Add CryptoApi#resetEncryption

matrix-org · Jan 14, 2025 · f99e069 · f99e069
1 parent f22d5e9
commit f99e069
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Showing 5 changed files with 59 additions and 7 deletions.
diff --git a/src/@types/event.ts b/src/@types/event.ts
@@ -373,7 +373,7 @@ export interface AccountDataEvents extends SecretStorageAccountDataEvents {
     [EventType.PushRules]: IPushRules;
     [EventType.Direct]: { [userId: string]: string[] };
     [EventType.IgnoredUserList]: { [userId: string]: {} };
-    "m.secret_storage.default_key": { key: string };
+    "m.secret_storage.default_key": { key: string } | {};
     "m.identity_server": { base_url: string | null };
     [key: `${typeof LOCAL_NOTIFICATION_SETTINGS_PREFIX.name}.${string}`]: LocalNotificationSettings;
     [key: `m.secret_storage.key.${string}`]: SecretStorageKeyDescription;

diff --git a/src/crypto-api/index.ts b/src/crypto-api/index.ts
@@ -396,6 +396,19 @@ export interface CryptoApi {
         payload: ToDevicePayload,
     ): Promise<ToDeviceBatch>;
 
+    /**
+     *
+     * - Disable backing up room keys and delete any existing backup.
+     * - Remove the default secret storage key from the account data (ie: the recovery key).
+     * - Reset the cross-signing keys.
+     * - Re-enable backing up room keys if enabled before.
+     *
+     * @param authUploadDeviceSigningKeys - Callback to authenticate the upload of device signing keys.
+     *                                      Used when resetting the cross signing keys.
+     *                                      See {@link BootstrapCrossSigningOpts#authUploadDeviceSigningKeys}.
+     */
+    resetEncryption(authUploadDeviceSigningKeys: UIAuthCallback<void>): Promise<void>;
+
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // Device/User verification

diff --git a/src/crypto/index.ts b/src/crypto/index.ts
@@ -4340,6 +4340,13 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     ): Promise<KeyBackupRestoreResult> {
         throw new Error("Not implemented");
     }
+
+    /**
+     * Stub function -- resetEncryption is not implemented here, so throw error
+     */
+    public resetEncryption(): Promise<void> {
+        throw new Error("Not implemented");
+    }
 }
 
 /**

diff --git a/src/rust-crypto/rust-crypto.ts b/src/rust-crypto/rust-crypto.ts
@@ -88,6 +88,7 @@ import { PerSessionKeyBackupDownloader } from "./PerSessionKeyBackupDownloader.t
 import { DehydratedDeviceManager } from "./DehydratedDeviceManager.ts";
 import { VerificationMethod } from "../types.ts";
 import { keyFromAuthData } from "../common-crypto/key-passphrase.ts";
+import { UIAuthCallback } from "../interactive-auth.ts";
 
 const ALL_VERIFICATION_METHODS = [
     VerificationMethod.Sas,
@@ -1472,6 +1473,28 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, CryptoEventH
         return batch;
     }
 
+    /**
+     * Implementation of {@link CryptoApi#resetEncryption}.
+     */
+    public async resetEncryption(authUploadDeviceSigningKeys: UIAuthCallback<void>): Promise<void> {
+        const backupEnabled = (await this.backupManager.getActiveBackupVersion()) !== null;
+
+        // Delete all the backup
+        await this.backupManager.deleteAllKeyBackupVersions();
+
+        // Disable the recovery key and the secret storage
+        await this.secretStorage.setDefaultKeyId(null);
+
+        // Reset the cross-signing keys
+        await this.crossSigningIdentity.bootstrapCrossSigning({
+            setupNewCrossSigning: true,
+            authUploadDeviceSigningKeys,
+        });
+
+        // Enable the key backup if it was enabled before
+        if (backupEnabled) await this.backupManager.checkKeyBackupAndEnable(true);
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // SyncCryptoCallbacks implementation

diff --git a/src/secret-storage.ts b/src/secret-storage.ts
@@ -315,10 +315,12 @@ export interface ServerSideSecretStorage {
 
     /**
      * Set the default key ID for encrypting secrets.
+     * If keyId is `null`, the default key id value in the account data will be set to an empty object.
+     * This is considered as "disabling" the default key.
      *
      * @param keyId - The new default key ID
      */
-    setDefaultKeyId(keyId: string): Promise<void>;
+    setDefaultKeyId(keyId: string | null): Promise<void>;
 }
 
 /**
@@ -352,26 +354,33 @@ export class ServerSideSecretStorageImpl implements ServerSideSecretStorage {
      */
     public async getDefaultKeyId(): Promise<string | null> {
         const defaultKey = await this.accountDataAdapter.getAccountDataFromServer("m.secret_storage.default_key");
-        if (!defaultKey) return null;
-        return defaultKey.key ?? null;
+        if (!defaultKey || !Object.keys(defaultKey).length) return null;
+        return (defaultKey as { key: string }).key ?? null;
     }
 
     /**
      * Set the default key ID for encrypting secrets.
      *
      * @param keyId - The new default key ID
      */
-    public setDefaultKeyId(keyId: string): Promise<void> {
+    public setDefaultKeyId(keyId: string | null): Promise<void> {
         return new Promise<void>((resolve, reject) => {
             const listener = (ev: MatrixEvent): void => {
-                if (ev.getType() === "m.secret_storage.default_key" && ev.getContent().key === keyId) {
+                const content = ev.getContent();
+                const isSameKey = keyId === null ? !Object.keys(content).length : content.key === keyId;
+                if (ev.getType() === "m.secret_storage.default_key" && isSameKey) {
                     this.accountDataAdapter.removeListener(ClientEvent.AccountData, listener);
                     resolve();
                 }
             };
             this.accountDataAdapter.on(ClientEvent.AccountData, listener);
 
-            this.accountDataAdapter.setAccountData("m.secret_storage.default_key", { key: keyId }).catch((e) => {
+            // The spec says that the key should be an object with a `key` property
+            // https://spec.matrix.org/v1.13/client-server-api/#key-storage
+            // To delete the default key, we send an empty object like the rust sdk does
+            // (see https://docs.rs/matrix-sdk/latest/matrix_sdk/encryption/recovery/struct.Recovery.html#method.reset_identity)
+            const newValue = keyId === null ? {} : { key: keyId };
+            this.accountDataAdapter.setAccountData("m.secret_storage.default_key", newValue).catch((e) => {
                 this.accountDataAdapter.removeListener(ClientEvent.AccountData, listener);
                 reject(e);
             });