Line data Source code
1 : /*
2 : * Famedly Matrix SDK
3 : * Copyright (C) 2019, 2020, 2021 Famedly GmbH
4 : *
5 : * This program is free software: you can redistribute it and/or modify
6 : * it under the terms of the GNU Affero General Public License as
7 : * published by the Free Software Foundation, either version 3 of the
8 : * License, or (at your option) any later version.
9 : *
10 : * This program is distributed in the hope that it will be useful,
11 : * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 : * GNU Affero General Public License for more details.
14 : *
15 : * You should have received a copy of the GNU Affero General Public License
16 : * along with this program. If not, see <https://www.gnu.org/licenses/>.
17 : */
18 :
19 : import 'dart:async';
20 : import 'dart:convert';
21 :
22 : import 'package:olm/olm.dart' as olm;
23 :
24 : import 'package:matrix/encryption/cross_signing.dart';
25 : import 'package:matrix/encryption/key_manager.dart';
26 : import 'package:matrix/encryption/key_verification_manager.dart';
27 : import 'package:matrix/encryption/olm_manager.dart';
28 : import 'package:matrix/encryption/ssss.dart';
29 : import 'package:matrix/encryption/utils/bootstrap.dart';
30 : import 'package:matrix/matrix.dart';
31 : import 'package:matrix/src/utils/copy_map.dart';
32 : import 'package:matrix/src/utils/run_in_root.dart';
33 :
34 : class Encryption {
35 : final Client client;
36 : final bool debug;
37 :
38 75 : bool get enabled => olmManager.enabled;
39 :
40 : /// Returns the base64 encoded keys to store them in a store.
41 : /// This String should **never** leave the device!
42 72 : String? get pickledOlmAccount => olmManager.pickledOlmAccount;
43 :
44 72 : String? get fingerprintKey => olmManager.fingerprintKey;
45 27 : String? get identityKey => olmManager.identityKey;
46 :
47 : /// Returns the database used to store olm sessions and the olm account.
48 : /// We don't want to store olm keys for dehydrated devices.
49 25 : DatabaseApi? get olmDatabase =>
50 150 : ourDeviceId == client.deviceID ? client.database : null;
51 :
52 : late final KeyManager keyManager;
53 : late final OlmManager olmManager;
54 : late final KeyVerificationManager keyVerificationManager;
55 : late final CrossSigning crossSigning;
56 : late SSSS ssss; // some tests mock this, which is why it isn't final
57 :
58 : late String ourDeviceId;
59 :
60 25 : Encryption({
61 : required this.client,
62 : this.debug = false,
63 : }) {
64 50 : ssss = SSSS(this);
65 50 : keyManager = KeyManager(this);
66 50 : olmManager = OlmManager(this);
67 50 : keyVerificationManager = KeyVerificationManager(this);
68 50 : crossSigning = CrossSigning(this);
69 : }
70 :
71 : // initial login passes null to init a new olm account
72 25 : Future<void> init(
73 : String? olmAccount, {
74 : String? deviceId,
75 : String? pickleKey,
76 : String? dehydratedDeviceAlgorithm,
77 : }) async {
78 75 : ourDeviceId = deviceId ?? client.deviceID!;
79 : final isDehydratedDevice = dehydratedDeviceAlgorithm != null;
80 50 : await olmManager.init(
81 : olmAccount: olmAccount,
82 25 : deviceId: isDehydratedDevice ? deviceId : ourDeviceId,
83 : pickleKey: pickleKey,
84 : dehydratedDeviceAlgorithm: dehydratedDeviceAlgorithm,
85 : );
86 :
87 50 : if (!isDehydratedDevice) keyManager.startAutoUploadKeys();
88 : }
89 :
90 25 : bool isMinOlmVersion(int major, int minor, int patch) {
