Change displayname of users as admin does not work

[dklimpel]

Description

I try to change the displayname of other users as admin. The change in profile ist ok, but I get errors for displayname in rooms.

2019-12-19 14:45:57,831 - synapse.access.http.8008 - 233 - INFO - PUT-906- - - 8008 - Received request: PUT /_matrix/client/r0/profile/@user:server.cloudapp.azure.com/displayname
2019-12-19 14:45:57,932 - synapse.handlers.message - 695 - WARNING - PUT-906- Denying new event <FrozenEventV3 event_id='$e_mVDdJ-rQVW25vaOgXIU3zNppPZfOCJUo5YhMQ0rTM', type='m.room.member', state_key='@user:server.cloudapp.azure.com'> because 403: Cannot force another user to join.
2019-12-19 14:45:57,932 - synapse.handlers.profile - 281 - WARNING - PUT-906- Failed to update join event for room !GstgHdhajwAvSueHan:server.cloudapp.azure.com - 403: Cannot force another user to join.
2019-12-19 14:45:57,966 - synapse.handlers.message - 695 - WARNING - PUT-906- Denying new event <FrozenEvent event_id='$157676675735pBzAC:server.cloudapp.azure.com', type='m.room.member', state_key='@user:server.cloudapp.azure.com'> because 403: Cannot force another user to join.
2019-12-19 14:45:57,967 - synapse.handlers.profile - 281 - WARNING - PUT-906- Failed to update join event for room !AvSWOczTtSmEVpjVlF:server.cloudapp.azure.com - 403: Cannot force another user to join.
2019-12-19 14:45:58,724 - synapse.access.http.8008 - 302 - INFO - PUT-906- - - 8008 - {@admin_user:server.cloudapp.azure.com} Processed request: 0.892sec/0.000sec (0.051sec, 0.011sec) (0.085sec/0.662sec/109) 3B 200 "PUT /_matrix/client/r0/profile/@user:server.cloudapp.azure.com/displayname HTTP/1.1" "curl/7.58.0" [0 dbevts]

Steps to reproduce

curl -X PUT --header 'Authorization: Bearer access_token' --header 'Content-Type: application/json' --header 'Accept: application/json' -d '{ "displayname": "new name" }' 'http://localhost:8008/_matrix/client/r0/profile/@user:server.cloudapp.azure.com/displayname' -i

HTTP/1.1 200 OK
Server: Synapse/1.6.1
Date: Thu, 19 Dec 2019 14:45:57 GMT
Content-Type: application/json
Content-Length: 3
Cache-Control: no-cache, no-store, must-revalidate
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept, Authorization

{}

Version information

• Homeserver:

If not matrix.org:

• Version: v1.6.1

• Install method: Ubuntu/Debian package manager

• Platform: Ubuntu, Azure VM

How can I support? Do you need more informations?
Callled function: https://github.com/matrix-org/synapse/blob/master/synapse/handlers/profile.py#L257
Error: https://github.com/matrix-org/synapse/blob/master/synapse/event_auth.py#L294

[richvdh]

the basic problem is that other servers in the room have no way to know that your user is an admin, so they wouldn't know that you are allowed to send membership events on behalf of the other user.

A potential fix to this would be for synapse to spoof a membership event from the target_user.

[dklimpel]

similar to: #5763 (comment)

[awesome-manuel]

You can use the new admin API: https://github.com/matrix-org/synapse/blob/master/docs/admin_api/user_admin_api.rst

[dklimpel]

Yes, you can use the API to change the displayname. But it changes not the displayname of user in all rooms. It's changing only with a a new join event. Displayname of an user in a room and displayname of an user are not the same an are stored in different tabels.

[richvdh]

fiext by #6876 I think