🛡️ Sentinel: [CRITICAL] Fix ACE vulnerability in _safe_eval_type string evaluation

.jules/sentinel.md

@@ -4,3 +4,7 @@
 **Vulnerability:** Found an unused `_attempt_import` function in `src/codeweaver/server/mcp/server.py` that dynamically imports a module directly from unvalidated configuration (`import_module(mw.rsplit(".", 1)[0])`), leading to potential arbitrary code execution.
 **Learning:** Functions that perform dynamic imports should not be left around in the codebase if they are unused, especially if they are designed to take unvalidated strings as input.
 **Prevention:** Avoid dynamic imports based on configuration or inputs without strict whitelisting. Use tools like `semgrep` with python security rules to actively catch these patterns.
+## 2026-04-22 - Restricting ast.Call to Prevent Arbitrary Code Execution during Type String Eval
+**Vulnerability:** The AST validation logic in `_safe_eval_type` (`src/codeweaver/core/di/container.py`) permitted generic `ast.Call` nodes. Since the subsequent evaluation used `eval()` with the module's global namespace, this allowed for Arbitrary Code Execution (ACE) if an attacker could inject an arbitrary function call into a string-based type annotation.
+**Learning:** Even when limiting builtins, evaluating strings as code (`eval`) with access to an entire module's namespace is inherently risky. `ast.Call` nodes must be strictly constrained.
+**Prevention:** Whitelist `ast.Call` nodes specifically to the required subset of safe, metadata-constructing functions (e.g., `Depends`, `Field`, `Parameter`). Never allow unrestrained function calls when dynamically resolving type annotations.

src/codeweaver/core/di/container.py

@@ -84,7 +84,7 @@ def __init__(self) -> None:
         self._request_cache: dict[Any, Any] = {}  # Keys can be types or callables
         self._providers_loaded: bool = False  # Track if auto-discovery has run
 
-    def _safe_eval_type(self, type_str: str, globalns: dict[str, Any]) -> Any | None:
+    def _safe_eval_type(self, type_str: str, globalns: dict[str, Any]) -> Any | None:  # noqa: C901
         """Safely evaluate a type string using AST validation.
 
         Parses the type string into an AST, validates that it contains only safe
@@ -136,6 +136,19 @@ def generic_visit(self, node: ast.AST) -> None:
                 if isinstance(node, ast.Attribute) and node.attr.startswith("__"):
                     raise TypeError(f"Forbidden dunder attribute: {node.attr}")
 
+                # Restricting generic ast.Call nodes to a strict whitelist prevents Arbitrary Code
+                # Execution (ACE) vulnerabilities during type string resolution.
+                if isinstance(node, ast.Call):
+                    allowed_calls = {"Depends", "depends", "Field", "PrivateAttr", "Tag", "Parameter"}
+                    func_name = None
+                    if isinstance(node.func, ast.Name):
+                        func_name = node.func.id
+                    elif isinstance(node.func, ast.Attribute):
+                        func_name = node.func.attr
+
+                    if func_name not in allowed_calls:
+                        raise TypeError(f"Forbidden function call in type string: {func_name}")
+
                 super().generic_visit(node)
 
         try: