(proxy) - Auth fix, ensure re-using safe request body for checking model field (#7222)

* litellm fix auth check

* fix _read_request_body

* test_auth_with_form_data_and_model

* fix auth check

* fix _read_request_body

* fix _safe_get_request_headers

litellm/proxy/auth/user_api_key_auth.py

@@ -899,12 +899,10 @@ async def user_api_key_auth(  # noqa: PLR0915
                 # the validation will occur when checking the team has access to this model
                 pass
             else:
-                try:
-                    data = await request.json()
-                except json.JSONDecodeError:
-                    data = {}  # Provide a default value, such as an empty dictionary
-                model = data.get("model", None)
-                fallback_models: Optional[List[str]] = data.get("fallbacks", None)
+                model = request_data.get("model", None)
+                fallback_models: Optional[List[str]] = request_data.get(
+                    "fallbacks", None
+                )
 
                 if model is not None:
                     await can_key_call_model(

litellm/proxy/common_utils/http_parsing_utils.py

@@ -21,19 +21,23 @@ async def _read_request_body(request: Optional[Request]) -> Dict:
     try:
         if request is None:
             return {}
+        _request_headers: dict = _safe_get_request_headers(request=request)
+        content_type = _request_headers.get("content-type", "")
+        if "form" in content_type:
+            return dict(await request.form())
+        else:
+            # Read the request body
+            body = await request.body()
 
-        # Read the request body
-        body = await request.body()
+            # Return empty dict if body is empty or None
+            if not body:
+                return {}
 
-        # Return empty dict if body is empty or None
-        if not body:
-            return {}
+            # Decode the body to a string
+            body_str = body.decode()
 
-        # Decode the body to a string
-        body_str = body.decode()
-
-        # Attempt JSON parsing (safe for untrusted input)
-        return json.loads(body_str)
+            # Attempt JSON parsing (safe for untrusted input)
+            return json.loads(body_str)
 
     except json.JSONDecodeError:
         # Log detailed information for debugging
@@ -48,6 +52,21 @@ async def _read_request_body(request: Optional[Request]) -> Dict:
         return {}
 
 
+def _safe_get_request_headers(request: Optional[Request]) -> dict:
+    """
+    [Non-Blocking] Safely get the request headers
+    """
+    try:
+        if request is None:
+            return {}
+        return dict(request.headers)
+    except Exception as e:
+        verbose_proxy_logger.exception(
+            "Unexpected error reading request headers - {}".format(e)
+        )
+        return {}
+
+
 def check_file_size_under_limit(
     request_data: dict,
     file: UploadFile,

tests/proxy_unit_tests/test_user_api_key_auth.py

@@ -496,3 +496,57 @@ def test_read_request_body():
     request.body = return_body
     result = _read_request_body(request)
     assert result is not None
+
+
+@pytest.mark.asyncio
+async def test_auth_with_form_data_and_model():
+    """
+    Test user_api_key_auth when:
+    1. Request has form data instead of JSON body
+    2. Virtual key has a model set
+    """
+    from fastapi import Request
+    from starlette.datastructures import URL, FormData
+    from litellm.proxy.proxy_server import (
+        hash_token,
+        user_api_key_cache,
+        user_api_key_auth,
+    )
+
+    # Setup
+    user_key = "sk-12345678"
+
+    # Create a virtual key with a specific model
+    valid_token = UserAPIKeyAuth(
+        token=hash_token(user_key),
+        models=["gpt-4"],
+    )
+
+    # Store the virtual key in cache
+    user_api_key_cache.set_cache(key=hash_token(user_key), value=valid_token)
+
+    setattr(litellm.proxy.proxy_server, "user_api_key_cache", user_api_key_cache)
+    setattr(litellm.proxy.proxy_server, "master_key", "sk-1234")
+    setattr(litellm.proxy.proxy_server, "prisma_client", "hello-world")
+
+    # Create request with form data
+    request = Request(
+        scope={
+            "type": "http",
+            "method": "POST",
+            "headers": [(b"content-type", b"application/x-www-form-urlencoded")],
+        }
+    )
+    request._url = URL(url="/chat/completions")
+
+    # Mock form data
+    form_data = FormData([("key1", "value1"), ("key2", "value2")])
+
+    async def return_form_data():
+        return form_data
+
+    request.form = return_form_data
+
+    # Test user_api_key_auth with form data request
+    response = await user_api_key_auth(request=request, api_key="Bearer " + user_key)
+    assert response.models == ["gpt-4"], "Model from virtual key should be preserved"