summary refs log tree commit diff
path: root/synapse/handlers/federation.py
blob: e5deb8a9ef5c9ddc23526d1ce411a5ea527600fa (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
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
# -*- 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.

"""Contains handlers for federation events."""

from ._base import BaseHandler

from synapse.events.snapshot import EventContext
from synapse.events.utils import prune_event
from synapse.api.errors import (
    AuthError, FederationError, SynapseError, StoreError,
)
from synapse.api.events.room import RoomMemberEvent, RoomCreateEvent
from synapse.api.constants import Membership
from synapse.util.logutils import log_function
from synapse.util.async import run_on_reactor
from synapse.crypto.event_signing import (
    compute_event_signature, check_event_content_hash,
    add_hashes_and_signatures,
)
from syutil.jsonutil import encode_canonical_json

from twisted.internet import defer

import logging


logger = logging.getLogger(__name__)


class FederationHandler(BaseHandler):
    """Handles events that originated from federation.
        Responsible for:
        a) handling received Pdus before handing them on as Events to the rest
        of the home server (including auth and state conflict resoultion)
        b) converting events that were produced by local clients that may need
        to be sent to remote home servers.
        c) doing the necessary dances to invite remote users and join remote
        rooms.
    """

    def __init__(self, hs):
        super(FederationHandler, self).__init__(hs)

        self.distributor.observe(
            "user_joined_room",
            self._on_user_joined
        )

        self.waiting_for_join_list = {}

        self.store = hs.get_datastore()
        self.replication_layer = hs.get_replication_layer()
        self.state_handler = hs.get_state_handler()
        # self.auth_handler = gs.get_auth_handler()
        self.server_name = hs.hostname
        self.keyring = hs.get_keyring()

        self.lock_manager = hs.get_room_lock_manager()

        self.replication_layer.set_handler(self)

        # When joining a room we need to queue any events for that room up
        self.room_queues = {}

    @log_function
    @defer.inlineCallbacks
    def handle_new_event(self, event, snapshot, destinations):
        """ Takes in an event from the client to server side, that has already
        been authed and handled by the state module, and sends it to any
        remote home servers that may be interested.

        Args:
            event
            snapshot (.storage.Snapshot): THe snapshot the event happened after

        Returns:
            Deferred: Resolved when it has successfully been queued for
            processing.
        """

        yield run_on_reactor()

        yield self.replication_layer.send_pdu(event, destinations)

    @log_function
    @defer.inlineCallbacks
    def on_receive_pdu(self, origin, pdu, backfilled, state=None):
        """ Called by the ReplicationLayer when we have a new pdu. We need to
        do auth checks and put it through the StateHandler.
        """
        event = pdu

        logger.debug("Got event: %s", event.event_id)

        # If we are currently in the process of joining this room, then we
        # queue up events for later processing.
        if event.room_id in self.room_queues:
            self.room_queues[event.room_id].append((pdu, origin))
            return

        logger.debug("Processing event: %s", event.event_id)

        redacted_event = prune_event(event)

        redacted_pdu_json = redacted_event.get_pdu_json()
        try:
            yield self.keyring.verify_json_for_server(
                event.origin, redacted_pdu_json
            )
        except SynapseError as e:
            logger.warn(
                "Signature check failed for %s redacted to %s",
                encode_canonical_json(pdu.get_pdu_json()),
                encode_canonical_json(redacted_pdu_json),
            )
            raise FederationError(
                "ERROR",
                e.code,
                e.msg,
                affected=event.event_id,
            )

        if not check_event_content_hash(event):
            logger.warn(
                "Event content has been tampered, redacting %s, %s",
                event.event_id, encode_canonical_json(event.get_full_dict())
            )
            event = redacted_event

        logger.debug("Event: %s", event)

        # FIXME (erikj): Awful hack to make the case where we are not currently
        # in the room work
        current_state = None
        is_in_room = yield self.auth.check_host_in_room(
            event.room_id,
            self.server_name
        )
        if not is_in_room and not event.internal_metadata.outlier:
            logger.debug("Got event for room we're not in.")

            replication_layer = self.replication_layer
            auth_chain = yield replication_layer.get_event_auth(
                origin,
                context=event.room_id,
                event_id=event.event_id,
            )

            for e in auth_chain:
                e.internal_metadata.outlier = True
                try:
                    yield self._handle_new_event(e, fetch_missing=False)
                except:
                    logger.exception(
                        "Failed to parse auth event %s",
                        e.event_id,
                    )

            if not state:
                state = yield replication_layer.get_state_for_context(
                    origin,
                    context=event.room_id,
                    event_id=event.event_id,
                )

            current_state = state

        if state:
            for e in state:
                e.internal_metadata.outlier = True
                try:
                    yield self._handle_new_event(e)
                except:
                    logger.exception(
                        "Failed to parse state event %s",
                        e.event_id,
                    )

        try:
            yield self._handle_new_event(
                event,
                state=state,
                backfilled=backfilled,
                current_state=current_state,
            )
        except AuthError as e:
            raise FederationError(
                "ERROR",
                e.code,
                e.msg,
                affected=event.event_id,
            )
            
