v30.0.0

Co-authored-by: Andy Balaam <andy.balaam@matrix.org>

.github/workflows/cypress.yml

@@ -20,7 +20,7 @@ jobs:
         # from creeping in. They take a long time to run and consume 4 concurrent runners.
         if: github.event.workflow_run.event == 'merge_group'
 
-        uses: matrix-org/matrix-react-sdk/.github/workflows/cypress.yaml@66854039a33ed6cfe1fc635ff2daa8bb261c0b56
+        uses: matrix-org/matrix-react-sdk/.github/workflows/cypress.yaml@v3.83.0-rc.1
         permissions:
             actions: read
             issues: read

.github/workflows/downstream-artifacts.yml

@@ -20,7 +20,7 @@ concurrency:
 jobs:
     build-element-web:
         name: Build element-web
-        uses: matrix-org/matrix-react-sdk/.github/workflows/element-web.yaml@v3.80.1
+        uses: matrix-org/matrix-react-sdk/.github/workflows/element-web.yaml@v3.82.0
         with:
             matrix-js-sdk-sha: ${{ github.sha }}
             react-sdk-repository: matrix-org/matrix-react-sdk

.github/workflows/pull_request.yaml

@@ -39,7 +39,7 @@ jobs:
         if: github.event.action == 'opened'
         steps:
             - name: Check membership
-              uses: tspascoal/get-user-teams-membership@37c08f7b52a72ca95d12af2e7ab2553ca9adf13b # v2
+              uses: tspascoal/get-user-teams-membership@ba78054988f58bea69b7c6136d563236f8ed2fc0 # v3
               id: teams
               with:
                   username: ${{ github.event.pull_request.user.login }}

.github/workflows/tests.yml

@@ -12,18 +12,19 @@ env:
     ENABLE_COVERAGE: ${{ github.event_name != 'merge_group' }}
 jobs:
     jest:
-        name: "Jest [${{ matrix.specs }}] (Node ${{ matrix.node }})"
+        name: "Jest [${{ matrix.specs }}] (Node ${{ matrix.node == '*' && 'latest' || matrix.node }})"
         runs-on: ubuntu-latest
         timeout-minutes: 10
         strategy:
             matrix:
                 specs: [integ, unit]
-                node: [18, latest]
+                node: [18, "*"]
         steps:
             - name: Checkout code
               uses: actions/checkout@v4
 
             - name: Setup Node
+              id: setupNode
               uses: actions/setup-node@v3
               with:
                   cache: "yarn"
@@ -51,7 +52,7 @@ jobs:
 
             - name: Move coverage files into place
               if: env.ENABLE_COVERAGE == 'true'
-              run: mv coverage/lcov.info coverage/${{ matrix.node }}-${{ matrix.specs }}.lcov.info
+              run: mv coverage/lcov.info coverage/${{ steps.setupNode.output.node-version }}-${{ matrix.specs }}.lcov.info
 
             - name: Upload Artifact
               if: env.ENABLE_COVERAGE == 'true'

.github/workflows/upgrade_dependencies.yml

@@ -1,38 +0,0 @@
-name: Upgrade Dependencies
-on:
-    workflow_dispatch: {}
-    workflow_call:
-        secrets:
-            ELEMENT_BOT_TOKEN:
-                required: true
-jobs:
-    upgrade:
-        runs-on: ubuntu-latest
-        steps:
-            - uses: actions/checkout@v4
-
-            - uses: actions/setup-node@v3
-              with:
-                  cache: "yarn"
-
-            - name: Upgrade
-              run: yarn upgrade && yarn install
-
-            - name: Create Pull Request
-              id: cpr
-              uses: peter-evans/create-pull-request@153407881ec5c347639a548ade7d8ad1d6740e38 # v5
-              with:
-                  token: ${{ secrets.ELEMENT_BOT_TOKEN }}
-                  branch: actions/upgrade-deps
-                  delete-branch: true
-                  title: Upgrade dependencies
-                  labels: |
-                      Dependencies
-                      T-Task
-
-            - name: Enable automerge
-              run: gh pr merge --merge --auto "$PR_NUMBER"
-              if: steps.cpr.outputs.pull-request-operation == 'created'
-              env:
-                  GH_TOKEN: ${{ secrets.ELEMENT_BOT_TOKEN }}
-                  PR_NUMBER: ${{ steps.cpr.outputs.pull-request-number }}

.husky/pre-commit

@@ -0,0 +1,4 @@
+#!/usr/bin/env sh
+. "$(dirname "$0")/_/husky.sh"
+
+npx lint-staged

.lintstagedrc

@@ -0,0 +1,4 @@
+{
+    "*.(ts|tsx)": ["eslint --fix", "prettier --write"],
+    "*.(py|md|yaml)": ["prettier --write"]
+}

CHANGELOG.md

@@ -1,5 +1,28 @@
-Changes in [29.1.0-rc.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v29.1.0-rc.1) (2023-10-17)
-============================================================================================================
+Changes in [30.0.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v30.0.0) (2023-11-07)
+==================================================================================================
+
+## 🚨 BREAKING CHANGES
+ * Refactor & make base64 functions browser-safe ([\#3818](https://github.com/matrix-org/matrix-js-sdk/pull/3818)).
+
+## 🦖 Deprecations
+ * Deprecate `MatrixEvent.toJSON` ([\#3801](https://github.com/matrix-org/matrix-js-sdk/pull/3801)).
+
+## ✨ Features
+ * Element-R: Add the git sha of the binding crate to `CryptoApi#getVersion` ([\#3838](https://github.com/matrix-org/matrix-js-sdk/pull/3838)). Contributed by @florianduros.
+ * Element-R: Wire up `globalBlacklistUnverifiedDevices` field to rust crypto encryption settings ([\#3790](https://github.com/matrix-org/matrix-js-sdk/pull/3790)). Fixes vector-im/element-web#26315. Contributed by @florianduros.
+ * Element-R: Wire up room rotation ([\#3807](https://github.com/matrix-org/matrix-js-sdk/pull/3807)). Fixes vector-im/element-web#26318. Contributed by @florianduros.
+ * Element-R: Add current version of the rust-sdk and vodozemac ([\#3825](https://github.com/matrix-org/matrix-js-sdk/pull/3825)). Contributed by @florianduros.
+ * Element-R: Wire up room history visibility ([\#3805](https://github.com/matrix-org/matrix-js-sdk/pull/3805)). Fixes vector-im/element-web#26319. Contributed by @florianduros.
+ * Element-R: log when we send to-device messages ([\#3810](https://github.com/matrix-org/matrix-js-sdk/pull/3810)).
+
+## 🐛 Bug Fixes
+ * Fix reemitter not being correctly wired on user objects created in storage classes ([\#3796](https://github.com/matrix-org/matrix-js-sdk/pull/3796)). Contributed by @MidhunSureshR.
+ * Element-R: silence log errors when viewing a pending event ([\#3824](https://github.com/matrix-org/matrix-js-sdk/pull/3824)).
+ * Don't emit a closed event if the indexeddb is closed by Element ([\#3832](https://github.com/matrix-org/matrix-js-sdk/pull/3832)). Fixes vector-im/element-web#25941. Contributed by @dhenneke.
+ * Element-R: silence log errors when viewing a decryption failure ([\#3821](https://github.com/matrix-org/matrix-js-sdk/pull/3821)).
+
+Changes in [29.1.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v29.1.0) (2023-10-24)
+==================================================================================================
 
 ## ✨ Features
  * OIDC: refresh tokens ([\#3764](https://github.com/matrix-org/matrix-js-sdk/pull/3764)). Contributed by @kerryarchibald.

package.json

@@ -1,6 +1,6 @@
 {
     "name": "matrix-js-sdk",
-    "version": "29.1.0-rc.1",
+    "version": "30.0.0",
     "description": "Matrix Client-Server SDK for Javascript",
     "engines": {
         "node": ">=18.0.0"
@@ -51,7 +51,7 @@
     ],
     "dependencies": {
         "@babel/runtime": "^7.12.5",
-        "@matrix-org/matrix-sdk-crypto-wasm": "^2.0.0",
+        "@matrix-org/matrix-sdk-crypto-wasm": "^2.2.0",
         "another-json": "^0.2.0",
         "bs58": "^5.0.0",
         "content-type": "^1.0.4",
@@ -78,8 +78,8 @@
         "@babel/preset-env": "^7.12.11",
         "@babel/preset-typescript": "^7.12.7",
         "@babel/register": "^7.12.10",
-        "@casualbot/jest-sonar-reporter": "^2.2.5",
-        "@matrix-org/olm": "https://gitlab.matrix.org/api/v4/projects/27/packages/npm/@matrix-org/olm/-/@matrix-org/olm-3.2.14.tgz",
+        "@casualbot/jest-sonar-reporter": "2.2.7",
+        "@matrix-org/olm": "3.2.15",
         "@types/bs58": "^4.0.1",
         "@types/content-type": "^1.1.5",
         "@types/debug": "^4.1.7",
@@ -95,7 +95,7 @@
         "babelify": "^10.0.0",
         "debug": "^4.3.4",
         "domexception": "^4.0.0",
-        "eslint": "8.49.0",
+        "eslint": "8.51.0",
         "eslint-config-google": "^0.14.0",
         "eslint-config-prettier": "^9.0.0",
         "eslint-import-resolver-typescript": "^3.5.1",
@@ -106,12 +106,14 @@
         "eslint-plugin-tsdoc": "^0.2.17",
         "eslint-plugin-unicorn": "^48.0.0",
         "exorcist": "^2.0.0",
-        "fake-indexeddb": "^4.0.0",
+        "fake-indexeddb": "^5.0.0",
         "fetch-mock-jest": "^1.5.1",
+        "husky": "^8.0.3",
         "jest": "^29.0.0",
         "jest-environment-jsdom": "^29.0.0",
         "jest-localstorage-mock": "^2.4.6",
         "jest-mock": "^29.0.0",
+        "lint-staged": "^15.0.2",
         "matrix-mock-request": "^2.5.0",
         "prettier": "2.8.8",
         "rimraf": "^5.0.0",

spec/integ/crypto/crypto.spec.ts

@@ -23,7 +23,14 @@ import { MockResponse, MockResponseFunction } from "fetch-mock";
 import Olm from "@matrix-org/olm";
 
 import * as testUtils from "../../test-utils/test-utils";
-import { CRYPTO_BACKENDS, getSyncResponse, InitCrypto, syncPromise } from "../../test-utils/test-utils";
+import {
+    advanceTimersUntil,
+    CRYPTO_BACKENDS,
+    getSyncResponse,
+    InitCrypto,
+    mkEventCustom,
+    syncPromise,
+} from "../../test-utils/test-utils";
 import * as testData from "../../test-utils/test-data";
 import {
     BOB_SIGNED_CROSS_SIGNING_KEYS_DATA,
@@ -37,6 +44,7 @@ import {
 import { TestClient } from "../../TestClient";
 import { logger } from "../../../src/logger";
 import {
+    Category,
     ClientEvent,
     createClient,
     CryptoEvent,
@@ -53,11 +61,12 @@ import {
     Room,
     RoomMember,
     RoomStateEvent,
+    HistoryVisibility,
 } from "../../../src/matrix";
 import { DeviceInfo } from "../../../src/crypto/deviceinfo";
 import { E2EKeyReceiver } from "../../test-utils/E2EKeyReceiver";
 import { ISyncResponder, SyncResponder } from "../../test-utils/SyncResponder";
-import { escapeRegExp } from "../../../src/utils";
+import { defer, escapeRegExp } from "../../../src/utils";
 import { downloadDeviceToJsDevice } from "../../../src/rust-crypto/device-converter";
 import { flushPromises } from "../../test-utils/flushPromises";
 import {
@@ -66,13 +75,19 @@ import {
     mockSetupMegolmBackupRequests,
 } from "../../test-utils/mockEndpoints";
 import { AddSecretStorageKeyOpts } from "../../../src/secret-storage";
-import { CrossSigningKey, CryptoCallbacks, KeyBackupInfo } from "../../../src/crypto-api";
+import {
+    CrossSigningKey,
+    CryptoCallbacks,
+    EventShieldColour,
+    EventShieldReason,
+    KeyBackupInfo,
+} from "../../../src/crypto-api";
 import { E2EKeyResponder } from "../../test-utils/E2EKeyResponder";
 import { DecryptionError } from "../../../src/crypto/algorithms";
 import { IKeyBackup } from "../../../src/crypto/backup";
 import {
-    createOlmSession,
     createOlmAccount,
+    createOlmSession,
     encryptGroupSessionKey,
     encryptMegolmEvent,
     encryptMegolmEventRawPlainText,
@@ -80,6 +95,7 @@ import {
     establishOlmSession,
     getTestOlmAccountKeys,
 } from "./olm-utils";
+import { ToDevicePayload } from "../../../src/models/ToDeviceMessage";
 
 afterEach(() => {
     // reset fake-indexeddb after each test, to make sure we don't leak connections
@@ -146,6 +162,27 @@ async function expectSendRoomKey(
     });
 }
 
+/**
+ * Return the event received on rooms/{roomId}/send/m.room.encrypted endpoint.
+ * See https://spec.matrix.org/latest/client-server-api/#put_matrixclientv3roomsroomidsendeventtypetxnid
+ * @returns the content of the encrypted event
+ */
+function expectEncryptedSendMessage() {
+    return new Promise<IContent>((resolve) => {
+        fetchMock.putOnce(
+            new RegExp("/send/m.room.encrypted/"),
+            (url, request) => {
+                const content = JSON.parse(request.body as string);
+                resolve(content);
+                return { event_id: "$event_id" };
+            },
+            // append to the list of intercepts on this path (since we have some tests that call
+            // this function multiple times)
+            { overwriteRoutes: false },
+        );
+    });
+}
+
 /**
  * Expect that the client sends an encrypted event
  *
@@ -159,22 +196,7 @@ async function expectSendRoomKey(
 async function expectSendMegolmMessage(
     inboundGroupSessionPromise: Promise<Olm.InboundGroupSession>,
 ): Promise<Partial<IEvent>> {
-    const encryptedMessageContent = await new Promise<IContent>((resolve) => {
-        fetchMock.putOnce(
-            new RegExp("/send/m.room.encrypted/"),
-            (url: string, opts: RequestInit): MockResponse => {
-                resolve(JSON.parse(opts.body as string));
-                return {
-                    event_id: "$event_id",
-                };
-            },
-            {
-                // append to the list of intercepts on this path (since we have some tests that call
-                // this function multiple times)
-                overwriteRoutes: false,
-            },
-        );
-    });
+    const encryptedMessageContent = await expectEncryptedSendMessage();
 
