Merge pull request #77 from vector-im/bwindels/devicetracking

Implement device tracking for E2EE rooms

src/matrix/Session.js

@@ -19,6 +19,7 @@ import { ObservableMap } from "../observable/index.js";
 import { SendScheduler, RateLimitingBackoff } from "./SendScheduler.js";
 import {User} from "./User.js";
 import {Account as E2EEAccount} from "./e2ee/Account.js";
+import {DeviceTracker} from "./e2ee/DeviceTracker.js";
 const PICKLE_KEY = "DEFAULT_KEY";
 
 export class Session {
@@ -34,6 +35,11 @@ export class Session {
         this._user = new User(sessionInfo.userId);
         this._olm = olm;
         this._e2eeAccount = null;
+        this._deviceTracker = olm ? new DeviceTracker({
+            storage,
+            getSyncToken: () => this.syncToken,
+            olm,
+        }) : null;
     }
 
     async beforeFirstSync(isNewLogin) {
@@ -152,7 +158,7 @@ export class Session {
         return room;
     }
 
-    writeSync(syncResponse, syncFilterId, txn) {
+    async writeSync(syncResponse, syncFilterId, roomChanges, txn) {
         const changes = {};
         const syncToken = syncResponse.next_batch;
         const deviceOneTimeKeysCount = syncResponse.device_one_time_keys_count;
@@ -166,6 +172,17 @@ export class Session {
             txn.session.set("sync", syncInfo);
             changes.syncInfo = syncInfo;
         }
+        if (this._deviceTracker) {
+            for (const {room, changes} of roomChanges) {
+                if (room.isTrackingMembers && changes.memberChanges?.size) {
+                    await this._deviceTracker.writeMemberChanges(room, changes.memberChanges, txn);
+                }
+            } 
+            const deviceLists = syncResponse.device_lists;
+            if (deviceLists) {
+                await this._deviceTracker.writeDeviceChanges(deviceLists, txn);
+            }
+        }
         return changes;
     }
 

src/matrix/Sync.js

@@ -100,6 +100,7 @@ export class Sync {
                     this._status.set(SyncStatus.Stopped);
                 }
             }
+            if (!this._error) {
                 try {
                     await this._session.afterSyncCompleted();
                 } catch (err) {
@@ -108,6 +109,7 @@ export class Sync {
                 }
             }
         }
+    }
 
     async _syncRequest(syncToken, timeout) {
         let {syncFilterId} = this._session;
@@ -129,11 +131,11 @@ export class Sync {
             storeNames.timelineEvents,
             storeNames.timelineFragments,
             storeNames.pendingEvents,
+            storeNames.userIdentities,
         ]);
         const roomChanges = [];
         let sessionChanges;
         try {
-            sessionChanges = this._session.writeSync(response, syncFilterId, syncTxn);
             // to_device
             // presence
             if (response.rooms) {
@@ -153,6 +155,7 @@ export class Sync {
                 });
                 await Promise.all(promises);
             }
+            sessionChanges = await this._session.writeSync(response, syncFilterId, roomChanges, syncTxn);
         } catch(err) {
             console.warn("aborting syncTxn because of error");
             console.error(err);

src/matrix/e2ee/Account.js

@@ -15,14 +15,12 @@ limitations under the License.
 */
 
 import anotherjson from "../../../lib/another-json/index.js";
+import {SESSION_KEY_PREFIX, OLM_ALGORITHM, MEGOLM_ALGORITHM} from "./common.js";
 
 // use common prefix so it's easy to clear properties that are not e2ee related during session clear
-export const SESSION_KEY_PREFIX = "e2ee:";
 const ACCOUNT_SESSION_KEY = SESSION_KEY_PREFIX + "olmAccount";
 const DEVICE_KEY_FLAG_SESSION_KEY = SESSION_KEY_PREFIX + "areDeviceKeysUploaded";
 const SERVER_OTK_COUNT_SESSION_KEY = SESSION_KEY_PREFIX + "serverOTKCount";
-const OLM_ALGORITHM = "m.olm.v1.curve25519-aes-sha2";
-const MEGOLM_ALGORITHM = "m.megolm.v1.aes-sha2";
 
 export class Account {
     static async load({olm, pickleKey, hsApi, userId, deviceId, txn}) {