        # if we're receiving valid events from an origin,
        # it's probably a good idea to mark it as not in retry-state
        # for sending (although this is a bit of a leap)
        retry_timings = yield self.store.get_destination_retry_timings(origin)
        if (retry_timings and retry_timings.retry_last_ts):
            self.store.set_destination_retry_timings(origin, 0, 0)

        room = yield self.store.get_room(event.room_id)

        if not room:
            try:
                yield self.store.store_room(
                    room_id=event.room_id,
                    room_creator_user_id="",
                    is_public=False,
                )
            except StoreError:
                logger.exception("Failed to store room.")

        if not backfilled:
            extra_users = []
            if event.type == RoomMemberEvent.TYPE:
                target_user_id = event.state_key
                target_user = self.hs.parse_userid(target_user_id)
                extra_users.append(target_user)

            yield self.notifier.on_new_room_event(
                event, extra_users=extra_users
            )

        if event.type == RoomMemberEvent.TYPE:
            if event.membership == Membership.JOIN:
                user = self.hs.parse_userid(event.state_key)
                yield self.distributor.fire(
                    "user_joined_room", user=user, room_id=event.room_id
                )

    @log_function
    @defer.inlineCallbacks
    def backfill(self, dest, room_id, limit):
        """ Trigger a backfill request to `dest` for the given `room_id`
        """
        extremities = yield self.store.get_oldest_events_in_room(room_id)

        pdus = yield self.replication_layer.backfill(
            dest,
            room_id,
            limit,
            extremities=extremities,
        )

        events = []

        for pdu in pdus:
            event = pdu

            # FIXME (erikj): Not sure this actually works :/
            context = EventContext()
            yield self.state_handler.annotate_context_with_state(event, context)

            events.append(
                (event, context)
            )

            yield self.store.persist_event(
                event,
                context=context,
                backfilled=True
            )

        defer.returnValue(events)

    @defer.inlineCallbacks
    def send_invite(self, target_host, event):
        """ Sends the invite to the remote server for signing.

        Invites must be signed by the invitee's server before distribution.
        """
        pdu = yield self.replication_layer.send_invite(
            destination=target_host,
            context=event.room_id,
            event_id=event.event_id,
            pdu=event
        )

        defer.returnValue(pdu)

    @defer.inlineCallbacks
    def on_event_auth(self, event_id):
        auth = yield self.store.get_auth_chain(event_id)

        for event in auth:
            event.signatures.update(
                compute_event_signature(
                    event,
                    self.hs.hostname,
                    self.hs.config.signing_key[0]
                )
            )

        defer.returnValue([e for e in auth])

    @log_function
    @defer.inlineCallbacks
    def do_invite_join(self, target_host, room_id, joinee, content, snapshot):
        """ Attempts to join the `joinee` to the room `room_id` via the
        server `target_host`.

        This first triggers a /make_join/ request that returns a partial
        event that we can fill out and sign. This is then sent to the
        remote server via /send_join/ which responds with the state at that
        event and the auth_chains.

        We suspend processing of any received events from this room until we
        have finished processing the join.
        """
        logger.debug("Joining %s to %s", joinee, room_id)

        pdu = yield self.replication_layer.make_join(
            target_host,
            room_id,
            joinee
        )

        logger.debug("Got response to make_join: %s", pdu)

        event = pdu

        # We should assert some things.
        assert(event.type == RoomMemberEvent.TYPE)
        assert(event.user_id == joinee)
        assert(event.state_key == joinee)
        assert(event.room_id == room_id)

        event.internal_metadata.outlier = False

        self.room_queues[room_id] = []

        builder = self.event_builder_factory.new(
            event.get_pdu_json()
        )

        try:
            builder.event_id = self.event_factory.create_event_id()
            builder.origin = self.hs.hostname
            builder.content = content

            if not hasattr(event, "signatures"):
                builder.signatures = {}

            add_hashes_and_signatures(
                builder,
                self.hs.hostname,
                self.hs.config.signing_key[0],
            )

            new_event = builder.build()

            ret = yield self.replication_layer.send_join(
                target_host,
                new_event
            )

            state = ret["state"]
            auth_chain = ret["auth_chain"]
            auth_chain.sort(key=lambda e: e.depth)

            logger.debug("do_invite_join auth_chain: %s", auth_chain)
            logger.debug("do_invite_join state: %s", state)

