famedlysdk/lib/encryption/key_manager.dart

904 lines
32 KiB
Dart

/*
* Famedly Matrix SDK
* Copyright (C) 2019, 2020 Famedly GmbH
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
import 'dart:convert';
import 'package:olm/olm.dart' as olm;
import 'package:pedantic/pedantic.dart';
import './encryption.dart';
import './utils/outbound_group_session.dart';
import './utils/session_key.dart';
import '../famedlysdk.dart';
import '../matrix_api.dart';
import '../src/database/database.dart';
import '../src/utils/logs.dart';
import '../src/utils/run_in_background.dart';
import '../src/utils/run_in_root.dart';
const MEGOLM_KEY = 'm.megolm_backup.v1';
class KeyManager {
final Encryption encryption;
Client get client => encryption.client;
final outgoingShareRequests = <String, KeyManagerKeyShareRequest>{};
final incomingShareRequests = <String, KeyManagerKeyShareRequest>{};
final _inboundGroupSessions = <String, Map<String, SessionKey>>{};
final _outboundGroupSessions = <String, OutboundGroupSession>{};
final Set<String> _loadedOutboundGroupSessions = <String>{};
final Set<String> _requestedSessionIds = <String>{};
KeyManager(this.encryption) {
encryption.ssss.setValidator(MEGOLM_KEY, (String secret) async {
final keyObj = olm.PkDecryption();
try {
final info = await getRoomKeysBackupInfo(false);
if (info.algorithm != RoomKeysAlgorithmType.v1Curve25519AesSha2) {
return false;
}
if (keyObj.init_with_private_key(base64.decode(secret)) ==
info.authData['public_key']) {
_requestedSessionIds.clear();
return true;
}
return false;
} catch (_) {
return false;
} finally {
keyObj.free();
}
});
}
bool get enabled => client.accountData[MEGOLM_KEY] != null;
/// clear all cached inbound group sessions. useful for testing
void clearInboundGroupSessions() {
_inboundGroupSessions.clear();
}
void setInboundGroupSession(String roomId, String sessionId, String senderKey,
Map<String, dynamic> content,
{bool forwarded = false,
Map<String, String> senderClaimedKeys,
bool uploaded = false}) {
senderClaimedKeys ??= <String, String>{};
if (!senderClaimedKeys.containsKey('ed25519')) {
final device = client.getUserDeviceKeysByCurve25519Key(senderKey);
if (device != null) {
senderClaimedKeys['ed25519'] = device.ed25519Key;
}
}
final oldSession =
getInboundGroupSession(roomId, sessionId, senderKey, otherRooms: false);
if (content['algorithm'] != 'm.megolm.v1.aes-sha2') {
return;
}
olm.InboundGroupSession inboundGroupSession;
try {
inboundGroupSession = olm.InboundGroupSession();
if (forwarded) {
inboundGroupSession.import_session(content['session_key']);
} else {
inboundGroupSession.create(content['session_key']);
}
} catch (e, s) {
inboundGroupSession.free();
Logs.error(
'[LibOlm] Could not create new InboundGroupSession: ' + e.toString(),
s);
return;
}
final newSession = SessionKey(
content: content,
inboundGroupSession: inboundGroupSession,
indexes: {},
roomId: roomId,
sessionId: sessionId,
key: client.userID,
senderKey: senderKey,
senderClaimedKeys: senderClaimedKeys,
);
final oldFirstIndex =
oldSession?.inboundGroupSession?.first_known_index() ?? 0;
final newFirstIndex = newSession.inboundGroupSession.first_known_index();
if (oldSession == null ||
newFirstIndex < oldFirstIndex ||
(oldFirstIndex == newFirstIndex &&
