1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
|
# -*- coding: utf-8 -*-
# Copyright 2014 - 2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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 EventTypes, Membership
from synapse.events.utils import prune_event
from synapse.util.logcontext import (
make_deferred_yieldable, preserve_fn,
)
logger = logging.getLogger(__name__)
VISIBILITY_PRIORITY = (
"world_readable",
"shared",
"invited",
"joined",
)
MEMBERSHIP_PRIORITY = (
Membership.JOIN,
Membership.INVITE,
Membership.KNOCK,
Membership.LEAVE,
Membership.BAN,
)
@defer.inlineCallbacks
def filter_events_for_client(store, user_id, events, is_peeking=False,
always_include_ids=frozenset()):
"""
Check which events a user is allowed to see
Args:
store (synapse.storage.DataStore): our datastore (can also be a worker
store)
user_id(str): user id to be checked
events(list[synapse.events.EventBase]): sequence of events to be checked
is_peeking(bool): should be True if:
* the user is not currently a member of the room, and:
* the user has not been a member of the room since the given
events
always_include_ids (set(event_id)): set of event ids to specifically
include (unless sender is ignored)
Returns:
Deferred[list[synapse.events.EventBase]]
"""
types = (
(EventTypes.RoomHistoryVisibility, ""),
(EventTypes.Member, user_id),
)
event_id_to_state = yield store.get_state_for_events(
frozenset(e.event_id for e in events),
types=types,
)
forgotten = yield make_deferred_yieldable(defer.gatherResults([
defer.maybeDeferred(
preserve_fn(store.who_forgot_in_room),
room_id,
)
for room_id in frozenset(e.room_id for e in events)
], consumeErrors=True))
# Set of membership event_ids that have been forgotten
event_id_forgotten = frozenset(
row["event_id"] for rows in forgotten for row in rows
)
ignore_dict_content = yield store.get_global_account_data_by_type_for_user(
"m.ignored_user_list", user_id,
)
# FIXME: This will explode if people upload something incorrect.
ignore_list = frozenset(
ignore_dict_content.get("ignored_users", {}).keys()
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 None
if event.event_id in always_include_ids:
return event
state = event_id_to_state[event.event_id]
# get the room_visibility at the time of the event.
visibility_event = state.get((EventTypes.RoomHistoryVisibility, ""), None)
if visibility_event:
visibility = visibility_event.content.get("history_visibility", "shared")
else:
visibility = "shared"
if visibility not in VISIBILITY_PRIORITY:
visibility = "shared"
# Always allow history visibility events on boundaries. This is done
# by setting the effective visibility to the least restrictive
# of the old vs new.
if event.type == EventTypes.RoomHistoryVisibility:
prev_content = event.unsigned.get("prev_content", {})
prev_visibility = prev_content.get("history_visibility", None)
if prev_visibility not in VISIBILITY_PRIORITY:
prev_visibility = "shared"
new_priority = VISIBILITY_PRIORITY.index(visibility)
old_priority = VISIBILITY_PRIORITY.index(prev_visibility)
if old_priority < new_priority:
visibility = prev_visibility
# likewise, if the event is the user's own membership event, use
# the 'most joined' membership
membership = None
if event.type == EventTypes.Member and event.state_key == user_id:
membership = event.content.get("membership", None)
if membership not in MEMBERSHIP_PRIORITY:
membership = "leave"
prev_content = event.unsigned.get("prev_content", {})
prev_membership = prev_content.get("membership", None)
if prev_membership not in MEMBERSHIP_PRIORITY:
prev_membership = "leave"
# Always allow the user to see their own leave events, otherwise
# they won't see the room disappear if they reject the invite
if membership == "leave" and (
prev_membership == "join" or prev_membership == "invite"
):
return event
new_priority = MEMBERSHIP_PRIORITY.index(membership)
old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
if old_priority < new_priority:
membership = prev_membership
# otherwise, get the user's membership at the time of the event.
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 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 None
elif visibility == "invited":
# user can also see the event if they were *invited* at the time
# of the event.
return (
event if membership == Membership.INVITE else None
)
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. We just treat it as though they
# never joined, and restrict access.
return None
# 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))
|
