Dynamic (#77)

tests/dynamic_fixtures/deserialize/python/benign.py

@@ -0,0 +1,22 @@
+"""Phase 03 (Track J.1) — Python deserialize benign fixture.
+
+Wraps `pickle.Unpickler` with a `find_class` override that hard-codes
+a tiny allowlist.  A gadget chain in the payload trips
+`UnpicklingError` before any code runs, so no Deserialize probe
+fires.
+"""
+import io
+import pickle
+
+ALLOWED = {("builtins", "list"), ("builtins", "dict"), ("builtins", "int")}
+
+
+class RestrictedUnpickler(pickle.Unpickler):
+    def find_class(self, module: str, name: str):
+        if (module, name) not in ALLOWED:
+            raise pickle.UnpicklingError(f"blocked: {module}.{name}")
+        return super().find_class(module, name)
+
+
+def run(blob: bytes):
+    return RestrictedUnpickler(io.BytesIO(blob)).load()

tests/dynamic_fixtures/deserialize/python/vuln.py

@@ -0,0 +1,11 @@
+"""Phase 03 (Track J.1) — Python deserialize vuln fixture.
+
+`pickle.loads` accepts arbitrary classes; a gadget chain inside the
+payload runs straight through `__reduce__` without bumping into any
+allowlist.
+"""
+import pickle
+
+
+def run(blob: bytes):
+    return pickle.loads(blob)