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