228 lines
8.0 KiB
Python
228 lines
8.0 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014 - 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import itertools
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import logging
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import operator
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from twisted.internet import defer
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from synapse.api.constants import EventTypes, Membership
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from synapse.events.utils import prune_event
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from synapse.util.logcontext import make_deferred_yieldable, preserve_fn
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logger = logging.getLogger(__name__)
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VISIBILITY_PRIORITY = (
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"world_readable",
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"shared",
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"invited",
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"joined",
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)
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MEMBERSHIP_PRIORITY = (
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Membership.JOIN,
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Membership.INVITE,
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Membership.KNOCK,
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Membership.LEAVE,
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Membership.BAN,
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)
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@defer.inlineCallbacks
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def filter_events_for_client(store, user_id, events, is_peeking=False,
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always_include_ids=frozenset()):
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"""
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Check which events a user is allowed to see
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Args:
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store (synapse.storage.DataStore): our datastore (can also be a worker
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store)
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user_id(str): user id to be checked
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events(list[synapse.events.EventBase]): sequence of events to be checked
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is_peeking(bool): should be True if:
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* the user is not currently a member of the room, and:
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* the user has not been a member of the room since the given
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events
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always_include_ids (set(event_id)): set of event ids to specifically
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include (unless sender is ignored)
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Returns:
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Deferred[list[synapse.events.EventBase]]
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"""
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types = (
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(EventTypes.RoomHistoryVisibility, ""),
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(EventTypes.Member, user_id),
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)
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event_id_to_state = yield store.get_state_for_events(
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frozenset(e.event_id for e in events),
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types=types,
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)
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forgotten = yield make_deferred_yieldable(defer.gatherResults([
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defer.maybeDeferred(
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preserve_fn(store.who_forgot_in_room),
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room_id,
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)
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for room_id in frozenset(e.room_id for e in events)
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], consumeErrors=True))
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# Set of membership event_ids that have been forgotten
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event_id_forgotten = frozenset(
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row["event_id"] for rows in forgotten for row in rows
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)
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ignore_dict_content = yield store.get_global_account_data_by_type_for_user(
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"m.ignored_user_list", user_id,
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)
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# FIXME: This will explode if people upload something incorrect.
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ignore_list = frozenset(
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ignore_dict_content.get("ignored_users", {}).keys()
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if ignore_dict_content else []
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)
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erased_senders = yield store.are_users_erased((e.sender for e in events))
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def allowed(event):
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"""
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Args:
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event (synapse.events.EventBase): event to check
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Returns:
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None|EventBase:
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None if the user cannot see this event at all
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a redacted copy of the event if they can only see a redacted
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version
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the original event if they can see it as normal.
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"""
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if not event.is_state() and event.sender in ignore_list:
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return None
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if event.event_id in always_include_ids:
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return event
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state = event_id_to_state[event.event_id]
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# get the room_visibility at the time of the event.
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visibility_event = state.get((EventTypes.RoomHistoryVisibility, ""), None)
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if visibility_event:
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visibility = visibility_event.content.get("history_visibility", "shared")
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else:
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visibility = "shared"
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if visibility not in VISIBILITY_PRIORITY:
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visibility = "shared"
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# Always allow history visibility events on boundaries. This is done
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# by setting the effective visibility to the least restrictive
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# of the old vs new.
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if event.type == EventTypes.RoomHistoryVisibility:
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prev_content = event.unsigned.get("prev_content", {})
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prev_visibility = prev_content.get("history_visibility", None)
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if prev_visibility not in VISIBILITY_PRIORITY:
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prev_visibility = "shared"
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new_priority = VISIBILITY_PRIORITY.index(visibility)
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old_priority = VISIBILITY_PRIORITY.index(prev_visibility)
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if old_priority < new_priority:
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visibility = prev_visibility
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# likewise, if the event is the user's own membership event, use
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# the 'most joined' membership
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membership = None
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if event.type == EventTypes.Member and event.state_key == user_id:
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membership = event.content.get("membership", None)
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if membership not in MEMBERSHIP_PRIORITY:
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membership = "leave"
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prev_content = event.unsigned.get("prev_content", {})
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prev_membership = prev_content.get("membership", None)
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if prev_membership not in MEMBERSHIP_PRIORITY:
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prev_membership = "leave"
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# Always allow the user to see their own leave events, otherwise
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# they won't see the room disappear if they reject the invite
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if membership == "leave" and (
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prev_membership == "join" or prev_membership == "invite"
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):
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return event
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new_priority = MEMBERSHIP_PRIORITY.index(membership)
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old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
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if old_priority < new_priority:
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membership = prev_membership
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# otherwise, get the user's membership at the time of the event.
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if membership is None:
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membership_event = state.get((EventTypes.Member, user_id), None)
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if membership_event:
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# XXX why do we do this?
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# https://github.com/matrix-org/synapse/issues/3350
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if membership_event.event_id not in event_id_forgotten:
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membership = membership_event.membership
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# if the user was a member of the room at the time of the event,
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# they can see it.
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if membership == Membership.JOIN:
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return event
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# otherwise, it depends on the room visibility.
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if visibility == "joined":
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# we weren't a member at the time of the event, so we can't
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# see this event.
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return None
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elif visibility == "invited":
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# user can also see the event if they were *invited* at the time
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# of the event.
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return (
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event if membership == Membership.INVITE else None
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)
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elif visibility == "shared" and is_peeking:
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# if the visibility is shared, users cannot see the event unless
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# they have *subequently* joined the room (or were members at the
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# time, of course)
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#
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# XXX: if the user has subsequently joined and then left again,
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# ideally we would share history up to the point they left. But
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# we don't know when they left. We just treat it as though they
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# never joined, and restrict access.
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return None
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# the visibility is either shared or world_readable, and the user was
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# not a member at the time. We allow it, provided the original sender
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# has not requested their data to be erased, in which case, we return
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# a redacted version.
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if erased_senders[event.sender]:
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return prune_event(event)
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return event
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# check each event: gives an iterable[None|EventBase]
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filtered_events = itertools.imap(allowed, events)
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# remove the None entries
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filtered_events = filter(operator.truth, filtered_events)
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# we turn it into a list before returning it.
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defer.returnValue(list(filtered_events))
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