From 73766b0341674f3920f4ea86a6f8288b801960f9 Mon Sep 17 00:00:00 2001 From: Zackery Spytz Date: Sun, 2 May 2021 03:40:01 -0700 Subject: [PATCH] bpo-32745: Fix a regression in the handling of ctypes' c_wchar_p type (#8721) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Embedded nulls would cause a ValueError to be raised. Thanks go to Eryk Sun for their analysis. Co-authored-by: Łukasz Langa --- Lib/ctypes/test/test_unicode.py | 8 ++++++++ .../next/Library/2018-08-09-23-47-10.bpo-32745.iQi9hI.rst | 3 +++ Modules/_ctypes/cfield.c | 3 ++- 3 files changed, 13 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Library/2018-08-09-23-47-10.bpo-32745.iQi9hI.rst diff --git a/Lib/ctypes/test/test_unicode.py b/Lib/ctypes/test/test_unicode.py index c200af7b650661..60c75424b767fa 100644 --- a/Lib/ctypes/test/test_unicode.py +++ b/Lib/ctypes/test/test_unicode.py @@ -26,6 +26,14 @@ def test_buffers(self): self.assertEqual(buf[::2], 'a\xe4\xfc') self.assertEqual(buf[6:5:-1], "") + def test_embedded_null(self): + class TestStruct(ctypes.Structure): + _fields_ = [("unicode", ctypes.c_wchar_p)] + t = TestStruct() + # This would raise a ValueError: + t.unicode = "foo\0bar\0\0" + + func = ctypes.CDLL(_ctypes_test.__file__)._testfunc_p_p class StringTestCase(UnicodeTestCase): diff --git a/Misc/NEWS.d/next/Library/2018-08-09-23-47-10.bpo-32745.iQi9hI.rst b/Misc/NEWS.d/next/Library/2018-08-09-23-47-10.bpo-32745.iQi9hI.rst new file mode 100644 index 00000000000000..e6a60fe8da140b --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-08-09-23-47-10.bpo-32745.iQi9hI.rst @@ -0,0 +1,3 @@ +Fix a regression in the handling of ctypes' :data:`ctypes.c_wchar_p` type: +embedded null characters would cause a :exc:`ValueError` to be raised. Patch +by Zackery Spytz. diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c index d96a1b0651baad..8d0710fbabcca3 100644 --- a/Modules/_ctypes/cfield.c +++ b/Modules/_ctypes/cfield.c @@ -1341,6 +1341,7 @@ Z_set(void *ptr, PyObject *value, Py_ssize_t size) { PyObject *keep; wchar_t *buffer; + Py_ssize_t bsize; if (value == Py_None) { *(wchar_t **)ptr = NULL; @@ -1364,7 +1365,7 @@ Z_set(void *ptr, PyObject *value, Py_ssize_t size) /* We must create a wchar_t* buffer from the unicode object, and keep it alive */ - buffer = PyUnicode_AsWideCharString(value, NULL); + buffer = PyUnicode_AsWideCharString(value, &bsize); if (!buffer) return NULL; keep = PyCapsule_New(buffer, CTYPES_CFIELD_CAPSULE_NAME_PYMEM, pymem_destructor);