502 lines
20 KiB
JavaScript
502 lines
20 KiB
JavaScript
/*
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Copyright 2020 The Matrix.org Foundation C.I.C.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {MEGOLM_ALGORITHM, DecryptionSource} from "./common.js";
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import {groupEventsBySession} from "./megolm/decryption/utils";
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import {mergeMap} from "../../utils/mergeMap";
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import {groupBy} from "../../utils/groupBy";
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import {makeTxnId, formatToDeviceMessagesPayload} from "../common.js";
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const ENCRYPTED_TYPE = "m.room.encrypted";
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// how often ensureMessageKeyIsShared can check if it needs to
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// create a new outbound session
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// note that encrypt could still create a new session
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const MIN_PRESHARE_INTERVAL = 60 * 1000; // 1min
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// TODO: this class is a good candidate for splitting up into encryption and decryption, there doesn't seem to be much overlap
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export class RoomEncryption {
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constructor({room, deviceTracker, olmEncryption, megolmEncryption, megolmDecryption, encryptionParams, storage, keyBackup, notifyMissingMegolmSession, clock}) {
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this._room = room;
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this._deviceTracker = deviceTracker;
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this._olmEncryption = olmEncryption;
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this._megolmEncryption = megolmEncryption;
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this._megolmDecryption = megolmDecryption;
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// content of the m.room.encryption event
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this._encryptionParams = encryptionParams;
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// caches devices to verify events
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this._senderDeviceCache = new Map();
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this._storage = storage;
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this._keyBackup = keyBackup;
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this._notifyMissingMegolmSession = notifyMissingMegolmSession;
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this._clock = clock;
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this._isFlushingRoomKeyShares = false;
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this._lastKeyPreShareTime = null;
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this._keySharePromise = null;
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this._disposed = false;
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}
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enableKeyBackup(keyBackup) {
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if (this._keyBackup && !!keyBackup) {
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return;
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}
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this._keyBackup = keyBackup;
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}
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async restoreMissingSessionsFromBackup(entries, log) {
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const events = entries.filter(e => e.isEncrypted && !e.isDecrypted && e.event).map(e => e.event);
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const eventsBySession = groupEventsBySession(events);
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const groups = Array.from(eventsBySession.values());
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const txn = await this._storage.readTxn([this._storage.storeNames.inboundGroupSessions]);
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const hasSessions = await Promise.all(groups.map(async group => {
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return this._megolmDecryption.hasSession(this._room.id, group.senderKey, group.sessionId, txn);
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}));
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const missingSessions = groups.filter((_, i) => !hasSessions[i]);
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if (missingSessions.length) {
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// start with last sessions which should be for the last items in the timeline
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for (var i = missingSessions.length - 1; i >= 0; i--) {
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const session = missingSessions[i];
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await log.wrap("session", log => this._requestMissingSessionFromBackup(session.senderKey, session.sessionId, log));
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}
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}
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}
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notifyTimelineClosed() {
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this._senderDeviceCache = new Map(); // purge the sender device cache
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}
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async writeMemberChanges(memberChanges, txn, log) {
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let shouldFlush = false;
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const memberChangesArray = Array.from(memberChanges.values());
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// this also clears our session if we leave the room ourselves
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if (memberChangesArray.some(m => m.hasLeft)) {
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log.log({
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l: "discardOutboundSession",
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leftUsers: memberChangesArray.filter(m => m.hasLeft).map(m => m.userId),
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});
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this._megolmEncryption.discardOutboundSession(this._room.id, txn);
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}
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if (memberChangesArray.some(m => m.hasJoined)) {
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shouldFlush = await this._addShareRoomKeyOperationForNewMembers(memberChangesArray, txn, log);
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}
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await this._deviceTracker.writeMemberChanges(this._room, memberChanges, txn);
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return shouldFlush;
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}
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async prepareDecryptAll(events, newKeys, source, txn) {
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const errors = new Map();
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const validEvents = [];
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for (const event of events) {
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if (event.redacted_because || event.unsigned?.redacted_because) {
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continue;
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}
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if (event.content?.algorithm !== MEGOLM_ALGORITHM) {
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errors.set(event.event_id, new Error("Unsupported algorithm: " + event.content?.algorithm));
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}
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validEvents.push(event);
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}
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const preparation = await this._megolmDecryption.prepareDecryptAll(
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this._room.id, validEvents, newKeys, txn);
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return new DecryptionPreparation(preparation, errors, source, this, events);
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}
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async _processDecryptionResults(events, results, errors, source, txn, log) {
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const missingSessionEvents = events.filter(event => {
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const error = errors.get(event.event_id);
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return error?.code === "MEGOLM_NO_SESSION";
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});
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if (!missingSessionEvents.length) {
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return;
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}
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// store missing event ids if received from sync
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const missingEventsBySession = groupEventsBySession(missingSessionEvents);