src/matrix/e2ee/DeviceTracker.js

@@ -0,0 +1,280 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import anotherjson from "../../../lib/another-json/index.js";
+
+const TRACKING_STATUS_OUTDATED = 0;
+const TRACKING_STATUS_UPTODATE = 1;
+
+const DEVICE_KEYS_SIGNATURE_ALGORITHM = "ed25519";
+
+// map 1 device from /keys/query response to DeviceIdentity
+function deviceKeysAsDeviceIdentity(deviceSection) {
+    const deviceId = deviceSection["device_id"];
+    const userId = deviceSection["user_id"];
+    return {
+        userId,
+        deviceId,
+        ed25519Key: deviceSection.keys?.[`ed25519:${deviceId}`],
+        curve25519Key: deviceSection.keys?.[`curve25519:${deviceId}`],
+        algorithms: deviceSection.algorithms,
+        displayName: deviceSection.unsigned?.device_display_name,
+    };
+}
+
+export class DeviceTracker {
+    constructor({storage, getSyncToken, olm}) {
+        this._storage = storage;
+        this._getSyncToken = getSyncToken;
+        this._identityChangedForRoom = null;
+        this._olmUtil = new olm.Utility();
+    }
+
+    async writeDeviceChanges(deviceLists, txn) {
+        const {userIdentities} = txn;
+        if (Array.isArray(deviceLists.changed) && deviceLists.changed.length) {
+            await Promise.all(deviceLists.changed.map(async userId => {
+                const user = await userIdentities.get(userId);
+                if (user) {
+                    user.deviceTrackingStatus = TRACKING_STATUS_OUTDATED;
+                    userIdentities.set(user);
+                } else {
+                    console.warn("changed device userid not found", userId);
+                }
+            }));
+        }
+    }
+
+    writeMemberChanges(room, memberChanges, txn) {
+        return Promise.all(Array.from(memberChanges.values()).map(async memberChange => {
+            return this._applyMemberChange(memberChange, txn);
+        }));
+    }
+
+    async trackRoom(room) {
+        if (room.isTrackingMembers) {
+            return;
+        }
+        const memberList = await room.loadMemberList();
+        try {
+            const txn = await this._storage.readWriteTxn([
+                this._storage.storeNames.roomSummary,
+                this._storage.storeNames.userIdentities,
+            ]);
+            let isTrackingChanges;
+            try {
+                isTrackingChanges = room.writeIsTrackingMembers(true, txn);
+                const members = Array.from(memberList.members.values());
+                await this._writeJoinedMembers(members, txn);
+            } catch (err) {
+                txn.abort();
+                throw err;
+            }
+            await txn.complete();
+            room.applyIsTrackingMembersChanges(isTrackingChanges);
+        } finally {
+            memberList.release();
+        }
+    }
+
+    async _writeJoinedMembers(members, txn) {
+        await Promise.all(members.map(async member => {
+            if (member.membership === "join") {
+                await this._writeMember(member, txn);
+            }
+        }));
+    }
+
+    async _writeMember(member, txn) {
+        const {userIdentities} = txn;
+        const identity = await userIdentities.get(member.userId);
+        if (!identity) {
+            userIdentities.set({
+                userId: member.userId,
+                roomIds: [member.roomId],
+                deviceTrackingStatus: TRACKING_STATUS_OUTDATED,
+            });
+        } else {
+            if (!identity.roomIds.includes(member.roomId)) {
+                identity.roomIds.push(member.roomId);
+                userIdentities.set(identity);
+            }
+        }
+    }
+
+    async _applyMemberChange(memberChange, txn) {
+        // TODO: depends whether we encrypt for invited users??
+        // add room
+        if (memberChange.previousMembership !== "join" && memberChange.membership === "join") {
+            await this._writeMember(memberChange.member, txn);
+        }
+        // remove room
+        else if (memberChange.previousMembership === "join" && memberChange.membership !== "join") {
+            const {userIdentities} = txn;
+            const identity = await userIdentities.get(memberChange.userId);
+            if (identity) {
+                identity.roomIds = identity.roomIds.filter(roomId => roomId !== memberChange.roomId);
+                // no more encrypted rooms with this user, remove
+                if (identity.roomIds.length === 0) {
+                    userIdentities.remove(identity.userId);
+                } else {
+                    userIdentities.set(identity);
+                }
+            }
+        }
+    }
+
+    async _queryKeys(userIds, hsApi) {
+        // TODO: we need to handle the race here between /sync and /keys/query just like we need to do for the member list ...
+        // there are multiple requests going out for /keys/query though and only one for /members
+
+        const deviceKeyResponse = await hsApi.queryKeys({
+            "timeout": 10000,
+            "device_keys": userIds.reduce((deviceKeysMap, userId) => {
+                deviceKeysMap[userId] = [];
+                return deviceKeysMap;
+            }, {}),
+            "token": this._getSyncToken()
+        }).response();
+
+        const verifiedKeysPerUser = this._filterVerifiedDeviceKeys(deviceKeyResponse["device_keys"]);
+        const flattenedVerifiedKeysPerUser = verifiedKeysPerUser.reduce((all, {verifiedKeys}) => all.concat(verifiedKeys), []);
+        const deviceIdentitiesWithPossibleChangedKeys = flattenedVerifiedKeysPerUser.map(deviceKeysAsDeviceIdentity);
+
+        const txn = await this._storage.readWriteTxn([
+            this._storage.storeNames.userIdentities,
+            this._storage.storeNames.deviceIdentities,
+        ]);
+        let deviceIdentities;
