FunctionParser: convert previous_names protobuf field to a plain list. (#6584)

angr/knowledge_plugins/functions/function_parser.py

@@ -216,7 +216,7 @@ class FunctionParser:
         obj.info = json.loads(cmsg.info.decode("utf-8")) if cmsg.info else {}
         obj.is_default_name = cmsg.is_default_name
         obj.ran_cca = cmsg.ran_cca
-        obj.previous_names = cmsg.previous_names
+        obj.previous_names = list(cmsg.previous_names)
 
         # signature matched?
         if cmsg.matched_from == function_pb2.Function.UNMATCHED:

tests/knowledge_plugins/functions/test_function_parser_previous_names.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+# pylint: disable=missing-class-docstring
+"""Regression test: parse_from_cmsg assigned the protobuf RepeatedScalarContainer
+directly to Function.previous_names instead of converting it to a plain list.
+This breaks pickling of Function objects.
+"""
+
+from __future__ import annotations
+
+import pickle
+import tempfile
+import unittest
+
+import angr
+from angr.codenode import BlockNode
+from angr.knowledge_plugins.functions.function import Function
+
+
+class TestFunctionParserPreviousNames(unittest.TestCase):
+    def test_parsed_previous_names_is_plain_list_and_picklable(self):
+        blob = bytes.fromhex("c3")  # ret
+        addr = 0x400000
+
+        with tempfile.NamedTemporaryFile(suffix=".bin", delete=False) as f:
+            f.write(blob)
+            blob_path = f.name
+
+        proj = angr.Project(
+            blob_path,
+            main_opts={
+                "backend": "blob",
+                "base_addr": addr,
+                "arch": "AMD64",
+                "entry_point": addr,
+            },
+            auto_load_libs=False,
+        )
+
+        fm = proj.kb.functions
+        func = fm.function(addr=addr, create=True)
+        assert func is not None
+        func._register_node(True, BlockNode(addr, 1, bytestr=blob))
+        func.name = "original_name"
+        func.name = "renamed"  # records "original_name" in previous_names
+        self.assertIn("original_name", func.previous_names)
+        expected = list(func.previous_names)
+
+        cmsg = func.serialize_to_cmessage()
+        loaded = Function.parse_from_cmessage(cmsg, function_manager=fm, project=proj)
+
+        # previous_names must be a plain list, not a live protobuf container
+        self.assertIs(type(loaded.previous_names), list)
+        self.assertEqual(loaded.previous_names, expected)
+
+        # mutating the parsed function must not alias back into the cmsg
+        loaded.previous_names.append("another_name")
+        self.assertEqual(list(cmsg.previous_names), expected)
+
+        # the parsed function must round-trip through pickle
+        unpickled = pickle.loads(pickle.dumps(loaded))
+        self.assertEqual(unpickled.previous_names, [*expected, "another_name"])
+
+
+if __name__ == "__main__":
+    unittest.main()