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expose multi-step decryption from RoomEncryption, adjust room timeline

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sync code hasn't been adjusted yet
This commit is contained in:
Bruno Windels 2020-09-10 12:09:17 +02:00
parent 7c1f9dbed0
commit 1c77c3b876
5 changed files with 199 additions and 133 deletions
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136
src/matrix/e2ee/RoomEncryption.js
View file

@ -14,8 +14,9 @@ See the License for the specific language governing permissions and
limitations under the License.
*/
import {MEGOLM_ALGORITHM} from "./common.js";
import {MEGOLM_ALGORITHM, DecryptionSource} from "./common.js";
import {groupBy} from "../../utils/groupBy.js";
import {mergeMap} from "../../utils/mergeMap.js";
import {makeTxnId} from "../common.js";
const ENCRYPTED_TYPE = "m.room.encrypted";
@ -55,23 +56,54 @@ export class RoomEncryption {
return await this._deviceTracker.writeMemberChanges(this._room, memberChanges, txn);
}
async decrypt(event, isSync, isTimelineOpen, retryData, txn) {
if (event.redacted_because || event.unsigned?.redacted_because) {
return;
// this happens before entries exists, as they are created by the syncwriter
// but we want to be able to map it back to something in the timeline easily
// when retrying decryption.
async prepareDecryptAll(events, source, isTimelineOpen, txn) {
const errors = [];
const validEvents = [];
for (const event of events) {
if (event.redacted_because || event.unsigned?.redacted_because) {
continue;
}
if (event.content?.algorithm !== MEGOLM_ALGORITHM) {
errors.set(event.event_id, new Error("Unsupported algorithm: " + event.content?.algorithm));
}
validEvents.push(event);
}
if (event.content?.algorithm !== MEGOLM_ALGORITHM) {
throw new Error("Unsupported algorithm: " + event.content?.algorithm);
let customCache;
let sessionCache;
if (source === DecryptionSource.Sync) {
sessionCache = this._megolmSyncCache;
} else if (source === DecryptionSource.Timeline) {
sessionCache = this._megolmBackfillCache;
} else if (source === DecryptionSource.Retry) {
// when retrying, we could have mixed events from at the bottom of the timeline (sync)
// and somewhere else, so create a custom cache we use just for this operation.
customCache = this._megolmEncryption.createSessionCache();
sessionCache = customCache;
} else {
throw new Error("Unknown source: " + source);
}
let sessionCache = isSync ? this._megolmSyncCache : this._megolmBackfillCache;
const result = await this._megolmDecryption.decrypt(
this._room.id, event, sessionCache, txn);
if (!result) {
this._addMissingSessionEvent(event, isSync, retryData);
const preparation = await this._megolmDecryption.prepareDecryptAll(
this._room.id, validEvents, sessionCache, txn);
if (customCache) {
customCache.dispose();
}
if (result && isTimelineOpen) {
await this._verifyDecryptionResult(result, txn);
return new DecryptionPreparation(preparation, errors, {isTimelineOpen}, this);
}
async _processDecryptionResults(results, errors, flags, txn) {
for (const error of errors.values()) {
if (error.code === "MEGOLM_NO_SESSION") {
this._addMissingSessionEvent(error.event);
}
}
if (flags.isTimelineOpen) {
for (const result of results.values()) {
await this._verifyDecryptionResult(result, txn);
}
}
return result;
}
async _verifyDecryptionResult(result, txn) {
@ -87,30 +119,30 @@ export class RoomEncryption {
}
}
_addMissingSessionEvent(event, isSync, data) {
_addMissingSessionEvent(event) {
const senderKey = event.content?.["sender_key"];
const sessionId = event.content?.["session_id"];
const key = `${senderKey}|${sessionId}`;
let eventIds = this._eventIdsByMissingSession.get(key);
if (!eventIds) {
eventIds = new Map();
eventIds = new Set();
this._eventIdsByMissingSession.set(key, eventIds);
}
eventIds.set(event.event_id, {data, isSync});
eventIds.add(event.event_id);
}
applyRoomKeys(roomKeys) {
// retry decryption with the new sessions
const retryEntries = [];
const retryEventIds = [];
for (const roomKey of roomKeys) {
const key = `${roomKey.senderKey}|${roomKey.sessionId}`;
const entriesForSession = this._eventIdsByMissingSession.get(key);
if (entriesForSession) {
this._eventIdsByMissingSession.delete(key);
retryEntries.push(...entriesForSession.values());
retryEventIds.push(...entriesForSession);
}
}
return retryEntries;
return retryEventIds;
}
async encrypt(type, content, hsApi) {
@ -214,3 +246,67 @@ export class RoomEncryption {
await hsApi.sendToDevice(type, payload, txnId).response();
}
}
/**
* wrappers around megolm decryption classes to be able to post-process
* the decryption results before turning them
*/
class DecryptionPreparation {
constructor(megolmDecryptionPreparation, extraErrors, flags, roomEncryption) {
this._megolmDecryptionPreparation = megolmDecryptionPreparation;
this._extraErrors = extraErrors;
this._flags = flags;
this._roomEncryption = roomEncryption;
}
async decrypt() {
return new DecryptionChanges(
await this._megolmDecryptionPreparation.decrypt(),
this._extraErrors,
this._flags,
this._roomEncryption);
}
dispose() {
this._megolmDecryptionChanges.dispose();
}
}
class DecryptionChanges {
constructor(megolmDecryptionChanges, extraErrors, flags, roomEncryption) {
this._megolmDecryptionChanges = megolmDecryptionChanges;
this._extraErrors = extraErrors;
this._flags = flags;
this._roomEncryption = roomEncryption;
}
async write(txn) {
const {results, errors} = await this._megolmDecryptionChanges.write(txn);
mergeMap(this._extraErrors, errors);
await this._roomEncryption._processDecryptionResults(results, errors, this._flags, txn);
return new BatchDecryptionResult(results, errors);
}
}
class BatchDecryptionResult {
constructor(results, errors) {
this.results = results;
this.errors = errors;
console.log("BatchDecryptionResult", this);
}
applyToEntries(entries) {
console.log("BatchDecryptionResult.applyToEntries", this);
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);
}
}
}
}
}

