Request tags, with refusing and limits per tag (closes #175)

Each request gets sorted tags from the lookup, new address lists, the
reputation sources and the rule matches, logged as `tags`. New settings:
`SWW_TAG_LISTS`, `SWW_TAG_DENY`, `SWW_TAG_LIMIT_PERCENT`. They replace
`SWW_ASN_LIMIT_PERCENT`, `SWW_COUNTRY_LIMIT_PERCENT` and
`SWW_DENIED_COUNTRIES`. New heuristics `tag_lists` and `tag_deny`; the
latter runs before the rate limits and again after the Core Rule Set.

Model: opus-5-5

README.md

@@ -257,14 +257,14 @@ Every setting the code reads, with its default:
 | `SWW_LOOKUP_DB_PATH`                     | empty                                                                          | The IPinfo Lite database file, in its `.mmdb` form, read while the source is `file`.                                                                              |
 | `SWW_LOOKUP_TIMEOUT`                     | `800ms`                                                                        | How long a request waits for its client's first GeoJS answer when a setting needs it, and how long a request to GeoJS may take.                                   |
 | `SWW_ADD_LOOKUP_HEADERS`                 | `false`                                                                        | `true` passes the app the client's AS number and country in `X-Client-ASN` and `X-Client-Country`.                                                                |
-| `SWW_DENIED_COUNTRIES`                   | empty                                                                          | Countries whose clients are refused, such as `cn,ru`.                                                                                                             |
 | `SWW_EXCLUSIVELY_ALLOWED_COUNTRIES`      | empty                                                                          | When set, the only countries whose clients get through; a client the lookup cannot place is refused too.                                                          |
-| `SWW_ASN_LIMIT_PERCENT`                  | empty                                                                          | AS numbers whose clients get a percentage of every request and byte limit, such as `AS14061:50,AS16276:25`.                                                       |
-| `SWW_COUNTRY_LIMIT_PERCENT`              | empty                                                                          | The same by country, such as `cn:25`.                                                                                                                             |
-| `SWW_ASN_BYTES_PERCENT`                  | empty                                                                          | A percentage of the byte limits alone for the AS numbers listed, in place of their `SWW_ASN_LIMIT_PERCENT`.                                                       |
-| `SWW_COUNTRY_BYTES_PERCENT`              | empty                                                                          | A percentage of the byte limits alone for the countries listed, in place of their `SWW_COUNTRY_LIMIT_PERCENT`.                                                    |
+| `SWW_TAG_LISTS`                          | empty                                                                          | Address lists that each add a tag to their clients' requests, as `name=URL` pairs, such as `torexit=https://example.com/tor.txt`.                                 |
+| `SWW_TAG_DENY`                           | empty                                                                          | Tags whose requests are refused, such as `torexit,country=CN`.                                                                                                    |
+| `SWW_TAG_LIMIT_PERCENT`                  | empty                                                                          | Tags whose clients get a percentage, from 1 to 99, of every request and byte limit, such as `vpn:50,asn=14061:25`; the lowest applies.                            |
+| `SWW_ASN_BYTES_PERCENT`                  | empty                                                                          | A percentage of the byte limits alone for the AS numbers listed, in place of their `asn=` tag's percentage.                                                       |
+| `SWW_COUNTRY_BYTES_PERCENT`              | empty                                                                          | A percentage of the byte limits alone for the countries listed, in place of their `country=` tag's percentage.                                                    |
 | `SWW_UNKNOWN_LIMIT_PERCENT`              | `100`                                                                          | The percentage of every limit a client without a country gets.                                                                                                    |
-| `SWW_ASN_LIMIT_PERCENT_URL`              | unset                                                                          | The URL of a text file of `AS<number>:<percent>` lines, fetched like a blocklist; where it and `SWW_ASN_LIMIT_PERCENT` both give a percentage, the lower applies. |
+| `SWW_ASN_LIMIT_PERCENT_URL`              | unset                                                                          | The URL of a text file of `AS<number>:<percent>` lines, fetched like a blocklist; each line counts as an `asn=` tag in `SWW_TAG_LIMIT_PERCENT` (the lowest wins). |
 | `SWW_RULES_DIR`                          | `/etc/sww/rules.d`                                                             | The directory of the rule files, read at start and again when a file there changes.                                                                               |
 | `SWW_RULES_ENABLED`                      | `true`                                                                         | `false` reads no rule file.                                                                                                                                       |
 | `SWW_TRAP_PATHS`                         | empty                                                                          | Paths only scanners ask for, such as `/wp-login.php,/xmlrpc.php`; a request for one bans the client.                                                              |
@@ -414,8 +414,7 @@ services:
             SWW_RATE_LIMIT_PER_HOUR: "600"
             SWW_RATE_LIMIT_PER_DAY: "3000"
             # Hosting networks and one country get a share of those limits.
-            SWW_ASN_LIMIT_PERCENT: AS14061:50,AS16276:25
-            SWW_COUNTRY_LIMIT_PERCENT: cn:25
+            SWW_TAG_LIMIT_PERCENT: asn=14061:50,asn=16276:25,country=CN:25
             # Paths only scanners ask for; one request bans the client.
             SWW_TRAP_PATHS: /wp-login.php,/xmlrpc.php
             # Answer a refused client with 429 rather than 403.
@@ -507,31 +506,34 @@ of the request reaches the app.
 
 `discriminator` takes the checks:
 
-3. The static lists, `SWW_ALLOW_NETS` and `SWW_DENY_NETS`.
-4. The bans.
-5. The lookup of the client's AS number and country.
-6. The country lists.
-7. The reputation sources.
-8. The client's limit percentage, from its AS number, its country or a
-   reputation hit.
-9. The rate limits.
-10. The trap paths.
-11. The rule files.
-12. The header limits, and then the Core Rule Set.
-13. A path under `/_sww/` is answered `404`, so that the app never sees that
+3. The tag lists.
+4. The static lists, `SWW_ALLOW_NETS` and `SWW_DENY_NETS`.
+5. The bans.
+6. The lookup of the client's AS number and country.
+7. The country list.
+8. The reputation sources.
+9. The tag refusals of `SWW_TAG_DENY`.
+10. The client's limit percentage, from its tags, its AS number, its country or
+    a reputation hit.
+11. The rate limits.
+12. The trap paths.
+13. The rule files.
+14. The header limits, and then the Core Rule Set.
+15. The tag refusals again, so that `exploitsignature` can refuse too.
+16. A path under `/_sww/` is answered `404`, so that the app never sees that
     prefix.
 
 `rproxy` takes the rest, with `discriminator` counting at the end:
 
-14. The request is passed to the app, streaming.
-15. After the answer, `rproxy` sends `discriminator` a report with the status
+17. The request is passed to the app, streaming.
+18. After the answer, `rproxy` sends `discriminator` a report with the status
     and the bytes each way. For an allowed request, `discriminator` counts the
     bytes toward the byte limits and adds the request to the client's history.
 
 A refused visitor is answered with `SWW_BAN_RESPONSE`. A `block` rule or a Core
 Rule Set match answers `403` and bans nobody, since the Core Rule Set has false
 positives; such refusals count toward `SWW_ERROR_BURST_THRESHOLD` instead. A
-request over the header limits of step 12 is answered `431`, and bans nobody
+request over the header limits of step 14 is answered `431`, and bans nobody
 either. `rproxy` itself answers `405` to a method it does not pass on, and the
 status for a size or time limit, such as `413` for a body too large.
 
@@ -550,6 +552,21 @@ status for a size or time limit, such as `413` for a body too large.
   bans. An admin adds, keeps or lifts a ban by editing `bans.json` or through
   the ban endpoints (see [`docs/admin-endpoints.md`](docs/admin-endpoints.md)).
 
+### Request tags
+
+Each request gets tags from what `discriminator` knows of its client, written in
+the `tags` field of its log line:
+
+- `asn=<number>` and `country=<code>`, from the lookup;
+- one tag per list of `SWW_TAG_LISTS` that holds the client, such as `torexit`
+  or `vpn=mullvad`;
+- `crowdsec`, `dnsbl=<zone>` and `abuseipdb`, when that reputation source lists
+  the client;
+- `exploitsignature`, when a rule file or the Core Rule Set matched the request.
+
+`SWW_TAG_DENY` refuses requests by tag, and `SWW_TAG_LIMIT_PERCENT` lowers a
+client's limits by tag. See "Request tags" in [`SPEC.md`](SPEC.md).
+
 ### Attack detection
 
 - The Core Rule Set reads the method, the URL with its query string, and the

SPEC.md

@@ -119,9 +119,9 @@ to them.
 
 ## What happens to a request
 
-`rproxy` runs steps 1, 2 and 14, and sends the report of step 15.
-`discriminator` runs steps 3 to 13, and does the counting of step 15. The first
-step that produces a final answer ends the checks. Step 15 runs for each request
+`rproxy` runs steps 1, 2 and 17, and sends the report of step 18.
+`discriminator` runs steps 3 to 16, and does the counting of step 18. The first
+step that produces a final answer ends the checks. Step 18 runs for each request
 `discriminator` answers with `allow`, `deny` or `close`. `rproxy`'s size and
 time limits apply to the whole exchange. Each step names the section that holds
 its rules. A step that names a heuristic in parentheses runs that heuristic. The
@@ -143,46 +143,54 @@ request log's `heuristic` field gives that name. `refusal_limit` and
     - An IPv6 client is its group: the netblock of `SWW_IPV6_GROUP_PREFIX`
       around its address, a /64 by default, since one abuser usually controls a
       whole /64. A client is therefore one IPv4 address or one IPv6 group.
-3. The static lists. A client in `SWW_ALLOW_NETS` skips steps 4 to 12, the byte
+3. The tag lists (`tag_lists`; see "Request tags"). Each list that holds the
+   client adds its tag. A client in `SWW_ALLOW_NETS` gets no tag.
+4. The static lists. A client in `SWW_ALLOW_NETS` skips steps 5 to 15, the byte
    limits and the error burst. A client in `SWW_DENY_NETS` is refused
    (`deny_nets`); a client in both lists is let through.
-4. Bans. A client under a ban is refused (`active_ban`; see "Bans").
-5. The lookup, unless `SWW_LOOKUP_SOURCE` is `off` (see "Lookup of AS number and
+5. Bans. A client under a ban is refused (`active_ban`; see "Bans").
+6. The lookup, unless `SWW_LOOKUP_SOURCE` is `off` (see "Lookup of AS number and
    country"). The request goes on at once. It waits for the first GeoJS answer,
    up to `SWW_LOOKUP_TIMEOUT`, only when one of these needs it:
-    - a country list;
+    - the country list;
     - a biased threshold;
+    - `SWW_TAG_DENY` or `SWW_TAG_LIMIT_PERCENT` naming an `asn=` or `country=`
+      tag;
     - `SWW_ADD_LOOKUP_HEADERS`.
 
     A request that ends before the answer comes is logged without it.
 
-6. The country lists (`countries`; see "Country lists").
-7. The reputation sources (see "Reputation"), in this order:
+7. The country list (`countries`; see "Country list").
+8. The reputation sources (see "Reputation"), in this order:
     - A client on a fetched blocklist gets `SWW_BLOCKLIST_ACTION`
       (`blocklists`).
     - A client on the CrowdSec decision list is banned (`crowdsec`).
     - A client listed by a DNS blocklist gets `SWW_REPUTATION_ACTION` (`dnsbl`).
     - A client scored at least `SWW_ABUSEIPDB_MIN_SCORE` by AbuseIPDB gets
       `SWW_REPUTATION_ACTION` (`abuseipdb`).
-8. The client's limit percentage (see "Biased thresholds").
-9. Rate limiting (`rate_limits`; see "Request rate limits, per client"). A
+9. The tag refusals (`tag_deny`; see "Request tags"). A request carrying a tag
+   in `SWW_TAG_DENY` is refused.
+10. The client's limit percentage (see "Biased thresholds").
+11. Rate limiting (`rate_limits`; see "Request rate limits, per client"). A
     request over a limit times the percentage is refused and bans the client.
-10. The trap paths (`trap_paths`; see "Attack detection"). A request for one is
+12. The trap paths (`trap_paths`; see "Attack detection"). A request for one is
     refused and bans the client.
-11. The rule files (`rule_files`; see "Rule files"). Matching stops at the first
+13. The rule files (`rule_files`; see "Rule files"). Matching stops at the first
     rule that refuses.
-12. The header limits (`header_limits`; see "Answering in time"), and then the
+14. The header limits (`header_limits`; see "Answering in time"), and then the
     Core Rule Set (`core_rule_set`; see "Attack detection"). A Core Rule Set
     match is refused with `403` while `SWW_WAF_MODE` is `block`, and only logged
     and alerted while it is `detect`.
-13. A path under `/_sww/` is answered `404`, so that the app never sees that
+15. The tag refusals again (`tag_deny`), so that `exploitsignature` can refuse
+    too.
+16. A path under `/_sww/` is answered `404`, so that the app never sees that
     prefix.
-14. `rproxy` passes the request to `SWRP_UPSTREAM_URL`, streaming (see "Passing
+17. `rproxy` passes the request to `SWRP_UPSTREAM_URL`, streaming (see "Passing
     a request to the app"). With `SWW_ADD_LOOKUP_HEADERS`, `X-Client-ASN` and
     `X-Client-Country` are added for the app's own logs; a header whose value is
     unknown is left out. Whatever that setting says, any such header the client
     sent is removed.
-15. After the visitor's answer has ended, `rproxy` sends the report (see "The
+18. After the visitor's answer has ended, `rproxy` sends the report (see "The
     report"). `discriminator` then counts:
     - For a request it allowed, the response bytes, the request bytes or both
       are added to the byte counters, as `SWW_BYTES_COUNT` says. For a
@@ -285,7 +293,8 @@ no offence:
 
 - `SWW_DENY_NETS`;
 - a blocklist or reputation hit whose action is `deny`;
-- the country lists.
+- the country list;
+- `SWW_TAG_DENY`.
 
 Every ban carries notes with what an admin needs to decide whether to lift it,
 drawn from what `discriminator` already knows. No lookup is made for the notes
@@ -392,7 +401,7 @@ Conventions:
 
 ### Static lists
 
-- `SWW_ALLOW_NETS` skips the checks step 3 names, for monitoring or the owner's
+- `SWW_ALLOW_NETS` skips the checks step 4 names, for monitoring or the owner's
   own networks. `SWW_RATE_LIMIT_EXEMPT_NETS` bypasses the request and byte
   limits only; the error burst, attack detection and bans still apply.
 - Many people can share one address, as in an office, on a mobile carrier or
@@ -442,7 +451,7 @@ the same way.
 By default there is no minute limit, so a client can download in a burst at full
 speed. The hour limit defaults to 50 GiB and the day limit to 100 GiB. They
 allow several downloads of a few GiB each. A response's bytes are counted when
-it ends (see step 15).
+it ends (see step 18).
 
 ### Lookup of AS number and country
 
@@ -471,12 +480,12 @@ service that keeps its visitors' addresses on its own host.
   dropped from that table. The answer reaches the client's history and ban notes
   when it comes.
 - `SWW_LOOKUP_TIMEOUT` is how long a visitor's request waits for its client's
-  first answer, when a setting needs it (see step 5). It also bounds each
+  first answer, when a setting needs it (see step 6). It also bounds each
   request to GeoJS. A client whose answer has not come in time counts as unknown
   until it comes, and its later requests do not wait. Its address is asked about
   again in the background.
 - A client the lookup cannot place has an unknown country and AS number, which
-  the country lists and the biased thresholds treat as described there. Nothing
+  the country list and the biased thresholds treat as described there. Nothing
   else treats it differently.
 - GeoJS publishes no rate limit, but its terms forbid "an excessive amount of
   API requests", judged by GeoJS alone, and let it block a caller. While GeoJS
@@ -496,12 +505,12 @@ service that keeps its visitors' addresses on its own host.
   `file_error` alert and ignored. The database already loaded stays in use. A
   client whose address the file does not hold counts as unknown.
 
-### Country lists
+### Country list
 
-Both are empty by default: the defaults judge a client by what it does, not by
-where it comes from.
+`SWW_EXCLUSIVELY_ALLOWED_COUNTRIES` is empty by default: the defaults judge a
+client by what it does, not by where it comes from. A `country=` tag in
+`SWW_TAG_DENY` refuses one country (see "Request tags").
 
-- `SWW_DENIED_COUNTRIES` refuses every request from a listed country.
 - `SWW_EXCLUSIVELY_ALLOWED_COUNTRIES` lets through only clients placed in a
   listed country. Every request from any other country is refused. So is every
   request from a client the lookup cannot place, such as internal monitoring or
@@ -510,45 +519,84 @@ where it comes from.
   client in whenever GeoJS stops answering. The cost: while GeoJS fails, this
   list refuses every new client. No other failure of GeoJS, a reputation source
   or an alert destination comes this close to taking the service down.
-- Both may be set. `SWW_DENIED_COUNTRIES` then adds nothing, since the exclusive
-  list already refuses every other country. A code on both lists stops the start
+- A code in this list whose `country=` tag is in `SWW_TAG_DENY` stops the start
   with a message naming it.
 - A refused request is answered with `SWW_BAN_RESPONSE`, as soon as the client's
   address has been looked up. It is logged with the action `country_denied`, and
   counted in the metrics.
 