+        try {
+            // check ed25519 key has not changed if we've seen the device before
+            deviceIdentities = await Promise.all(deviceIdentitiesWithPossibleChangedKeys.map(async (deviceIdentity) => {
+                const existingDevice = await txn.deviceIdentities.get(deviceIdentity.userId, deviceIdentity.deviceId);
+                if (!existingDevice || existingDevice.ed25519Key === deviceIdentity.ed25519Key) {
+                    return deviceIdentity;
+                }
+                // ignore devices where the keys have changed
+                return null;
+            }));
+            // filter out nulls
+            deviceIdentities = deviceIdentities.filter(di => !!di);
+            // store devices
+            for (const deviceIdentity of deviceIdentities) {
+                txn.deviceIdentities.set(deviceIdentity);
+            }
+            // mark user identities as up to date
+            await Promise.all(verifiedKeysPerUser.map(async ({userId}) => {
+                const identity = await txn.userIdentities.get(userId);
+                identity.deviceTrackingStatus = TRACKING_STATUS_UPTODATE;
+                txn.userIdentities.set(identity);
+            }));
+        } catch (err) {
+            txn.abort();
+            throw err;
+        }
+        await txn.complete();
+        return deviceIdentities;
+    }
+
+    _filterVerifiedDeviceKeys(keyQueryDeviceKeysResponse) {
+        const verifiedKeys = Object.entries(keyQueryDeviceKeysResponse).map(([userId, keysByDevice]) => {
+            const verifiedEntries = Object.entries(keysByDevice).filter(([deviceId, deviceKeys]) => {
+                const deviceIdOnKeys = deviceKeys["device_id"];
+                const userIdOnKeys = deviceKeys["user_id"];
+                if (userIdOnKeys !== userId) {
+                    return false;
+                }
+                if (deviceIdOnKeys !== deviceId) {
+                    return false;
+                }
+                return this._verifyUserDeviceKeys(deviceKeys);
+            });
+            const verifiedKeys = verifiedEntries.map(([, deviceKeys]) => deviceKeys);
+            return {userId, verifiedKeys};
+        });
+        return verifiedKeys;
+    }
+
+    _verifyUserDeviceKeys(deviceSection) {
+        const deviceId = deviceSection["device_id"];
+        const userId = deviceSection["user_id"];
+        const clone = Object.assign({}, deviceSection);
+        delete clone.unsigned;
+        delete clone.signatures;
+        const canonicalJson = anotherjson.stringify(clone);
+        const key = deviceSection?.keys?.[`${DEVICE_KEYS_SIGNATURE_ALGORITHM}:${deviceId}`];
+        const signature = deviceSection?.signatures?.[userId]?.[`${DEVICE_KEYS_SIGNATURE_ALGORITHM}:${deviceId}`];
+        try {
+            if (!signature) {
+                throw new Error("no signature");
+            }
+            // throws when signature is invalid
+            this._olmUtil.ed25519_verify(key, canonicalJson, signature);
+            return true;
+        } catch (err) {
+            console.warn("Invalid device signature, ignoring device.", key, canonicalJson, signature, err);
+            return false;
+        }
+    }
+
+    /**
+     * Gives all the device identities for a room that is already tracked.
+     * Assumes room is already tracked. Call `trackRoom` first if unsure.
+     * @param  {String} roomId [description]
+     * @return {[type]}        [description]
+     */
+    async deviceIdentitiesForTrackedRoom(roomId, hsApi) {
+        let identities;
+        const txn = await this._storage.readTxn([
+            this._storage.storeNames.roomMembers,
+            this._storage.storeNames.userIdentities,
+        ]);
+
+        // because we don't have multiEntry support in IE11, we get a set of userIds that is pretty close to what we
+        // need as a good first filter (given that non-join memberships will be in there). After fetching the identities,
+        // we check which ones have the roomId for the room we're looking at.
+        
+        // So, this will also contain non-joined memberships
+        const userIds = await txn.roomMembers.getAllUserIds(roomId);
+        const allMemberIdentities = await Promise.all(userIds.map(userId => txn.userIdentities.get(userId)));
+        identities = allMemberIdentities.filter(identity => {
+            // identity will be missing for any userIds that don't have 
+            // membership join in any of your encrypted rooms
+            return identity && identity.roomIds.includes(roomId);
+        });
+        const upToDateIdentities = identities.filter(i => i.deviceTrackingStatus === TRACKING_STATUS_UPTODATE);
+        const outdatedIdentities = identities.filter(i => i.deviceTrackingStatus === TRACKING_STATUS_OUTDATED);
+        let queriedDevices;
+        if (outdatedIdentities.length) {
+            // TODO: ignore the race between /sync and /keys/query for now,
+            // where users could get marked as outdated or added/removed from the room while
+            // querying keys
+            queriedDevices = await this._queryKeys(outdatedIdentities.map(i => i.userId), hsApi);
+        }
+
+        const deviceTxn = await this._storage.readTxn([
+            this._storage.storeNames.deviceIdentities,
+        ]);
+        const devicesPerUser = await Promise.all(upToDateIdentities.map(identity => {
+            return deviceTxn.deviceIdentities.getAllForUserId(identity.userId);
+        }));
+        let flattenedDevices = devicesPerUser.reduce((all, devicesForUser) => all.concat(devicesForUser), []);
+        if (queriedDevices && queriedDevices.length) {
+            flattenedDevices = flattenedDevices.concat(queriedDevices);
+        }
+        return flattenedDevices;
+    }
+}

