v1.7.12: security hardening — CORS fix, security headers, fail-closed rate limiter, OpenAPI docs disabled by default, config auth privacy, webhook validation

backend/config.py

@@ -76,6 +76,10 @@ class Settings(BaseSettings):
     RATE_LIMIT_REQUESTS: int = 120
     RATE_LIMIT_WINDOW_SECONDS: int = 60
 
+    # Security / docs exposure
+    DOCS_ENABLED: bool = False
+    METRICS_ALLOWED_IPS: str = "127.0.0.1,::1,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
+
 
 _settings = Settings()
 
@@ -127,3 +131,6 @@ WEBHOOK_CLIENT_SECRET = _settings.WEBHOOK_CLIENT_SECRET
 RATE_LIMIT_ENABLED = _settings.RATE_LIMIT_ENABLED
 RATE_LIMIT_REQUESTS = _settings.RATE_LIMIT_REQUESTS
 RATE_LIMIT_WINDOW_SECONDS = _settings.RATE_LIMIT_WINDOW_SECONDS
+
+DOCS_ENABLED = _settings.DOCS_ENABLED
+METRICS_ALLOWED_IPS = _settings.METRICS_ALLOWED_IPS

backend/main.py

@@ -1,4 +1,5 @@
 import asyncio
+import ipaddress
 import logging
 import os
 import time
@@ -7,7 +8,15 @@ from pathlib import Path
 
 import structlog
 from audit_trail import log_action
-from config import AI_FEATURES_ENABLED, AUTH_ENABLED, CORS_ORIGINS, ENABLE_PERIODIC_FETCH, FETCH_INTERVAL_MINUTES
+from config import (
+    AI_FEATURES_ENABLED,
+    AUTH_ENABLED,
+    CORS_ORIGINS,
+    DOCS_ENABLED,
+    ENABLE_PERIODIC_FETCH,
+    FETCH_INTERVAL_MINUTES,
+    METRICS_ALLOWED_IPS,
+)
 from database import setup_indexes
 from fastapi import FastAPI, HTTPException, Request
 from fastapi.middleware.cors import CORSMiddleware
@@ -51,20 +60,28 @@ def configure_logging():
 configure_logging()
 logger = structlog.get_logger("aoc.fetcher")
 
-app = FastAPI()
+# Disable OpenAPI docs in production by default
+app = FastAPI(
+    docs_url="/docs" if DOCS_ENABLED else None,
+    redoc_url="/redoc" if DOCS_ENABLED else None,
+    openapi_url="/openapi.json" if DOCS_ENABLED else None,
+)
 
-# CORS: warn if wildcard is used with auth enabled, but do not break deployments
+# CORS: when auth is enabled, never allow credentials with wildcard origins
 _effective_cors = CORS_ORIGINS
+_cors_credentials = True
 if AUTH_ENABLED and "*" in _effective_cors:
     logger.warning(
-        "CORS wildcard (*) is insecure when AUTH_ENABLED=true. Set CORS_ORIGINS to your actual origin(s) in production."
+        "CORS wildcard (*) is insecure with AUTH_ENABLED=true and allow_credentials. "
+        "Disabling credentials. Set CORS_ORIGINS to your actual origin(s)."
     )
+    _cors_credentials = False
 
 app.add_middleware(CorrelationIdMiddleware)
 app.add_middleware(
     CORSMiddleware,
     allow_origins=_effective_cors,
-    allow_credentials=True,
+    allow_credentials=_cors_credentials,
     allow_methods=["*"],
     allow_headers=["*"],
 )
@@ -81,7 +98,7 @@ async def prometheus_middleware(request: Request, call_next):
 
 
 @app.middleware("http")
-async def cache_control_middleware(request: Request, call_next):
+async def security_headers_middleware(request: Request, call_next):
     response = await call_next(request)
     # Prevent caching of HTML and API responses by default
     if request.url.path.startswith("/api/") or request.url.path in ("/", "/index.html"):
@@ -100,6 +117,13 @@ async def cache_control_middleware(request: Request, call_next):
             "img-src 'self' data:; "
             "font-src 'self' data:;"
         )
+    # Additional security headers
+    response.headers["X-Content-Type-Options"] = "nosniff"
+    response.headers["X-Frame-Options"] = "DENY"
+    response.headers["Referrer-Policy"] = "strict-origin-when-cross-origin"
+    response.headers["Permissions-Policy"] = (
+        "accelerometer=(), camera=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), payment=(), usb=()"
+    )
     return response
 
 
@@ -165,8 +189,39 @@ async def health_check():
         raise HTTPException(status_code=503, detail="Database unavailable") from exc
 