            logger.debug("do_invite_join event: %s", new_event)

            try:
                yield self.store.store_room(
                    room_id=room_id,
                    room_creator_user_id="",
                    is_public=False
                )
            except:
                # FIXME
                pass

            for e in auth_chain:
                e.internal_metadata.outlier = True
                try:
                    yield self._handle_new_event(e, fetch_missing=False)
                except:
                    logger.exception(
                        "Failed to parse auth event %s",
                        e.event_id,
                    )

            for e in state:
                # FIXME: Auth these.
                e.internal_metadata.outlier = True
                try:
                    yield self._handle_new_event(
                        e,
                        fetch_missing=True
                    )
                except:
                    logger.exception(
                        "Failed to parse state event %s",
                        e.event_id,
                    )

            yield self._handle_new_event(
                new_event,
                state=state,
                current_state=state,
            )

            yield self.notifier.on_new_room_event(
                new_event, extra_users=[joinee]
            )

            logger.debug("Finished joining %s to %s", joinee, room_id)
        finally:
            room_queue = self.room_queues[room_id]
            del self.room_queues[room_id]

            for p, origin in room_queue:
                try:
                    self.on_receive_pdu(origin, p, backfilled=False)
                except:
                    logger.exception("Couldn't handle pdu")

        defer.returnValue(True)

    @defer.inlineCallbacks
    @log_function
    def on_make_join_request(self, room_id, user_id):
        """ We've received a /make_join/ request, so we create a partial
        join event for the room and return that. We don *not* persist or
        process it until the other server has signed it and sent it back.
        """
        builder = self.event_builder_factory.new({
            "type": RoomMemberEvent.TYPE,
            "content": {"membership": Membership.JOIN},
            "room_id": room_id,
            "sender": user_id,
            "state_key": user_id,
        })

        event, context = yield self._create_new_client_event(
            builder=builder,
        )

        self.auth.check(event, auth_events=context.auth_events)

        pdu = event

        defer.returnValue(pdu)

    @defer.inlineCallbacks
    @log_function
    def on_send_join_request(self, origin, pdu):
        """ We have received a join event for a room. Fully process it and
        respond with the current state and auth chains.
        """
        event = pdu

        logger.debug(
            "on_send_join_request: Got event: %s, signatures: %s",
            event.event_id,
            event.signatures,
        )

        event.internal_metadata.outlier = False

        context = yield self._handle_new_event(event)

        logger.debug(
            "on_send_join_request: After _handle_new_event: %s, sigs: %s",
            event.event_id,
            event.signatures,
        )

        extra_users = []
        if event.type == RoomMemberEvent.TYPE:
            target_user_id = event.state_key
            target_user = self.hs.parse_userid(target_user_id)
            extra_users.append(target_user)

        yield self.notifier.on_new_room_event(
            event, extra_users=extra_users
        )

        if event.type == RoomMemberEvent.TYPE:
            if event.content["membership"] == Membership.JOIN:
                user = self.hs.parse_userid(event.state_key)
                yield self.distributor.fire(
                    "user_joined_room", user=user, room_id=event.room_id
                )

        new_pdu = event

        destinations = set()

        for k, s in context.current_state.items():
            try:
                if k[0] == RoomMemberEvent.TYPE:
                    if s.content["membership"] == Membership.JOIN:
                        destinations.add(
                            self.hs.parse_userid(s.state_key).domain
                        )
            except:
                logger.warn(
                    "Failed to get destination from event %s", s.event_id
                )

        logger.debug(
            "on_send_join_request: Sending event: %s, signatures: %s",
            event.event_id,
            event.signatures,
        )

        yield self.replication_layer.send_pdu(new_pdu, destinations)

        auth_chain = yield self.store.get_auth_chain(event.event_id)

        defer.returnValue({
            "state": context.current_state.values(),
            "auth_chain": auth_chain,
        })

    @defer.inlineCallbacks
    def on_invite_request(self, origin, pdu):
        """ We've got an invite event. Process and persist it. Sign it.

        Respond with the now signed event.
        """
        event = pdu

        context = EventContext()

        event.internal_metadata.outlier = True

        event.signatures.update(
            compute_event_signature(
                event,
                self.hs.hostname,
                self.hs.config.signing_key[0]
            )
        )

        yield self.state_handler.annotate_context_with_state(event, context)

        yield self.store.persist_event(
            event,
            context=context,
            backfilled=False,
        )

        target_user = self.hs.parse_userid(event.state_key)
        yield self.notifier.on_new_room_event(
            event, extra_users=[target_user],
        )

        defer.returnValue(event)

    @defer.inlineCallbacks
    def get_state_for_pdu(self, origin, room_id, event_id):
        yield run_on_reactor()

        in_room = yield self.auth.check_host_in_room(room_id, origin)
        if not in_room:
            raise AuthError(403, "Host not in room.")

