create key share operations for invitees when history visibility=invited

src/matrix/e2ee/RoomEncryption.js

@@ -19,13 +19,23 @@ import {groupEventsBySession} from "./megolm/decryption/utils";
 import {mergeMap} from "../../utils/mergeMap";
 import {groupBy} from "../../utils/groupBy";
 import {makeTxnId} from "../common.js";
+import {iterateResponseStateEvents} from "../room/common";
 
 const ENCRYPTED_TYPE = "m.room.encrypted";
+const ROOM_HISTORY_VISIBILITY_TYPE = "m.room.history_visibility";
 // how often ensureMessageKeyIsShared can check if it needs to
 // create a new outbound session
 // note that encrypt could still create a new session
 const MIN_PRESHARE_INTERVAL = 60 * 1000; // 1min
 
+// Use enum when converting to TS
+const HistoryVisibility = Object.freeze({
+    Joined: "joined",
+    Invited: "invited",
+    WorldReadable: "world_readable",
+    Shared: "shared",
+});
+
 // TODO: this class is a good candidate for splitting up into encryption and decryption, there doesn't seem to be much overlap
 export class RoomEncryption {
     constructor({room, deviceTracker, olmEncryption, megolmEncryption, megolmDecryption, encryptionParams, storage, keyBackup, notifyMissingMegolmSession, clock}) {
@@ -45,6 +55,7 @@ export class RoomEncryption {
         this._isFlushingRoomKeyShares = false;
         this._lastKeyPreShareTime = null;
         this._keySharePromise = null;
+        this._historyVisibility = undefined;
         this._disposed = false;
     }
 
@@ -77,7 +88,13 @@ export class RoomEncryption {
         this._senderDeviceCache = new Map();    // purge the sender device cache
     }
 
-    async writeMemberChanges(memberChanges, txn, log) {
+    async writeSync(roomResponse, memberChanges, txn, log) {
+        let historyVisibility = this._historyVisibility;
+        iterateResponseStateEvents(roomResponse, event => {
+            if(event.state_key === "" && event.type === ROOM_HISTORY_VISIBILITY_TYPE) {
+                historyVisibility = event?.content?.history_visibility;
+            }
+        });
         let shouldFlush = false;
         const memberChangesArray = Array.from(memberChanges.values());
         // this also clears our session if we leave the room ourselves
@@ -89,10 +106,35 @@ export class RoomEncryption {
             this._megolmEncryption.discardOutboundSession(this._room.id, txn);
         }
         if (memberChangesArray.some(m => m.hasJoined)) {
-            shouldFlush = await this._addShareRoomKeyOperationForNewMembers(memberChangesArray, txn, log);
+            const userIds = memberChangesArray.filter(m => m.hasJoined).map(m => m.userId);
+            shouldFlush = await this._addShareRoomKeyOperationForMembers(userIds, txn, log)
+                            || shouldFlush;
         }
+        if (memberChangesArray.some(m => m.wasInvited)) {
+            historyVisibility = await this._loadHistoryVisibilityIfNeeded(historyVisibility, txn);
+            if (historyVisibility === HistoryVisibility.Invited) {
+                const userIds = memberChangesArray.filter(m => m.wasInvited).map(m => m.userId);
+                shouldFlush = await this._addShareRoomKeyOperationForMembers(userIds, txn, log)
+                                || shouldFlush;
+            }
+        }
+        
         await this._deviceTracker.writeMemberChanges(this._room, memberChanges, txn);
-        return shouldFlush;
+        return {shouldFlush, historyVisibility};
+    }
+
+    afterSync({historyVisibility}) {
+        this._historyVisibility = historyVisibility;
+    }
+
+    async _loadHistoryVisibilityIfNeeded(historyVisibility, txn) {
+        if (!historyVisibility) {
+            const visibilityEntry = await txn.roomState.get(this.id, ROOM_HISTORY_VISIBILITY_TYPE, "");
+            if (visibilityEntry) {
+                return event?.content?.history_visibility;
+            }
+        }
+        return historyVisibility;
     }
 
     async prepareDecryptAll(events, newKeys, source, txn) {
@@ -288,8 +330,7 @@ export class RoomEncryption {
         await this._processShareRoomKeyOperation(operation, hsApi, log);
     }
 
