[3.12] gh-105979: Fix exception handling in unmarshal_frozen_code (Python/import.c) (GH-105980) (#106055)

gh-105979: Fix exception handling in `unmarshal_frozen_code` (`Python/import.c`) (GH-105980)
(cherry picked from commit cd52803)

Co-authored-by: chgnrdv <[email protected]>

Author: miss-islington

Lib/test/test_import/__init__.py

@@ -23,6 +23,7 @@
 import unittest
 from unittest import mock
 import _testinternalcapi
+import _imp
 
 from test.support import os_helper
 from test.support import (
@@ -763,6 +764,13 @@ def test_dll_dependency_import(self):
                                     env=env,
                                     cwd=os.path.dirname(pyexe))
 
+    def test_issue105979(self):
+        # this used to crash
+        with self.assertRaises(ImportError) as cm:
+            _imp.get_frozen_object("x", b"6\'\xd5Cu\x12")
+        self.assertIn("Frozen object named 'x' is invalid",
+                      str(cm.exception))
+
 
 @skip_if_dont_write_bytecode
 class FilePermissionTests(unittest.TestCase):

Misc/NEWS.d/next/Core and Builtins/2023-06-22-19-16-24.gh-issue-105979.TDP2CU.rst

@@ -0,0 +1 @@
+Fix crash in :func:`!_imp.get_frozen_object` due to improper exception handling.

Python/import.c

@@ -2053,6 +2053,7 @@ unmarshal_frozen_code(PyInterpreterState *interp, struct frozen_info *info)
     PyObject *co = PyMarshal_ReadObjectFromString(info->data, info->size);
     if (co == NULL) {
         /* Does not contain executable code. */
+        PyErr_Clear();
         set_frozen_error(FROZEN_INVALID, info->nameobj);
         return NULL;
     }