feat: replace fixed login rate limit with progressive lockout

Made-with: Cursor

.env.example

@@ -23,8 +23,7 @@ LLM_MAX_RETRIES=1
 LLM_TEMPERATURE=0.7
 LLM_MAX_TOKENS=2048
 
-# Rate limits
-RATE_LIMIT_LOGIN=5
+# Rate limits (login uses progressive lockout: 5/10/20 failed attempts -> 15m/1h/24h block)
 RATE_LIMIT_REGISTER=3
 RATE_LIMIT_FORGOT_PASSWORD=3
 RATE_LIMIT_VERIFY_EMAIL=5

src/config/env.ts

@@ -22,7 +22,6 @@ const envSchema = z.object({
   LLM_TEMPERATURE: z.coerce.number().min(0).max(2).default(0.7),
   LLM_MAX_TOKENS: z.coerce.number().default(2048),
 
-  RATE_LIMIT_LOGIN: z.coerce.number().default(5),
   RATE_LIMIT_REGISTER: z.coerce.number().default(3),
   RATE_LIMIT_FORGOT_PASSWORD: z.coerce.number().default(3),
   RATE_LIMIT_VERIFY_EMAIL: z.coerce.number().default(5),

src/plugins/rateLimit.ts

@@ -6,7 +6,6 @@ import { env } from '../config/env.js';
 declare module 'fastify' {
   interface FastifyInstance {
     rateLimitOptions: {
-      login: { max: number; timeWindow: string };
       register: { max: number; timeWindow: string };
       forgotPassword: { max: number; timeWindow: string };
       verifyEmail: { max: number; timeWindow: string };
@@ -18,7 +17,6 @@ declare module 'fastify' {
 
 const rateLimitPlugin: FastifyPluginAsync = async (app: FastifyInstance) => {
   const options = {
-    login: { max: env.RATE_LIMIT_LOGIN, timeWindow: '15 minutes' },
     register: { max: env.RATE_LIMIT_REGISTER, timeWindow: '1 hour' },
     forgotPassword: { max: env.RATE_LIMIT_FORGOT_PASSWORD, timeWindow: '1 hour' },
     verifyEmail: { max: env.RATE_LIMIT_VERIFY_EMAIL, timeWindow: '15 minutes' },

src/routes/auth.ts

@@ -1,5 +1,6 @@
 import type { FastifyInstance } from 'fastify';
 import { AuthService } from '../services/auth/auth.service.js';
+import { checkBlocked, clearOnSuccess, recordFailedAttempt } from '../utils/loginLockout.js';
 
 const registerSchema = {
   body: {
@@ -89,20 +90,43 @@ export async function authRoutes(app: FastifyInstance) {
 
   app.post(
     '/login',
-    { schema: loginSchema, config: { rateLimit: rateLimitOptions.login } },
+    {
+      schema: loginSchema,
+      preValidation: async (req, reply) => {
+        const ip = req.ip ?? 'unknown';
+        const { blocked, retryAfter } = await checkBlocked(app.redis, ip);
+        if (blocked) {
+          if (retryAfter !== undefined) {
+            reply.header('Retry-After', String(retryAfter));
+          }
+          return reply.status(429).send({
+            error: {
+              code: 'RATE_LIMIT_EXCEEDED',
+              message: 'Too many failed login attempts. Please try again later.',
+              retryAfter,
+            },
+          });
+        }
+      },
+    },
     async (req, reply) => {
       const body = req.body as { email: string; password: string };
       const userAgent = req.headers['user-agent'];
-      const ipAddress = req.ip;
+      const ip = req.ip ?? 'unknown';
 