     // In some of the tests, the room key is sent *after* the actual event, so we may need to wait for it now.
     const inboundGroupSession = await inboundGroupSessionPromise;
@@ -922,6 +944,210 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("crypto (%s)", (backend: string,
                 aliceClient.sendTextMessage(ROOM_ID, "test"),
             ]);
         });
+
+        it("should send a m.unverified code in toDevice messages to an unverified device when globalBlacklistUnverifiedDevices=true", async () => {
+            aliceClient.getCrypto()!.globalBlacklistUnverifiedDevices = true;
+
+            expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+            await startClientAndAwaitFirstSync();
+            await establishOlmSession(aliceClient, keyReceiver, syncResponder, testOlmAccount);
+
+            // Tell alice we share a room with bob
+            syncResponder.sendOrQueueSyncResponse(getSyncResponse(["@bob:xyz"]));
+            await syncPromise(aliceClient);
+
+            // Force alice to download bob keys
+            expectAliceKeyQuery(getTestKeysQueryResponse("@bob:xyz"));
+
+            // Wait to receive the toDevice message and return bob device content
+            const toDevicePromise = new Promise<ToDevicePayload>((resolve) => {
+                fetchMock.putOnce(new RegExp("/sendToDevice/m.room_key.withheld/"), (url, request) => {
+                    const content = JSON.parse(request.body as string);
+                    resolve(content.messages["@bob:xyz"]["DEVICE_ID"]);
+                    return {};
+                });
+            });
+
+            // Mock endpoint of message sending
+            fetchMock.put(new RegExp("/send/"), { event_id: "$event_id" });
+
+            await aliceClient.sendTextMessage(ROOM_ID, "test");
+
+            // Finally, check that the toDevice message has the m.unverified code
+            const toDeviceContent = await toDevicePromise;
+            expect(toDeviceContent.code).toBe("m.unverified");
+        });
+    });
+
+    describe("Session should rotate according to encryption settings", () => {
+        /**
+         * Send a message to bob and get the encrypted message
+         * @returns {Promise<IContent>} The encrypted message
+         */
+        async function sendEncryptedMessage(): Promise<IContent> {
+            const [encryptedMessage] = await Promise.all([
+                expectEncryptedSendMessage(),
+                aliceClient.sendTextMessage(ROOM_ID, "test"),
+            ]);
+            return encryptedMessage;
+        }
+
+        afterEach(() => {
+            jest.useRealTimers();
+        });
+
+        newBackendOnly("should rotate the session after 2 messages", async () => {
+            expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+            await startClientAndAwaitFirstSync();
+            const p2pSession = await establishOlmSession(aliceClient, keyReceiver, syncResponder, testOlmAccount);
+
+            const syncResponse = getSyncResponse(["@bob:xyz"]);
+            // Every 2 messages in the room, the session should be rotated
+            syncResponse.rooms[Category.Join][ROOM_ID].state.events[0].content = {
+                algorithm: "m.megolm.v1.aes-sha2",
+                rotation_period_msgs: 2,
+            };
+
+            // Tell alice we share a room with bob
+            syncResponder.sendOrQueueSyncResponse(syncResponse);
+            await syncPromise(aliceClient);
+
+            // Force alice to download bob keys
+            expectAliceKeyQuery(getTestKeysQueryResponse("@bob:xyz"));
+
+            // Send a message to bob and get the encrypted message
+            const [encryptedMessage] = await Promise.all([
+                sendEncryptedMessage(),
+                expectSendRoomKey("@bob:xyz", testOlmAccount, p2pSession),
+            ]);
+
+            // Check that the session id exists
+            const sessionId = encryptedMessage.session_id;
+            expect(sessionId).toBeDefined();
+
+            // Send a second message to bob and get the current message
+            const secondEncryptedMessage = await sendEncryptedMessage();
+
+            // Check that the same session id is shared between the two messages
+            const secondSessionId = secondEncryptedMessage.session_id;
+            expect(secondSessionId).toBe(sessionId);
+
+            // The session should be rotated, we are expecting the room key to be sent
+            const [thirdEncryptedMessage] = await Promise.all([
+                sendEncryptedMessage(),
+                expectSendRoomKey("@bob:xyz", testOlmAccount, p2pSession),
+            ]);
+
+            // The session is rotated every 2 messages, we should have a new session id
+            const thirdSessionId = thirdEncryptedMessage.session_id;
+            expect(thirdSessionId).not.toBe(sessionId);
+        });
+
+        newBackendOnly("should rotate the session after 1h", async () => {
+            expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+            await startClientAndAwaitFirstSync();
+            const p2pSession = await establishOlmSession(aliceClient, keyReceiver, syncResponder, testOlmAccount);
+
+            // We need to fake the timers to advance the time
+            jest.useFakeTimers();
+
+            const syncResponse = getSyncResponse(["@bob:xyz"]);
+
+            // The minimum rotation period is 1h
+            // https://github.com/matrix-org/matrix-rust-sdk/blob/f75b2cd1d0981db42751dadb08c826740af1018e/crates/matrix-sdk-crypto/src/olm/group_sessions/outbound.rs#L410-L415
+            const oneHourInMs = 60 * 60 * 1000;
+
+            // Every 1h the session should be rotated
+            syncResponse.rooms[Category.Join][ROOM_ID].state.events[0].content = {
+                algorithm: "m.megolm.v1.aes-sha2",
+                rotation_period_ms: oneHourInMs,
+            };
+
+            // Tell alice we share a room with bob
+            syncResponder.sendOrQueueSyncResponse(syncResponse);
+            await syncPromise(aliceClient);
+
+            // Force alice to download bob keys
+            expectAliceKeyQuery(getTestKeysQueryResponse("@bob:xyz"));
+
+            // Send a message to bob and get the encrypted message
+            const [encryptedMessage] = await Promise.all([
+                sendEncryptedMessage(),
+                expectSendRoomKey("@bob:xyz", testOlmAccount, p2pSession),
+            ]);
+
+            // Check that the session id exists
+            const sessionId = encryptedMessage.session_id;
+            expect(sessionId).toBeDefined();
+
+            // Advance the time by 1h
+            jest.advanceTimersByTime(oneHourInMs);
+
+            // Send a second message to bob and get the encrypted message
+            const [secondEncryptedMessage] = await Promise.all([
+                sendEncryptedMessage(),
+                expectSendRoomKey("@bob:xyz", testOlmAccount, p2pSession),
+            ]);
+
+            // The session should be rotated
+            const secondSessionId = secondEncryptedMessage.session_id;
+            expect(secondSessionId).not.toBe(sessionId);
+        });
+    });
+
+    newBackendOnly("should rotate the session when the history visibility changes", async () => {
+        expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+        await startClientAndAwaitFirstSync();
+        const p2pSession = await establishOlmSession(aliceClient, keyReceiver, syncResponder, testOlmAccount);
+
+        // Tell alice we share a room with bob
+        syncResponder.sendOrQueueSyncResponse(getSyncResponse(["@bob:xyz"]));
+        await syncPromise(aliceClient);
+
+        // Force alice to download bob keys
+        expectAliceKeyQuery(getTestKeysQueryResponse("@bob:xyz"));
+
+        // Send a message to bob and get the current session id
+        let [, , encryptedMessage] = await Promise.all([
+            aliceClient.sendTextMessage(ROOM_ID, "test"),
+            expectSendRoomKey("@bob:xyz", testOlmAccount, p2pSession),
+            expectEncryptedSendMessage(),
+        ]);
+
+        // Check that the session id exists
+        const sessionId = encryptedMessage.session_id;
+        expect(sessionId).toBeDefined();
+
+        // Change history visibility in sync response
+        const syncResponse = getSyncResponse([]);
+        syncResponse.rooms[Category.Join][ROOM_ID].timeline.events.push(
+            mkEventCustom({
+                sender: TEST_USER_ID,
+                type: "m.room.history_visibility",
+                state_key: "",
+                content: {
+                    history_visibility: HistoryVisibility.Invited,
+                },
+            }),
+        );
+
+        // Update the new visibility
+        syncResponder.sendOrQueueSyncResponse(syncResponse);
+        await syncPromise(aliceClient);
+
+        // Resend a message to bob and get the new session id
+        [, , encryptedMessage] = await Promise.all([
+            aliceClient.sendTextMessage(ROOM_ID, "test"),
+            expectSendRoomKey("@bob:xyz", testOlmAccount, p2pSession),
+            expectEncryptedSendMessage(),
+        ]);
+
+        // Check that the new session id exists
+        const newSessionId = encryptedMessage.session_id;
+        expect(newSessionId).toBeDefined();
+
+        // Check that the session id has changed
+        expect(sessionId).not.toEqual(newSessionId);
     });
 
     oldBackendOnly("We should start a new megolm session when a device is blocked", async () => {
@@ -1700,6 +1926,105 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("crypto (%s)", (backend: string,
         await sendEventPromise;
     });
 
+    describe("getEncryptionInfoForEvent", () => {
+        it("handles outgoing events", async () => {
+            aliceClient.setGlobalErrorOnUnknownDevices(false);
+            expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+            await startClientAndAwaitFirstSync();
+
+            // Alice shares a room with Bob
+            syncResponder.sendOrQueueSyncResponse(getSyncResponse(["@bob:xyz"]));
+            await syncPromise(aliceClient);
+
+            // Once we send the message, Alice will check Bob's device list (twice, because reasons) ...
+            expectAliceKeyQuery(getTestKeysQueryResponse("@bob:xyz"));
+            expectAliceKeyQuery(getTestKeysQueryResponse("@bob:xyz"));
+
+            // ... and claim one of his OTKs ...
+            expectAliceKeyClaim(getTestKeysClaimResponse("@bob:xyz"));
+
+            // ... and send an m.room_key message ...
+            const inboundGroupSessionPromise = expectSendRoomKey("@bob:xyz", testOlmAccount);
+
+            // ... and finally, send the room key. We block the response until `sendRoomMessageDefer` completes.
+            const sendRoomMessageDefer = defer<MockResponse>();
+            const reqProm = new Promise<IContent>((resolve) => {
+                fetchMock.putOnce(
+                    new RegExp("/send/m.room.encrypted/"),
+                    async (url: string, opts: RequestInit): Promise<MockResponse> => {
+                        resolve(JSON.parse(opts.body as string));
+                        return await sendRoomMessageDefer.promise;
+                    },
+                    {
+                        // append to the list of intercepts on this path (since we have some tests that call
+                        // this function multiple times)
+                        overwriteRoutes: false,
+                    },
+                );
+            });
+
+            // Now we start to send the message
+            const sendProm = aliceClient.sendTextMessage(testData.TEST_ROOM_ID, "test");
+
+            // and wait for the outgoing requests
+            const inboundGroupSession = await inboundGroupSessionPromise;
+            const encryptedMessageContent = await reqProm;
+            const msg: any = inboundGroupSession.decrypt(encryptedMessageContent!.ciphertext);
+            logger.log("Decrypted received megolm message", msg);
+
+            // at this point, the request to send the room message has been made, but not completed.
+            // get hold of the pending event, and see what getEncryptionInfoForEvent makes of it
+            const pending = aliceClient.getRoom(testData.TEST_ROOM_ID)!.getPendingEvents();
+            expect(pending.length).toEqual(1);
+            const encInfo = await aliceClient.getCrypto()!.getEncryptionInfoForEvent(pending[0]);
+            expect(encInfo!.shieldColour).toEqual(EventShieldColour.NONE);
+            expect(encInfo!.shieldReason).toBeNull();
+
+            // release the send request
+            const resp = { event_id: "$event_id" };
+            sendRoomMessageDefer.resolve(resp);
+            expect(await sendProm).toEqual(resp);
+
+            // still pending at this point
+            expect(aliceClient.getRoom(testData.TEST_ROOM_ID)!.getPendingEvents().length).toEqual(1);
+
+            // echo the event back
+            const fullEvent = {
+                event_id: "$event_id",
+                type: "m.room.encrypted",
+                sender: aliceClient.getUserId(),
+                origin_server_ts: Date.now(),
+                content: encryptedMessageContent,
+            };
+            syncResponder.sendOrQueueSyncResponse({
+                next_batch: 1,
+                rooms: { join: { [testData.TEST_ROOM_ID]: { timeline: { events: [fullEvent] } } } },
+            });
+            await syncPromise(aliceClient);
+
+            const timelineEvents = aliceClient.getRoom(testData.TEST_ROOM_ID)!.getLiveTimeline()!.getEvents();
+            const lastEvent = timelineEvents[timelineEvents.length - 1];
+            expect(lastEvent.getId()).toEqual("$event_id");
+
+            // now check getEncryptionInfoForEvent again
+            const encInfo2 = await aliceClient.getCrypto()!.getEncryptionInfoForEvent(lastEvent);
+            let expectedEncryptionInfo;
+            if (backend === "rust-sdk") {
+                // rust crypto does not trust its own device until it is cross-signed.
+                expectedEncryptionInfo = {
+                    shieldColour: EventShieldColour.RED,
+                    shieldReason: EventShieldReason.UNSIGNED_DEVICE,
+                };
+            } else {
+                expectedEncryptionInfo = {
+                    shieldColour: EventShieldColour.NONE,
+                    shieldReason: null,
+                };
+            }
+            expect(encInfo2).toEqual(expectedEncryptionInfo);
+        });
+    });
+
     describe("Lazy-loading member lists", () => {
         let p2pSession: Olm.Session;
 
@@ -2483,7 +2808,9 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("crypto (%s)", (backend: string,
                 fetchMock.get("express:/_matrix/client/v3/room_keys/keys", keyBackupData);
 
                 // should be able to restore from 4S
-                const importResult = await aliceClient.restoreKeyBackupWithSecretStorage(check!.backupInfo!);
+                const importResult = await advanceTimersUntil(
+                    aliceClient.restoreKeyBackupWithSecretStorage(check!.backupInfo!),
+                );
                 expect(importResult.imported).toStrictEqual(1);
             });
 

spec/integ/crypto/megolm-backup.spec.ts

@@ -23,10 +23,17 @@ import { SyncResponder } from "../../test-utils/SyncResponder";
 import { E2EKeyReceiver } from "../../test-utils/E2EKeyReceiver";
 import { E2EKeyResponder } from "../../test-utils/E2EKeyResponder";
 import { mockInitialApiRequests } from "../../test-utils/mockEndpoints";
-import { awaitDecryption, CRYPTO_BACKENDS, InitCrypto, syncPromise } from "../../test-utils/test-utils";
+import {
+    advanceTimersUntil,
+    awaitDecryption,
+    CRYPTO_BACKENDS,
+    InitCrypto,
+    syncPromise,
+} from "../../test-utils/test-utils";
 import * as testData from "../../test-utils/test-data";
 import { KeyBackupInfo } from "../../../src/crypto-api/keybackup";
 import { IKeyBackup } from "../../../src/crypto/backup";
+import { flushPromises } from "../../test-utils/flushPromises";
 
 const ROOM_ID = testData.TEST_ROOM_ID;
 
@@ -110,9 +117,9 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
     /** an object which intercepts `/keys/query` requests on the test homeserver */
     let e2eKeyResponder: E2EKeyResponder;
 
-    jest.useFakeTimers();
-
     beforeEach(async () => {
+        jest.useFakeTimers();
+
         // anything that we don't have a specific matcher for silently returns a 404
         fetchMock.catch(404);
         fetchMock.config.warnOnFallback = false;
@@ -134,6 +141,7 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
         await jest.runAllTimersAsync();
 
         fetchMock.mockReset();
+        jest.restoreAllMocks();
     });
 
     async function initTestClient(opts: Partial<ICreateClientOpts> = {}): Promise<MatrixClient> {
@@ -149,64 +157,131 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
         return client;
     }
 
-    it("Alice checks key backups when receiving a message she can't decrypt", async function () {
-        const syncResponse = {
+    describe("Key backup check on UTD message", () => {
+        // sync response which contains an encrypted event
+        const SYNC_RESPONSE = {
             next_batch: 1,
-            rooms: {
-                join: {
-                    [ROOM_ID]: {
-                        timeline: {
-                            events: [testData.ENCRYPTED_EVENT],
-                        },
-                    },
-                },
-            },
+            rooms: { join: { [ROOM_ID]: { timeline: { events: [testData.ENCRYPTED_EVENT] } } } },
         };
 
-        fetchMock.get("express:/_matrix/client/v3/room_keys/keys/:room_id/:session_id", (url, request) => {
-            // check that the version is correct
-            const version = new URLSearchParams(new URL(url).search).get("version");
-            if (version == "1") {
-                return testData.CURVE25519_KEY_BACKUP_DATA;
-            } else {
-                return {
-                    status: 403,
-                    body: {
-                        current_version: "1",
-                        errcode: "M_WRONG_ROOM_KEYS_VERSION",
-                        error: "Wrong backup version.",
-                    },
-                };
+        const EXPECTED_URL =
+            [
+                "https://alice-server.com/_matrix/client/v3/room_keys/keys",
+                encodeURIComponent(testData.TEST_ROOM_ID),
+                encodeURIComponent(testData.MEGOLM_SESSION_DATA.session_id),
+            ].join("/") + "?version=1";
+
+        /** Flush promises enough times to get the crypto stacks to make the backup request */
+        async function flushBackupRequest() {
+            // we have to run flushPromises lots of times. It seems like each time the rust code touches indexeddb,
+            // it needs another round of flushPromises to progress, or something.
+            for (let i = 0; i < 10; i++) {
+                await flushPromises();
             }
+        }
+
+        beforeEach(async () => {
+            fetchMock.get("path:/_matrix/client/v3/room_keys/version", testData.SIGNED_BACKUP_DATA);
+
+            // ignore requests to send room key requests
+            fetchMock.put("express:/_matrix/client/v3/sendToDevice/m.room_key_request/:request_id", {});
+
+            aliceClient = await initTestClient();
+            const aliceCrypto = aliceClient.getCrypto()!;
+            await aliceCrypto.storeSessionBackupPrivateKey(
+                Buffer.from(testData.BACKUP_DECRYPTION_KEY_BASE64, "base64"),
+                testData.SIGNED_BACKUP_DATA.version!,
+            );
+
+            // start after saving the private key
+            await aliceClient.startClient();
+
+            // tell Alice to trust the dummy device that signed the backup, and re-check the backup.
+            // XXX: should we automatically re-check after a device becomes verified?
+            await waitForDeviceList();
+            await aliceClient.getCrypto()!.setDeviceVerified(testData.TEST_USER_ID, testData.TEST_DEVICE_ID);
+            await aliceClient.getCrypto()!.checkKeyBackupAndEnable();
         });
 
-        fetchMock.get("path:/_matrix/client/v3/room_keys/version", testData.SIGNED_BACKUP_DATA);
+        it("Alice checks key backups when receiving a message she can't decrypt", async () => {
+            fetchMock.get("express:/_matrix/client/v3/room_keys/keys/:room_id/:session_id", (url, request) => {
+                // check that the version is correct
+                const version = new URLSearchParams(new URL(url).search).get("version");
+                if (version == "1") {
+                    return testData.CURVE25519_KEY_BACKUP_DATA;
+                } else {
+                    return {
+                        status: 403,
+                        body: {
+                            current_version: "1",
+                            errcode: "M_WRONG_ROOM_KEYS_VERSION",
+                            error: "Wrong backup version.",
+                        },
+                    };
+                }
+            });
 
-        aliceClient = await initTestClient();
-        const aliceCrypto = aliceClient.getCrypto()!;
-        await aliceCrypto.storeSessionBackupPrivateKey(
-            Buffer.from(testData.BACKUP_DECRYPTION_KEY_BASE64, "base64"),
-            testData.SIGNED_BACKUP_DATA.version!,
-        );
+            // Send Alice a message that she won't be able to decrypt, and check that she fetches the key from the backup.
+            syncResponder.sendOrQueueSyncResponse(SYNC_RESPONSE);
+            await syncPromise(aliceClient);
 
-        // start after saving the private key
-        await aliceClient.startClient();
+            const room = aliceClient.getRoom(ROOM_ID)!;
+            const event = room.getLiveTimeline().getEvents()[0];
+            await advanceTimersUntil(awaitDecryption(event, { waitOnDecryptionFailure: true }));
 
-        // tell Alice to trust the dummy device that signed the backup, and re-check the backup.
-        // XXX: should we automatically re-check after a device becomes verified?
-        await waitForDeviceList();
-        await aliceCrypto.setDeviceVerified(testData.TEST_USER_ID, testData.TEST_DEVICE_ID);
-        await aliceClient.getCrypto()!.checkKeyBackupAndEnable();
+            expect(event.getContent()).toEqual(testData.CLEAR_EVENT.content);
+        });
 
-        // Now, send Alice a message that she won't be able to decrypt, and check that she fetches the key from the backup.
-        syncResponder.sendOrQueueSyncResponse(syncResponse);
-        await syncPromise(aliceClient);
+        it("handles error on backup query gracefully", async () => {
+            jest.spyOn(console, "error").mockImplementation(() => {});
 
-        const room = aliceClient.getRoom(ROOM_ID)!;
-        const event = room.getLiveTimeline().getEvents()[0];
-        await awaitDecryption(event, { waitOnDecryptionFailure: true });
+            fetchMock.get(
+                "express:/_matrix/client/v3/room_keys/keys/:room_id/:session_id",
+                { status: 404, body: { errcode: "M_NOT_FOUND" } },
+                { name: "getKey" },
+            );
 
