feat: prompt injection defense & chat security hardening

packages/backend/package.json

@@ -18,6 +18,7 @@
     "@anthropic-ai/sdk": "^0.78.0",
     "@fastify/cors": "^11.0.0",
     "@fastify/multipart": "^9.4.0",
+    "@fastify/rate-limit": "^10.3.0",
     "@fastify/websocket": "^11.2.0",
     "@google/generative-ai": "^0.24.1",
     "@vitals/shared": "*",

packages/backend/src/app.ts

@@ -13,6 +13,7 @@ import { wsChatRoutes } from './routes/ws-chat.js';
 import { uploadRoutes } from './routes/upload.js';
 import { actionItemRoutes } from './routes/action-items.js';
 import multipart from '@fastify/multipart';
+import rateLimit from '@fastify/rate-limit';
 import websocket from '@fastify/websocket';
 import { databasePlugin } from './plugins/database.js';
 import { registerProviders } from './services/collectors/register.js';
@@ -30,6 +31,7 @@ export async function buildApp(env: EnvConfig) {
   });
 
   await app.register(multipart);
+  await app.register(rateLimit, { max: 60, timeWindow: '1 minute' });
   await app.register(websocket);
   await app.register(databasePlugin, { env });
 

packages/backend/src/db/migrations/009_unify_user_id.sql

@@ -0,0 +1,5 @@
+-- Unify user_id values: REST route previously used 'default' while WebSocket used the UUID.
+-- Migrate all 'default' conversations to the standard UUID so they remain accessible.
+UPDATE conversations
+SET user_id = '00000000-0000-0000-0000-000000000001'
+WHERE user_id = 'default';

packages/backend/src/db/queries/__tests__/conversations.test.ts

@@ -39,17 +39,28 @@ describe('conversation queries', () => {
 
   it('getConversation returns null when no rows returned', async () => {
     const pool = makePool([]);
-    const result = await getConversation(pool, 'uuid-nonexistent');
+    const result = await getConversation(pool, 'uuid-nonexistent', 'default');
     expect(result).toBeNull();
   });
 
   it('getConversation returns mapped row when found', async () => {
     const pool = makePool([fakeConvRow]);
-    const result = await getConversation(pool, 'uuid-1');
+    const result = await getConversation(pool, 'uuid-1', 'default');
     expect(result?.id).toBe('uuid-1');
     expect(result?.title).toBe('My chat');
   });
 
+  it('getConversation includes user_id in query', async () => {
+    const pool = makePool([fakeConvRow]);
+    await getConversation(pool, 'uuid-1', 'default');
+    const [sql, params] = (pool.query as ReturnType<typeof vi.fn>).mock.calls[0] as [
+      string,
+      unknown[],
+    ];
+    expect(sql).toMatch(/user_id/);
+    expect(params).toContain('default');
+  });
+
   it('createConversation inserts and returns mapped row', async () => {
     const pool = makePool([fakeConvRow]);
     const result = await createConversation(pool, 'default', 'My chat');
@@ -81,25 +92,44 @@ describe('conversation queries', () => {
 
   it('getMessages returns mapped array', async () => {
     const pool = makePool([fakeMsgRow]);
-    const result = await getMessages(pool, 'uuid-1');
+    const result = await getMessages(pool, 'uuid-1', 'default');
     expect(result[0].role).toBe('user');
     expect(result[0].content).toBe('Hello');
   });
 
-  it('deleteConversation calls DELETE', async () => {
+  it('getMessages includes user_id via join', async () => {
+    const pool = makePool([fakeMsgRow]);
+    await getMessages(pool, 'uuid-1', 'default');
+    const [sql, params] = (pool.query as ReturnType<typeof vi.fn>).mock.calls[0] as [
+      string,
+      unknown[],
+    ];
+    expect(sql).toMatch(/user_id/);
+    expect(params).toContain('default');
+  });
+
+  it('deleteConversation calls DELETE with user_id', async () => {
     const pool = makePool([]);
-    await deleteConversation(pool, 'uuid-1');
-    expect((pool.query as ReturnType<typeof vi.fn>).mock.calls[0][0]).toMatch(/DELETE/);
+    await deleteConversation(pool, 'uuid-1', 'default');
+    const [sql, params] = (pool.query as ReturnType<typeof vi.fn>).mock.calls[0] as [
+      string,
+      unknown[],
+    ];
+    expect(sql).toMatch(/DELETE/);
+    expect(sql).toMatch(/user_id/);
+    expect(params).toContain('default');
   });
 
