remove room from all user identities when leaving

and delete identity as well as all device identities if no rooms left

src/matrix/e2ee/DeviceTracker.js

@@ -121,24 +121,38 @@ export class DeviceTracker {
         }
     }
 
+    async _removeRoomFromUserIdentity(roomId, userId, txn) {
+        const {userIdentities, deviceIdentities} = txn;
+        const identity = await userIdentities.get(userId);
+        if (identity) {
+            identity.roomIds = identity.roomIds.filter(id => id !== roomId);
+            // no more encrypted rooms with this user, remove
+            if (identity.roomIds.length === 0) {
+                userIdentities.remove(userId);
+                deviceIdentities.removeAllForUser(userId);
+            } else {
+                userIdentities.set(identity);
+            }
+        }
+    }
+
     async _applyMemberChange(memberChange, txn) {
         // TODO: depends whether we encrypt for invited users??
         // add room
-        if (memberChange.previousMembership !== "join" && memberChange.membership === "join") {
+        if (memberChange.hasJoined) {
             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);
-                }
+        else if (memberChange.hasLeft) {
+            const {roomId} = memberChange;
+            // if we left the room, remove room from all user identities in the room
+            if (memberChange.userId === this._ownUserId) {
+                const userIds = await txn.roomMembers.getAllUserIds(roomId);
+                await Promise.all(userIds.map(userId => {
+                    return this._removeRoomFromUserIdentity(roomId, userId, txn);
+                }));
+            } else {
+                await this._removeRoomFromUserIdentity(roomId, memberChange.userId, txn);
             }
         }
     }

src/matrix/e2ee/RoomEncryption.js

@@ -85,6 +85,7 @@ export class RoomEncryption {
     async writeMemberChanges(memberChanges, txn, log) {
         let shouldFlush = false;
         const memberChangesArray = Array.from(memberChanges.values());
+        // this also clears our session if we leave the room ourselves
         if (memberChangesArray.some(m => m.hasLeft)) {
             log.log({
                 l: "discardOutboundSession",

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

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import {MAX_UNICODE, MIN_UNICODE} from "./common.js";
+
 function encodeKey(userId, deviceId) {
     return `${userId}|${deviceId}`;
 }
@@ -66,4 +68,11 @@ export class DeviceIdentityStore {
     remove(userId, deviceId) {
         this._store.delete(encodeKey(userId, deviceId));
     }
+
+    removeAllForUser(userId) {
+        // exclude both keys as they are theoretical min and max,
+        // but we should't have a match for just the room id, or room id with max
+        const range = IDBKeyRange.bound(encodeKey(userId, MIN_UNICODE), encodeKey(userId, MAX_UNICODE), true, true);
+        this._store.delete(range);
+    }
 }

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

@@ -1,5 +1,6 @@
 /*
 Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2021 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.
@@ -14,7 +15,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-const MAX_UNICODE = "\u{10FFFF}";
+import {MAX_UNICODE} from "./common.js";
 
 export class RoomStateStore {
 	constructor(idbStore) {

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

@@ -0,0 +1,18 @@
+/*
+Copyright 2021 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 const MIN_UNICODE = "\u{0}";
+export const MAX_UNICODE = "\u{10FFFF}";