Merge pull request #7066 from matrix-org/babolivier/dummy_events_state

Skip the correct visibility checks when checking the visibility of the state at a given event
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Brendan Abolivier 2020-03-11 20:07:58 +00:00 committed by GitHub
commit bd5e555b0d
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3 changed files with 32 additions and 26 deletions

1
changelog.d/7066.bugfix Normal file
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@ -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.

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@ -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]

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@ -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
# 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
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
# 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")
# 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 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.origin_server_ts < oldest_allowed_ts:
return None
if event.event_id in always_include_ids:
return event