-        expect(event.getContent()).toEqual(testData.CLEAR_EVENT.content);
+            // Send Alice a message that she won't be able to decrypt
+            syncResponder.sendOrQueueSyncResponse(SYNC_RESPONSE);
+            await flushBackupRequest();
+
+            const calls = fetchMock.calls("getKey");
+            expect(calls.length).toEqual(1);
+            expect(calls[0][0]).toEqual(EXPECTED_URL);
+
+            await flushBackupRequest();
+
+            // we should not have logged an error.
+            // eslint-disable-next-line no-console
+            expect(console.error).not.toHaveBeenCalled();
+        });
+
+        it("Only queries once", async () => {
+            fetchMock.get(
+                "express:/_matrix/client/v3/room_keys/keys/:room_id/:session_id",
+                { status: 404, body: { errcode: "M_NOT_FOUND" } },
+                { name: "getKey" },
+            );
+
+            // Send Alice a message that she won't be able to decrypt
+            syncResponder.sendOrQueueSyncResponse(SYNC_RESPONSE);
+            await flushBackupRequest();
+            const calls = fetchMock.calls("getKey");
+            expect(calls.length).toEqual(1);
+            expect(calls[0][0]).toEqual(EXPECTED_URL);
+
+            fetchMock.resetHistory();
+
+            // another message
+            const event2 = { ...testData.ENCRYPTED_EVENT, event_id: "$event2" };
+            const syncResponse2 = {
+                next_batch: 1,
+                rooms: { join: { [ROOM_ID]: { timeline: { events: [event2] } } } },
+            };
+            syncResponder.sendOrQueueSyncResponse(syncResponse2);
+            await flushBackupRequest();
+            expect(fetchMock.calls("getKey").length).toEqual(0);
+        });
     });
 
     describe("recover from backup", () => {
@@ -240,14 +315,16 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
                 onKeyCached = resolve;
             });
 
-            const result = await aliceClient.restoreKeyBackupWithRecoveryKey(
-                testData.BACKUP_DECRYPTION_KEY_BASE58,
-                undefined,
-                undefined,
-                check!.backupInfo!,
-                {
-                    cacheCompleteCallback: () => onKeyCached(),
-                },
+            const result = await advanceTimersUntil(
+                aliceClient.restoreKeyBackupWithRecoveryKey(
+                    testData.BACKUP_DECRYPTION_KEY_BASE58,
+                    undefined,
+                    undefined,
+                    check!.backupInfo!,
+                    {
+                        cacheCompleteCallback: () => onKeyCached(),
+                    },
+                ),
             );
 
             expect(result.imported).toStrictEqual(1);
@@ -255,7 +332,9 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
             await awaitKeyCached;
 
             // The key should be now cached
-            const afterCache = await aliceClient.restoreKeyBackupWithCache(undefined, undefined, check!.backupInfo!);
+            const afterCache = await advanceTimersUntil(
+                aliceClient.restoreKeyBackupWithCache(undefined, undefined, check!.backupInfo!),
+            );
 
             expect(afterCache.imported).toStrictEqual(1);
         });
@@ -278,11 +357,13 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
 
             const check = await aliceCrypto.checkKeyBackupAndEnable();
 
-            const result = await aliceClient.restoreKeyBackupWithRecoveryKey(
-                testData.BACKUP_DECRYPTION_KEY_BASE58,
-                ROOM_ID,
-                testData.MEGOLM_SESSION_DATA.session_id,
-                check!.backupInfo!,
+            const result = await advanceTimersUntil(
+                aliceClient.restoreKeyBackupWithRecoveryKey(
+                    testData.BACKUP_DECRYPTION_KEY_BASE58,
+                    ROOM_ID,
+                    testData.MEGOLM_SESSION_DATA.session_id,
+                    check!.backupInfo!,
+                ),
             );
 
             expect(result.imported).toStrictEqual(1);

spec/integ/crypto/olm-utils.ts

@@ -17,10 +17,11 @@ limitations under the License.
 import Olm from "@matrix-org/olm";
 import anotherjson from "another-json";
 
-import { IContent, IDeviceKeys, IEvent, MatrixClient } from "../../../src";
+import { IContent, IDeviceKeys, IDownloadKeyResult, IEvent, Keys, MatrixClient, SigningKeys } from "../../../src";
 import { IE2EKeyReceiver } from "../../test-utils/E2EKeyReceiver";
 import { ISyncResponder } from "../../test-utils/SyncResponder";
 import { syncPromise } from "../../test-utils/test-utils";
+import { KeyBackupInfo } from "../../../src/crypto-api";
 
 /**
  * @module
@@ -60,6 +61,117 @@ export function getTestOlmAccountKeys(olmAccount: Olm.Account, userId: string, d
     return testDeviceKeys;
 }
 
+/**
+ * Bootstrap cross signing for the given Olm account.
+ *
+ * Will generate the cross signing keys and sign them with the master key, and returns the `IDownloadKeyResult`
+ * that can be directly fed into a test e2eKeyResponder.
+ *
+ * The cross-signing keys are randomly generated, similar to how the olm account keys are generated. There may not
+ * be any value in using static vectors, as the device keys change at every test run.
+ *
+ * If some `KeyBackupInfo` are provided, the `auth_data` of each backup info will be signed with the
+ * master key, meaning the backups will be then trusted after verification.
+ *
+ * @param olmAccount - The Olm account object to use for signing the device keys.
+ * @param userId - The user ID to associate with the device keys.
+ * @param deviceId - The device ID to associate with the device keys.
+ * @param keyBackupInfo - Optional key backup infos to sign with the master key.
+ * @returns A valid keys/query response that can be fed into a test e2eKeyResponder.
+ */
+export function bootstrapCrossSigningTestOlmAccount(
+    olmAccount: Olm.Account,
+    userId: string,
+    deviceId: string,
+    keyBackupInfo: KeyBackupInfo[] = [],
+): Partial<IDownloadKeyResult> {
+    const olmAliceMSK = new global.Olm.PkSigning();
+    const masterPrivkey = olmAliceMSK.generate_seed();
+    const masterPubkey = olmAliceMSK.init_with_seed(masterPrivkey);
+
+    const olmAliceUSK = new global.Olm.PkSigning();
+    const userPrivkey = olmAliceUSK.generate_seed();
+    const userPubkey = olmAliceUSK.init_with_seed(userPrivkey);
+
+    const olmAliceSSK = new global.Olm.PkSigning();
+    const sskPrivkey = olmAliceSSK.generate_seed();
+    const sskPubkey = olmAliceSSK.init_with_seed(sskPrivkey);
+
+    const mskInfo: Keys = {
+        user_id: userId,
+        usage: ["master"],
+        keys: {
+            ["ed25519:" + masterPubkey]: masterPubkey,
+        },
+    };
+
+    const sskInfo: Partial<SigningKeys> = {
+        user_id: userId,
+        usage: ["self_signing"],
+        keys: {
+            ["ed25519:" + sskPubkey]: sskPubkey,
+        },
+    };
+    // sign the ssk with the msk
+    const sskSig = olmAliceMSK.sign(anotherjson.stringify(sskInfo));
+    sskInfo.signatures = {
+        [userId]: {
+            ["ed25519:" + masterPubkey]: sskSig,
+        },
+    };
+
+    const uskInfo: Partial<SigningKeys> = {
+        user_id: userId,
+        usage: ["user_signing"],
+        keys: {
+            ["ed25519:" + userPubkey]: userPubkey,
+        },
+    };
+
+    // sign the usk with the msk
+    const uskSig = olmAliceMSK.sign(anotherjson.stringify(uskInfo));
+    uskInfo.signatures = {
+        [userId]: {
+            ["ed25519:" + masterPubkey]: uskSig,
+        },
+    };
+
+    // get the device keys and sign them with the ssk (the device is then cross signed)
+    const deviceKeys = getTestOlmAccountKeys(olmAccount, userId, deviceId);
+
+    const copy = Object.assign({}, deviceKeys);
+    delete copy.signatures;
+    const crossSignature = olmAliceSSK.sign(anotherjson.stringify(copy));
+
+    // add the signature
+    deviceKeys.signatures![userId]["ed25519:" + sskPubkey] = crossSignature;
+
+    // if we have some key backup info, sign them with the msk
+    keyBackupInfo.forEach((info) => {
+        const unsignedAuthData = Object.assign({}, info.auth_data);
+        delete unsignedAuthData.signatures;
+        const backupSignature = olmAliceMSK.sign(anotherjson.stringify(unsignedAuthData));
+
+        info.auth_data.signatures = {
+            [userId]: {
+                ["ed25519:" + masterPubkey]: backupSignature,
+            },
+        };
+    });
+
+    // clean the olm resources as we don't need them anymore
+    olmAliceMSK.free();
+    olmAliceSSK.free();
+    olmAliceUSK.free();
+
+    return {
+        master_keys: { [userId]: mskInfo },
+        user_signing_keys: { [userId]: uskInfo as SigningKeys },
+        self_signing_keys: { [userId]: sskInfo as SigningKeys },
+        device_keys: { [userId]: { [deviceId]: deviceKeys } },
+    };
+}
+
 /** start an Olm session with a given recipient */
 export async function createOlmSession(
     olmAccount: Olm.Account,
@@ -218,6 +330,47 @@ export function encryptGroupSessionKey(opts: {
     });
 }
 
+/**
+ * Test utility to correctly encrypt a secret send event to a test device using the provided p2p session.
+ *
+ * @param opts - the options for the secret send event
+ * @returns the to-device event, ready to be returned in a sync response for the test device.
+ */
+export function encryptSecretSend(opts: {
+    /** the sender's user id */
+    sender: string;
+    /** recipient's user id */
+    recipient: string;
+    /** the recipient's curve25519 key */
+    recipientCurve25519Key: string;
+    /** the recipient's ed25519 key */
+    recipientEd25519Key: string;
+    /** sender's olm account */
+    olmAccount: Olm.Account;
+    /** sender's olm session with the recipient */
+    p2pSession: Olm.Session;
+    /** The requestId of the secret request that this secret send is replying. */
+    requestId: string;
+    /** The secret value */
+    secret: string;
+}): ToDeviceEvent {
+    const senderKeys = JSON.parse(opts.olmAccount.identity_keys());
+    return encryptOlmEvent({
+        sender: opts.sender,
+        senderKey: senderKeys.curve25519,
+        senderSigningKey: senderKeys.ed25519,
+        recipient: opts.recipient,
+        recipientCurve25519Key: opts.recipientCurve25519Key,
+        recipientEd25519Key: opts.recipientEd25519Key,
+        p2pSession: opts.p2pSession,
+        plaincontent: {
+            request_id: opts.requestId,
+            secret: opts.secret,
+        },
+        plaintype: "m.secret.send",
+    });
+}
+
 /**
  * Establish an Olm Session with the test user
  *

spec/integ/crypto/verification.spec.ts

@@ -26,6 +26,7 @@ import Olm from "@matrix-org/olm";
 import {
     createClient,
     CryptoEvent,
+    DeviceVerification,
     IContent,
     ICreateClientOpts,
     IEvent,
@@ -43,7 +44,7 @@ import {
     Verifier,
     VerifierEvent,
 } from "../../../src/crypto-api/verification";
-import { escapeRegExp } from "../../../src/utils";
+import { defer, escapeRegExp } from "../../../src/utils";
 import {
     awaitDecryption,
     CRYPTO_BACKENDS,
@@ -54,10 +55,12 @@ import {
 } from "../../test-utils/test-utils";
 import { SyncResponder } from "../../test-utils/SyncResponder";
 import {
+    BACKUP_DECRYPTION_KEY_BASE64,
     BOB_ONE_TIME_KEYS,
     BOB_SIGNED_CROSS_SIGNING_KEYS_DATA,
     BOB_SIGNED_TEST_DEVICE_DATA,
     BOB_TEST_USER_ID,
+    CURVE25519_KEY_BACKUP_DATA,
     MASTER_CROSS_SIGNING_PUBLIC_KEY_BASE64,
     SIGNED_CROSS_SIGNING_KEYS_DATA,
     SIGNED_TEST_DEVICE_DATA,
@@ -69,7 +72,16 @@ import {
 import { mockInitialApiRequests } from "../../test-utils/mockEndpoints";
 import { E2EKeyResponder } from "../../test-utils/E2EKeyResponder";
 import { E2EKeyReceiver } from "../../test-utils/E2EKeyReceiver";
-import { createOlmSession, encryptGroupSessionKey, encryptMegolmEvent, ToDeviceEvent } from "./olm-utils";
+import {
+    bootstrapCrossSigningTestOlmAccount,
+    createOlmSession,
+    encryptGroupSessionKey,
+    encryptMegolmEvent,
+    encryptSecretSend,
+    ToDeviceEvent,
+} from "./olm-utils";
+import { KeyBackupInfo } from "../../../src/crypto-api";
+import { encodeBase64 } from "../../../src/base64";
 
 // The verification flows use javascript timers to set timeouts. We tell jest to use mock timer implementations
 // to ensure that we don't end up with dangling timeouts.
@@ -1160,6 +1172,292 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("verification (%s)", (backend: st
         );
     });
 
+    describe("Secrets are gossiped after verification", () => {
+        // We use a legacy olm session as the existing session.
+        // This will give us access to low level olm functions in order to
+        // simulate a backup key request with proper olm encryption.
+        let testOlmAccount: Olm.Account;
+        const olmDeviceId = "OLM_DEVICE";
+        let usermasterPubKey: string;
+
+        const matchingBackupInfo: KeyBackupInfo = {
+            algorithm: "m.megolm_backup.v1.curve25519-aes-sha2",
+            version: "1",
+            auth_data: {
+                public_key: "hSDwCYkwp1R0i33ctD73Wg2/Og0mOBr066SpjqqbTmo",
+            },
+        };
+
+        const nonMatchingBackupInfo: KeyBackupInfo = {
+            algorithm: "m.megolm_backup.v1.curve25519-aes-sha2",
+            version: "1",
+            auth_data: {
+                public_key: "EjDwCYkwp1R0i33ctD73Wg2/Og0mOBr066Spjqqaqqo",
+            },
+        };
+
+        const unknownAlgorithmBackupInfo: KeyBackupInfo = {
+            algorithm: "m.megolm_backup.foo_bar",
+            version: "1",
+            auth_data: {
+                public_key: "EjDwCYkwp1R0i33ctD73Wg2/Og0mOBr066Spjqqaqqo",
+            },
+        };
+
+        beforeEach(async () => {
+            // create a test olm device which we will use to communicate with alice. We use libolm to implement this.
+            await Olm.init();
+            testOlmAccount = new Olm.Account();
+            testOlmAccount.create();
+
+            const bootstrapped = bootstrapCrossSigningTestOlmAccount(testOlmAccount, TEST_USER_ID, olmDeviceId, [
+                matchingBackupInfo,
+                nonMatchingBackupInfo,
+            ]);
+
+            e2eKeyResponder.addDeviceKeys(bootstrapped.device_keys![TEST_USER_ID]![olmDeviceId]);
+            e2eKeyResponder.addCrossSigningData(bootstrapped);
+
+            usermasterPubKey = Object.values(bootstrapped.master_keys![TEST_USER_ID].keys)[0];
+
+            aliceClient = await startTestClient();
+            syncResponder.sendOrQueueSyncResponse(getSyncResponse([TEST_USER_ID]));
+            await syncPromise(aliceClient);
+            // DeviceList has a sleep(5) which we need to make happen
+            await jest.advanceTimersByTimeAsync(10);
+
+            // The client should now know about the olm device
+            const devices = await aliceClient.getCrypto()!.getUserDeviceInfo([TEST_USER_ID]);
+            expect(devices.get(TEST_USER_ID)!.keys()).toContain(olmDeviceId);
+        });
+
+        afterEach(async () => {
+            aliceClient?.stopClient();
+            testOlmAccount?.free();
+
+            // Allow in-flight things to complete before we tear down the test
+            await jest.runAllTimersAsync();
+
+            fetchMock.mockReset();
+        });
+
+        newBackendOnly("Should request cross signing keys after verification", async () => {
+            const requestPromises = mockSecretRequestAndGetPromises();
+
+            await doInteractiveVerification();
+
+            // The secret must have been requested
+            await requestPromises.get("m.cross_signing.master");
+            await requestPromises.get("m.cross_signing.user_signing");
+            await requestPromises.get("m.cross_signing.self_signing");
+        });
+
+        newBackendOnly("Should accept the backup decryption key gossip if valid", async () => {
+            const requestPromises = mockSecretRequestAndGetPromises();
+
+            await doInteractiveVerification();
+
+            const requestId = await requestPromises.get("m.megolm_backup.v1");
+
+            await sendBackupGossipAndExpectVersion(requestId!, BACKUP_DECRYPTION_KEY_BASE64, matchingBackupInfo);
+
+            // We are lacking a way to signal that the secret has been received, so we wait a bit..
+            jest.useRealTimers();
+            await new Promise((resolve) => {
+                setTimeout(resolve, 500);
+            });
+            jest.useFakeTimers();
+
+            // the backup secret should be cached
+            const cachedKey = await aliceClient.getCrypto()!.getSessionBackupPrivateKey();
+            expect(cachedKey).toBeTruthy();
+            expect(encodeBase64(cachedKey!)).toEqual(BACKUP_DECRYPTION_KEY_BASE64);
+        });
+
+        newBackendOnly("Should not accept the backup decryption key gossip if private key do not match", async () => {
+            const requestPromises = mockSecretRequestAndGetPromises();
+
+            await doInteractiveVerification();
+
+            const requestId = await requestPromises.get("m.megolm_backup.v1");
+
+            await sendBackupGossipAndExpectVersion(requestId!, BACKUP_DECRYPTION_KEY_BASE64, nonMatchingBackupInfo);
+
+            // We are lacking a way to signal that the secret has been received, so we wait a bit..
+            jest.useRealTimers();
+            await new Promise((resolve) => {
+                setTimeout(resolve, 500);
+            });
+            jest.useFakeTimers();
+
+            // the backup secret should not be cached
+            const cachedKey = await aliceClient.getCrypto()!.getSessionBackupPrivateKey();
+            expect(cachedKey).toBeNull();
+        });
+
+        newBackendOnly("Should not accept the backup decryption key gossip if backup not trusted", async () => {
+            const requestPromises = mockSecretRequestAndGetPromises();
+
+            await doInteractiveVerification();
+
+            const requestId = await requestPromises.get("m.megolm_backup.v1");
+
+            const infoCopy = Object.assign({}, matchingBackupInfo);
+            delete infoCopy.auth_data.signatures;
+
+            await sendBackupGossipAndExpectVersion(requestId!, BACKUP_DECRYPTION_KEY_BASE64, infoCopy);
+
+            // We are lacking a way to signal that the secret has been received, so we wait a bit..
+            jest.useRealTimers();
+            await new Promise((resolve) => {
+                setTimeout(resolve, 500);
+            });
+            jest.useFakeTimers();
+
+            // the backup secret should not be cached
+            const cachedKey = await aliceClient.getCrypto()!.getSessionBackupPrivateKey();
+            expect(cachedKey).toBeNull();
+        });
+
+        newBackendOnly("Should not accept the backup decryption key gossip if backup algorithm unknown", async () => {
+            const requestPromises = mockSecretRequestAndGetPromises();
+
+            await doInteractiveVerification();
+
+            const requestId = await requestPromises.get("m.megolm_backup.v1");
+
+            await sendBackupGossipAndExpectVersion(
+                requestId!,
+                BACKUP_DECRYPTION_KEY_BASE64,
+                unknownAlgorithmBackupInfo,
+            );
+
+            // We are lacking a way to signal that the secret has been received, so we wait a bit..
+            jest.useRealTimers();
+            await new Promise((resolve) => {
+                setTimeout(resolve, 500);
+            });
+            jest.useFakeTimers();
+
+            // the backup secret should not be cached
+            const cachedKey = await aliceClient.getCrypto()!.getSessionBackupPrivateKey();
+            expect(cachedKey).toBeNull();
+        });
+
+        newBackendOnly("Should not accept an invalid backup decryption key", async () => {
+            const requestPromises = mockSecretRequestAndGetPromises();
+
+            await doInteractiveVerification();
+
+            const requestId = await requestPromises.get("m.megolm_backup.v1");
+
+            await sendBackupGossipAndExpectVersion(requestId!, "InvalidSecret", matchingBackupInfo);
+
+            // We are lacking a way to signal that the secret has been received, so we wait a bit..
+            jest.useRealTimers();
+            await new Promise((resolve) => {
+                setTimeout(resolve, 500);
+            });
+            jest.useFakeTimers();
+
+            // the backup secret should not be cached
+            const cachedKey = await aliceClient.getCrypto()!.getSessionBackupPrivateKey();
+            expect(cachedKey).toBeNull();
+        });
+
+        /**
+         * Common test setup for gossiping secrets.
+         * Creates a peer to peer session, sends the secret, mockup the version API, send the secret back from sync, then await for the backup check.
+         */
+        async function sendBackupGossipAndExpectVersion(
+            requestId: string,
+            secret: string,
+            expectBackup: KeyBackupInfo,
+        ) {
+            const p2pSession = await createOlmSession(testOlmAccount, e2eKeyReceiver);
+
+            const toDeviceEvent = encryptSecretSend({
+                sender: aliceClient.getUserId()!,
+                recipient: aliceClient.getUserId()!,
+                recipientCurve25519Key: e2eKeyReceiver.getDeviceKey(),
+                recipientEd25519Key: e2eKeyReceiver.getSigningKey(),
+                p2pSession: p2pSession,
+                olmAccount: testOlmAccount,
+                requestId: requestId!,
+                secret: secret,
+            });
+
+            const expectBackupCheck = new Promise((resolve) => {
+                fetchMock.get(
+                    "express:/_matrix/client/v3/room_keys/version",
+                    (url, request) => {
+                        resolve(undefined);
+                        return expectBackup;
+                    },
+                    {
+                        overwriteRoutes: true,
+                    },
+                );
+            });
+
+            fetchMock.get("express:/_matrix/client/v3/room_keys/keys", CURVE25519_KEY_BACKUP_DATA);
+
+            // The dummy device sends the secret
+            returnToDeviceMessageFromSync(toDeviceEvent);
+
+            await expectBackupCheck;
+        }
+
+        /**
+         * Do an interactive verification between alice and the dummy device.
+         */
+        async function doInteractiveVerification(): Promise<void> {
+            // Do a QR code verification for simplicity
+
+            // Alice sends a m.key.verification.request
+            const [, request] = await Promise.all([
+                expectSendToDeviceMessage("m.key.verification.request"),
+                aliceClient.getCrypto()!.requestDeviceVerification(TEST_USER_ID, olmDeviceId),
+            ]);
+            const transactionId = request.transactionId!;
+
+            // The dummy device replies with an m.key.verification.ready, indicating it can show a QR code
+            returnToDeviceMessageFromSync(
+                buildReadyMessage(transactionId, ["m.qr_code.show.v1", "m.reciprocate.v1"], olmDeviceId),
+            );
+            await waitForVerificationRequestChanged(request);
+
+            const currentDeviceKey = e2eKeyReceiver.getSigningKey();
+            // the dummy device shows a QR code
+            const sharedSecret = "SUPERSEKRET";
+            // use mode 0x01, self-verifying in which the current device does trust the master key
+            const mode = 0x01;
+            const qrCodeBuffer = buildQRCode(transactionId, usermasterPubKey, currentDeviceKey, sharedSecret, mode);
+
+            // Alice scans the QR code
+            const sendToDevicePromise = expectSendToDeviceMessage("m.key.verification.start");
+            const verifier = await request.scanQRCode(qrCodeBuffer);
+
+            await sendToDevicePromise;
+
+            const verificationPromise = verifier.verify();
+            // the dummy device confirms that Alice scanned the QR code, by replying with a done
+            returnToDeviceMessageFromSync(buildDoneMessage(transactionId));
+
+            // Alice also replies with a 'done'
+            await expectSendToDeviceMessage("m.key.verification.done");
+
+            // ... and the whole thing should be done!
+            await verificationPromise;
+
+            // The other device should now be verified.
+            const otherDevice = (await aliceClient.getCrypto()!.getUserDeviceInfo([TEST_USER_ID]))
+                .get(TEST_USER_ID)!
+                .get(olmDeviceId);
+            expect(otherDevice?.verified).toEqual(DeviceVerification.Verified);
+        }
+    });
+
     async function startTestClient(opts: Partial<ICreateClientOpts> = {}): Promise<MatrixClient> {
         const client = createClient({
             baseUrl: TEST_HOMESERVER_URL,
@@ -1221,6 +1519,52 @@ function expectSendToDeviceMessage(msgtype: string): Promise<{ messages: any }>
     });
 }
 
