Recover room admin where it has been lost

[bobobo1618]

So I got in an incredibly annoying situation:

• I'm admin or moderator of a room (I forget)
• I add a moderator to a room
• The moderator kicks and bans me by accident, then unbans me and reinvites me
• Now nobody in the room has the permissions necessary to add/remove moderators

How can I resolve this?

[bobobo1618]

I eventually figured out an (extremely hacky) workaround:

• Open synapse/event_auth.py
• Add return True on the line after def _can_send_event
• Add return True on the line after def _check_power_levels
• Restart
• Change permissions
• Remove code changes
• Restart

Clearly this is not the best choice. I think in production return True should be replaced with if is_server_admin: return True.

[dreamflasher]

How does one set the power level in the postgres database?

[Half-Shot]

This issue should probably be closed. The advice above should not be followed as it messes with event authorization which will not work over federation.

[richvdh]

https://github.com/matrix-org/matrix-doc/issues/652

[richvdh]

I'm admin or moderator of a room (I forget)
I add a moderator to a room
The moderator kicks and bans me by accident, then unbans me and reinvites me
Now nobody in the room has the permissions necessary to add/remove moderators

This doesn't sound right, incidentally. You should end up with the same power-level after ban/rejoin as you had before it.

[tanius]

How does one set the power level in the postgres database?

I tried to figure that out today, but it did not work. Tried about five different routes, but things don't behave as in the API documentation. Namely, even when I there are no m.room.power-levels messages left for the room and I am entered as the creator as the room in table rooms and have restarted the Matrix server and reloaded the , I am still not admin in that room. There's probably something going on with caching that I don't see. But it's not client-side local storage, because it also happens in Firefox Private Mode.

So doing things in the database is not a solution (for now). On top of that, the Matrix Admin API does not contain a function to modify room membership or permissions. So being a "server admin" user does not help here, either.

I propose to re-open this issue and implement changing power levels and room membership in the admin API.

[rettichschnidi]

This prblem seems to have a nice solution by now: https://github.com/matrix-org/synapse/blob/develop/docs/admin_api/rooms.md#make-room-admin-api

[Exagone313]

Is it possible to reopen this issue? I'm trying to use the make room admin api linked above, but I get a Bad Request error:

{"errcode":"M_UNKNOWN","error":"No local admin user in room"}

My user was set to admin (in users table) and I use the access token given in Element client.

Context is, the admin that created the room left the the room and there is no longer any admin in the room. The admin actually left the company, so they could not rejoin the room (if that worked).

[richvdh]

This issue is closed because it is a known problem in the Matrix protocol, rather than Synapse, which is tracked at matrix-org/matrix-spec#165.

[Exagone313]

The specification issue seems a bit different than the general problem titled by this issue. Maybe I could open a different issue, though, since my issue is different than OP's. It could also be an issue to be filled in specs.

[richvdh]

@Exagone313: it sounds like you're misunderstanding what the "make room admin" API does. As the documentation says, it will give the calling user "the highest power available to a local user who is in the room". If there is no admin in the room, then clearly that doesn't help you.

If you administer the server for the departed user, then you might be able to use the room_membership admin API to rejoin them to the room, or the login as user API to get an access token, and then call the "join" API on their behalf. And then use the make-room-admin API.