summary refs log tree commit diff
path: root/synapse/api/auth.py
blob: 9bfd25c86e70bdc3e51f4de4d0bd414630944a42 (plain) (blame)
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
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
# -*- coding: utf-8 -*-
# Copyright 2014 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.

"""This module contains classes for authenticating the user."""

from twisted.internet import defer

from synapse.api.constants import Membership, JoinRules
from synapse.api.errors import AuthError, StoreError, Codes, SynapseError
from synapse.api.events.room import (
    RoomMemberEvent, RoomPowerLevelsEvent, RoomRedactionEvent,
)
from synapse.util.logutils import log_function

import logging

logger = logging.getLogger(__name__)


class Auth(object):

    def __init__(self, hs):
        self.hs = hs
        self.store = hs.get_datastore()

    @defer.inlineCallbacks
    def check(self, event, snapshot, raises=False):
        """ Checks if this event is correctly authed.

        Returns:
            True if the auth checks pass.
        Raises:
            AuthError if there was a problem authorising this event. This will
            be raised only if raises=True.
        """
        try:
            if hasattr(event, "room_id"):
                is_state = hasattr(event, "state_key")

                if event.type == RoomMemberEvent.TYPE:
                    yield self._can_replace_state(event)
                    allowed = yield self.is_membership_change_allowed(event)
                    defer.returnValue(allowed)
                    return

                self._check_joined_room(
                    member=snapshot.membership_state,
                    user_id=snapshot.user_id,
                    room_id=snapshot.room_id,
                )

                if is_state:
                    # TODO (erikj): This really only should be called for *new*
                    # state
                    yield self._can_add_state(event)
                    yield self._can_replace_state(event)
                else:
                    yield self._can_send_event(event)

                if event.type == RoomPowerLevelsEvent.TYPE:
                    yield self._check_power_levels(event)

                if event.type == RoomRedactionEvent.TYPE:
                    yield self._check_redaction(event)

                defer.returnValue(True)
            else:
                raise AuthError(500, "Unknown event: %s" % event)
        except AuthError as e:
            logger.info("Event auth check failed on event %s with msg: %s",
                        event, e.msg)
            if raises:
                raise e
        defer.returnValue(False)

    @defer.inlineCallbacks
    def check_joined_room(self, room_id, user_id):
        try:
            member = yield self.store.get_room_member(
                room_id=room_id,
                user_id=user_id
            )
            self._check_joined_room(member, user_id, room_id)
            defer.returnValue(member)
        except AttributeError:
            pass
        defer.returnValue(None)

    def _check_joined_room(self, member, user_id, room_id):
        if not member or member.membership != Membership.JOIN:
            raise AuthError(403, "User %s not in room %s (%s)" % (
                user_id, room_id, repr(member)
            ))

    @defer.inlineCallbacks
    def is_membership_change_allowed(self, event):
        target_user_id = event.state_key

        # does this room even exist
        room = yield self.store.get_room(event.room_id)
        if not room:
            raise AuthError(403, "Room does not exist")

        # get info about the caller
        try:
            caller = yield self.store.get_room_member(
                user_id=event.user_id,
                room_id=event.room_id)
        except:
            caller = None
        caller_in_room = caller and caller.membership == "join"

        # get info about the target
        try:
            target = yield self.store.get_room_member(
                user_id=target_user_id,
                room_id=event.room_id)
        except:
            target = None
        target_in_room = target and target.membership == "join"

        membership = event.content["membership"]

        join_rule = yield self.store.get_room_join_rule(event.room_id)
        if not join_rule:
            join_rule = JoinRules.INVITE

        if Membership.INVITE == membership:
            # TODO (erikj): We should probably handle this more intelligently
            # PRIVATE join rules.

            # Invites are valid iff caller is in the room and target isn't.
            if not caller_in_room:  # caller isn't joined
                raise AuthError(403, "You are not in room %s." % event.room_id)
            elif target_in_room:  # the target is already in the room.
                raise AuthError(403, "%s is already in the room." %
                                     target_user_id)
        elif Membership.JOIN == membership:
            # Joins are valid iff caller == target and they were:
            # invited: They are accepting the invitation
            # joined: It's a NOOP
            if event.user_id != target_user_id:
                raise AuthError(403, "Cannot force another user to join.")
            elif join_rule == JoinRules.PUBLIC or room.is_public:
                pass
            elif join_rule == JoinRules.INVITE:
                if (
                    not caller or caller.membership not in
                    [Membership.INVITE, Membership.JOIN]
                ):
                    raise AuthError(403, "You are not invited to this room.")
            else:
                # TODO (erikj): may_join list
                # TODO (erikj): private rooms
                raise AuthError(403, "You are not allowed to join this room")
        elif Membership.LEAVE == membership:
            # TODO (erikj): Implement kicks.

            if not caller_in_room:  # trying to leave a room you aren't joined
                raise AuthError(403, "You are not in room %s." % event.room_id)
            elif target_user_id != event.user_id:
                user_level = yield self.store.get_power_level(
                    event.room_id,
                    event.user_id,
                )
                _, kick_level, _ = yield self.store.get_ops_levels(event.room_id)

                if kick_level:
                    kick_level = int(kick_level)
                else:
                    kick_level = 50

                if user_level < kick_level:
                    raise AuthError(
                        403, "You cannot kick user %s." % target_user_id
                    )
        elif Membership.BAN == membership:
            user_level = yield self.store.get_power_level(
                event.room_id,
                event.user_id,
            )

            ban_level, _, _  = yield self.store.get_ops_levels(event.room_id)

            if ban_level:
                ban_level = int(ban_level)
            else:
                ban_level = 50  # FIXME (erikj): What should we do here?

            if user_level < ban_level:
                raise AuthError(403, "You don't have permission to ban")
        else:
            raise AuthError(500, "Unknown membership %s" % membership)

        defer.returnValue(True)

    def get_user_by_req(self, request):
        """ Get a registered user's ID.

