apply security audit

backend/src/services/authentik.service.ts

@@ -1,9 +1,23 @@
 import axios, { AxiosError } from 'axios';
+import * as jose from 'jose';
 import authentikConfig from '../config/authentik';
 import logger from '../utils/logger';
 import { TokenResponse, UserInfo } from '../types/auth.types';
 
 class AuthentikService {
+  private jwks: ReturnType<typeof jose.createRemoteJWKSet> | null = null;
+
+  private getJwks(): ReturnType<typeof jose.createRemoteJWKSet> {
+    if (!this.jwks) {
+      // Derive JWKS URI from the issuer URL
+      // Issuer: https://auth.example.com/application/o/myapp/
+      // JWKS:   https://auth.example.com/application/o/myapp/jwks/
+      const jwksUri = new URL('jwks/', authentikConfig.issuer.endsWith('/') ? authentikConfig.issuer : authentikConfig.issuer + '/');
+      this.jwks = jose.createRemoteJWKSet(jwksUri);
+    }
+    return this.jwks;
+  }
+
   /**
    * Exchange authorization code for access and ID tokens
    */
@@ -61,48 +75,26 @@ class AuthentikService {
   }
 
   /**
-   * Verify and decode ID token (basic validation)
-   * Note: For production, use a proper JWT verification library like jose or jsonwebtoken
+   * Verify and decode ID token using JWKS
    */
-  verifyIdToken(idToken: string): any {
+  async verifyIdToken(idToken: string): Promise<jose.JWTPayload> {
     try {
-      // Split the token into parts
-      const parts = idToken.split('.');
-      if (parts.length !== 3) {
-        throw new Error('Invalid ID token format');
-      }
+      const { payload } = await jose.jwtVerify(idToken, this.getJwks(), {
+        issuer: authentikConfig.issuer,
+      });
 
-      // Decode the payload (Base64URL)
-      const payload = JSON.parse(
-        Buffer.from(parts[1], 'base64url').toString('utf-8')
-      );
-
-      // Basic validation
       if (!payload.sub || !payload.email) {
-        throw new Error('Invalid ID token payload');
+        throw new Error('Invalid ID token payload: missing sub or email');
       }
 
-      // Check expiration
-      if (payload.exp && payload.exp * 1000 < Date.now()) {
-        throw new Error('ID token has expired');
-      }
-
-      // Check issuer
-      if (payload.iss && !payload.iss.includes(authentikConfig.issuer)) {
-        logger.warn('ID token issuer mismatch', {
-          expected: authentikConfig.issuer,
-          received: payload.iss,
-        });
-      }
-
-      logger.info('ID token verified successfully', {
+      logger.info('ID token verified successfully via JWKS', {
         sub: payload.sub,
         email: payload.email,
       });
 
       return payload;
     } catch (error) {
-      logger.error('Failed to verify ID token', { error });
+      logger.error('Failed to verify ID token via JWKS', { error });
       throw new Error('Invalid ID token');
     }
   }