fix: restrict CORS to explicit methods and add security headers

- Replace allow_methods=["*"] with explicit list: GET, POST, PUT, DELETE, PATCH, OPTIONS
- Replace allow_headers=["*"] with explicit list: Content-Type, Authorization, Accept, Origin, X-Requested-With
- Add X-Frame-Options, X-Content-Type-Options, Referrer-Policy, CSP nginx headers

Co-Authored-By: Paperclip <noreply@paperclip.ing>

api/src/cartsnitch_api/middleware/cors.py

@@ -11,6 +11,6 @@ def add_cors_middleware(app: FastAPI) -> None:
         CORSMiddleware,
         allow_origins=settings.cors_origins,
         allow_credentials=True,
-        allow_methods=["*"],
+        allow_methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"],
-        allow_headers=["*"],
+        allow_headers=["Content-Type", "Authorization", "Accept", "Origin", "X-Requested-With"],
     )

nginx.conf

@@ -9,6 +9,12 @@ server {
     gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript image/svg+xml;
     gzip_min_length 256;
 
+    # Security headers
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
+    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self'; connect-src 'self' https://*.cartsnitch.com https://*.farh.net; frame-ancestors 'self'" always;
+
     # Health endpoint for K8s probes
     location /health {
         access_log off;