+### Request tags
+
+Each request gets tags from what `discriminator` knows of its client and what
+the checks found. The operator refuses or slows clients by tag. Tags appear in
+the log line as `tags`, sorted, with empty lists left out (see
+`docs/request-log.md`).
+
+Each tag and where it comes from:
+
+- `asn=<number>` and `country=<code>`, such as `asn=64496` and `country=DE`,
+  from the lookup. A client the lookup cannot place has neither. A request
+  refused by `deny_nets` or `active_ban` has neither, because those checks come
+  before the lookup.
+- One tag per list of `SWW_TAG_LISTS` that holds the client (`tag_lists`), the
+  tag being the list's name, such as `torexit` or `vpn=mullvad`. These lists are
+  fetched and kept like a blocklist. `discriminator` ships none of its own.
+- `crowdsec`, `dnsbl=<zone>` and `abuseipdb`, when that reputation source lists
+  the client, whatever the source's action. A zone with a key is named with the
+  key masked, as the `reputation` field gives it.
+- `exploitsignature`, when a rule file or the Core Rule Set matched the request.
+  For the Core Rule Set a match is a score at or over
+  `SWW_WAF_ANOMALY_THRESHOLD`.
+
+A client in `SWW_ALLOW_NETS` skips the checks and gets no tag. Every tag is in
+lower case, except a country code, which is in capitals. `SWW_TAG_DENY` and
+`SWW_TAG_LIMIT_PERCENT` accept tags in either case.
+
+Two settings act on tags:
+
+- `SWW_TAG_DENY` lists tags whose requests are refused with the action `denied`
+  (`tag_deny`). The check runs twice: just before the rate limits, and again
+  after the Core Rule Set, so that `exploitsignature` can refuse too.
+- `SWW_TAG_LIMIT_PERCENT` lists tags with a percentage from 1 to 99. Their
+  clients get that percentage of every request and byte limit. The lowest
+  percentage among a client's tags applies. `exploitsignature` cannot be listed,
+  since a request gets it only after the rate limits have counted it.
+
+The tag settings are empty by default, for the same reason as the country list.
+The lookup waits for GeoJS when either names an `asn=` or `country=` tag. A
+setting that names one stops the start while `SWW_LOOKUP_SOURCE` is `off`.
+
 ### Biased thresholds
 
-The biased thresholds lower the limits of clients in listed AS numbers and
-countries. The lists are empty by default, for the same reason as the country
-lists. The request log and the metrics show which AS numbers and countries a
-service's abuse comes from.
+The biased thresholds lower the limits of clients by AS number, country and tag.
+The lists are empty by default, for the same reason as the country list. The
+request log and the metrics show which AS numbers and countries a service's
+abuse comes from.
 
-- Each list gives AS numbers or countries a percentage, such as `AS14061:50`.
-  Their clients get that percentage of every request and byte limit
-  (`SWW_ASN_LIMIT_PERCENT`, `SWW_COUNTRY_LIMIT_PERCENT`). A lowered limit is
-  rounded down. `0` is a zero allowance: the client's first request breaks a
-  limit and bans it.
+- `SWW_TAG_LIMIT_PERCENT` gives a tag a percentage, such as `asn=14061:50` (see
+  "Request tags"). A lowered limit is rounded down.
+- `SWW_UNKNOWN_LIMIT_PERCENT` at `0` is a zero allowance: the client's first
+  request breaks a limit and bans it.
 - `SWW_ASN_BYTES_PERCENT` and `SWW_COUNTRY_BYTES_PERCENT` set the byte limits'
   percentage alone, when it should differ from the request limits'. For an AS
-  number they list, they replace its percentage from `SWW_ASN_LIMIT_PERCENT` and
-  `SWW_ASN_LIMIT_PERCENT_URL`; for a country, the one from
-  `SWW_COUNTRY_LIMIT_PERCENT`.
+  number they list, they replace its `asn=` tag's percentage and its entry in
+  `SWW_ASN_LIMIT_PERCENT_URL`; for a country, its `country=` tag's percentage.
 - `SWW_ASN_LIMIT_PERCENT_URL` names a text file of `AS:percent` lines, so one
   abuse-source list can be shared by every `discriminator` in the fleet. It is
-  fetched and kept like a blocklist (see "Reputation"). Where it and
-  `SWW_ASN_LIMIT_PERCENT` both give a percentage, the lower applies.
+  fetched and kept like a blocklist (see "Reputation"). Each entry counts like
+  an `asn=` tag in `SWW_TAG_LIMIT_PERCENT`. Where both give a percentage, the
+  lower applies.
 - A client's limit percentage is the lowest of those that apply to it: its AS
-  number's, its country's, or a reputation hit's `limit:<percent>`. A client
-  without a country gets `SWW_UNKNOWN_LIMIT_PERCENT` in place of a country's.
-  The percentage is 100 if none applies. Clients given a lower percentage are
-  banned after fewer requests, first for a while and then, for repeated abuse,
-  permanently. The log line of each counted request, and the notes of each ban,
-  say which setting lowered the limit.
+  number's, its country's, its tags', or a reputation hit's `limit:<percent>`. A
+  client without a country gets `SWW_UNKNOWN_LIMIT_PERCENT` in place of a
+  country's. The percentage is 100 if none applies. Clients given a lower
+  percentage are banned after fewer requests, first for a while and then, for
+  repeated abuse, permanently. The log line of each counted request, and the
+  notes of each ban, say which setting lowered the limit.
 - No budget is shared by a whole country or AS number. One abuser could use it
   up and lock out everyone else there: a denial of service nobody chose, and the
   one this tool exists to prevent. Refusing a whole country is left to the
-  operator's choice, through the country lists.
+  operator's choice, through `SWW_TAG_DENY` or the country list.
 
 ### Attack detection
 
@@ -903,7 +951,7 @@ left unset sends no alert. An alert needs a destination only the operator can
 supply, and what counts as unusual depends on each service's normal traffic,
 which the metrics show. They reveal a widely distributed scraper, thousands of
 addresses at low rates each, which the per-client limits do not see. A low
-`SWW_ASN_LIMIT_PERCENT` for its AS number is the response.
+percentage for its `asn=` tag in `SWW_TAG_LIMIT_PERCENT` is the response.
 
 - Requests and bytes are counted per minute and per hour, for each of:
     - a client;
@@ -1181,7 +1229,7 @@ the metrics.
 
 ### The answer
 
-`discriminator` runs steps 3 to 13 of "What happens to a request", in that
+`discriminator` runs steps 3 to 16 of "What happens to a request", in that
 order. Every answer but the last below carries `X-Sww-Disposition`.
 
 - `X-Sww-Disposition: allow`, status `200`, no body. `rproxy` passes the request
@@ -1220,13 +1268,13 @@ seconds, and `SWRP_DEFAULT_DISPOSITION` then decides. So at the defaults,
 and whatever its outside sources do.
 
 GeoJS is the only outside source a question can wait on. A question waits only
-when step 5 says so, and for at most `SWW_LOOKUP_TIMEOUT`, by default 800
+when step 6 says so, and for at most `SWW_LOOKUP_TIMEOUT`, by default 800
 milliseconds. A client without an answer by then counts as unknown. No question
 waits on these, which run in the background:
 
 - the DNS blocklists and AbuseIPDB;
-- fetching the blocklists, the CrowdSec decision list and the file
-  `SWW_ASN_LIMIT_PERCENT_URL` names.
+- fetching the blocklists, the tag lists, the CrowdSec decision list and the
+  file `SWW_ASN_LIMIT_PERCENT_URL` names.
 
 In `enforce` mode, a question does not wait for GeoJS when it is a request:
 

docs/request-log.md

@@ -96,8 +96,8 @@ Every one of these lines has:
 
 - `action`: what was done:
     - `forward`: answered `allow`, so that `rproxy` passes it to the app;
-    - `denied`: refused for `SWW_DENY_NETS`, or for a reputation source with the
-      action `deny`;
+    - `denied`: refused for `SWW_DENY_NETS`, for a reputation source with the
+      action `deny`, or for a tag in `SWW_TAG_DENY`;
     - `banned`: refused under a ban, or for a `ban` rule, a trap path or a
       CrowdSec decision, each of which bans the client;
     - `country_denied`, `rate_limited`, `rule_blocked` and `waf_blocked`:
@@ -115,6 +115,7 @@ Every one of these lines has:
     - `deny_nets`: `netblock`, the entry of `SWW_DENY_NETS` the client is in;
     - `active_ban`: `netblock`, the ban's netblock, and `ban_expires`;
     - `countries`: `country`, and `setting`, the country list that refused it;
+    - `tag_deny`: `tag`, the tag of `SWW_TAG_DENY` the request carries;
     - `blocklists`: `lists`, the blocklist URLs that list the client;
     - `crowdsec`: `scenario`, the decision's scenario, and `expires`, when the
       decision ends;
@@ -168,6 +169,8 @@ Every one of these lines has:
     - the CrowdSec decision list's URL;
     - DNS blocklist zones;
     - `abuseipdb`.
+- `tags`: the request's tags, sorted, left out when it has none. Each tag and
+  where it comes from is under "Request tags" in [`SPEC.md`](../SPEC.md).
 - `offence`: `limit`, for a request that broke a limit.
 - `ban_expires`: when the client's ban ends, for a request that made one or was
   refused under one: a time, or `permanent`.

docs/settings.md

@@ -90,11 +90,11 @@ between the two (see "The image's command" below).
 ## Static lists
 
 - `SWW_ALLOW_NETS` (default empty): netblocks you trust, such as your monitoring
-  (see step 3 in [`SPEC.md`](../SPEC.md)).
+  (see step 4 in [`SPEC.md`](../SPEC.md)).
 - `SWW_RATE_LIMIT_EXEMPT_NETS` (default empty): netblocks whose clients are
   exempt from rate limiting and the byte limits.
 - `SWW_DENY_NETS` (default empty): netblocks whose clients are refused (see step
-  3 in [`SPEC.md`](../SPEC.md)).
+  4 in [`SPEC.md`](../SPEC.md)).
 
 ## Request rate limits, per client
 
@@ -130,9 +130,11 @@ between the two (see "The image's command" below).
 
 - `SWW_LOOKUP_SOURCE` (default `geojs`): `geojs`, `file` or `off`. `off` stops
   the start while a setting that needs a lookup is set:
-    - the two country lists;
+    - `SWW_EXCLUSIVELY_ALLOWED_COUNTRIES`;
     - `SWW_ADD_LOOKUP_HEADERS`;
-    - the four biased threshold lists and `SWW_ASN_LIMIT_PERCENT_URL`;
+    - `SWW_TAG_DENY` or `SWW_TAG_LIMIT_PERCENT` naming an `asn=` or `country=`
+      tag;
+    - the two byte percentage lists and `SWW_ASN_LIMIT_PERCENT_URL`;
     - `SWW_UNKNOWN_LIMIT_PERCENT` below `100`;
     - an anomaly threshold per AS number.
 - `SWW_LOOKUP_DB_PATH` (default empty): the IPinfo Lite database file, in its
@@ -144,28 +146,61 @@ between the two (see "The image's command" below).
   the client's AS number in `X-Client-ASN` and its country in
   `X-Client-Country`.
 
-## Country lists
+## Country list
 
-- `SWW_DENIED_COUNTRIES` (default empty): countries whose clients are refused,
-  such as `cn,ru,kp`.
 - `SWW_EXCLUSIVELY_ALLOWED_COUNTRIES` (default empty): when set, the only
-  countries whose clients get through, such as `us,de`. A country on both lists
-  stops the start.
+  countries whose clients get through, such as `us,de`. A country whose
+  `country=` tag is in `SWW_TAG_DENY` stops the start.
+
+## Request tags
+
+Every request gets tags from what `discriminator` knows of its client. See
+"Request tags" in [`SPEC.md`](../SPEC.md).
+
+- `SWW_TAG_LISTS` (default empty): address lists that each add a tag, as
+  `name=URL` pairs, such as `torexit=https://example.com/tor.txt`. A name is the
+  tag, and may hold `=`, such as `vpn=mullvad`. Each list is an `http` or
+  `https` URL fetched like a blocklist. A name or URL listed twice is refused.
+  So is a URL that is also in `SWW_BLOCKLIST_URLS`, `SWW_ASN_LIMIT_PERCENT_URL`,
+  or the CrowdSec decision list.
+- `SWW_TAG_DENY` (default empty): tags whose requests are refused, such as
+  `torexit,country=CN`. A tag listed twice, an `asn=` tag without a number, or a
+  `country=` tag without a country, is refused.
+- `SWW_TAG_LIMIT_PERCENT` (default empty): tags that lower a client's limits, as
+  tag and percentage pairs, such as `vpn:50,asn=14061:25`. A percentage is from
+  `1` to `99`, of every rate limit and byte limit. The lowest percentage among a
+  client's tags applies. A tag listed twice is refused. So is
+  `exploitsignature`: a request gets that tag after the rate limits have counted
+  it.
+
+`SWW_TAG_DENY` and `SWW_TAG_LIMIT_PERCENT` accept tags in either case. A tag
+that no request can get stops the start. A request can get only these:
+
+- a name in `SWW_TAG_LISTS`;
+- an `asn=` or `country=` tag;
+- a `dnsbl=` tag of a zone in `SWW_DNSBL_ZONES`, in lower case, with a key
+  masked as the `reputation` field shows it;
+- `abuseipdb`, while `SWW_ABUSEIPDB_KEY` is set;
+- `exploitsignature`, in `SWW_TAG_DENY` only, while `SWW_RULES_ENABLED` is
+  `true`, or while neither `SWW_WAF_MODE` nor `SWW_WAF_ANOMALY_THRESHOLD` is
+  `off`.
+
+`crowdsec` stops the start in both settings, because a CrowdSec decision refuses
+the request first.
 
 ## Biased thresholds
 
-- `SWW_ASN_LIMIT_PERCENT` (default empty): a list of AS numbers, each with `:`
-  and a percentage, such as `AS14061:50,AS16276:50,AS45102:25`. An AS number
-  listed twice is refused.
-- `SWW_COUNTRY_LIMIT_PERCENT` (default empty): the same by country, such as
-  `cn:25,ru:50`.
-- `SWW_ASN_BYTES_PERCENT` and `SWW_COUNTRY_BYTES_PERCENT` (default empty): the
-  same, for the byte limits alone.
+- `SWW_ASN_BYTES_PERCENT` and `SWW_COUNTRY_BYTES_PERCENT` (default empty): a
+  percentage of the byte limits alone, for the AS numbers or countries listed,
+  such as `AS14061:50` or `cn:25`. It takes the place of the percentage
+  `SWW_TAG_LIMIT_PERCENT` gives their `asn=` or `country=` tag. An AS number or
+  country listed twice is refused.
 - `SWW_UNKNOWN_LIMIT_PERCENT` (default `100`): the percentage for a client the
   lookup cannot place.
 - `SWW_ASN_LIMIT_PERCENT_URL` (default unset): the `http` or `https` URL of a
   text file with one AS number and percentage on each line, such as
-  `AS64496:50`. A URL that is also in `SWW_BLOCKLIST_URLS` is refused.
+  `AS64496:50`. Each entry counts like an `asn=` tag in `SWW_TAG_LIMIT_PERCENT`.
+  A URL that is also in `SWW_BLOCKLIST_URLS` is refused.
 
 ## Attack detection
 

internal/config/config.go

@@ -93,29 +93,30 @@ type Config struct {
 	LookupDBPath     string
 	LookupTimeout    time.Duration
 	AddLookupHeaders bool
-	// DeniedCountries are the countries whose clients are refused
-	// (SWW_DENIED_COUNTRIES). ExclusivelyAllowedCountries, when not
-	// empty, are the only countries whose clients are let through
-	// (SWW_EXCLUSIVELY_ALLOWED_COUNTRIES). Both hold two-letter codes in
-	// capitals, as GeoJS gives them.
-	DeniedCountries             []string
+	// ExclusivelyAllowedCountries, when not empty, are the only countries
+	// whose clients are let through (SWW_EXCLUSIVELY_ALLOWED_COUNTRIES),
+	// two-letter codes in capitals, as GeoJS gives them.
 	ExclusivelyAllowedCountries []string
-	// The biased thresholds. ASNLimitPercent and CountryLimitPercent give
-	// the clients of the AS numbers and the countries they list that
-	// percentage of every rate limit and byte limit
-	// (SWW_ASN_LIMIT_PERCENT and SWW_COUNTRY_LIMIT_PERCENT).
-	// ASNBytesPercent and CountryBytesPercent give those they list a
-	// percentage of the byte limits in place of that one
+	// TagLists are the address lists that each add a tag to the requests of
+	// the clients they hold (SWW_TAG_LISTS). TagDeny are the tags whose
+	// requests are refused (SWW_TAG_DENY). TagLimitPercent gives the clients
+	// with a tag that percentage of every rate limit and byte limit, from 1
+	// to 99 (SWW_TAG_LIMIT_PERCENT). All hold tags as requests carry them: in
+	// lower case, a country code in capitals.
+	TagLists        []TagList
+	TagDeny         []string
+	TagLimitPercent map[string]int64
+	// The biased thresholds. ASNBytesPercent and CountryBytesPercent give
+	// those they list a percentage of the byte limits in place of the one
+	// TagLimitPercent gives their asn= or country= tag
 	// (SWW_ASN_BYTES_PERCENT and SWW_COUNTRY_BYTES_PERCENT). Each holds
 	// percentages from 0 to 100, by AS number, written as AS64496, or by
 	// country, a two-letter code in capitals, as the lookup gives them.
 	// UnknownLimitPercent is the percentage of every limit a client without
 	// a country gets (SWW_UNKNOWN_LIMIT_PERCENT). ASNLimitPercentURL is
 	// where a file of AS:percent lines is fetched from, whose percentages
-	// count as those of ASNLimitPercent do (SWW_ASN_LIMIT_PERCENT_URL), ""
-	// while it is unset.
-	ASNLimitPercent     map[string]int64
-	CountryLimitPercent map[string]int64
+	// count like asn= tags in TagLimitPercent (SWW_ASN_LIMIT_PERCENT_URL),
+	// "" while it is unset.
 	ASNBytesPercent     map[string]int64
 	CountryBytesPercent map[string]int64
 	UnknownLimitPercent int64
@@ -164,8 +165,8 @@ type Config struct {
 	// BanResponse is the status a refused client is answered with, 403
 	// or 429, or 0 to close the connection without an answer
 	// (SWW_BAN_RESPONSE). It answers a banned client, a request that
-	// breaks a rate limit or matches a ban rule, SWW_DENY_NETS and the
-	// country lists.
+	// breaks a rate limit or matches a ban rule, SWW_DENY_NETS,
+	// SWW_EXCLUSIVELY_ALLOWED_COUNTRIES and SWW_TAG_DENY.
 	BanResponse int
 	// LimitBanDuration is the ban for a first broken rate limit
 	// (SWW_LIMIT_BAN_DURATION). A limit broken again within
@@ -367,7 +368,7 @@ var (
 	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 SWW_DENIED_COUNTRIES too")
+	errOnBothLists     = errors.New("is in SWW_TAG_DENY too")
 	errNotLookupSource = errors.New("is not geojs, file or off")
 	errNeedsLookups    = errors.New("it needs each client looked up")
 	errNeedsDBPath     = errors.New("it names the file to look clients up in")
@@ -465,6 +466,25 @@ var (
 	errLAPIKeyUnused = errors.New("it is sent only to the engine at that URL")
 	errAnotherList   = errors.New(
 		"is in SWW_BLOCKLIST_URLS or is SWW_ASN_LIMIT_PERCENT_URL too")
+	errFetchedOtherwise = errors.New("is in SWW_BLOCKLIST_URLS, is " +
+		"SWW_ASN_LIMIT_PERCENT_URL or is the CrowdSec decision list too")
+	errNotTagList = errors.New(
+		"is not a name, = and an http or https URL, such as " +
+			"torexit=https://example.com/tor.txt")
+	errNotTagPercentItem = errors.New(
+		"is not a tag, : and a percentage, such as vpn:50 or asn=14061:25")
+	errNotTagPercent = errors.New("is not a percentage from 1 to 99")
+	errNotASNTag     = errors.New("is not asn= and a number, such as asn=14061")
+	errExploitTag    = errors.New(
+		"cannot lower limits: the rate limits count a request before its " +
+			"rules are matched")
+	errCrowdSecTag = errors.New(
+		"cannot be used: a CrowdSec decision refuses the request first")
+	errNoRequestGetsTag = errors.New(
+		"is a tag no request can get: it is not a name in SWW_TAG_LISTS, an " +
+			"asn= or country= tag, a dnsbl= tag of a zone in SWW_DNSBL_ZONES, " +
+			"abuseipdb with SWW_ABUSEIPDB_KEY set, or exploitsignature with " +
+			"rule files or the Core Rule Set on")
 )
 