newSession.forwardingCurve25519KeyChain.length <
oldSession.forwardingCurve25519KeyChain.length)) {
// use new session
oldSession?.dispose();
} else {
// we are gonna keep our old session
newSession.dispose();
return;
}
if (!_inboundGroupSessions.containsKey(roomId)) {
_inboundGroupSessions[roomId] = <String, SessionKey>{};
}
_inboundGroupSessions[roomId][sessionId] = newSession;
client.database
?.storeInboundGroupSession(
client.id,
roomId,
sessionId,
inboundGroupSession.pickle(client.userID),
json.encode(content),
json.encode({}),
senderKey,
json.encode(senderClaimedKeys),
)
?.then((_) {
if (uploaded) {
client.database
.markInboundGroupSessionAsUploaded(client.id, roomId, sessionId);
}
});
// TODO: somehow try to decrypt last message again
final room = client.getRoomById(roomId);
if (room != null) {
room.onSessionKeyReceived.add(sessionId);
}
}
SessionKey getInboundGroupSession(
String roomId, String sessionId, String senderKey,
{bool otherRooms = true}) {
if (_inboundGroupSessions.containsKey(roomId) &&
_inboundGroupSessions[roomId].containsKey(sessionId)) {
final sess = _inboundGroupSessions[roomId][sessionId];
if (sess.senderKey != senderKey && sess.senderKey.isNotEmpty) {
return null;
}
return sess;
}
if (!otherRooms) {
return null;
}
// search if this session id is *somehow* found in another room
for (final val in _inboundGroupSessions.values) {
if (val.containsKey(sessionId)) {
final sess = val[sessionId];
if (sess.senderKey != senderKey && sess.senderKey.isNotEmpty) {
return null;
}
return sess;
}
}
return null;
}
/// Loads an inbound group session
Future<SessionKey> loadInboundGroupSession(
String roomId, String sessionId, String senderKey) async {
if (roomId == null || sessionId == null || senderKey == null) {
return null;
}
if (_inboundGroupSessions.containsKey(roomId) &&
_inboundGroupSessions[roomId].containsKey(sessionId)) {
final sess = _inboundGroupSessions[roomId][sessionId];
if (sess.senderKey != senderKey && sess.senderKey.isNotEmpty) {
return null; // sender keys do not match....better not do anything
}
return sess; // nothing to do
}
final session = await client.database
?.getDbInboundGroupSession(client.id, roomId, sessionId);
if (session == null) {
final room = client.getRoomById(roomId);
final requestIdent = '$roomId|$sessionId|$senderKey';
if (client.enableE2eeRecovery &&
room != null &&
!_requestedSessionIds.contains(requestIdent) &&
!client.isUnknownSession) {
// do e2ee recovery
_requestedSessionIds.add(requestIdent);
unawaited(runInRoot(() =>
request(room, sessionId, senderKey, askOnlyOwnDevices: true)));
}
return null;
}
if (!_inboundGroupSessions.containsKey(roomId)) {
_inboundGroupSessions[roomId] = <String, SessionKey>{};
}
final sess = SessionKey.fromDb(session, client.userID);
if (!sess.isValid ||
(sess.senderKey.isNotEmpty && sess.senderKey != senderKey)) {
return null;
}
_inboundGroupSessions[roomId][sessionId] = sess;
return sess;
}
/// clear all cached inbound group sessions. useful for testing
void clearOutboundGroupSessions() {
_outboundGroupSessions.clear();
}
/// Clears the existing outboundGroupSession but first checks if the participating
/// devices have been changed. Returns false if the session has not been cleared because
/// it wasn't necessary.
