Remove the ability to skip device verification during login

src/DeviceListener.ts

@@ -46,6 +46,7 @@ import { UIFeature } from "./settings/UIFeature";
 import { isBulkUnverifiedDeviceReminderSnoozed } from "./utils/device/snoozeBulkUnverifiedDeviceReminder";
 import { getUserDeviceIds } from "./utils/crypto/deviceInfo";
 import { asyncSomeParallel } from "./utils/arrays.ts";
+import { doesServerSupportCrossSigning } from "./utils/crypto/doesServerSupportCrossSigning";
 
 const KEY_BACKUP_POLL_INTERVAL = 5 * 60 * 1000;
 
@@ -318,8 +319,7 @@ export default class DeviceListener {
 
         const cli = this.client;
 
-        // cross-signing support was added to Matrix in MSC1756, which landed in spec v1.1
-        if (!(await cli.isVersionSupported("v1.1"))) {
+        if (!(await doesServerSupportCrossSigning(cli))) {
             logSpan.debug("cross-signing not supported");
             return;
         }

src/components/structures/MatrixChat.tsx

@@ -140,6 +140,7 @@ import { ShareFormat, type SharePayload } from "../../dispatcher/payloads/ShareP
 import Markdown from "../../Markdown";
 import { sanitizeHtmlParams } from "../../Linkify";
 import { isOnlyAdmin } from "../../utils/membership";
+import { doesServerSupportCrossSigning } from "../../utils/crypto/doesServerSupportCrossSigning";
 
 // legacy export
 export { default as Views } from "../../Views";
@@ -424,10 +425,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
             } else {
                 this.setStateForNewView({ view: Views.COMPLETE_SECURITY });
             }
-        } else if (
-            (await cli.doesServerSupportUnstableFeature("org.matrix.e2e_cross_signing")) &&
-            !(await shouldSkipSetupEncryption(cli))
-        ) {
+        } else if ((await doesServerSupportCrossSigning(cli)) && !(await shouldSkipSetupEncryption(cli))) {
             // if cross-signing is not yet set up, do so now if possible.
             InitialCryptoSetupStore.sharedInstance().startInitialCryptoSetup(
                 cli,

src/components/viewmodels/right_panel/user_info/UserInfoHeaderVerificationViewModel.tsx

@@ -12,6 +12,7 @@ import MatrixClientContext from "../../../../contexts/MatrixClientContext";
 import { type IDevice } from "../../../views/right_panel/UserInfo";
 import { useAsyncMemo } from "../../../../hooks/useAsyncMemo";
 import { verifyUser } from "../../../../verification";
+import { doesServerSupportCrossSigning } from "../../../../utils/crypto/doesServerSupportCrossSigning";
 
 export interface UserInfoVerificationSectionState {
     /**
@@ -32,7 +33,7 @@ export interface UserInfoVerificationSectionState {
 const useHomeserverSupportsCrossSigning = (cli: MatrixClient): boolean => {
     return useAsyncMemo<boolean>(
         async () => {
-            return cli.doesServerSupportUnstableFeature("org.matrix.e2e_cross_signing");
+            return doesServerSupportCrossSigning(cli);
         },
         [cli],
         false,

src/utils/crypto/doesServerSupportCrossSigning.ts

@@ -0,0 +1,19 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import { type MatrixClient } from "matrix-js-sdk/src/matrix";
+
+/**
+ * If the server supports cross-signing.
+ */
+export async function doesServerSupportCrossSigning(cli: MatrixClient): Promise<boolean> {
+    // cross-signing support was added to Matrix in MSC1756, which landed in spec v1.1
+    return (
+        (await cli.isVersionSupported("v1.1")) ||
+        (await cli.doesServerSupportUnstableFeature("org.matrix.e2e_cross_signing"))
+    );
+}

test/unit-tests/components/views/right_panel/UserInfo-test.tsx

@@ -118,6 +118,7 @@ beforeEach(() => {
         on: jest.fn(),
         off: jest.fn(),
         isSynapseAdministrator: jest.fn().mockResolvedValue(false),
+        isVersionSupported: jest.fn().mockResolvedValue(false),
         doesServerSupportUnstableFeature: jest.fn().mockReturnValue(false),
         doesServerSupportExtendedProfiles: jest.fn().mockResolvedValue(false),
         getExtendedProfileProperty: jest.fn().mockRejectedValue(new Error("Not supported")),