src/matrix/e2ee/common.js

@@ -0,0 +1,20 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// use common prefix so it's easy to clear properties that are not e2ee related during session clear
+export const SESSION_KEY_PREFIX = "e2ee:";
+export const OLM_ALGORITHM = "m.olm.v1.curve25519-aes-sha2";
+export const MEGOLM_ALGORITHM = "m.megolm.v1.aes-sha2";

src/matrix/net/HomeServerApi.js

@@ -164,6 +164,10 @@ export class HomeServerApi {
         return this._post("/keys/upload", null, payload, options);
     }
 
+    queryKeys(queryRequest, options = null) {
+        return this._post("/keys/query", null, queryRequest, options);
+    }
+
     get mediaRepository() {
         return this._mediaRepository;
     }

src/matrix/room/Room.js

@@ -40,6 +40,7 @@ export class Room extends EventEmitter {
         this._timeline = null;
         this._user = user;
         this._changedMembersDuringSync = null;
+        this._memberList = null;
 	}
 
     /** @package */
@@ -50,7 +51,7 @@ export class Room extends EventEmitter {
             membership,
             isInitialSync, isTimelineOpen,
             txn);
-		const {entries, newLiveKey, changedMembers} = await this._syncWriter.writeSync(roomResponse, txn);
+		const {entries, newLiveKey, memberChanges} = await this._syncWriter.writeSync(roomResponse, txn);
         // fetch new members while we have txn open,
         // but don't make any in-memory changes yet
         let heroChanges;
@@ -59,7 +60,7 @@ export class Room extends EventEmitter {
             if (!this._heroes) {
                 this._heroes = new Heroes(this._roomId);
             }
-            heroChanges = await this._heroes.calculateChanges(summaryChanges.heroes, changedMembers, txn);
+            heroChanges = await this._heroes.calculateChanges(summaryChanges.heroes, memberChanges, txn);
         }
         let removedPendingEvents;
         if (roomResponse.timeline && roomResponse.timeline.events) {
@@ -70,22 +71,22 @@ export class Room extends EventEmitter {
             newTimelineEntries: entries,
             newLiveKey,
             removedPendingEvents,
-            changedMembers,
+            memberChanges,
             heroChanges
         };
     }
 
     /** @package */
-    afterSync({summaryChanges, newTimelineEntries, newLiveKey, removedPendingEvents, changedMembers, heroChanges}) {
+    afterSync({summaryChanges, newTimelineEntries, newLiveKey, removedPendingEvents, memberChanges, heroChanges}) {
         this._syncWriter.afterSync(newLiveKey);
-        if (changedMembers.length) {
+        if (memberChanges.size) {
             if (this._changedMembersDuringSync) {
-                for (const member of changedMembers) {
+                for (const [userId, memberChange] of memberChanges.entries()) {
-                    this._changedMembersDuringSync.set(member.userId, member);
+                    this._changedMembersDuringSync.set(userId, memberChange.member);
                 }
             }
             if (this._memberList) {
-                this._memberList.afterSync(changedMembers);
+                this._memberList.afterSync(memberChanges);
             }
         }
         let emitChange = false;
@@ -144,6 +145,7 @@ export class Room extends EventEmitter {
     /** @public */
     async loadMemberList() {
         if (this._memberList) {
+            // TODO: also await fetchOrLoadMembers promise here
             this._memberList.retain();
             return this._memberList;
         } else {
@@ -256,6 +258,14 @@ export class Room extends EventEmitter {
         return !!(tags && tags['m.lowpriority']);
     }
 