 // FromEnvironment reads the settings with lookupEnv, normally
@@ -499,11 +519,11 @@ func FromEnvironment(
 		LookupDBPath:         env.value("SWW_LOOKUP_DB_PATH", ""),
 		LookupTimeout:        env.durationNotOff("SWW_LOOKUP_TIMEOUT", "800ms"),
 		AddLookupHeaders:     env.boolean("SWW_ADD_LOOKUP_HEADERS", "false"),
-		DeniedCountries:      env.countries("SWW_DENIED_COUNTRIES", ""),
 		ExclusivelyAllowedCountries: env.countries(
 			"SWW_EXCLUSIVELY_ALLOWED_COUNTRIES", ""),
-		ASNLimitPercent:      env.percents("SWW_ASN_LIMIT_PERCENT", ParseASN),
-		CountryLimitPercent:  env.percents("SWW_COUNTRY_LIMIT_PERCENT", parseCountry),
+		TagLists:             env.tagLists("SWW_TAG_LISTS"),
+		TagDeny:              env.tags("SWW_TAG_DENY"),
+		TagLimitPercent:      env.tagPercents("SWW_TAG_LIMIT_PERCENT"),
 		ASNBytesPercent:      env.percents("SWW_ASN_BYTES_PERCENT", ParseASN),
 		CountryBytesPercent:  env.percents("SWW_COUNTRY_BYTES_PERCENT", parseCountry),
 		UnknownLimitPercent:  env.percent("SWW_UNKNOWN_LIMIT_PERCENT", "100"),
@@ -583,6 +603,8 @@ func FromEnvironment(
 	env.checkCountriesAndLookups(cfg)
 	env.checkASNLimitPercentURL(cfg)
 	env.checkCrowdSec(cfg)
+	env.checkTagLists(cfg)
+	env.checkTags(cfg)
 
 	if env.err != nil {
 		return nil, env.err
@@ -860,6 +882,31 @@ func (e *environment) percents(
 	return percents
 }
 
+// tagLists reads SWW_TAG_LISTS, which is empty by default.
+func (e *environment) tagLists(name string) []TagList {
+	lists, err := parseTagLists(e.value(name, ""))
+	e.check(name, err)
+
+	return lists
+}
+
+// tags reads a setting that is a list of tags. It is empty by default.
+func (e *environment) tags(name string) []string {
+	tags, err := parseTags(e.value(name, ""))
+	e.check(name, err)
+
+	return tags
+}
+
+// tagPercents reads a setting that is a list of tags, each with a
+// percentage. It is empty by default.
+func (e *environment) tagPercents(name string) map[string]int64 {
+	percents, err := parseTagPercents(e.value(name, ""))
+	e.check(name, err)
+
+	return percents
+}
+
 // percent reads a setting that is a percentage, from 0 to 100.
 func (e *environment) percent(name, defaultValue string) int64 {
 	percent, err := ParsePercent(e.value(name, defaultValue))
@@ -997,15 +1044,17 @@ func (e *environment) checkLookupDBPath(cfg *Config) {
 	}
 }
 
-// checkCountriesAndLookups refuses a country on both country lists, and,
+// checkCountriesAndLookups refuses a country in
+// SWW_EXCLUSIVELY_ALLOWED_COUNTRIES whose tag is in SWW_TAG_DENY, and,
 // while SWW_LOOKUP_SOURCE is off, each setting that needs clients looked
-// up: the country lists, SWW_ADD_LOOKUP_HEADERS, the biased thresholds,
+// up: the country list, SWW_ADD_LOOKUP_HEADERS, the tag settings that name
+// an asn= or country= tag, the biased thresholds,
 // SWW_ASN_LIMIT_PERCENT_URL among them, of which
 // SWW_UNKNOWN_LIMIT_PERCENT needs them only below 100, where it lowers a
 // limit, and the anomaly thresholds per AS number.
 func (e *environment) checkCountriesAndLookups(cfg *Config) {
 	for _, country := range cfg.ExclusivelyAllowedCountries {
-		if slices.Contains(cfg.DeniedCountries, country) {
+		if slices.Contains(cfg.TagDeny, CountryTagPrefix+country) {
 			e.check("SWW_EXCLUSIVELY_ALLOWED_COUNTRIES",
 				fmt.Errorf("%q %w", country, errOnBothLists))
 		}
@@ -1019,11 +1068,10 @@ func (e *environment) checkCountriesAndLookups(cfg *Config) {
 		name string
 		set  bool
 	}{
-		{"SWW_DENIED_COUNTRIES", len(cfg.DeniedCountries) > 0},
 		{"SWW_EXCLUSIVELY_ALLOWED_COUNTRIES", len(cfg.ExclusivelyAllowedCountries) > 0},
 		{"SWW_ADD_LOOKUP_HEADERS", cfg.AddLookupHeaders},
-		{"SWW_ASN_LIMIT_PERCENT", len(cfg.ASNLimitPercent) > 0},
-		{"SWW_COUNTRY_LIMIT_PERCENT", len(cfg.CountryLimitPercent) > 0},
+		{"SWW_TAG_DENY", slices.ContainsFunc(cfg.TagDeny, isLookupTag)},
+		{"SWW_TAG_LIMIT_PERCENT", tagLimitNeedsLookups(cfg)},
 		{"SWW_ASN_BYTES_PERCENT", len(cfg.ASNBytesPercent) > 0},
 		{"SWW_COUNTRY_BYTES_PERCENT", len(cfg.CountryBytesPercent) > 0},
 		{"SWW_UNKNOWN_LIMIT_PERCENT", cfg.UnknownLimitPercent < 100},
@@ -1069,6 +1117,90 @@ func (e *environment) checkCrowdSec(cfg *Config) {
 	}
 }
 
+// checkTagLists refuses a list of SWW_TAG_LISTS whose URL is fetched as
+// another list too: the file at a URL is read as one kind of list.
+func (e *environment) checkTagLists(cfg *Config) {
+	for _, list := range cfg.TagLists {
+		if slices.Contains(cfg.BlocklistURLs, list.URL) ||
+			list.URL == cfg.ASNLimitPercentURL || list.URL == cfg.CrowdSecDecisionsURL {
+			e.check("SWW_TAG_LISTS", fmt.Errorf("%q %w", list.URL, errFetchedOtherwise))
+		}
+	}
+}
+
+// checkTags refuses a tag of SWW_TAG_DENY or SWW_TAG_LIMIT_PERCENT that would
+// never apply: crowdsec, whose request is refused before tags are acted on, and
+// any tag these settings cannot give a request.
+func (e *environment) checkTags(cfg *Config) {
+	for _, tag := range cfg.TagDeny {
+		e.check("SWW_TAG_DENY", checkTag(cfg, tag))
+	}
+
+	for tag := range cfg.TagLimitPercent {
+		e.check("SWW_TAG_LIMIT_PERCENT", checkTag(cfg, tag))
+	}
+}
+
+// checkTag returns an error when tag would never apply, as checkTags says.
+func checkTag(cfg *Config, tag string) error {
+	if tag == CrowdSecTag {
+		return fmt.Errorf("%q %w", tag, errCrowdSecTag)
+	}
+
+	if !requestCanGetTag(cfg, tag) {
+		return fmt.Errorf("%q %w", MaskZoneKey(tag), errNoRequestGetsTag)
+	}
+
+	return nil
+}
+
+// requestCanGetTag reports whether anything cfg sets up can give a request tag.
+func requestCanGetTag(cfg *Config, tag string) bool {
+	isListName := func(list TagList) bool { return list.Name == tag }
+	if isLookupTag(tag) || slices.ContainsFunc(cfg.TagLists, isListName) {
+		return true
+	}
+
+	if tag == ExploitSignatureTag {
+		coreRuleSetOn := cfg.WAFMode != WAFModeOff && cfg.WAFAnomalyThreshold != 0
+
+		return cfg.RulesEnabled || coreRuleSetOn
+	}
+
+	if tag == AbuseIPDBTag {
+		return cfg.AbuseIPDBKey != ""
+	}
+
+	zone, isZoneTag := strings.CutPrefix(tag, DNSBLTagPrefix)
+
+	return isZoneTag && slices.ContainsFunc(cfg.DNSBLZones, func(each string) bool {
+		return strings.ToLower(MaskZoneKey(each)) == zone
+	})
+}
+
+// TagsNeedLookup reports whether SWW_TAG_DENY or SWW_TAG_LIMIT_PERCENT
+// names an asn= or country= tag, which only the lookup can give a request.
+func (c *Config) TagsNeedLookup() bool {
+	return slices.ContainsFunc(c.TagDeny, isLookupTag) || tagLimitNeedsLookups(c)
+}
+
+// tagLimitNeedsLookups reports whether SWW_TAG_LIMIT_PERCENT names an asn=
+// or country= tag.
+func tagLimitNeedsLookups(cfg *Config) bool {
+	for tag := range cfg.TagLimitPercent {
+		if isLookupTag(tag) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// isLookupTag reports whether tag is an asn= or country= tag.
+func isLookupTag(tag string) bool {
+	return strings.HasPrefix(tag, ASNTagPrefix) || strings.HasPrefix(tag, CountryTagPrefix)
+}
+
 // 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 {
@@ -1785,6 +1917,161 @@ func ParseASN(value string) (string, error) {
 	return "AS" + strconv.FormatUint(number, 10), nil
 }
 
+// The tags a request can get that the settings can name, as discriminator
+// writes them. The prefixes are followed by a value.
+const (
+	ASNTagPrefix     = "asn="
+	CountryTagPrefix = "country="
+	DNSBLTagPrefix   = "dnsbl="
+	AbuseIPDBTag     = "abuseipdb"
+	CrowdSecTag      = "crowdsec"
+	// ExploitSignatureTag is the tag of a request a rule file or the Core
+	// Rule Set matched.
+	ExploitSignatureTag = "exploitsignature"
+)
+
+// TagList is an address list of SWW_TAG_LISTS: the tag it adds to the
+// requests of the clients it holds, and the URL it is fetched from.
+type TagList struct {
+	Name string
+	URL  string
+}
+
+// parseTagLists reads a comma-separated list of name=URL pairs, such as
+// torexit=https://example.com/tor.txt, and returns each list with its name
+// in lower case. A name can hold a =, as vpn=mullvad does, and ends at the
+// = before http. A name or a URL listed twice is an error.
+func parseTagLists(value string) ([]TagList, error) {
+	items, err := parseList(value)
+	if err != nil {
+		return nil, err
+	}
+
+	lists := make([]TagList, 0, len(items))
+
+	for _, item := range items {
+		end := strings.Index(item, "=http")
+		if end <= 0 || !isListURL(item[end+1:]) {
+			return nil, fmt.Errorf("%q %w", item, errNotTagList)
+		}
+
+		list := TagList{Name: strings.ToLower(item[:end]), URL: item[end+1:]}
+
+		if slices.ContainsFunc(lists, func(earlier TagList) bool {
+			return earlier.Name == list.Name || earlier.URL == list.URL
+		}) {
+			return nil, fmt.Errorf("%q %w", item, errListedTwice)
+		}
+
+		lists = append(lists, list)
+	}
+
+	return lists, nil
+}
+
+// parseTags reads a comma-separated list of tags, which parseTag reads. A
+// tag listed twice is an error, which shows the tag as MaskZoneKey does.
+func parseTags(value string) ([]string, error) {
+	items, err := parseList(value)
+	if err != nil {
+		// parseList's error, for an empty item, shows the whole value, keys
+		// included.
+		return nil, errEmptyItem
+	}
+
+	tags := make([]string, 0, len(items))
+
+	for _, item := range items {
+		tag, err := parseTag(item)
+		if err != nil {
+			return nil, err
+		}
+
+		if slices.Contains(tags, tag) {
+			return nil, fmt.Errorf("%q %w", MaskZoneKey(item), errListedTwice)
+		}
+
+		tags = append(tags, tag)
+	}
+
+	return tags, nil
+}
+
+// parseTag reads a tag in either case, with spaces around it, and returns it
+// as a request carries it: in lower case, but for a country code, which is in
+// capitals, and an asn= tag's number without leading zeros. An asn= or
+// country= tag must name a number or a country, so that a mistyped one stops
+// the start instead of never matching.
+func parseTag(value string) (string, error) {
+	tag := strings.ToLower(strings.TrimSpace(value))
+
+	if digits, isASN := strings.CutPrefix(tag, ASNTagPrefix); isASN {
+		number, err := strconv.ParseUint(digits, 10, 32)
+		if err != nil {
+			return "", fmt.Errorf("%q %w", value, errNotASNTag)
+		}
+
+		return ASNTagPrefix + strconv.FormatUint(number, 10), nil
+	}
+
+	if code, isCountry := strings.CutPrefix(tag, CountryTagPrefix); isCountry {
+		country, err := parseCountry(code)
+		if err != nil {
+			return "", err
+		}
+
+		return CountryTagPrefix + country, nil
+	}
+
+	return tag, nil
+}
+
+// parseTagPercents reads a comma-separated list of tags, each with : and a
+// percentage from 1 to 99, such as vpn:50 or asn=14061:25. A tag listed
+// twice is an error, and so is ExploitSignatureTag, which a request gets
+// only after the rate limits have counted it.
+func parseTagPercents(value string) (map[string]int64, error) {
+	items, err := parseList(value)
+	if err != nil {
+		// parseList's error, for an empty item, shows the whole value, keys
+		// included.
+		return nil, errEmptyItem
+	}
+
+	percents := make(map[string]int64, len(items))
+
+	for _, item := range items {
+		colon := strings.LastIndex(item, ":")
+		if colon <= 0 {
+			return nil, fmt.Errorf("%q %w", MaskZoneKey(item), errNotTagPercentItem)
+		}
+
+		tag, err := parseTag(item[:colon])
+		if err != nil {
+			return nil, err
+		}
+
+		percent, err := strconv.ParseInt(item[colon+1:], 10, 64)
+		if err != nil || percent < 1 || percent > 99 {
+			return nil, fmt.Errorf("%q %w", item[colon+1:], errNotTagPercent)
+		}
+
+		if tag == ExploitSignatureTag {
+			return nil, fmt.Errorf("%q %w", tag, errExploitTag)
+		}
+
+		if _, listed := percents[tag]; listed {
+			// tag, since item[:colon] may end in a space, which MaskZoneKey
+			// would not mask.
+			return nil, fmt.Errorf("%q %w", MaskZoneKey(tag), errListedTwice)
+		}
+
+		percents[tag] = percent
+	}
+
+	return percents, nil
+}
+
 // parsePercents reads a comma-separated list of items, each an AS number
 // or a country, which parseCode reads, then : and a percentage, such as
 // AS64496:50 or cn:25, and returns each one's percentage. An empty value

internal/config/config_test.go

@@ -42,10 +42,10 @@ const (
 	lookupDBPath         = "SWW_LOOKUP_DB_PATH"
 	lookupTimeout        = "SWW_LOOKUP_TIMEOUT"
 	addLookupHeaders     = "SWW_ADD_LOOKUP_HEADERS"
-	deniedCountries      = "SWW_DENIED_COUNTRIES"
 	allowedCountries     = "SWW_EXCLUSIVELY_ALLOWED_COUNTRIES"
-	asnLimitPercent      = "SWW_ASN_LIMIT_PERCENT"
-	countryLimitPercent  = "SWW_COUNTRY_LIMIT_PERCENT"
+	tagLists             = "SWW_TAG_LISTS"
+	tagDeny              = "SWW_TAG_DENY"
+	tagLimitPercent      = "SWW_TAG_LIMIT_PERCENT"
 	asnBytesPercent      = "SWW_ASN_BYTES_PERCENT"
 	countryBytesPercent  = "SWW_COUNTRY_BYTES_PERCENT"
 	unknownLimitPercent  = "SWW_UNKNOWN_LIMIT_PERCENT"
@@ -208,6 +208,9 @@ const off = "off"
 // enabled is true, as a setting's value.
 const enabled = "true"
 
