Fixes #18150 

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---------

Co-authored-by: Erik Johnston <erikj@element.io>

MSC4108 relies on ETag to determine if something has changed on the
rendez-vous channel.
Strong and correct ETag comparison works if the response body is
bit-for-bit identical, which isn't the case if a proxy in the middle
compresses the response on the fly.

This adds a `no-transform` directive to the `Cache-Control` header,
which tells proxies not to transform the response body.

Additionally, some proxies (nginx) will switch to `Transfer-Encoding:
chunked` if it doesn't know the Content-Length of the response, and
'weakening' the ETag if that's the case. I've added `Content-Length`
headers to all responses, to hopefully solve that.

This basically fixes QR-code login when nginx or cloudflare is involved,
with gzip/zstd/deflate compression enabled.

Bumps [types-psycopg2](https://github.com/python/typeshed) from
2.9.21.20241019 to 2.9.21.20250121.
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Bumps
[sigstore/cosign-installer](https://github.com/sigstore/cosign-installer)
from 3.8.0 to 3.8.1.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/sigstore/cosign-installer/releases">sigstore/cosign-installer's
releases</a>.</em></p>
<blockquote>
<h2>v3.8.1</h2>
<h2>What's Changed</h2>
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<li>use cosign 2.4.3 and other updates by <a
href="https://github.com/cpanato"><code>@​cpanato</code></a> in <a
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This is in line with our general policy of ensuring that the default
config is reasonably locked down.

SyTest PR to fix tests: https://github.com/matrix-org/sytest/pull/1396

Missed in the first round.

Add support for overriding `id_token_signing_alg_values_supported` for an OpenID identity provider (#18177)

Normally, when `discovery` is enabled,
`id_token_signing_alg_values_supported` comes from the OpenID Discovery
Document (`/.well-known/openid-configuration`). If nothing was
specified, we default to supporting `RS256` in the downstream usage.

This PR just adds support for adding a default/overriding the the
discovered value [just like we do for other things like the
`token_endpoint`](https://github.com/element-hq/synapse/blob/1525a3b4d48a0f5657d61423e1f205bff9a77948/docs/usage/configuration/config_documentation.md#oidc_providers),
etc.

Missed in the transition from experimental to stable. 

Fixes #18160

This is a split off #18033 

This uses a few tricks to speed up the building of docker images:

- This switches to use `uv pip install` instead of `pip install`. This
saves a bunch of time, especially when cross-compiling
- I then looked at what packages were not using binary wheels: I
upgraded MarkupSafe to have binaries for py3.12, and got back to Python
3.12 because hiredis didn't have builds for py3.13 with the version we
were using
- The generation of the requirements.txt is arch-agnostic, so I've
switched this one to run on the build architecture, so that both arch
can share it
- The download of runtime depdendencies can be done on the build
architecture through manual `apt-get download` plus `dpkg --extract`
- We were using -slim images, but still installed a bunch of -dev
dependencies. Turns out, all the dev dependencies were already installed
in the non-slim image, which saves a bunch of time as well

This has been a problem with Element Web, as it will proble /register
with an empty body, which gave this error:

```
curl -d '{}' -HContent-Type:application/json /_matrix/client/v3/register

{"errcode": "M_UNKNOWN",
 "error": "Invalid username"}
```

And Element Web would choke on it. This changes that so we reply
instead:

```
{"errcode": "M_FORBIDDEN",
 "error": "Registration has been disabled. Only m.login.application_service registrations are allowed."}
```

Also adds a test for this.