Future<bool> clearOutboundGroupSession(String roomId,
{bool wipe = false}) async {
final room = client.getRoomById(roomId);
final sess = getOutboundGroupSession(roomId);
if (room == null || sess == null) {
return true;
}
if (!wipe) {
// first check if the devices in the room changed
final deviceKeys = await room.getUserDeviceKeys();
deviceKeys.removeWhere((k) => k.blocked);
final deviceKeyIds = deviceKeys.map((k) => k.deviceId).toList();
deviceKeyIds.sort();
if (deviceKeyIds.toString() != sess.devices.toString()) {
wipe = true;
}
// next check if it needs to be rotated
final encryptionContent = room.getState(EventTypes.Encryption)?.content;
final maxMessages = encryptionContent != null &&
encryptionContent['rotation_period_msgs'] is int
? encryptionContent['rotation_period_msgs']
: 100;
final maxAge = encryptionContent != null &&
encryptionContent['rotation_period_ms'] is int
? encryptionContent['rotation_period_ms']
: 604800000; // default of one week
if (sess.sentMessages >= maxMessages ||
sess.creationTime
.add(Duration(milliseconds: maxAge))
.isBefore(DateTime.now())) {
wipe = true;
}
if (!wipe) {
return false;
}
}
sess.dispose();
_outboundGroupSessions.remove(roomId);
await client.database?.removeOutboundGroupSession(client.id, roomId);
return true;
}
Future<void> storeOutboundGroupSession(
String roomId, OutboundGroupSession sess) async {
if (sess == null) {
return;
}
await client.database?.storeOutboundGroupSession(
client.id,
roomId,
sess.outboundGroupSession.pickle(client.userID),
json.encode(sess.devices),
sess.creationTime.millisecondsSinceEpoch,
sess.sentMessages);
}
Future<OutboundGroupSession> createOutboundGroupSession(String roomId) async {
await clearOutboundGroupSession(roomId, wipe: true);
final room = client.getRoomById(roomId);
if (room == null) {
return null;
}
final deviceKeys = await room.getUserDeviceKeys();
deviceKeys.removeWhere((k) => k.blocked);
final deviceKeyIds = deviceKeys.map((k) => k.deviceId).toList();
deviceKeyIds.sort();
final outboundGroupSession = olm.OutboundGroupSession();
try {
outboundGroupSession.create();
} catch (e, s) {
outboundGroupSession.free();
Logs.error(
'[LibOlm] Unable to create new outboundGroupSession: ' + e.toString(),
s);
return null;
}
final rawSession = <String, dynamic>{
'algorithm': 'm.megolm.v1.aes-sha2',
'room_id': room.id,
'session_id': outboundGroupSession.session_id(),
'session_key': outboundGroupSession.session_key(),
};
setInboundGroupSession(
roomId, rawSession['session_id'], encryption.identityKey, rawSession);
final sess = OutboundGroupSession(
devices: deviceKeyIds,
creationTime: DateTime.now(),
outboundGroupSession: outboundGroupSession,
sentMessages: 0,
key: client.userID,
);
try {
await client.sendToDeviceEncrypted(deviceKeys, 'm.room_key', rawSession);
await storeOutboundGroupSession(roomId, sess);
_outboundGroupSessions[roomId] = sess;
} catch (e, s) {
Logs.error(
'[LibOlm] Unable to send the session key to the participating devices: ' +
e.toString(),
s);
sess.dispose();
return null;
}
return sess;
}
OutboundGroupSession getOutboundGroupSession(String roomId) {
return _outboundGroupSessions[roomId];
}
Future<void> loadOutboundGroupSession(String roomId) async {
if (_loadedOutboundGroupSessions.contains(roomId) ||
_outboundGroupSessions.containsKey(roomId) ||
client.database == null) {
return; // nothing to do
}
_loadedOutboundGroupSessions.add(roomId);
final session =
await client.database.getDbOutboundGroupSession(client.id, roomId);
if (session == null) {
return;
}
final sess = OutboundGroupSession.fromDb(session, client.userID);
if (!sess.isValid) {
return;
}
_outboundGroupSessions[roomId] = sess;
}
Future<bool> isCached() async {
if (!enabled) {
return false;
}
return (await encryption.ssss.getCached(MEGOLM_KEY)) != null;
}
RoomKeysVersionResponse _roomKeysVersionCache;
DateTime _roomKeysVersionCacheDate;
Future<RoomKeysVersionResponse> getRoomKeysBackupInfo(
[bool useCache = true]) async {
if (_roomKeysVersionCache != null &&
_roomKeysVersionCacheDate != null &&
