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

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()