+/**
+ * Utility to add all needed mocks for secret requesting (to-device of type `m.secret.request`).
+ *
+ * The following secrets are mocked: `m.cross_signing.master`, `m.cross_signing.self_signing`,
+ * `m.cross_signing.user_signing`, `m.megolm_backup.v1`.
+ *
+ *  @returns a map of secret name to promise that will resolve (with the id of the secret request) when the secret is requested.
+ */
+function mockSecretRequestAndGetPromises(): Map<string, Promise<string>> {
+    const mskRequestDefer = defer<string>();
+    const sskRequestDefer = defer<string>();
+    const uskRequestDefer = defer<string>();
+    const backupKeyRequestDefer = defer<string>();
+
+    fetchMock.put(
+        new RegExp(`/_matrix/client/(r0|v3)/sendToDevice/m.secret.request`),
+        (url: string, opts: RequestInit): MockResponse => {
+            const messages = JSON.parse(opts.body as string).messages[TEST_USER_ID];
+            // rust crypto broadcasts to all devices, old crypto to a specific device, take the first one
+            const content = Object.values(messages)[0] as any;
+            if (content.action == "request") {
+                const name = content.name;
+                const requestId = content.request_id;
+                if (name == "m.cross_signing.user_signing") {
+                    uskRequestDefer.resolve(requestId);
+                } else if (name == "m.cross_signing.master") {
+                    mskRequestDefer.resolve(requestId);
+                } else if (name == "m.cross_signing.self_signing") {
+                    sskRequestDefer.resolve(requestId);
+                } else if (name == "m.megolm_backup.v1") {
+                    backupKeyRequestDefer.resolve(requestId);
+                }
+            }
+            return {};
+        },
+        { overwriteRoutes: true },
+    );
+
+    const promiseMap = new Map<string, Promise<string>>();
+    promiseMap.set("m.cross_signing.master", mskRequestDefer.promise);
+    promiseMap.set("m.cross_signing.self_signing", sskRequestDefer.promise);
+    promiseMap.set("m.cross_signing.user_signing", uskRequestDefer.promise);
+    promiseMap.set("m.megolm_backup.v1", backupKeyRequestDefer.promise);
+    return promiseMap;
+}
+
 /** wait for the verification request to emit a 'Change' event */
 function waitForVerificationRequestChanged(request: VerificationRequest): Promise<void> {
     return new Promise<void>((resolve) => {
@@ -1265,12 +1609,16 @@ function buildRequestMessage(transactionId: string): { type: string; content: ob
     };
 }
 
-/** build an m.key.verification.ready to-device message originating from the dummy device */
-function buildReadyMessage(transactionId: string, methods: string[]): { type: string; content: object } {
+/** build an m.key.verification.ready to-device message originating from the given `fromDevice` (default to `TEST_DEVICE_ID` if not provided) */
+function buildReadyMessage(
+    transactionId: string,
+    methods: string[],
+    fromDevice?: string,
+): { type: string; content: object } {
     return {
         type: "m.key.verification.ready",
         content: {
-            from_device: TEST_DEVICE_ID,
+            from_device: fromDevice || TEST_DEVICE_ID,
             methods: methods,
             transaction_id: transactionId,
         },
@@ -1368,14 +1716,20 @@ function buildDoneMessage(transactionId: string) {
     };
 }
 
-function buildQRCode(transactionId: string, key1Base64: string, key2Base64: string, sharedSecret: string): Uint8Array {
+function buildQRCode(
+    transactionId: string,
+    key1Base64: string,
+    key2Base64: string,
+    sharedSecret: string,
+    mode = 0x02,
+): Uint8Array {
     // https://spec.matrix.org/v1.7/client-server-api/#qr-code-format
 
     const qrCodeBuffer = Buffer.alloc(150); // oversize
     let idx = 0;
     idx += qrCodeBuffer.write("MATRIX", idx, "ascii");
     idx = qrCodeBuffer.writeUInt8(0x02, idx); // version
-    idx = qrCodeBuffer.writeUInt8(0x02, idx); // mode
+    idx = qrCodeBuffer.writeUInt8(mode, idx); // mode
     idx = qrCodeBuffer.writeInt16BE(transactionId.length, idx);
     idx += qrCodeBuffer.write(transactionId, idx, "ascii");
 

spec/integ/matrix-client-event-emitter.spec.ts

@@ -194,6 +194,37 @@ describe("MatrixClient events", function () {
             expect(fired).toBe(true);
         });
 
+        it("should emit User events when presence data is absent in first sync", async () => {
+            const MODIFIED_SYNC_DATA: any = structuredClone(SYNC_DATA);
+            delete MODIFIED_SYNC_DATA["presence"];
+            const MODIFIED_NEXT_SYNC_DATA: any = structuredClone(NEXT_SYNC_DATA);
+            MODIFIED_NEXT_SYNC_DATA.presence = {
+                events: [
+                    utils.mkPresence({
+                        user: "@foo:bar",
+                        name: "Foo Bar",
+                        presence: "online",
+                    }),
+                ],
+            };
+            httpBackend!.when("GET", "/sync").respond(200, MODIFIED_SYNC_DATA);
+            httpBackend!.when("GET", "/sync").respond(200, MODIFIED_NEXT_SYNC_DATA);
+            let fired = false;
+            client!.on(UserEvent.Presence, function (event, user) {
+                fired = true;
+                expect(user).toBeTruthy();
+                expect(event).toBeTruthy();
+                if (!user || !event) {
+                    return;
+                }
+                expect(event.event).toEqual(MODIFIED_NEXT_SYNC_DATA.presence.events[0]);
+                expect(user.presence).toEqual(MODIFIED_NEXT_SYNC_DATA.presence.events[0]?.content?.presence);
+            });
+            client!.startClient();
+            await httpBackend!.flushAllExpected();
+            expect(fired).toBe(true);
+        });
+
         it("should emit Room events", function () {
             httpBackend!.when("GET", "/sync").respond(200, SYNC_DATA);
             httpBackend!.when("GET", "/sync").respond(200, NEXT_SYNC_DATA);

spec/test-utils/test-utils.ts

@@ -537,8 +537,6 @@ export async function awaitDecryption(
     });
 }
 
-export const emitPromise = (e: EventEmitter, k: string): Promise<any> => new Promise((r) => e.once(k, r));
-
 export const mkPusher = (extra: Partial<IPusher> = {}): IPusher => ({
     app_display_name: "app",
     app_id: "123",
@@ -561,3 +559,25 @@ CRYPTO_BACKENDS["rust-sdk"] = (client: MatrixClient) => client.initRustCrypto();
 if (global.Olm) {
     CRYPTO_BACKENDS["libolm"] = (client: MatrixClient) => client.initCrypto();
 }
+
+export const emitPromise = (e: EventEmitter, k: string): Promise<any> => new Promise((r) => e.once(k, r));
+
+/**
+ * Advance the fake timers in a loop until the given promise resolves or rejects.
+ *
+ * Returns the result of the promise.
+ *
+ * This can be useful when there are multiple steps in the code which require an iteration of the event loop.
+ */
+export async function advanceTimersUntil<T>(promise: Promise<T>): Promise<T> {
+    let resolved = false;
+    promise.finally(() => {
+        resolved = true;
+    });
+
+    while (!resolved) {
+        await jest.advanceTimersByTimeAsync(1);
+    }
+
+    return await promise;
+}

spec/unit/base64.spec.ts

@@ -15,16 +15,44 @@ limitations under the License.
 */
 
 import { TextEncoder, TextDecoder } from "util";
+import NodeBuffer from "node:buffer";
 
-import { decodeBase64, encodeBase64, encodeUnpaddedBase64 } from "../../../src/common-crypto/base64";
+import { decodeBase64, encodeBase64, encodeUnpaddedBase64 } from "../../src/base64";
+
+describe.each(["browser", "node"])("Base64 encoding (%s)", (env) => {
+    let origBuffer = Buffer;
+
+    beforeAll(() => {
+        if (env === "browser") {
+            origBuffer = Buffer;
+            // @ts-ignore
+            // eslint-disable-next-line no-global-assign
+            Buffer = undefined;
+
+            global.atob = NodeBuffer.atob;
+            global.btoa = NodeBuffer.btoa;
+        }
+    });
+
+    afterAll(() => {
+        // eslint-disable-next-line no-global-assign
+        Buffer = origBuffer;
+        // @ts-ignore
+        global.atob = undefined;
+        // @ts-ignore
+        global.btoa = undefined;
+    });
 
-describe("Crypto Base64 encoding", () => {
     it("Should decode properly encoded data", async () => {
-        const toEncode = "encoding hello world";
-        const encoded = encodeBase64(new TextEncoder().encode(toEncode));
-        const decoded = new TextDecoder().decode(decodeBase64(encoded));
+        const decoded = new TextDecoder().decode(decodeBase64("ZW5jb2RpbmcgaGVsbG8gd29ybGQ="));
 
-        expect(decoded).toStrictEqual(toEncode);
+        expect(decoded).toStrictEqual("encoding hello world");
+    });
+
+    it("Should decode URL-safe base64", async () => {
+        const decoded = new TextDecoder().decode(decodeBase64("Pz8_Pz8="));
+
+        expect(decoded).toStrictEqual("?????");
     });
 
     it("Encode unpadded should not have padding", async () => {

spec/unit/crypto.spec.ts

@@ -115,6 +115,16 @@ describe("Crypto", function () {
         expect(Crypto.getOlmVersion()[0]).toEqual(3);
     });
 
+    it("getVersion() should return the current version of the olm library", async () => {
+        const client = new TestClient("@alice:example.com", "deviceid").client;
+        await client.initCrypto();
+
+        const olmVersionTuple = Crypto.getOlmVersion();
+        expect(client.getCrypto()?.getVersion()).toBe(
+            `Olm ${olmVersionTuple[0]}.${olmVersionTuple[1]}.${olmVersionTuple[2]}`,
+        );
+    });
+
     describe("encrypted events", function () {
         it("provides encryption information for events from unverified senders", async function () {
             const client = new TestClient("@alice:example.com", "deviceid").client;

spec/unit/crypto/secrets.spec.ts

@@ -28,6 +28,7 @@ import { DeviceInfo } from "../../../src/crypto/deviceinfo";
 import { ISignatures } from "../../../src/@types/signed";
 import { ICurve25519AuthData } from "../../../src/crypto/keybackup";
 import { SecretStorageKeyDescription, SECRET_STORAGE_ALGORITHM_V1_AES } from "../../../src/secret-storage";
+import { decodeBase64 } from "../../../src/base64";
 
 async function makeTestClient(
     userInfo: { userId: string; deviceId: string },
@@ -275,13 +276,13 @@ describe("Secrets", function () {
 
     describe("bootstrap", function () {
         // keys used in some of the tests
-        const XSK = new Uint8Array(olmlib.decodeBase64("3lo2YdJugHjfE+Or7KJ47NuKbhE7AAGLgQ/dc19913Q="));
+        const XSK = new Uint8Array(decodeBase64("3lo2YdJugHjfE+Or7KJ47NuKbhE7AAGLgQ/dc19913Q="));
         const XSPubKey = "DRb8pFVJyEJ9OWvXeUoM0jq/C2Wt+NxzBZVuk2nRb+0";
-        const USK = new Uint8Array(olmlib.decodeBase64("lKWi3hJGUie5xxHgySoz8PHFnZv6wvNaud/p2shN9VU="));
+        const USK = new Uint8Array(decodeBase64("lKWi3hJGUie5xxHgySoz8PHFnZv6wvNaud/p2shN9VU="));
         const USPubKey = "CUpoiTtHiyXpUmd+3ohb7JVxAlUaOG1NYs9Jlx8soQU";
-        const SSK = new Uint8Array(olmlib.decodeBase64("1R6JVlXX99UcfUZzKuCDGQgJTw8ur1/ofgPD8pp+96M="));
+        const SSK = new Uint8Array(decodeBase64("1R6JVlXX99UcfUZzKuCDGQgJTw8ur1/ofgPD8pp+96M="));
         const SSPubKey = "0DfNsRDzEvkCLA0gD3m7VAGJ5VClhjEsewI35xq873Q";
-        const SSSSKey = new Uint8Array(olmlib.decodeBase64("XrmITOOdBhw6yY5Bh7trb/bgp1FRdIGyCUxxMP873R0="));
+        const SSSSKey = new Uint8Array(decodeBase64("XrmITOOdBhw6yY5Bh7trb/bgp1FRdIGyCUxxMP873R0="));
 
         it("bootstraps when no storage or cross-signing keys locally", async function () {
             const key = new Uint8Array(16);

spec/unit/crypto/verification/secret_request.spec.ts

@@ -16,7 +16,7 @@ limitations under the License.
 
