
// wantStartRefused runs smallwebwaf with its state files in dir, and
// checks that it stops at start, with an error that starts with want. If
// it starts instead, it is stopped after waitLimit.
func wantStartRefused(t *testing.T, dir, want string) {
t.Helper()
ctx, stop := context.WithTimeout(t.Context(), waitLimit)
defer stop()
out := &output{}
status := run(ctx, map[string]string{listenAddr: localhost + ":0", stateDir: dir}, out)
if status != 1 {
t.Fatalf("exit status %d, want 1", status)
}
line := out.line(t, "msg", "cannot use the state files")
message, _ := line["error"].(string)
if !strings.HasPrefix(message, want) {
t.Errorf("start refused with %q, want an error starting %q", message, want)
}
}
// startApp starts an app that answers every request with greeting, and
// returns its URL.
func startApp(t *testing.T) string {
t.Helper()
app := httptest.NewServer(http.HandlerFunc(
func(w http.ResponseWriter, _ *http.Request) {
_, _ = io.WriteString(w, greeting)
}))
t.Cleanup(app.Close)
return app.URL
}
// runUntilStopped runs smallwebwaf with the settings in env, has use send
// it requests at url, then stops it as SIGTERM does, checks that it
// stopped in order, and returns its output.
func runUntilStopped(
t *testing.T, env map[string]string, use func(url string),
) *output {
t.Helper()
ctx, stop := context.WithCancel(t.Context())
out := &output{}
exited := make(chan int, 1)
go func() {
exited <- run(ctx, env, out)
}()
addr, _ := out.line(t, "msg", "starting")["address"].(string)
use("http://" + addr + "/")
stop()
select {
case status := <-exited:
if status != 0 {
t.Fatalf("exit status %d, want 0; output:\n%s", status, out.text())
}
case <-time.After(waitLimit):
t.Fatal("still running after being told to stop")
}
return out
}
// wantStartingLine checks that the line at start gives the version and
// every setting's value.
func wantStartingLine(t *testing.T, line map[string]any, appURL string) {
func wantStartingLine(t *testing.T, line map[string]any, appURL, dir string) {
t.Helper()
settings, _ := line["settings"].(map[string]any)
want := map[string]any{
listenAddr: localhost + ":0",
"SWWAF_UPSTREAM_URL": appURL,
"SWWAF_TRUSTED_PROXIES": "10.0.0.0/8,172.16.0.0/12,192.168.0.0/16",
"SWWAF_CLIENT_REQUEST_TIMEOUT": "60s",
"SWWAF_CLIENT_RESPONSE_TIMEOUT": "30m",
"SWWAF_UPSTREAM_REQUEST_TIMEOUT": "60s",
"SWWAF_UPSTREAM_RESPONSE_TIMEOUT": "30m",
"SWWAF_REQUEST_MAX_BYTES": "100M",
"SWWAF_RESPONSE_MAX_BYTES": "5G",
"SWWAF_RATE_LIMIT_PER_MINUTE": "1000",
"SWWAF_RATE_LIMIT_PER_HOUR": "10000",
"SWWAF_RATE_LIMIT_PER_DAY": "50000",
listenAddr: localhost + ":0",
upstreamURL: appURL,
stateDir: dir,
"SWWAF_MODE": "enforce",
stateWriteDelay: "10s",
stateCounterInterval: "15m",
trustedProxies: "10.0.0.0/8,172.16.0.0/12,192.168.0.0/16",
"SWWAF_CLIENT_REQUEST_TIMEOUT": "60s",
"SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES": "32K",
"SWWAF_CLIENT_IDLE_TIMEOUT": "120s",
"SWWAF_CLIENT_RESPONSE_TIMEOUT": "30m",
"SWWAF_UPSTREAM_REQUEST_TIMEOUT": "60s",
"SWWAF_UPSTREAM_RESPONSE_TIMEOUT": "30m",
"SWWAF_REQUEST_MAX_BYTES": "100M",
"SWWAF_RESPONSE_MAX_BYTES": "5G",
"SWWAF_ALLOW_NETS": "",
"SWWAF_RATE_LIMIT_EXEMPT_NETS": "",
"SWWAF_DENY_NETS": "",
"SWWAF_RATE_LIMIT_PER_MINUTE": "1000",
"SWWAF_RATE_LIMIT_PER_HOUR": "10000",
rateLimitPerDay: "50000",
"SWWAF_RATE_LIMIT_EXEMPT_PATHS": "",
"SWWAF_DENIED_COUNTRIES": "",
"SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES": "",
"SWWAF_BAN_RESPONSE": "403",
"SWWAF_LIMIT_BAN_DURATION": "1h",
"SWWAF_LIMIT_BAN_REPEAT_WINDOW": "24h",
"SWWAF_MAX_BAN_DURATION": "7d",
"SWWAF_MAX_BANS": "5000",
"SWWAF_BAN_SCOPE_V4_PREFIX": "32",
}
for name, value := range want {
@@ -222,7 +479,93 @@ func wantGreeting(t *testing.T, url string) {
body, err := io.ReadAll(res.Body)
_ = res.Body.Close()
if err != nil || string(body) != "hello from the app" {
if err != nil || string(body) != greeting {
t.Errorf("got %q (%v), want the app's answer", body, err)
}
}
// wantRefused checks that a request to url is refused with 403, the
// default SWWAF_BAN_RESPONSE.