        state_groups = yield self.store.get_state_groups(
            [event_id]
        )

        if state_groups:
            _, state = state_groups.items().pop()
            results = {
                (e.type, e.state_key): e for e in state
            }

            event = yield self.store.get_event(event_id)
            if hasattr(event, "state_key"):
                # Get previous state
                if hasattr(event, "replaces_state") and event.replaces_state:
                    prev_event = yield self.store.get_event(
                        event.replaces_state
                    )
                    results[(event.type, event.state_key)] = prev_event
                else:
                    del results[(event.type, event.state_key)]

            res = results.values()
            for event in res:
                event.signatures.update(
                    compute_event_signature(
                        event,
                        self.hs.hostname,
                        self.hs.config.signing_key[0]
                    )
                )

            defer.returnValue(res)
        else:
            defer.returnValue([])

    @defer.inlineCallbacks
    @log_function
    def on_backfill_request(self, origin, context, pdu_list, limit):
        in_room = yield self.auth.check_host_in_room(context, origin)
        if not in_room:
            raise AuthError(403, "Host not in room.")

        events = yield self.store.get_backfill_events(
            context,
            pdu_list,
            limit
        )

        defer.returnValue(events)

    @defer.inlineCallbacks
    @log_function
    def get_persisted_pdu(self, origin, event_id, do_auth=True):
        """ Get a PDU from the database with given origin and id.

        Returns:
            Deferred: Results in a `Pdu`.
        """
        event = yield self.store.get_event(
            event_id,
            allow_none=True,
        )

        if event:
            # FIXME: This is a temporary work around where we occasionally
            # return events slightly differently than when they were
            # originally signed
            event.signatures.update(
                compute_event_signature(
                    event,
                    self.hs.hostname,
                    self.hs.config.signing_key[0]
                )
            )

            if do_auth:
                in_room = yield self.auth.check_host_in_room(
                    event.room_id,
                    origin
                )
                if not in_room:
                    raise AuthError(403, "Host not in room.")

            defer.returnValue(event)
        else:
            defer.returnValue(None)

    @log_function
    def get_min_depth_for_context(self, context):
        return self.store.get_min_depth(context)

    @log_function
    def _on_user_joined(self, user, room_id):
        waiters = self.waiting_for_join_list.get(
            (user.to_string(), room_id),
            []
        )
        while waiters:
            waiters.pop().callback(None)

    @defer.inlineCallbacks
    def _handle_new_event(self, event, state=None, backfilled=False,
                          current_state=None, fetch_missing=True):
        context = EventContext()

        logger.debug(
            "_handle_new_event: Before annotate: %s, sigs: %s",
            event.event_id, event.signatures,
        )

        yield self.state_handler.annotate_context_with_state(
            event,
            context,
            old_state=state
        )

        logger.debug(
            "_handle_new_event: Before auth fetch: %s, sigs: %s",
            event.event_id, event.signatures,
        )

        is_new_state = not event.internal_metadata.is_outlier()

        known_ids = set(
            [s.event_id for s in context.auth_events.values()]
        )
        for e_id, _ in event.auth_events:
            if e_id not in known_ids:
                e = yield self.store.get_event(
                    e_id, allow_none=True,
                )

                if not e:
                    # TODO: Do some conflict res to make sure that we're
                    # not the ones who are wrong.
                    logger.info(
                        "Rejecting %s as %s not in db or %s",
                        event.event_id, e_id, known_ids,
                    )
                    raise AuthError(403, "Auth events are stale")

                context.auth_events[(e.type, e.state_key)] = e

        logger.debug(
            "_handle_new_event: Before hack: %s, sigs: %s",
            event.event_id, event.signatures,
        )

        if event.type == RoomMemberEvent.TYPE and not event.auth_events:
            if len(event.prev_events) == 1:
                c = yield self.store.get_event(event.prev_events[0][0])
                if c.type == RoomCreateEvent.TYPE:
                    context.auth_events[(c.type, c.state_key)] = c

        logger.debug(
            "_handle_new_event: Before auth check: %s, sigs: %s",
            event.event_id, event.signatures,
        )

        self.auth.check(event, auth_events=context.auth_events)

        logger.debug(
            "_handle_new_event: Before persist_event: %s, sigs: %s",
            event.event_id, event.signatures,
        )

        yield self.store.persist_event(
            event,
            context=context,
            backfilled=backfilled,
            is_new_state=(is_new_state and not backfilled),
            current_state=current_state,
        )

        logger.debug(
            "_handle_new_event: After persist_event: %s, sigs: %s",
            event.event_id, event.signatures,
        )

        defer.returnValue(context)