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if (source === DecryptionSource.Sync) {
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await Promise.all(Array.from(missingEventsBySession.values()).map(async group => {
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const eventIds = group.events.map(e => e.event_id);
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return this._megolmDecryption.addMissingKeyEventIds(
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this._room.id, group.senderKey, group.sessionId, eventIds, txn);
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}));
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}
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if (!this._keyBackup) {
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return;
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}
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log.wrapDetached("check key backup", async log => {
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// if the message came from sync, wait 10s to see if the room key arrives late,
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// and only after that proceed to request from backup
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log.set("source", source);
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log.set("events", missingSessionEvents.length);
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log.set("sessions", missingEventsBySession.size);
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if (source === DecryptionSource.Sync) {
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await this._clock.createTimeout(10000).elapsed();
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if (this._disposed) {
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return;
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}
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// now check which sessions have been received already
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const txn = await this._storage.readTxn([this._storage.storeNames.inboundGroupSessions]);
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await Promise.all(Array.from(missingEventsBySession).map(async ([key, group]) => {
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if (await this._megolmDecryption.hasSession(this._room.id, group.senderKey, group.sessionId, txn)) {
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missingEventsBySession.delete(key);
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}
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}));
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}
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await Promise.all(Array.from(missingEventsBySession.values()).map(group => {
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return log.wrap("session", log => this._requestMissingSessionFromBackup(group.senderKey, group.sessionId, log));
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}));
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});
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}
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async _verifyDecryptionResult(result, txn) {
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let device = this._senderDeviceCache.get(result.senderCurve25519Key);
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if (!device) {
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device = await this._deviceTracker.getDeviceByCurve25519Key(result.senderCurve25519Key, txn);
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this._senderDeviceCache.set(result.senderCurve25519Key, device);
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}
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if (device) {
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result.setDevice(device);
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} else if (!this._room.isTrackingMembers) {
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result.setRoomNotTrackedYet();
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}
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}
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async _requestMissingSessionFromBackup(senderKey, sessionId, log) {
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// show prompt to enable secret storage
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if (!this._keyBackup) {
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log.set("enabled", false);
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this._notifyMissingMegolmSession();
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return;
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}
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log.set("id", sessionId);
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log.set("senderKey", senderKey);
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try {
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const roomKey = await this._keyBackup.getRoomKey(this._room.id, sessionId, log);
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if (roomKey) {
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if (roomKey.senderKey !== senderKey) {
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log.set("wrong_sender_key", roomKey.senderKey);
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log.logLevel = log.level.Warn;
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return;
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}
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let keyIsBestOne = false;
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let retryEventIds;
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const txn = await this._storage.readWriteTxn([this._storage.storeNames.inboundGroupSessions]);
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try {
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keyIsBestOne = await this._megolmDecryption.writeRoomKey(roomKey, txn);
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log.set("isBetter", keyIsBestOne);
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if (keyIsBestOne) {
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retryEventIds = roomKey.eventIds;
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}
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} catch (err) {
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txn.abort();
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throw err;
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}
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await txn.complete();
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if (keyIsBestOne) {
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await log.wrap("retryDecryption", log => this._room.notifyRoomKey(roomKey, retryEventIds || [], log));
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}
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}
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} catch (err) {
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if (!(err.name === "HomeServerError" && err.errcode === "M_NOT_FOUND")) {
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log.set("not_found", true);
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} else {
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log.error = err;
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log.logLevel = log.level.Error;
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}
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}
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}
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/**
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* @param {RoomKey} roomKeys
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* @param {Transaction} txn
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* @return {Promise<Array<string>>} the event ids that should be retried to decrypt
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*/
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getEventIdsForMissingKey(roomKey, txn) {
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return this._megolmDecryption.getEventIdsForMissingKey(this._room.id, roomKey.senderKey, roomKey.sessionId, txn);
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}
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/** shares the encryption key for the next message if needed */
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async ensureMessageKeyIsShared(hsApi, log) {
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if (this._lastKeyPreShareTime?.measure() < MIN_PRESHARE_INTERVAL) {
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return;
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}
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this._lastKeyPreShareTime = this._clock.createMeasure();
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try {
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this._keySharePromise = (async () => {
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const roomKeyMessage = await this._megolmEncryption.ensureOutboundSession(this._room.id, this._encryptionParams);
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if (roomKeyMessage) {
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this._keyBackup?.flush(log);
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await log.wrap("share key", log => this._shareNewRoomKey(roomKeyMessage, hsApi, log));
