Element-R: implement {get,set}TrustCrossSignedDevices

A precursor to element-hq/element-web#25092

src/client.ts

@@ -2748,24 +2748,28 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
      * Default: true
      *
      * @returns True if trusting cross-signed devices
+     *
+     * @deprecated Prefer {@link CryptoApi.getTrustCrossSignedDevices | `CryptoApi.getTrustCrossSignedDevices`}.
      */
     public getCryptoTrustCrossSignedDevices(): boolean {
-        if (!this.crypto) {
+        if (!this.cryptoBackend) {
             throw new Error("End-to-end encryption disabled");
         }
-        return this.crypto.getCryptoTrustCrossSignedDevices();
+        return this.cryptoBackend.getTrustCrossSignedDevices();
     }
 
     /**
      * See getCryptoTrustCrossSignedDevices
      *
      * @param val - True to trust cross-signed devices
+     *
+     * @deprecated Prefer {@link CryptoApi.setTrustCrossSignedDevices | `CryptoApi.setTrustCrossSignedDevices`}.
      */
     public setCryptoTrustCrossSignedDevices(val: boolean): void {
-        if (!this.crypto) {
+        if (!this.cryptoBackend) {
             throw new Error("End-to-end encryption disabled");
         }
-        this.crypto.setCryptoTrustCrossSignedDevices(val);
+        this.cryptoBackend.setTrustCrossSignedDevices(val);
     }
 
     /**

src/crypto-api.ts

@@ -72,4 +72,25 @@ export interface CryptoApi {
      *    session export objects
      */
     exportRoomKeys(): Promise<IMegolmSessionData[]>;
+
+    /**
+     * Set whether to trust other user's signatures of their devices.
+     *
+     * If false, devices will only be considered 'verified' if we have
+     * verified that device individually (effectively disabling cross-signing).
+     *
+     * `true` by default.
+     *
+     * @param val - the new value
+     */
+    setTrustCrossSignedDevices(val: boolean): void;
+
+    /**
+     * Return whether we trust other user's signatures of their devices.
+     *
+     * @see {@link CryptoApi#setTrustCrossSignedDevices}
+     *
+     * @return `true` if we trust cross-signed devices, otherwise `false`.
+     */
+    getTrustCrossSignedDevices(): boolean;
 }

src/crypto/index.ts

@@ -605,18 +605,23 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
      *
      * @returns True if trusting cross-signed devices
      */
+    public getTrustCrossSignedDevices(): boolean {
+        return this.trustCrossSignedDevices;
+    }
+
+    /**
+     * @deprecated Use {@link CryptoApi#getTrustCrossSignedDevices}.
+     */
     public getCryptoTrustCrossSignedDevices(): boolean {
         return this.trustCrossSignedDevices;
     }
 
     /**
      * See getCryptoTrustCrossSignedDevices
-
-     * This may be set before initCrypto() is called to ensure no races occur.
      *
      * @param val - True to trust cross-signed devices
      */
-    public setCryptoTrustCrossSignedDevices(val: boolean): void {
+    public setTrustCrossSignedDevices(val: boolean): void {
         this.trustCrossSignedDevices = val;
 
         for (const userId of this.deviceList.getKnownUserIds()) {
@@ -634,6 +639,13 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
         }
     }
 
+    /**
+     * @deprecated Use {@link CryptoApi#setTrustCrossSignedDevices}.
+     */
+    public setCryptoTrustCrossSignedDevices(val: boolean): void {
+        this.setTrustCrossSignedDevices(val);
+    }
+
     /**
      * Create a recovery key from a user-supplied passphrase.
      *

src/rust-crypto/rust-crypto.ts

@@ -36,6 +36,7 @@ import { MapWithDefault } from "../utils";
  */
 export class RustCrypto implements CryptoBackend {
     public globalErrorOnUnknownDevices = false;
+    private _trustCrossSignedDevices = true;
 
     /** whether {@link stop} has been called */
     private stopped = false;
@@ -165,6 +166,22 @@ export class RustCrypto implements CryptoBackend {
         return [];
     }
 
+    /**
+     * Implementation of {@link CryptoApi#getTrustCrossSignedDevices}.
+     */
+    public getTrustCrossSignedDevices(): boolean {
+        return this._trustCrossSignedDevices;
+    }
+
+    /**
+     * Implementation of {@link CryptoApi#setTrustCrossSignedDevices}.
+     */
+    public setTrustCrossSignedDevices(val: boolean): void {
+        this._trustCrossSignedDevices = val;
+        // TODO: legacy crypto goes through the list of known devices and emits DeviceVerificationChanged
+        //  events. Maybe we need to do the same?
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // SyncCryptoCallbacks implementation