Fix a fresh login creating a new key backup (#12106)

Co-authored-by: Richard van der Hoff <[email protected]>
Co-authored-by: Valere <[email protected]>
fix repeated requests to enter 4S key during cross-signing reset (#12059)

Author: 3 people

playwright/e2e/crypto/backups.spec.ts

@@ -212,6 +212,43 @@ test.describe("Cryptography", function () {
         });
     }
 
+    test("Can reset cross-signing keys", async ({ page, app, user: aliceCredentials }) => {
+        const secretStorageKey = await enableKeyBackup(app);
+
+        // Fetch the current cross-signing keys
+        async function fetchMasterKey() {
+            return await test.step("Fetch master key from server", async () => {
+                const k = await app.client.evaluate(async (cli) => {
+                    const userId = cli.getUserId();
+                    const keys = await cli.downloadKeysForUsers([userId]);
+                    return Object.values(keys.master_keys[userId].keys)[0];
+                });
+                console.log(`fetchMasterKey: ${k}`);
+                return k;
+            });
+        }
+        const masterKey1 = await fetchMasterKey();
+
+        // Find the "reset cross signing" button, and click it
+        await app.settings.openUserSettings("Security & Privacy");
+        await page.locator("div.mx_CrossSigningPanel_buttonRow").getByRole("button", { name: "Reset" }).click();
+
+        // Confirm
+        await page.getByRole("button", { name: "Clear cross-signing keys" }).click();
+
+        // Enter the 4S key
+        await page.getByPlaceholder("Security Key").fill(secretStorageKey);
+        await page.getByRole("button", { name: "Continue" }).click();
+
+        await expect(async () => {
+            const masterKey2 = await fetchMasterKey();
+            expect(masterKey1).not.toEqual(masterKey2);
+        }).toPass();
+
+        // The dialog should have gone away
+        await expect(page.locator(".mx_Dialog")).toHaveCount(1);
+    });
+
     test("creating a DM should work, being e2e-encrypted / user verification", async ({
         page,
         app,

playwright/e2e/crypto/crypto.spec.ts

@@ -103,12 +103,35 @@ export async function checkDeviceIsCrossSigned(app: ElementAppPage): Promise<voi
 }
 
 /**
- * Check that the current device is connected to the key backup.
+ * Check that the current device is connected to the expected key backup.
+ * Also checks that the decryption key is known and cached locally.
+ *
+ * @param page - the page to check
+ * @param expectedBackupVersion - the version of the backup we expect to be connected to.
+ * @param checkBackupKeyInCache - whether to check that the backup key is cached locally.
  */
-export async function checkDeviceIsConnectedKeyBackup(page: Page) {
+export async function checkDeviceIsConnectedKeyBackup(
+    page: Page,
+    expectedBackupVersion: string,
+    checkBackupKeyInCache: boolean,
+): Promise<void> {
     await page.getByRole("button", { name: "User menu" }).click();
     await page.locator(".mx_UserMenu_contextMenu").getByRole("menuitem", { name: "Security & Privacy" }).click();
     await expect(page.locator(".mx_Dialog").getByRole("button", { name: "Restore from Backup" })).toBeVisible();
+
+    // expand the advanced section to see the active version in the reports
+    await page.locator(".mx_SecureBackupPanel_advanced").locator("..").click();
+
+    if (checkBackupKeyInCache) {
+        const cacheDecryptionKeyStatusElement = page.locator(".mx_SecureBackupPanel_statusList tr:nth-child(2) td");
+        await expect(cacheDecryptionKeyStatusElement).toHaveText("cached locally, well formed");
+    }
+
+    await expect(page.locator(".mx_SecureBackupPanel_statusList tr:nth-child(5) td")).toHaveText(
+        expectedBackupVersion + " (Algorithm: m.megolm_backup.v1.curve25519-aes-sha2)",
+    );
+
+    await expect(page.locator(".mx_SecureBackupPanel_statusList tr:nth-child(6) td")).toHaveText(expectedBackupVersion);
 }
 
 /**

playwright/e2e/crypto/utils.ts

@@ -33,6 +33,9 @@ import { Bot } from "../../pages/bot";
 test.describe("Device verification", () => {
     let aliceBotClient: Bot;
 
+    /** The backup version that was set up by the bot client. */
+    let expectedBackupVersion: string;
+
     test.beforeEach(async ({ page, homeserver, credentials }) => {
         // Visit the login page of the app, to load the matrix sdk
         await page.goto("/#/login");
@@ -49,9 +52,13 @@ test.describe("Device verification", () => {
             bootstrapSecretStorage: true,
         });
         aliceBotClient.setCredentials(credentials);
-        await aliceBotClient.prepareClient();
+        const mxClientHandle = await aliceBotClient.prepareClient();
 
         await page.waitForTimeout(20000);
+
+        expectedBackupVersion = await mxClientHandle.evaluate(async (mxClient) => {
+            return await mxClient.getCrypto()!.getActiveSessionBackupVersion();
+        });
     });
 
     // Click the "Verify with another device" button, and have the bot client auto-accept it.
@@ -87,7 +94,9 @@ test.describe("Device verification", () => {
         await checkDeviceIsCrossSigned(app);
 
         // Check that the current device is connected to key backup
-        await checkDeviceIsConnectedKeyBackup(page);
+        // For now we don't check that the backup key is in cache because it's a bit flaky,
+        // as we need to wait for the secret gossiping to happen and the settings dialog doesn't refresh automatically.
+        await checkDeviceIsConnectedKeyBackup(page, expectedBackupVersion, false);
     });
 
     test("Verify device with QR code during login", async ({ page, app, credentials, homeserver }) => {
@@ -130,7 +139,9 @@ test.describe("Device verification", () => {
         await checkDeviceIsCrossSigned(app);
 
         // Check that the current device is connected to key backup
-        await checkDeviceIsConnectedKeyBackup(page);
+        // For now we don't check that the backup key is in cache because it's a bit flaky,
+        // as we need to wait for the secret gossiping to happen and the settings dialog doesn't refresh automatically.
+        await checkDeviceIsConnectedKeyBackup(page, expectedBackupVersion, false);
     });
 
     test("Verify device with Security Phrase during login", async ({ page, app, credentials, homeserver }) => {
@@ -150,7 +161,8 @@ test.describe("Device verification", () => {
         await checkDeviceIsCrossSigned(app);
 
         // Check that the current device is connected to key backup
-        await checkDeviceIsConnectedKeyBackup(page);
+        // The backup decryption key should be in cache also, as we got it directly from the 4S
+        await checkDeviceIsConnectedKeyBackup(page, expectedBackupVersion, true);
     });
 
     test("Verify device with Security Key during login", async ({ page, app, credentials, homeserver }) => {
@@ -172,7 +184,8 @@ test.describe("Device verification", () => {
         await checkDeviceIsCrossSigned(app);
 
         // Check that the current device is connected to key backup
-        await checkDeviceIsConnectedKeyBackup(page);
+        // The backup decryption key should be in cache also, as we got it directly from the 4S
+        await checkDeviceIsConnectedKeyBackup(page, expectedBackupVersion, true);
     });
 
     test("Handle incoming verification request with SAS", async ({ page, credentials, homeserver, toasts }) => {

playwright/e2e/crypto/verification.spec.ts

@@ -260,7 +260,3 @@ export const expect = baseExpect.extend({
         return { pass: true, message: () => "", name: "toMatchScreenshot" };
     },
 });
-
-test.use({
-    permissions: ["clipboard-read"],
-});

playwright/element-web-test.ts

@@ -51,19 +51,6 @@ export class ElementAppPage {
         return this.settings.closeDialog();
     }
 
-    public async getClipboard(): Promise<string> {
-        return await this.page.evaluate(() => navigator.clipboard.readText());
-    }
-
-    /**
-     * Find an open dialog by its title
-     */
-    public async getDialogByTitle(title: string, timeout = 5000): Promise<Locator> {
-        const dialog = this.page.locator(".mx_Dialog");
-        await dialog.getByRole("heading", { name: title }).waitFor({ timeout });
-        return dialog;
-    }
-
     /**
      * Opens the given room by name. The room must be visible in the
      * room list, but the room list may be folded horizontally, and the

playwright/pages/ElementAppPage.ts

@@ -299,6 +299,28 @@ export async function promptForBackupPassphrase(): Promise<Uint8Array> {
     return key;
 }
 
+/**
+ * Carry out an operation that may require multiple accesses to secret storage, caching the key.
+ *
+ * Use this helper to wrap an operation that may require multiple accesses to secret storage; the user will be prompted
+ * to enter the 4S key or passphrase on the first access, and the key will be cached for the rest of the operation.
+ *
+ * @param func - The operation to be wrapped.
+ */
+export async function withSecretStorageKeyCache<T>(func: () => Promise<T>): Promise<T> {
+    secretStorageBeingAccessed = true;
+    try {
+        return await func();
+    } finally {
+        // Clear secret storage key cache now that work is complete
+        secretStorageBeingAccessed = false;
+        if (!isCachingAllowed()) {
+            secretStorageKeys = {};
+            secretStorageKeyInfo = {};
+        }
+    }
+}
+
 /**
  * This helper should be used whenever you need to access secret storage. It
  * ensures that secret storage (and also cross-signing since they each depend on
@@ -319,14 +341,13 @@ export async function promptForBackupPassphrase(): Promise<Uint8Array> {
  * @param {Function} [func] An operation to perform once secret storage has been
  * bootstrapped. Optional.
  * @param {bool} [forceReset] Reset secret storage even if it's already set up
- * @param {bool} [setupNewKeyBackup] Reset secret storage even if it's already set up
  */
-export async function accessSecretStorage(
-    func = async (): Promise<void> => {},
-    forceReset = false,
-    setupNewKeyBackup = true,
-): Promise<void> {
-    secretStorageBeingAccessed = true;
+export async function accessSecretStorage(func = async (): Promise<void> => {}, forceReset = false): Promise<void> {
+    await withSecretStorageKeyCache(() => doAccessSecretStorage(func, forceReset));
+}
+
+/** Helper for {@link #accessSecretStorage} */
+export async function doAccessSecretStorage(func = async (): Promise<void> => {}, forceReset = false): Promise<void> {
     try {
         const cli = MatrixClientPeg.safeGet();
         if (!(await cli.hasSecretStorageKey()) || forceReset) {
@@ -357,12 +378,7 @@ export async function accessSecretStorage(
                 throw new Error("Secret storage creation canceled");
             }
         } else {
-            const crypto = cli.getCrypto();
-            if (!crypto) {
-                throw new Error("End-to-end encryption is disabled - unable to access secret storage.");
-            }
-
-            await crypto.bootstrapCrossSigning({
+            await cli.bootstrapCrossSigning({
                 authUploadDeviceSigningKeys: async (makeRequest): Promise<void> => {
                     const { finished } = Modal.createDialog(InteractiveAuthDialog, {
                         title: _t("encryption|bootstrap_title"),
@@ -375,9 +391,8 @@ export async function accessSecretStorage(
                     }
                 },
             });
-            await crypto.bootstrapSecretStorage({
+            await cli.bootstrapSecretStorage({
                 getKeyBackupPassphrase: promptForBackupPassphrase,
-                setupNewKeyBackup,
             });
 
             const keyId = Object.keys(secretStorageKeys)[0];
@@ -403,13 +418,6 @@ export async function accessSecretStorage(
         logger.error(e);
         // Re-throw so that higher level logic can abort as needed
         throw e;
-    } finally {
-        // Clear secret storage key cache now that work is complete
-        secretStorageBeingAccessed = false;
-        if (!isCachingAllowed()) {
-            secretStorageKeys = {};
-            secretStorageKeyInfo = {};
-        }
     }
 }
 

src/SecurityManager.ts

@@ -17,6 +17,7 @@ limitations under the License.
 
 import React from "react";
 import { logger } from "matrix-js-sdk/src/logger";
+import { IKeyBackupInfo } from "matrix-js-sdk/src/crypto/keybackup";
 
 import { MatrixClientPeg } from "../../../../MatrixClientPeg";
 import { _t } from "../../../../languageHandler";
@@ -74,25 +75,24 @@ export default class CreateKeyBackupDialog extends React.PureComponent<IProps, I
         this.setState({
             error: undefined,
         });
+        let info: IKeyBackupInfo | undefined;
         const cli = MatrixClientPeg.safeGet();
         try {
-            // We don't want accessSecretStorage to create a backup for us - we
-            // will create one ourselves in the closure we pass in by calling
-            // resetKeyBackup.
-            const setupNewKeyBackup = false;
-            const forceReset = false;
-
-            await accessSecretStorage(
-                async (): Promise<void> => {
-                    const crypto = cli.getCrypto();
-                    if (!crypto) {
-                        throw new Error("End-to-end encryption is disabled - unable to create backup.");
-                    }
-                    await crypto.resetKeyBackup();
-                },
-                forceReset,
-                setupNewKeyBackup,
-            );
+            await accessSecretStorage(async (): Promise<void> => {
+                // `accessSecretStorage` will have bootstrapped secret storage if necessary, so we can now
+                // set up key backup.
+                //
+                // XXX: `bootstrapSecretStorage` also sets up key backup as a side effect, so there is a 90% chance
+                // this is actually redundant.
+                //
+                // The only time it would *not* be redundant would be if, for some reason, we had working 4S but no
+                // working key backup. (For example, if the user clicked "Delete Backup".)
+                info = await cli.prepareKeyBackupVersion(null /* random key */, {
+                    secureSecretStorage: true,
+                });
+                info = await cli.createKeyBackupVersion(info);
+            });
+            await cli.scheduleAllGroupSessionsForBackup();
             this.setState({
                 phase: Phase.Done,
             });
@@ -102,6 +102,9 @@ export default class CreateKeyBackupDialog extends React.PureComponent<IProps, I
             // delete the version, disable backup, or do nothing?  If we just
             // disable without deleting, we'll enable on next app reload since
             // it is trusted.
+            if (info?.version) {
+                cli.deleteKeyBackupVersion(info.version);
+            }
             this.setState({
                 error: true,
             });