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}
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})();
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await this._keySharePromise;
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} finally {
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this._keySharePromise = null;
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}
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}
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async encrypt(type, content, hsApi, log) {
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// ensureMessageKeyIsShared is still running,
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// wait for it to create and share a key if needed
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if (this._keySharePromise) {
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log.set("waitForRunningKeyShare", true);
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await this._keySharePromise;
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}
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const megolmResult = await log.wrap("megolm encrypt", () => this._megolmEncryption.encrypt(this._room.id, type, content, this._encryptionParams));
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if (megolmResult.roomKeyMessage) {
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this._keyBackup?.flush(log);
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await log.wrap("share key", log => this._shareNewRoomKey(megolmResult.roomKeyMessage, hsApi, log));
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}
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return {
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type: ENCRYPTED_TYPE,
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content: megolmResult.content
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};
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}
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needsToShareKeys(memberChanges) {
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for (const m of memberChanges.values()) {
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if (m.hasJoined) {
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return true;
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}
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}
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return false;
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}
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async _shareNewRoomKey(roomKeyMessage, hsApi, log) {
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let writeOpTxn = await this._storage.readWriteTxn([this._storage.storeNames.operations]);
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let operation;
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try {
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operation = this._writeRoomKeyShareOperation(roomKeyMessage, null, writeOpTxn);
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} catch (err) {
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writeOpTxn.abort();
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throw err;
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}
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// TODO: at this point we have the room key stored, and the rest is sort of optional
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// it would be nice if we could signal SendQueue that any error from here on is non-fatal and
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// return the encrypted payload.
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await this._processShareRoomKeyOperation(operation, hsApi, log);
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}
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async _addShareRoomKeyOperationForNewMembers(memberChangesArray, txn, log) {
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const userIds = memberChangesArray.filter(m => m.hasJoined).map(m => m.userId);
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const roomKeyMessage = await this._megolmEncryption.createRoomKeyMessage(
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this._room.id, txn);
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if (roomKeyMessage) {
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log.log({
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l: "share key for new members", userIds,
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id: roomKeyMessage.session_id,
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chain_index: roomKeyMessage.chain_index
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});
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this._writeRoomKeyShareOperation(roomKeyMessage, userIds, txn);
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return true;
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}
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return false;
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}
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async flushPendingRoomKeyShares(hsApi, operations, log) {
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// this has to be reentrant as it can be called from Room.start while still running
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if (this._isFlushingRoomKeyShares) {
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return;
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}
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this._isFlushingRoomKeyShares = true;
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try {
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if (!operations) {
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const txn = await this._storage.readTxn([this._storage.storeNames.operations]);
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operations = await txn.operations.getAllByTypeAndScope("share_room_key", this._room.id);
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}
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for (const operation of operations) {
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// just to be sure
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if (operation.type !== "share_room_key") {
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continue;
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}
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await log.wrap("operation", log => this._processShareRoomKeyOperation(operation, hsApi, log));
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}
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} finally {
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this._isFlushingRoomKeyShares = false;
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}
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}
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_writeRoomKeyShareOperation(roomKeyMessage, userIds, txn) {
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const id = Math.floor(Math.random() * Number.MAX_SAFE_INTEGER).toString();
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const operation = {
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id,
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type: "share_room_key",
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scope: this._room.id,
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userIds,
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roomKeyMessage,
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};
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txn.operations.add(operation);
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return operation;
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}
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async _processShareRoomKeyOperation(operation, hsApi, log) {
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log.set("id", operation.id);
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await this._deviceTracker.trackRoom(this._room, log);
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let devices;
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if (operation.userIds === null) {
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devices = await this._deviceTracker.devicesForTrackedRoom(this._room.id, hsApi, log);
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const userIds = Array.from(devices.reduce((set, device) => set.add(device.userId), new Set()));
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operation.userIds = userIds;
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await this._updateOperationsStore(operations => operations.update(operation));
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} else {
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devices = await this._deviceTracker.devicesForRoomMembers(this._room.id, operation.userIds, hsApi, log);
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}
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const messages = await log.wrap("olm encrypt", log => this._olmEncryption.encrypt(
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"m.room_key", operation.roomKeyMessage, devices, hsApi, log));
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const missingDevices = devices.filter(d => !messages.some(m => m.device === d));
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await log.wrap("send", log => this._sendMessagesToDevices(ENCRYPTED_TYPE, messages, hsApi, log));
