Faster Remote Room Joins: tell remote homeservers that we are unable to authorise them if they query a room which has partial state on our server. (#13823)

1 files changed, 3 insertions, 8 deletions

diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 3bf84cf625..907940e19e 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -530,13 +530,10 @@ class FederationServer(FederationBase):
     async def on_room_state_request(
         self, origin: str, room_id: str, event_id: str
     ) -> Tuple[int, JsonDict]:
+        await self._event_auth_handler.assert_host_in_room(room_id, origin)
         origin_host, _ = parse_server_name(origin)
         await self.check_server_matches_acl(origin_host, room_id)
 
-        in_room = await self._event_auth_handler.check_host_in_room(room_id, origin)
-        if not in_room:
-            raise AuthError(403, "Host not in room.")
-
         # we grab the linearizer to protect ourselves from servers which hammer
         # us. In theory we might already have the response to this query
         # in the cache so we could return it without waiting for the linearizer
@@ -560,13 +557,10 @@ class FederationServer(FederationBase):
         if not event_id:
             raise NotImplementedError("Specify an event")
 
+        await self._event_auth_handler.assert_host_in_room(room_id, origin)
         origin_host, _ = parse_server_name(origin)
         await self.check_server_matches_acl(origin_host, room_id)
 
-        in_room = await self._event_auth_handler.check_host_in_room(room_id, origin)
-        if not in_room:
-            raise AuthError(403, "Host not in room.")
-
         resp = await self._state_ids_resp_cache.wrap(
             (room_id, event_id),
             self._on_state_ids_request_compute,
@@ -955,6 +949,7 @@ class FederationServer(FederationBase):
         self, origin: str, room_id: str, event_id: str
     ) -> Tuple[int, Dict[str, Any]]:
         async with self._server_linearizer.queue((origin, room_id)):
+            await self._event_auth_handler.assert_host_in_room(room_id, origin)
             origin_host, _ = parse_server_name(origin)
             await self.check_server_matches_acl(origin_host, room_id)