fix(security): apply per-IP rate limiting to credential endpoints

The five authRateLimiter registrations were inert for the same reason the general one was -- registered below the error handler. Auth endpoints have never had an IP limit; the 5-attempt behaviour QA observed is the per-account lockout in authSecurity.js, which is a different mechanism and is untouched. They could not simply be activated: app.use('/api/auth', ...) is a prefix, so a 5-per-window budget would have covered GET /api/auth/session and POST /api/auth/password-strength, which the frontend calls far more than five times per window. That locks users out. The real surface was enumerated by loading the routers and walking router.stack rather than grepping, which showed two of the five registrations pointed at routes that do not exist: adminAuth.js has no /login (admin login is POST /api/auth/admin/login) and there is no /api/gallery/:slug/verify (gallery verify is POST /api/auth/gallery/verify). Now limited, on exact method+path: admin login, admin MFA verify, gallery password verify, share-login, client PIN, setup verify-token, setup admin, customer login, customer password-reset. Deliberately unlimited: session checks, password-strength, logouts, authenticated change-password, the SSO round-trip (a 429 on the callback breaks login from shared corporate IPs), and one-time invite/accept-invite links. Two choices carry the design. skipSuccessfulRequests means only failed attempts spend budget, which is what makes 5-per-IP survivable behind NAT -- ten guests on one venue wifi all typing the correct gallery password consume nothing -- and means a legitimate admin cannot be locked out by their own success. And the limiter keeps its own rateLimit() instance, hence its own store and its own per-IP bucket, with the general gate's auth exemption left in place: sharing a counter is exactly the lockout described above. Patterns are case-insensitive because Express's case-sensitive routing is off by default, so POST /api/auth/admin/LOGIN reaches the login handler and a case-sensitive pattern would have been a free bypass. max is now read per request, so the Settings UI's rate_limit_auth_max_requests applies without a restart, matching the general limiter. Tests prove both directions: each credential endpoint 429s on attempt 6 with the response shape the four login pages already branch on, each benign endpoint still returns 200 after 40 calls, the two buckets are independent in both directions, and 30 consecutive successful logins consume no budget. Refs testplan REPORT.md, rate-limiter gap.
2026-09-02 09:43:11 +02:00
parent 30ac4140af
commit 50e8ed6e58
5 changed files with 426 additions and 23 deletions
@@ -0,0 +1,293 @@
+/**
+ * The credential endpoints need a per-IP limit — and nothing else may get one.
+ *
+ * The five `app.use('/api/auth', authRateLimiter)`-style registrations inside
+ * initializeRateLimiters() were inert for the same reason the general limiter
+ * was: they run after the routers and the error handler are already mounted.
+ * They could not just be moved up, either — `/api/auth` is a prefix, so a
+ * 5-per-window budget would have covered GET /api/auth/session and POST
+ * /api/auth/password-strength, which the frontend calls far more than five
+ * times per window. Moving them as written would have locked users out.
+ *
+ * So these tests pin both directions: the credential endpoints ARE limited,
+ * and the benign high-frequency endpoints under the same prefixes are NOT,
+ * even after many times the auth budget. Plus the two properties that make the
+ * budget survivable in production — only failures count, and the auth bucket is
+ * separate from the general /api bucket.
+ *
+ * The source half pins registration DEPTH, which is what was broken and which
+ * no unit test of the gate itself can catch.
+ */
+const fs = require('fs');
+const path = require('path');
+const express = require('express');
+const request = require('supertest');
+
+let mockSettingsRows = [];
+
+jest.mock('../../src/database/db', () => ({
+  db: jest.fn(() => ({
+    whereIn: jest.fn().mockImplementation(() => Promise.resolve(mockSettingsRows))
+  }))
+}));
+
+jest.mock('../../src/utils/logger', () => ({
+  info: jest.fn(), warn: jest.fn(), error: jest.fn(), debug: jest.fn()
+}));
+
+const { createAuthRateLimitGate } = require('../../src/middleware/authRateLimitGate');
+const { createApiRateLimitGate } = require('../../src/middleware/apiRateLimitGate');
+const {
+  createAuthRateLimiter,
+  createRateLimiter,
+  clearSettingsCache
+} = require('../../src/services/rateLimitService');
+
+const setting = (key, value) => ({ setting_key: key, setting_value: JSON.stringify(value) });
+
+// Mirrors the real stack: gates above the routers, unmounted so req.path keeps
+// its /api prefix. `loginSucceeds` lets a test drive the skipSuccessfulRequests
+// behaviour without a database.
+let loginSucceeds = false;
+
+function mountRoutes(app) {
+  const fail = (res) => res.status(401).json({ error: 'Invalid credentials' });
+
+  // Credential endpoints — the group that must be limited.