func wantRefused(t *testing.T, url string) {
t.Helper()
req, err := http.NewRequestWithContext(t.Context(), http.MethodGet, url,
http.NoBody)
if err != nil {
t.Fatalf("new request: %v", err)
}
transport := &http.Transport{}
defer transport.CloseIdleConnections()
res, err := (&http.Client{Transport: transport}).Do(req)
if err != nil {
t.Fatalf("request: %v", err)
}
_ = res.Body.Close()
if res.StatusCode != http.StatusForbidden {
t.Errorf("status %d, want %d", res.StatusCode, http.StatusForbidden)
}
}
// wantStatus checks that a request to url from the client at from, as
// X-Forwarded-For names it, is answered with status.
func wantStatus(t *testing.T, url, from string, status int) {
t.Helper()
got := statusFrom(t, url, from)
if got != status {
t.Errorf("request from %s: status %d, want %d", from, got, status)
}
}
// saveUntilAnswered writes content to the state file at path, as an
// admin saves an edit of it, until a request to url from the client at
// from is answered with status. The file is written again before each
// request, since smallwebwaf may not watch its directory yet when it is
// first written. It waits as long as that takes, so that a slow test
// process cannot fail the test.
func saveUntilAnswered(t *testing.T, path, content, url, from string, status int) {
t.Helper()
for {
err := os.WriteFile(path, []byte(content), 0o600)
if err != nil {
t.Fatalf("write %s: %v", path, err)
}
if statusFrom(t, url, from) == status {
return
}
time.Sleep(pollInterval)
}
}
// statusFrom returns the status a request to url from the client at
// from, as X-Forwarded-For names it, is answered with.
func statusFrom(t *testing.T, url, from string) int {
t.Helper()
req, err := http.NewRequestWithContext(t.Context(), http.MethodGet, url,
http.NoBody)
if err != nil {
t.Fatalf("new request: %v", err)
}
req.Header.Set("X-Forwarded-For", from)
transport := &http.Transport{}
defer transport.CloseIdleConnections()
res, err := (&http.Client{Transport: transport}).Do(req)
if err != nil {
t.Fatalf("request: %v", err)
}
_ = res.Body.Close()
return res.StatusCode
}
internal/state/state.go
+698
View File
@@ -0,0 +1,698 @@
// Package state keeps smallwebwaf's state in JSON files in
// SWWAF_STATE_DIR, as the "Persistent state" section of SPEC.md describes:
// bans.json holds the bans, clients.json each client's counters and
// history, and lookups.json GeoJS's answers. Load reads them at start,
// Watch takes in an admin's edit of one while smallwebwaf runs, and Run
// and WriteAll write them. The disk is read and written outside the
// parts' locks, which are held only to take a snapshot or to put in what
// a file holds, so that no request waits on the disk.
package state
import (
"bytes"
"context"
"crypto/sha256"
"encoding/json"
"errors"
"fmt"
"io/fs"
"log/slog"
"net/netip"
"os"
"path/filepath"
"sync"
"time"
"github.com/fsnotify/fsnotify"
"sneak.berlin/go/smallwebwaf/internal/bans"
"sneak.berlin/go/smallwebwaf/internal/lookup"
"sneak.berlin/go/smallwebwaf/internal/metrics"
"sneak.berlin/go/smallwebwaf/internal/ratelimit"
)
// version is the version of the files' format, the only one read.
const version = 1
// fileMode lets the smallwebwaf user alone read and write the files, which
// hold visitors' addresses.
const fileMode = 0o600
// The state files' names.
const (
bansJSON = "bans.json"
clientsJSON = "clients.json"
lookupsJSON = "lookups.json"
)
var (
errVersion = errors.New("unknown version")
// errMissing is for an entry without a field it needs.
errMissing = errors.New("has no")
)
// Params are what Load needs.
type Params struct {
// Dir is the directory of the state files (SWWAF_STATE_DIR).