-      const result = await authService.login({
-        email: body.email,
-        password: body.password,
-        userAgent,
-        ipAddress,
-      });
-
-      return reply.send(result);
+      try {
+        const result = await authService.login({
+          email: body.email,
+          password: body.password,
+          userAgent,
+          ipAddress: ip,
+        });
+        await clearOnSuccess(app.redis, ip);
+        return reply.send(result);
+      } catch (err) {
+        await recordFailedAttempt(app.redis, ip);
+        throw err;
+      }
     },
   );
 

src/utils/loginLockout.ts

@@ -0,0 +1,106 @@
+import type { Redis } from 'ioredis';
+
+const WINDOW_15M_SEC = 15 * 60;   // 900
+const WINDOW_1H_SEC = 60 * 60;   // 3600
+const WINDOW_24H_SEC = 24 * 60 * 60; // 86400
+
+const THRESHOLD_15M = 5;
+const THRESHOLD_1H = 10;
+const THRESHOLD_24H = 20;
+
+const BLOCK_15M_SEC = WINDOW_15M_SEC;
+const BLOCK_1H_SEC = WINDOW_1H_SEC;
+const BLOCK_24H_SEC = WINDOW_24H_SEC;
+
+const KEY_PREFIX = 'lockout';
+
+function key15m(ip: string): string {
+  return `${KEY_PREFIX}:15m:${ip}`;
+}
+function key1h(ip: string): string {
+  return `${KEY_PREFIX}:1h:${ip}`;
+}
+function key24h(ip: string): string {
+  return `${KEY_PREFIX}:24h:${ip}`;
+}
+function keyBlocked(ip: string): string {
+  return `${KEY_PREFIX}:blocked:${ip}`;
+}
+
+/**
+ * Check if the IP is currently blocked due to progressive login lockout.
+ * @returns { blocked: true, retryAfter } if blocked, { blocked: false } otherwise
+ */
+export async function checkBlocked(
+  redis: Redis,
+  ip: string
+): Promise<{ blocked: boolean; retryAfter?: number }> {
+  const blockedKey = keyBlocked(ip);
+  const ttl = await redis.ttl(blockedKey);
+  if (ttl > 0) {
+    return { blocked: true, retryAfter: ttl };
+  }
+  return { blocked: false };
+}
+
+const RECORD_SCRIPT = `
+  local c15 = redis.call('INCR', KEYS[1])
+  if redis.call('TTL', KEYS[1]) == -1 then redis.call('EXPIRE', KEYS[1], ARGV[1]) end
+  local c1h = redis.call('INCR', KEYS[2])
+  if redis.call('TTL', KEYS[2]) == -1 then redis.call('EXPIRE', KEYS[2], ARGV[2]) end
+  local c24 = redis.call('INCR', KEYS[3])
+  if redis.call('TTL', KEYS[3]) == -1 then redis.call('EXPIRE', KEYS[3], ARGV[3]) end
+  return {c15, c1h, c24}
+`;
+
+/**
+ * Record a failed login attempt. Increments counters and sets blocked key when thresholds are reached.
+ * Thresholds: 5 in 15m -> 15m block; 10 in 1h -> 1h block; 20 in 24h -> 24h block.
+ */
+export async function recordFailedAttempt(redis: Redis, ip: string): Promise<void> {
+  const k15 = key15m(ip);
+  const k1h = key1h(ip);
+  const k24 = key24h(ip);
+  const kBlocked = keyBlocked(ip);
+
+  const counts = (await redis.eval(
+    RECORD_SCRIPT,
+    3,
+    k15,
+    k1h,
+    k24,
+    String(WINDOW_15M_SEC),
+    String(WINDOW_1H_SEC),
+    String(WINDOW_24H_SEC)
+  )) as number[];
+
+  const count15m = counts[0] ?? 0;
+  const count1h = counts[1] ?? 0;
+  const count24h = counts[2] ?? 0;
+
+  let blockTtl = 0;
+  if (count24h >= THRESHOLD_24H) {
+    blockTtl = BLOCK_24H_SEC;
+  } else if (count1h >= THRESHOLD_1H) {
+    blockTtl = BLOCK_1H_SEC;
+  } else if (count15m >= THRESHOLD_15M) {
+    blockTtl = BLOCK_15M_SEC;
+  }
+
+  if (blockTtl > 0) {
+    await redis.setex(kBlocked, blockTtl, '1');
+  }
+}
+
+/**
+ * Clear all lockout counters and blocked state on successful login.
+ */
+export async function clearOnSuccess(redis: Redis, ip: string): Promise<void> {
+  const keys = [
+    key15m(ip),
+    key1h(ip),
+    key24h(ip),
+    keyBlocked(ip),
+  ];
+  await redis.del(...keys);
+}