-  it('updateConversationTitle calls UPDATE', async () => {
+  it('updateConversationTitle calls UPDATE with user_id', async () => {
     const pool = makePool([]);
-    await updateConversationTitle(pool, 'uuid-1', 'New title');
+    await updateConversationTitle(pool, 'uuid-1', 'New title', 'default');
     const [sql, params] = (pool.query as ReturnType<typeof vi.fn>).mock.calls[0] as [
       string,
       unknown[],
     ];
     expect(sql).toMatch(/UPDATE/);
+    expect(sql).toMatch(/user_id/);
     expect(params).toContain('New title');
+    expect(params).toContain('default');
   });
 });

packages/backend/src/db/queries/conversations.ts

@@ -56,8 +56,15 @@ export async function createConversation(
   return rowToConversation(rows[0] as Record<string, unknown>);
 }
 
-export async function getConversation(pool: pg.Pool, id: string): Promise<ConversationRow | null> {
-  const { rows } = await pool.query(`SELECT * FROM conversations WHERE id = $1`, [id]);
+export async function getConversation(
+  pool: pg.Pool,
+  id: string,
+  userId: string,
+): Promise<ConversationRow | null> {
+  const { rows } = await pool.query(`SELECT * FROM conversations WHERE id = $1 AND user_id = $2`, [
+    id,
+    userId,
+  ]);
   if (rows.length === 0) return null;
   return rowToConversation(rows[0] as Record<string, unknown>);
 }
@@ -74,15 +81,16 @@ export async function updateConversationTitle(
   pool: pg.Pool,
   id: string,
   title: string,
+  userId: string,
 ): Promise<void> {
-  await pool.query(`UPDATE conversations SET title = $1, updated_at = NOW() WHERE id = $2`, [
-    title,
-    id,
-  ]);
+  await pool.query(
+    `UPDATE conversations SET title = $1, updated_at = NOW() WHERE id = $2 AND user_id = $3`,
+    [title, id, userId],
+  );
 }
 
-export async function deleteConversation(pool: pg.Pool, id: string): Promise<void> {
-  await pool.query(`DELETE FROM conversations WHERE id = $1`, [id]);
+export async function deleteConversation(pool: pg.Pool, id: string, userId: string): Promise<void> {
+  await pool.query(`DELETE FROM conversations WHERE id = $1 AND user_id = $2`, [id, userId]);
 }
 
 export async function addMessage(
@@ -111,10 +119,17 @@ export async function addMessage(
   return rowToMessage(rows[0] as Record<string, unknown>);
 }
 
-export async function getMessages(pool: pg.Pool, conversationId: string): Promise<MessageRow[]> {
+export async function getMessages(
+  pool: pg.Pool,
+  conversationId: string,
+  userId: string,
+): Promise<MessageRow[]> {
   const { rows } = await pool.query(
-    `SELECT * FROM messages WHERE conversation_id = $1 ORDER BY created_at`,
-    [conversationId],
+    `SELECT m.* FROM messages m
+     JOIN conversations c ON m.conversation_id = c.id
+     WHERE m.conversation_id = $1 AND c.user_id = $2
+     ORDER BY m.created_at`,
+    [conversationId, userId],
   );
   return rows.map((r) => rowToMessage(r as Record<string, unknown>));
 }

packages/backend/src/routes/__tests__/chat.test.ts

@@ -15,14 +15,14 @@ vi.mock('../../services/collectors/register.js', () => ({
 // Mock conversation queries so tests don't hit the DB
 vi.mock('../../db/queries/conversations.js', () => ({
   createConversation: vi.fn().mockResolvedValue({
-    id: 'conv-1',
+    id: '00000000-0000-0000-0000-000000000001',
     title: null,
     userId: 'default',
     createdAt: new Date(),
     updatedAt: new Date(),
   }),
   getConversation: vi.fn().mockResolvedValue({
-    id: 'conv-1',
+    id: '00000000-0000-0000-0000-000000000001',
     title: null,
     userId: 'default',
     createdAt: new Date(),
@@ -98,6 +98,17 @@ describe('POST /api/chat', () => {
     await app.close();
   });
 
