diff --git a/changelog.d/7066.bugfix b/changelog.d/7066.bugfix
new file mode 100644
index 0000000000..94bb096287
--- /dev/null
+++ b/changelog.d/7066.bugfix
@@ -0,0 +1 @@
+Fix a bug that would cause Synapse to respond with an error about event visibility if a client tried to request the state of a room at a given token.
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 0c84c6cec4..b743fc2dcc 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -160,7 +160,7 @@ class MessageHandler(object):
raise NotFoundError("Can't find event for token %s" % (at_token,))
visible_events = yield filter_events_for_client(
- self.storage, user_id, last_events, apply_retention_policies=False
+ self.storage, user_id, last_events, filter_send_to_client=False
)
event = last_events[0]
diff --git a/synapse/visibility.py b/synapse/visibility.py
index a48a4f3dfe..bab41182b9 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -49,7 +49,7 @@ def filter_events_for_client(
events,
is_peeking=False,
always_include_ids=frozenset(),
- apply_retention_policies=True,
+ filter_send_to_client=True,
):
"""
Check which events a user is allowed to see. If the user can see the event but its
@@ -65,10 +65,9 @@ def filter_events_for_client(
events
always_include_ids (set(event_id)): set of event ids to specifically
include (unless sender is ignored)
- apply_retention_policies (bool): Whether to filter out events that's older than
- allowed by the room's retention policy. Useful when this function is called
- to e.g. check whether a user should be allowed to see the state at a given
- event rather than to know if it should send an event to a user's client(s).
+ filter_send_to_client (bool): Whether we're checking an event that's going to be
+ sent to a client. This might not always be the case since this function can
+ also be called to check whether a user can see the state at a given point.
Returns:
Deferred[list[synapse.events.EventBase]]
@@ -96,7 +95,7 @@ def filter_events_for_client(
erased_senders = yield storage.main.are_users_erased((e.sender for e in events))
- if apply_retention_policies:
+ if filter_send_to_client:
room_ids = {e.room_id for e in events}
retention_policies = {}
@@ -119,30 +118,36 @@ def filter_events_for_client(
the original event if they can see it as normal.
"""
- if event.type == "org.matrix.dummy_event":
- return None
-
- if not event.is_state() and event.sender in ignore_list:
- return None
-
- # Until MSC2261 has landed we can't redact malicious alias events, so for
- # now we temporarily filter out m.room.aliases entirely to mitigate
- # abuse, while we spec a better solution to advertising aliases
- # on rooms.
- if event.type == EventTypes.Aliases:
- return None
-
- # Don't try to apply the room's retention policy if the event is a state event, as
- # MSC1763 states that retention is only considered for non-state events.
- if apply_retention_policies and not event.is_state():
- retention_policy = retention_policies[event.room_id]
- max_lifetime = retention_policy.get("max_lifetime")
-
- if max_lifetime is not None:
- oldest_allowed_ts = storage.main.clock.time_msec() - max_lifetime
-
- if event.origin_server_ts < oldest_allowed_ts:
- return None
+ # Only run some checks if these events aren't about to be sent to clients. This is
+ # because, if this is not the case, we're probably only checking if the users can
+ # see events in the room at that point in the DAG, and that shouldn't be decided
+ # on those checks.
+ if filter_send_to_client:
+ if event.type == "org.matrix.dummy_event":
+ return None
+
+ if not event.is_state() and event.sender in ignore_list:
+ return None
+
+ # Until MSC2261 has landed we can't redact malicious alias events, so for
+ # now we temporarily filter out m.room.aliases entirely to mitigate
+ # abuse, while we spec a better solution to advertising aliases
+ # on rooms.
+ if event.type == EventTypes.Aliases:
+ return None
+
+ # Don't try to apply the room's retention policy if the event is a state
+ # event, as MSC1763 states that retention is only considered for non-state
+ # events.
+ if not event.is_state():
+ retention_policy = retention_policies[event.room_id]
+ max_lifetime = retention_policy.get("max_lifetime")
+
+ if max_lifetime is not None:
+ oldest_allowed_ts = storage.main.clock.time_msec() - max_lifetime
+
+ if event.origin_server_ts < oldest_allowed_ts:
+ return None
if event.event_id in always_include_ids:
return event
|
