/_synapse/admin/v1/users/<uid>/admin Fails if user id is URL encoded

[NHAS]

Description

GET /_synapse/admin/v1/users/<user_id>/admin doesnt allow for URL encoded user_ids, as such this disable some UI functionality in riot.im, which is where I first noticed it. As it was giving a 400 error.

Steps to reproduce

1. Get valid admin token
2. GET /_synapse/admin/v1/users/%40admin%3amatrix.server/admin
3. View response as error

What should happen is url encoding is causing the regex not to match. Caused by a regex on line:

synapse/synapse/rest/admin/users.py

Line 430 in c2ba994

PATTERNS = (re.compile("^/_synapse/admin/v1/users/(?P<user_id>@[^/]*)/admin$"),)

That should be:
PATTERNS = (re.compile("^/_synapse/admin/v1/users/(?P<user_id>[^/]*)/admin$"),)

Which removes the "@" symbol requirement.

Version information

• Homeserver: personal private homeserver, not matrix.org

If not matrix.org:

• Version: {"server_version": "1.8.0", "python_version": "3.6.9"}

• Install method: Apt package manager, after importing keys as per install instruction

• Platform: Ubuntu 18.04, running within a VM, Nginx reverse proxy

Although this is behind the NGINX reverse proxy, I have also tested this via localhost:8008 and it still presents the problem.

[anoadragon453]

Fixed in, #6825. Thanks!