fix(gateway): security hardening — auth guards, ownership checks, validation, rate limiting

apps/gateway/src/chat/chat.gateway.ts

@@ -11,18 +11,17 @@ import {
 } from '@nestjs/websockets';
 import { Server, Socket } from 'socket.io';
 import type { AgentSessionEvent } from '@mariozechner/pi-coding-agent';
+import type { Auth } from '@mosaic/auth';
 import { AgentService } from '../agent/agent.service.js';
+import { AUTH } from '../auth/auth.tokens.js';
 import { v4 as uuid } from 'uuid';
-
-interface ChatMessage {
-  conversationId?: string;
-  content: string;
-  provider?: string;
-  modelId?: string;
-}
+import { ChatSocketMessageDto } from './chat.dto.js';
+import { validateSocketSession } from './chat.gateway-auth.js';
 
 @WebSocketGateway({
-  cors: { origin: '*' },
+  cors: {
+    origin: process.env['GATEWAY_CORS_ORIGIN'] ?? 'http://localhost:3000',
+  },
   namespace: '/chat',
 })
 export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewayDisconnect {
@@ -35,13 +34,25 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
     { conversationId: string; cleanup: () => void }
   >();
 
-  constructor(@Inject(AgentService) private readonly agentService: AgentService) {}
+  constructor(
+    @Inject(AgentService) private readonly agentService: AgentService,
+    @Inject(AUTH) private readonly auth: Auth,
+  ) {}
 
   afterInit(): void {
     this.logger.log('Chat WebSocket gateway initialized');
   }
 
-  handleConnection(client: Socket): void {
+  async handleConnection(client: Socket): Promise<void> {
+    const session = await validateSocketSession(client.handshake.headers, this.auth);
+    if (!session) {
+      this.logger.warn(`Rejected unauthenticated WebSocket client: ${client.id}`);
+      client.disconnect();
+      return;
+    }
+
+    client.data.user = session.user;
+    client.data.session = session.session;
     this.logger.log(`Client connected: ${client.id}`);
   }
 
@@ -58,7 +69,7 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
   @SubscribeMessage('message')
   async handleMessage(
     @ConnectedSocket() client: Socket,
-    @MessageBody() data: ChatMessage,
+    @MessageBody() data: ChatSocketMessageDto,
   ): Promise<void> {
     const conversationId = data.conversationId ?? uuid();