        Args:
            request - An HTTP request with an access_token query parameter.
        Returns:
            UserID : User ID object of the user making the request
        Raises:
            AuthError if no user by that token exists or the token is invalid.
        """
        # Can optionally look elsewhere in the request (e.g. headers)
        try:
            return self.get_user_by_token(request.args["access_token"][0])
        except KeyError:
            raise AuthError(403, "Missing access token.")

    @defer.inlineCallbacks
    def get_user_by_token(self, token):
        """ Get a registered user's ID.

        Args:
            token (str)- The access token to get the user by.
        Returns:
            UserID : User ID object of the user who has that access token.
        Raises:
            AuthError if no user by that token exists or the token is invalid.
        """
        try:
            user_id = yield self.store.get_user_by_token(token=token)
            if not user_id:
                raise StoreError()
            defer.returnValue(self.hs.parse_userid(user_id))
        except StoreError:
            raise AuthError(403, "Unrecognised access token.",
                            errcode=Codes.UNKNOWN_TOKEN)

    @defer.inlineCallbacks
    @log_function
    def _can_send_event(self, event):
        send_level = yield self.store.get_send_event_level(event.room_id)

        if send_level:
            send_level = int(send_level)
        else:
            send_level = 0

        user_level = yield self.store.get_power_level(
            event.room_id,
            event.user_id,
        )

        if user_level:
            user_level = int(user_level)
        else:
            user_level = 0

        if user_level < send_level:
            raise AuthError(
                403, "You don't have permission to post to the room"
            )

        defer.returnValue(True)

    @defer.inlineCallbacks
    def _can_add_state(self, event):
        add_level = yield self.store.get_add_state_level(event.room_id)

        if not add_level:
            defer.returnValue(True)

        add_level = int(add_level)

        user_level = yield self.store.get_power_level(
            event.room_id,
            event.user_id,
        )

        user_level = int(user_level)

        if user_level < add_level:
            raise AuthError(
                403, "You don't have permission to add state to the room"
            )

        defer.returnValue(True)

    @defer.inlineCallbacks
    def _can_replace_state(self, event):
        current_state = yield self.store.get_current_state(
            event.room_id,
            event.type,
            event.state_key,
        )

        if current_state:
            current_state = current_state[0]

        user_level = yield self.store.get_power_level(
            event.room_id,
            event.user_id,
        )

        if user_level:
            user_level = int(user_level)
        else:
            user_level = 0

        logger.debug(
            "Checking power level for %s, %s", event.user_id, user_level
        )
        if current_state and hasattr(current_state, "required_power_level"):
            req = current_state.required_power_level

            logger.debug("Checked power level for %s, %s", event.user_id, req)
            if user_level < req:
                raise AuthError(
                    403,
                    "You don't have permission to change that state"
                )

    @defer.inlineCallbacks
    def _check_redaction(self, event):
        user_level = yield self.store.get_power_level(
            event.room_id,
            event.user_id,
        )

        if user_level:
            user_level = int(user_level)
        else:
            user_level = 0

        _, _, redact_level  = yield self.store.get_ops_levels(event.room_id)

        if not redact_level:
            redact_level = 50

        if user_level < redact_level:
            raise AuthError(
                403,
                "You don't have permission to redact events"
            )

    @defer.inlineCallbacks
    def _check_power_levels(self, event):
        for k, v in event.content.items():
            if k == "default":
                continue

            # FIXME (erikj): We don't want hsob_Ts in content.
            if k == "hsob_ts":
                continue

            try:
                self.hs.parse_userid(k)
            except:
                raise SynapseError(400, "Not a valid user_id: %s" % (k,))

            try:
                int(v)
            except:
                raise SynapseError(400, "Not a valid power level: %s" % (v,))

        current_state = yield self.store.get_current_state(
            event.room_id,
            event.type,
            event.state_key,
        )

        if not current_state:
            return
        else:
            current_state = current_state[0]

        user_level = yield self.store.get_power_level(
            event.room_id,
            event.user_id,
        )

        if user_level:
            user_level = int(user_level)
        else:
            user_level = 0

        old_list = current_state.content

        # FIXME (erikj)
        old_people = {k: v for k, v in old_list.items() if k.startswith("@")}
        new_people = {
            k: v for k, v in event.content.items()
            if k.startswith("@")
        }

        removed = set(old_people.keys()) - set(new_people.keys())
        added = set(new_people.keys()) - set(old_people.keys())
        same = set(old_people.keys()) & set(new_people.keys())

        for r in removed:
            if int(old_list[r]) > user_level:
                raise AuthError(
                    403,
                    "You don't have permission to remove user: %s" % (r, )
                )

        for n in added:
            if int(event.content[n]) > user_level:
                raise AuthError(
                    403,
                    "You don't have permission to add ops level greater "
                    "than your own"
                )

        for s in same:
            if int(event.content[s]) != int(old_list[s]):
                if int(event.content[s]) > user_level:
                    raise AuthError(
                        403,
                        "You don't have permission to add ops level greater "
                        "than your own"
                    )

        if "default" in old_list:
            old_default = int(old_list["default"])

            if old_default > user_level:
                raise AuthError(
                    403,
                    "You don't have permission to add ops level greater than "
                    "your own"
                )

            if "default" in event.content:
                new_default = int(event.content["default"])

                if new_default > user_level:
                    raise AuthError(
                        403,
                        "You don't have permission to add ops level greater "
                        "than your own"
                    )