 
+def _client_ip(request: Request) -> str:
+    """Best-effort client IP: X-Forwarded-For first hop, or direct client host."""
+    forwarded = request.headers.get("x-forwarded-for")
+    if forwarded:
+        return forwarded.split(",")[0].strip()
+    return request.client.host if request.client else ""
+
+
+def _is_metrics_allowed(ip: str) -> bool:
+    """Check if IP is in the configured metrics allowlist."""
+    if not METRICS_ALLOWED_IPS:
+        return True
+    try:
+        client_addr = ipaddress.ip_address(ip)
+    except ValueError:
+        return False
+    for network in METRICS_ALLOWED_IPS.split(","):
+        network = network.strip()
+        if not network:
+            continue
+        try:
+            if client_addr in ipaddress.ip_network(network, strict=False):
+                return True
+        except ValueError:
+            continue
+    return False
+
+
 @app.get("/metrics")
-async def metrics():
+async def metrics(request: Request):
+    client_ip = _client_ip(request)
+    if not _is_metrics_allowed(client_ip):
+        raise HTTPException(status_code=403, detail="Forbidden")
     return Response(content=prometheus_metrics(), media_type="text/plain")
 
 

backend/rate_limiter.py

@@ -79,4 +79,5 @@ async def check_rate_limit(request: Request):
     except RateLimitExceeded:
         raise
     except Exception as exc:
-        logger.warning("Rate limiter Redis error; allowing request", error=str(exc))
+        logger.warning("Rate limiter Redis error; failing closed", error=str(exc))
+        raise RateLimitExceeded(retry_after=60) from None

backend/routes/config.py

@@ -18,8 +18,8 @@ def auth_config():
     logger.debug("Auth config requested", auth_enabled=AUTH_ENABLED)
     return {
         "auth_enabled": AUTH_ENABLED,
-        "tenant_id": AUTH_TENANT_ID,
-        "client_id": AUTH_CLIENT_ID,
+        "tenant_id": AUTH_TENANT_ID if AUTH_ENABLED else "",
+        "client_id": AUTH_CLIENT_ID if AUTH_ENABLED else "",
         "scope": AUTH_SCOPE,
         "redirect_uri": None,  # frontend uses window.location.origin by default
     }

backend/routes/webhooks.py

@@ -17,7 +17,15 @@ async def graph_webhook(request: Request):
     if validation_token:
         # Microsoft sends validationToken as a query param during subscription creation.
         # Echo it back as plain text to prove endpoint ownership.
-        return Response(content=validation_token, media_type="text/plain")
+        # Validate to prevent content injection if endpoint is hit directly.
+        if len(validation_token) > 1024 or not validation_token.isascii():
+            logger.warning("Invalid validationToken rejected", length=len(validation_token))
+            return Response(status_code=400)
+        return Response(
+            content=validation_token,
+            media_type="text/plain",
+            headers={"X-Content-Type-Options": "nosniff"},
+        )
 
     try:
         body = await request.json()

backend/tests/conftest.py

@@ -51,18 +51,32 @@ def client(mock_events_collection, mock_watermarks_collection, monkeypatch):
 
     # Mock Redis so tests don't require a running Redis server
     class FakeRedis:
+        _store = {}
+
         async def get(self, key):
-            return None
+            return self._store.get(key)
 
         async def setex(self, key, ttl, value):
+            self._store[key] = value
+
+        async def incr(self, key):
+            self._store[key] = self._store.get(key, 0) + 1
+            return self._store[key]
+
+        async def expire(self, key, ttl):
             pass
 
     async def fake_get_arq_pool():
         return FakeRedis()
 
+    async def fake_get_redis():
+        return FakeRedis()
+
     monkeypatch.setattr("redis_client.get_arq_pool", fake_get_arq_pool)
+    monkeypatch.setattr("redis_client.get_redis", fake_get_redis)
     monkeypatch.setattr("routes.ask.get_arq_pool", fake_get_arq_pool)
-    monkeypatch.setattr("routes.jobs.get_redis", fake_get_arq_pool)
+    monkeypatch.setattr("routes.jobs.get_redis", fake_get_redis)
+    monkeypatch.setattr("rate_limiter.get_redis", fake_get_redis)
 
     from main import app
 

backend/tests/test_api.py

@@ -268,7 +268,7 @@ def test_health(client):
 
 
 def test_metrics(client):
-    response = client.get("/metrics")
+    response = client.get("/metrics", headers={"X-Forwarded-For": "127.0.0.1"})
     assert response.status_code == 200
     assert "aoc_request_duration_seconds" in response.text