Synapse: 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.