Dir string
// WriteDelay is how long after a ban is made bans.json is written
// (SWWAF_STATE_WRITE_DELAY), and CounterInterval how often every file
// is (SWWAF_STATE_COUNTER_INTERVAL).
WriteDelay time.Duration
CounterInterval time.Duration
// Ledger, Limiter and GeoJS hold the state.
Ledger *bans.Ledger
Limiter *ratelimit.Limiter
GeoJS *lookup.GeoJS
// Now tells the time by which the counters' buckets run out, normally
// time.Now in UTC.
Now func() time.Time
// ProcessLog receives what was read and taken in, the edits set aside,
// and the writes that fail.
ProcessLog *slog.Logger
// Metrics count each file's writes, and the edits taken in and set
// aside.
Metrics *metrics.Metrics
}
// Files are the state files of a running smallwebwaf.
type Files struct {
params Params
// mu is held while a file is read for an edit, and while it is
// written, so that Watch and the writes take turns. No request takes
// it.
mu sync.Mutex
// sums are the SHA-256 sums of what each file held, by name, when
// smallwebwaf last read or wrote it. A file that holds anything else
// has been edited since.
sums map[string][sha256.Size]byte
}
// bansFile is bans.json, indented for an admin to read and edit.
type bansFile struct {
Version int `json:"version"`
Bans []banEntry `json:"bans"`
}
// banEntry is a ban as bans.json holds it: a permanent ban's expires is
// null.
type banEntry struct {
Netblock netip.Prefix `json:"netblock"`
Start time.Time `json:"start"`
Expires *time.Time `json:"expires"`
Notes bans.Notes `json:"notes"`
}
// clientsFile is clients.json, with each client on a line of its own.
type clientsFile struct {
Version int `json:"version"`
Clients []ratelimit.Client `json:"clients"`
}
// lookupsFile is lookups.json, with each answer on a line of its own.
type lookupsFile struct {
Version int `json:"version"`
Lookups []lookup.Answer `json:"lookups"`
}
// stateFile is the struct of a state file. Once the file is decoded, its
// check refuses the first entry without a field it needs, which would
// otherwise be read as something the entry does not say. data is the
// file, for a field that may be null or "" but not left out, which the
// struct cannot tell apart.
type stateFile interface {
check(data []byte) error
}
// Load checks that files can be written in Dir, and reads the state files
// in it into the ledger, the limiter and GeoJS. A missing file is empty
// state, as on a first start. A file that does not parse, has an unknown
// version, or has an entry without a field it needs, is an error that
// names the file and, where the JSON decoder tells it, the line and
// column, or else the entry.
func Load(params Params) (*Files, error) {
err := checkWritable(params.Dir)
if err != nil {
return nil, fmt.Errorf("SWWAF_STATE_DIR cannot be written: %w", err)
}
f := &Files{params: params, sums: map[string][sha256.Size]byte{}}
bansRead, bansErr := f.read(bansJSON)
clientsRead, clientsErr := f.read(clientsJSON)
lookupsRead, lookupsErr := f.read(lookupsJSON)
err = errors.Join(bansErr, clientsErr, lookupsErr)
if err != nil {
return nil, err
}
params.ProcessLog.Info("read the state files", "directory", params.Dir,
"bans", bansRead, "clients", clientsRead, "lookups", lookupsRead)
return f, nil
}
// Run writes bans.json WriteDelay after a ban is made, with every ban
// made in between, and every file every CounterInterval, until ctx is
// done. A write that fails is logged, and the file is written again at
// its next write. Each write takes in an admin's edit of its file first,
// as writeFile describes.
func (f *Files) Run(ctx context.Context) {
interval := time.NewTicker(f.params.CounterInterval)
defer interval.Stop()
var bansDue <-chan time.Time // nil while no ban waits to be written
for {
select {
case <-ctx.Done():
return
case <-f.params.Ledger.Changed():
if bansDue == nil {
bansDue = time.After(f.params.WriteDelay)
}
case <-bansDue:
bansDue = nil
f.logFailure(f.writeFile(bansJSON))
case <-interval.C:
f.logFailure(f.WriteAll())
}
}
}
// WriteAll writes every state file, as smallwebwaf stops. A file that
// fails does not keep the others from being written.
