smallwebwaf/docs/gitea.md

# smallwebwaf in front of gitea

These notes record what `smallwebwaf` does in front of gitea at the default
settings. They are observations, not requirements; the requirements are in
[`SPEC.md`](../SPEC.md). `script/gitea-requests` runs gitea behind the image and
sends through it a sample of gitea's ordinary use and the requests named below.
It reports each request the Core Rule Set refuses, so that these notes can be
checked again when gitea or the Core Rule Set changes version.

## What the defaults cover

- SSH access to gitea does not pass through `smallwebwaf` and is not protected
  by it.
- A clone is a response. It fits the defaults of 30 minutes and 5 GiB for all
  but the largest repositories and slowest links.
- A push is a request, and so is every other upload:
    - a git push;
    - an LFS object;
    - a container image layer;
    - a package file;
    - a release attachment.

    At the defaults, an upload larger than 100 MiB or taking more than 60
    seconds is cut off ("Size and time limits" in `SPEC.md`). A gitea that takes
    large uploads needs `SWWAF_REQUEST_MAX_BYTES`,
    `SWWAF_CLIENT_REQUEST_TIMEOUT` and `SWWAF_UPSTREAM_REQUEST_TIMEOUT` raised
    to fit.

- Archive download and blame or history pages are what scrapers hammer. The
  request limits do most of the work there.
- An Actions runner that reaches gitea through `smallwebwaf` sends requests all
  day. One older than version 0.4 (April 2026) asks for work every 2 seconds,
  43,200 requests a day, and reports a running job's log and state every second.
  So it passes the day limit of 50,000 after about an hour and a quarter of
  jobs. It is then banned, the job it is running fails, and each repeat within a
  day makes the ban longer. Newer runners ask less often, but a busy one, or
  several on one address, can still pass it. Put the runners' addresses in
  `SWWAF_RATE_LIMIT_EXEMPT_NETS`.

## What the Core Rule Set lets through

At the defaults, the Core Rule Set lets gitea's ordinary use through, apart from
the refusals in the next section:

- browsing and views of files in a repository, with their history, blame and the
  file tree;
- diffs, including their hidden lines and large files, and pull request review;
- git's clone, fetch and push over HTTP;
- signing in, including the return to the page a visitor came from, and sign-in
  with Git Credential Manager, git-credential-oauth or tea;
- the API's calls for a file and its commits;
- pushing and pulling container images and packages;
- Actions runners, and artifacts uploaded with `actions/upload-artifact@v4`;
- posting issues, pull requests, comments, wiki pages and files saved in the web
  editor, code included, since no body is read;
- the page gitea shows after a change, with its message naming what was done.

## What the Core Rule Set still refuses

Each refusal answers only that request ("Bans" in `SPEC.md` says what it counts
toward). The request log names the rule in `waf_rule_ids`, which
`SWWAF_WAF_DISABLED_RULES` can switch off.

### A query string that reads as an attack

Most often this is a search. A search term is a query parameter, which the Core
Rule Set checks against its lists of system files and commands (see the fourth
change under "Attack detection" in `SPEC.md`). A release attachment uploaded
through the API as `docker-compose.yml` is refused the same way. Examples:

- a name on those lists, such as `package.json`, `.gitignore` or
  `docker-compose.yml`;
- text that starts with a command name, such as `python3` or `ssh key`, or has
  one right after a `/` in its first word, such as `feat/docker-support`;
- a shell command with its options or a system path (`ls -la`, `sed -i`,
  `/bin/sh`), or a command in backticks;
- script code (`fetch(`, `${VAR}`, `process.env`), HTML (`<img src=`) or an SQL
  statement (`SELECT * FROM users WHERE`);
- a URL naming an IP address or `localhost`.

### A branch, tag or file name that starts with a command name

The Core Rule Set's list of commands (932260) holds names such as `docker-`,
`python3`, `ansible`, `base64` and `whoami`. A query parameter holding a branch,
tag or file name that starts with one is refused. So is one that has such a name
right after a `/`, such as `feat/docker-support`, `fix/docker-build` or
`renovate/docker-build-push-action-6.x`. gitea's own pages send the name in a
query parameter that 930120, 932160 and 932260 still check:

- `refSubUrl`, the branch or tag of a directory listing. A listing sends it when
  it asks for its entries' last commits in a second request. It does so whenever
  gitea takes more than a second to work them out;
- `name`, when a branch is deleted or restored on the branches page;
- `tag`, when a release is started from a tag;
- `template`, the file of an issue template, when an issue is opened from it;
- `rule_name`, when a branch protection rule is opened for editing in the
  repository's settings or has just been saved.