+// disabled is false, as a setting's value.
+const disabled = "false"
+
 // defaultLookupSource is the default of SWW_LOOKUP_SOURCE, and
 // fileSource the source that is the lookup database.
 const (
@@ -274,9 +277,13 @@ func TestDefaults(t *testing.T) {
 	wantNetblocks(t, cfg.AllowNets)
 	wantNetblocks(t, cfg.RateLimitExemptNets)
 	wantNetblocks(t, cfg.DenyNets)
-	wantCountries(t, deniedCountries, cfg.DeniedCountries)
 	wantCountries(t, allowedCountries, cfg.ExclusivelyAllowedCountries)
 
+	if len(cfg.TagLists) != 0 || len(cfg.TagDeny) != 0 || len(cfg.TagLimitPercent) != 0 {
+		t.Errorf("tag settings %v, %v and %v by default, want all empty",
+			cfg.TagLists, cfg.TagDeny, cfg.TagLimitPercent)
+	}
+
 	hostname, err := os.Hostname()
 	if err != nil || hostname == "" || cfg.InstanceName != hostname {
 		t.Errorf("%s is %q, want the host's name %q (%v)", instanceName,
@@ -327,7 +334,6 @@ func TestValuesAsSet(t *testing.T) {
 		rateLimitPerMinute:   "60",
 		rateLimitPerHour:     "600",
 		rateLimitPerDay:      "6000",
-		deniedCountries:      "cn, RU,kp,Xk",
 		allowedCountries:     "de",
 		banResponse:          "429",
 		limitBanDuration:     "15m",
@@ -342,7 +348,7 @@ func TestValuesAsSet(t *testing.T) {
 		metricsToken:         token,
 		metricsTopN:          "10",
 		rulesDir:             "/srv/waf-rules",
-		rulesEnabled:         "false",
+		rulesEnabled:         disabled,
 	})
 
 	wantSettings(t, cfg, config.Config{
@@ -370,7 +376,6 @@ func TestValuesAsSet(t *testing.T) {
 	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")
 }
 
@@ -1097,15 +1102,15 @@ func TestInstanceNameNotUTF8StopsTheStart(t *testing.T) {
 	}
 }
 
-func TestCodeOnBothCountryListsStopsTheStart(t *testing.T) {
+func TestCodeInAllowedCountriesAndTagDenyStopsTheStart(t *testing.T) {
 	t.Parallel()
 
 	_, err := config.FromEnvironment(environment{
-		deniedCountries:  "cn,ru",
+		tagDeny:          "country=cn,country=ru",
 		allowedCountries: "de,RU",
 	}.lookupEnv)
 	if err == nil {
-		t.Fatal("ru on both country lists was accepted")
+		t.Fatal("ru in SWW_EXCLUSIVELY_ALLOWED_COUNTRIES and SWW_TAG_DENY was accepted")
 	}
 
 	if !strings.HasPrefix(err.Error(), allowedCountries+": ") ||
@@ -1176,12 +1181,11 @@ func TestSettingNeedingLookupsStopsTheStartWhileTheyAreOff(t *testing.T) {
 	t.Parallel()
 
 	for name, value := range map[string]string{
-		deniedCountries:                "kp",
 		allowedCountries:               "de",
 		addLookupHeaders:               enabled,
+		tagDeny:                        "country=KP",
+		tagLimitPercent:                "asn=64496:50",
 		asnLimitPercentURL:             asnURL,
-		asnLimitPercent:                "AS64496:50",
-		countryLimitPercent:            "cn:25",
 		asnBytesPercent:                "AS64496:50",
 		countryBytesPercent:            "cn:25",
 		unknownLimitPercent:            "99",
@@ -1204,12 +1208,13 @@ func TestSettingNeedingLookupsStopsTheStartWhileTheyAreOff(t *testing.T) {
 	}
 
 	// Set empty, the lists need nothing looked up, and nor does
-	// SWW_UNKNOWN_LIMIT_PERCENT at 100, which lowers no limit, an anomaly
-	// threshold per AS number that is off, any other anomaly threshold, or
-	// a blocklist.
+	// SWW_UNKNOWN_LIMIT_PERCENT at 100, which lowers no limit, a tag the
+	// lookup does not give, an anomaly threshold per AS number that is off,
+	// any other anomaly threshold, or a blocklist.
 	env := environment{
-		lookupSource: off, deniedCountries: "", allowedCountries: "",
-		asnLimitPercent: "", countryLimitPercent: "", asnBytesPercent: "",
+		lookupSource: off, allowedCountries: "", asnBytesPercent: "",
+		tagLists: "torexit=https://example.com/tor.txt,vpn=https://example.com/vpn.txt",
+		tagDeny:  torExitTag, tagLimitPercent: "vpn:50",
 		countryBytesPercent: "", unknownLimitPercent: "100", asnLimitPercentURL: "",
 		blocklistURLs: dropURL,
 	}
@@ -1355,34 +1360,190 @@ func TestInvalidAnomalySettingStopsTheStartSayingWhatIsWrong(t *testing.T) {
 	}
 }
 
+// torExitTag, zenTag and exploitTag are tags these tests name.
+const (
+	torExitTag = "torexit"
+	zenTag     = "dnsbl=zen.example"
+	exploitTag = "exploitsignature"
+)
+
+func TestTagSettingsAsSet(t *testing.T) {
+	t.Parallel()
+
+	const torURL = "https://example.com/tor.txt"
+
+	// Names and tags in either case, an AS number with leading zeros, and a
+	// name holding a =.
+	cfg := fromEnvironment(t, environment{
+		tagLists: "TorExit=" + torURL +
+			", vpn=mullvad=https://example.com/mullvad.txt",
+		dnsblZones:      "Zen.example",
+		tagDeny:         "TorExit, Country=kp, asn=014061",
+		tagLimitPercent: "vpn=mullvad :50, asn=014061:25, COUNTRY=cn:1, dnsbl=zen.example:99",
+	})
+
+	wantLists := []config.TagList{
+		{Name: torExitTag, URL: torURL},
+		{Name: "vpn=mullvad", URL: "https://example.com/mullvad.txt"},
+	}
+	if !slices.Equal(cfg.TagLists, wantLists) {
+		t.Errorf("%s gave %+v, want %+v", tagLists, cfg.TagLists, wantLists)
+	}
+
+	wantDeny := []string{torExitTag, "country=KP", "asn=14061"}
+	if !slices.Equal(cfg.TagDeny, wantDeny) {
+		t.Errorf("%s gave %v, want %v", tagDeny, cfg.TagDeny, wantDeny)
+	}
+
+	wantPercents := map[string]int64{
+		"vpn=mullvad": 50, "asn=14061": 25, "country=CN": 1, zenTag: 99,
+	}
+	if !maps.Equal(cfg.TagLimitPercent, wantPercents) {
+		t.Errorf("%s gave %v, want %v", tagLimitPercent, cfg.TagLimitPercent, wantPercents)
+	}
+}
+
+func TestTagThatNoRequestCanGetIsToldApartFromOneItCan(t *testing.T) {
+	t.Parallel()
+
+	const (
+		list   = "torexit=https://example.com/tor.txt"
+		key    = "abc123"
+		zone   = key + ".xbl.dq.spamhaus.net"
+		masked = "********.xbl.dq.spamhaus.net"
+	)
+
+	for _, tc := range []struct {
+		name string
+		env  environment
+		want string // "" is accepted
+	}{
+		{"a list's name", environment{tagLists: list, tagDeny: torExitTag}, ""},
+		{
+			"a mistyped list's name", environment{tagLists: list, tagDeny: "torexti"},
+			`"torexti"`,
+		},
+		{"a masked zone", environment{dnsblZones: zone, tagDeny: "dnsbl=" + masked}, ""},
+		{
+			"a zone with its key", environment{dnsblZones: zone, tagDeny: "dnsbl=" + zone},
+			masked,
+		},
+		{"another zone", environment{dnsblZones: zone, tagDeny: zenTag}, zenTag},
+		{
+			"abuseipdb with a key",
+			environment{abuseIPDBKey: "k", tagLimitPercent: "abuseipdb:50"}, "",
+		},
+		{"crowdsec, though a list has its name", environment{
+			tagLists: "crowdsec=https://example.com/c.txt", tagDeny: "crowdsec",
+		}, `"crowdsec" cannot be used`},
+		{exploitTag, environment{tagDeny: exploitTag}, ""},
+		{
+			exploitTag + " with rule files off",
+			environment{tagDeny: exploitTag, rulesEnabled: disabled}, "",
+		},
+		{
+			exploitTag + " with the Core Rule Set off",
+			environment{tagDeny: exploitTag, wafMode: off}, "",
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := config.FromEnvironment(tc.env.lookupEnv)
+
+			switch {
+			case tc.want == "" && err != nil:
+				t.Errorf("error %v, want none", err)
+			case tc.want != "" && (err == nil || !strings.Contains(err.Error(), tc.want)):
+				t.Errorf("error %v, want one holding %s", err, tc.want)
+			case err != nil && strings.Contains(err.Error(), key):
+				t.Errorf("error %v shows the zone's key", err)
+			}
+		})
+	}
+}
+
+func TestErrorOfATagSettingLeavesOutAZoneKey(t *testing.T) {
+	t.Parallel()
+
+	const (
+		tag       = "dnsbl=" + spamhaus
+		emptyItem = "has an empty item in its list"
+		twice     = `"` + spamhausMasked + `" is listed twice`
+	)
+
+	for _, tc := range []struct{ name, value, want string }{
+		{tagDeny, tag + "," + tag, twice},
+		{tagDeny, tag + ",,", emptyItem},
+		{
+			tagLimitPercent, tag,
+			`"` + spamhausMasked + `" is not a tag, : and a percentage, ` +
+				"such as vpn:50 or asn=14061:25",
+		},
+		{tagLimitPercent, tag + ":50," + tag + " :25", twice},
+		{tagLimitPercent, tag + ":50,,", emptyItem},
+	} {
+		_, err := config.FromEnvironment(environment{tc.name: tc.value}.lookupEnv)
+
+		want := tc.name + ": " + tc.want
+		if err == nil || err.Error() != want {
+			t.Errorf("%s=%s gave the error %v, want %s", tc.name, tc.value, err, want)
+		}
+	}
+}
+
+func TestTagListURLFetchedAsAnotherListStopsTheStart(t *testing.T) {
+	t.Parallel()
+
+	const lapi = "http://172.17.0.1:8080"
+
+	for _, tc := range []struct {
+		name, listURL string
+		env           environment
+	}{
+		{"a blocklist", dropURL, environment{blocklistURLs: dropURL}},
+		{"the file of AS:percent lines", asnURL, environment{asnLimitPercentURL: asnURL}},
+		{
+			"the CrowdSec decision list", lapi + "/v1/decisions",
+			environment{"SWW_CROWDSEC_LAPI_URL": lapi, "SWW_CROWDSEC_LAPI_KEY": "key"},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			tc.env[tagLists] = "dup=" + tc.listURL
+
+			want := tagLists + `: "` + tc.listURL + `" is in SWW_BLOCKLIST_URLS, is ` +
+				"SWW_ASN_LIMIT_PERCENT_URL or is the CrowdSec decision list too"
+
+			_, err := config.FromEnvironment(tc.env.lookupEnv)
+			if err == nil || err.Error() != want {
+				t.Errorf("error %v, want %s", err, want)
+			}
+		})
+	}
+}
+
 func TestBiasedThresholdsAsSet(t *testing.T) {
 	t.Parallel()
 
 	cfg := fromEnvironment(t, environment{})
-	if len(cfg.ASNLimitPercent) != 0 || len(cfg.CountryLimitPercent) != 0 ||
-		len(cfg.ASNBytesPercent) != 0 || len(cfg.CountryBytesPercent) != 0 ||
+	if len(cfg.ASNBytesPercent) != 0 || len(cfg.CountryBytesPercent) != 0 ||
 		cfg.UnknownLimitPercent != 100 {
-		t.Errorf("biased thresholds %v, %v, %v, %v and %d by default, "+
-			"want four empty lists and 100", cfg.ASNLimitPercent, cfg.CountryLimitPercent,
+		t.Errorf("biased thresholds %v, %v and %d by default, "+
+			"want two empty lists and 100",
 			cfg.ASNBytesPercent, cfg.CountryBytesPercent, cfg.UnknownLimitPercent)
 	}
 
 	// AS numbers and countries in either case, an AS number with leading
 	// zeros, 0 and 100.
 	cfg = fromEnvironment(t, environment{
-		asnLimitPercent:     "AS14061:50, as16276:0,AS045102:100",
-		countryLimitPercent: "cn:25,RU:50",
 		asnBytesPercent:     "as16276:75",
 		countryBytesPercent: "ru:10",
 		unknownLimitPercent: "0",
 	})
 
 	for name, tc := range map[string]struct{ got, want map[string]int64 }{
-		asnLimitPercent: {
-			cfg.ASNLimitPercent,
-			map[string]int64{"AS14061": 50, "AS16276": 0, "AS45102": 100},
-		},
-		countryLimitPercent: {cfg.CountryLimitPercent, map[string]int64{"CN": 25, "RU": 50}},
 		asnBytesPercent:     {cfg.ASNBytesPercent, map[string]int64{"AS16276": 75}},
 		countryBytesPercent: {cfg.CountryBytesPercent, map[string]int64{"RU": 10}},
 	} {
@@ -1406,16 +1567,16 @@ func TestInvalidBiasedThresholdStopsTheStartSayingWhatIsWrong(t *testing.T) {
 	)
 
 	for _, tc := range []struct{ name, value, want string }{
-		{asnLimitPercent, "14061:50", `"14061"` + notASN},
-		{asnLimitPercent, "AS4294967296:50", `"AS4294967296"` + notASN},
-		{asnLimitPercent, "AS14061", `"AS14061"` + notItem},
-		{asnLimitPercent, "AS14061:101", `"101"` + notPercent},
-		{asnLimitPercent, "AS14061:50,as14061:25", `"as14061" is listed twice`},
+		{asnBytesPercent, "14061:50", `"14061"` + notASN},
+		{asnBytesPercent, "AS4294967296:50", `"AS4294967296"` + notASN},
+		{asnBytesPercent, "AS14061", `"AS14061"` + notItem},
+		{asnBytesPercent, "AS14061:101", `"101"` + notPercent},
+		{asnBytesPercent, "AS14061:50,as14061:25", `"as14061" is listed twice`},
 		{
-			countryLimitPercent, "nk:25",
+			countryBytesPercent, "nk:25",
 			`"nk" is not a two-letter country code such as de or kp`,
 		},
-		{countryLimitPercent, "cn:25,CN:50", `"CN" is listed twice`},
+		{countryBytesPercent, "cn:25,CN:50", `"CN" is listed twice`},
 		{asnBytesPercent, "AS14061:-1", `"-1"` + notPercent},
 		{countryBytesPercent, "cn:50%", `"50%"` + notPercent},
 		{unknownLimitPercent, "101", `"101"` + notPercent},
@@ -2003,23 +2164,37 @@ func TestInvalidValueStopsTheStart(t *testing.T) {
 		{lookupSource, "ipinfo"}, {lookupSource, "GeoJS"}, {lookupSource, ""},
 		{lookupTimeout, off}, {lookupTimeout, "0s"}, {lookupTimeout, "1"},
 		{addLookupHeaders, "yes"},
-		{deniedCountries, "nk"},
-		{deniedCountries, "kp,,ir"},
-		{deniedCountries, "prk"},
-		{deniedCountries, "408"},
-		{deniedCountries, "k"},
-		{deniedCountries, "eu"},
-		{deniedCountries, "un"},
-		{deniedCountries, "su"},
+		{allowedCountries, "nk"},
+		{allowedCountries, "kp,,ir"},
+		{allowedCountries, "prk"},
+		{allowedCountries, "408"},
+		{allowedCountries, "k"},
+		{allowedCountries, "eu"},
+		{allowedCountries, "un"},
+		{allowedCountries, "su"},
 		{allowedCountries, "ac"},
 		{allowedCountries, "uk"},
 		{allowedCountries, "zz"},
 		{allowedCountries, "de,germany"},
-		{asnLimitPercent, "AS14061:50,,AS16276:50"}, {asnLimitPercent, "ASX:50"},
-		{asnLimitPercent, "AS14061:"}, {asnLimitPercent, "AS14061 :50"},
-		{asnLimitPercent, "AS14061:1.5"}, {asnLimitPercent, "AS-1:50"},
-		{countryLimitPercent, "cn"}, {countryLimitPercent, "cn:"},
-		{countryLimitPercent, "cn:25:50"}, {countryLimitPercent, "china:25"},
+		{asnBytesPercent, "AS14061:50,,AS16276:50"}, {asnBytesPercent, "ASX:50"},
+		{asnBytesPercent, "AS14061:"}, {asnBytesPercent, "AS14061 :50"},
+		{asnBytesPercent, "AS14061:1.5"}, {asnBytesPercent, "AS-1:50"},
+		{countryBytesPercent, "cn"}, {countryBytesPercent, "cn:"},
+		{countryBytesPercent, "cn:25:50"}, {countryBytesPercent, "china:25"},
+		{tagDeny, "a,,b"}, {tagDeny, "country=nk"}, {tagDeny, "asn=abc"},
+		{tagDeny, "asn="}, {tagDeny, "torexit,TOREXIT"}, {tagDeny, "torexti"},
+		{tagDeny, zenTag}, {tagDeny, "abuseipdb"}, {tagDeny, "crowdsec"},
+		{tagLimitPercent, "torexti:50"}, {tagLimitPercent, "dnsbl=zen.example:50"},
+		{tagLimitPercent, "abuseipdb:50"}, {tagLimitPercent, "crowdsec:50"},
+		{tagLimitPercent, "vpn :50"}, {tagLimitPercent, "vpn"}, {tagLimitPercent, ":50"},
+		{tagLimitPercent, "vpn:"}, {tagLimitPercent, "vpn:0"}, {tagLimitPercent, "vpn:100"},
+		{tagLimitPercent, "vpn:1.5"}, {tagLimitPercent, "vpn:50,VPN:25"},
+		{tagLimitPercent, "exploitsignature:50"}, {tagLimitPercent, "asn=abc:50"},
+		{tagLists, torExitTag}, {tagLists, "=https://example.com/a.txt"},
+		{tagLists, "a,b=https://example.com/a.txt"},
+		{tagLists, "a=ftp://example.com/a.txt"},
+		{tagLists, "a=https://example.com/a.txt,A=https://example.com/b.txt"},
+		{tagLists, "a=https://example.com/a.txt,b=https://example.com/a.txt"},
 		{asnBytesPercent, "AS14061:101"}, {countryBytesPercent, "su:50"},
 		{unknownLimitPercent, ""}, {unknownLimitPercent, "-1"},
 		{unknownLimitPercent, "50%"},
@@ -2031,6 +2206,25 @@ func TestInvalidValueStopsTheStart(t *testing.T) {
 		{logLevel, "INFO"}, {logLevel, "warning"}, {logLevel, "trace"}, {logLevel, ""},
 		{rulesEnabled, "yes"}, {rulesEnabled, "True"},
 	})
+
+	wantExploitTagStopsTheStartWithRulesAndCoreRuleSetOff(t)
+}
+
+// wantExploitTagStopsTheStartWithRulesAndCoreRuleSetOff checks that with rule
+// files off, and either setting turning off the Core Rule Set, the tag
+// exploitsignature in SWW_TAG_DENY stops the start.
+func wantExploitTagStopsTheStartWithRulesAndCoreRuleSetOff(t *testing.T) {
+	t.Helper()
+
+	for _, name := range []string{wafMode, wafAnomalyThreshold} {
+		_, err := config.FromEnvironment(environment{
+			tagDeny: exploitTag, rulesEnabled: disabled, name: off,
+		}.lookupEnv)
+		if err == nil || !strings.HasPrefix(err.Error(), tagDeny+": ") {
+			t.Errorf("%s=off with rule files off gave the error %v, want one naming %s",
+				name, err, tagDeny)
+		}
+	}
 }
 
