Filter out rooms from the room directory being served to other homeservers when those rooms block that homeserver by their Access Control Lists. (#16759)

The idea here being that the directory server shouldn't advertise rooms
to a requesting server is the requesting server would not be allowed to
join or participate in the room.

<!--
Fixes: # <!-- -->
<!--
Supersedes: # <!-- -->
<!--
Follows: # <!-- -->
<!--
Part of: # <!-- -->
Base: `develop` <!-- git-stack-base-branch:develop -->

<!--
This pull request is commit-by-commit review friendly. <!-- -->
<!--
This pull request is intended for commit-by-commit review. <!-- -->

Original commit schedule, with full messages:

<ol>
<li>

Pass `from_federation_origin` down into room list retrieval code 

</li>
<li>

Don't cache /publicRooms response for inbound federated requests 

</li>
<li>

fixup! Don't cache /publicRooms response for inbound federated requests 

</li>
<li>

Cap the number of /publicRooms entries to 100 

</li>
<li>

Simplify code now that you can't request unlimited rooms 

</li>
<li>

Filter out rooms from federated requests that don't have the correct ACL

</li>
<li>

Request a handful more when filtering ACLs so that we can try to avoid
shortchanging the requester

</li>
</ol>

---------

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/synapse/federation/transport/server/__init__.py b/synapse/federation/transport/server/__init__.py
index 839092e4d3..74391e3cb2 100644
--- a/synapse/federation/transport/server/__init__.py
+++ b/synapse/federation/transport/server/__init__.py
@@ -154,7 +154,10 @@ class PublicRoomList(BaseFederationServlet):
             limit = None
 
         data = await self.handler.get_local_public_room_list(
-            limit, since_token, network_tuple=network_tuple, from_federation=True
+            limit,
+            since_token,
+            network_tuple=network_tuple,
+            from_federation_origin=origin,
         )
         return 200, data
 
@@ -195,7 +198,7 @@ class PublicRoomList(BaseFederationServlet):
             since_token=since_token,
             search_filter=search_filter,
             network_tuple=network_tuple,
-            from_federation=True,
+            from_federation_origin=origin,
         )
 
         return 200, data