fix(gateway): enforce request body size limits

src/automation/webhooks.test.ts

@@ -220,6 +220,24 @@ describe('WebhookHandler', () => {
     expect(messages).toHaveLength(0);
   });
 
+  it('rejects oversized payloads with 413', async () => {
+    const webhooks = [makeWebhook()];
+    handler = new WebhookHandler(webhooks, mockChannelRegistry as any, 'shared_session', 16);
+
+    const messages: InboundMessage[] = [];
+    handler.onMessage((msg: InboundMessage) => messages.push(msg));
+    await handler.connect();
+
+    const req = mockRequest('x'.repeat(64));
+    const res = mockResponse();
+
+    const result = await handler.handleRequest('test-hook', req, res);
+
+    expect(result).toBe(false);
+    expect(res.statusCode_).toBe(413);
+    expect(messages).toHaveLength(0);
+  });
+
   it('forwards response to output channel on send()', async () => {
     const mockOutputAdapter = {
       send: vi.fn().mockResolvedValue(undefined),

src/automation/webhooks.ts

@@ -3,6 +3,7 @@ import type { IncomingMessage, ServerResponse } from 'http';
 import type { WebhookConfig } from '../config/schema.js';
 import type { ChannelAdapter, ChannelStatus, InboundMessage, OutboundMessage } from '../channels/types.js';
 import { auditLogger } from '../audit/index.js';
+import { RequestBodyTooLargeError, readRequestBody } from '../utils/httpBody.js';
 
 /** Minimal interface for the parts of ChannelRegistry we need. */
 interface ChannelLookup {
@@ -11,16 +12,6 @@ interface ChannelLookup {
 
 type DeliveryMode = 'shared_session' | 'isolated_job';
 
-/** Read the full request body as a string. */
-function readBody(req: IncomingMessage): Promise<string> {
-  return new Promise((resolve, reject) => {
-    const chunks: Buffer[] = [];
-    req.on('data', (chunk: Buffer) => chunks.push(chunk));
-    req.on('end', () => resolve(Buffer.concat(chunks).toString('utf-8')));
-    req.on('error', reject);
-  });
-}
-
 /** Verify HMAC-SHA256 signature from the X-Webhook-Signature header. */
 function verifyHmac(body: string, secret: string, signature: string): boolean {
   const expected = createHmac('sha256', secret).update(body).digest('hex');
@@ -62,6 +53,7 @@ function renderTemplate(template: string, body: string): string {
 }
 
 export class WebhookHandler implements ChannelAdapter {
+  private static readonly DEFAULT_MAX_REQUEST_BODY_BYTES = 1_048_576; // 1 MiB
   readonly name = 'webhook';
   private _status: ChannelStatus = 'disconnected';
   private messageHandler?: (msg: InboundMessage) => void;
@@ -71,6 +63,7 @@ export class WebhookHandler implements ChannelAdapter {
     private readonly webhookConfigs: WebhookConfig[],
     private readonly channelLookup: ChannelLookup,
     private readonly deliveryMode: DeliveryMode = 'shared_session',
+    private readonly maxRequestBodyBytes: number = WebhookHandler.DEFAULT_MAX_REQUEST_BODY_BYTES,
   ) {
     for (const webhook of webhookConfigs) {
       this.webhooks.set(webhook.name, webhook);
@@ -137,7 +130,21 @@ export class WebhookHandler implements ChannelAdapter {
       return false;
     }
 
-    const body = await readBody(req);
+    let body = '';
+    try {
+      body = await readRequestBody(req, { maxBytes: this.maxRequestBodyBytes });
+    } catch (err) {
+      if (err instanceof RequestBodyTooLargeError) {
+        auditLogger?.webhookDenied(webhookName, `Payload too large (>${this.maxRequestBodyBytes} bytes)`);
+        res.writeHead(413, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ error: 'Payload too large' }));
+        return false;
+      }
+      auditLogger?.webhookDenied(webhookName, err instanceof Error ? err.message : 'Failed to read request body');
+      res.writeHead(400, { 'Content-Type': 'application/json' });
+      res.end(JSON.stringify({ error: 'Invalid request body' }));
+      return false;
+    }
 