 func TestInvalidBanOrStateValueStopsTheStart(t *testing.T) {
@@ -2285,11 +2479,11 @@ func TestLogsEachSettingWithItsValue(t *testing.T) {
 		lookupSource:         defaultLookupSource,
 		lookupDBPath:         "",
 		lookupTimeout:        "800ms",
-		addLookupHeaders:     "false",
-		deniedCountries:      "",
+		addLookupHeaders:     disabled,
 		allowedCountries:     "",
-		asnLimitPercent:      "",
-		countryLimitPercent:  "",
+		tagLists:             "",
+		tagDeny:              "",
+		tagLimitPercent:      "",
 		asnBytesPercent:      "",
 		countryBytesPercent:  "",
 		unknownLimitPercent:  "100",

internal/discriminator/abuseipdb.go

@@ -8,18 +8,20 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 )
 
-// abuseIPDB notes AbuseIPDB, as noteHit does, with the score, when its score
-// of the client is a hit, and refuses the request when SWW_REPUTATION_ACTION
-// is deny, as dnsbl does for a zone. While SWW_ABUSEIPDB_KEY is unset it does
-// nothing. A client without a score is checked in the background, by the
-// request's address, if its history counts an offence, and the request does
-// not wait for the answer. The score is then used for each address of the
-// client. Its figures are the score and SWW_ABUSEIPDB_MIN_SCORE.
+// abuseIPDB adds the tag abuseipdb and notes AbuseIPDB, as noteHit does, with
+// the score, when its score of the client is a hit, and refuses the request
+// when SWW_REPUTATION_ACTION is deny, as dnsbl does for a zone. While
+// SWW_ABUSEIPDB_KEY is unset it does nothing. A client without a score is
+// checked in the background, by the request's address, if its history counts
+// an offence, and the request does not wait for the answer. The score is then
+// used for each address of the client. Its figures are the score and
+// SWW_ABUSEIPDB_MIN_SCORE.
 type abuseIPDB struct{}
 
 func (abuseIPDB) name() string { return "abuseipdb" }
@@ -39,6 +41,7 @@ func (abuseIPDB) check(ctx context.Context, rq *request, _ time.Time) *verdict {
 	}
 
 	rq.abuseIPDBHit = true
+	rq.addTag(config.AbuseIPDBTag)
 	rq.noteHit(bans.ReputationHit{Source: reputation.AbuseIPDBSource, Score: &score},
 		"scored by AbuseIPDB at or over SWW_ABUSEIPDB_MIN_SCORE")
 

internal/discriminator/answertime_test.go

@@ -335,7 +335,7 @@ func newDiscriminatorInBubble(
 ) (*discriminator.Server, *output) {
 	t.Helper()
 
-	settings := map[string]string{deniedCountries: "KP"}
+	settings := map[string]string{tagDeny: "country=KP"}
 	maps.Copy(settings, env)
 
 	server, out, _ := newDiscriminator(t, unansweredGeoJSURL, time.Now, settings)
@@ -542,7 +542,7 @@ func TestDiscriminatorAnswersWithinTheTimeLimitWhileEveryOutsideSourceHangs(
 
 		return discriminator.New(params)
 	}, held, time.Now, map[string]string{
-		deniedCountries: "KP", wafMode: block,
+		tagDeny: "country=KP", wafMode: block,
 		dnsblZones: dnsblZone, dnsblResolver: resolver.LocalAddr().String(),
 		abuseIPDBKey:  accountKey,
 		blocklistURLs: held + "/drop.txt", asnLimitPercentURL: held + "/asn.txt",

internal/discriminator/bans_test.go

@@ -211,7 +211,7 @@ func TestBannedClientIsRefusedBeforeItsCountryIsLookedUp(t *testing.T) {
 		lookupTimeout:      "1h",
 		rateLimitPerMinute: "1",
 		banScopeV4Prefix:   "24",
-		deniedCountries:    "kp",
+		tagDeny:            denyKP,
 	})
 
 	// fromDE's ban covers otherClient, which is refused unasked about.
@@ -266,7 +266,7 @@ func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
 				lookupTimeout:      "1h",
 				rateLimitPerMinute: "1",
 				denyNets:           denied,
-				deniedCountries:    "kp",
+				tagDeny:            denyKP,
 			}
 
 			if tc.setting != "" {
@@ -276,7 +276,7 @@ func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
 			s, _, _ := startWithClock(t, geojsURL, env)
 
 			s.get(denied, tc.status, requestlog.ActionDenied)
-			s.get(fromKP, tc.status, requestlog.ActionCountryDenied)
+			s.get(fromKP, tc.status, requestlog.ActionDenied)
 			s.get(fromDE, http.StatusOK, requestlog.ActionForward)
 			s.get(fromDE, tc.status, requestlog.ActionRateLimited)
 			s.get(fromDE, tc.status, requestlog.ActionBanned)
@@ -291,7 +291,7 @@ func TestBanNotes(t *testing.T) {
 	s, clk, server := startWithClock(t, geojsURL, map[string]string{
 		lookupTimeout:      "1h",
 		rateLimitPerMinute: "1",
-		deniedCountries:    "kp",
+		tagDeny:            denyKP,
 	})
 	start := clk.Now()
 

internal/discriminator/biased.go

@@ -17,30 +17,31 @@ type percentage struct {
 }
 
 // biasedThresholdsSet reports whether a biased threshold can lower a
-// client's limits: one of its lists is not empty,
-// SWW_UNKNOWN_LIMIT_PERCENT is below 100, or SWW_ASN_LIMIT_PERCENT_URL
-// is set. The client's lookup is then needed before its request goes on.
+// client's limits by its lookup: SWW_ASN_BYTES_PERCENT or
+// SWW_COUNTRY_BYTES_PERCENT is not empty, SWW_UNKNOWN_LIMIT_PERCENT is
+// below 100, or SWW_ASN_LIMIT_PERCENT_URL is set. The client's lookup is
+// then needed before its request goes on.
 func biasedThresholdsSet(cfg *config.Config) bool {
-	return len(cfg.ASNLimitPercent) > 0 || len(cfg.CountryLimitPercent) > 0 ||
-		len(cfg.ASNBytesPercent) > 0 || len(cfg.CountryBytesPercent) > 0 ||
+	return len(cfg.ASNBytesPercent) > 0 || len(cfg.CountryBytesPercent) > 0 ||
 		cfg.UnknownLimitPercent < whole || cfg.ASNLimitPercentURL != ""
 }
 
 // limitPercentages returns the client's limit percentages, for the rate
-// limits and for the byte limits, by its AS number and country as looked
-// up, each "" when unknown, and the blocklists, DNSBL zones and AbuseIPDB
-// that list it. Each is the lowest of those the settings give it, the
-// first of them in the order below when several are lowest: the
-// percentage SWW_ASN_LIMIT_PERCENT gives its AS number, the one the file
-// SWW_ASN_LIMIT_PERCENT_URL names gives it, the one
-// SWW_COUNTRY_LIMIT_PERCENT gives its country, for a client without a
-// country, unless its request skipped the wait for GeoJS,
-// SWW_UNKNOWN_LIMIT_PERCENT, for a client a blocklist lists, the
-// percentage of SWW_BLOCKLIST_ACTION while it is limit, and for a client
-// a DNSBL zone's verdict lists, or whose AbuseIPDB score is a hit, the
-// percentage of SWW_REPUTATION_ACTION while it is limit. For the byte
-// limits, SWW_ASN_BYTES_PERCENT and SWW_COUNTRY_BYTES_PERCENT take the
-// place of the first three for an AS number or a country they list.
+// limits and for the byte limits, by its tags, its AS number and country
+// as looked up, each "" when unknown, and the blocklists, DNSBL zones and
+// AbuseIPDB that list it. Each is the lowest of those the settings give
+// it, the first of them in the order below when several are lowest: the
+// percentage SWW_TAG_LIMIT_PERCENT gives its asn= tag, the one the file
+// SWW_ASN_LIMIT_PERCENT_URL names gives its AS number, the one
+// SWW_TAG_LIMIT_PERCENT gives its country= tag, the lowest it gives its
+// other tags, for a client without a country, unless its request skipped
+// the wait for GeoJS, SWW_UNKNOWN_LIMIT_PERCENT, for a client a blocklist
+// lists, the percentage of SWW_BLOCKLIST_ACTION while it is limit, and
+// for a client a DNSBL zone's verdict lists, or whose AbuseIPDB score is
+// a hit, the percentage of SWW_REPUTATION_ACTION while it is limit. For
+// the byte limits, SWW_ASN_BYTES_PERCENT and SWW_COUNTRY_BYTES_PERCENT
+// take the place of the first three for an AS number or a country they
+// list.
 func (rq *request) limitPercentages() (percentage, percentage) {
 	cfg := rq.h.config
 	asn, country := rq.line.ASN, rq.line.Country
@@ -65,10 +66,18 @@ func (rq *request) limitPercentages() (percentage, percentage) {
 		reputationListed = percentage{cfg.ReputationLimitPercent, "SWW_REPUTATION_ACTION"}
 	}
 
-	asnRequests := lowest(given(cfg.ASNLimitPercent, asn, "SWW_ASN_LIMIT_PERCENT"),
-		fetched)
-	countryRequests := given(cfg.CountryLimitPercent, country,
-		"SWW_COUNTRY_LIMIT_PERCENT")
+	const tagSetting = "SWW_TAG_LIMIT_PERCENT"
+
+	asnRequests := lowest(given(cfg.TagLimitPercent, asnTag(asn), tagSetting), fetched)
+	countryRequests := given(cfg.TagLimitPercent, countryTag(country), tagSetting)
+
+	otherTags := percentage{percent: whole}
+
+	for _, tag := range rq.line.Tags {
+		if tag != asnTag(asn) && tag != countryTag(country) {
+			otherTags = lowest(otherTags, given(cfg.TagLimitPercent, tag, tagSetting))
+		}
+	}
 
 	asnBytes, countryBytes := asnRequests, countryRequests
 	if _, listed := cfg.ASNBytesPercent[asn]; listed {
@@ -79,12 +88,13 @@ func (rq *request) limitPercentages() (percentage, percentage) {
 		countryBytes = given(cfg.CountryBytesPercent, country, "SWW_COUNTRY_BYTES_PERCENT")
 	}
 
-	return lowest(asnRequests, countryRequests, unknown, blocklisted, reputationListed),
-		lowest(asnBytes, countryBytes, unknown, blocklisted, reputationListed)
+	return lowest(asnRequests, countryRequests, otherTags, unknown, blocklisted,
+			reputationListed),
+		lowest(asnBytes, countryBytes, otherTags, unknown, blocklisted, reputationListed)
 }
 
 // given returns the percentage percents, the setting named setting, gives
-// code, an AS number or a country, or whole when it does not list code.
+// code, an AS number, a country or a tag, or whole when it does not list code.
 func given(percents map[string]int64, code, setting string) percentage {
 	percent, listed := percents[code]
 	if !listed {

internal/discriminator/biased_test.go

@@ -22,8 +22,7 @@ import (
 
 // The biased thresholds.
 const (
-	asnLimitPercent     = "SWW_ASN_LIMIT_PERCENT"
-	countryLimitPercent = "SWW_COUNTRY_LIMIT_PERCENT"
+	tagLimitPercent     = "SWW_TAG_LIMIT_PERCENT"
 	asnBytesPercent     = "SWW_ASN_BYTES_PERCENT"
 	countryBytesPercent = "SWW_COUNTRY_BYTES_PERCENT"
 	unknownLimitPercent = "SWW_UNKNOWN_LIMIT_PERCENT"
@@ -35,6 +34,11 @@ const (
 	asnDEHalf     = asnDE + ":50"
 	asnDEQuarter  = asnDE + ":25"
 	countryDEHalf = "de:50"
+	// The same, as SWW_TAG_LIMIT_PERCENT names fromDE's tags.
+	asnTagDEHalf        = "asn=64496:50"
+	asnTagDEQuarter     = "asn=64496:25"
+	countryTagDEHalf    = "country=DE:50"
+	countryTagDEQuarter = "country=DE:25"
 	// noCountry is in an AS of its own, AS64500, and in no country.
 	noCountry = "192.0.2.80"
 	// fourAMinute is the rate limit these tests set: half of it is 2
@@ -54,8 +58,8 @@ func TestEachBiasedThresholdLowersTheRateLimits(t *testing.T) {
 	for _, tc := range []struct {
 		setting, value, from string
 	}{
-		{asnLimitPercent, asnDEHalf, fromDE},
-		{countryLimitPercent, countryDEHalf, fromDE},
+		{tagLimitPercent, asnTagDEHalf, fromDE},
+		{tagLimitPercent, countryTagDEHalf, fromDE},
 		{unknownLimitPercent, "50", unplaced},
 	} {
 		t.Run(tc.setting, func(t *testing.T) {
@@ -96,8 +100,8 @@ func TestEachBiasedThresholdLowersTheByteLimits(t *testing.T) {
 	for _, tc := range []struct {
 		setting, value, from string
 	}{
-		{asnLimitPercent, asnDEHalf, fromDE},
-		{countryLimitPercent, "DE:50", fromDE},
+		{tagLimitPercent, asnTagDEHalf, fromDE},
+		{tagLimitPercent, "Country=de:50", fromDE},
 		{unknownLimitPercent, "50", unplaced},
 		{asnBytesPercent, "as64496:50", fromDE},
 		{countryBytesPercent, countryDEHalf, fromDE},
@@ -151,13 +155,13 @@ func TestBytesPercentSettingsTakeThePlaceOfTheOthersForByteLimits(t *testing.T)
 		},
 		{
 			"raising the byte limits back",
-			map[string]string{asnLimitPercent: asnDEHalf, asnBytesPercent: asnDE + ":100"},
-			"50 from " + asnLimitPercent, none, "",
+			map[string]string{tagLimitPercent: asnTagDEHalf, asnBytesPercent: asnDE + ":100"},
+			"50 from " + tagLimitPercent, none, "",
 		},
 		{
 			"raising the byte limits back, by country",
-			map[string]string{countryLimitPercent: countryDEHalf, countryBytesPercent: "de:100"},
-			"50 from " + countryLimitPercent, none, "",
+			map[string]string{tagLimitPercent: countryTagDEHalf, countryBytesPercent: "de:100"},
+			"50 from " + tagLimitPercent, none, "",
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
@@ -184,19 +188,19 @@ func TestBytesPercentSettingsTakeThePlaceOfTheOthersForByteLimits(t *testing.T)
 func TestZeroPercentIsAZeroAllowance(t *testing.T) {
 	t.Parallel()
 
-	s, _, _ := startWithLookups(t, map[string]string{asnLimitPercent: asnDE + ":0"})
+	s, _, _ := startWithLookups(t, map[string]string{unknownLimitPercent: "0"})
 
 	// The first request breaks the limit, and bans the client; the log line
 	// gives the 0.
-	line := s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
+	line := s.get(unplaced, http.StatusForbidden, requestlog.ActionRateLimited)
 	if line.fields["limit_percent"] != float64(0) ||
-		line.fields["limit_percent_setting"] != asnLimitPercent {
+		line.fields["limit_percent_setting"] != unknownLimitPercent {
 		t.Errorf("log line has limit_percent %v from %v, want 0 from %s",
 			line.fields["limit_percent"], line.fields["limit_percent_setting"],
-			asnLimitPercent)
+			unknownLimitPercent)
 	}
 