func (f *Files) WriteAll() error {
return errors.Join(f.writeFile(bansJSON), f.writeFile(clientsJSON),
f.writeFile(lookupsJSON))
}
// Watch watches Dir until ctx is done, and takes in an admin's edit of a
// state file as soon as it is saved: what the file holds replaces what
// smallwebwaf held for it. An edit that does not parse is left for the
// file's next write, which sets it aside, since a file can be read while
// an editor is still writing it. If Dir cannot be watched, that is
// logged, and an edit is taken in only before its file is written.
func (f *Files) Watch(ctx context.Context) {
watcher, err := fsnotify.NewWatcher()
if err == nil {
defer func() {
_ = watcher.Close()
}()
err = watcher.Add(f.params.Dir)
}
if err != nil {
f.params.ProcessLog.Error("cannot watch the state files for edits",
"error", err.Error())
return
}
f.params.ProcessLog.Info("watching the state files for edits",
"directory", f.params.Dir)
for {
select {
case <-ctx.Done():
return
case event := <-watcher.Events:
switch name := filepath.Base(event.Name); name {
case bansJSON, clientsJSON, lookupsJSON:
f.fileChanged(name)
}
case err = <-watcher.Errors:
f.params.ProcessLog.Warn("watching the state files failed",
"error", err.Error())
}
}
}
// logFailure logs a write that failed.
func (f *Files) logFailure(err error) {
if err != nil {
f.params.ProcessLog.Error("writing the state files failed",
"error", err.Error())
}
}
// fileChanged takes in what the state file name holds, as Watch sees it
// change, if that is an edit made since smallwebwaf last read or wrote
// the file. A file that cannot be read or does not parse is left for its
// next write.
func (f *Files) fileChanged(name string) {
f.mu.Lock()
defer f.mu.Unlock()
data, changed, err := f.readChanged(name)
if err != nil || !changed {
return
}
_ = f.takeInEdit(name, data)
}
// takeInEdit takes in data, an edit of the state file name, as takeIn
// does, and counts and logs it. Every edit taken in while smallwebwaf
// runs, by Watch or by a write, is taken in here. An edit that does not
// parse is neither counted nor logged, and takeIn's error returned.
func (f *Files) takeInEdit(name string, data []byte) error {
_, err := f.takeIn(name, data)
if err != nil {
return err
}
// Counted before it is logged, so that the count is there once the
// log line is.
f.params.Metrics.StateFileEditTakenIn(name)
f.params.ProcessLog.Info("took in an edit of a state file",
"file", filepath.Join(f.params.Dir, name))
return nil
}
// read takes in the state file name at start, and returns how many
// entries it holds. A missing file holds none.
func (f *Files) read(name string) (int, error) {
data, changed, err := f.readChanged(name)
if err != nil || !changed {
return 0, err
}
return f.takeIn(name, data)
}
// readChanged returns what the state file name holds, and whether that
// has changed since smallwebwaf last read or wrote the file, as it has
// for a file smallwebwaf never read or wrote. A missing file has not
// changed: it is written again at its next write.
func (f *Files) readChanged(name string) ([]byte, bool, error) {
path := filepath.Join(f.params.Dir, name)
data, err := os.ReadFile(path) //nolint:gosec // a state file, in SWWAF_STATE_DIR
if errors.Is(err, fs.ErrNotExist) {
return nil, false, nil
}
if err != nil {
return nil, false, err
}
return data, sha256.Sum256(data) != f.sums[name], nil
}
// takeIn parses data, what the state file name holds, puts it into the
// part that keeps that state, in place of what the part held, and returns
// how many entries the file holds. An error names the file and, where the
// JSON decoder tells it, the line and column, or else the entry.
func (f *Files) takeIn(name string, data []byte) (int, error) {
path := filepath.Join(f.params.Dir, name)
var entries int
switch name {
case bansJSON:
var file bansFile
err := parse(path, data, &file)
if err != nil {
return 0, err
}
held := make([]bans.Ban, 0, len(file.Bans))
for _, entry := range file.Bans {
held = append(held, entry.ban())
}
f.params.Ledger.Load(held)
entries = len(held)
case clientsJSON:
var file clientsFile
err := parse(path, data, &file)
if err != nil {
return 0, err
}
f.params.Limiter.Load(file.Clients, f.params.Now())
entries = len(file.Clients)
case lookupsJSON:
var file lookupsFile
err := parse(path, data, &file)
if err != nil {
return 0, err
}
f.params.GeoJS.Load(file.Lookups)
entries = len(file.Lookups)
}
f.sums[name] = sha256.Sum256(data)
return entries, nil
}
// writeFile writes the state file name from what smallwebwaf holds. An
// edit made since smallwebwaf last read or wrote the file is taken in
// first, so that it is not overwritten, or set aside if it does not
// parse. A file that cannot be read, or an edit that cannot be set
// aside, is left as it is, and the write given up. Every write is counted
// in the metrics, and one that fails or is given up as a failure.