3
src/matrix/e2ee/common.js
View file

@ -15,6 +15,9 @@ limitations under the License.
*/
import anotherjson from "../../../lib/another-json/index.js";
import {createEnum} from "../../utils/enum.js";
export const DecryptionSource = createEnum(["Sync", "Timeline", "Retry"]);
// use common prefix so it's easy to clear properties that are not e2ee related during session clear
export const SESSION_KEY_PREFIX = "e2ee:";

116
src/matrix/room/Room.js
View file

@ -26,6 +26,9 @@ import {fetchOrLoadMembers} from "./members/load.js";
import {MemberList} from "./members/MemberList.js";
import {Heroes} from "./members/Heroes.js";
import {EventEntry} from "./timeline/entries/EventEntry.js";
import {DecryptionSource} from "../e2ee/common.js";
const EVENT_ENCRYPTED_TYPE = "m.room.encrypted";
export class Room extends EventEmitter {
constructor({roomId, storage, hsApi, emitCollectionChange, sendScheduler, pendingEvents, user, createRoomEncryption, getSyncToken}) {
@ -49,43 +52,26 @@ export class Room extends EventEmitter {
async notifyRoomKeys(roomKeys) {
if (this._roomEncryption) {
// array of {data, isSync}
let retryEntries = this._roomEncryption.applyRoomKeys(roomKeys);
let decryptedEntries = [];
if (retryEntries.length) {
// groupSessionDecryptions can be written, the other stores not
const txn = await this._storage.readWriteTxn([
let retryEventIds = this._roomEncryption.applyRoomKeys(roomKeys);
if (retryEventIds.length) {
const retryEntries = [];
const txn = await this._storage.readTxn([
this._storage.storeNames.timelineEvents,
this._storage.storeNames.inboundGroupSessions,
this._storage.storeNames.groupSessionDecryptions,
this._storage.storeNames.deviceIdentities,
]);
try {
for (const retryEntry of retryEntries) {
const {data: eventKey} = retryEntry;
let entry = this._timeline?.findEntry(eventKey);
if (!entry) {
const storageEntry = await txn.timelineEvents.get(this._roomId, eventKey);
if (storageEntry) {
entry = new EventEntry(storageEntry, this._fragmentIdComparer);
}
}
if (entry) {
entry = await this._decryptEntry(entry, txn, retryEntry.isSync);
decryptedEntries.push(entry);
}
for (const eventId of retryEventIds) {
const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
if (storageEntry) {
retryEntries.push(new EventEntry(storageEntry, this._fragmentIdComparer));
}
} catch (err) {
txn.abort();
throw err;
}
await txn.complete();
await this._decryptEntries(DecryptionSource.Retry, retryEntries, txn);
if (this._timeline) {
// only adds if already present
this._timeline.replaceEntries(retryEntries);
}
// pass decryptedEntries to roomSummary
}
if (this._timeline) {
// only adds if already present
this._timeline.replaceEntries(decryptedEntries);
}
// pass decryptedEntries to roomSummary
}
}
@ -94,22 +80,42 @@ export class Room extends EventEmitter {
if (this._roomEncryption) {
this._sendQueue.enableEncryption(this._roomEncryption);
if (this._timeline) {
this._timeline.enableEncryption(this._decryptEntries.bind(this));
this._timeline.enableEncryption(this._decryptEntries.bind(this, DecryptionSource.Timeline));
}
}
}
async _decryptEntry(entry, txn, isSync) {
if (entry.eventType === "m.room.encrypted") {
try {
