diff --git a/synapse/visibility.py b/synapse/visibility.py
index 40a9c5b53f..b443857571 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -563,7 +563,8 @@ def get_effective_room_visibility_from_state(state: StateMap[EventBase]) -> str:
async def filter_events_for_server(
storage: StorageControllers,
- server_name: str,
+ target_server_name: str,
+ local_server_name: str,
events: List[EventBase],
redact: bool = True,
check_history_visibility_only: bool = False,
@@ -603,7 +604,7 @@ async def filter_events_for_server(
# if the server is either in the room or has been invited
# into the room.
for ev in memberships.values():
- assert get_domain_from_id(ev.state_key) == server_name
+ assert get_domain_from_id(ev.state_key) == target_server_name
memtype = ev.membership
if memtype == Membership.JOIN:
@@ -622,6 +623,24 @@ async def filter_events_for_server(
# to no users having been erased.
erased_senders = {}
+ # Filter out non-local events when we are in the middle of a partial join, since our servers
+ # list can be out of date and we could leak events to servers not in the room anymore.
+ # This can also be true for local events but we consider it to be an acceptable risk.
+
+ # We do this check as a first step and before retrieving membership events because
+ # otherwise a room could be fully joined after we retrieve those, which would then bypass
+ # this check but would base the filtering on an outdated view of the membership events.
+
+ partial_state_invisible_events = set()
+ if not check_history_visibility_only:
+ for e in events:
+ sender_domain = get_domain_from_id(e.sender)
+ if (
+ sender_domain != local_server_name
+ and await storage.main.is_partial_state_room(e.room_id)
+ ):
+ partial_state_invisible_events.add(e)
+
# Let's check to see if all the events have a history visibility
# of "shared" or "world_readable". If that's the case then we don't
# need to check membership (as we know the server is in the room).
@@ -636,7 +655,7 @@ async def filter_events_for_server(
if event_to_history_vis[e.event_id]
not in (HistoryVisibility.SHARED, HistoryVisibility.WORLD_READABLE)
],
- server_name,
+ target_server_name,
)
to_return = []
@@ -645,6 +664,10 @@ async def filter_events_for_server(
visible = check_event_is_visible(
event_to_history_vis[e.event_id], event_to_memberships.get(e.event_id, {})
)
+
+ if e in partial_state_invisible_events:
+ visible = False
+
if visible and not erased:
to_return.append(e)
elif redact:
|