     // Verify HMAC if secret is configured
     const signatureVerified = !webhook.secret;
@@ -195,4 +202,4 @@ export class WebhookHandler implements ChannelAdapter {
 }
 
 // Export helpers for testing
-export { readBody as _readBody, verifyHmac as _verifyHmac, renderTemplate as _renderTemplate };
+export { verifyHmac as _verifyHmac, renderTemplate as _renderTemplate };

src/config/schema.test.ts

@@ -28,6 +28,26 @@ describe('configSchema — sandbox', () => {
   });
 });
 
+describe('configSchema — server', () => {
+  const minimalConfig = {
+    telegram: { bot_token: 'test', allowed_chat_ids: [1] },
+    models: { default: { provider: 'anthropic', model: 'claude-3' } },
+  };
+
+  it('defaults max_request_body_bytes', () => {
+    const result = configSchema.parse(minimalConfig);
+    expect(result.server.max_request_body_bytes).toBe(1_048_576);
+  });
+
+  it('accepts custom max_request_body_bytes', () => {
+    const result = configSchema.parse({
+      ...minimalConfig,
+      server: { max_request_body_bytes: 2048 },
+    });
+    expect(result.server.max_request_body_bytes).toBe(2048);
+  });
+});
+
 describe('configSchema — agent_configs', () => {
   const minimalConfig = {
     telegram: { bot_token: 'test', allowed_chat_ids: [1] },

src/config/schema.ts

@@ -36,6 +36,8 @@ const serverSchema = z.object({
   auth_http: z.boolean().default(true),
   /** Single-client gateway lock. When true, only one WebSocket client can be connected at a time. */
   lock: z.boolean().default(false),
+  /** Maximum size (bytes) for inbound HTTP request bodies (webhooks/Gmail push). */
+  max_request_body_bytes: z.number().min(1024).max(10 * 1024 * 1024).default(1_048_576),
 });
 
 /** All supported model provider identifiers. Used by the config schema and TUI autocompletion. */

src/daemon/channels.ts

@@ -99,7 +99,12 @@ export function registerChannels(deps: ChannelsDeps): ChannelsResult {
   // Register webhook handler adapter (if any webhooks configured)
   let webhookHandler: WebhookHandler | undefined;
   if (config.automation.webhooks.length > 0) {
-    webhookHandler = new WebhookHandler(config.automation.webhooks, channelRegistry, config.automation.delivery_mode);
+    webhookHandler = new WebhookHandler(
+      config.automation.webhooks,
+      channelRegistry,
+      config.automation.delivery_mode,
+      config.server.max_request_body_bytes,
+    );
     channelRegistry.register(webhookHandler);
     gateway.setWebhookHandler(webhookHandler);
     console.log(`Registered ${config.automation.webhooks.length} webhook(s)`);

src/daemon/services.ts

@@ -311,6 +311,7 @@ export function createGateway(deps: GatewayDeps): GatewayServer {
     },
     authHttp: config.server.auth_http,
     lock: config.server.lock,
+    maxRequestBodyBytes: config.server.max_request_body_bytes,
     commandRegistry: deps.commandRegistry,
     intentRegistry: deps.intentRegistry,
     routingPolicy: deps.routingPolicy,

