From b6faef2ad7cf1b427f418441e50c8ca8d7c67b61 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Thu, 7 Jun 2018 12:28:03 +0100 Subject: [PATCH] Filter out erased messages Redact any messges sent by erased users. --- synapse/handlers/federation.py | 13 ++++++ synapse/visibility.py | 75 ++++++++++++++++++++++++---------- 2 files changed, 67 insertions(+), 21 deletions(-) diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index a5dee355e..6f4adf102 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -495,7 +495,20 @@ class FederationHandler(BaseHandler): for e_id, key_to_eid in event_to_state_ids.iteritems() } + erased_senders = yield self.store.are_users_erased( + e.sender for e in events, + ) + def redact_disallowed(event, state): + # if the sender has been gdpr17ed, always return a redacted + # copy of the event. + if erased_senders[event.sender]: + logger.info( + "Sender of %s has been erased, redacting", + event.event_id, + ) + return prune_event(event) + if not state: return event diff --git a/synapse/visibility.py b/synapse/visibility.py index aef4953c1..65d79cf0d 100644 --- a/synapse/visibility.py +++ b/synapse/visibility.py @@ -12,15 +12,17 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. - +import itertools import logging +import operator from twisted.internet import defer -from synapse.api.constants import Membership, EventTypes - -from synapse.util.logcontext import make_deferred_yieldable, preserve_fn - +from synapse.api.constants import EventTypes, Membership +from synapse.events.utils import prune_event +from synapse.util.logcontext import ( + make_deferred_yieldable, preserve_fn, +) logger = logging.getLogger(__name__) @@ -95,16 +97,27 @@ def filter_events_for_client(store, user_id, events, is_peeking=False, if ignore_dict_content else [] ) + erased_senders = yield store.are_users_erased((e.sender for e in events)) + def allowed(event): """ Args: event (synapse.events.EventBase): event to check + + Returns: + None|EventBase: + None if the user cannot see this event at all + + a redacted copy of the event if they can only see a redacted + version + + the original event if they can see it as normal. """ if not event.is_state() and event.sender in ignore_list: - return False + return None if event.event_id in always_include_ids: - return True + return event state = event_id_to_state[event.event_id] @@ -118,10 +131,6 @@ def filter_events_for_client(store, user_id, events, is_peeking=False, if visibility not in VISIBILITY_PRIORITY: visibility = "shared" - # if it was world_readable, it's easy: everyone can read it - if visibility == "world_readable": - return True - # Always allow history visibility events on boundaries. This is done # by setting the effective visibility to the least restrictive # of the old vs new. @@ -155,7 +164,7 @@ def filter_events_for_client(store, user_id, events, is_peeking=False, if membership == "leave" and ( prev_membership == "join" or prev_membership == "invite" ): - return True + return event new_priority = MEMBERSHIP_PRIORITY.index(membership) old_priority = MEMBERSHIP_PRIORITY.index(prev_membership) @@ -166,31 +175,55 @@ def filter_events_for_client(store, user_id, events, is_peeking=False, if membership is None: membership_event = state.get((EventTypes.Member, user_id), None) if membership_event: + # XXX why do we do this? + # https://github.com/matrix-org/synapse/issues/3350 if membership_event.event_id not in event_id_forgotten: membership = membership_event.membership # if the user was a member of the room at the time of the event, # they can see it. if membership == Membership.JOIN: - return True + return event + + # otherwise, it depends on the room visibility. if visibility == "joined": # we weren't a member at the time of the event, so we can't # see this event. - return False + return None elif visibility == "invited": # user can also see the event if they were *invited* at the time # of the event. - return membership == Membership.INVITE + return ( + event if membership == Membership.INVITE else None + ) - else: - # visibility is shared: user can also see the event if they have - # become a member since the event + elif visibility == "shared" and is_peeking: + # if the visibility is shared, users cannot see the event unless + # they have *subequently* joined the room (or were members at the + # time, of course) # # XXX: if the user has subsequently joined and then left again, # ideally we would share history up to the point they left. But - # we don't know when they left. - return not is_peeking + # we don't know when they left. We just treat it as though they + # never joined, and restrict access. + return None - defer.returnValue(list(filter(allowed, events))) + # the visibility is either shared or world_readable, and the user was + # not a member at the time. We allow it, provided the original sender + # has not requested their data to be erased, in which case, we return + # a redacted version. + if erased_senders[event.sender]: + return prune_event(event) + + return event + + # check each event: gives an iterable[None|EventBase] + filtered_events = itertools.imap(allowed, events) + + # remove the None entries + filtered_events = filter(operator.truth, filtered_events) + + # we turn it into a list before returning it. + defer.returnValue(list(filtered_events))