func (f *Files) writeFile(name string) error {
f.mu.Lock()
defer f.mu.Unlock()
data, changed, err := f.readChanged(name)
if err == nil && changed {
err = f.takeInEdit(name, data)
if err != nil {
err = f.setAside(name, err)
}
}
if err == nil {
data, err = f.encode(name)
if err != nil {
err = fmt.Errorf("encode %s: %w", name, err)
}
}
if err == nil {
err = write(f.params.Dir, name, data)
}
if err == nil {
// The file holds data from here on, even if the directory sync
// fails, so that its next read does not take it for an admin's
// edit.
f.sums[name] = sha256.Sum256(data)
err = syncDirectory(f.params.Dir)
}
f.params.Metrics.StateFileWritten(name, len(data), err)
return err
}
// setAside renames the state file name, an edit that does not parse with
// parseErr, to name.bad, for the admin to mend, and logs it with where in
// the file the error is. If the rename fails, the edit is left as it is,
// and the error returned is parseErr joined with the rename's.
func (f *Files) setAside(name string, parseErr error) error {
path := filepath.Join(f.params.Dir, name)
err := os.Rename(path, path+".bad")
if err != nil {
return errors.Join(parseErr, err)
}
f.params.ProcessLog.Error("set aside an edit of a state file that does not parse",
"file", path+".bad", "error", parseErr.Error())
f.params.Metrics.StateFileEditSetAside(name)
return nil
}
// encode returns the state file name as smallwebwaf writes it, from a
// snapshot of the part that keeps that state.
func (f *Files) encode(name string) ([]byte, error) {
switch name {
case bansJSON:
held := f.params.Ledger.Snapshot()
file := bansFile{Version: version, Bans: make([]banEntry, 0, len(held))}
for _, ban := range held {
file.Bans = append(file.Bans, newBanEntry(ban))
}
data, err := json.MarshalIndent(file, "", " ")
if err != nil {
return nil, err
}
return append(data, '\n'), nil
case clientsJSON:
return encodeOnePerLine("clients", f.params.Limiter.Snapshot())
default: // lookups.json
return encodeOnePerLine("lookups", f.params.GeoJS.Snapshot())
}
}
// newBanEntry returns ban as bans.json holds it.
func newBanEntry(ban bans.Ban) banEntry {
entry := banEntry{Netblock: ban.Netblock, Start: ban.Start, Notes: ban.Notes}
if !ban.Permanent() {
entry.Expires = &ban.Expires
}
return entry
}
// ban returns the ban an entry of bans.json holds.
func (e banEntry) ban() bans.Ban {
ban := bans.Ban{Netblock: e.Netblock, Start: e.Start, Notes: e.Notes}
if e.Expires != nil {
ban.Expires = *e.Expires
}
return ban
}
// check refuses a ban without a netblock, which would refuse every IPv6
// client, a start, from which the length of the netblock's next ban is
// worked out, or an expires, which would make it permanent. A permanent
// ban's expires is null, which Bans cannot tell from a missing one, so
// each expires is read again as written.
func (f *bansFile) check(data []byte) error {
var written struct {
Bans []struct {
Expires json.RawMessage `json:"expires"`
} `json:"bans"`
}
err := json.Unmarshal(data, &written)
if err != nil {
return err
}
for i, entry := range f.Bans {
switch {
case !entry.Netblock.IsValid():
return missing(i, "netblock")
case entry.Start.IsZero():
return missing(i, "start")
case written.Bans[i].Expires == nil:
return missing(i, "expires")
}
}
return nil
}
// check refuses a client without its address, which would count nobody's
// requests, or with requests in a window but no start, which would drop
// them and give the client a fresh allowance.