useCache &&
DateTime.now()
.subtract(Duration(minutes: 5))
.isBefore(_roomKeysVersionCacheDate)) {
return _roomKeysVersionCache;
}
_roomKeysVersionCache = await client.getRoomKeysBackup();
_roomKeysVersionCacheDate = DateTime.now();
return _roomKeysVersionCache;
}
Future<void> loadFromResponse(RoomKeys keys) async {
if (!(await isCached())) {
return;
}
final privateKey =
base64.decode(await encryption.ssss.getCached(MEGOLM_KEY));
final decryption = olm.PkDecryption();
final info = await getRoomKeysBackupInfo();
String backupPubKey;
try {
backupPubKey = decryption.init_with_private_key(privateKey);
if (backupPubKey == null ||
info.algorithm != RoomKeysAlgorithmType.v1Curve25519AesSha2 ||
info.authData['public_key'] != backupPubKey) {
return;
}
for (final roomEntry in keys.rooms.entries) {
final roomId = roomEntry.key;
for (final sessionEntry in roomEntry.value.sessions.entries) {
final sessionId = sessionEntry.key;
final session = sessionEntry.value;
final firstMessageIndex = session.firstMessageIndex;
final forwardedCount = session.forwardedCount;
final isVerified = session.isVerified;
final sessionData = session.sessionData;
if (firstMessageIndex == null ||
forwardedCount == null ||
isVerified == null ||
!(sessionData is Map)) {
continue;
}
Map<String, dynamic> decrypted;
try {
decrypted = json.decode(decryption.decrypt(sessionData['ephemeral'],
sessionData['mac'], sessionData['ciphertext']));
} catch (e, s) {
Logs.error(
'[LibOlm] Error decrypting room key: ' + e.toString(), s);
}
if (decrypted != null) {
decrypted['session_id'] = sessionId;
decrypted['room_id'] = roomId;
setInboundGroupSession(
roomId, sessionId, decrypted['sender_key'], decrypted,
forwarded: true,
senderClaimedKeys: decrypted['sender_claimed_keys'] != null
? Map<String, String>.from(decrypted['sender_claimed_keys'])
: null,
uploaded: true);
}
}
}
} finally {
decryption.free();
}
}
Future<void> loadSingleKey(String roomId, String sessionId) async {
final info = await getRoomKeysBackupInfo();
final ret =
await client.getRoomKeysSingleKey(roomId, sessionId, info.version);
final keys = RoomKeys.fromJson({
'rooms': {
roomId: {
'sessions': {
sessionId: ret.toJson(),
},
},
},
});
await loadFromResponse(keys);
}
/// Request a certain key from another device
Future<void> request(
Room room,
String sessionId,
String senderKey, {
bool tryOnlineBackup = true,
bool askOnlyOwnDevices = false,
}) async {
if (tryOnlineBackup && await isCached()) {
// let's first check our online key backup store thingy...
var hadPreviously =
getInboundGroupSession(room.id, sessionId, senderKey) != null;
try {
await loadSingleKey(room.id, sessionId);
} catch (err, stacktrace) {
if (err is MatrixException && err.errcode == 'M_NOT_FOUND') {
Logs.info(
'[KeyManager] Key not in online key backup, requesting it from other devices...');
} else {
Logs.error(
'[KeyManager] Failed to access online key backup: ' +
err.toString(),
stacktrace);
}
}
if (!hadPreviously &&
getInboundGroupSession(room.id, sessionId, senderKey) != null) {
return; // we managed to load the session from online backup, no need to care about it now
}
}
try {
// while we just send the to-device event to '*', we still need to save the
// devices themself to know where to send the cancel to after receiving a reply
final devices = await room.getUserDeviceKeys();
if (askOnlyOwnDevices) {
devices.removeWhere((d) => d.userId != client.userID);
}
final requestId = client.generateUniqueTransactionId();
final request = KeyManagerKeyShareRequest(
requestId: requestId,
devices: devices,
room: room,
sessionId: sessionId,
senderKey: senderKey,
);
final userList = await room.requestParticipants();
await client.sendToDevicesOfUserIds(
userList.map<String>((u) => u.id).toSet(),
'm.room_key_request',
{
'action': 'request',
'body': {
'algorithm': 'm.megolm.v1.aes-sha2',
'room_id': room.id,
'sender_key': senderKey,
'session_id': sessionId,
},
'request_id': requestId,
'requesting_device_id': client.deviceID,
},
);
