summary refs log tree commit diff
path: root/synapse/handlers/e2e_keys.py
blob: 9dc46aa15f75ea07f0d87ae57c46376e226a1938 (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
# -*- coding: utf-8 -*-
# Copyright 2016 OpenMarket Ltd
# Copyright 2018 New Vector 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 logging

from six import iteritems

from canonicaljson import encode_canonical_json, json

from twisted.internet import defer

from synapse.api.errors import CodeMessageException, FederationDeniedError, SynapseError
from synapse.types import UserID, get_domain_from_id
from synapse.util.logcontext import make_deferred_yieldable, run_in_background
from synapse.util.retryutils import NotRetryingDestination

logger = logging.getLogger(__name__)


class E2eKeysHandler(object):
    def __init__(self, hs):
        self.store = hs.get_datastore()
        self.federation = hs.get_federation_client()
        self.device_handler = hs.get_device_handler()
        self.is_mine = hs.is_mine
        self.clock = hs.get_clock()

        # doesn't really work as part of the generic query API, because the
        # query request requires an object POST, but we abuse the
        # "query handler" interface.
        hs.get_federation_registry().register_query_handler(
            "client_keys", self.on_federation_query_client_keys
        )

    @defer.inlineCallbacks
    def query_devices(self, query_body, timeout):
        """ Handle a device key query from a client

        {
            "device_keys": {
                "<user_id>": ["<device_id>"]
            }
        }
        ->
        {
            "device_keys": {
                "<user_id>": {
                    "<device_id>": {
                        ...
                    }
                }
            }
        }
        """
        device_keys_query = query_body.get("device_keys", {})

        # separate users by domain.
        # make a map from domain to user_id to device_ids
        local_query = {}
        remote_queries = {}

        for user_id, device_ids in device_keys_query.items():
            # we use UserID.from_string to catch invalid user ids
            if self.is_mine(UserID.from_string(user_id)):
                local_query[user_id] = device_ids
            else:
                remote_queries[user_id] = device_ids

        # First get local devices.
        failures = {}
        results = {}
        if local_query:
            local_result = yield self.query_local_devices(local_query)
            for user_id, keys in local_result.items():
                if user_id in local_query:
                    results[user_id] = keys

        # Now attempt to get any remote devices from our local cache.
        remote_queries_not_in_cache = {}
        if remote_queries:
            query_list = []
            for user_id, device_ids in iteritems(remote_queries):
                if device_ids:
                    query_list.extend((user_id, device_id) for device_id in device_ids)
                else:
                    query_list.append((user_id, None))

            user_ids_not_in_cache, remote_results = (
                yield self.store.get_user_devices_from_cache(
                    query_list
                )
            )
            for user_id, devices in iteritems(remote_results):
                user_devices = results.setdefault(user_id, {})
                for device_id, device in iteritems(devices):
                    keys = device.get("keys", None)
                    device_display_name = device.get("device_display_name", None)
                    if keys:
                        result = dict(keys)
                        unsigned = result.setdefault("unsigned", {})
                        if device_display_name:
                            unsigned["device_display_name"] = device_display_name
                        user_devices[device_id] = result

            for user_id in user_ids_not_in_cache:
                domain = get_domain_from_id(user_id)
                r = remote_queries_not_in_cache.setdefault(domain, {})
                r[user_id] = remote_queries[user_id]

        # Now fetch any devices that we don't have in our cache
        @defer.inlineCallbacks
        def do_remote_query(destination):
            destination_query = remote_queries_not_in_cache[destination]
            try:
                remote_result = yield self.federation.query_client_keys(
                    destination,
                    {"device_keys": destination_query},
                    timeout=timeout
                )

                for user_id, keys in remote_result["device_keys"].items():
                    if user_id in destination_query:
                        results[user_id] = keys

            except Exception as e:
                failures[destination] = _exception_to_failure(e)

        yield make_deferred_yieldable(defer.gatherResults([
            run_in_background(do_remote_query, destination)
            for destination in remote_queries_not_in_cache
        ], consumeErrors=True))

        defer.returnValue({
            "device_keys": results, "failures": failures,
        })

    @defer.inlineCallbacks
    def query_local_devices(self, query):
        """Get E2E device keys for local users

        Args:
            query (dict[string, list[string]|None): map from user_id to a list
                 of devices to query (None for all devices)

        Returns:
            defer.Deferred: (resolves to dict[string, dict[string, dict]]):
                 map from user_id -> device_id -> device details
        """
        local_query = []

        result_dict = {}
        for user_id, device_ids in query.items():
            # we use UserID.from_string to catch invalid user ids
            if not self.is_mine(UserID.from_string(user_id)):
                logger.warning("Request for keys for non-local user %s",
                               user_id)
                raise SynapseError(400, "Not a user here")

            if not device_ids:
                local_query.append((user_id, None))
            else:
                for device_id in device_ids:
                    local_query.append((user_id, device_id))

            # make sure that each queried user appears in the result dict
            result_dict[user_id] = {}

        results = yield self.store.get_e2e_device_keys(local_query)

        # Build the result structure, un-jsonify the results, and add the
        # "unsigned" section
        for user_id, device_keys in results.items():
            for device_id, device_info in device_keys.items():
                r = dict(device_info["keys"])
                r["unsigned"] = {}
                display_name = device_info["device_display_name"]
                if display_name is not None:
                    r["unsigned"]["device_display_name"] = display_name
                result_dict[user_id][device_id] = r

        defer.returnValue(result_dict)

    @defer.inlineCallbacks
    def on_federation_query_client_keys(self, query_body):
        """ Handle a device key query from a federated server
        """
        device_keys_query = query_body.get("device_keys", {})
        res = yield self.query_local_devices(device_keys_query)
        defer.returnValue({"device_keys": res})