 import "../../../olm-loader";
 import { MatrixClient, MatrixEvent } from "../../../../src/matrix";
-import { encodeBase64 } from "../../../../src/crypto/olmlib";
+import { encodeBase64 } from "../../../../src/base64";
 import "../../../../src/crypto"; // import this to cycle-break
 import { CrossSigningInfo } from "../../../../src/crypto/CrossSigning";
 import { VerificationRequest } from "../../../../src/crypto/verification/request/VerificationRequest";

spec/unit/event-mapper.spec.ts

@@ -34,6 +34,7 @@ describe("eventMapperFor", function () {
                 getRoom(roomId: string): Room | null {
                     return rooms.find((r) => r.roomId === roomId) ?? null;
                 },
+                setUserCreator(_) {},
             } as IStore,
             scheduler: {
                 setProcessFunction: jest.fn(),

spec/unit/matrix-client.spec.ts

@@ -328,6 +328,7 @@ describe("MatrixClient", function () {
                 "storeFilter",
                 "startup",
                 "deleteAllData",
+                "setUserCreator",
             ] as const
         ).reduce((r, k) => {
             r[k] = jest.fn();

spec/unit/models/thread.spec.ts

@@ -675,6 +675,69 @@ describe("Thread", () => {
             });
         });
     });
+
+    describe("addEvent", () => {
+        describe("Given server support for threads", () => {
+            let previousThreadHasServerSideSupport: FeatureSupport;
+
+            beforeAll(() => {
+                previousThreadHasServerSideSupport = Thread.hasServerSideSupport;
+                Thread.hasServerSideSupport = FeatureSupport.Stable;
+            });
+
+            afterAll(() => {
+                Thread.hasServerSideSupport = previousThreadHasServerSideSupport;
+            });
+
+            it("Adds events even if they appear out of order", async () => {
+                // Given a thread exists
+                const client = createClient();
+                const user = "@alice:matrix.org";
+                const room = "!room:z";
+                const thread = await createThread(client, user, room);
+                const prevNumEvents = thread.timeline.length;
+
+                // When two messages come in but the later one has an older timestamp
+                const message1 = createThreadMessage(thread.id, user, room, "message1");
+                const message2 = createThreadMessage(thread.id, user, room, "message2");
+                message2.localTimestamp -= 10000;
+
+                await thread.addEvent(message1, false);
+                await thread.addEvent(message2, false);
+
+                // Then both events end up in the timeline
+                expect(thread.timeline.length - prevNumEvents).toEqual(2);
+                const lastEvent = thread.timeline.at(-1)!;
+                const secondLastEvent = thread.timeline.at(-2)!;
+                expect(lastEvent).toBe(message2);
+                expect(secondLastEvent).toBe(message1);
+            });
+
+            it("Adds events to start even if they appear out of order", async () => {
+                // Given a thread exists
+                const client = createClient();
+                const user = "@alice:matrix.org";
+                const room = "!room:z";
+                const thread = await createThread(client, user, room);
+                const prevNumEvents = thread.timeline.length;
+
+                // When two messages come in but the later one has an older timestamp
+                const message1 = createThreadMessage(thread.id, user, room, "message1");
+                const message2 = createThreadMessage(thread.id, user, room, "message2");
+                message2.localTimestamp -= 10000;
+
+                await thread.addEvent(message1, false);
+                await thread.addEvent(message2, true);
+
+                // Then both events end up in the timeline
+                expect(thread.timeline.length - prevNumEvents).toEqual(2);
+                const lastEvent = thread.timeline.at(-1)!;
+                const firstEvent = thread.timeline.at(0)!;
+                expect(lastEvent).toBe(message1);
+                expect(firstEvent).toBe(message2);
+            });
+        });
+    });
 });
 
 /**

spec/unit/rendezvous/ecdhv2.spec.ts

@@ -17,7 +17,7 @@ limitations under the License.
 import "../../olm-loader";
 import { RendezvousFailureReason, RendezvousIntent } from "../../../src/rendezvous";
 import { MSC3903ECDHPayload, MSC3903ECDHv2RendezvousChannel } from "../../../src/rendezvous/channels";
-import { decodeBase64 } from "../../../src/crypto/olmlib";
+import { decodeBase64 } from "../../../src/base64";
 import { DummyTransport } from "./DummyTransport";
 
 function makeTransport(name: string) {

spec/unit/rendezvous/rendezvous.spec.ts

@@ -29,7 +29,7 @@ import {
     MSC3886SimpleHttpRendezvousTransportDetails,
 } from "../../../src/rendezvous/transports";
 import { DummyTransport } from "./DummyTransport";
-import { decodeBase64 } from "../../../src/crypto/olmlib";
+import { decodeBase64 } from "../../../src/base64";
 import { logger } from "../../../src/logger";
 import { DeviceInfo } from "../../../src/crypto/deviceinfo";
 

spec/unit/rust-crypto/OutgoingRequestProcessor.spec.ts

@@ -82,12 +82,6 @@ describe("OutgoingRequestProcessor", () => {
             "https://example.com/_matrix/client/v3/keys/signatures/upload",
         ],
         ["KeysBackupRequest", KeysBackupRequest, "PUT", "https://example.com/_matrix/client/v3/room_keys/keys"],
-        [
-            "SigningKeysUploadRequest",
-            SigningKeysUploadRequest,
-            "POST",
-            "https://example.com/_matrix/client/v3/keys/device_signing/upload",
-        ],
     ];
 
     test.each(tests)(`should handle %ss`, async (_, RequestClass, expectedMethod, expectedPath) => {
@@ -121,7 +115,7 @@ describe("OutgoingRequestProcessor", () => {
 
     it("should handle ToDeviceRequests", async () => {
         // first, mock up the ToDeviceRequest as we might expect to receive it from the Rust layer ...
-        const testBody = '{ "foo": "bar" }';
+        const testBody = '{ "messages": { "user": {"device": "bar" }}}';
         const outgoingRequest = new ToDeviceRequest("1234", "test/type", "test/txnid", testBody);
 
         // ... then poke it into the OutgoingRequestProcessor under test.
@@ -179,10 +173,37 @@ describe("OutgoingRequestProcessor", () => {
         httpBackend.verifyNoOutstandingRequests();
     });
 
+    it("should handle SigningKeysUploadRequests without UIA", async () => {
+        // first, mock up a request as we might expect to receive it from the Rust layer ...
+        const testReq = { foo: "bar" };
+        const outgoingRequest = new SigningKeysUploadRequest(JSON.stringify(testReq));
+
+        // ... then poke the request into the OutgoingRequestProcessor under test
+        const reqProm = processor.makeOutgoingRequest(outgoingRequest);
+
+        // Now: check that it makes a matching HTTP request.
+        const testResponse = '{"result":1}';
+        httpBackend
+            .when("POST", "/_matrix")
+            .check((req) => {
+                expect(req.path).toEqual("https://example.com/_matrix/client/v3/keys/device_signing/upload");
+                expect(JSON.parse(req.rawData)).toEqual(testReq);
+                expect(req.headers["Accept"]).toEqual("application/json");
+                expect(req.headers["Content-Type"]).toEqual("application/json");
+            })
+            .respond(200, testResponse, true);
+
+        // SigningKeysUploadRequest does not need to be marked as sent, so no call to OlmMachine.markAsSent is expected.
+
+        await httpBackend.flushAllExpected();
+        await reqProm;
+        httpBackend.verifyNoOutstandingRequests();
+    });
+
     it("should handle SigningKeysUploadRequests with UIA", async () => {
         // first, mock up a request as we might expect to receive it from the Rust layer ...
         const testReq = { foo: "bar" };
-        const outgoingRequest = new SigningKeysUploadRequest("1234", JSON.stringify(testReq));
+        const outgoingRequest = new SigningKeysUploadRequest(JSON.stringify(testReq));
 
         // also create a UIA callback
         const authCallback: UIAuthCallback<Object> = async (makeRequest) => {
@@ -192,7 +213,7 @@ describe("OutgoingRequestProcessor", () => {
         // ... then poke the request into the OutgoingRequestProcessor under test
         const reqProm = processor.makeOutgoingRequest(outgoingRequest, authCallback);
 
-        // Now: check that it makes a matching HTTP request ...
+        // Now: check that it makes a matching HTTP request.
         const testResponse = '{"result":1}';
         httpBackend
             .when("POST", "/_matrix")
@@ -204,12 +225,10 @@ describe("OutgoingRequestProcessor", () => {
             })
             .respond(200, testResponse, true);
 
-        // ... and that it calls OlmMachine.markAsSent.
-        const markSentCallPromise = awaitCallToMarkAsSent();
-        await httpBackend.flushAllExpected();
+        // SigningKeysUploadRequest does not need to be marked as sent, so no call to OlmMachine.markAsSent is expected.
 
-        await Promise.all([reqProm, markSentCallPromise]);
-        expect(olmMachine.markRequestAsSent).toHaveBeenCalledWith("1234", outgoingRequest.type, testResponse);
+        await httpBackend.flushAllExpected();
+        await reqProm;
         httpBackend.verifyNoOutstandingRequests();
     });
 

spec/unit/rust-crypto/RoomEncryptor.spec.ts

@@ -0,0 +1,31 @@
+/*
+ *
+ * Copyright 2023 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 { HistoryVisibility as RustHistoryVisibility } from "@matrix-org/matrix-sdk-crypto-wasm";
+
+import { HistoryVisibility } from "../../../src";
+import { toRustHistoryVisibility } from "../../../src/rust-crypto/RoomEncryptor";
+
+it.each([
+    [HistoryVisibility.Invited, RustHistoryVisibility.Invited],
+    [HistoryVisibility.Joined, RustHistoryVisibility.Joined],
+    [HistoryVisibility.Shared, RustHistoryVisibility.Shared],
+    [HistoryVisibility.WorldReadable, RustHistoryVisibility.WorldReadable],
+])("JS HistoryVisibility to Rust HistoryVisibility: converts %s to %s", (historyVisibility, expected) => {
+    expect(toRustHistoryVisibility(historyVisibility)).toBe(expected);
+});

spec/unit/rust-crypto/rust-crypto.spec.ts

@@ -64,6 +64,9 @@ describe("initRustCrypto", () => {
         return {
             registerRoomKeyUpdatedCallback: jest.fn(),
             registerUserIdentityUpdatedCallback: jest.fn(),
+            getSecretsFromInbox: jest.fn().mockResolvedValue(["dGhpc2lzYWZha2VzZWNyZXQ="]),
+            deleteSecretsFromInbox: jest.fn(),
+            registerReceiveSecretCallback: jest.fn(),
             outgoingRequests: jest.fn(),
         } as unknown as Mocked<OlmMachine>;
     }
@@ -108,9 +111,35 @@ describe("initRustCrypto", () => {
 
         expect(OlmMachine.initialize).toHaveBeenCalledWith(expect.anything(), expect.anything(), undefined, undefined);
     });
+
+    it("Should get secrets from inbox on start", async () => {
+        const testOlmMachine = makeTestOlmMachine() as OlmMachine;
+        jest.spyOn(OlmMachine, "initialize").mockResolvedValue(testOlmMachine);
+
+        await initRustCrypto(
+            logger,
+            {} as MatrixClient["http"],
+            TEST_USER,
+            TEST_DEVICE_ID,
+            {} as ServerSideSecretStorage,
+            {} as CryptoCallbacks,
+            "storePrefix",
+            "storePassphrase",
+        );
+
+        expect(testOlmMachine.getSecretsFromInbox).toHaveBeenCalledWith("m.megolm_backup.v1");
+    });
 });
 
 describe("RustCrypto", () => {
+    it("getVersion() should return the current version of the rust sdk and vodozemac", async () => {
+        const rustCrypto = await makeTestRustCrypto();
+        const versions = RustSdkCryptoJs.getVersions();
+        expect(rustCrypto.getVersion()).toBe(
+            `Rust SDK ${versions.matrix_sdk_crypto} (${versions.git_sha}), Vodozemac ${versions.vodozemac}`,
+        );
+    });
+
     describe(".importRoomKeys and .exportRoomKeys", () => {
         let rustCrypto: RustCrypto;
 
@@ -484,6 +513,26 @@ describe("RustCrypto", () => {
             expect(olmMachine.getRoomEventEncryptionInfo).not.toHaveBeenCalled();
         });
 
+        it("should handle decryption failures", async () => {
+            const event = mkEvent({
+                event: true,
+                type: "m.room.encrypted",
+                content: { algorithm: "fake_alg" },
+                room: "!room:id",
+            });
+            event.event.event_id = "$event:id";
+            const mockCryptoBackend = {
+                decryptEvent: () => {
+                    throw new Error("UISI");
+                },
+            };
+            await event.attemptDecryption(mockCryptoBackend as unknown as CryptoBackend);
+
+            const res = await rustCrypto.getEncryptionInfoForEvent(event);
+            expect(res).toBe(null);
+            expect(olmMachine.getRoomEventEncryptionInfo).not.toHaveBeenCalled();
+        });
+
         it("passes the event into the OlmMachine", async () => {
             const encryptedEvent = await makeEncryptedEvent();
             const res = await rustCrypto.getEncryptionInfoForEvent(encryptedEvent);

spec/unit/stores/indexeddb.spec.ts

@@ -16,8 +16,9 @@ limitations under the License.
 
 import "fake-indexeddb/auto";
 import "jest-localstorage-mock";
+import { IDBFactory } from "fake-indexeddb";
 
-import { IndexedDBStore, IStateEventWithRoomId, MemoryStore } from "../../../src";
+import { IndexedDBStore, IStateEventWithRoomId, MemoryStore, User, UserEvent } from "../../../src";
 import { emitPromise } from "../../test-utils/test-utils";
 import { LocalIndexedDBStoreBackend } from "../../../src/store/indexeddb-local-backend";
 import { defer } from "../../../src/utils";
@@ -76,6 +77,62 @@ describe("IndexedDBStore", () => {
         expect(await store.getOutOfBandMembers(roomId)).toHaveLength(2);
     });
 
+    it("Should load presence events on startup", async () => {
+        // 1. Create idb database
+        const indexedDB = new IDBFactory();
+        const setupDefer = defer<Event>();
+        const req = indexedDB.open("matrix-js-sdk:db3", 1);
+        let db: IDBDatabase;
+        req.onupgradeneeded = () => {
+            db = req.result;
+            db.createObjectStore("users", { keyPath: ["userId"] });
+            db.createObjectStore("accountData", { keyPath: ["type"] });
+            db.createObjectStore("sync", { keyPath: ["clobber"] });
+        };
+        req.onsuccess = setupDefer.resolve;
+        await setupDefer.promise;
+
+        // 2. Fill in user presence data
+        const writeDefer = defer<Event>();
+        const transaction = db!.transaction(["users"], "readwrite");
+        const objectStore = transaction.objectStore("users");
+        const request = objectStore.put({
+            userId: "@alice:matrix.org",
+            event: {
+                content: {
+                    presence: "online",
+                },
+                sender: "@alice:matrix.org",
+                type: "m.presence",
+            },
+        });
+        request.onsuccess = writeDefer.resolve;
+        await writeDefer.promise;
+
+        // 3. Close database
+        req.result.close();
+
+        // 2. Check if the code loads presence events
+        const store = new IndexedDBStore({
+            indexedDB: indexedDB,
+            dbName: "db3",
+            localStorage,
+        });
+        let userCreated = false;
+        let presenceEventEmitted = false;
+        store.setUserCreator((id: string) => {
+            userCreated = true;
+            const user = new User(id);
+            user.on(UserEvent.Presence, () => {
+                presenceEventEmitted = true;
+            });
+            return user;
+        });
+        await store.startup();
+        expect(userCreated).toBe(true);
+        expect(presenceEventEmitted).toBe(true);
+    });
+
     it("should use MemoryStore methods for pending events if no localStorage", async () => {
         jest.spyOn(MemoryStore.prototype, "setPendingEvents");
         jest.spyOn(MemoryStore.prototype, "getPendingEvents");

src/base64.ts

@@ -0,0 +1,79 @@
+/*
+Copyright 2023 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.
+*/
+
+/**
+ * Base64 encoding and decoding utilities
+ */
+
+/**
+ * Encode a typed array of uint8 as base64.
+ * @param uint8Array - The data to encode.
+ * @returns The base64.
+ */
+export function encodeBase64(uint8Array: ArrayBuffer | Uint8Array): string {
+    // A brief note on the state of base64 encoding in Javascript.
+    // As of 2023, there is still no common native impl between both browsers and
+    // node. Older Webpack provides an impl for Buffer and there is a polyfill class
+    // for it. There are also plenty of pure js impls, eg. base64-js which has 2336
+    // dependents at current count. Using this would probably be fine although it's
+    // a little under-docced and run by an individual. The node impl works fine,
+    // the browser impl works but predates Uint8Array and so only uses strings.
+    // Right now, switching between native (or polyfilled) impls like this feels
+    // like the least bad option, but... *shrugs*.
+    if (typeof Buffer === "function") {
+        return Buffer.from(uint8Array).toString("base64");
+    } else if (typeof btoa === "function" && uint8Array instanceof Uint8Array) {
+        // ArrayBuffer is a node concept so the param should always be a Uint8Array on
+        // the browser. We need to check because ArrayBuffers don't have reduce.
+        return btoa(uint8Array.reduce((acc, current) => acc + String.fromCharCode(current), ""));
+    } else {
+        throw new Error("No base64 impl found!");
+    }
+}
+
+/**
+ * Encode a typed array of uint8 as unpadded base64.
+ * @param uint8Array - The data to encode.
+ * @returns The unpadded base64.
+ */
+export function encodeUnpaddedBase64(uint8Array: ArrayBuffer | Uint8Array): string {
+    return encodeBase64(uint8Array).replace(/={1,2}$/, "");
+}
+
+/**
+ * Decode a base64 string to a typed array of uint8.
+ * @param base64 - The base64 to decode.
+ * @returns The decoded data.
+ */
+export function decodeBase64(base64: string): Uint8Array {
+    // See encodeBase64 for a short treatise on base64 en/decoding in JS
+    if (typeof Buffer === "function") {
+        return Buffer.from(base64, "base64");
+    } else if (typeof atob === "function") {
+        const itFunc = function* (): Generator<number> {
+            const decoded = atob(
+                // built-in atob doesn't support base64url: convert so we support either
+                base64.replace("-", "+").replace("_", "/"),
+            );
+            for (let i = 0; i < decoded.length; ++i) {
+                yield decoded.charCodeAt(i);
+            }
+        };
+        return Uint8Array.from(itFunc());
+    } else {
+        throw new Error("No base64 impl found!");
+    }
+}

src/client.ts

@@ -47,7 +47,7 @@ import { Direction, EventTimeline } from "./models/event-timeline";
 import { IActionsObject, PushProcessor } from "./pushprocessor";
 import { AutoDiscovery, AutoDiscoveryAction } from "./autodiscovery";
 import * as olmlib from "./crypto/olmlib";
-import { decodeBase64, encodeBase64 } from "./crypto/olmlib";
+import { decodeBase64, encodeBase64 } from "./base64";
 import { IExportedDevice as IExportedOlmDevice } from "./crypto/OlmDevice";
 import { IOlmDevice } from "./crypto/algorithms/megolm";
 import { TypedReEmitter } from "./ReEmitter";
@@ -1342,6 +1342,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
 
         this.usingExternalCrypto = opts.usingExternalCrypto ?? false;
         this.store = opts.store || new StubStore();
+        this.store.setUserCreator((userId) => User.createUser(userId, this));
         this.deviceId = opts.deviceId || null;
         this.sessionId = randomString(10);
 