+    get isEncrypted() {
+        return !!this._summary.encryption;
+    }
+
+    get isTrackingMembers() {
+        return this._summary.isTrackingMembers;
+    }
+
     async _getLastEventId() {
         const lastKey = this._syncWriter.lastMessageKey;
         if (lastKey) {
@@ -322,5 +332,15 @@ export class Room extends EventEmitter {
     get mediaRepository() {
         return this._hsApi.mediaRepository;
     }
+
+    /** @package */
+    writeIsTrackingMembers(value, txn) {
+        return this._summary.writeIsTrackingMembers(value, txn);
+    }
+
+    /** @package */
+    applyIsTrackingMembersChanges(changes) {
+        this._summary.applyChanges(changes);
+    }
 }
 

src/matrix/room/RoomSummary.js

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import {MEGOLM_ALGORITHM} from "../e2ee/common.js";
+
 function applySyncResponse(data, roomResponse, membership, isInitialSync, isTimelineOpen, ownUserId) {
     if (roomResponse.summary) {
         data = updateSummary(data, roomResponse.summary);
@@ -68,9 +70,10 @@ function processRoomAccountData(data, event) {
 
 function processStateEvent(data, event) {
     if (event.type === "m.room.encryption") {
-        if (!data.isEncrypted) {
+        const algorithm = event.content?.algorithm;
+        if (!data.encryption && algorithm === MEGOLM_ALGORITHM) {
             data = data.cloneIfNeeded();
-            data.isEncrypted = true;
+            data.encryption = event.content;
         }
     } else if (event.type === "m.room.name") {
         const newName = event.content?.name;
@@ -113,7 +116,9 @@ function updateSummary(data, summary) {
     const heroes = summary["m.heroes"];
     const joinCount = summary["m.joined_member_count"];
     const inviteCount = summary["m.invited_member_count"];
-
+    // TODO: we could easily calculate if all members are available here and set hasFetchedMembers?
+    // so we can avoid calling /members...
+    // we'd need to do a count query in the roomMembers store though ...
     if (heroes && Array.isArray(heroes)) {
         data = data.cloneIfNeeded();
         data.heroes = heroes;
@@ -136,7 +141,7 @@ class SummaryData {
         this.lastMessageBody = copy ? copy.lastMessageBody : null;
         this.lastMessageTimestamp = copy ? copy.lastMessageTimestamp : null;
         this.isUnread = copy ? copy.isUnread : false;
-        this.isEncrypted = copy ? copy.isEncrypted : false;
+        this.encryption = copy ? copy.encryption : null;
         this.isDirectMessage = copy ? copy.isDirectMessage : false;
         this.membership = copy ? copy.membership : null;
         this.inviteCount = copy ? copy.inviteCount : 0;
@@ -144,6 +149,7 @@ class SummaryData {
         this.heroes = copy ? copy.heroes : null;
         this.canonicalAlias = copy ? copy.canonicalAlias : null;
         this.hasFetchedMembers = copy ? copy.hasFetchedMembers : false;
+        this.isTrackingMembers = copy ? copy.isTrackingMembers : false;
         this.lastPaginationToken = copy ? copy.lastPaginationToken : null;
         this.avatarUrl = copy ? copy.avatarUrl : null;
         this.notificationCount = copy ? copy.notificationCount : 0;
@@ -190,6 +196,11 @@ export class RoomSummary {
         return this._data.heroes;
     }
 
+    get encryption() {
+        return this._data.encryption;
+    }
+
+    // whether the room name should be determined with Heroes
     get needsHeroes() {
         return needsHeroes(this._data);
     }
@@ -230,6 +241,10 @@ export class RoomSummary {
         return this._data.hasFetchedMembers;
     }
 
+    get isTrackingMembers() {
+        return this._data.isTrackingMembers;
+    }
+
     get lastPaginationToken() {
         return this._data.lastPaginationToken;
     }
@@ -254,6 +269,13 @@ export class RoomSummary {
         return data;
     }
 
+    writeIsTrackingMembers(value, txn) {
+        const data = new SummaryData(this._data);
+        data.isTrackingMembers = value;
+        txn.roomSummary.set(data.serialize());
+        return data;
+    }
+
 	writeSync(roomResponse, membership, isInitialSync, isTimelineOpen, txn) {
         // clear cloned flag, so cloneIfNeeded makes a copy and
         // this._data is not modified if any field is changed.