-	s.get(fromDE, http.StatusForbidden, requestlog.ActionBanned)
+	s.get(unplaced, http.StatusForbidden, requestlog.ActionBanned)
 }
 
 func TestLowestPercentageApplies(t *testing.T) {
@@ -211,29 +215,29 @@ func TestLowestPercentageApplies(t *testing.T) {
 	}{
 		{
 			"the country's",
-			map[string]string{asnLimitPercent: asnDEHalf, countryLimitPercent: "de:25"},
-			fromDE, "25 from " + countryLimitPercent,
+			map[string]string{tagLimitPercent: asnTagDEHalf + "," + countryTagDEQuarter},
+			fromDE, "25 from " + tagLimitPercent,
 		},
 		{
 			"the AS number's",
-			map[string]string{asnLimitPercent: asnDEQuarter, countryLimitPercent: countryDEHalf},
-			fromDE, "25 from " + asnLimitPercent,
+			map[string]string{tagLimitPercent: asnTagDEQuarter + "," + countryTagDEHalf},
+			fromDE, "25 from " + tagLimitPercent,
 		},
 		{
 			"the AS number's, the first of two alike",
-			map[string]string{asnLimitPercent: asnDEQuarter, countryLimitPercent: "de:25"},
-			fromDE, "25 from " + asnLimitPercent,
+			map[string]string{tagLimitPercent: asnTagDEQuarter + "," + countryTagDEQuarter},
+			fromDE, "25 from " + tagLimitPercent,
 		},
 		{
 			"that for a client without a country",
-			map[string]string{asnLimitPercent: "AS64500:50", unknownLimitPercent: "25"},
+			map[string]string{tagLimitPercent: "asn=64500:50", unknownLimitPercent: "25"},
 			noCountry, "25 from " + unknownLimitPercent,
 		},
 		{
 			// SWW_UNKNOWN_LIMIT_PERCENT is left at its default, 100.
 			"the AS number's, for a client without a country",
-			map[string]string{asnLimitPercent: "AS64500:25"},
-			noCountry, "25 from " + asnLimitPercent,
+			map[string]string{tagLimitPercent: "asn=64500:25"},
+			noCountry, "25 from " + tagLimitPercent,
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
@@ -304,8 +308,12 @@ func TestRequestWaitsForItsLookupWhileABiasedThresholdIsSet(t *testing.T) {
 		setting, value string
 		waits          bool
 	}{
-		{asnLimitPercent, asnDEHalf, true},
-		{countryLimitPercent, countryDEHalf, true},
+		{tagLimitPercent, asnTagDEHalf, true},
+		{tagLimitPercent, countryTagDEHalf, true},
+		{tagDeny, denyKP, true},
+		// A tag the lookup does not give needs no answer.
+		{tagLimitPercent, "vpn:50", false},
+		{tagDeny, "vpn", false},
 		{asnBytesPercent, asnDEHalf, true},
 		{countryBytesPercent, countryDEHalf, true},
 		{unknownLimitPercent, "99", true},
@@ -320,7 +328,9 @@ func TestRequestWaitsForItsLookupWhileABiasedThresholdIsSet(t *testing.T) {
 			// says, with a GeoJS that never answers.
 			synctest.Test(t, func(t *testing.T) {
 				server, out, _ := newDiscriminator(t, unansweredGeoJSURL, time.Now,
-					map[string]string{lookupTimeout: timeout.String(), tc.setting: tc.value})
+					map[string]string{
+						lookupTimeout: timeout.String(), tagLists: "vpn=" + vpnList, tc.setting: tc.value,
+					})
 				began := time.Now()
 
 				serveFromDE(t, server, http.MethodPost, strings.NewReader("ab"))
@@ -363,15 +373,15 @@ func TestBanForALoweredLimitGivesThePercentageInItsNotesAndItsAlert(t *testing.T
 		{
 			// A quarter of 12 requests a minute is 3: the fourth breaks it.
 			"a rate limit",
-			map[string]string{rateLimitPerMinute: "12", asnLimitPercent: asnDEQuarter},
+			map[string]string{rateLimitPerMinute: "12", tagLimitPercent: asnTagDEQuarter},
 			3, http.StatusForbidden, requestlog.ActionRateLimited,
-			"requests per minute over the limit of 3", "25 from " + asnLimitPercent,
+			"requests per minute over the limit of 3", "25 from " + tagLimitPercent,
 		},
 		{
 			// The byte limits' percentage, not the rate limits'.
 			"a byte limit",
 			map[string]string{
-				bytesLimitPerMinute: twoUploads, asnLimitPercent: asnDEQuarter,
+				bytesLimitPerMinute: twoUploads, tagLimitPercent: asnTagDEQuarter,
 				asnBytesPercent: asnDEHalf,
 			},
 			0, http.StatusOK, requestlog.ActionForward,
@@ -487,7 +497,7 @@ func wantPercent(t *testing.T, what string, percent *int64, setting, want string
 }
 
 // percentText gives a limit percentage and the setting that gave it as
-// text, such as "50 from SWW_ASN_LIMIT_PERCENT", or none when both are
+// text, such as "50 from SWW_TAG_LIMIT_PERCENT", or none when both are
 // left out.
 func percentText(percent *int64, setting string) string {
 	switch {

internal/discriminator/coreruleset.go

@@ -17,9 +17,10 @@ import (
 // SWW_WAF_MODE is off or SWW_WAF_EXEMPT_PATHS exempts its path, as
 // pathExempt decides, and notes the rules it matched and its score in the
 // log line, and the rules in the metrics. A score at or over
-// SWW_WAF_ANOMALY_THRESHOLD is a match: it raises the waf_block alert,
-// and in block mode refuses the request with 403, which is an offence its
-// client's history counts. Its figures are the score and the threshold.
+// SWW_WAF_ANOMALY_THRESHOLD is a match: it adds the tag exploitsignature,
+// raises the waf_block alert, and in block mode refuses the request with 403,
+// which is an offence its client's history counts. Its figures are the score
+// and the threshold.
 type coreRuleSet struct{}
 
 func (coreRuleSet) name() string { return "core_rule_set" }
@@ -50,6 +51,7 @@ func (coreRuleSet) check(_ context.Context, rq *request, _ time.Time) *verdict {
 		return nil
 	}
 
+	rq.addTag(config.ExploitSignatureTag)
 	rq.alertWAFBlock(result)
 
 	if cfg.WAFMode == config.WAFModeDetect {

internal/discriminator/coreruleset_test.go

@@ -61,6 +61,41 @@ func wantWAF(t *testing.T, line logLine, score *int, ruleIDs ...int) {
 	}
 }
 
+func TestCoreRuleSetMatchAddsTheExploitSignatureTag(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range []struct {
+		name   string
+		mode   string
+		status int
+		action string
+	}{
+		{block, block, http.StatusForbidden, requestlog.ActionWAFBlocked},
+		{detect, detect, http.StatusOK, requestlog.ActionForward},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			s, _, _ := startWithClock(t, "", map[string]string{wafMode: tc.mode})
+
+			wantTags(t, s.request(client, sqlInjection, tc.status, tc.action),
+				"exploitsignature")
+			wantTags(t, s.get(client, http.StatusOK, requestlog.ActionForward))
+		})
+	}
+}
+
+func TestDetectedAttackIsRefusedByTagDenyLast(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{
+		wafMode: detect, tagDeny: "exploitsignature",
+	})
+
+	line := s.request(client, sqlInjection, http.StatusForbidden, requestlog.ActionDenied)
+	wantHeuristic(t, line, "tag_deny", `{"tag": "exploitsignature"}`)
+}
+
 func TestCoreRuleSetRefusesAttacksInBlockModeAndOnlyLogsThemInDetectMode(t *testing.T) {
 	t.Parallel()
 

internal/discriminator/countries.go

@@ -1,7 +1,6 @@
 package discriminator
 
-// The heuristic countries. It reads SWW_DENIED_COUNTRIES and
-// SWW_EXCLUSIVELY_ALLOWED_COUNTRIES.
+// The heuristic countries. It reads SWW_EXCLUSIVELY_ALLOWED_COUNTRIES.
 
 import (
 	"context"
@@ -11,32 +10,26 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 )
 
-// countries refuses a request by the client's country as it was looked up. A
-// client without a country, or whose country cannot be found, is refused only
-// by SWW_EXCLUSIVELY_ALLOWED_COUNTRIES. Its figures are the country and the
-// setting that refused it.
+// countries refuses a request when SWW_EXCLUSIVELY_ALLOWED_COUNTRIES is set and
+// does not hold the client's country as it was looked up. A client without a
+// country, or whose country cannot be found, is refused. Its figures are the
+// country and the setting that refused it.
 type countries struct{}
 
 func (countries) name() string { return "countries" }
 
 func (countries) check(_ context.Context, rq *request, _ time.Time) *verdict {
-	denied := rq.h.config.DeniedCountries
 	allowed := rq.h.config.ExclusivelyAllowedCountries
 	country := rq.line.Country
 
-	var setting string
-
-	switch {
-	case slices.Contains(denied, country):
-		setting = "SWW_DENIED_COUNTRIES"
-	case len(allowed) > 0 && !slices.Contains(allowed, country):
-		setting = "SWW_EXCLUSIVELY_ALLOWED_COUNTRIES"
-	default:
+	if len(allowed) == 0 || slices.Contains(allowed, country) {
 		return nil
 	}
 
 	return &verdict{
 		action: requestlog.ActionCountryDenied,
-		figures: map[string]any{"country": country, "setting": setting},
+		figures: map[string]any{
+			"country": country, "setting": "SWW_EXCLUSIVELY_ALLOWED_COUNTRIES",
+		},
 	}
 }

internal/discriminator/countries_test.go

@@ -33,13 +33,13 @@ func TestCountryLists(t *testing.T) {
 		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"},
+			"with a country in SWW_TAG_DENY",
+			map[string]string{tagDeny: denyKP, allowedCountries: "de,fr"},
 			[]string{fromKP, unplaced},
 		},
 	} {
@@ -95,12 +95,12 @@ func TestCountryRefusalNamesItsHeuristicCountryAndSetting(t *testing.T) {
 
 	geojsURL, _ := startGeoJS(t)
 	s, _, _ := startWithClock(t, geojsURL, map[string]string{
-		lookupTimeout: "1h", deniedCountries: "kp", allowedCountries: "de",
+		lookupTimeout: "1h", allowedCountries: "de",
 	})
 
 	line := s.get(fromKP, http.StatusForbidden, requestlog.ActionCountryDenied)
 	wantHeuristic(t, line, "countries",
-		`{"country": "KP", "setting": "SWW_DENIED_COUNTRIES"}`)
+		`{"country": "KP", "setting": "SWW_EXCLUSIVELY_ALLOWED_COUNTRIES"}`)
 
 	line = s.get(unplaced, http.StatusForbidden, requestlog.ActionCountryDenied)
 	wantHeuristic(t, line, "countries",
@@ -119,7 +119,7 @@ func TestCountryRefusalKeepsARequestFromTheApp(t *testing.T) {
 	addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
 		trustedProxies:   trustLocalhost,
 		lookupTimeout:    "1h",
-		deniedCountries: "kp",
+		allowedCountries: "de",
 	})
 
 	req := newRequest(t, http.MethodPost, addr, "/", strings.NewReader("a body"))
@@ -202,7 +202,7 @@ func TestPrivateAddressIsNeverLookedUp(t *testing.T) {
 		env  map[string]string
 	}{
 		{"no setting needs the lookup", nil},
-		{"a country list is set", map[string]string{deniedCountries: "kp"}},
+		{"a tag setting needs it", map[string]string{tagDeny: denyKP}},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()

internal/discriminator/crowdsec.go

@@ -8,14 +8,15 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 )
 
 // crowdSec refuses a request when a decision of the CrowdSec decision list on
-// the client is in force at now. It then notes the list, as noteHit does, and
-// bans the client until that decision ends. Its figures are the decision's
-// scenario and when it ends.
+// the client is in force at now. It then adds the tag crowdsec, notes the
+// list, as noteHit does, and bans the client until that decision ends. Its
+// figures are the decision's scenario and when it ends.
 type crowdSec struct{}
 
 func (crowdSec) name() string { return "crowdsec" }
@@ -26,6 +27,7 @@ func (crowdSec) check(_ context.Context, rq *request, now time.Time) *verdict {
 		return nil
 	}
 
+	rq.addTag(config.CrowdSecTag)
 	rq.noteHit(bans.ReputationHit{Source: rq.h.config.CrowdSecDecisionsURL},
 		"listed by the CrowdSec decision list")
 	rq.banForCrowdSec(now, decision)

internal/discriminator/crowdsec_test.go

@@ -108,6 +108,7 @@ func TestCrowdSecBanNamesItsHeuristicScenarioAndEnd(t *testing.T) {
 	line := s.get(client, http.StatusForbidden, requestlog.ActionBanned)
 	wantHeuristic(t, line, "crowdsec", `{"scenario": "crowdsecurity/ssh-bf", `+
 		`"expires": "`+requestlog.FormatTime(clk.Now().Add(4*time.Hour))+`"}`)
+	wantTags(t, line, "crowdsec")
 }
 
 func TestEndedCrowdSecDecisionNoLongerBansThoughTheCopyStillHoldsIt(t *testing.T) {

internal/discriminator/discriminator_test.go

@@ -414,7 +414,7 @@ func TestReportNeverReachesAQuestionStillBeingHandled(t *testing.T) {
 
 	geojsURL, asked, release := startHeldGeoJS(t)
 	s := startDiscriminator(t, geojsURL, map[string]string{
-		lookupTimeout: "1h", deniedCountries: "kp", bytesLimitPerMinute: byteLimit,
+		lookupTimeout: "1h", tagDeny: denyKP, bytesLimitPerMinute: byteLimit,
 	})
 
 	first := s.question(siteA, client, "/")
@@ -765,7 +765,7 @@ func TestAllowCarriesTheLookupHeadersWhileTheSettingIsSet(t *testing.T) {
 
 			geojsURL, _ := startGeoJS(t)
 			s := startDiscriminator(t, geojsURL, map[string]string{
-				addLookupHeaders: tc.setting, lookupTimeout: "1h", deniedCountries: "kp",
+				addLookupHeaders: tc.setting, lookupTimeout: "1h", tagDeny: denyKP,
 			})
 
 			got := s.ask(fromDE, "/")

internal/discriminator/dnsbl.go

@@ -5,13 +5,16 @@ package discriminator
 
 import (
 	"context"
+	"strings"
 	"time"
 
+	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 )
 
 // dnsbl notes the DNSBL zones whose verdict lists the client, as noteListed
-// does, and refuses the request when SWW_REPUTATION_ACTION is deny. Being
+// does, adds the tag dnsbl=<zone> for each, the zone's key masked, and refuses
+// the request when SWW_REPUTATION_ACTION is deny. Being
 // limit, it lowers the client's limits instead (see limitPercentages), and
 // being log, it does nothing more. A zone without a verdict on the client is
 // asked about it in the background, and the request does not wait for the
@@ -25,6 +28,10 @@ func (dnsbl) check(ctx context.Context, rq *request, _ time.Time) *verdict {
 	rq.dnsblListed = len(listedBy) > 0
 	rq.noteListed(listedBy, "listed by a DNSBL zone")
 
+	for _, zone := range listedBy {
+		rq.addTag(config.DNSBLTagPrefix + strings.ToLower(zone))
+	}
+
 	if !rq.dnsblListed || rq.h.config.ReputationAction != deny {
 		return nil
 	}

internal/discriminator/heuristics.go

@@ -43,12 +43,15 @@ const (
 // country are looked up, so that a client they refuse is not looked up.
 func beforeLookup() []heuristic {
 	return []heuristic{
+		tagLists{},
 		denyNets{},
 		activeBan{},
 	}
 }
 
 // afterLookup are the heuristics that run once the lookup has been made.
+// tag_deny runs twice: before the rate limits, on the tags known by then, and
+// last, on the tag rule_files and core_rule_set can add.
 func afterLookup() []heuristic {
 	return []heuristic{
 		countries{},
@@ -56,11 +59,13 @@ func afterLookup() []heuristic {
 		crowdSec{},
 		dnsbl{},
 		abuseIPDB{},
+		tagDeny{},
 		rateLimits{},
 		trapPaths{},
 		ruleFiles{},
 		headerLimits{},
 		coreRuleSet{},
+		tagDeny{},
 	}
 }
 

internal/discriminator/history_test.go

@@ -20,7 +20,7 @@ func TestHistoryKeepsEachRequestOfTheClient(t *testing.T) {
 	s, clk, server := startWithClock(t, geojsURL, map[string]string{
 		lookupTimeout:      "1h",
 		rateLimitPerMinute: "2",
-		deniedCountries:    "kp",
+		tagDeny:            denyKP,
 	})
 	start := clk.Now()
 

internal/discriminator/lookup.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"net/http"
 	"net/netip"
+	"strings"
 	"time"
 
+	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
 )
 
@@ -19,7 +21,8 @@ const (
 )
 
 // lookUp looks up the client's AS number and country, in the lookup
-// database or through GeoJS, and notes them for the log line, unless
+// database or through GeoJS, and notes them for the log line and as the
+// request's asn= and country= tags, unless
 // SWW_LOOKUP_SOURCE is off or the client is on a private, loopback or
 // link-local address, which no lookup can place. The lookup database
 // answers at once. With GeoJS, while a setting needs the answer, such as a
@@ -47,6 +50,34 @@ func (rq *request) lookUp(ctx context.Context, now time.Time) {
 	rq.line.ASN = rq.lookupAnswer.ASN
 	rq.line.ASName = rq.lookupAnswer.ASName
 	rq.line.Country = rq.lookupAnswer.Country
+
+	if tag := asnTag(rq.line.ASN); tag != "" {
+		rq.addTag(tag)
+	}
+
+	if tag := countryTag(rq.line.Country); tag != "" {
+		rq.addTag(tag)
+	}
+}
+
+// asnTag returns the tag of asn, an AS number as the lookup gives it, such as
+// asn=64496 for AS64496, or "" for no AS number.
+func asnTag(asn string) string {
+	if asn == "" {
+		return ""
+	}
+
+	return config.ASNTagPrefix + strings.TrimPrefix(asn, "AS")
+}
+
+// countryTag returns the tag of country, a code as the lookup gives it, such
+// as country=DE for DE, or "" for no country.
+func countryTag(country string) string {
+	if country == "" {
+		return ""
+	}
+
+	return config.CountryTagPrefix + country
 }
 