outgoingShareRequests[request.requestId] = request;
} catch (e, s) {
Logs.error(
'[Key Manager] Sending key verification request failed: ' +
e.toString(),
s);
}
}
bool _isUploadingKeys = false;
Future<void> backgroundTasks() async {
if (_isUploadingKeys || client.database == null) {
return;
}
_isUploadingKeys = true;
try {
if (!(await isCached())) {
return; // we can't backup anyways
}
final dbSessions =
await client.database.getInboundGroupSessionsToUpload().get();
if (dbSessions.isEmpty) {
return; // nothing to do
}
final privateKey =
base64.decode(await encryption.ssss.getCached(MEGOLM_KEY));
// decryption is needed to calculate the public key and thus see if the claimed information is in fact valid
final decryption = olm.PkDecryption();
final info = await getRoomKeysBackupInfo(false);
String backupPubKey;
try {
backupPubKey = decryption.init_with_private_key(privateKey);
if (backupPubKey == null ||
info.algorithm != RoomKeysAlgorithmType.v1Curve25519AesSha2 ||
info.authData['public_key'] != backupPubKey) {
return;
}
final args = _GenerateUploadKeysArgs(
pubkey: backupPubKey,
dbSessions: <_DbInboundGroupSessionBundle>[],
userId: client.userID,
);
// we need to calculate verified beforehand, as else we pass a closure to an isolate
// with 500 keys they do, however, noticably block the UI, which is why we give brief async suspentions in here
// so that the event loop can progress
var i = 0;
for (final dbSession in dbSessions) {
final device =
client.getUserDeviceKeysByCurve25519Key(dbSession.senderKey);
args.dbSessions.add(_DbInboundGroupSessionBundle(
dbSession: dbSession,
verified: device?.verified ?? false,
));
i++;
if (i > 10) {
await Future.delayed(Duration(milliseconds: 1));
i = 0;
}
}
final roomKeys =
await runInBackground<RoomKeys, _GenerateUploadKeysArgs>(
_generateUploadKeys, args);
Logs.info('[Key Manager] Uploading ${dbSessions.length} room keys...');
// upload the payload...
await client.storeRoomKeys(info.version, roomKeys);
// and now finally mark all the keys as uploaded
// no need to optimze this, as we only run it so seldomly and almost never with many keys at once
for (final dbSession in dbSessions) {
await client.database.markInboundGroupSessionAsUploaded(
client.id, dbSession.roomId, dbSession.sessionId);
}
} finally {
decryption.free();
}
} catch (e, s) {
Logs.error('[Key Manager] Error uploading room keys: ' + e.toString(), s);
} finally {
_isUploadingKeys = false;
}
}
/// Handle an incoming to_device event that is related to key sharing
Future<void> handleToDeviceEvent(ToDeviceEvent event) async {
if (event.type == 'm.room_key_request') {
if (!(event.content['request_id'] is String)) {
return; // invalid event
}
if (event.content['action'] == 'request') {
// we are *receiving* a request
Logs.info('[KeyManager] Received key sharing request...');
if (!event.content.containsKey('body')) {
Logs.info('[KeyManager] No body, doing nothing');
return; // no body
}
if (!client.userDeviceKeys.containsKey(event.sender) ||
!client.userDeviceKeys[event.sender].deviceKeys
.containsKey(event.content['requesting_device_id'])) {
Logs.info('[KeyManager] Device not found, doing nothing');
return; // device not found
}
final device = client.userDeviceKeys[event.sender]
.deviceKeys[event.content['requesting_device_id']];
if (device.userId == client.userID &&
device.deviceId == client.deviceID) {
Logs.info('[KeyManager] Request is by ourself, ignoring');
return; // ignore requests by ourself
}
final room = client.getRoomById(event.content['body']['room_id']);
if (room == null) {
Logs.info('[KeyManager] Unknown room, ignoring');
return; // unknown room
}
final sessionId = event.content['body']['session_id'];
final senderKey = event.content['body']['sender_key'];
// okay, let's see if we have this session at all
if ((await loadInboundGroupSession(room.id, sessionId, senderKey)) ==
null) {
Logs.info('[KeyManager] Unknown session, ignoring');
return; // we don't have this session anyways
}
final request = KeyManagerKeyShareRequest(
requestId: event.content['request_id'],
