[3.8] bpo-35714: Reject null characters in struct format strings (GH-16928) (GH-20419)

struct.error is now raised if there is a null character in a struct
format string.
(cherry picked from commit 3f59b55316f4c6ab451997902579aa69020b537c)

1 files changed, 7 insertions, 0 deletions

diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
index 454082e..67e7c55 100644
--- a/Lib/test/test_struct.py
+++ b/Lib/test/test_struct.py
@@ -652,6 +652,13 @@ class StructTest(unittest.TestCase):
         s2 = struct.Struct(s.format.encode())
         self.assertEqual(s2.format, s.format)
 
+    def test_issue35714(self):
+        # Embedded null characters should not be allowed in format strings.
+        for s in '\0', '2\0i', b'\0':
+            with self.assertRaisesRegex(struct.error,
+                                        'embedded null character'):
+                struct.calcsize(s)
+
 
 class UnpackIteratorTest(unittest.TestCase):
     """