src/gateway/server.test.ts

@@ -438,3 +438,68 @@ describe('GatewayServer HTTP auth', () => {
     expect(res.headers.get('content-type')).toBe('text/html');
   });
 });
+
+describe('GatewayServer request body limits', () => {
+  const BODY_PORT = 18896;
+  let bodyLimitServer: GatewayServer;
+  const gmailHandler = {
+    handlePushNotification: vi.fn(async () => {}),
+  };
+
+  beforeAll(async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+    bodyLimitServer = new GatewayServer({
+      port: BODY_PORT,
+      sessionManager: mockSessionManager as unknown as GatewayServerConfig['sessionManager'],
+      modelClient: mockModelClient,
+      systemPrompt: 'Test prompt',
+      toolRegistry: mockToolRegistry as unknown as GatewayServerConfig['toolRegistry'],
+      toolExecutor: mockToolExecutor as unknown as GatewayServerConfig['toolExecutor'],
+      gmailHandler: gmailHandler as unknown as GatewayServerConfig['gmailHandler'],
+      maxRequestBodyBytes: 64,
+      uiDir: resolve(import.meta.dirname, 'ui'),
+    });
+    await bodyLimitServer.start();
+  });
+
+  afterAll(async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+    await bodyLimitServer.stop();
+  });
+
+  it('accepts gmail push body under limit', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+    gmailHandler.handlePushNotification.mockClear();
+
+    const body = JSON.stringify({ message: { data: 'abc' } });
+    const res = await fetch(`http://127.0.0.1:${BODY_PORT}/gmail/push`, {
+      method: 'POST',
+      body,
+      headers: { 'Content-Type': 'application/json' },
+    });
+    expect(res.status).toBe(200);
+    expect(gmailHandler.handlePushNotification).toHaveBeenCalledWith('abc');
+  });
+
+  it('rejects gmail push body over limit with 413', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+    gmailHandler.handlePushNotification.mockClear();
+
+    const body = JSON.stringify({ message: { data: 'x'.repeat(2048) } });
+    const res = await fetch(`http://127.0.0.1:${BODY_PORT}/gmail/push`, {
+      method: 'POST',
+      body,
+      headers: { 'Content-Type': 'application/json' },
+    });
+    expect(res.status).toBe(413);
+    expect(gmailHandler.handlePushNotification).not.toHaveBeenCalled();
+  });
+});

src/gateway/server.ts

@@ -41,6 +41,7 @@ import type { CommandRegistry } from '../commands/index.js';
 import type { ComponentRegistry } from '../intents/index.js';
 import type { RoutingPolicy } from '../routing/index.js';
 import type { ChannelRegistry } from '../channels/index.js';
+import { RequestBodyTooLargeError, readRequestBody } from '../utils/httpBody.js';
 
 export interface GatewayServerConfig {
   port: number;
@@ -67,6 +68,8 @@ export interface GatewayServerConfig {
   gmailHandler?: GmailWatcher;
   /** Optional callback to retrieve per-session token usage data for the dashboard. */
   getTokenUsage?: () => TokenUsageEntry[];
+  /** Maximum allowed request body size for inbound HTTP POST bodies. */
+  maxRequestBodyBytes?: number;
   /** Optional pairing manager for DM pairing code management via gateway. */
   pairingManager?: PairingManager;
   memoryStore?: MemoryStore;
@@ -76,6 +79,7 @@ export interface GatewayServerConfig {
 }
 
 export class GatewayServer {
+  private static readonly DEFAULT_MAX_REQUEST_BODY_BYTES = 1_048_576; // 1 MiB
   private wss: WebSocketServer | null = null;
   private httpServer: HttpServer | null = null;
   private router: Router;
@@ -348,9 +352,14 @@ export class GatewayServer {
         res.writeHead(200, { 'Content-Type': 'application/json' });
         res.end(JSON.stringify({ ok: true }));
       } catch (err) {
-        console.error('Gmail push handler error:', err instanceof Error ? err.message : err);
-        res.writeHead(400, { 'Content-Type': 'application/json' });
-        res.end(JSON.stringify({ error: 'Invalid request' }));
+        if (err instanceof RequestBodyTooLargeError) {
+          res.writeHead(413, { 'Content-Type': 'application/json' });
+          res.end(JSON.stringify({ error: 'Payload too large' }));
+        } else {
+          console.error('Gmail push handler error:', err instanceof Error ? err.message : err);
+          res.writeHead(400, { 'Content-Type': 'application/json' });
+          res.end(JSON.stringify({ error: 'Invalid request' }));
+        }
       }
       return;
     }
@@ -444,11 +453,7 @@ export class GatewayServer {
 