src/matrix/room/common.js

@@ -0,0 +1,21 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export function getPrevContentFromStateEvent(event) {
+    // where to look for prev_content is a bit of a mess,
+    // see https://matrix.to/#/!NasysSDfxKxZBzJJoE:matrix.org/$DvrAbZJiILkOmOIuRsNoHmh2v7UO5CWp_rYhlGk34fQ?via=matrix.org&via=pixie.town&via=amorgan.xyz
+    return event.unsigned?.prev_content || event.prev_content;
+}

src/matrix/room/members/Heroes.js

@@ -42,11 +42,11 @@ export class Heroes {
 
     /**
      * @param  {string[]} newHeroes      array of user ids
-     * @param  {RoomMember[]} changedMembers array of changed members in this sync
+     * @param  {Map<string, MemberChange>} memberChanges map of changed memberships
      * @param  {Transaction} txn
      * @return {Promise}
      */
-    async calculateChanges(newHeroes, changedMembers, txn) {
+    async calculateChanges(newHeroes, memberChanges, txn) {
         const updatedHeroMembers = new Map();
         const removedUserIds = [];
         // remove non-present members
@@ -56,9 +56,9 @@ export class Heroes {
             }
         }
         // update heroes with synced member changes
-        for (const member of changedMembers) {
+        for (const [userId, memberChange] of memberChanges.entries()) {
-            if (this._members.has(member.userId) || newHeroes.indexOf(member.userId) !== -1) {
+            if (this._members.has(userId) || newHeroes.indexOf(userId) !== -1) {
-                updatedHeroMembers.set(member.userId, member);
+                updatedHeroMembers.set(userId, memberChange.member);
             }
         }
         // load member for new heroes from storage

src/matrix/room/members/MemberList.js

@@ -26,9 +26,9 @@ export class MemberList {
         this._retentionCount = 1;
     }
 
-    afterSync(updatedMembers) {
+    afterSync(memberChanges) {
-        for (const member of updatedMembers) {
+        for (const [userId, memberChange] of memberChanges.entries()) {
-            this._members.add(member.userId, member);
+            this._members.add(userId, memberChange.member);
         }
     }
 

src/matrix/room/members/RoomMember.js

@@ -1,5 +1,4 @@
 /*
-Copyright 2020 Bruno Windels <bruno@windels.cloud>
 Copyright 2020 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
@@ -15,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import {getPrevContentFromStateEvent} from "../common.js";
+
 export const EVENT_TYPE = "m.room.member";
 
 export class RoomMember {
@@ -28,7 +29,7 @@ export class RoomMember {
             return;
         }
         const content = memberEvent.content;
-        const prevContent = memberEvent.unsigned?.prev_content;
+        const prevContent = getPrevContentFromStateEvent(memberEvent);
         const membership = content?.membership;
         // fall back to prev_content for these as synapse doesn't (always?)
         // put them on content for "leave" memberships
@@ -45,7 +46,7 @@ export class RoomMember {
         if (typeof userId !== "string") {
             return;
         }
-        const content = memberEvent.unsigned?.prev_content
+        const content = getPrevContentFromStateEvent(memberEvent);
         return this._validateAndCreateMember(roomId, userId,
             content?.membership,
             content?.displayname,
@@ -66,6 +67,10 @@ export class RoomMember {
         });
     }
 
+    get membership() {
+        return this._data.membership;
+    }
+
     /**
      * @return {String?} the display name, if any
      */
@@ -99,3 +104,34 @@ export class RoomMember {
         return this._data;
     }
 }
+
+export class MemberChange {
+    constructor(roomId, memberEvent) {
+        this._roomId = roomId;
+        this._memberEvent = memberEvent;
+        this._member = null;
+    }
+
+    get member() {
+        if (!this._member) {
+            this._member = RoomMember.fromMemberEvent(this._roomId, this._memberEvent);
+        }
+        return this._member;
+    }
+
+    get roomId() {
+        return this._roomId;
+    }
+
+    get userId() {
+        return this._memberEvent.state_key;
+    }
+
+    get previousMembership() {
+        return getPrevContentFromStateEvent(this._memberEvent)?.membership;
+    }
+
+    get membership() {
+        return this._memberEvent.content?.membership;
+    }
+}

src/matrix/room/members/load.js

@@ -31,7 +31,7 @@ async function fetchMembers({summary, roomId, hsApi, storage, setChangedMembersM
     const changedMembersDuringSync = new Map();
     setChangedMembersMap(changedMembersDuringSync);
     