+  app.post('/api/auth/admin/login', (req, res) =>
+    (loginSucceeds ? res.json({ user: {} }) : fail(res)));
+  app.post('/api/auth/admin/login/mfa', (req, res) => fail(res));
+  app.post('/api/auth/gallery/verify', (req, res) => fail(res));
+  app.post('/api/auth/gallery/share-login', (req, res) => fail(res));
+  app.post('/api/auth/gallery/:slug/client-login', (req, res) => fail(res));
+  app.post('/api/setup/verify-token', (req, res) => fail(res));
+  app.post('/api/setup/admin', (req, res) => fail(res));
+  app.post('/api/customer/auth/login', (req, res) => fail(res));
+  app.post('/api/customer/auth/password-reset', (req, res) => fail(res));
+
+  // Benign endpoints living under the very same prefixes the old registrations
+  // covered. Every one of these is called more than five times per window by a
+  // normal session.
+  app.get('/api/auth/session', (req, res) => res.json({ authenticated: false }));
+  app.post('/api/auth/password-strength', (req, res) => res.json({ score: 3 }));
+  app.post('/api/auth/logout', (req, res) => res.json({ ok: true }));
+  app.post('/api/auth/gallery/logout', (req, res) => res.json({ ok: true }));
+  app.post('/api/auth/admin/change-password', (req, res) => res.json({ ok: true }));
+  app.get('/api/auth/admin/sso/callback', (req, res) => res.json({ ok: true }));
+  app.get('/api/setup/status', (req, res) => res.json({ needsSetup: false }));
+  app.get('/api/customer/auth/session', (req, res) => res.json({ ok: true }));
+  app.get('/api/gallery/:slug/verify-token/:token', (req, res) => res.json({ valid: true }));
+  app.get('/api/public/settings', (req, res) => res.json({ ok: true }));
+}
+
+async function buildApp({ withGeneralGate = false } = {}) {
+  const app = express();
+  if (withGeneralGate) {
+    const generalLimiter = await createRateLimiter();
+    app.use(createApiRateLimitGate(() => generalLimiter));
+  }
+  const authLimiter = await createAuthRateLimiter();
+  app.use(createAuthRateLimitGate(() => authLimiter));
+  app.use(express.json());
+  mountRoutes(app);
+  return app;
+}
+
+beforeEach(() => {
+  mockSettingsRows = [];
+  loginSucceeds = false;
+  clearSettingsCache();
+});
+
+describe('authRateLimitGate — credential endpoints are limited', () => {
+  it('429s admin login on the 6th failed attempt in the window', async () => {
+    const app = await buildApp();
+    for (let i = 0; i < 5; i++) {
+      expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    }
+    const blocked = await request(app).post('/api/auth/admin/login').send({});
+    expect(blocked.status).toBe(429);
+    // Shape the frontend already branches on (AdminLoginPage, GalleryPage,
+    // CustomerLoginPage and SetupPage all check status === 429).
+    expect(blocked.body.error).toBe('Too many authentication attempts, please try again later.');
+    expect(blocked.headers['ratelimit-limit']).toBe('5');
+  });
+
+  it.each([
+    ['/api/auth/admin/login/mfa'],
+    ['/api/auth/gallery/verify'],
+    ['/api/auth/gallery/share-login'],
+    ['/api/auth/gallery/some-slug/client-login'],
+    ['/api/setup/verify-token'],
+    ['/api/setup/admin'],
+    ['/api/customer/auth/login'],
+    ['/api/customer/auth/password-reset']
+  ])('429s %s once the budget is spent', async (endpoint) => {
+    const app = await buildApp();
+    for (let i = 0; i < 5; i++) {
+      expect((await request(app).post(endpoint).send({})).status).toBe(401);
+    }
+    expect((await request(app).post(endpoint).send({})).status).toBe(429);
+  });
+
+  it('shares one budget across the credential endpoints, so spraying is bounded', async () => {
+    const app = await buildApp();
+    const sprayed = [
+      '/api/auth/admin/login',
+      '/api/auth/gallery/verify',
+      '/api/customer/auth/login',
+      '/api/setup/verify-token',
+      '/api/auth/gallery/share-login'
+    ];
+    for (const endpoint of sprayed) {
+      expect((await request(app).post(endpoint).send({})).status).toBe(401);
+    }
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(429);
+  });
+
+  it('honours rate_limit_auth_max_requests from app_settings', async () => {
+    mockSettingsRows = [setting('rate_limit_auth_max_requests', 2)];
+    const app = await buildApp();
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(429);
+  });
+
+  it('does nothing when rate_limit_enabled is false', async () => {
+    mockSettingsRows = [setting('rate_limit_enabled', false)];
+    const app = await buildApp();
+    for (let i = 0; i < 20; i++) {
+      expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    }
+  });
+
+  it('only counts failures, so successful logins never consume the budget', async () => {
+    // This is what makes a 5-per-window per-IP budget safe behind NAT: a room
+    // of guests on one venue IP who all type the right password count zero.
+    const app = await buildApp();
+    loginSucceeds = true;
+    for (let i = 0; i < 30; i++) {
+      expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(200);
+    }
+    // The budget is still fully intact for real failures.
