any user can currently query any other user's displayname and avatar over federation if they know their userid. (SPEC-374)

[matrixbot]

Submitted by @​matthew:matrix.org
this seems needlessly leaky

(Imported from https://matrix.org/jira/browse/SPEC-374)

[CySlider]

I would like to add, that the spec should allow to specify a different avatar for each room you are in.
Also in RL you would not show up with a tuxedo at your local hangout or in shorts on a business meeting.

If done right, this would allow to not set any default avatar, but a cute (maybe publicly embarrassing) one in the encrypted family chat that is not public (best avatar is also encrypted) hence not giving away anything unnecessary to the public as the OP mentioned.

[non-Jedi]

@CySlider spec currently allows per-room displaynames and avatars. It's just not a functionality exposed in Riot. (Avatars and displaynames are really just per-room state events that Riot pretends are user attributes rather than room attributes)

[CySlider]

@non-Jedi Perfect. Kinda missed that in my quick scan. Sorry for my ignorance. If I find some free time I'll see if I can create a pull request for Riot making use of this.

[CySlider]

Hmm, I checked the spec again and I can not see any API call to set a room specific avatar.
Yes, a room event can carry an avatar, but it's purpose seems to be to have a history of avatars to be able to always display the avatar that the user has had, when he did send a message.

The only way for the client to set an avatar seems to be:

 "8.3   PUT /_matrix/client/r0/profile/{userId}/avatar_url"

which clearly is not room aware.

Even if I send an room event with the intent to override the user's avatar with an m.room.member event.
the spec says "avatar_url string The avatar URL for this user, if any. This is added by the homeserver." Which suggests that this field is not supposed to be set by the client, but rather by the server with the current profile avatar.

I would suggest a call like:

  PUT /_matrix/client/r0/rooms/{roomId}/members/{userId}/avatar_url

Which overrides the default avatar for the user in that room.

UPDATE: PUT not GET

[leonerd]

You can set a per-room avatar or displayname by just setting the values into your own m.room.member event.

[ara4n]

matrix-org/synapse#5083 covers this for the CS API, but not SS API

[Bubu]

Today I learned about one org that is running their synapse without federation because of privacy concerns regarding this issue.

[Bubu]

This seems to be fixed in synapse by matrix-org/synapse#9203?