func (f *clientsFile) check([]byte) error {
for i, client := range f.Clients {
switch {
case !client.Client.IsValid():
return missing(i, "client")
case countsWithoutStart(client.Minute):
return missing(i, "minute.start")
case countsWithoutStart(client.Hour):
return missing(i, "hour.start")
case countsWithoutStart(client.Day):
return missing(i, "day.start")
}
}
return nil
}
// check refuses an answer without a client, which would answer for
// nobody, a country, which would place the client nowhere, or the time
// GeoJS gave it, which would drop it. "" is the country of a client
// GeoJS cannot place, which Lookups cannot tell from a missing one, so
// each country is read again as written.
func (f *lookupsFile) check(data []byte) error {
var written struct {
Lookups []struct {
Country *string `json:"country"`
} `json:"lookups"`
}
err := json.Unmarshal(data, &written)
if err != nil {
return err
}
for i, answer := range f.Lookups {
switch {
case !answer.Client.IsValid():
return missing(i, "client")
case written.Lookups[i].Country == nil:
return missing(i, "country")
case answer.Answered.IsZero():
return missing(i, "answered")
}
}
return nil
}
// countsWithoutStart reports whether b holds requests but no start, which
// places them in time.
func countsWithoutStart(b ratelimit.Buckets) bool {
return b.Start.IsZero() && (b.Current != 0 || b.Previous != 0)
}
// missing returns the error for entry i, counted from 0, of a state file,
// which has no field.
func missing(i int, field string) error {
return fmt.Errorf("entry %d %w %q", i+1, errMissing, field)
}
// encodeOnePerLine encodes a state file whose entries, under key, are one
// to a line, so that grep shows everything about one client.
func encodeOnePerLine[E any](key string, entries []E) ([]byte, error) {
var b bytes.Buffer
fmt.Fprintf(&b, "{\n \"version\": %d,\n %q: [", version, key)
for i, entry := range entries {
line, err := json.Marshal(entry)
if err != nil {
return nil, err
}
if i > 0 {
b.WriteString(",")
}
b.WriteString("\n ")
b.Write(line)
}
b.WriteString("\n ]\n}\n")
return b.Bytes(), nil
}
// checkWritable makes a file in dir and removes it again.
func checkWritable(dir string) error {
file, err := os.CreateTemp(dir, "write-check-*")
if err != nil {
return err
}
return errors.Join(file.Close(), os.Remove(file.Name()))
}
// parse reads data, what the state file at path holds, into file, a
// pointer to that file's struct, and checks its entries.
func parse(path string, data []byte, file stateFile) error {
// The version is read first, so that a file of another version is
// refused for that, and not for an entry this version cannot read.
var header struct {
Version int `json:"version"`
}
err := json.Unmarshal(data, &header)
if err == nil && header.Version != version {
err = fmt.Errorf("%w %d, where this smallwebwaf reads version %d",
errVersion, header.Version, version)
}
if err == nil {
decoder := json.NewDecoder(bytes.NewReader(data))
// A field this version does not know is most likely misspelt, and
// its value would be lost without a word.
decoder.DisallowUnknownFields()
err = decoder.Decode(file)
}
if err == nil {
err = file.check(data)
}
if err != nil {
return fmt.Errorf("%s%s: %w", path, position(data, err), err)
}
return nil
}
// position returns where in data err was found, as ", line L, column C"
// of the last byte the JSON decoder read, or "" when err does not tell.
func position(data []byte, err error) string {
var (
syntaxErr *json.SyntaxError
typeErr *json.UnmarshalTypeError
read int64
)
switch {
case errors.As(err, &syntaxErr):
read = syntaxErr.Offset
case errors.As(err, &typeErr):
read = typeErr.Offset
default:
return ""
}
before := data[:max(min(read, int64(len(data)))-1, 0)]
line := bytes.Count(before, []byte("\n")) + 1
column := len(before) - bytes.LastIndexByte(before, '\n')
return fmt.Sprintf(", line %d, column %d", line, column)
}
// write writes data to the file name in dir so that a crash at any
// moment leaves either the old file or the new one, whole: data goes to a
// temporary file in the same directory, which is synced and renamed over
// name. syncDirectory must follow, so that the rename lasts.
func write(dir, name string, data []byte) error {
path := filepath.Join(dir, name)
temporary := path + ".tmp"
err := writeSynced(temporary, data)
if err == nil {
err = os.Rename(temporary, path)
}
if err != nil {
_ = os.Remove(temporary)
}
return err
}
// syncDirectory syncs dir to the disk, so that a rename in it lasts.