+    loginSucceeds = false;
+    for (let i = 0; i < 5; i++) {
+      expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    }
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(429);
+  });
+
+  it('passes through during the boot window, before the limiter exists', async () => {
+    const app = express();
+    app.use(createAuthRateLimitGate(() => undefined));
+    mountRoutes(app);
+    for (let i = 0; i < 10; i++) {
+      expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    }
+  });
+});
+
+describe('authRateLimitGate — benign endpoints are never limited', () => {
+  // 40 calls each: eight times the 5-per-window auth budget. Every one of these
+  // would have been covered by the old app.use('/api/auth', ...) prefix.
+  it.each([
+    ['GET', '/api/auth/session'],
+    ['POST', '/api/auth/password-strength'],
+    ['POST', '/api/auth/logout'],
+    ['POST', '/api/auth/gallery/logout'],
+    ['POST', '/api/auth/admin/change-password'],
+    ['GET', '/api/auth/admin/sso/callback'],
+    ['GET', '/api/setup/status'],
+    ['GET', '/api/customer/auth/session'],
+    ['GET', '/api/gallery/some-slug/verify-token/abc']
+  ])('%s %s stays available after 40 calls', async (method, endpoint) => {
+    const app = await buildApp();
+    for (let i = 0; i < 40; i++) {
+      const res = await request(app)[method.toLowerCase()](endpoint).send({});
+      expect(res.status).toBe(200);
+    }
+  });
+
+  it('does not treat a GET on a credential path as an attempt', async () => {
+    // The table is method-specific: only the POST spends budget.
+    const app = await buildApp();
+    for (let i = 0; i < 20; i++) {
+      // No GET handler is mounted, so a 404 proves the gate let it through
+      // rather than answering 429.
+      expect((await request(app).get('/api/auth/admin/login')).status).toBe(404);
+    }
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+  });
+
+  it('matches case-insensitively, since Express routing is case-insensitive', async () => {
+    const app = await buildApp();
+    for (let i = 0; i < 5; i++) {
+      expect((await request(app).post('/api/auth/admin/LOGIN').send({})).status).toBe(401);
+    }
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(429);
+  });
+});
+
+describe('authRateLimitGate — its bucket is independent of the general /api bucket', () => {
+  it('an exhausted general budget still leaves the login budget intact', async () => {
+    mockSettingsRows = [
+      setting('rate_limit_max_requests', 3),
+      setting('rate_limit_auth_max_requests', 5)
+    ];
+    const app = await buildApp({ withGeneralGate: true });
+
+    for (let i = 0; i < 3; i++) {
+      expect((await request(app).get('/api/public/settings')).status).toBe(200);
+    }
+    expect((await request(app).get('/api/public/settings')).status).toBe(429);
+
+    // The exact failure the old wiring would have produced: the branding and
+    // settings fetches a login page makes before anyone types a password
+    // 429ing the login itself. Separate stores mean it cannot happen.
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+  });
+
+  it('an exhausted login budget still leaves the general budget intact', async () => {
+    mockSettingsRows = [
+      setting('rate_limit_max_requests', 3),
+      setting('rate_limit_auth_max_requests', 5)
+    ];
+    const app = await buildApp({ withGeneralGate: true });
+
+    for (let i = 0; i < 5; i++) {
+      expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(401);
+    }
+    expect((await request(app).post('/api/auth/admin/login').send({})).status).toBe(429);
+
+    for (let i = 0; i < 3; i++) {
+      expect((await request(app).get('/api/public/settings')).status).toBe(200);
+    }
+  });
+});
+
+describe('server.js — the auth gate is registered above the routers', () => {
+  const source = fs.readFileSync(path.resolve(__dirname, '../../server.js'), 'utf8');
+  const lines = source.split('\n');
+  const lineOf = (re) => {
+    const i = lines.findIndex((l) => re.test(l));
+    expect(i).toBeGreaterThan(-1);
+    return i;
+  };
+
+  it('registers the gate before the first router mount', () => {
+    expect(lineOf(/createAuthRateLimitGate\(/))
+      .toBeLessThan(lineOf(/^app\.use\('\/api\/setup'/));
+  });
+
+  it('registers the gate unmounted, so req.path keeps its /api prefix', () => {
+    expect(source).toMatch(/app\.use\(createAuthRateLimitGate\(/);
+  });
+
+  it('no longer registers authRateLimiter on a prefix from initializeRateLimiters', () => {
+    // This is the regression: an app.use() there runs after the error handler
+    // and can never see a request — and '/api/auth' as a prefix would have
+    // covered GET /api/auth/session at the 5-per-window auth budget.
+    expect(source).not.toMatch(/app\.use\('\/api\/auth',\s*authRateLimiter\)/);
+    expect(source).not.toMatch(/app\.use\('[^']*',\s*authRateLimiter\)/);
+  });
+});