What a visitor sees, for a branch named `docker-build`:

- A directory listing that makes that second request leaves those last commits
  out and shows an error.
- The branches page shows an error instead of deleting or restoring the branch.
- A release started from such a tag gets the `403` answer of `smallwebwaf` in
  place of its form. So does an issue opened from such a template, and such a
  rule opened for editing.
- Saving such a rule stores it. gitea then returns to the branch settings page,
  which gets the `403` answer, so the save looks as if it failed.

### A file name in a query parameter that trips the code rules

The Core Rule Set's rules for Java, script, PowerShell and SQL find what they
look for in some file names. This holds too in the ten query parameters that
930120, 932160 and 932260 do not check (see the fourth change under "Attack
detection" in `SPEC.md`). Examples:

- `runtime` in OpenJDK's `src/java.base/share/classes/java/lang/Runtime.java`
  (944110);
- a Java class, as in `java.lang.String.md` (944130);
- `document.write.js` (941180);
- `process.env.d.ts` (934100);
- `__proto__` (934130);
- the PowerShell command `Install-Script`, as in `install-script.sh` (932120);
- a database's name, as in PostgreSQL's `information_schema.sql` (942140).

For such a file, these requests are refused:

- the API's list of its commits (`path`);
- the API's call for the contents of files that names it in its query (`body`);
- the commit graph of that file alone (`file`);
- the hidden lines of its diff (`path`), which stay hidden;
- the sign-in page, for a visitor who opens a page of the file that needs
  signing in, such as its edit page (`redirect_to`). The visitor can still sign
  in by opening the sign-in page itself.

### A path

- A file name ending in `~`, or an `.xhtml` file whose path holds a space.
- A path that holds what the Core Rule Set takes for a Java class (944130), as
  `java.lang.String.md` and
  `META-INF/services/org.apache.commons.logging.LogFactory` do.
- A path that holds what it takes for Node.js code (934100), as
  `process.env.d.ts` does.
- A path with a directory named `...` (930100, 930110), such as `.../notes.txt`.

For such a file, these are refused:

- the page of the file;
- its raw file;
- its history and its blame;
- its edit page.

The directory that holds it lists it, and a clone carries it.

### A container image push that reuses a layer

A push can reuse a layer of an image docker has pushed to that gitea before.
docker then asks gitea to take the layer from that image, naming it in the query
parameter `from`, which 932260 checks. The request is refused when the image's
owner starts with an entry on the list of commands. It is refused too when the
image's name after the owner starts with one. Examples are `owner/python3-app`,
`owner/docker-base`, and any image of an owner named `ansible` or `docker-team`.

What happens next depends on docker's image store. A docker that keeps its
images in containerd's image store fails the push, and fails each new try the
same way. A new install of Docker Engine 29 does this. A docker that keeps them
in its own older image store uploads the layer instead. The push then succeeds
after one refusal for each layer it reuses, and each of those refusals counts
toward the error burst ("Attack detection" in `SPEC.md`).

### Artifact uploads from `actions/upload-artifact@v3`

This action sends the header `Content-Range`, which the Core Rule Set refuses
(920450). The action sends two files at a time, does not retry a `403`, and
sends no further file once one is refused. So an upload is refused once or
twice, however many files it holds, and the step fails. One upload does not ban
the runner. The error burst ("Attack detection" in `SPEC.md`) bans it after more
than 30 such refusals from its address in a minute, as when many jobs upload at
once. `actions/upload-artifact@v4` does not send the header.

## What body inspection refuses

With `SWWAF_WAF_BODY_LIMIT` set, the Core Rule Set reads request bodies too. In
front of gitea it then refuses these, until their rule ids, named in the request
log, are added to `SWWAF_WAF_DISABLED_RULES`:

- issue and comment text, wiki pages and files saved in the web editor that hold
  shell commands or code (932125, 932235, 932250 and others);
- package descriptions that show code;
- PyPI uploads (922130);
- attachments named like `debug.log` or `config.yml` (932180).

## What `script/gitea-requests` sends

Of the requests above, the script sends:

- for each file named under "A file name in a query parameter that trips the
  code rules", the API's list of its commits;
- for `Runtime.java` alone, the commit graph of that file, the hidden lines of
  its diff, and the API's call for the contents of files that names it;
- the sign-in page for a visitor who opens the edit page of `document.write.js`;
- the pages of `java.lang.String.md`,
  `META-INF/services/org.apache.commons.logging.LogFactory`, `process.env.d.ts`
  and `.../notes.txt`;
- one container image push that reuses a layer, which it does not try again.

It does not send the raw file, history, blame or edit page of those four files,
or the pages of the directories `META-INF/services` and `...`. It also sends a
short sample of gitea's ordinary use:

- signing in;
- pages of files and commits, and a diff;
- the API;
- a push, and clone and fetch over HTTP;
- two container image pushes.