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implement room key sharing with operations store

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This commit is contained in:
Bruno Windels 2020-09-11 14:41:12 +02:00
parent b00865510f
commit ab1fe711ad
3 changed files with 86 additions and 65 deletions
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4
src/matrix/Sync.js
View file

@ -226,7 +226,9 @@ export class Sync {
storeNames.groupSessionDecryptions,
storeNames.deviceIdentities,
// to discard outbound session when somebody leaves a room
storeNames.outboundGroupSessions
// and to create room key messages when somebody leaves
storeNames.outboundGroupSessions,
storeNames.operations
]);
}

138
src/matrix/e2ee/RoomEncryption.js
View file

@ -47,13 +47,14 @@ export class RoomEncryption {
}
async writeMemberChanges(memberChanges, txn) {
for (const m of memberChanges.values()) {
if (m.hasLeft) {
const memberChangesArray = Array.from(memberChanges.values());
if (memberChangesArray.some(m => m.hasLeft)) {
this._megolmEncryption.discardOutboundSession(this._room.id, txn);
break;
}
if (memberChangesArray.some(m => m.hasJoined)) {
await this._addShareRoomKeyOperationForNewMembers(memberChangesArray, txn);
}
return await this._deviceTracker.writeMemberChanges(this._room, memberChanges, txn);
await this._deviceTracker.writeMemberChanges(this._room, memberChanges, txn);
}
// this happens before entries exists, as they are created by the syncwriter
@ -146,16 +147,10 @@ export class RoomEncryption {
}
async encrypt(type, content, hsApi) {
const megolmResult = await this._megolmEncryption.encrypt(this._room.id, type, content, this._encryptionParams);
// share the new megolm session if needed
if (megolmResult.roomKeyMessage) {
await this._deviceTracker.trackRoom(this._room);
const devices = await this._deviceTracker.devicesForTrackedRoom(this._room.id, hsApi);
await this._sendRoomKey(megolmResult.roomKeyMessage, devices, hsApi);
// if we happen to rotate the session before we have sent newly joined members the room key
// then mark those members as not needing the key anymore
const userIds = Array.from(devices.reduce((set, device) => set.add(device.userId), new Set()));
await this._clearNeedsRoomKeyFlag(userIds);
const megolmResult = await this._megolmEncryption.encrypt(this._room.id, type, content, this._encryptionParams);
if (megolmResult.roomKeyMessage) {
this._shareNewRoomKey(megolmResult.roomKeyMessage, hsApi);
}
return {
type: ENCRYPTED_TYPE,
@ -165,64 +160,87 @@ export class RoomEncryption {
needsToShareKeys(memberChanges) {
for (const m of memberChanges.values()) {
if (m.member.needsRoomKey) {
if (m.hasJoined) {
return true;
}
}
return false;
}
async shareRoomKeyToPendingMembers(hsApi) {
// sucks to call this for all encrypted rooms on startup?
const txn = await this._storage.readTxn([this._storage.storeNames.roomMembers]);
const pendingUserIds = await txn.roomMembers.getUserIdsNeedingRoomKey(this._room.id);
return await this._shareRoomKey(pendingUserIds, hsApi);
}
async _shareNewRoomKey(roomKeyMessage, hsApi) {
const devices = await this._deviceTracker.devicesForTrackedRoom(this._room.id, hsApi);
const userIds = Array.from(devices.reduce((set, device) => set.add(device.userId), new Set()));
async shareRoomKeyForMemberChanges(memberChanges, hsApi) {
const pendingUserIds = [];
for (const m of memberChanges.values()) {
if (m.member.needsRoomKey) {
pendingUserIds.push(m.userId);
}
}
return await this._shareRoomKey(pendingUserIds, hsApi);
}
async _shareRoomKey(userIds, hsApi) {
if (userIds.length === 0) {
return;
}
const readRoomKeyTxn = await this._storage.readTxn([this._storage.storeNames.outboundGroupSessions]);
const roomKeyMessage = await this._megolmEncryption.createRoomKeyMessage(this._room.id, readRoomKeyTxn);
// no room key if we haven't created a session yet