const decryptionResult = await this._roomEncryption.decrypt(
entry.event, isSync, !!this._timeline, entry.asEventKey(), txn);
if (decryptionResult) {
entry.setDecryptionResult(decryptionResult);
}
} catch (err) {
console.warn("event decryption error", err, entry.event);
entry.setDecryptionError(err);
/**
* Used for decrypting when loading/filling the timeline, and retrying decryption,
* not during sync, where it is split up during the multiple phases.
*/
async _decryptEntries(source, entries, inboundSessionTxn = null) {
if (!inboundSessionTxn) {
inboundSessionTxn = await this._storage.readTxn([this._storage.storeNames.inboundGroupSessions]);
}
const events = entries.filter(entry => {
return entry.eventType === EVENT_ENCRYPTED_TYPE;
}).map(entry => entry.event);
const isTimelineOpen = this._isTimelineOpen;
const preparation = await this._roomEncryption.prepareDecryptAll(events, source, isTimelineOpen, inboundSessionTxn);
const changes = await preparation.decrypt();
const stores = [this._storage.storeNames.groupSessionDecryptions];
if (isTimelineOpen) {
// read to fetch devices if timeline is open
stores.push(this._storage.storeNames.deviceIdentities);
}
const writeTxn = await this._storage.readWriteTxn(stores);
let decryption;
try {
decryption = await changes.write(writeTxn);
} catch (err) {
writeTxn.abort();
throw err;
}
await writeTxn.complete();
decryption.applyToEntries(entries);
}
}
}
return entry;
@ -299,19 +305,11 @@ export class Room extends EventEmitter {
}
}).response();
let stores = [
const txn = await this._storage.readWriteTxn([
this._storage.storeNames.pendingEvents,
this._storage.storeNames.timelineEvents,
this._storage.storeNames.timelineFragments,
];
if (this._roomEncryption) {
stores = stores.concat([
this._storage.storeNames.inboundGroupSessions,
this._storage.storeNames.groupSessionDecryptions,
this._storage.storeNames.deviceIdentities,
]);
}
const txn = await this._storage.readWriteTxn(stores);
]);
let removedPendingEvents;
let gapResult;
try {
@ -324,14 +322,14 @@ export class Room extends EventEmitter {
fragmentIdComparer: this._fragmentIdComparer,
});
gapResult = await gapWriter.writeFragmentFill(fragmentEntry, response, txn);
if (this._roomEncryption) {
gapResult.entries = await this._decryptEntries(gapResult.entries, txn, false);
}
} catch (err) {
txn.abort();
throw err;
}
await txn.complete();
if (this._roomEncryption) {
await this._decryptEntries(DecryptionSource.Timeline, gapResult.entries);
}
// once txn is committed, update in-memory state & emit events
for (const fragment of gapResult.fragments) {
this._fragmentIdComparer.add(fragment);
@ -406,6 +404,10 @@ export class Room extends EventEmitter {
}
}
get _isTimelineOpen() {
return !!this._timeline;
}
async clearUnread() {
if (this.isUnread || this.notificationCount) {
const txn = await this._storage.readWriteTxn([
@ -458,7 +460,7 @@ export class Room extends EventEmitter {
user: this._user,
});
if (this._roomEncryption) {
this._timeline.enableEncryption(this._decryptEntries.bind(this));
this._timeline.enableEncryption(this._decryptEntries.bind(this, DecryptionSource.Timeline));
}
await this._timeline.load();
return this._timeline;