-    async _addShareRoomKeyOperationForNewMembers(memberChangesArray, txn, log) {
-        const userIds = memberChangesArray.filter(m => m.hasJoined).map(m => m.userId);
+    async _addShareRoomKeyOperationForMembers(userIds, txn, log) {
         const roomKeyMessage = await this._megolmEncryption.createRoomKeyMessage(
             this._room.id, txn);
         if (roomKeyMessage) {

src/matrix/room/Room.js

@@ -139,11 +139,11 @@ export class Room extends BaseRoom {
         }
         log.set("newEntries", newEntries.length);
         log.set("updatedEntries", updatedEntries.length);
-        let shouldFlushKeyShares = false;
+        let encryptionChanges;
         // pass member changes to device tracker
-        if (roomEncryption && this.isTrackingMembers && memberChanges?.size) {
-            shouldFlushKeyShares = await roomEncryption.writeMemberChanges(memberChanges, txn, log);
-            log.set("shouldFlushKeyShares", shouldFlushKeyShares);
+        if (roomEncryption) {
+            encryptionChanges = await roomEncryption.writeSync(roomResponse, memberChanges, txn, log);
+            log.set("shouldFlushKeyShares", encryptionChanges.shouldFlush);
         }
         const allEntries = newEntries.concat(updatedEntries);
         // also apply (decrypted) timeline entries to the summary changes
@@ -188,7 +188,7 @@ export class Room extends BaseRoom {
             memberChanges,
             heroChanges,
             powerLevelsEvent,
-            shouldFlushKeyShares,
+            encryptionChanges,
         };
     }
 
@@ -201,11 +201,14 @@ export class Room extends BaseRoom {
         const {
             summaryChanges, newEntries, updatedEntries, newLiveKey,
             removedPendingEvents, memberChanges, powerLevelsEvent,
-            heroChanges, roomEncryption
+            heroChanges, roomEncryption, encryptionChanges
         } = changes;
         log.set("id", this.id);
         this._syncWriter.afterSync(newLiveKey);
         this._setEncryption(roomEncryption);
+        if (this._roomEncryption) {
+            this._roomEncryption.afterSync(encryptionChanges);
+        }
         if (memberChanges.size) {
             if (this._changedMembersDuringSync) {
                 for (const [userId, memberChange] of memberChanges.entries()) {
@@ -288,8 +291,8 @@ export class Room extends BaseRoom {
         }
     }
 
-    needsAfterSyncCompleted({shouldFlushKeyShares}) {
-        return shouldFlushKeyShares;
+    needsAfterSyncCompleted({encryptionChanges}) {
+        return encryptionChanges?.shouldFlush;
     }
 
     /**

src/matrix/room/common.ts

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import type {StateEvent} from "../storage/types";
+
 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
@@ -40,3 +42,72 @@ export enum RoomType {
     Private,
     Public
 }
+
+type RoomResponse = {
+    state?: {
+        events?: Array<StateEvent>
+    },
+    timeline?: {
+        events?: Array<StateEvent>
+    }
+}
+
+/** iterates over any state events in a sync room response, in the order that they should be applied (from older to younger events) */
+export function iterateResponseStateEvents(roomResponse: RoomResponse, callback: (StateEvent) => void) {
+    // first iterate over state events, they precede the timeline
+    const stateEvents = roomResponse.state?.events;
+    if (stateEvents) {
+        for (let i = 0; i < stateEvents.length; i++) {
+            callback(stateEvents[i]);
+        }
+    }
+    // now see if there are any state events within the timeline
+    let timelineEvents = roomResponse.timeline?.events;
+    if (timelineEvents) {
+        for (let i = 0; i < timelineEvents.length; i++) {
+            const event = timelineEvents[i];
+            if (typeof event.state_key === "string") {
+                callback(event);
+            }
+        }
+    }
+}
+
+export function tests() {
+    return {
+        "test iterateResponseStateEvents with both state and timeline sections": assert => {
+            const roomResponse = {
+                state: {
+                    events: [
+                        {type: "m.room.member", state_key: "1"},
+                        {type: "m.room.member", state_key: "2", content: {a: 1}},
+                    ]
+                },
+                timeline: {
+                    events: [
+                        {type: "m.room.message"},
+                        {type: "m.room.member", state_key: "3"},
+                        {type: "m.room.message"},
+                        {type: "m.room.member", state_key: "2", content: {a: 2}},
+                    ]
+                }
+            } as unknown as RoomResponse;
+            const expectedStateKeys = ["1", "2", "3", "2"];
+            const expectedAForMember2 = [1, 2];
+            iterateResponseStateEvents(roomResponse, event => {
+                assert.strictEqual(event.type, "m.room.member");
+                assert.strictEqual(expectedStateKeys.shift(), event.state_key);
+                if (event.state_key === "2") {
+                    assert.strictEqual(expectedAForMember2.shift(), event.content.a);
+                }
+            });
+            assert.strictEqual(expectedStateKeys.length, 0);
+            assert.strictEqual(expectedAForMember2.length, 0);
+        },
+        "test iterateResponseStateEvents with empty response": assert => {
+            iterateResponseStateEvents({}, () => {
+                assert.fail("no events expected");
+            });
+        }
+    }
+}

src/matrix/room/members/RoomMember.js

@@ -137,6 +137,10 @@ export class MemberChange {
         return this.member.membership;
     }
 
+    get wasInvited() {
+        return this.previousMembership === "invite" && this.membership !== "invite";
+    }
+
     get hasLeft() {
         return this.previousMembership === "join" && this.membership !== "join";
     }