    @defer.inlineCallbacks
    def claim_one_time_keys(self, query, timeout):
        local_query = []
        remote_queries = {}

        for user_id, device_keys in query.get("one_time_keys", {}).items():
            # we use UserID.from_string to catch invalid user ids
            if self.is_mine(UserID.from_string(user_id)):
                for device_id, algorithm in device_keys.items():
                    local_query.append((user_id, device_id, algorithm))
            else:
                domain = get_domain_from_id(user_id)
                remote_queries.setdefault(domain, {})[user_id] = device_keys

        results = yield self.store.claim_e2e_one_time_keys(local_query)

        json_result = {}
        failures = {}
        for user_id, device_keys in results.items():
            for device_id, keys in device_keys.items():
                for key_id, json_bytes in keys.items():
                    json_result.setdefault(user_id, {})[device_id] = {
                        key_id: json.loads(json_bytes)
                    }

        @defer.inlineCallbacks
        def claim_client_keys(destination):
            device_keys = remote_queries[destination]
            try:
                remote_result = yield self.federation.claim_client_keys(
                    destination,
                    {"one_time_keys": device_keys},
                    timeout=timeout
                )
                for user_id, keys in remote_result["one_time_keys"].items():
                    if user_id in device_keys:
                        json_result[user_id] = keys
            except Exception as e:
                failures[destination] = _exception_to_failure(e)

        yield make_deferred_yieldable(defer.gatherResults([
            run_in_background(claim_client_keys, destination)
            for destination in remote_queries
        ], consumeErrors=True))

        logger.info(
            "Claimed one-time-keys: %s",
            ",".join((
                "%s for %s:%s" % (key_id, user_id, device_id)
                for user_id, user_keys in iteritems(json_result)
                for device_id, device_keys in iteritems(user_keys)
                for key_id, _ in iteritems(device_keys)
            )),
        )

        defer.returnValue({
            "one_time_keys": json_result,
            "failures": failures
        })

    @defer.inlineCallbacks
    def upload_keys_for_user(self, user_id, device_id, keys):
        time_now = self.clock.time_msec()

        # TODO: Validate the JSON to make sure it has the right keys.
        device_keys = keys.get("device_keys", None)
        if device_keys:
            logger.info(
                "Updating device_keys for device %r for user %s at %d",
                device_id, user_id, time_now
            )
            # TODO: Sign the JSON with the server key
            changed = yield self.store.set_e2e_device_keys(
                user_id, device_id, time_now, device_keys,
            )
            if changed:
                # Only notify about device updates *if* the keys actually changed
                yield self.device_handler.notify_device_update(user_id, [device_id])

        one_time_keys = keys.get("one_time_keys", None)
        if one_time_keys:
            yield self._upload_one_time_keys_for_user(
                user_id, device_id, time_now, one_time_keys,
            )

        # the device should have been registered already, but it may have been
        # deleted due to a race with a DELETE request. Or we may be using an
        # old access_token without an associated device_id. Either way, we
        # need to double-check the device is registered to avoid ending up with
        # keys without a corresponding device.
        yield self.device_handler.check_device_registered(user_id, device_id)

        result = yield self.store.count_e2e_one_time_keys(user_id, device_id)

        defer.returnValue({"one_time_key_counts": result})

    @defer.inlineCallbacks
    def _upload_one_time_keys_for_user(self, user_id, device_id, time_now,
                                       one_time_keys):
        logger.info(
            "Adding one_time_keys %r for device %r for user %r at %d",
            one_time_keys.keys(), device_id, user_id, time_now,
        )

        # make a list of (alg, id, key) tuples
        key_list = []
        for key_id, key_obj in one_time_keys.items():
            algorithm, key_id = key_id.split(":")
            key_list.append((
                algorithm, key_id, key_obj
            ))

        # First we check if we have already persisted any of the keys.
        existing_key_map = yield self.store.get_e2e_one_time_keys(
            user_id, device_id, [k_id for _, k_id, _ in key_list]
        )

        new_keys = []  # Keys that we need to insert. (alg, id, json) tuples.
        for algorithm, key_id, key in key_list:
            ex_json = existing_key_map.get((algorithm, key_id), None)
            if ex_json:
                if not _one_time_keys_match(ex_json, key):
                    raise SynapseError(
                        400,
                        ("One time key %s:%s already exists. "
                         "Old key: %s; new key: %r") %
                        (algorithm, key_id, ex_json, key)
                    )
            else:
                new_keys.append((
                    algorithm, key_id, encode_canonical_json(key).decode('ascii')))

        yield self.store.add_e2e_one_time_keys(
            user_id, device_id, time_now, new_keys
        )


def _exception_to_failure(e):
    if isinstance(e, CodeMessageException):
        return {
            "status": e.code, "message": str(e),
        }

    if isinstance(e, NotRetryingDestination):
        return {
            "status": 503, "message": "Not ready for retry",
        }

    if isinstance(e, FederationDeniedError):
        return {
            "status": 403, "message": "Federation Denied",
        }

    # include ConnectionRefused and other errors
    #
    # Note that some Exceptions (notably twisted's ResponseFailed etc) don't
    # give a string for e.message, which json then fails to serialize.
    return {
        "status": 503, "message": str(e),
    }


def _one_time_keys_match(old_key_json, new_key):
    old_key = json.loads(old_key_json)

    # if either is a string rather than an object, they must match exactly
    if not isinstance(old_key, dict) or not isinstance(new_key, dict):
        return old_key == new_key

    # otherwise, we strip off the 'signatures' if any, because it's legitimate
    # for different upload attempts to have different signatures.
    old_key.pop("signatures", None)
    new_key_copy = dict(new_key)
    new_key_copy.pop("signatures", None)

    return old_key == new_key_copy