-    const memberResponse = await hsApi.members(roomId, {at: summary.lastPaginationToken}).response;
+    const memberResponse = await hsApi.members(roomId, {at: summary.lastPaginationToken}).response();
 
     const txn = await storage.readWriteTxn([
         storage.storeNames.roomSummary,

src/matrix/room/timeline/entries/EventEntry.js

@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import {BaseEntry} from "./BaseEntry.js";
+import {getPrevContentFromStateEvent} from "../../common.js";
 
 export class EventEntry extends BaseEntry {
     constructor(eventEntry, fragmentIdComparer) {
@@ -35,7 +36,7 @@ export class EventEntry extends BaseEntry {
     }
 
     get prevContent() {
-        return this._eventEntry.event.unsigned?.prev_content;
+        return getPrevContentFromStateEvent(this._eventEntry.event);
     }
 
     get eventType() {

src/matrix/room/timeline/persistence/SyncWriter.js

@@ -18,7 +18,7 @@ import {EventKey} from "../EventKey.js";
 import {EventEntry} from "../entries/EventEntry.js";
 import {FragmentBoundaryEntry} from "../entries/FragmentBoundaryEntry.js";
 import {createEventEntry} from "./common.js";
-import {RoomMember, EVENT_TYPE as MEMBER_EVENT_TYPE} from "../../members/RoomMember.js";
+import {MemberChange, RoomMember, EVENT_TYPE as MEMBER_EVENT_TYPE} from "../../members/RoomMember.js";
 
 // Synapse bug? where the m.room.create event appears twice in sync response
 // when first syncing the room
@@ -102,13 +102,13 @@ export class SyncWriter {
         if (event.type === MEMBER_EVENT_TYPE) {
             const userId = event.state_key;
             if (userId) {
-                const member = RoomMember.fromMemberEvent(this._roomId, event);
+                const memberChange = new MemberChange(this._roomId, event);
-                if (member) {
+                if (memberChange.member) {
                     // as this is sync, we can just replace the member
                     // if it is there already
-                    txn.roomMembers.set(member.serialize());
+                    txn.roomMembers.set(memberChange.member.serialize());
+                    return memberChange;
                 }
-                return member;
             }
         } else {
             txn.roomState.set(this._roomId, event);
@@ -116,22 +116,22 @@ export class SyncWriter {
     }
 
     _writeStateEvents(roomResponse, txn) {
-        const changedMembers = [];
+        const memberChanges = new Map();
         // persist state
         const {state} = roomResponse;
         if (Array.isArray(state?.events)) {
             for (const event of state.events) {
-                const member = this._writeStateEvent(event, txn);
+                const memberChange = this._writeStateEvent(event, txn);
-                if (member) {
+                if (memberChange) {
-                    changedMembers.push(member);
+                    memberChanges.set(memberChange.userId, memberChange);
                 }
             }
         }
-        return changedMembers;
+        return memberChanges;
     }
 
     async _writeTimeline(entries, timeline, currentKey, txn) {
-        const changedMembers = [];
+        const memberChanges = new Map();
         if (timeline.events) {
             const events = deduplicateEvents(timeline.events);
             for(const event of events) {
@@ -148,14 +148,14 @@ export class SyncWriter {
                 
                 // process live state events first, so new member info is available
                 if (typeof event.state_key === "string") {
-                    const member = this._writeStateEvent(event, txn);
+                    const memberChange = this._writeStateEvent(event, txn);
-                    if (member) {
+                    if (memberChange) {
-                        changedMembers.push(member);
+                        memberChanges.set(memberChange.userId, memberChange);
                     }
                 }
             }
         }
-        return {currentKey, changedMembers};
+        return {currentKey, memberChanges};
     }
 
     async _findMemberData(userId, events, txn) {
@@ -198,12 +198,14 @@ export class SyncWriter {
         }
         // important this happens before _writeTimeline so
         // members are available in the transaction
-        const changedMembers = this._writeStateEvents(roomResponse, txn);
+        const memberChanges = this._writeStateEvents(roomResponse, txn);
         const timelineResult = await this._writeTimeline(entries, timeline, currentKey, txn);
         currentKey = timelineResult.currentKey;
-        changedMembers.push(...timelineResult.changedMembers);
+        // merge member changes from state and timeline, giving precedence to the latter
-
+        for (const [userId, memberChange] of timelineResult.memberChanges.entries()) {
-        return {entries, newLiveKey: currentKey, changedMembers};
+            memberChanges.set(userId, memberChange);
+        }
+        return {entries, newLiveKey: currentKey, memberChanges};
     }
 
     afterSync(newLiveKey) {

src/matrix/storage/common.js

@@ -22,6 +22,8 @@ export const STORE_NAMES = Object.freeze([
     "timelineEvents",
     "timelineFragments",
     "pendingEvents",
+    "userIdentities",
+    "deviceIdentities",
 ]);
 
 export const STORE_MAP = Object.freeze(STORE_NAMES.reduce((nameMap, name) => {

src/matrix/storage/idb/QueryTarget.js

@@ -105,6 +105,13 @@ export class QueryTarget {
         return maxKey;
     }
 
+    async iterateKeys(range, callback) {
+        const cursor = this._target.openKeyCursor(range, "next");
+        await iterateCursor(cursor, (_, key) => {
+            return {done: callback(key)};
+        });
+    }
+
     /**
      * Checks if a given set of keys exist.
      * Calls `callback(key, found)` for each key in `keys`, in key sorting order (or reversed if backwards=true).