// (or we removed it and will create a new one on the next send)
if (roomKeyMessage) {
const devices = await this._deviceTracker.devicesForRoomMembers(this._room.id, userIds, hsApi);
await this._sendRoomKey(roomKeyMessage, devices, hsApi);
const actuallySentUserIds = Array.from(devices.reduce((set, device) => set.add(device.userId), new Set()));
await this._clearNeedsRoomKeyFlag(actuallySentUserIds);
} else {
// we don't have a session yet, clear them all
await this._clearNeedsRoomKeyFlag(userIds);
}
}
async _clearNeedsRoomKeyFlag(userIds) {
const txn = await this._storage.readWriteTxn([this._storage.storeNames.roomMembers]);
// store operation for room key share, in case we don't finish here
const writeOpTxn = await this._storage.readWriteTxn([this._storage.storeNames.operations]);
let operationId;
try {
await Promise.all(userIds.map(async userId => {
const memberData = await txn.roomMembers.get(this._room.id, userId);
if (memberData.needsRoomKey) {
memberData.needsRoomKey = false;
txn.roomMembers.set(memberData);
}
}));
operationId = this._writeRoomKeyShareOperation(roomKeyMessage, userIds, writeOpTxn);
} catch (err) {
txn.abort();
writeOpTxn.abort();
throw err;
}
await txn.complete();
await writeOpTxn.complete();
// TODO: at this point we have the room key stored, and the rest is sort of optional
// it would be nice if we could signal SendQueue that any error from here on is non-fatal and
// return the encrypted payload.
// send the room key
await this._sendRoomKey(roomKeyMessage, devices, hsApi);
// remove the operation
const removeOpTxn = await this._storage.readWriteTxn([this._storage.storeNames.operations]);
try {
removeOpTxn.operations.remove(operationId);
} catch (err) {
removeOpTxn.abort();
throw err;
}
await removeOpTxn.complete();
}
async _addShareRoomKeyOperationForNewMembers(memberChangesArray, txn) {
const userIds = memberChangesArray.filter(m => m.hasJoined).map(m => m.userId);
const roomKeyMessage = await this._megolmEncryption.createRoomKeyMessage(
this._room.id, txn);
if (roomKeyMessage) {
this._writeRoomKeyShareOperation(roomKeyMessage, userIds, txn);
}
}
_writeRoomKeyShareOperation(roomKeyMessage, userIds, txn) {
const id = Math.floor(Math.random() * Number.MAX_SAFE_INTEGER).toString();
txn.operations.add({
id,
type: "share_room_key",
scope: this._room.id,
userIds,
roomKeyMessage,
});
return id;
}
async flushPendingRoomKeyShares(hsApi, operations = null) {
if (!operations) {
const txn = await this._storage.readTxn([this._storage.storeNames.operations]);
operations = await txn.operations.getAllByTypeAndScope("share_room_key", this._room.id);
}
for (const operation of operations) {
// just to be sure
if (operation.type !== "share_room_key") {
continue;
}
const devices = await this._deviceTracker.devicesForRoomMembers(this._room.id, operation.userIds, hsApi);
await this._sendRoomKey(operation.roomKeyMessage, devices, hsApi);
const removeTxn = await this._storage.readWriteTxn([this._storage.storeNames.operations]);
try {
removeTxn.operations.remove(operation.id);
} catch (err) {
removeTxn.abort();
throw err;
}
await removeTxn.complete();
}
}
async _sendRoomKey(roomKeyMessage, devices, hsApi) {

7
src/matrix/room/Room.js
View file

@ -243,7 +243,8 @@ export class Room extends EventEmitter {
}
needsAfterSyncCompleted({memberChanges}) {
return this._roomEncryption?.needsToShareKeys(memberChanges);
const result = this._roomEncryption?.needsToShareKeys(memberChanges);
return result;
}
/**
@ -251,9 +252,9 @@ export class Room extends EventEmitter {
* Can be used to do longer running operations that resulted from the last sync,
* like network operations.
*/
async afterSyncCompleted({memberChanges}) {
async afterSyncCompleted() {
if (this._roomEncryption) {
await this._roomEncryption.shareRoomKeyForMemberChanges(memberChanges, this._hsApi);
await this._roomEncryption.flushPendingRoomKeyShares(this._hsApi);
}
}