15
src/matrix/room/timeline/Timeline.js
View file

@ -46,21 +46,6 @@ export class Timeline {
this._remoteEntries.setManySorted(entries);
}
findEntry(eventKey) {
// a storage event entry has a fragmentId and eventIndex property, used for sorting,
// just like an EventKey, so this will work, but perhaps a bit brittle.
const entry = new EventEntry(eventKey, this._fragmentIdComparer);
try {
const idx = this._remoteEntries.indexOf(entry);
if (idx !== -1) {
return this._remoteEntries.get(idx);
}
} catch (err) {
// fragmentIdComparer threw, ignore
return;
}
}
replaceEntries(entries) {
for (const entry of entries) {
this._remoteEntries.replace(entry);

62
src/matrix/room/timeline/persistence/TimelineReader.js
View file

@ -32,34 +32,19 @@ export class TimelineReader {
}
_openTxn() {
const stores = [
this._storage.storeNames.timelineEvents,
this._storage.storeNames.timelineFragments,
];
if (this._decryptEntries) {
return this._storage.readWriteTxn([
this._storage.storeNames.timelineEvents,
this._storage.storeNames.timelineFragments,
this._storage.storeNames.inboundGroupSessions,
this._storage.storeNames.groupSessionDecryptions,
this._storage.storeNames.deviceIdentities,
]);
} else {
return this._storage.readTxn([
this._storage.storeNames.timelineEvents,
this._storage.storeNames.timelineFragments,
]);
stores.push(this._storage.storeNames.inboundGroupSessions);
}
return this._storage.readTxn(stores);
}
async readFrom(eventKey, direction, amount) {
const txn = await this._openTxn();
let entries;
try {
entries = await this._readFrom(eventKey, direction, amount, txn);
} catch (err) {
txn.abort();
throw err;
}
await txn.complete();
return entries;
return await this._readFrom(eventKey, direction, amount, txn);
}
async _readFrom(eventKey, direction, amount, txn) {
@ -75,9 +60,6 @@ export class TimelineReader {
eventsWithinFragment = await timelineStore.eventsBefore(this._roomId, eventKey, amount);
}
let eventEntries = eventsWithinFragment.map(e => new EventEntry(e, this._fragmentIdComparer));
if (this._decryptEntries) {
eventEntries = await this._decryptEntries(eventEntries, txn);
}
entries = directionalConcat(entries, eventEntries, direction);
// prepend or append eventsWithinFragment to entries, and wrap them in EventEntry
@ -100,29 +82,27 @@ export class TimelineReader {
}
}
if (this._decryptEntries) {
await this._decryptEntries(entries, txn);
}
return entries;
}
async readFromEnd(amount) {
const txn = await this._openTxn();
const liveFragment = await txn.timelineFragments.liveFragment(this._roomId);
let entries;
try {
const liveFragment = await txn.timelineFragments.liveFragment(this._roomId);
// room hasn't been synced yet
if (!liveFragment) {
entries = [];
} else {
this._fragmentIdComparer.add(liveFragment);
const liveFragmentEntry = FragmentBoundaryEntry.end(liveFragment, this._fragmentIdComparer);
const eventKey = liveFragmentEntry.asEventKey();
entries = await this._readFrom(eventKey, Direction.Backward, amount, txn);
entries.unshift(liveFragmentEntry);
}
} catch (err) {
txn.abort();
throw err;
// room hasn't been synced yet
if (!liveFragment) {
entries = [];
} else {
this._fragmentIdComparer.add(liveFragment);
const liveFragmentEntry = FragmentBoundaryEntry.end(liveFragment, this._fragmentIdComparer);
const eventKey = liveFragmentEntry.asEventKey();
entries = await this._readFrom(eventKey, Direction.Backward, amount, txn);
entries.unshift(liveFragmentEntry);
}
await txn.complete();
return entries;
}
}