See https://github.com/element-hq/element-web/issues/27993



---------

Co-authored-by: Andrew Morgan <andrew@amorgan.xyz>

### Pull Request Checklist

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- Add `get_current_time_msec()` method to the [module
API](https://matrix-org.github.io/synapse/latest/modules/writing_a_module.html

)
for sound time comparisons with Synapse.
- Fixes #18104 

Signed-off-by: Ahmed Qashlan <ahmedelqashlan@gmail.com>
Co-authored-by: Eric Eastwood <madlittlemods@gmail.com>
Co-authored-by: Erik Johnston <erikj@jki.re>

Adds new environment variables that can be used with the Docker image
(`SYNAPSE_HTTP_PROXY`/`SYNAPSE_HTTPS_PROXY`/`SYNAPSE_NO_PROXY`)

Useful for things like the [Secure Border
Gateway](https://element.io/server-suite/secure-border-gateways)


### Why is this necessary?

You can already configure the `HTTP_PROXY`/`HTTPS_PROXY` environment
variables to proxy outbound requests but setting this globally in the
Docker image affects all processes which isn't always desirable or
workable in the case where the proxy is running in the Docker image
itself (because the Debian packages will fail to download because the
proxy isn't up and running yet) . Adding Synapse specific environment
variables
(`SYNAPSE_HTTP_PROXY`/`SYNAPSE_HTTPS_PROXY`/`SYNAPSE_NO_PROXY`) makes
things much more targetable.

If a user search has many words we can end up creating really large
queries that take a long time for the database to process. Generally,
such searches don't return any results anyway (due to limits on user ID
and display name length).

We "fix" this by cheating and only searching for the first ten words.

Document consequences of replacing secrets. The covered config options
are `registration_shared_secret`, `macaroon_secret_key`, `form_secret`
and `worker_replication_secret`.

Even though I looked at the source code to check the added documentation
is right, I would appreciate additional verification of the statements
made.

In an hand-wavy attempt at classifying how bad the consequences of
secret replacement are, I added some explanations as warnings and others
as regular paragraphs.

Closes #17971 

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I was looking into the `USE_FROZEN_DICTS` option during the review of
https://github.com/element-hq/synapse/pull/18103#discussion_r1935876168
and noticed that there are several other server config options that
aren't in the docs.

This is to help track down a possible, but very rare, worker deadlock
that was seen on matrix.org.
In theory, you could work back from an instance of these new logs to the
approximate time when the lock was obtained and focus the diagnostic
efforts there.

### Pull Request Checklist

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When updating 3pid for a user email from admin api and sending invalid
email the server throws 500 internal server error.
changed to 400 Bad request and returned the error message

Signed-off-by: qashlan <ahmedelqashlan@gmail.com>
Signed-off-by: Ahmed Qashlan <ahmedelqashlan@gmail.com>

Missed in https://github.com/element-hq/synapse/pull/18000

Some small cleanups after Python3.8 became EOL.

- Move some type imports from `typing_extensions` to `typing`
- Remove the `abi3-py38` feature from pyo3

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---------

Co-authored-by: Quentin Gliech <quenting@element.io>

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---------

Co-authored-by: Quentin Gliech <quenting@element.io>

In the current `attribute_requirements` implementation it is only
possible to allow exact matching attribute values. Multiple allowed
values for one attribute are not possible as described in #13238.

### Pull Request Checklist

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---------

Co-authored-by: Sebastian Neuser <pzkz@infra.run>
Co-authored-by: Quentin Gliech <quenting@element.io>

We log incorrect ones as we want to catch bugs where Synapse returns bad
tokens. However, sometimes clients just send tokens that are e.g. empty.

---------

Co-authored-by: Eric Eastwood <erice@element.io>

### Pull Request Checklist

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"Fixed a bug that prevented receiving messages from other servers."
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  - End with either a period (.) or an exclamation mark (!).
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I forgot the guide applies to Oracle Linux as well. In fact, I ran a
small homeserver on OEL a few months back.

I did minimal installations on Rocky and OEL on VirtualBox and noticed
Codeready/Powertools repos aren't required, so I removed those commands
from the guide. I switched `RHEL`-references to `EL`.

#17423 was merged before I remembered about OEL but a new PR shouldn't
hurt :)

---------

Co-authored-by: Quentin Gliech <quenting@element.io>