@@ -2679,12 +2680,12 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
      *
      * This API is currently UNSTABLE and may change or be removed without notice.
      *
+     * It has no effect with the Rust crypto implementation.
+     *
      * @param value - whether error on unknown devices
      *
-     * @deprecated Prefer direct access to {@link CryptoApi.globalBlacklistUnverifiedDevices}:
-     *
      * ```ts
-     * client.getCrypto().globalBlacklistUnverifiedDevices = value;
+     * client.getCrypto().globalErrorOnUnknownDevices = value;
      * ```
      */
     public setGlobalErrorOnUnknownDevices(value: boolean): void {

src/common-crypto/CryptoBackend.ts

@@ -35,8 +35,8 @@ export interface CryptoBackend extends SyncCryptoCallbacks, CryptoApi {
      * symmetry with setGlobalBlacklistUnverifiedDevices but there is currently
      * no room-level equivalent for this setting.
      *
-     * @remarks this is here, rather than in `CryptoApi`, because I don't think we're
-     * going to support it in the rust crypto implementation.
+     * @remarks This has no effect in Rust Crypto; it exists only for the sake of
+     * the accessors in MatrixClient.
      */
     globalErrorOnUnknownDevices: boolean;
 

src/common-crypto/base64.ts

@@ -1,46 +0,0 @@
-/*
-Copyright 2023 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.
-*/
-
-/**
- * Base64 encoding and decoding utility for crypo.
- */
-
-/**
- * Encode a typed array of uint8 as base64.
- * @param uint8Array - The data to encode.
- * @returns The base64.
- */
-export function encodeBase64(uint8Array: ArrayBuffer | Uint8Array): string {
-    return Buffer.from(uint8Array).toString("base64");
-}
-
-/**
- * Encode a typed array of uint8 as unpadded base64.
- * @param uint8Array - The data to encode.
- * @returns The unpadded base64.
- */
-export function encodeUnpaddedBase64(uint8Array: ArrayBuffer | Uint8Array): string {
-    return encodeBase64(uint8Array).replace(/={1,2}$/, "");
-}
-
-/**
- * Decode a base64 string to a typed array of uint8.
- * @param base64 - The base64 to decode.
- * @returns The decoded data.
- */
-export function decodeBase64(base64: string): Uint8Array {
-    return Buffer.from(base64, "base64");
-}

src/crypto-api.ts

@@ -39,6 +39,13 @@ export interface CryptoApi {
      */
     globalBlacklistUnverifiedDevices: boolean;
 
+    /**
+     * Return the current version of the crypto module.
+     * For example: `Rust SDK ${versions.matrix_sdk_crypto} (${versions.git_sha}), Vodozemac ${versions.vodozemac}`.
+     * @returns the formatted version
+     */
+    getVersion(): string;
+
     /**
      * Perform any background tasks that can be done before a message is ready to
      * send, in order to speed up sending of the message.

src/crypto/CrossSigning.ts

@@ -19,7 +19,7 @@ limitations under the License.
  */
 
 import type { PkSigning } from "@matrix-org/olm";
-import { decodeBase64, encodeBase64, IObject, pkSign, pkVerify } from "./olmlib";
+import { IObject, pkSign, pkVerify } from "./olmlib";
 import { logger } from "../logger";
 import { IndexedDBCryptoStore } from "../crypto/store/indexeddb-crypto-store";
 import { decryptAES, encryptAES } from "./aes";
@@ -31,6 +31,7 @@ import { ISignatures } from "../@types/signed";
 import { CryptoStore, SecretStorePrivateKeys } from "./store/base";
 import { ServerSideSecretStorage, SecretStorageKeyDescription } from "../secret-storage";
 import { DeviceVerificationStatus, UserVerificationStatus as UserTrustLevel } from "../crypto-api";
+import { decodeBase64, encodeBase64 } from "../base64";
 
 // backwards-compatibility re-exports
 export { UserTrustLevel };

src/crypto/aes.ts

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { decodeBase64, encodeBase64 } from "./olmlib";
+import { decodeBase64, encodeBase64 } from "../base64";
 import { subtleCrypto, crypto, TextEncoder } from "./crypto";
 
 // salt for HKDF, with 8 bytes of zeros

src/crypto/dehydration.ts

@@ -17,7 +17,7 @@ limitations under the License.
 import anotherjson from "another-json";
 
 import type { IDeviceKeys, IOneTimeKey } from "../@types/crypto";
-import { decodeBase64, encodeBase64 } from "./olmlib";
+import { decodeBase64, encodeBase64 } from "../base64";
 import { IndexedDBCryptoStore } from "../crypto/store/indexeddb-crypto-store";
 import { decryptAES, encryptAES } from "./aes";
 import { logger } from "../logger";

src/crypto/index.ts

@@ -102,6 +102,7 @@ import {
 import { Device, DeviceMap } from "../models/device";
 import { deviceInfoToDevice } from "./device-converter";
 import { ClientPrefix, MatrixError, Method } from "../http-api";
+import { decodeBase64, encodeBase64 } from "../base64";
 
 /* re-exports for backwards compatibility */
 export type {
@@ -500,7 +501,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
                     await this.secretStorage.store("m.megolm_backup.v1", fixedKey, [keys![0]]);
                 }
 
-                return olmlib.decodeBase64(fixedKey || storedKey);
+                return decodeBase64(fixedKey || storedKey);
             }
 
             // try to get key from app
@@ -609,6 +610,14 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
         this.backupManager.checkAndStart();
     }
 
+    /**
+     * Implementation of {@link CryptoApi#getVersion}.
+     */
+    public getVersion(): string {
+        const olmVersionTuple = Crypto.getOlmVersion();
+        return `Olm ${olmVersionTuple[0]}.${olmVersionTuple[1]}.${olmVersionTuple[2]}`;
+    }
+
     /**
      * Whether to trust a others users signatures of their devices.
      * If false, devices will only be considered 'verified' if we have
@@ -1050,7 +1059,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
             newKeyId = await createSSSS(opts, backupKey);
 
             // store the backup key in secret storage
-            await secretStorage.store("m.megolm_backup.v1", olmlib.encodeBase64(backupKey!), [newKeyId]);
+            await secretStorage.store("m.megolm_backup.v1", encodeBase64(backupKey!), [newKeyId]);
 
             // The backup is trusted because the user provided the private key.
             // Sign the backup with the cross-signing key so the key backup can
@@ -1094,7 +1103,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
             );
             // write the key to 4S
             const privateKey = decodeRecoveryKey(info.recovery_key);
-            await secretStorage.store("m.megolm_backup.v1", olmlib.encodeBase64(privateKey));
+            await secretStorage.store("m.megolm_backup.v1", encodeBase64(privateKey));
 
             // create keyBackupInfo object to add to builder
             const data: IKeyBackupInfo = {
@@ -1122,7 +1131,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
                 const keyId = newKeyId || oldKeyId;
                 await secretStorage.store("m.megolm_backup.v1", fixedBackupKey, keyId ? [keyId] : null);
             }
-            const decodedBackupKey = new Uint8Array(olmlib.decodeBase64(fixedBackupKey || sessionBackupKey));
+            const decodedBackupKey = new Uint8Array(decodeBase64(fixedBackupKey || sessionBackupKey));
             builder.addSessionBackupPrivateKeyToCache(decodedBackupKey);
         } else if (this.backupManager.getKeyBackupEnabled()) {
             // key backup is enabled but we don't have a session backup key in SSSS: see if we have one in
@@ -1137,7 +1146,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
                 return;
             }
             logger.info("Got session backup key from cache/user that wasn't in SSSS: saving to SSSS");
-            await secretStorage.store("m.megolm_backup.v1", olmlib.encodeBase64(backupKey));
+            await secretStorage.store("m.megolm_backup.v1", encodeBase64(backupKey));
         }
 
         const operation = builder.buildOperation();
@@ -1178,7 +1187,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
 
         // write the key to 4S
         const privateKey = info.privateKey;
-        await this.secretStorage.store("m.megolm_backup.v1", olmlib.encodeBase64(privateKey));
+        await this.secretStorage.store("m.megolm_backup.v1", encodeBase64(privateKey));
         await this.storeSessionBackupPrivateKey(privateKey);
 
         await this.backupManager.checkAndStart();
@@ -1301,13 +1310,13 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
 
         // make sure we have a Uint8Array, rather than a string
         if (typeof encodedKey === "string") {
-            key = new Uint8Array(olmlib.decodeBase64(fixBackupKey(encodedKey) || encodedKey));
+            key = new Uint8Array(decodeBase64(fixBackupKey(encodedKey) || encodedKey));
             await this.storeSessionBackupPrivateKey(key);
         }
         if (encodedKey && typeof encodedKey === "object" && "ciphertext" in encodedKey) {
             const pickleKey = Buffer.from(this.olmDevice.pickleKey);
             const decrypted = await decryptAES(encodedKey, pickleKey, "m.megolm_backup.v1");
-            key = olmlib.decodeBase64(decrypted);
+            key = decodeBase64(decrypted);
         }
         return key;
     }
@@ -1323,7 +1332,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
             throw new Error(`storeSessionBackupPrivateKey expects Uint8Array, got ${key}`);
         }
         const pickleKey = Buffer.from(this.olmDevice.pickleKey);
-        const encryptedKey = await encryptAES(olmlib.encodeBase64(key), pickleKey, "m.megolm_backup.v1");
+        const encryptedKey = await encryptAES(encodeBase64(key), pickleKey, "m.megolm_backup.v1");
         return this.cryptoStore.doTxn("readwrite", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
             this.cryptoStore.storeSecretStorePrivateKey(txn, "m.megolm_backup.v1", encryptedKey);
         });
@@ -4196,7 +4205,7 @@ export function fixBackupKey(key?: string): string | null {
         return null;
     }
     const fixedKey = Uint8Array.from(key.split(","), (x) => parseInt(x));
-    return olmlib.encodeBase64(fixedKey);
+    return encodeBase64(fixedKey);
 }
 
 /**

src/crypto/olmlib.ts

@@ -537,30 +537,3 @@ export function isOlmEncrypted(event: MatrixEvent): boolean {
     }
     return true;
 }
-
-/**
- * Encode a typed array of uint8 as base64.
- * @param uint8Array - The data to encode.
- * @returns The base64.
- */
-export function encodeBase64(uint8Array: ArrayBuffer | Uint8Array): string {
-    return Buffer.from(uint8Array).toString("base64");
-}
-
-/**
- * Encode a typed array of uint8 as unpadded base64.
- * @param uint8Array - The data to encode.
- * @returns The unpadded base64.
- */
-export function encodeUnpaddedBase64(uint8Array: ArrayBuffer | Uint8Array): string {
-    return encodeBase64(uint8Array).replace(/=+$/g, "");
-}
-
-/**
- * Decode a base64 string to a typed array of uint8.
- * @param base64 - The base64 to decode.
- * @returns The decoded data.
- */
-export function decodeBase64(base64: string): Uint8Array {
-    return Buffer.from(base64, "base64");
-}

src/crypto/verification/QRCode.ts

@@ -21,7 +21,7 @@ limitations under the License.
 import { crypto } from "../crypto";
 import { VerificationBase as Base } from "./Base";
 import { newKeyMismatchError, newUserCancelledError } from "./Error";
-import { decodeBase64, encodeUnpaddedBase64 } from "../olmlib";
+import { decodeBase64, encodeUnpaddedBase64 } from "../../base64";
 import { logger } from "../../logger";
 import { VerificationRequest } from "./request/VerificationRequest";
 import { MatrixClient } from "../../client";

src/matrix.ts

@@ -29,6 +29,7 @@ export * from "./http-api";
 export * from "./autodiscovery";
 export * from "./sync-accumulator";
 export * from "./errors";
+export * from "./base64";
 export * from "./models/beacon";
 export * from "./models/event";
 export * from "./models/room";

src/matrixrtc/MatrixRTCSession.ts

@@ -118,10 +118,12 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         }
 
         callMemberships.sort((a, b) => a.createdTs() - b.createdTs());
-        logger.debug(
-            "Call memberships, in order: ",
-            callMemberships.map((m) => [m.createdTs(), m.sender]),
-        );
+        if (callMemberships.length > 1) {
+            logger.debug(
+                `Call memberships in room ${room.roomId}, in order: `,
+                callMemberships.map((m) => [m.createdTs(), m.sender]),
+            );
+        }
 
         return callMemberships;
     }

src/models/event.ts

@@ -414,9 +414,12 @@ export class MatrixEvent extends TypedEventEmitter<MatrixEventEmittedEvents, Mat
     }
 
     /**
-     * Gets the event as though it would appear unencrypted. If the event is already not
-     * encrypted, it is simply returned as-is.
-     * @returns The event in wire format.
+     * Gets the event as it would appear if it had been sent unencrypted.
+     *
+     * If the event is encrypted, we attempt to mock up an event as it would have looked had the sender not encrypted it.
+     * If the event is not encrypted, a copy of it is simply returned as-is.
+     *
+     * @returns A shallow copy of the event, in wire format, as it would have been had it not been encrypted.
      */
     public getEffectiveEvent(): IEvent {
         const content = Object.assign({}, this.getContent()); // clone for mutation
@@ -1593,15 +1596,21 @@ export class MatrixEvent extends TypedEventEmitter<MatrixEventEmittedEvents, Mat
     }
 
     /**
-     * Summarise the event as JSON. This is currently used by React SDK's view
-     * event source feature and Seshat's event indexing, so take care when
-     * adjusting the output here.
+     * Summarise the event as JSON.
      *
      * If encrypted, include both the decrypted and encrypted view of the event.
      *
      * This is named `toJSON` for use with `JSON.stringify` which checks objects
      * for functions named `toJSON` and will call them to customise the output
      * if they are defined.
+     *
+     * **WARNING** Do not log the result of this method; otherwise, it will end up
+     * in rageshakes, leading to a privacy violation.
+     *
+     * @deprecated Prefer to use {@link MatrixEvent#getEffectiveEvent} or similar.
+     * This method will be removed soon; it is too easy to use it accidentally
+     * and cause a privacy violation (cf https://github.com/vector-im/element-web/issues/26380).
+     * In any case, the value it returns is not a faithful serialization of the object.
      */
     public toJSON(): object {
         const event = this.getEffectiveEvent();

src/models/thread.ts

@@ -430,22 +430,19 @@ export class Thread extends ReadReceipt<ThreadEmittedEvents, ThreadEventHandlerM
             // If initial events have not been fetched, we are OK to throw away
             // this event, because we are about to fetch all the events for this
             // thread from the server.
-            //
-            // If not, this looks like a bug - we should always add the event to
-            // the thread. See https://github.com/vector-im/element-web/issues/26254
-            logger.warn(
-                `Not adding event ${event.getId()} to thread timeline!
-                isNewestReply=${isNewestReply}
-                event.localTimestamp=${event.localTimestamp}
-                !!lastReply=${!!lastReply}
-                lastReply?.getId()=${lastReply?.getId()}
-                lastReply?.localTimestamp=${lastReply?.localTimestamp}
-                toStartOfTimeline=${toStartOfTimeline}
-                Thread.hasServerSideSupport=${Thread.hasServerSideSupport}
-                event.isRelation(RelationType.Annotation)=${event.isRelation(RelationType.Annotation)}
-                event.isRelation(RelationType.Replace)=${event.isRelation(RelationType.Replace)}
-                `,
-            );
+
+            // Otherwise, we should add it, but we suspect it is out of order.
+            if (toStartOfTimeline) {
+                // If we're adding at the start of the timeline, it doesn't
+                // matter that it's out of order.
+                this.addEventToTimeline(event, toStartOfTimeline);
+            } else {
+                // We think this event might be out of order, because isNewestReply
+                // is false (otherwise we would have gone into the earlier if
+                // clause), so try to insert it in the right place based on
+                // timestamp.
+                this.insertEventIntoTimeline(event);
+            }
         }
 
         if (

src/models/user.ts

@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { MatrixClient } from "../matrix";
 import { MatrixEvent } from "./event";
 import { TypedEventEmitter } from "./typed-event-emitter";
 
@@ -152,6 +153,7 @@ export class User extends TypedEventEmitter<UserEvent, UserEventHandlerMap> {
     /**
      * Construct a new User. A User must have an ID and can optionally have extra information associated with it.
      * @param userId - Required. The ID of this user.
+     * @deprecated use `User.createUser`
      */
     public constructor(public readonly userId: string) {
         super();
@@ -160,6 +162,25 @@ export class User extends TypedEventEmitter<UserEvent, UserEventHandlerMap> {
         this.updateModifiedTime();
     }
 
