CDSI Support

ts/textsecure/cds/CDSISocket.ts

@@ -0,0 +1,100 @@
+// Copyright 2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { Cds2Client } from '@signalapp/libsignal-client';
+
+import { strictAssert } from '../../util/assert';
+import { DAY } from '../../util/durations';
+import { SignalService as Proto } from '../../protobuf';
+import { CDSSocketBase, CDSSocketState } from './CDSSocketBase';
+import type { CDSSocketBaseOptionsType } from './CDSSocketBase';
+
+export type CDSISocketOptionsType = Readonly<{
+  mrenclave: Buffer;
+  trustedCaCert: Buffer;
+}> &
+  CDSSocketBaseOptionsType;
+
+export class CDSISocket extends CDSSocketBase<CDSISocketOptionsType> {
+  private privCdsClient: Cds2Client | undefined;
+
+  public override async handshake(): Promise<void> {
+    strictAssert(
+      this.state === CDSSocketState.Open,
+      'CDSI handshake called twice'
+    );
+    this.state = CDSSocketState.Handshake;
+
+    {
+      const { done, value: attestationMessage } =
+        await this.socketIterator.next();
+      strictAssert(!done, 'CDSI socket closed before handshake');
+
+      const earliestValidTimestamp = new Date(Date.now() - DAY);
+
+      strictAssert(
+        this.privCdsClient === undefined,
+        'CDSI handshake called twice'
+      );
+      this.privCdsClient = Cds2Client.new_NOT_FOR_PRODUCTION(
+        this.options.mrenclave,
+        this.options.trustedCaCert,
+        attestationMessage,
+        earliestValidTimestamp
+      );
+    }
+
+    this.socket.sendBytes(this.cdsClient.initialRequest());
+
+    {
+      const { done, value: message } = await this.socketIterator.next();
+      strictAssert(!done, 'CDSI socket expected handshake data');
+
+      this.cdsClient.completeHandshake(message);
+    }
+
+    this.state = CDSSocketState.Established;
+  }
+
+  protected override async sendRequest(
+    _version: number,
+    request: Buffer
+  ): Promise<void> {
+    this.socket.sendBytes(this.cdsClient.establishedSend(request));
+
+    const { done, value: ciphertext } = await this.socketIterator.next();
+    strictAssert(!done, 'CDSISocket.sendRequest(): expected token message');
+
+    const message = await this.decryptResponse(ciphertext);
+
+    this.logger.info('CDSISocket.sendRequest(): processing token message');
+
+    const { token } = Proto.CDSClientResponse.decode(message);
+    strictAssert(token, 'CDSISocket.sendRequest(): expected token');
+
+    this.socket.sendBytes(
+      this.cdsClient.establishedSend(
+        Buffer.from(
+          Proto.CDSClientRequest.encode({
+            tokenAck: true,
+          }).finish()
+        )
+      )
+    );
+  }
+
+  protected override async decryptResponse(
+    ciphertext: Buffer
+  ): Promise<Buffer> {
+    return this.cdsClient.establishedRecv(ciphertext);
+  }
+
+  //
+  // Private
+  //
+
+  private get cdsClient(): Cds2Client {
+    strictAssert(this.privCdsClient, 'CDSISocket did not start handshake');
+    return this.privCdsClient;
+  }
+}