 // addLookup adds answer, an answer about a client from the lookup

internal/discriminator/lookup_test.go

@@ -96,7 +96,7 @@ func TestRequestThatWaitedForItsLookupIsCountedWhenItGoesOn(t *testing.T) {
 		map[string]string{
 			trustedProxies: trustLocalhost,
 			lookupTimeout:  "1h",
-			deniedCountries: "kp",
+			tagDeny:        denyKP,
 		})
 
 	requestFromDE := func() *http.Request {

internal/discriminator/metrics_test.go

@@ -198,7 +198,7 @@ func TestMetricsByCountryKeepTheBusiestAndCountTheRestAsOther(t *testing.T) {
 		trustedProxies:   trustLocalhost,
 		metricsToken:     token,
 		metricsTopN:      "2",
-		deniedCountries: "kp",
+		allowedCountries: "de,fr",
 	}
 	geojsURL, _ := startGeoJS(t)
 	addr, out, server := startProxyWithClock(t, app.URL, geojsURL, time.Now, env)
@@ -324,11 +324,11 @@ func TestMetricsCountGeoJSRequestsAndFailures(t *testing.T) {
 		map[string]string{
 			trustedProxies: trustLocalhost,
 			metricsToken:   token,
-			deniedCountries: "kp",
+			tagDeny:        denyKP,
 		})
 
-	// GeoJS fails, so the client counts as coming from an unknown country,
-	// which SWW_DENIED_COUNTRIES does not refuse.
+	// GeoJS fails, so the client has no country= tag, and SWW_TAG_DENY does
+	// not refuse it.
 	req := newRequest(t, http.MethodGet, addr, "/", http.NoBody)
 	req.Header.Set(forwardedFor, fromDE)
 	wantStatus(t, do(t, req), http.StatusOK)

internal/discriminator/observe_test.go

@@ -50,7 +50,7 @@ func TestObserveModeForwardsWhatEnforceModeRefuses(t *testing.T) {
 				lookupTimeout:      "1h",
 				rateLimitPerMinute: "1",
 				denyNets:           denied,
-				deniedCountries:    "kp",
+				tagDeny:            denyKP,
 			}
 
 			if tc.setting != "" {
@@ -71,7 +71,7 @@ func TestObserveModeForwardsWhatEnforceModeRefuses(t *testing.T) {
 			for _, sent := range []struct{ from, refusal string }{
 				{denied, requestlog.ActionDenied},
 				{banned, requestlog.ActionBanned},
-				{fromKP, requestlog.ActionCountryDenied},
+				{fromKP, requestlog.ActionDenied},
 				{fromDE, requestlog.ActionRateLimited},
 			} {
 				if !tc.observe {

internal/discriminator/proxy.go

@@ -155,11 +155,12 @@ func newHandler(params Params) *handler {
 	h.geojs = lookup.New(lookup.Params{
 		URL:     params.GeoJSURL,
 		Timeout: params.Config.LookupTimeout,
-		// The country lists, the headers and the biased thresholds act on
-		// the answer before the request goes on.
-		Wait: len(params.Config.DeniedCountries) > 0 ||
-			len(params.Config.ExclusivelyAllowedCountries) > 0 ||
-			params.Config.AddLookupHeaders || biasedThresholdsSet(params.Config),
+		// The country list, the headers, the tag settings that name an asn=
+		// or country= tag and the biased thresholds act on the answer before
+		// the request goes on.
+		Wait: len(params.Config.ExclusivelyAllowedCountries) > 0 ||
+			params.Config.AddLookupHeaders || params.Config.TagsNeedLookup() ||
+			biasedThresholdsSet(params.Config),
 		Answered:   h.addLookup,
 		Now:        params.Now,
 		ProcessLog: params.ProcessLog,
@@ -183,6 +184,7 @@ func newReputation(
 	lists := reputation.New(reputation.Params{
 		BlocklistURLs: cfg.BlocklistURLs, Refresh: cfg.BlocklistRefresh,
 		ASNLimitPercentURL:   cfg.ASNLimitPercentURL,
+		TagLists:             cfg.TagLists,
 		CrowdSecDecisionsURL: cfg.CrowdSecDecisionsURL, CrowdSecKey: cfg.CrowdSecKey,
 		Now: params.Now, ProcessLog: params.ProcessLog, Alerts: params.Alerts,
 	})

internal/discriminator/proxy_test.go

@@ -69,7 +69,9 @@ const (
 	lookupDBPath         = "SWW_LOOKUP_DB_PATH"
 	lookupTimeout        = "SWW_LOOKUP_TIMEOUT"
 	addLookupHeaders     = "SWW_ADD_LOOKUP_HEADERS"
-	deniedCountries      = "SWW_DENIED_COUNTRIES"
+	tagDeny              = "SWW_TAG_DENY"
+	// denyKP is the value of SWW_TAG_DENY that refuses fromKP's country.
+	denyKP               = "country=KP"
 	allowedCountries     = "SWW_EXCLUSIVELY_ALLOWED_COUNTRIES"
 	banResponse          = "SWW_BAN_RESPONSE"
 	limitBanDuration     = "SWW_LIMIT_BAN_DURATION"

internal/discriminator/ratelimits_test.go

@@ -136,7 +136,7 @@ func TestRateLimitExemptPathsAreNeitherCountedNorRefused(t *testing.T) {
 		rateLimitPerMinute:   "1",
 		rateLimitExemptPaths: "/assets/,/favicon.ico",
 		denyNets:             denied,
-		deniedCountries:      "kp",
+		tagDeny:              denyKP,
 	})
 
 	// The answers are kept before the requests, so that none waits for
@@ -162,12 +162,12 @@ func TestRateLimitExemptPathsAreNeitherCountedNorRefused(t *testing.T) {
 	// /assets/, and breaks the limit.
 	s.request(client, "/assets", http.StatusForbidden, requestlog.ActionRateLimited)
 
-	// A ban, SWW_DENY_NETS and the country lists still refuse a path
-	// under a prefix.
+	// A ban, SWW_DENY_NETS and SWW_TAG_DENY 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)
+		http.StatusForbidden, requestlog.ActionDenied)
 }
 
 func TestRateLimitCountsPathsThatAreNotExempt(t *testing.T) {

internal/discriminator/refusallimit_test.go

@@ -191,7 +191,7 @@ func TestErrorBurstIsNotLoweredForAClientWithLowerLimits(t *testing.T) {
 		lookupTimeout:       "1h",
 		errorBurstThreshold: "2",
 		rulesDir:            writeRules(t, testRules),
-		countryLimitPercent: countryDEHalf,
+		tagLimitPercent:     countryTagDEHalf,
 	})
 
 	// Half of the threshold would be one, which the second refusal is over.

internal/discriminator/reputation_test.go

@@ -168,11 +168,11 @@ func TestReputationRefusalNamesItsHeuristicAndWhatListedTheClient(t *testing.T)
 	}
 }
 
-func TestBlocklistsComeAfterTheCountryListsAndSkipAllowNets(t *testing.T) {
+func TestBlocklistsComeAfterAllowedCountriesAndSkipAllowNets(t *testing.T) {
 	t.Parallel()
 
 	s, server, queue := startWithLookups(t, map[string]string{
-		blocklistURLs: dropURL, deniedCountries: "kp", allowNets: fromDE,
+		blocklistURLs: dropURL, allowedCountries: "de", allowNets: fromDE,
 	})
 	loadLists(t, server, map[string][]string{dropURL: {fromDE, fromKP}})
 
@@ -211,18 +211,18 @@ func TestBlocklistLimitTakesPartInTheLowestPercentageOfEveryLimit(t *testing.T)
 		// percentText gives them, and limitHit its limit_hit.
 		want, limitHit string
 	}{
-		{limitHalf, asnDEQuarter, "25 from " + asnLimitPercent, minuteBytes},
-		{limitQuarter, asnDEHalf, "25 from " + blocklistAction, minuteBytes},
+		{limitHalf, asnTagDEQuarter, "25 from " + tagLimitPercent, minuteBytes},
+		{limitQuarter, asnTagDEHalf, "25 from " + blocklistAction, minuteBytes},
 		// The AS number's, the first of two alike.
-		{limitQuarter, asnDEQuarter, "25 from " + asnLimitPercent, minuteBytes},
-		{actionLog, asnDE + ":100", none, ""},
+		{limitQuarter, asnTagDEQuarter, "25 from " + tagLimitPercent, minuteBytes},
+		{actionLog, "asn=64511:25", none, ""},
 	} {
 		t.Run(tc.action+" "+tc.asnPercent, func(t *testing.T) {
 			t.Parallel()
 
 			s, server, _ := startWithLookups(t, map[string]string{
 				bytesLimitPerMinute: twoUploads, blocklistURLs: dropURL,
-				blocklistAction: tc.action, asnLimitPercent: tc.asnPercent,
+				blocklistAction: tc.action, tagLimitPercent: tc.asnPercent,
 			})
 			loadLists(t, server, map[string][]string{dropURL: {fromDE}})
 
@@ -246,7 +246,7 @@ func TestASNLimitPercentFileCountsAsTheSettingDoesTheLowerWinning(t *testing.T)
 
 	const (
 		fromURL     = "25 from " + asnLimitPercentURL
-		fromSetting = "25 from " + asnLimitPercent
+		fromSetting = "25 from " + tagLimitPercent
 	)
 
 	for _, tc := range []struct {
@@ -260,16 +260,16 @@ func TestASNLimitPercentFileCountsAsTheSettingDoesTheLowerWinning(t *testing.T)
 		{"the file's alone", nil, asnDEQuarter, fromURL, fromURL},
 		{
 			"the file's, lower than the setting's",
-			map[string]string{asnLimitPercent: asnDEHalf}, asnDEQuarter, fromURL, fromURL,
+			map[string]string{tagLimitPercent: asnTagDEHalf}, asnDEQuarter, fromURL, fromURL,
 		},
 		{
 			"the setting's, lower than the file's",
-			map[string]string{asnLimitPercent: asnDEQuarter}, asnDEHalf,
+			map[string]string{tagLimitPercent: asnTagDEQuarter}, asnDEHalf,
 			fromSetting, fromSetting,
 		},
 		{
 			"the setting's, the first of two alike",
-			map[string]string{asnLimitPercent: asnDEQuarter}, asnDEQuarter,
+			map[string]string{tagLimitPercent: asnTagDEQuarter}, asnDEQuarter,
 			fromSetting, fromSetting,
 		},
 		{"none, for an AS number the file does not list", nil, asnKP + ":25", none, none},
@@ -482,6 +482,46 @@ func TestDNSBLZonesComeAfterTheBlocklistsAndSkipAllowNets(t *testing.T) {
 	}
 }
 
+func TestReputationSourcesTagTheRequestWhateverTheirAction(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range []struct {
+		name string
+		env  map[string]string
+		load func(*discriminator.Server)
+		want []string
+	}{
+		{
+			"dnsbl",
+			map[string]string{
+				dnsblZones: dnsblZone, dnsblResolver: noResolver, reputationAction: actionLog,
+			},
+			func(server *discriminator.Server) {
+				loadVerdicts(server, map[string][]string{fromDE: {dnsblZone}})
+			},
+			[]string{"asn=64496", "country=DE", "dnsbl=" + dnsblZone},
+		},
+		{
+			abuseipdb,
+			map[string]string{abuseIPDBKey: accountKey, reputationAction: actionLog},
+			func(server *discriminator.Server) {
+				loadScores(server, map[string]int64{fromDE: 80})
+			},
+			[]string{abuseipdb, "asn=64496", "country=DE"},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			s, server, _ := startWithLookups(t, tc.env)
+			tc.load(server)
+
+			wantTags(t, s.get(fromDE, http.StatusOK, requestlog.ActionForward),
+				tc.want...)
+		})
+	}
+}
+
 func TestObserveModeForwardsAClientADNSBLZoneDeniesAndAlertsIt(t *testing.T) {
 	t.Parallel()
 

internal/discriminator/request.go

@@ -138,6 +138,15 @@ func (h *handler) startRequest(
 	return rq
 }
 
+// addTag adds tag to the request's tags, which stay sorted and hold each tag
+// once.
+func (rq *request) addTag(tag string) {
+	at, found := slices.BinarySearch(rq.line.Tags, tag)
+	if !found {
+		rq.line.Tags = slices.Insert(rq.line.Tags, at, tag)
+	}
+}
+
 // 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.

internal/discriminator/rulefiles.go

@@ -8,12 +8,14 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
 )
 
 // ruleFiles checks the request against the rules of the rule files at now,
-// notes the ids of those it matches in the log line, and refuses the request
+// notes the ids of those it matches in the log line, adds the tag
+// exploitsignature when it matches any, and refuses the request
 // when the last rule it matches refuses it: with ActionRuleBlocked for a block
 // rule, and ActionBanned for a ban rule. A ban rule bans the client's netblock
 // for a clear sign of attack, or in observe mode raises the alert for the ban
@@ -35,6 +37,8 @@ func (ruleFiles) check(_ context.Context, rq *request, now time.Time) *verdict {
 		return nil
 	}
 
+	rq.addTag(config.ExploitSignatureTag)
+
 	// Only the last rule matched can refuse the request.
 	last := matched[len(matched)-1]
 	figures := map[string]any{"rule_id": last.ID, "rule_action": last.Action}

internal/discriminator/rulefiles_test.go

@@ -93,6 +93,20 @@ func TestEachRuleAction(t *testing.T) {
 	s.get(client, http.StatusTooManyRequests, requestlog.ActionBanned)
 }
 
+func TestEachRuleActionAddsTheExploitSignatureTag(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{
+		rulesDir: writeRules(t, "noted path log ^/noted$\n"+testRules),
+	})
+
+	wantTags(t, s.request(client, "/noted", http.StatusOK, requestlog.ActionForward),
+		"exploitsignature")
+	wantTags(t, s.request(client, "/blocked", http.StatusForbidden,
+		requestlog.ActionRuleBlocked), "exploitsignature")
+	wantTags(t, s.get(client, http.StatusOK, requestlog.ActionForward))
+}
+
 func TestRuleRefusalNamesItsHeuristicAndTheRule(t *testing.T) {
 	t.Parallel()
 

internal/discriminator/staticlists_test.go

@@ -32,13 +32,12 @@ func TestAllowNetsSkipEveryCheck(t *testing.T) {
 		trustedProxies:     trustLocalhost,
 		allowNets:          "198.51.100.0/24",
 		denyNets:           fromKP,
-		deniedCountries:    "kp",
+		tagDeny:            denyKP,
 		rateLimitPerMinute: "1",
 	})
 
-	// Neither SWW_DENY_NETS, the country lists nor the limit of one
-	// request a minute refuses the client, and its country is not looked
-	// up.
+	// Neither SWW_DENY_NETS, SWW_TAG_DENY 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},
@@ -85,7 +84,7 @@ func TestDenyNetsRefuseBeforeTheLookup(t *testing.T) {
 	addr, out := startProxyWithGeoJS(t, app.URL, geojsURL, map[string]string{
 		trustedProxies: trustLocalhost,
 		denyNets:       "203.0.113.0/24",
-		deniedCountries: "kp",
+		tagDeny:        denyKP,
 	})
 
 	req := newRequest(t, http.MethodPost, addr, "/", strings.NewReader("a body"))
@@ -142,19 +141,19 @@ func TestRateLimitExemptNetsAreNeitherCountedNorRefused(t *testing.T) {
 		trustedProxies:      trustLocalhost,
 		lookupTimeout:       "1h",
 		rateLimitExemptNets: listedAddr + "," + fromKP,
-		deniedCountries:     "kp",
+		tagDeny:             denyKP,
 		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.
+	// request from unlistedAddr is within the limit of one a minute.
+	// SWW_TAG_DENY still refuses 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},
+		{fromKP, http.StatusForbidden, requestlog.ActionDenied},
 	})
 }
 

internal/discriminator/tagdeny.go

@@ -0,0 +1,30 @@
+package discriminator
+
+// The heuristic tag_deny. It reads SWW_TAG_DENY.
+
+import (
+	"context"
+	"slices"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// tagDeny refuses a request that carries a tag in SWW_TAG_DENY. Its figure is
+// the first such tag, in sorted order.
+type tagDeny struct{}
+
+func (tagDeny) name() string { return "tag_deny" }
+
+func (tagDeny) check(_ context.Context, rq *request, _ time.Time) *verdict {
+	for _, tag := range rq.line.Tags {
+		if slices.Contains(rq.h.config.TagDeny, tag) {
+			return &verdict{
+				action:  requestlog.ActionDenied,
+				figures: map[string]any{"tag": tag},
+			}
+		}
+	}
+
+	return nil
+}