91 : try {
92 25 : final version = olm.get_library_version();
93 50 : return version[0] > major ||
94 50 : (version[0] == major &&
95 50 : (version[1] > minor ||
96 100 : (version[1] == minor && version[2] >= patch)));
97 : } catch (_) {
98 : return false;
99 : }
100 : }
101 :
102 2 : Bootstrap bootstrap({void Function(Bootstrap)? onUpdate}) => Bootstrap(
103 : encryption: this,
104 : onUpdate: onUpdate,
105 : );
106 :
107 25 : void handleDeviceOneTimeKeysCount(
108 : Map<String, int>? countJson,
109 : List<String>? unusedFallbackKeyTypes,
110 : ) {
111 25 : runInRoot(
112 75 : () async => olmManager.handleDeviceOneTimeKeysCount(
113 : countJson,
114 : unusedFallbackKeyTypes,
115 : ),
116 : );
117 : }
118 :
119 25 : void onSync() {
120 : // ignore: discarded_futures
121 50 : keyVerificationManager.cleanup();
122 : }
123 :
124 25 : Future<void> handleToDeviceEvent(ToDeviceEvent event) async {
125 50 : if (event.type == EventTypes.RoomKey) {
126 : // a new room key. We need to handle this asap, before other
127 : // events in /sync are handled
128 48 : await keyManager.handleToDeviceEvent(event);
129 : }
130 25 : if ([EventTypes.RoomKeyRequest, EventTypes.ForwardedRoomKey]
131 50 : .contains(event.type)) {
132 : // "just" room key request things. We don't need these asap, so we handle
133 : // them in the background
134 0 : runInRoot(() => keyManager.handleToDeviceEvent(event));
135 : }
136 50 : if (event.type == EventTypes.Dummy) {
137 : // the previous device just had to create a new olm session, due to olm session
138 : // corruption. We want to try to send it the last message we just sent it, if possible
139 0 : runInRoot(() => olmManager.handleToDeviceEvent(event));
140 : }
141 50 : if (event.type.startsWith('m.key.verification.')) {
142 : // some key verification event. No need to handle it now, we can easily
143 : // do this in the background
144 :
145 0 : runInRoot(() => keyVerificationManager.handleToDeviceEvent(event));
146 : }
147 50 : if (event.type.startsWith('m.secret.')) {
148 : // some ssss thing. We can do this in the background
149 0 : runInRoot(() => ssss.handleToDeviceEvent(event));
150 : }
151 100 : if (event.sender == client.userID) {
152 : // maybe we need to re-try SSSS secrets
153 8 : runInRoot(() => ssss.periodicallyRequestMissingCache());
154 : }
155 : }
156 :
157 25 : Future<void> handleEventUpdate(EventUpdate update) async {
158 50 : if (update.type == EventUpdateType.history) {
159 : return;
160 : }
161 75 : if (update.content['type'].startsWith('m.key.verification.') ||
162 75 : (update.content['type'] == EventTypes.Message &&
163 100 : (update.content['content']['msgtype'] is String) &&
164 75 : update.content['content']['msgtype']
165 25 : .startsWith('m.key.verification.'))) {
166 : // "just" key verification, no need to do this in sync
167 8 : runInRoot(() => keyVerificationManager.handleEventUpdate(update));
168 : }
169 125 : if (update.content['sender'] == client.userID &&
170 59 : update.content['unsigned']?['transaction_id'] == null) {
171 : // maybe we need to re-try SSSS secrets
172 100 : runInRoot(() => ssss.periodicallyRequestMissingCache());
173 : }
174 : }
175 :
176 25 : Future<ToDeviceEvent> decryptToDeviceEvent(ToDeviceEvent event) async {
177 : try {
178 50 : return await olmManager.decryptToDeviceEvent(event);
179 : } catch (e, s) {