   /** Read the full request body as a string. */
   private readRequestBody(req: IncomingMessage): Promise<string> {
-    return new Promise((resolve, reject) => {
-      const chunks: Buffer[] = [];
-      req.on('data', (chunk: Buffer) => chunks.push(chunk));
-      req.on('end', () => resolve(Buffer.concat(chunks).toString('utf-8')));
-      req.on('error', reject);
-    });
+    const maxBytes = this.config.maxRequestBodyBytes ?? GatewayServer.DEFAULT_MAX_REQUEST_BODY_BYTES;
+    return readRequestBody(req, { maxBytes });
   }
 }

src/utils/httpBody.test.ts

@@ -0,0 +1,42 @@
+import { describe, it, expect } from 'vitest';
+import { EventEmitter } from 'events';
+import type { IncomingMessage } from 'http';
+import { readRequestBody, RequestBodyTooLargeError } from './httpBody.js';
+
+class MockRequest extends EventEmitter {
+  destroyed = false;
+
+  destroy(): this {
+    this.destroyed = true;
+    return this;
+  }
+}
+
+function asIncoming(req: MockRequest): IncomingMessage {
+  return req as unknown as IncomingMessage;
+}
+
+describe('readRequestBody', () => {
+  it('reads body under size limit', async () => {
+    const req = new MockRequest();
+    const bodyPromise = readRequestBody(asIncoming(req), { maxBytes: 1024 });
+
+    req.emit('data', Buffer.from('hello'));
+    req.emit('data', Buffer.from(' world'));
+    req.emit('end');
+
+    await expect(bodyPromise).resolves.toBe('hello world');
+    expect(req.destroyed).toBe(false);
+  });
+
+  it('rejects oversized body and destroys request', async () => {
+    const req = new MockRequest();
+    const bodyPromise = readRequestBody(asIncoming(req), { maxBytes: 5 });
+
+    req.emit('data', Buffer.from('12345'));
+    req.emit('data', Buffer.from('6'));
+
+    await expect(bodyPromise).rejects.toBeInstanceOf(RequestBodyTooLargeError);
+    expect(req.destroyed).toBe(true);
+  });
+});

src/utils/httpBody.ts

@@ -0,0 +1,65 @@
+import type { IncomingMessage } from 'http';
+
+export interface ReadRequestBodyOptions {
+  maxBytes: number;
+}
+
+export class RequestBodyTooLargeError extends Error {
+  readonly maxBytes: number;
+  readonly receivedBytes: number;
+
+  constructor(maxBytes: number, receivedBytes: number) {
+    super(`Request body too large (${receivedBytes} bytes > ${maxBytes} bytes)`);
+    this.name = 'RequestBodyTooLargeError';
+    this.maxBytes = maxBytes;
+    this.receivedBytes = receivedBytes;
+  }
+}
+
+/** Read the full request body with an explicit max-size limit. */
+export function readRequestBody(req: IncomingMessage, opts: ReadRequestBodyOptions): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const chunks: Buffer[] = [];
+    let totalBytes = 0;
+    let settled = false;
+
+    const cleanup = () => {
+      req.off('data', onData);
+      req.off('end', onEnd);
+      req.off('error', onError);
+    };
+
+    const fail = (err: Error) => {
+      if (settled) {return;}
+      settled = true;
+      cleanup();
+      reject(err);
+    };
+
+    const onData = (chunk: Buffer | string) => {
+      const buf = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
+      totalBytes += buf.length;
+      if (totalBytes > opts.maxBytes) {
+        if (typeof req.destroy === 'function') {
+          req.destroy();
+        }
+        fail(new RequestBodyTooLargeError(opts.maxBytes, totalBytes));
+        return;
+      }
+      chunks.push(buf);
+    };
+
+    const onEnd = () => {
+      if (settled) {return;}
+      settled = true;
+      cleanup();
+      resolve(Buffer.concat(chunks).toString('utf-8'));
+    };
+
+    const onError = (err: Error) => fail(err);
+
+    req.on('data', onData);
+    req.on('end', onEnd);
+    req.on('error', onError);
+  });
+}