internal/discriminator/tagdeny_test.go

@@ -0,0 +1,121 @@
+package discriminator_test
+
+import (
+	"net/http"
+	"testing"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+func TestTagDenyRefusesALookupTagAndNamesTheTag(t *testing.T) {
+	t.Parallel()
+
+	// The setting takes a country code in either case; the request's tag is
+	// in capitals.
+	s, _, _ := startWithLookups(t, map[string]string{tagDeny: "Country=kp"})
+
+	line := s.get(fromKP, http.StatusForbidden, requestlog.ActionDenied)
+	wantHeuristic(t, line, "tag_deny", `{"tag": "country=KP"}`)
+	wantTags(t, line, "asn=64511", "country=KP")
+
+	s.get(fromDE, http.StatusOK, requestlog.ActionForward)
+}
+
+func TestTagDenyRefusesAnASNTag(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithLookups(t, map[string]string{tagDeny: "asn=64511"})
+
+	wantHeuristic(t, s.get(fromKP, http.StatusForbidden, requestlog.ActionDenied),
+		"tag_deny", `{"tag": "asn=64511"}`)
+	s.get(fromDE, http.StatusOK, requestlog.ActionForward)
+}
+
+func TestTagDenyRefusesAListTagBeforeTheRateLimitsCount(t *testing.T) {
+	t.Parallel()
+
+	s, server, _ := startWithLookups(t, map[string]string{
+		tagLists: "torexit=" + torList, tagDeny: "torexit", rateLimitPerMinute: "1",
+	})
+	loadLists(t, server, map[string][]string{torList: {fromDE}})
+
+	// Each is refused for its tag: none is counted to break the limit of one.
+	for range 3 {
+		wantHeuristic(t, s.get(fromDE, http.StatusForbidden, requestlog.ActionDenied),
+			"tag_deny", `{"tag": "torexit"}`)
+	}
+}
+
+func TestTagDenyRefusesAMixedCaseZoneByItsLowerCaseTag(t *testing.T) {
+	t.Parallel()
+
+	const mixedCaseZone = "DNSBL.example"
+
+	// The zone's tag is in lower case, however SWW_DNSBL_ZONES writes it.
+	s, server, _ := startWithLookups(t, map[string]string{
+		dnsblZones: mixedCaseZone, dnsblResolver: noResolver,
+		reputationAction: actionLog, tagDeny: "dnsbl=" + dnsblZone,
+	})
+	loadVerdicts(server, map[string][]string{fromDE: {mixedCaseZone}})
+
+	wantHeuristic(t, s.get(fromDE, http.StatusForbidden, requestlog.ActionDenied),
+		"tag_deny", `{"tag": "dnsbl=`+dnsblZone+`"}`)
+}
+
+func TestTagDenyRefusesAnExploitSignatureOfARuleThatOnlyLogs(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{
+		rulesDir: writeRules(t, "noted path log ^/\n"), tagDeny: "exploitsignature",
+	})
+
+	line := s.get(client, http.StatusForbidden, requestlog.ActionDenied)
+	wantHeuristic(t, line, "tag_deny", `{"tag": "exploitsignature"}`)
+	wantTags(t, line, "exploitsignature")
+}
+
+func TestTagLimitPercentLowersALimitTheLowestWinning(t *testing.T) {
+	t.Parallel()
+
+	s, server, _ := startWithLookups(t, map[string]string{
+		rateLimitPerMinute: fourAMinute,
+		tagLists:           "vpn=" + vpnList + ",tor=" + torList,
+		tagLimitPercent:    "vpn:50,tor:25",
+	})
+	loadLists(t, server, map[string][]string{vpnList: {fromDE}, torList: {fromDE}})
+
+	// A quarter of 4 requests a minute: the second breaks the limit.
+	s.get(fromDE, http.StatusOK, requestlog.ActionForward)
+
+	line := s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
+	wantPercent(t, "limit_percent", line.LimitPercent, line.LimitPercentSetting,
+		"25 from "+tagLimitPercent)
+}
+
+func TestTagLimitPercentLowersAByteLimitByAListTag(t *testing.T) {
+	t.Parallel()
+
+	s, server, _ := startWithLookups(t, map[string]string{
+		bytesLimitPerMinute: twoUploads,
+		tagLists:            "vpn=" + vpnList,
+		tagLimitPercent:     "vpn:50",
+	})
+	loadLists(t, server, map[string][]string{vpnList: {fromDE}})
+
+	// The upload's 100 bytes are over half of 199, 99.
+	line := s.uploadFrom(fromDE)
+	if line.LimitHit != minuteBytes {
+		t.Errorf("log line has limit_hit %q, want %s", line.LimitHit, minuteBytes)
+	}
+
+	wantPercent(t, "bytes_percent", line.BytesPercent, line.BytesPercentSetting,
+		"50 from "+tagLimitPercent)
+
+	// fromKP, which the list does not hold, has the whole limit.
+	line = s.uploadFrom(fromKP)
+	if line.LimitHit != "" {
+		t.Errorf("log line for %s has limit_hit %q, want none", fromKP, line.LimitHit)
+	}
+
+	wantPercent(t, "bytes_percent", line.BytesPercent, line.BytesPercentSetting, none)
+}

internal/discriminator/taglists.go

@@ -0,0 +1,24 @@
+package discriminator
+
+// The heuristic tag_lists. It reads the address lists of SWW_TAG_LISTS through
+// the reputation lists.
+
+import (
+	"context"
+	"time"
+)
+
+// tagLists adds to the request one tag for each list of SWW_TAG_LISTS that
+// holds the client, the tag being the list's name. It refuses nothing, and runs
+// first so that every refusal's log line carries these tags.
+type tagLists struct{}
+
+func (tagLists) name() string { return "tag_lists" }
+
+func (tagLists) check(_ context.Context, rq *request, _ time.Time) *verdict {
+	for _, name := range rq.h.lists.TagsOf(rq.client) {
+		rq.addTag(name)
+	}
+
+	return nil
+}

internal/discriminator/taglists_test.go

@@ -0,0 +1,100 @@
+package discriminator_test
+
+import (
+	"net/http"
+	"slices"
+	"testing"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// tagLists is SWW_TAG_LISTS, and vpnList and torList lists it names.
+const (
+	tagLists = "SWW_TAG_LISTS"
+	vpnList  = "https://lists.example/vpn.txt"
+	torList  = "https://lists.example/torexit.txt"
+)
+
+// wantTags checks the log line's tags.
+func wantTags(t *testing.T, line logLine, want ...string) {
+	t.Helper()
+
+	got, _ := line.fields["tags"].([]any)
+
+	tags := make([]string, 0, len(got))
+	for _, tag := range got {
+		text, _ := tag.(string)
+		tags = append(tags, text)
+	}
+
+	if !slices.Equal(tags, want) {
+		t.Errorf("log line has tags %v, want %v", tags, want)
+	}
+}
+
+func TestLookupAndTagListsGiveTheRequestItsTagsSorted(t *testing.T) {
+	t.Parallel()
+
+	s, server, _ := startWithLookups(t, map[string]string{
+		tagLists: "vpn=mullvad=" + vpnList + ",TorExit=" + torList,
+	})
+	loadLists(t, server, map[string][]string{
+		vpnList: {fromDE}, torList: {fromDE + "/32", fromKP},
+	})
+
+	wantTags(t, s.get(fromDE, http.StatusOK, requestlog.ActionForward),
+		"asn=64496", "country=DE", "torexit", "vpn=mullvad")
+	wantTags(t, s.get(fromKP, http.StatusOK, requestlog.ActionForward),
+		"asn=64511", "country=KP", "torexit")
+}
+
+func TestRequestWithoutATagLeavesTheFieldOut(t *testing.T) {
+	t.Parallel()
+
+	// With no lookup, a client is not placed and no setting gives it a tag.
+	s, _, _ := startWithClock(t, "", map[string]string{lookupSource: "off"})
+
+	line := s.get(fromDE, http.StatusOK, requestlog.ActionForward)
+	if _, present := line.fields["tags"]; present {
+		t.Errorf("log line has tags %v, want none", line.fields["tags"])
+	}
+}
+
+func TestTagListsTagEvenARequestTheCountryListRefuses(t *testing.T) {
+	t.Parallel()
+
+	s, server, _ := startWithLookups(t, map[string]string{
+		tagLists: "vpn=" + vpnList, allowedCountries: "de",
+	})
+	loadLists(t, server, map[string][]string{vpnList: {fromKP}})
+
+	wantTags(t, s.get(fromKP, http.StatusForbidden, requestlog.ActionCountryDenied),
+		"asn=64511", "country=KP", "vpn")
+}
+
+func TestTagListsTagARequestRefusedBeforeTheLookup(t *testing.T) {
+	t.Parallel()
+
+	s, server, _ := startWithLookups(t, map[string]string{
+		tagLists: "vpn=" + vpnList, denyNets: fromKP, rateLimitPerMinute: "1",
+	})
+	loadLists(t, server, map[string][]string{vpnList: {fromDE, fromKP}})
+
+	line := s.get(fromKP, http.StatusForbidden, requestlog.ActionDenied)
+	if line.Heuristic != "deny_nets" {
+		t.Errorf("log line has heuristic %q, want deny_nets", line.Heuristic)
+	}
+
+	wantTags(t, line, "vpn")
+
+	// The second request breaks the limit of one a minute, which bans the client.
+	s.get(fromDE, http.StatusOK, requestlog.ActionForward)
+	s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
+
+	line = s.get(fromDE, http.StatusForbidden, requestlog.ActionBanned)
+	if line.Heuristic != "active_ban" {
+		t.Errorf("log line has heuristic %q, want active_ban", line.Heuristic)
+	}
+
+	wantTags(t, line, "vpn")
+}

internal/metrics/busiest.go

@@ -25,7 +25,7 @@ type busiest struct {
 	requests      *prometheus.CounterVec
 	requestBytes  *prometheus.CounterVec
 	responseBytes *prometheus.CounterVec
-	// refused are, by country, the requests the country lists refused; nil
+	// refused are, by country, the requests the country list refused; nil
 	// by AS number.
 	refused *prometheus.CounterVec
 
@@ -42,7 +42,7 @@ type busiest struct {
 func newCountries(topN int) *busiest {
 	countries := newBusiest(topN, "country", "the client's country")
 	countries.refused = counterVec("sww_country_list_refusals_total",
-		"Requests the country lists refused, by the client's country.",
+		"Requests SWW_EXCLUSIVELY_ALLOWED_COUNTRIES refused, by the client's country.",
 		[]string{"country"})
 
 	return countries
@@ -88,7 +88,7 @@ func (b *busiest) Collect(ch chan<- prometheus.Metric) {
 }
 
 // vecs returns the metrics: by AS number, those of requests and bytes; by
-// country, the refusals by the country lists as well.
+// country, the refusals by the country list as well.
 func (b *busiest) vecs() []*prometheus.CounterVec {
 	vecs := []*prometheus.CounterVec{b.requests, b.requestBytes, b.responseBytes}
 	if b.refused != nil {

internal/reputation/reputation.go

@@ -1,7 +1,8 @@
 // Package reputation fetches the lists the settings name by URL: the
 // blocklists of SWW_BLOCKLIST_URLS, the file of AS:percent lines
-// SWW_ASN_LIMIT_PERCENT_URL names, and the decision list of the CrowdSec
-// engine SWW_CROWDSEC_LAPI_URL names. It keeps the last good copy of
+// SWW_ASN_LIMIT_PERCENT_URL names, the address lists of SWW_TAG_LISTS, and
+// the decision list of the CrowdSec engine SWW_CROWDSEC_LAPI_URL names. It
+// keeps the last good copy of
 // each, whole, comment lines included, which is used while a fetch fails,
 // and when each was last tried. It also asks the DNSBL zones of
 // SWW_DNSBL_ZONES about clients, and keeps their verdicts, and checks
@@ -71,6 +72,8 @@ type Params struct {
 	// (SWW_ASN_LIMIT_PERCENT_URL), "" while it is unset.
 	BlocklistURLs      []string
 	ASNLimitPercentURL string
+	// TagLists are the address lists that add a tag (SWW_TAG_LISTS).
+	TagLists []config.TagList
 	// CrowdSecDecisionsURL is the CrowdSec decision list, "" while
 	// SWW_CROWDSEC_LAPI_URL is unset, fetched with CrowdSecKey
 	// (SWW_CROWDSEC_LAPI_KEY).
@@ -112,11 +115,11 @@ type list struct {
 	failures int
 }
 
-// entries are what the lines of a copy say: for a blocklist, the netblocks
-// it names, with the lengths among them, for the file of AS:percent lines,
-// the percentage it gives each AS number, and for the CrowdSec decision
-// list, the decision on each netblock that ends last, with the lengths
-// among them.
+// entries are what the lines of a copy say: for a blocklist or a tag list, the
+// netblocks it names, with the lengths among them, for the file of AS:percent
+// lines, the percentage it gives each AS number, and for the CrowdSec decision
+// list, the decision on each netblock that ends last, with the lengths among
+// them.
 type entries struct {
 	netblocks map[netip.Prefix]bool
 	lengths   []int
@@ -152,14 +155,18 @@ func New(params Params) *Lists {
 }
 
 // URLs returns the URL of every list: the blocklists' in the order
-// SWW_BLOCKLIST_URLS names them, then SWW_ASN_LIMIT_PERCENT_URL, then
-// the CrowdSec decision list's.
+// SWW_BLOCKLIST_URLS names them, then SWW_ASN_LIMIT_PERCENT_URL, then the
+// tag lists', then the CrowdSec decision list's.
 func (l *Lists) URLs() []string {
 	urls := slices.Clone(l.params.BlocklistURLs)
 	if l.params.ASNLimitPercentURL != "" {
 		urls = append(urls, l.params.ASNLimitPercentURL)
 	}
 
+	for _, list := range l.params.TagLists {
+		urls = append(urls, list.URL)
+	}
+
 	if l.params.CrowdSecDecisionsURL != "" {
 		urls = append(urls, l.params.CrowdSecDecisionsURL)
 	}
@@ -184,6 +191,22 @@ func (l *Lists) ListedBy(addr netip.Addr) []string {
 	return listedBy
 }
 
+// TagsOf returns the names of the tag lists whose copy holds addr.
+func (l *Lists) TagsOf(addr netip.Addr) []string {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	var names []string
+
+	for _, list := range l.params.TagLists {
+		if l.lists[list.URL].entries.contain(addr) {
+			names = append(names, list.Name)
+		}
+	}
+
+	return names
+}
+
 // ASNLimitPercent returns the percentage the copy of the file of
 // AS:percent lines gives asn, and whether it lists asn.
 func (l *Lists) ASNLimitPercent(asn string) (int64, bool) {
@@ -481,10 +504,10 @@ func (l *Lists) get(ctx context.Context, listURL string) ([]string, error) {
 }
 
 // parse reads the lines of the list at listURL, fetched at fetched: those
-// of a blocklist, of the file of AS:percent lines, or of the CrowdSec
-// decision list. In the first two, anything after a ; or a # on a line is
-// left out, and so is a line left blank. Any other line that does not read
-// is an error naming it by its number.
+// of a blocklist or a tag list, of the file of AS:percent lines, or of the
+// CrowdSec decision list. In all but the decision list, anything after a ; or
+// a # on a line is left out, and so is a line left blank. Any other line that
+// does not read is an error naming it by its number.
 func (l *Lists) parse(
 	listURL string, lines []string, fetched time.Time,
 ) (entries, error) {
@@ -498,8 +521,8 @@ func (l *Lists) parse(
 	}
 }
 
-// parseNetblocks reads a blocklist's lines, each an address or a netblock
-// as the settings take them.
+// parseNetblocks reads the lines of a blocklist or a tag list, each an address
+// or a netblock as the settings take them.
 func parseNetblocks(lines []string) (entries, error) {
 	found := entries{netblocks: map[netip.Prefix]bool{}}
 
@@ -551,7 +574,7 @@ func parseNetblock(text string) (netip.Prefix, bool) {
 }
 
 // parsePercents reads the lines of the file of AS:percent lines, each an
-// AS number, : and a percentage, as SWW_ASN_LIMIT_PERCENT takes them. An
+// AS number, : and a percentage, such as AS64496:50. An
 // AS number listed more than once gets the lowest of its percentages.
 func parsePercents(lines []string) (entries, error) {
 	found := entries{percents: map[string]int64{}}

internal/requestlog/requestlog.go

@@ -44,10 +44,11 @@ const (
 	// ActionDenied is a request refused because its client is in
 	// SWW_DENY_NETS, in a blocklist while SWW_BLOCKLIST_ACTION is deny,
 	// or listed by a DNSBL zone, or scored a hit by AbuseIPDB, while
-	// SWW_REPUTATION_ACTION is deny.
+	// SWW_REPUTATION_ACTION is deny, or that carries a tag in SWW_TAG_DENY.
 	ActionDenied = "denied"
 
-	// ActionCountryDenied is a request refused for its client's country.
+	// ActionCountryDenied is a request refused because its client's country
+	// is not in SWW_EXCLUSIVELY_ALLOWED_COUNTRIES.
 	ActionCountryDenied = "country_denied"
 	// ActionAdmin is a request discriminator answered at one of its own
 	// endpoints, or a question about a path under /_sww/.
@@ -179,6 +180,8 @@ type Line struct {
 	// whose verdict lists it, their keys masked, then abuseipdb when its
 	// score is a hit.
 	Reputation []string `json:"reputation,omitempty"`
+	// Tags are the request's tags, sorted.
+	Tags []string `json:"tags,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,

internal/sww/sww_test.go

@@ -618,7 +618,7 @@ func TestLookupDatabaseReplacedWhileRunningTakesEffect(t *testing.T) {
 		instanceName:   instance,
 		lookupSource:   "file",
 		lookupDBPath:   path,
-		"SWW_DENIED_COUNTRIES": "kp",
+		"SWW_TAG_DENY": "country=KP",
 		// The requests sent until a replacement takes effect, and those
 		// for the metrics, must not break a rate limit, whose ban would
 		// refuse them too.
@@ -1280,7 +1280,7 @@ func wantStartingLine(t *testing.T, line map[string]any, dir string) {
 		"SWW_RATE_LIMIT_PER_HOUR":           "1500",
 		rateLimitPerDay:                     "6000",
 		"SWW_RATE_LIMIT_EXEMPT_PATHS":       "",
-		"SWW_DENIED_COUNTRIES":              "",
+		"SWW_TAG_DENY":                      "",
 		"SWW_EXCLUSIVELY_ALLOWED_COUNTRIES": "",
 		"SWW_BAN_RESPONSE":                  "403",
 		"SWW_LIMIT_BAN_DURATION":            "1h",