fix(cloud-agent): rate limit stream tickets by IP

apps/web/src/app/api/cloud-agent-next/sessions/stream-ticket/route.test.ts

@@ -0,0 +1,56 @@
+import { checkRateLimit } from '@vercel/firewall';
+import { getUserFromAuth } from '@/lib/user/server';
+
+jest.mock('@vercel/firewall');
+jest.mock('@/lib/user/server');
+jest.mock('@/lib/drizzle');
+jest.mock('@/lib/cloud-agent/session-ownership');
+jest.mock('@/lib/cloud-agent/stream-ticket');
+jest.mock('@sentry/nextjs');
+
+import { POST } from './route';
+
+const mockCheckRateLimit = jest.mocked(checkRateLimit);
+const mockGetUserFromAuth = jest.mocked(getUserFromAuth);
+
+function createRequest(): Request {
+  return new Request('http://localhost:3000/api/cloud-agent-next/sessions/stream-ticket', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ cloudAgentSessionId: 'session-1' }),
+  });
+}
+
+describe('POST /api/cloud-agent-next/sessions/stream-ticket', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    mockCheckRateLimit.mockResolvedValue({ rateLimited: false });
+  });
+
+  test('returns 429 before authentication when the client IP is rate limited', async () => {
+    mockCheckRateLimit.mockResolvedValue({ rateLimited: true });
+    const request = createRequest();
+
+    const response = await POST(request);
+
+    expect(response.status).toBe(429);
+    expect(response.headers.get('Retry-After')).toBe('60');
+    await expect(response.json()).resolves.toEqual({
+      error: 'Rate limit exceeded. Please try again later.',
+    });
+    expect(mockCheckRateLimit).toHaveBeenCalledWith('stream-ticket-ip', { request });
+    expect(mockGetUserFromAuth).not.toHaveBeenCalled();
+  });
+
+  test('continues to authentication when the client IP is allowed', async () => {
+    const authFailedResponse = Response.json({ error: 'Unauthorized' }, { status: 401 });
+    mockGetUserFromAuth.mockResolvedValue({ user: null, authFailedResponse } as never);
+    const request = createRequest();
+
+    const response = await POST(request);
+
+    expect(mockCheckRateLimit).toHaveBeenCalledWith('stream-ticket-ip', { request });
+    expect(mockGetUserFromAuth).toHaveBeenCalledWith({ adminOnly: false });
+    expect(response).toBe(authFailedResponse);
+  });
+});

apps/web/src/app/api/cloud-agent-next/sessions/stream-ticket/route.ts

@@ -8,8 +8,11 @@ import {
 import { signStreamTicket } from '@/lib/cloud-agent/stream-ticket';
 import { TRPCError } from '@trpc/server';
 import { captureException } from '@sentry/nextjs';
+import { checkRateLimit } from '@vercel/firewall';
 import * as z from 'zod';
 
+const STREAM_TICKET_IP_RATE_LIMIT_ID = 'stream-ticket-ip';
+
 const streamTicketSchema = z.object({
   cloudAgentSessionId: z.string().min(1),
   organizationId: z.string().uuid().optional(),
@@ -51,6 +54,14 @@ function handleTRPCError(error: unknown): NextResponse {
  */
 export async function POST(request: Request) {
   try {
+    const { rateLimited } = await checkRateLimit(STREAM_TICKET_IP_RATE_LIMIT_ID, { request });
+    if (rateLimited) {
+      return NextResponse.json(
+        { error: 'Rate limit exceeded. Please try again later.' },
+        { status: 429, headers: { 'Retry-After': '60' } }
+      );
+    }
+
     const { user, authFailedResponse } = await getUserFromAuth({ adminOnly: false });
 
     if (authFailedResponse) {