+  it('returns 400 when conversationId is not a valid UUID', async () => {
+    const app = await buildApp(testEnv);
+    const response = await app.inject({
+      method: 'POST',
+      url: '/api/chat',
+      payload: { message: 'Hello', conversationId: 'not-a-uuid' },
+    });
+    expect(response.statusCode).toBe(400);
+    await app.close();
+  });
+
   it('returns 404 when conversationId does not exist', async () => {
     const { getConversation } = await import('../../db/queries/conversations.js');
     (getConversation as ReturnType<typeof vi.fn>).mockResolvedValueOnce(null);
@@ -106,7 +117,10 @@ describe('POST /api/chat', () => {
     const response = await app.inject({
       method: 'POST',
       url: '/api/chat',
-      payload: { message: 'Hello', conversationId: 'nonexistent' },
+      payload: {
+        message: 'Hello',
+        conversationId: '00000000-0000-0000-0000-000000000099',
+      },
     });
     expect(response.statusCode).toBe(404);
     await app.close();
@@ -121,7 +135,7 @@ describe('POST /api/chat', () => {
     });
     expect(response.statusCode).toBe(200);
     const body = response.json<{ conversationId: string; response: string }>();
-    expect(body.conversationId).toBe('conv-1');
+    expect(body.conversationId).toBe('00000000-0000-0000-0000-000000000001');
     expect(body.response).toContain('150g');
     await app.close();
   });
@@ -142,14 +156,24 @@ describe('GET /api/chat/conversations', () => {
 });
 
 describe('GET /api/chat/conversations/:id', () => {
+  it('returns 400 for invalid UUID', async () => {
+    const app = await buildApp(testEnv);
+    const response = await app.inject({
+      method: 'GET',
+      url: '/api/chat/conversations/not-a-uuid',
+    });
+    expect(response.statusCode).toBe(400);
+    await app.close();
+  });
+
   it('returns 404 when conversation does not exist', async () => {
     const { getConversation } = await import('../../db/queries/conversations.js');
     (getConversation as ReturnType<typeof vi.fn>).mockResolvedValueOnce(null);
 
     const app = await buildApp(testEnv);
     const response = await app.inject({
       method: 'GET',
-      url: '/api/chat/conversations/nonexistent',
+      url: '/api/chat/conversations/00000000-0000-0000-0000-000000000099',
     });
     expect(response.statusCode).toBe(404);
     await app.close();
@@ -159,7 +183,7 @@ describe('GET /api/chat/conversations/:id', () => {
     const app = await buildApp(testEnv);
     const response = await app.inject({
       method: 'GET',
-      url: '/api/chat/conversations/conv-1',
+      url: '/api/chat/conversations/00000000-0000-0000-0000-000000000001',
     });
     expect(response.statusCode).toBe(200);
     const body = response.json<{ conversation: unknown; messages: unknown[] }>();
@@ -170,14 +194,24 @@ describe('GET /api/chat/conversations/:id', () => {
 });
 
 describe('DELETE /api/chat/conversations/:id', () => {
+  it('returns 400 for invalid UUID', async () => {
+    const app = await buildApp(testEnv);
+    const response = await app.inject({
+      method: 'DELETE',
+      url: '/api/chat/conversations/not-a-uuid',
+    });
+    expect(response.statusCode).toBe(400);
+    await app.close();
+  });
+
   it('returns 404 when conversation does not exist', async () => {
     const { getConversation } = await import('../../db/queries/conversations.js');
     (getConversation as ReturnType<typeof vi.fn>).mockResolvedValueOnce(null);
 
     const app = await buildApp(testEnv);
     const response = await app.inject({
       method: 'DELETE',
-      url: '/api/chat/conversations/nonexistent',
+      url: '/api/chat/conversations/00000000-0000-0000-0000-000000000099',
     });
     expect(response.statusCode).toBe(404);
     await app.close();
@@ -187,7 +221,7 @@ describe('DELETE /api/chat/conversations/:id', () => {
     const app = await buildApp(testEnv);
     const response = await app.inject({
       method: 'DELETE',
-      url: '/api/chat/conversations/conv-1',
+      url: '/api/chat/conversations/00000000-0000-0000-0000-000000000001',
     });
     expect(response.statusCode).toBe(204);
     await app.close();