180 12 : Logs().w(
181 18 : '[LibOlm] Could not decrypt to device event from ${event.sender} with content: ${event.content}',
182 : e,
183 : s,
184 : );
185 18 : client.onEncryptionError.add(
186 6 : SdkError(
187 6 : exception: e is Exception ? e : Exception(e),
188 : stackTrace: s,
189 : ),
190 : );
191 : return event;
192 : }
193 : }
194 :
195 6 : Event decryptRoomEventSync(Event event) {
196 18 : if (event.type != EventTypes.Encrypted || event.redacted) {
197 : return event;
198 : }
199 6 : final content = event.parsedRoomEncryptedContent;
200 12 : if (event.type != EventTypes.Encrypted ||
201 6 : content.ciphertextMegolm == null) {
202 : return event;
203 : }
204 : Map<String, dynamic> decryptedPayload;
205 : var canRequestSession = false;
206 : try {
207 10 : if (content.algorithm != AlgorithmTypes.megolmV1AesSha2) {
208 0 : throw DecryptException(DecryptException.unknownAlgorithm);
209 : }
210 5 : final sessionId = content.sessionId;
211 : if (sessionId == null) {
212 0 : throw DecryptException(DecryptException.unknownSession);
213 : }
214 :
215 : final inboundGroupSession =
216 20 : keyManager.getInboundGroupSession(event.room.id, sessionId);
217 3 : if (!(inboundGroupSession?.isValid ?? false)) {
218 : canRequestSession = true;
219 3 : throw DecryptException(DecryptException.unknownSession);
220 : }
221 :
222 : // decrypt errors here may mean we have a bad session key - others might have a better one
223 : canRequestSession = true;
224 :
225 3 : final decryptResult = inboundGroupSession!.inboundGroupSession!
226 6 : .decrypt(content.ciphertextMegolm!);
227 : canRequestSession = false;
228 :
229 : // we can't have the key be an int, else json-serializing will fail, thus we need it to be a string
230 6 : final messageIndexKey = 'key-${decryptResult.message_index}';
231 : final messageIndexValue =
232 12 : '${event.eventId}|${event.originServerTs.millisecondsSinceEpoch}';
233 : final haveIndex =
234 6 : inboundGroupSession.indexes.containsKey(messageIndexKey);
235 : if (haveIndex &&
236 3 : inboundGroupSession.indexes[messageIndexKey] != messageIndexValue) {
237 0 : Logs().e('[Decrypt] Could not decrypt due to a corrupted session.');
238 0 : throw DecryptException(DecryptException.channelCorrupted);
239 : }
240 :
241 6 : inboundGroupSession.indexes[messageIndexKey] = messageIndexValue;
242 : if (!haveIndex) {
243 : // now we persist the udpated indexes into the database.
244 : // the entry should always exist. In the case it doesn't, the following
245 : // line *could* throw an error. As that is a future, though, and we call
246 : // it un-awaited here, nothing happens, which is exactly the result we want
247 6 : client.database
248 : // ignore: discarded_futures
249 3 : ?.updateInboundGroupSessionIndexes(
250 6 : json.encode(inboundGroupSession.indexes),
251 6 : event.room.id,
252 : sessionId,
253 : )
254 : // ignore: discarded_futures
255 3 : .onError((e, _) => Logs().e('Ignoring error for updating indexes'));
256 : }
257 6 : decryptedPayload = json.decode(decryptResult.plaintext);
258 : } catch (exception) {
259 : // alright, if this was actually by our own outbound group session, we might as well clear it
260 6 : if (exception.toString() != DecryptException.unknownSession &&
261 1 : (keyManager
262 3 : .getOutboundGroupSession(event.room.id)
263 0 : ?.outboundGroupSession
264 0 : ?.session_id() ??