func syncDirectory(dir string) error {
directory, err := os.Open(dir) //nolint:gosec // SWWAF_STATE_DIR itself
if err != nil {
return err
}
return errors.Join(directory.Sync(), directory.Close())
}
// writeSynced writes data to the file at path, and syncs it to the disk.
func writeSynced(path string, data []byte) error {
//nolint:gosec // a state file's temporary file, in SWWAF_STATE_DIR
file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, fileMode)
if err != nil {
return err
}
_, err = file.Write(data)
if err == nil {
err = file.Sync()
}
return errors.Join(err, file.Close())
}
internal/state/state_test.go
+1217
View File
File diff suppressed because it is too large Load Diff
internal/state/write_internal_test.go
+35
View File
@@ -0,0 +1,35 @@
package state
import (
"os"
"path/filepath"
"testing"
)
// The test is on write itself: a state file is read before it is
// written, and a directory in its place fails that read first.
func TestFailedRenameLeavesNoTemporaryFile(t *testing.T) {
t.Parallel()
dir := t.TempDir()
// A directory named bans.json cannot be renamed over.
err := os.Mkdir(filepath.Join(dir, bansJSON), 0o700)
if err != nil {
t.Fatalf("mkdir: %v", err)
}
err = write(dir, bansJSON, []byte("{}\n"))
if err == nil {
t.Error("writing over a directory did not fail")
}
entries, err := os.ReadDir(dir)
if err != nil {
t.Fatalf("read %s: %v", dir, err)
}
if len(entries) != 1 || entries[0].Name() != bansJSON {
t.Errorf("%s holds %v, want only bans.json", dir, entries)
}
}
script/bootstrap
+1
View File
@@ -131,6 +131,7 @@ main() {
if missing make; then pkg_install gnumake make make make; fi
if missing git; then pkg_install git git git git; fi
if missing curl; then pkg_install curl curl curl curl; fi
if missing gofmt; then pkg_install go golang go go; fi
ensure_node
script/cibuild
+2 -3
View File
@@ -16,9 +16,8 @@ main() {
"$SCRIPT_DIR/check"
# Own line: a failing command substitution inside an argument does
# not trip `set -e`, so the inline form degrades silently to an
# empty constant. VERSION is computed here because .dockerignore
# excludes .git, so `git describe` in a build stage yields an empty
# version without failing.
# empty constant. The VERSION build argument takes precedence over
# the version a build stage derives from the .git in the context.
version="$(git describe --tags --always --dirty 2>/dev/null || true)"
[ -n "$version" ] || version="unknown"
docker build --no-cache \
script/docker
+2 -3
View File
@@ -12,9 +12,8 @@ main() {
cd "$ROOT"
# Own line: a failing command substitution inside an argument does
# not trip `set -e`, so the inline form degrades silently to an
# empty constant. VERSION is computed here because .dockerignore
# excludes .git, so `git describe` in a build stage yields an empty
# version without failing.
# empty constant. The VERSION build argument takes precedence over
# the version a build stage derives from the .git in the context.
version="$(git describe --tags --always --dirty 2>/dev/null || true)"
[ -n "$version" ] || version="unknown"
docker build --no-cache \
script/example-app
Executable
+121
View File
@@ -0,0 +1,121 @@
#!/bin/sh
# script/example-app: build the image, and on it the example app in
# deploy/example-app, then run the app's container with a volume for the
# state files and check that the health check passes, that a request is
# served through smallwebwaf, that a second one in a minute bans the
# client, that `sv stop` stops smallwebwaf in order, that `docker stop`
# stops the container without having to kill it, and that a new
# container on the same volume still refuses the banned client. The
# containers, the volume and both images are removed however the script
# ends. Building the app needs network access, for nixpkgs' binary cache.
# script/check does not run this.
set -eu
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
# Named after this run, so that runs in other clones on the same host
# never touch each other's.
NAME="$("$SCRIPT_DIR/projectname")-example-$$"
IMAGE="$NAME-base"
APP_IMAGE="$NAME-app"
CONTAINER="$NAME"
VOLUME="$NAME-state"
