diff options
| -rw-r--r-- | synapse/federation/federation_server.py | 8 | ||||
| -rw-r--r-- | synapse/handlers/federation.py | 16 |
2 files changed, 19 insertions, 5 deletions
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py index 510a176821..bc20b9c201 100644 --- a/synapse/federation/federation_server.py +++ b/synapse/federation/federation_server.py @@ -146,11 +146,15 @@ class FederationServer(FederationBase): # check that it's actually being sent from a valid destination to # workaround bug #1753 in 0.18.5 and 0.18.6 if transaction.origin != get_domain_from_id(pdu.event_id): + # We continue to accept join events from any server; this is + # necessary for the federation join dance to work correctly. + # (When we join over federation, the "helper" server is + # responsible for sending out the join event, rather than the + # origin. See bug #1893). if not ( pdu.type == 'm.room.member' and pdu.content and - pdu.content.get("membership", None) == 'join' and - self.hs.is_mine_id(pdu.state_key) + pdu.content.get("membership", None) == 'join' ): logger.info( "Discarding PDU %s from invalid origin %s", diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index 888dd01240..2ecc0087b8 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -1004,9 +1004,19 @@ class FederationHandler(BaseHandler): ) event.internal_metadata.outlier = False - # Send this event on behalf of the origin server since they may not - # have an up to data view of the state of the room at this event so - # will not know which servers to send the event to. + # Send this event on behalf of the origin server. + # + # The reasons we have the destination server rather than the origin + # server send it are slightly mysterious: the origin server should have + # all the neccessary state once it gets the response to the send_join, + # so it could send the event itself if it wanted to. It may be that + # doing it this way reduces failure modes, or avoids certain attacks + # where a new server selectively tells a subset of the federation that + # it has joined. + # + # The fact is that, as of the current writing, Synapse doesn't send out + # the join event over federation after joining, and changing it now + # would introduce the danger of backwards-compatibility problems. event.internal_metadata.send_on_behalf_of = origin context, event_stream_id, max_stream_id = yield self._handle_new_event( |