+    /**
+     * Construct a new User whose events will also emit on MatrixClient.
+     * A User must have an ID and can optionally have extra information associated with it.
+     * @param userId - Required. The ID of this user.
+     * @param client - An instance of MatrixClient object
+     * @returns User object with reEmitter setup on client
+     */
+    public static createUser(userId: string, client: MatrixClient): User {
+        const user = new User(userId);
+        client.reEmitter.reEmit(user, [
+            UserEvent.AvatarUrl,
+            UserEvent.DisplayName,
+            UserEvent.Presence,
+            UserEvent.CurrentlyActive,
+            UserEvent.LastPresenceTs,
+        ]);
+        return user;
+    }
+
     /**
      * Update this User with the given presence event. May fire "User.presence",
      * "User.avatarUrl" and/or "User.displayName" if this event updates this user's

src/oidc/authorize.ts

@@ -198,7 +198,8 @@ const normalizeBearerTokenResponseTokenType = (response: SigninResponse): Bearer
  * @param code - authorization code as returned by OP during authorization
  * @param storedAuthorizationParams - stored params from start of oidc login flow
  * @returns valid bearer token response
- * @throws when request fails, or returned token response is invalid
+ * @throws An `Error` with `message` set to an entry in {@link OidcError},
+ *      when the request fails, or the returned token response is invalid.
  */
 export const completeAuthorizationCodeGrant = async (
     code: string,

src/oidc/error.ts

@@ -14,6 +14,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+/**
+ * Errors expected to be encountered during OIDC discovery, client registration, and authentication.
+ * Not intended to be displayed directly to the user.
+ */
 export enum OidcError {
     NotSupported = "OIDC authentication not supported",
     Misconfigured = "OIDC is misconfigured",

src/oidc/index.ts

@@ -14,4 +14,9 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+export * from "./authorize";
+export * from "./discovery";
+export * from "./error";
+export * from "./register";
 export * from "./tokenRefresher";
+export * from "./validate";

src/oidc/register.ts

@@ -34,7 +34,8 @@ export type OidcRegistrationClientMetadata = {
  * @param registrationEndpoint - URL as returned from issuer ./well-known/openid-configuration
  * @param clientMetadata - registration metadata
  * @returns resolves to the registered client id when registration is successful
- * @throws when registration request fails, or response is invalid
+ * @throws An `Error` with `message` set to an entry in {@link OidcError},
+ *      when the registration request fails, or the response is invalid.
  */
 const doRegistration = async (
     registrationEndpoint: string,

src/rendezvous/channels/MSC3903ECDHv2RendezvousChannel.ts

@@ -25,7 +25,7 @@ import {
     RendezvousTransport,
     RendezvousFailureReason,
 } from "..";
-import { encodeUnpaddedBase64, decodeBase64 } from "../../crypto/olmlib";
+import { encodeUnpaddedBase64, decodeBase64 } from "../../base64";
 import { crypto, subtleCrypto, TextEncoder } from "../../crypto/crypto";
 import { generateDecimalSas } from "../../crypto/verification/SASDecimal";
 import { UnstableValue } from "../../NamespacedValue";

src/rust-crypto/OutgoingRequestProcessor.ts

@@ -31,6 +31,7 @@ import { IHttpOpts, MatrixHttpApi, Method } from "../http-api";
 import { QueryDict } from "../utils";
 import { IAuthDict, UIAuthCallback } from "../interactive-auth";
 import { UIAResponse } from "../@types/uia";
+import { ToDeviceMessageId } from "../@types/event";
 
 /**
  * Common interface for all the request types returned by `OlmMachine.outgoingRequests`.
@@ -60,7 +61,10 @@ export class OutgoingRequestProcessor {
         private readonly http: MatrixHttpApi<IHttpOpts & { onlyData: true }>,
     ) {}
 
-    public async makeOutgoingRequest<T>(msg: OutgoingRequest, uiaCallback?: UIAuthCallback<T>): Promise<void> {
+    public async makeOutgoingRequest<T>(
+        msg: OutgoingRequest | SigningKeysUploadRequest,
+        uiaCallback?: UIAuthCallback<T>,
+    ): Promise<void> {
         let resp: string;
 
         /* refer https://docs.rs/matrix-sdk-crypto/0.6.0/matrix_sdk_crypto/requests/enum.OutgoingRequests.html
@@ -82,23 +86,22 @@ export class OutgoingRequestProcessor {
                 msg.body,
             );
         } else if (msg instanceof ToDeviceRequest) {
-            const path =
-                `/_matrix/client/v3/sendToDevice/${encodeURIComponent(msg.event_type)}/` +
-                encodeURIComponent(msg.txn_id);
-            resp = await this.rawJsonRequest(Method.Put, path, {}, msg.body);
+            resp = await this.sendToDeviceRequest(msg);
         } else if (msg instanceof RoomMessageRequest) {
             const path =
                 `/_matrix/client/v3/rooms/${encodeURIComponent(msg.room_id)}/send/` +
                 `${encodeURIComponent(msg.event_type)}/${encodeURIComponent(msg.txn_id)}`;
             resp = await this.rawJsonRequest(Method.Put, path, {}, msg.body);
         } else if (msg instanceof SigningKeysUploadRequest) {
-            resp = await this.makeRequestWithUIA(
+            await this.makeRequestWithUIA(
                 Method.Post,
                 "/_matrix/client/v3/keys/device_signing/upload",
                 {},
                 msg.body,
                 uiaCallback,
             );
+            // SigningKeysUploadRequest does not implement OutgoingRequest and does not need to be marked as sent.
+            return;
         } else {
             logger.warn("Unsupported outgoing message", Object.getPrototypeOf(msg));
             resp = "";
@@ -122,6 +125,34 @@ export class OutgoingRequestProcessor {
         }
     }
 
+    /**
+     * Send the HTTP request for a `ToDeviceRequest`
+     *
+     * @param request - request to send
+     * @returns JSON-serialized body of the response, if successful
+     */
+    private async sendToDeviceRequest(request: ToDeviceRequest): Promise<string> {
+        // a bit of extra logging, to help trace to-device messages through the system
+        const parsedBody: { messages: Record<string, Record<string, Record<string, any>>> } = JSON.parse(request.body);
+
+        const messageList = [];
+        for (const [userId, perUserMessages] of Object.entries(parsedBody.messages)) {
+            for (const [deviceId, message] of Object.entries(perUserMessages)) {
+                messageList.push(`${userId}/${deviceId} (msgid ${message[ToDeviceMessageId]})`);
+            }
+        }
+
+        logger.info(
+            `Sending batch of to-device messages. type=${request.event_type} txnid=${request.txn_id}`,
+            messageList,
+        );
+
+        const path =
+            `/_matrix/client/v3/sendToDevice/${encodeURIComponent(request.event_type)}/` +
+            encodeURIComponent(request.txn_id);
+        return await this.rawJsonRequest(Method.Put, path, {}, request.body);
+    }
+
     private async makeRequestWithUIA<T>(
         method: Method,
         path: string,

src/rust-crypto/RoomEncryptor.ts

@@ -14,7 +14,15 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { EncryptionSettings, OlmMachine, RoomId, UserId } from "@matrix-org/matrix-sdk-crypto-wasm";
+import {
+    EncryptionAlgorithm,
+    EncryptionSettings,
+    OlmMachine,
+    RoomId,
+    UserId,
+    HistoryVisibility as RustHistoryVisibility,
+    ToDeviceRequest,
+} from "@matrix-org/matrix-sdk-crypto-wasm";
 
 import { EventType } from "../@types/event";
 import { IContent, MatrixEvent } from "../models/event";
@@ -23,6 +31,7 @@ import { Logger, logger } from "../logger";
 import { KeyClaimManager } from "./KeyClaimManager";
 import { RoomMember } from "../models/room-member";
 import { OutgoingRequestProcessor } from "./OutgoingRequestProcessor";
+import { HistoryVisibility } from "../@types/partials";
 
 /**
  * RoomEncryptor: responsible for encrypting messages to a given room
@@ -35,6 +44,7 @@ export class RoomEncryptor {
     /**
      * @param olmMachine - The rust-sdk's OlmMachine
      * @param keyClaimManager - Our KeyClaimManager, which manages the queue of one-time-key claim requests
+     * @param outgoingRequestProcessor - The OutgoingRequestProcessor, which sends outgoing requests
      * @param room - The room we want to encrypt for
      * @param encryptionSettings - body of the m.room.encryption event currently in force in this room
      */
@@ -83,8 +93,10 @@ export class RoomEncryptor {
      *
      * This ensures that we have a megolm session ready to use and that we have shared its key with all the devices
      * in the room.
+     *
+     * @param globalBlacklistUnverifiedDevices - When `true`, it will not send encrypted messages to unverified devices
      */
-    public async ensureEncryptionSession(): Promise<void> {
+    public async ensureEncryptionSession(globalBlacklistUnverifiedDevices: boolean): Promise<void> {
         if (this.encryptionSettings.algorithm !== "m.megolm.v1.aes-sha2") {
             throw new Error(
                 `Cannot encrypt in ${this.room.roomId} for unsupported algorithm '${this.encryptionSettings.algorithm}'`,
@@ -103,9 +115,28 @@ export class RoomEncryptor {
         this.prefixedLogger.debug("Sessions for users are ready; now sharing room key");
 
         const rustEncryptionSettings = new EncryptionSettings();
-        /* FIXME historyVisibility, rotation, etc */
+        rustEncryptionSettings.historyVisibility = toRustHistoryVisibility(this.room.getHistoryVisibility());
 
-        const shareMessages = await this.olmMachine.shareRoomKey(
+        // We only support megolm
+        rustEncryptionSettings.algorithm = EncryptionAlgorithm.MegolmV1AesSha2;
+
+        // We need to convert the rotation period from milliseconds to microseconds
+        // See https://spec.matrix.org/v1.8/client-server-api/#mroomencryption and
+        // https://matrix-org.github.io/matrix-rust-sdk-crypto-wasm/classes/EncryptionSettings.html#rotationPeriod
+        if (typeof this.encryptionSettings.rotation_period_ms === "number") {
+            rustEncryptionSettings.rotationPeriod = BigInt(this.encryptionSettings.rotation_period_ms * 1000);
+        }
+
+        if (typeof this.encryptionSettings.rotation_period_msgs === "number") {
+            rustEncryptionSettings.rotationPeriodMessages = BigInt(this.encryptionSettings.rotation_period_msgs);
+        }
+
+        // When this.room.getBlacklistUnverifiedDevices() === null, the global settings should be used
+        // See Room#getBlacklistUnverifiedDevices
+        rustEncryptionSettings.onlyAllowTrustedDevices =
+            this.room.getBlacklistUnverifiedDevices() ?? globalBlacklistUnverifiedDevices;
+
+        const shareMessages: ToDeviceRequest[] = await this.olmMachine.shareRoomKey(
             new RoomId(this.room.roomId),
             userList,
             rustEncryptionSettings,
@@ -134,9 +165,10 @@ export class RoomEncryptor {
      * then encrypt the event using the session.
      *
      * @param event - Event to be encrypted.
+     * @param globalBlacklistUnverifiedDevices - When `true`, it will not send encrypted messages to unverified devices
      */
-    public async encryptEvent(event: MatrixEvent): Promise<void> {
-        await this.ensureEncryptionSession();
+    public async encryptEvent(event: MatrixEvent, globalBlacklistUnverifiedDevices: boolean): Promise<void> {
+        await this.ensureEncryptionSession(globalBlacklistUnverifiedDevices);
 
         const encryptedContent = await this.olmMachine.encryptRoomEvent(
             new RoomId(this.room.roomId),
@@ -152,3 +184,21 @@ export class RoomEncryptor {
         );
     }
 }
+
+/**
+ * Convert a HistoryVisibility to a RustHistoryVisibility
+ * @param visibility - HistoryVisibility enum
+ * @returns a RustHistoryVisibility enum
+ */
+export function toRustHistoryVisibility(visibility: HistoryVisibility): RustHistoryVisibility {
+    switch (visibility) {
+        case HistoryVisibility.Invited:
+            return RustHistoryVisibility.Invited;
+        case HistoryVisibility.Joined:
+            return RustHistoryVisibility.Joined;
+        case HistoryVisibility.Shared:
+            return RustHistoryVisibility.Shared;
+        case HistoryVisibility.WorldReadable:
+            return RustHistoryVisibility.WorldReadable;
+    }
+}

src/rust-crypto/backup.ts

@@ -29,7 +29,7 @@ import { logger } from "../logger";
 import { ClientPrefix, IHttpOpts, MatrixError, MatrixHttpApi, Method } from "../http-api";
 import { CryptoEvent, IMegolmSessionData } from "../crypto";
 import { TypedEventEmitter } from "../models/typed-event-emitter";
-import { encodeUri } from "../utils";
+import { encodeUri, immediate } from "../utils";
 import { OutgoingRequestProcessor } from "./OutgoingRequestProcessor";
 import { sleep } from "../utils";
 import { BackupDecryptor } from "../common-crypto/CryptoBackend";
@@ -95,11 +95,9 @@ export class RustBackupManager extends TypedEventEmitter<RustBackupCryptoEvents,
         const signatureVerification: SignatureVerification = await this.olmMachine.verifyBackup(info);
 
         const backupKeys: RustSdkCryptoJs.BackupKeys = await this.olmMachine.getBackupKeys();
-        const pubKeyForSavedPrivateKey = backupKeys?.decryptionKey?.megolmV1PublicKey;
+        const decryptionKey = backupKeys?.decryptionKey;
         const backupMatchesSavedPrivateKey =
-            info.algorithm === pubKeyForSavedPrivateKey?.algorithm &&
-            (info.auth_data as Curve25519AuthData)?.public_key === pubKeyForSavedPrivateKey.publicKeyBase64;
-
+            !!decryptionKey && backupInfoMatchesBackupDecryptionKey(info, decryptionKey);
         return {
             matchesDecryptionKey: backupMatchesSavedPrivateKey,
             trusted: signatureVerification.trusted(),
@@ -124,6 +122,48 @@ export class RustBackupManager extends TypedEventEmitter<RustBackupCryptoEvents,
         }
         return this.keyBackupCheckInProgress;
     }
+
+    /**
+     * Handles a backup secret received event and store it if it matches the current backup version.
+     *
+     * @param secret - The secret as received from a `m.secert.send` event for secret `m.megolm_backup.v1`.
+     * @returns true if the secret is valid and has been stored, false otherwise.
+     */
+    public async handleBackupSecretReceived(secret: string): Promise<boolean> {
+        // Currently we only receive the decryption key without any key backup version. It is important to
+        // check that the secret is valid for the current version before storing it.
+        // We force a check to ensure to have the latest version. We also want to check that the backup is trusted
+        // as we don't want to store the secret if the backup is not trusted, and eventually import megolm keys later from an untrusted backup.
+        const backupCheck = await this.checkKeyBackupAndEnable(true);
+
+        if (!backupCheck?.backupInfo?.version || !backupCheck.trustInfo.trusted) {
+            // There is no server-side key backup, or the backup is not signed by a trusted cross-signing key or trusted own device.
+            // This decryption key is useless to us.
+            logger.warn("Received backup decryption key, but there is no trusted server-side key backup");
+            return false;
+        }
+
+        try {
+            const backupDecryptionKey = RustSdkCryptoJs.BackupDecryptionKey.fromBase64(secret);
+            const privateKeyMatches = backupInfoMatchesBackupDecryptionKey(backupCheck.backupInfo, backupDecryptionKey);
+            if (!privateKeyMatches) {
+                logger.debug(`onReceiveSecret: backup decryption key does not match current backup version`);
+                // just ignore the secret
+                return false;
+            }
+            logger.info(
+                `handleBackupSecretReceived: A valid backup decryption key has been received and stored in cache.`,
+            );
+
+            await this.olmMachine.saveBackupDecryptionKey(backupDecryptionKey, backupCheck.backupInfo.version);
+            return true;
+        } catch (e) {
+            logger.warn("handleBackupSecretReceived: Invalid backup decryption key", e);
+        }
+
+        return false;
+    }
+
     private keyBackupCheckInProgress: Promise<KeyBackupCheck | null> | null = null;
 
     /** Helper for `checkKeyBackup` */
@@ -379,6 +419,25 @@ export class RustBackupManager extends TypedEventEmitter<RustBackupCryptoEvents,
     }
 }
 
+/**
+ * Checks if the provided backup info matches the given private key.
+ *
+ * @param info - The backup info to check.
+ * @param backupDecryptionKey - The `BackupDecryptionKey` private key to check against.
+ * @returns `true` if the private key can decrypt the backup, `false` otherwise.
+ */
+function backupInfoMatchesBackupDecryptionKey(
+    info: KeyBackupInfo,
+    backupDecryptionKey: RustSdkCryptoJs.BackupDecryptionKey,
+): boolean {
+    if (info.algorithm !== "m.megolm_backup.v1.curve25519-aes-sha2") {
+        logger.warn("backupMatchesPrivateKey: Unsupported backup algorithm", info.algorithm);
+        return false;
+    }
+
+    return (info.auth_data as Curve25519AuthData)?.public_key === backupDecryptionKey.megolmV1PublicKey.publicKeyBase64;
+}
+
 /**
  * Implementation of {@link BackupDecryptor} for the rust crypto backend.
  */
@@ -401,7 +460,7 @@ export class RustBackupDecryptor implements BackupDecryptor {
         for (const [sessionId, sessionData] of Object.entries(ciphertexts)) {
             try {
                 const decrypted = JSON.parse(
-                    await this.decryptionKey.decryptV1(
+                    this.decryptionKey.decryptV1(
                         sessionData.session_data.ephemeral,
                         sessionData.session_data.mac,
                         sessionData.session_data.ciphertext,
@@ -409,6 +468,9 @@ export class RustBackupDecryptor implements BackupDecryptor {
                 );
                 decrypted.session_id = sessionId;
                 keys.push(decrypted);
+
+                // there might be lots of sessions, so don't hog the event loop
+                await immediate();
             } catch (e) {
                 logger.log("Failed to decrypt megolm session from backup", e, sessionData);
             }

src/rust-crypto/index.ts

@@ -54,7 +54,7 @@ export async function initRustCrypto(
     await RustSdkCryptoJs.initAsync();
 
     // enable tracing in the rust-sdk
-    new RustSdkCryptoJs.Tracing(RustSdkCryptoJs.LoggerLevel.Trace).turnOn();
+    new RustSdkCryptoJs.Tracing(RustSdkCryptoJs.LoggerLevel.Debug).turnOn();
 
     const u = new RustSdkCryptoJs.UserId(userId);
     const d = new RustSdkCryptoJs.DeviceId(deviceId);
@@ -75,6 +75,17 @@ export async function initRustCrypto(
         rustCrypto.onUserIdentityUpdated(userId),
     );
 