src/matrix/storage/idb/Transaction.js

@@ -24,6 +24,8 @@ import {RoomStateStore} from "./stores/RoomStateStore.js";
 import {RoomMemberStore} from "./stores/RoomMemberStore.js";
 import {TimelineFragmentStore} from "./stores/TimelineFragmentStore.js";
 import {PendingEventStore} from "./stores/PendingEventStore.js";
+import {UserIdentityStore} from "./stores/UserIdentityStore.js";
+import {DeviceIdentityStore} from "./stores/DeviceIdentityStore.js";
 
 export class Transaction {
     constructor(txn, allowedStoreNames) {
@@ -81,6 +83,14 @@ export class Transaction {
         return this._store("pendingEvents", idbStore => new PendingEventStore(idbStore));
     }
 
+    get userIdentities() {
+        return this._store("userIdentities", idbStore => new UserIdentityStore(idbStore));
+    }
+
+    get deviceIdentities() {
+        return this._store("deviceIdentities", idbStore => new DeviceIdentityStore(idbStore));
+    }
+    
     complete() {
         return txnAsPromise(this._txn);
     }

src/matrix/storage/idb/schema.js

@@ -9,6 +9,7 @@ export const schema = [
     createInitialStores,
     createMemberStore,
     migrateSession,
+    createIdentityStores,
 ];
 // TODO: how to deal with git merge conflicts of this array?
 
@@ -46,7 +47,7 @@ async function createMemberStore(db, txn) {
         }
     });
 }
-
+//v3
 async function migrateSession(db, txn) {
     const session = txn.objectStore("session");
     try {
@@ -64,3 +65,8 @@ async function migrateSession(db, txn) {
         console.error("could not migrate session", err.stack);
     }
 }
+//v4
+function createIdentityStores(db) {
+    db.createObjectStore("userIdentities", {keyPath: "userId"});
+    db.createObjectStore("deviceIdentities", {keyPath: "key"});
+}

src/matrix/storage/idb/stores/DeviceIdentityStore.js

@@ -0,0 +1,41 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+function encodeKey(userId, deviceId) {
+    return `${userId}|${deviceId}`;
+}
+
+export class DeviceIdentityStore {
+    constructor(store) {
+        this._store = store;
+    }
+
+    getAllForUserId(userId) {
+        const range = IDBKeyRange.lowerBound(encodeKey(userId, ""));
+        return this._store.selectWhile(range, device => {
+            return device.userId === userId;
+        });
+    }
+
+    get(userId, deviceId) {
+        return this._store.get(encodeKey(userId, deviceId));
+    }
+
+    set(deviceIdentity) {
+        deviceIdentity.key = encodeKey(deviceIdentity.userId, deviceIdentity.deviceId);
+        return this._store.put(deviceIdentity);
+    }
+}

src/matrix/storage/idb/stores/RoomMemberStore.js

@@ -19,6 +19,11 @@ function encodeKey(roomId, userId) {
     return `${roomId}|${userId}`;
 }
 
+function decodeKey(key) {
+    const [roomId, userId] = key.split("|");
+    return {roomId, userId};
+}
+
 // no historical members
 export class RoomMemberStore {
     constructor(roomMembersStore) {
@@ -40,4 +45,19 @@ export class RoomMemberStore {
             return member.roomId === roomId;
         });
     }
+
+    async getAllUserIds(roomId) {
+        const userIds = [];
+        const range = IDBKeyRange.lowerBound(encodeKey(roomId, ""));
+        await this._roomMembersStore.iterateKeys(range, key => {
+            const decodedKey = decodeKey(key);
+            // prevent running into the next room
+            if (decodedKey.roomId === roomId) {
+                userIds.push(decodedKey.userId);
+                return false;   // fetch more
+            }
+            return true; // done
+        });
+        return userIds;
+    }
 }

src/matrix/storage/idb/stores/UserIdentityStore.js

@@ -0,0 +1,33 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export class UserIdentityStore {
+    constructor(store) {
+        this._store = store;
+    }
+
+    get(userId) {
+        return this._store.get(userId);
+    }
+
+    set(userIdentity) {
+        this._store.put(userIdentity);
+    }
+
+    remove(userId) {
+        return this._store.delete(userId);
+    }
+}

src/observable/map/ObservableMap.js

@@ -70,6 +70,10 @@ export class ObservableMap extends BaseObservableMap {
     [Symbol.iterator]() {
         return this._values.entries();
     }
+
+    values() {
+        return this._values.values();
+    }
 }
 
 export function tests() {