cleanup() {
docker rm --force "$CONTAINER" >/dev/null 2>&1 || true
docker volume rm --force "$VOLUME" >/dev/null 2>&1 || true
docker rmi --force "$APP_IMAGE" "$IMAGE" >/dev/null 2>&1 || true
}
fail() {
echo "example-app: $*; the container's output:" >&2
docker logs "$CONTAINER" >&2 || true
exit 1
}
# wait_for <what fails> <command>...: run the command every second until
# it succeeds, for at most a minute.
wait_for() {
failure="$1"
shift
tries=0
until "$@"; do
tries=$((tries + 1))
[ "$tries" -lt 60 ] || fail "$failure"
sleep 1
done
}
healthy() {
status="$(docker inspect --format '{{.State.Health.Status}}' "$CONTAINER")"
[ "$status" = healthy ]
}
# logged <text>: the container's output holds text.
logged() {
docker logs "$CONTAINER" 2>&1 | grep -qF "$1"
}
# start_container: run the app's container, with the state files on the
# volume and a rate limit of one request a minute, and wait until it is
# healthy.
start_container() {
docker run --detach --name "$CONTAINER" --publish 127.0.0.1::8080 \
--volume "$VOLUME:/var/lib/smallwebwaf" \
--env SWWAF_RATE_LIMIT_PER_MINUTE=1 \
"$APP_IMAGE" >/dev/null
wait_for "the health check did not pass" healthy
address="$(docker port "$CONTAINER" 8080/tcp)"
}
# refused: a request to the container gets 403, SWWAF_BAN_RESPONSE's
# default.
refused() {
code="$(curl --silent --output /dev/null --write-out '%{http_code}' \
--max-time 10 "http://$address/")" || true
[ "$code" = 403 ]
}
main() {
cd "$ROOT"
trap cleanup EXIT
trap 'exit 1' HUP INT TERM
docker build --no-cache -t "$IMAGE" .
docker build --no-cache --build-arg SMALLWEBWAF_IMAGE="$IMAGE" \
-t "$APP_IMAGE" deploy/example-app
docker volume create "$VOLUME" >/dev/null
start_container
echo "example-app: the health check passes"
page="$(curl --fail --silent --show-error --max-time 10 "http://$address/")" ||
fail "no answer on port 8080"
[ "$page" = "hello from the example app" ] || fail "port 8080 answered $page"
wait_for "smallwebwaf logged no request it forwarded" logged '"action":"forward"'
echo "example-app: smallwebwaf passes a request to the app and its answer back"
refused || fail "a second request in a minute was not refused"
wait_for "smallwebwaf logged no ban" logged '"action":"rate_limited"'
echo "example-app: a second request in a minute bans the client"
docker exec "$CONTAINER" sv stop smallwebwaf >/dev/null ||
fail "sv stop smallwebwaf failed"
wait_for "smallwebwaf did not stop in order" logged '"msg":"stopped"'
echo "example-app: sv stop stops smallwebwaf in order"
docker stop "$CONTAINER" >/dev/null
status="$(docker inspect --format '{{.State.ExitCode}}' "$CONTAINER")"
[ "$status" = 0 ] || fail "docker stop left exit status $status"
echo "example-app: docker stop stops the container in order"
docker rm "$CONTAINER" >/dev/null
start_container
refused || fail "the new container let the banned client through"
wait_for "smallwebwaf logged no request refused under the ban" \
logged '"action":"banned"'
echo "example-app: a new container on the same volume keeps the ban"
}
main "$@"
script/run
+7 -1
View File
@@ -1,6 +1,7 @@
#!/bin/sh
# script/run: build bin/smallwebwaf with script/build and run it, with
# the settings in the environment.
# the settings in the environment. Unless SWWAF_STATE_DIR is set, the
# state files go in bin/state, beside the binary.
set -eu
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -8,6 +9,11 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
main() {
"$SCRIPT_DIR/build"
if [ -z "${SWWAF_STATE_DIR+set}" ]; then
SWWAF_STATE_DIR="$ROOT/bin/state"
export SWWAF_STATE_DIR
mkdir -p "$SWWAF_STATE_DIR"
fi
exec "$ROOT/bin/smallwebwaf"
}
share/smallwebwaf.run
Executable
+16
View File
@@ -0,0 +1,16 @@
#!/usr/bin/env bash
set -euo pipefail
# runit's run script for smallwebwaf, run again whenever smallwebwaf
# exits; the wait spaces out the restarts. The state directory and every
# file in it are given to the smallwebwaf user, so that a volume mounted
# there needs no change of owner; chown -R changes a symbolic link itself,
# never what it points to. exec, so that the signal `sv stop` sends
# reaches smallwebwaf itself.
main() {
sleep 1
chown -R smallwebwaf:smallwebwaf "${SWWAF_STATE_DIR:-/var/lib/smallwebwaf}"
exec chpst -u smallwebwaf:smallwebwaf /usr/local/bin/smallwebwaf
}
main "$@"