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if (missingDevices.length) {
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await log.wrap("missingDevices", async log => {
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log.set("devices", missingDevices.map(d => d.deviceId));
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const unsentUserIds = operation.userIds.filter(userId => missingDevices.some(d => d.userId === userId));
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log.set("unsentUserIds", unsentUserIds);
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operation.userIds = unsentUserIds;
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// first remove the users that we've sent the keys already from the operation,
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// so if anything fails, we don't send them again
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await this._updateOperationsStore(operations => operations.update(operation));
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// now, let the devices we could not claim their key
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const withheldMessage = this._megolmEncryption.createWithheldMessage(operation.roomKeyMessage, "m.no_olm", "OTKs exhausted");
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await this._sendSharedMessageToDevices("org.matrix.room_key.withheld", withheldMessage, missingDevices, hsApi, log);
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});
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}
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await this._updateOperationsStore(operations => operations.remove(operation.id));
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}
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async _updateOperationsStore(callback) {
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const writeTxn = await this._storage.readWriteTxn([this._storage.storeNames.operations]);
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try {
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callback(writeTxn.operations);
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} catch (err) {
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writeTxn.abort();
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throw err;
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}
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await writeTxn.complete();
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}
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// TODO: make this use _sendMessagesToDevices
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async _sendSharedMessageToDevices(type, message, devices, hsApi, log) {
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const devicesByUser = groupBy(devices, device => device.userId);
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const payload = {
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messages: Array.from(devicesByUser.entries()).reduce((userMap, [userId, devices]) => {
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userMap[userId] = devices.reduce((deviceMap, device) => {
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deviceMap[device.deviceId] = message;
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return deviceMap;
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}, {});
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return userMap;
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}, {})
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};
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const txnId = makeTxnId();
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await hsApi.sendToDevice(type, payload, txnId, {log}).response();
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}
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async _sendMessagesToDevices(type, messages, hsApi, log) {
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log.set("messages", messages.length);
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const payload = formatToDeviceMessagesPayload(messages);
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const txnId = makeTxnId();
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await hsApi.sendToDevice(type, payload, txnId, {log}).response();
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}
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filterUndecryptedEventEntriesForKeys(entries, keys) {
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return entries.filter(entry => {
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if (entry.isEncrypted && !entry.isDecrypted) {
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const {event} = entry;
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if (event) {
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const senderKey = event.content?.["sender_key"];
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const sessionId = event.content?.["session_id"];
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return keys.some(key => senderKey === key.senderKey && sessionId === key.sessionId);
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}
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}
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return false;
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});
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}
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dispose() {
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this._disposed = true;
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}
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}
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/**
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* wrappers around megolm decryption classes to be able to post-process
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* the decryption results before turning them
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*/
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class DecryptionPreparation {
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constructor(megolmDecryptionPreparation, extraErrors, source, roomEncryption, events) {
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this._megolmDecryptionPreparation = megolmDecryptionPreparation;
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this._extraErrors = extraErrors;
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this._source = source;
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this._roomEncryption = roomEncryption;
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this._events = events;
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}
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async decrypt() {
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return new DecryptionChanges(
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await this._megolmDecryptionPreparation.decrypt(),
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this._extraErrors,
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this._source,
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this._roomEncryption,
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this._events);
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}
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dispose() {
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this._megolmDecryptionPreparation.dispose();
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}
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}
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class DecryptionChanges {
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constructor(megolmDecryptionChanges, extraErrors, source, roomEncryption, events) {
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this._megolmDecryptionChanges = megolmDecryptionChanges;
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this._extraErrors = extraErrors;
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this._source = source;
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this._roomEncryption = roomEncryption;
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this._events = events;
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}
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async write(txn, log) {
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const {results, errors} = await this._megolmDecryptionChanges.write(txn);
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mergeMap(this._extraErrors, errors);
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await this._roomEncryption._processDecryptionResults(this._events, results, errors, this._source, txn, log);
|
|
return new BatchDecryptionResult(results, errors, this._roomEncryption);
|
|
}
|
|
}
|
|
|
|
class BatchDecryptionResult {
|
|
constructor(results, errors, roomEncryption) {
|
|
this.results = results;
|
|
this.errors = errors;
|
|
this._roomEncryption = roomEncryption;
|
|
}
|
|
|
|
applyToEntries(entries) {
|
|
for (const entry of entries) {
|
|
const result = this.results.get(entry.id);
|
|
if (result) {
|
|
entry.setDecryptionResult(result);
|
|
} else {
|
|
const error = this.errors.get(entry.id);
|
|
if (error) {
|
|
entry.setDecryptionError(error);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
verifySenders(txn) {
|
|
return Promise.all(Array.from(this.results.values()).map(result => {
|
|
return this._roomEncryption._verifyDecryptionResult(result, txn);
|
|
}));
|
|
}
|
|
}
|