Option to allow server admins to join complex rooms (#7902)

Fixes #7901.

Signed-off-by: Niklas Tittjung <nik_t.01@web.de>

2 files changed, 13 insertions, 2 deletions

diff --git a/synapse/config/server.py b/synapse/config/server.py
index 3747a01ca7..848587d232 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -439,6 +439,9 @@ class ServerConfig(Config):
                 validator=attr.validators.instance_of(str),
                 default=ROOM_COMPLEXITY_TOO_GREAT,
             )
+            admins_can_join = attr.ib(
+                validator=attr.validators.instance_of(bool), default=False
+            )
 
         self.limit_remote_rooms = LimitRemoteRoomsConfig(
             **(config.get("limit_remote_rooms") or {})
@@ -893,6 +896,10 @@ class ServerConfig(Config):
           #
           #complexity_error: "This room is too complex."
 
+          # allow server admins to join complex rooms. Default is false.
+          #
+          #admins_can_join: true
+
         # Whether to require a user to be in the room to add an alias to it.
         # Defaults to 'true'.
         #
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index a1a8fa1d3b..5a40e8c144 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -952,7 +952,11 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         if len(remote_room_hosts) == 0:
             raise SynapseError(404, "No known servers")
 
-        if self.hs.config.limit_remote_rooms.enabled:
+        check_complexity = self.hs.config.limit_remote_rooms.enabled
+        if check_complexity and self.hs.config.limit_remote_rooms.admins_can_join:
+            check_complexity = not await self.hs.auth.is_server_admin(user)
+
+        if check_complexity:
             # Fetch the room complexity
             too_complex = await self._is_remote_room_too_complex(
                 room_id, remote_room_hosts
@@ -975,7 +979,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
 
         # Check the room we just joined wasn't too large, if we didn't fetch the
         # complexity of it before.
-        if self.hs.config.limit_remote_rooms.enabled:
+        if check_complexity:
             if too_complex is False:
                 # We checked, and we're under the limit.
                 return event_id, stream_id