devices: [device],
room: room,
sessionId: sessionId,
senderKey: senderKey,
);
if (incomingShareRequests.containsKey(request.requestId)) {
Logs.info('[KeyManager] Already processed this request, ignoring');
return; // we don't want to process one and the same request multiple times
}
incomingShareRequests[request.requestId] = request;
final roomKeyRequest =
RoomKeyRequest.fromToDeviceEvent(event, this, request);
if (device.userId == client.userID &&
device.verified &&
!device.blocked) {
Logs.info('[KeyManager] All checks out, forwarding key...');
// alright, we can forward the key
await roomKeyRequest.forwardKey();
} else {
Logs.info(
'[KeyManager] Asking client, if the key should be forwarded');
client.onRoomKeyRequest
.add(roomKeyRequest); // let the client handle this
}
} else if (event.content['action'] == 'request_cancellation') {
// we got told to cancel an incoming request
if (!incomingShareRequests.containsKey(event.content['request_id'])) {
return; // we don't know this request anyways
}
// alright, let's just cancel this request
final request = incomingShareRequests[event.content['request_id']];
request.canceled = true;
incomingShareRequests.remove(request.requestId);
}
} else if (event.type == 'm.forwarded_room_key') {
// we *received* an incoming key request
if (event.encryptedContent == null) {
return; // event wasn't encrypted, this is a security risk
}
final request = outgoingShareRequests.values.firstWhere(
(r) =>
r.room.id == event.content['room_id'] &&
r.sessionId == event.content['session_id'] &&
r.senderKey == event.content['sender_key'],
orElse: () => null);
if (request == null || request.canceled) {
return; // no associated request found or it got canceled
}
final device = request.devices.firstWhere(
(d) =>
d.userId == event.sender &&
d.curve25519Key == event.encryptedContent['sender_key'],
orElse: () => null);
if (device == null) {
return; // someone we didn't send our request to replied....better ignore this
}
// we add the sender key to the forwarded key chain
if (!(event.content['forwarding_curve25519_key_chain'] is List)) {
event.content['forwarding_curve25519_key_chain'] = <String>[];
}
event.content['forwarding_curve25519_key_chain']
.add(event.encryptedContent['sender_key']);
// TODO: verify that the keys work to decrypt a message
// alright, all checks out, let's go ahead and store this session
setInboundGroupSession(
request.room.id, request.sessionId, request.senderKey, event.content,
forwarded: true,
senderClaimedKeys: {
'ed25519': event.content['sender_claimed_ed25519_key'],
});
request.devices.removeWhere(
(k) => k.userId == device.userId && k.deviceId == device.deviceId);
outgoingShareRequests.remove(request.requestId);
// send cancel to all other devices
if (request.devices.isEmpty) {
return; // no need to send any cancellation
}
// Send with send-to-device messaging
final sendToDeviceMessage = {
'action': 'request_cancellation',
'request_id': request.requestId,
'requesting_device_id': client.deviceID,
};
var data = <String, Map<String, Map<String, dynamic>>>{};
for (final device in request.devices) {
if (!data.containsKey(device.userId)) {
data[device.userId] = {};
}
data[device.userId][device.deviceId] = sendToDeviceMessage;
}
await client.sendToDevice(
'm.room_key_request',
client.generateUniqueTransactionId(),
data,
);
} else if (event.type == 'm.room_key') {
if (event.encryptedContent == null) {
return; // the event wasn't encrypted, this is a security risk;
}
final String roomId = event.content['room_id'];
final String sessionId = event.content['session_id'];
if (client.userDeviceKeys.containsKey(event.sender) &&
client.userDeviceKeys[event.sender].deviceKeys
.containsKey(event.content['requesting_device_id'])) {
event.content['sender_claimed_ed25519_key'] = client
.userDeviceKeys[event.sender]
.deviceKeys[event.content['requesting_device_id']]
.ed25519Key;
}
setInboundGroupSession(roomId, sessionId,
event.encryptedContent['sender_key'], event.content,
forwarded: false);
}
}