265 1 : '') ==
266 1 : content.sessionId) {
267 0 : runInRoot(
268 0 : () async => keyManager.clearOrUseOutboundGroupSession(
269 0 : event.room.id,
270 : wipe: true,
271 : ),
272 : );
273 : }
274 : if (canRequestSession) {
275 3 : decryptedPayload = {
276 3 : 'content': event.content,
277 : 'type': EventTypes.Encrypted,
278 : };
279 9 : decryptedPayload['content']['body'] = exception.toString();
280 6 : decryptedPayload['content']['msgtype'] = MessageTypes.BadEncrypted;
281 6 : decryptedPayload['content']['can_request_session'] = true;
282 : } else {
283 0 : decryptedPayload = {
284 0 : 'content': <String, dynamic>{
285 : 'msgtype': MessageTypes.BadEncrypted,
286 0 : 'body': exception.toString(),
287 : },
288 : 'type': EventTypes.Encrypted,
289 : };
290 : }
291 : }
292 10 : if (event.content['m.relates_to'] != null) {
293 0 : decryptedPayload['content']['m.relates_to'] =
294 0 : event.content['m.relates_to'];
295 : }
296 5 : return Event(
297 5 : content: decryptedPayload['content'],
298 5 : type: decryptedPayload['type'],
299 5 : senderId: event.senderId,
300 5 : eventId: event.eventId,
301 5 : room: event.room,
302 5 : originServerTs: event.originServerTs,
303 5 : unsigned: event.unsigned,
304 5 : stateKey: event.stateKey,
305 5 : prevContent: event.prevContent,
306 5 : status: event.status,
307 : originalSource: event,
308 : );
309 : }
310 :
311 5 : Future<Event> decryptRoomEvent(
312 : Event event, {
313 : bool store = false,
314 : EventUpdateType updateType = EventUpdateType.timeline,
315 : }) async {
316 : try {
317 15 : if (event.type != EventTypes.Encrypted || event.redacted) {
318 : return event;
319 : }
320 5 : final content = event.parsedRoomEncryptedContent;
321 5 : final sessionId = content.sessionId;
322 10 : if (client.database != null &&
323 : sessionId != null &&
324 4 : !(keyManager
325 4 : .getInboundGroupSession(
326 8 : event.room.id,
327 : sessionId,
328 : )
329 1 : ?.isValid ??
330 : false)) {
331 8 : await keyManager.loadInboundGroupSession(
332 8 : event.room.id,
333 : sessionId,
334 : );
335 : }
336 5 : event = decryptRoomEventSync(event);
337 10 : if (event.type == EventTypes.Encrypted &&
338 12 : event.content['can_request_session'] == true &&
339 : sessionId != null) {
340 6 : keyManager.maybeAutoRequest(
341 6 : event.room.id,
342 : sessionId,
343 3 : content.senderKey,
344 : );
345 : }
346 10 : if (event.type != EventTypes.Encrypted && store) {
347 1 : if (updateType != EventUpdateType.history) {
348 2 : event.room.setState(event);
349 : }
350 0 : await client.database?.storeEventUpdate(
351 0 : EventUpdate(
352 0 : content: event.toJson(),
353 0 : roomID: event.room.id,
354 : type: updateType,
355 : ),
356 0 : client,
357 : );
358 : }
359 : return event;
360 : } catch (e, s) {
361 2 : Logs().e('[Decrypt] Could not decrpyt event', e, s);
362 : return event;
363 : }
364 : }
365 :
366 : /// Encrypts the given json payload and creates a send-ready m.room.encrypted
367 : /// payload. This will create a new outgoingGroupSession if necessary.
368 3 : Future<Map<String, dynamic>> encryptGroupMessagePayload(
369 : String roomId,
370 : Map<String, dynamic> payload, {
371 : String type = EventTypes.Message,
372 : }) async {
373 3 : payload = copyMap(payload);
374 3 : final Map<String, dynamic>? mRelatesTo = payload.remove('m.relates_to');
375 :
376 : // Events which only contain a m.relates_to like reactions don't need to
377 : // be encrypted.
