* Remove references to handler._auth_handler

(and replace them with hs.get_auth_handler)

* Factor out a utility function for building Requests

* Remove mocks of `OidcHandler._map_userinfo_to_user`

This method is going away, so mocking it out is no longer a valid approach.

Instead, we mock out lower-level methods (eg _remote_id_from_userinfo), or
simply allow the regular implementation to proceed and update the expectations
accordingly.

* Remove references to `OidcHandler._map_userinfo_to_user` from tests

This method is going away, so we can no longer use it as a test point. Instead
we build mock "callback" requests which we pass into `handle_oidc_callback`,
and verify correct behaviour by mocking out `AuthHandler.complete_sso_login`.

Spam checker modules can now provide async methods. This is implemented
in a backwards-compatible manner.

Fixes #8846.

Fixes #8866

Fixes #8892

* Factor out _call_attribute_mapper and _register_mapped_user

This is mostly an attempt to simplify `get_mxid_from_sso`.

* Move mapping_lock down into SsoHandler.

this was using `canonical_json` without setting it, so when you used it as a
standalone class, you would get exceptions.

Deprecate both APIs in favour of the Delete Room API.

Related: #8663 and #8810

This defaults `ip_range_blacklist` to reserved IP ranges and also adds an
`ip_range_whitelist` setting to override it.

Related: #8810
Also a few small improvements.

Signed-off-by: Dirk Klimpel <dirk@klimpel.org>

Pin the docker version for multiarch builds

It seems that letting CircleCI use its default docker version (17.09.0-ce,
apparently) did not interact well with multiarch builds: in particular, we saw
weird effects where running an amd64 build at the same time as an arm64 build
caused the arm64 builds to fail with:

   Error while loading /usr/sbin/dpkg-deb: No such file or directory

Synapse 1.23.1 (2020-12-09)
===========================

Due to the two security issues highlighted below, server administrators are
encouraged to update Synapse. We are not aware of these vulnerabilities being
exploited in the wild.

Security advisory
-----------------

The following issues are fixed in v1.23.1 and v1.24.0.

- There is a denial of service attack
  ([CVE-2020-26257](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26257))
  against the federation APIs in which future events will not be correctly sent
  to other servers over federation. This affects all servers that participate in
  open federation. (Fixed in [#8776](https://github.com/matrix-org/synapse/pull/8776)).

- Synapse may be affected by OpenSSL
  [CVE-2020-1971](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1971).
  Synapse administrators should ensure that they have the latest versions of
  the cryptography Python package installed.

To upgrade Synapse along with the cryptography package:

* Administrators using the [`matrix.org` Docker
  image](https://hub.docker.com/r/matrixdotorg/synapse/) or the [Debian/Ubuntu
  packages from
  `matrix.org`](https://github.com/matrix-org/synapse/blob/master/INSTALL.md#matrixorg-packages)
  should ensure that they have version 1.24.0 or 1.23.1 installed: these images include
  the updated packages.
* Administrators who have [installed Synapse from
  source](https://github.com/matrix-org/synapse/blob/master/INSTALL.md#installing-from-source)
  should upgrade the cryptography package within their virtualenv by running:
  ```sh
  <path_to_virtualenv>/bin/pip install 'cryptography>=3.3'
  ```
* Administrators who have installed Synapse from distribution packages should
  consult the information from their distributions.

Bugfixes
--------

- Fix a bug in some federation APIs which could lead to unexpected behaviour if different parameters were set in the URI and the request body. ([\#8776](https://github.com/matrix-org/synapse/issues/8776))

Internal Changes
----------------

- Add a maximum version for pysaml2 on Python 3.5. ([\#8898](https://github.com/matrix-org/synapse/issues/8898))

This pins pysaml2 to < 6.4.0 on Python 3.5, as the last known working version.

* Consistently use room_id from federation request body

Some federation APIs have a redundant `room_id` path param (see
https://github.com/matrix-org/matrix-doc/issues/2330). We should make sure we
consistently use either the path param or the body param, and the body param is
easier.

* Kill off some references to "context"

Once upon a time, "rooms" were known as "contexts". I think this kills of the
last references to "contexts".

Fixes / related to: https://github.com/matrix-org/synapse/issues/6533

This should do essentially the same thing as a robots.txt file telling robots to not index the media repo. https://developers.google.com/search/reference/robots_meta_tag



Signed-off-by: Aaron Raimist <aaron@raim.ist>

This pins pysaml2 to < 6.4.0 on Python 3.5, as the last known working version.

The idea is that the parse_config method of extension modules can raise either a ConfigError or a JsonValidationError,
and it will be magically turned into a legible error message. There's a few components to it:

* Separating the "path" and the "message" parts of a ConfigError, so that we can fiddle with the path bit to turn it
   into an absolute path.
* Generally improving the way ConfigErrors get printed.
* Passing in the config path to load_module so that it can wrap any exceptions that get caught appropriately.

* SsoHandler: remove inheritance from BaseHandler

* Simplify the flow for SSO UIA

We don't need to do all the magic for mapping users when we are doing UIA, so
let's factor that out.

* Call set_avatar_url with target_user, not user_id

Fixes https://github.com/matrix-org/synapse/issues/8871



* Create 8872.bugfix

* Update synapse/rest/admin/users.py

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

* Testing

* Update changelog.d/8872.bugfix

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

Authentication is done by checking a shared secret provided
in the Synapse configuration file.

This is so that we can choose which algorithm to use based on the room ID.

Pusher URLs now must end in `/_matrix/push/v1/notify` per the
specification.