void dispose() {
for (final sess in _outboundGroupSessions.values) {
sess.dispose();
}
for (final entries in _inboundGroupSessions.values) {
for (final sess in entries.values) {
sess.dispose();
}
}
}
}
class KeyManagerKeyShareRequest {
final String requestId;
final List<DeviceKeys> devices;
final Room room;
final String sessionId;
final String senderKey;
bool canceled;
KeyManagerKeyShareRequest(
{this.requestId,
this.devices,
this.room,
this.sessionId,
this.senderKey,
this.canceled = false});
}
class RoomKeyRequest extends ToDeviceEvent {
KeyManager keyManager;
KeyManagerKeyShareRequest request;
RoomKeyRequest.fromToDeviceEvent(ToDeviceEvent toDeviceEvent,
KeyManager keyManager, KeyManagerKeyShareRequest request) {
this.keyManager = keyManager;
this.request = request;
sender = toDeviceEvent.sender;
content = toDeviceEvent.content;
type = toDeviceEvent.type;
}
Room get room => request.room;
DeviceKeys get requestingDevice => request.devices.first;
Future<void> forwardKey() async {
if (request.canceled) {
keyManager.incomingShareRequests.remove(request.requestId);
return; // request is canceled, don't send anything
}
var room = this.room;
final session = await keyManager.loadInboundGroupSession(
room.id, request.sessionId, request.senderKey);
var message = session.content;
message['forwarding_curve25519_key_chain'] =
List<String>.from(session.forwardingCurve25519KeyChain);
message['sender_key'] =
(session.senderKey != null && session.senderKey.isNotEmpty)
? session.senderKey
: request.senderKey;
message['sender_claimed_ed25519_key'] =
session.senderClaimedKeys['ed25519'] ??
(session.forwardingCurve25519KeyChain.isEmpty
? keyManager.encryption.fingerprintKey
: null);
message['session_key'] = session.inboundGroupSession
.export_session(session.inboundGroupSession.first_known_index());
// send the actual reply of the key back to the requester
await keyManager.client.sendToDeviceEncrypted(
[requestingDevice],
'm.forwarded_room_key',
message,
);
keyManager.incomingShareRequests.remove(request.requestId);
}
}
RoomKeys _generateUploadKeys(_GenerateUploadKeysArgs args) {
final enc = olm.PkEncryption();
try {
enc.set_recipient_key(args.pubkey);
// first we generate the payload to upload all the session keys in this chunk
final roomKeys = RoomKeys();
for (final dbSession in args.dbSessions) {
final sess = SessionKey.fromDb(dbSession.dbSession, args.userId);
if (!sess.isValid) {
continue;
}
// create the room if it doesn't exist
if (!roomKeys.rooms.containsKey(sess.roomId)) {
roomKeys.rooms[sess.roomId] = RoomKeysRoom();
}
// generate the encrypted content
final payload = <String, dynamic>{
'algorithm': 'm.megolm.v1.aes-sha2',
'forwarding_curve25519_key_chain': sess.forwardingCurve25519KeyChain,
'sender_key': sess.senderKey,
'sender_clencaimed_keys': sess.senderClaimedKeys,
'session_key': sess.inboundGroupSession
.export_session(sess.inboundGroupSession.first_known_index()),
};
// encrypt the content
final encrypted = enc.encrypt(json.encode(payload));
// fetch the device, if available...
//final device = args.client.getUserDeviceKeysByCurve25519Key(sess.senderKey);
// aaaand finally add the session key to our payload
roomKeys.rooms[sess.roomId].sessions[sess.sessionId] = RoomKeysSingleKey(
firstMessageIndex: sess.inboundGroupSession.first_known_index(),
forwardedCount: sess.forwardingCurve25519KeyChain.length,
isVerified: dbSession.verified, //device?.verified ?? false,
sessionData: {
'ephemeral': encrypted.ephemeral,
'ciphertext': encrypted.ciphertext,
'mac': encrypted.mac,
},
);
}
return roomKeys;
} catch (e, s) {
Logs.error('[Key Manager] Error generating payload ' + e.toString(), s);
rethrow;
} finally {
enc.free();
}
}
class _DbInboundGroupSessionBundle {
_DbInboundGroupSessionBundle({this.dbSession, this.verified});
DbInboundGroupSession dbSession;
bool verified;
}
class _GenerateUploadKeysArgs {
_GenerateUploadKeysArgs({this.pubkey, this.dbSessions, this.userId});
String pubkey;
List<_DbInboundGroupSessionBundle> dbSessions;
String userId;
}