+    // Check if there are any key backup secrets pending processing. There may be multiple secrets to process if several devices have gossiped them.
+    // The `registerReceiveSecretCallback` function will only be triggered for new secrets. If the client is restarted before processing them, the secrets will need to be manually handled.
+    rustCrypto.checkSecrets("m.megolm_backup.v1");
+
+    // Register a callback to be notified when a new secret is received, as for now only the key backup secret is supported (the cross signing secrets are handled automatically by the OlmMachine)
+    await olmMachine.registerReceiveSecretCallback((name: string, _value: string) =>
+        // Instead of directly checking the secret value, we poll the inbox to get all values for that secret type.
+        // Once we have all the values, we can safely clear the secret inbox.
+        rustCrypto.checkSecrets(name),
+    );
+
     // Tell the OlmMachine to think about its outgoing requests before we hand control back to the application.
     //
     // This is primarily a fudge to get it to correctly populate the `users_for_key_query` list, so that future

src/rust-crypto/rust-crypto.ts

@@ -29,7 +29,7 @@ import { ClientPrefix, IHttpOpts, MatrixHttpApi, Method } from "../http-api";
 import { RoomEncryptor } from "./RoomEncryptor";
 import { OutgoingRequest, OutgoingRequestProcessor } from "./OutgoingRequestProcessor";
 import { KeyClaimManager } from "./KeyClaimManager";
-import { MapWithDefault, encodeUri } from "../utils";
+import { encodeUri, MapWithDefault } from "../utils";
 import {
     BackupTrustInfo,
     BootstrapCrossSigningOpts,
@@ -70,7 +70,7 @@ import { TypedReEmitter } from "../ReEmitter";
 import { randomString } from "../randomstring";
 import { ClientStoppedError } from "../errors";
 import { ISignatures } from "../@types/signed";
-import { encodeBase64 } from "../common-crypto/base64";
+import { encodeBase64 } from "../base64";
 import { DecryptionError } from "../crypto/algorithms";
 
 const ALL_VERIFICATION_METHODS = ["m.sas.v1", "m.qr_code.scan.v1", "m.qr_code.show.v1", "m.reciprocate.v1"];
@@ -88,7 +88,6 @@ const KEY_BACKUP_CHECK_RATE_LIMIT = 5000; // ms
  * @internal
  */
 export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEventMap> implements CryptoBackend {
-    public globalErrorOnUnknownDevices = false;
     private _trustCrossSignedDevices = true;
 
     /** whether {@link stop} has been called */
@@ -161,43 +160,72 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
     }
 
     /**
-     * Attempts to retrieve a session from a key backup, if enough time
+     * Starts an attempt to retrieve a session from a key backup, if enough time
      * has elapsed since the last check for this session id.
+     *
+     * If a backup is found, it is decrypted and imported.
+     *
+     * @param targetRoomId - ID of the room that the session is used in.
+     * @param targetSessionId - ID of the session for which to check backup.
      */
-    public async queryKeyBackupRateLimited(targetRoomId: string, targetSessionId: string): Promise<void> {
-        const backupKeys: RustSdkCryptoJs.BackupKeys = await this.olmMachine.getBackupKeys();
-        if (!backupKeys.decryptionKey) return;
-        const version = backupKeys.backupVersion;
-
+    public startQueryKeyBackupRateLimited(targetRoomId: string, targetSessionId: string): void {
         const now = new Date().getTime();
-        if (
-            !this.sessionLastCheckAttemptedTime[targetSessionId!] ||
-            now - this.sessionLastCheckAttemptedTime[targetSessionId!] > KEY_BACKUP_CHECK_RATE_LIMIT
-        ) {
+        const lastCheck = this.sessionLastCheckAttemptedTime[targetSessionId];
+        if (!lastCheck || now - lastCheck > KEY_BACKUP_CHECK_RATE_LIMIT) {
             this.sessionLastCheckAttemptedTime[targetSessionId!] = now;
-
-            const path = encodeUri("/room_keys/keys/$roomId/$sessionId", {
-                $roomId: targetRoomId,
-                $sessionId: targetSessionId,
+            this.queryKeyBackup(targetRoomId, targetSessionId).catch((e) => {
+                this.logger.error(`Unhandled error while checking key backup for session ${targetSessionId}`, e);
             });
+        } else {
+            const lastCheckStr = new Date(lastCheck).toISOString();
+            this.logger.debug(
+                `Not checking key backup for session ${targetSessionId} (last checked at ${lastCheckStr})`,
+            );
+        }
+    }
 
-            const res = await this.http.authedRequest<KeyBackupSession>(Method.Get, path, { version }, undefined, {
+    /**
+     * Helper for {@link RustCrypto#startQueryKeyBackupRateLimited}.
+     *
+     * Requests the backup and imports it. Doesn't do any rate-limiting.
+     *
+     * @param targetRoomId - ID of the room that the session is used in.
+     * @param targetSessionId - ID of the session for which to check backup.
+     */
+    private async queryKeyBackup(targetRoomId: string, targetSessionId: string): Promise<void> {
+        const backupKeys: RustSdkCryptoJs.BackupKeys = await this.olmMachine.getBackupKeys();
+        if (!backupKeys.decryptionKey) {
+            this.logger.debug(`Not checking key backup for session ${targetSessionId} (no decryption key)`);
+            return;
+        }
+
+        this.logger.debug(`Checking key backup for session ${targetSessionId}`);
+
+        const version = backupKeys.backupVersion;
+        const path = encodeUri("/room_keys/keys/$roomId/$sessionId", {
+            $roomId: targetRoomId,
+            $sessionId: targetSessionId,
+        });
+
+        let res: KeyBackupSession;
+        try {
+            res = await this.http.authedRequest<KeyBackupSession>(Method.Get, path, { version }, undefined, {
                 prefix: ClientPrefix.V3,
             });
-
-            if (this.stopped) return;
-
-            const backupDecryptor = new RustBackupDecryptor(backupKeys.decryptionKey);
-            if (res) {
-                const sessionsToImport: Record<string, KeyBackupSession> = {};
-                sessionsToImport[targetSessionId] = res;
-                const keys = await backupDecryptor.decryptSessions(sessionsToImport);
-                for (const k of keys) {
-                    k.room_id = targetRoomId!;
-                }
-                await this.importRoomKeys(keys);
-            }
+        } catch (e) {
+            this.logger.info(`No luck requesting key backup for session ${targetSessionId}: ${e}`);
+            return;
         }
+
+        if (this.stopped) return;
+
+        const backupDecryptor = new RustBackupDecryptor(backupKeys.decryptionKey);
+        const sessionsToImport: Record<string, KeyBackupSession> = { [targetSessionId]: res };
+        const keys = await backupDecryptor.decryptSessions(sessionsToImport);
+        for (const k of keys) {
+            k.room_id = targetRoomId;
+        }
+        await this.importRoomKeys(keys);
     }
 
     /**
@@ -220,6 +248,15 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
     //
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
+    public set globalErrorOnUnknownDevices(_v: boolean) {
+        // Not implemented for rust crypto.
+    }
+
+    public get globalErrorOnUnknownDevices(): boolean {
+        // Not implemented for rust crypto.
+        return false;
+    }
+
     public stop(): void {
         // stop() may be called multiple times, but attempting to close() the OlmMachine twice
         // will cause an error.
@@ -245,7 +282,7 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
             throw new Error(`Cannot encrypt event in unconfigured room ${roomId}`);
         }
 
-        await encryptor.encryptEvent(event);
+        await encryptor.encryptEvent(event, this.globalBlacklistUnverifiedDevices);
     }
 
     public async decryptEvent(event: MatrixEvent): Promise<IEventDecryptionResult> {
@@ -267,8 +304,6 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
      * @param event - event to inspect
      */
     public getEventEncryptionInfo(event: MatrixEvent): IEncryptedEventInfo {
-        // TODO: make this work properly. Or better, replace it.
-
         const ret: Partial<IEncryptedEventInfo> = {};
 
         ret.senderKey = event.getSenderKey() ?? undefined;
@@ -329,11 +364,19 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
 
     public globalBlacklistUnverifiedDevices = false;
 
+    /**
+     * Implementation of {@link CryptoApi#getVersion}.
+     */
+    public getVersion(): string {
+        const versions = RustSdkCryptoJs.getVersions();
+        return `Rust SDK ${versions.matrix_sdk_crypto} (${versions.git_sha}), Vodozemac ${versions.vodozemac}`;
+    }
+
     public prepareToEncrypt(room: Room): void {
         const encryptor = this.roomEncryptors[room.roomId];
 
         if (encryptor) {
-            encryptor.ensureEncryptionSession();
+            encryptor.ensureEncryptionSession(this.globalBlacklistUnverifiedDevices);
         }
     }
 
@@ -1357,6 +1400,51 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         }
     }
 
+    /**
+     * Handles secret received from the rust secret inbox.
+     *
+     * The gossipped secrets are received using the `m.secret.send` event type
+     * and are guaranteed to have been received over a 1-to-1 Olm
+     * Session from a verified device.
+     *
+     * The only secret currently handled in this way is `m.megolm_backup.v1`.
+     *
+     * @param name - the secret name
+     * @param value - the secret value
+     */
+    private async handleSecretReceived(name: string, value: string): Promise<boolean> {
+        this.logger.debug(`onReceiveSecret: Received secret ${name}`);
+        if (name === "m.megolm_backup.v1") {
+            return await this.backupManager.handleBackupSecretReceived(value);
+            // XXX at this point we should probably try to download the backup and import the keys,
+            // or at least retry for the current decryption failures?
+            // Maybe add some signaling when a new secret is received, and let clients handle it?
+            // as it's where the restore from backup APIs are exposed.
+        }
+        return false;
+    }
+
+    /**
+     * Called when a new secret is received in the rust secret inbox.
+     *
+     * Will poll the secret inbox and handle the secrets received.
+     *
+     * @param name - The name of the secret received.
+     */
+    public async checkSecrets(name: string): Promise<void> {
+        const pendingValues: string[] = await this.olmMachine.getSecretsFromInbox(name);
+        for (const value of pendingValues) {
+            if (await this.handleSecretReceived(name, value)) {
+                // If we have a valid secret for that name there is no point of processing the other secrets values.
+                // It's probably the same secret shared by another device.
+                break;
+            }
+        }
+
+        // Important to call this after handling the secrets as good hygiene.
+        await this.olmMachine.deleteSecretsFromInbox(name);
+    }
+
     /**
      * Handle a live event received via /sync.
      * See {@link ClientEventHandlerMap#event}
@@ -1492,7 +1580,6 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
                 // if `this.outgoingRequestLoop()` was called while `OlmMachine.outgoingRequests()` was running.
                 this.outgoingRequestLoopOneMoreLoop = false;
 
-                this.logger.debug("Calling OlmMachine.outgoingRequests()");
                 const outgoingRequests: Object[] = await this.olmMachine.outgoingRequests();
 
                 if (this.stopped) {
@@ -1575,7 +1662,10 @@ class EventDecryptor {
                                 session: content.sender_key + "|" + content.session_id,
                             },
                         );
-                        this.crypto.queryKeyBackupRateLimited(event.getRoomId()!, event.getWireContent().session_id!);
+                        this.crypto.startQueryKeyBackupRateLimited(
+                            event.getRoomId()!,
+                            event.getWireContent().session_id!,
+                        );
                         break;
                     }
                     case RustSdkCryptoJs.DecryptionErrorCode.UnknownMessageIndex: {
@@ -1586,7 +1676,10 @@ class EventDecryptor {
                                 session: content.sender_key + "|" + content.session_id,
                             },
                         );
-                        this.crypto.queryKeyBackupRateLimited(event.getRoomId()!, event.getWireContent().session_id!);
+                        this.crypto.startQueryKeyBackupRateLimited(
+                            event.getRoomId()!,
+                            event.getWireContent().session_id!,
+                        );
                         break;
                     }
                     // We don't map MismatchedIdentityKeys for now, as there is no equivalent in legacy.
@@ -1605,11 +1698,16 @@ class EventDecryptor {
     }
 
     public async getEncryptionInfoForEvent(event: MatrixEvent): Promise<EventEncryptionInfo | null> {
-        if (!event.getClearContent()) {
+        if (!event.getClearContent() || event.isDecryptionFailure()) {
             // not successfully decrypted
             return null;
         }
 
+        // special-case outgoing events, which the rust crypto-sdk will barf on
+        if (event.status !== null) {
+            return { shieldColour: EventShieldColour.NONE, shieldReason: null };
+        }
+
         const encryptionInfo = await this.olmMachine.getRoomEventEncryptionInfo(
             stringifyEvent(event),
             new RustSdkCryptoJs.RoomId(event.getRoomId()!),

src/store/index.ts

@@ -32,6 +32,8 @@ export interface ISavedSync {
     accountData: IMinimalEvent[];
 }
 
+export type UserCreator = (userId: string) => User;
+
 /**
  * A store for most of the data js-sdk needs to store, apart from crypto data
  */
@@ -62,6 +64,12 @@ export interface IStore {
      */
     storeRoom(room: Room): void;
 
+    /**
+     * Set the user creator which is used for creating User objects
+     * @param creator - A callback that accepts an user-id and returns an User object
+     */
+    setUserCreator(creator: UserCreator): void;
+
     /**
      * Retrieve a room by its' room ID.
      * @param roomId - The room ID.

src/store/indexeddb-local-backend.ts

@@ -191,7 +191,6 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
                 this.db?.close(); // this does not call onclose
                 this.disconnected = true;
                 this.db = undefined;
-                onClose?.();
             };
             this.db.onclose = (): void => {
                 this.disconnected = true;

src/store/indexeddb.ts

@@ -19,7 +19,6 @@ limitations under the License.
 import { MemoryStore, IOpts as IBaseOpts } from "./memory";
 import { LocalIndexedDBStoreBackend } from "./indexeddb-local-backend";
 import { RemoteIndexedDBStoreBackend } from "./indexeddb-remote-backend";
-import { User } from "../models/user";
 import { IEvent, MatrixEvent } from "../models/event";
 import { logger } from "../logger";
 import { ISavedSync } from "./index";
@@ -140,7 +139,10 @@ export class IndexedDBStore extends MemoryStore {
             .then((userPresenceEvents) => {
                 logger.log(`IndexedDBStore.startup: processing presence events`);
                 userPresenceEvents.forEach(([userId, rawEvent]) => {
-                    const u = new User(userId);
+                    if (!this.createUser) {
+                        throw new Error("createUser is undefined, it should be set with setUserCreator()!");
+                    }
+                    const u = this.createUser(userId);
                     if (rawEvent) {
                         u.setPresenceEvent(new MatrixEvent(rawEvent));
                     }

src/store/memory.ts

@@ -25,7 +25,7 @@ import { IEvent, MatrixEvent } from "../models/event";
 import { RoomState, RoomStateEvent } from "../models/room-state";
 import { RoomMember } from "../models/room-member";
 import { Filter } from "../filter";
-import { ISavedSync, IStore } from "./index";
+import { ISavedSync, IStore, UserCreator } from "./index";
 import { RoomSummary } from "../models/room-summary";
 import { ISyncResponse } from "../sync-accumulator";
 import { IStateEventWithRoomId } from "../@types/search";
@@ -63,6 +63,7 @@ export class MemoryStore implements IStore {
     private clientOptions?: IStoredClientOpts;
     private pendingToDeviceBatches: IndexedToDeviceBatch[] = [];
     private nextToDeviceBatchId = 0;
+    protected createUser?: UserCreator;
 
     /**
      * Construct a new in-memory data store for the Matrix Client.
@@ -108,6 +109,10 @@ export class MemoryStore implements IStore {
         });
     }
 
+    public setUserCreator(creator: UserCreator): void {
+        this.createUser = creator;
+    }
+
     /**
      * Called when a room member in a room being tracked by this store has been
      * updated.
@@ -119,7 +124,7 @@ export class MemoryStore implements IStore {
             return;
         }
 
-        const user = this.users[member.userId] || new User(member.userId);
+        const user = this.users[member.userId] || this.createUser?.(member.userId);
         if (member.name) {
             user.setDisplayName(member.name);
             if (member.events.member) {

src/store/stub.ts

@@ -23,7 +23,7 @@ import { Room } from "../models/room";
 import { User } from "../models/user";
 import { IEvent, MatrixEvent } from "../models/event";
 import { Filter } from "../filter";
-import { ISavedSync, IStore } from "./index";
+import { ISavedSync, IStore, UserCreator } from "./index";
 import { RoomSummary } from "../models/room-summary";
 import { ISyncResponse } from "../sync-accumulator";
 import { IStateEventWithRoomId } from "../@types/search";
@@ -117,6 +117,13 @@ export class StubStore implements IStore {
         return [];
     }
 
+    /**
+     * No-op.
+     */
+    public setUserCreator(creator: UserCreator): void {
+        return;
+    }
+
     /**
      * Store events for a room.
      * @param room - The room to store events for.

src/sync.ts

@@ -26,7 +26,7 @@ limitations under the License.
 import { Optional } from "matrix-events-sdk";
 
 import type { SyncCryptoCallbacks } from "./common-crypto/CryptoBackend";
-import { User, UserEvent } from "./models/user";
+import { User } from "./models/user";
 import { NotificationCountType, Room, RoomEvent } from "./models/room";
 import { deepCopy, defer, IDeferred, noUnsafeEventProps, promiseMapSeries, unsafeProp } from "./utils";
 import { Filter } from "./filter";
@@ -431,7 +431,7 @@ export class SyncApi {
                     if (user) {
                         user.setPresenceEvent(presenceEvent);
                     } else {
-                        user = createNewUser(client, presenceEvent.getContent().user_id);
+                        user = User.createUser(presenceEvent.getContent().user_id, client);
                         user.setPresenceEvent(presenceEvent);
                         client.store.storeUser(user);
                     }
@@ -530,7 +530,7 @@ export class SyncApi {
                             if (user) {
                                 user.setPresenceEvent(presenceEvent);
                             } else {
-                                user = createNewUser(this.client, presenceEvent.getContent().user_id);
+                                user = User.createUser(presenceEvent.getContent().user_id, this.client);
                                 user.setPresenceEvent(presenceEvent);
                                 this.client.store.storeUser(user);
                             }
@@ -1150,7 +1150,7 @@ export class SyncApi {
                     if (user) {
                         user.setPresenceEvent(presenceEvent);
                     } else {
-                        user = createNewUser(client, presenceEvent.getSender()!);
+                        user = User.createUser(presenceEvent.getSender()!, client);
                         user.setPresenceEvent(presenceEvent);
                         client.store.storeUser(user);
                     }
@@ -1893,18 +1893,6 @@ export class SyncApi {
     };
 }
 
-function createNewUser(client: MatrixClient, userId: string): User {
-    const user = new User(userId);
-    client.reEmitter.reEmit(user, [
-        UserEvent.AvatarUrl,
-        UserEvent.DisplayName,
-        UserEvent.Presence,
-        UserEvent.CurrentlyActive,
-        UserEvent.LastPresenceTs,
-    ]);
-    return user;
-}
-
 // /!\ This function is not intended for public use! It's only exported from
 // here in order to share some common logic with sliding-sync-sdk.ts.
 export function _createAndReEmitRoom(client: MatrixClient, roomId: string, opts: Partial<IStoredClientOpts>): Room {