378 3 : if (payload.isEmpty && mRelatesTo != null) {
379 0 : return {'m.relates_to': mRelatesTo};
380 : }
381 6 : final room = client.getRoomById(roomId);
382 6 : if (room == null || !room.encrypted || !enabled) {
383 : return payload;
384 : }
385 6 : if (room.encryptionAlgorithm != AlgorithmTypes.megolmV1AesSha2) {
386 : throw ('Unknown encryption algorithm');
387 : }
388 11 : if (keyManager.getOutboundGroupSession(roomId)?.isValid != true) {
389 4 : await keyManager.loadOutboundGroupSession(roomId);
390 : }
391 6 : await keyManager.clearOrUseOutboundGroupSession(roomId);
392 11 : if (keyManager.getOutboundGroupSession(roomId)?.isValid != true) {
393 4 : await keyManager.createOutboundGroupSession(roomId);
394 : }
395 6 : final sess = keyManager.getOutboundGroupSession(roomId);
396 6 : if (sess?.isValid != true) {
397 : throw ('Unable to create new outbound group session');
398 : }
399 : // we clone the payload as we do not want to remove 'm.relates_to' from the
400 : // original payload passed into this function
401 3 : payload = payload.copy();
402 3 : final payloadContent = {
403 : 'content': payload,
404 : 'type': type,
405 : 'room_id': roomId,
406 : };
407 3 : final encryptedPayload = <String, dynamic>{
408 3 : 'algorithm': AlgorithmTypes.megolmV1AesSha2,
409 3 : 'ciphertext':
410 9 : sess!.outboundGroupSession!.encrypt(json.encode(payloadContent)),
411 : // device_id + sender_key should be removed at some point in future since
412 : // they're deprecated. Just left here for compatibility
413 9 : 'device_id': client.deviceID,
414 6 : 'sender_key': identityKey,
415 9 : 'session_id': sess.outboundGroupSession!.session_id(),
416 0 : if (mRelatesTo != null) 'm.relates_to': mRelatesTo,
417 : };
418 6 : await keyManager.storeOutboundGroupSession(roomId, sess);
419 : return encryptedPayload;
420 : }
421 :
422 10 : Future<Map<String, Map<String, Map<String, dynamic>>>> encryptToDeviceMessage(
423 : List<DeviceKeys> deviceKeys,
424 : String type,
425 : Map<String, dynamic> payload,
426 : ) async {
427 20 : return await olmManager.encryptToDeviceMessage(deviceKeys, type, payload);
428 : }
429 :
430 0 : Future<void> autovalidateMasterOwnKey() async {
431 : // check if we can set our own master key as verified, if it isn't yet
432 0 : final userId = client.userID;
433 0 : final masterKey = client.userDeviceKeys[userId]?.masterKey;
434 0 : if (client.database != null &&
435 : masterKey != null &&
436 : userId != null &&
437 0 : !masterKey.directVerified &&
438 0 : masterKey.hasValidSignatureChain(onlyValidateUserIds: {userId})) {
439 0 : await masterKey.setVerified(true);
440 : }
441 : }
442 :
443 22 : Future<void> dispose() async {
444 44 : keyManager.dispose();
445 44 : await olmManager.dispose();
446 44 : keyVerificationManager.dispose();
447 : }
448 : }
449 :
450 : class DecryptException implements Exception {
451 : String cause;
452 : String? libolmMessage;
453 9 : DecryptException(this.cause, [this.libolmMessage]);
454 :
455 7 : @override
456 : String toString() =>
457 23 : cause + (libolmMessage != null ? ': $libolmMessage' : '');
458 :
459 : static const String notEnabled = 'Encryption is not enabled in your client.';
460 : static const String unknownAlgorithm = 'Unknown encryption algorithm.';
461 : static const String unknownSession =
462 : 'The sender has not sent us the session key.';
463 : static const String channelCorrupted =
464 : 'The secure channel with the sender was corrupted.';
465 : static const String unableToDecryptWithAnyOlmSession =
466 : 'Unable to decrypt with any existing OLM session';
467 : static const String senderDoesntMatch =
468 : "Message was decrypted but sender doesn't match";
469 : static const String recipientDoesntMatch =
470 : "Message was decrypted but recipient doesn't match";
471 : static const String ownFingerprintDoesntMatch =
472 : "Message was decrypted but own fingerprint Key doesn't match";
473 : static const String isntSentForThisDevice =
474 : "The message isn't sent for this device";
475 : static const String unknownMessageType = 'Unknown message type';
476 : static const String decryptionFailed = 'Decryption failed';
477 : }
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