Related to https://github.com/element-hq/synapse/issues/17035, when
Synapse receives a request that is larger than the maximum size allowed,
it aborts the connection without ever sending back a HTTP response.
I dug into our usage of twisted and how best to try and report such an
error and this is what I came up with.
It would be ideal to be able to report the status from within
`handleContentChunk` but that is called too early on in the twisted http
handling code, before things have been setup enough to be able to
properly write a response.
I tested this change out locally (both with C-S and S-S apis) and they
do receive a 413 response now in addition to the connection being
closed.
Hopefully this will aid in being able to quickly detect when
https://github.com/element-hq/synapse/issues/17035 is occurring as the
current situation makes it very hard to narrow things down to that
specific issue without making a lot of assumptions.
This PR also responds with more meaningful error codes now in the case
of:
- multiple `Content-Length` headers
- invalid `Content-Length` header value
- request content size being larger than the `Content-Length` value
### Pull Request Checklist
<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->
* [X] Pull request is based on the develop branch
* [X] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
- Use markdown where necessary, mostly for `code blocks`.
- End with either a period (.) or an exclamation mark (!).
- Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [X] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct (run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))
---------
Co-authored-by: Eric Eastwood <erice@element.io>
Introduce `Clock.call_when_running(...)` to wrap startup code in a
logcontext, ensuring we can identify which server generated the logs.
Background:
> Ideally, nothing from the Synapse homeserver would be logged against the `sentinel`
> logcontext as we want to know which server the logs came from. In practice, this is not
> always the case yet especially outside of request handling.
>
> Global things outside of Synapse (e.g. Twisted reactor code) should run in the
> `sentinel` logcontext. It's only when it calls into application code that a logcontext
> gets activated. This means the reactor should be started in the `sentinel` logcontext,
> and any time an awaitable yields control back to the reactor, it should reset the
> logcontext to be the `sentinel` logcontext. This is important to avoid leaking the
> current logcontext to the reactor (which would then get picked up and associated with
> the next thing the reactor does).
>
> *-- `docs/log_contexts.md`
Also adds a lint to prefer `Clock.call_when_running(...)` over
`reactor.callWhenRunning(...)`
Part of https://github.com/element-hq/synapse/issues/18905
You can now configure how much media can be uploaded by a user in a
given time period.
Note the first commit here is a refactor of create/upload content
function
This PR makes a few radical changes to media. This now stores the SHA256
hash of each file stored in the database (excluding thumbnails, more on
that later). If a set of media is quarantined, any additional uploads of
the same file contents or any other files with the same hash will be
quarantined at the same time.
Currently this does NOT:
- De-duplicate media, although a future extension could be to do that.
- Run any background jobs to identify the hashes of older files. This
could also be a future extension, though the value of doing so is
limited to combat the abuse of recent media.
- Hash thumbnails. It's assumed that thumbnails are parented to some
form of media, so you'd likely be wanting to quarantine the media and
the thumbnail at the same time.
We do a few things in this PR to better support caching:
1. Change `Cache-Control` header to allow intermediary proxies to cache
media *only* if they revalidate on every request. This means that the
intermediary cache will still send the request to Synapse but with a
`If-None-Match` header, at which point Synapse can check auth and
respond with a 304 and empty content.
2. Add `ETag` response header to all media responses. We hardcode this
to `1` since all media is immutable (beyond being deleted).
3. Check for `If-None-Match` header (after checking for auth), and if it
matches then respond with a 304 and empty body.
---------
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
I thought ruff check would also format, but it doesn't.
This runs ruff format in CI and dev scripts. The first commit is just a
run of `ruff format .` in the root directory.
Prior to this PR, remote downloads which did not provide a
`content-length` were decremented from the remote download ratelimiter
at the max allowable size, leading to excessive ratelimiting - see
https://github.com/element-hq/synapse/issues/17394.
This PR adds a linearizer to limit concurrent remote downloads to 6 per
IP address, and decrements remote downloads without a `content-length`
from the ratelimiter *after* the download is complete and the response
length is known.
Also adds logic to ensure that responses with a known length respect the
`max_download_size`.
When a module rejects a piece of media we end up trying to close the
same logging context twice.
Instead of fixing the existing code we refactor to use an async context
manager, which is easier to write correctly.
