potential nullptr dereference + use of uninitialized memory in fileutils

[maxbachmann]

Bug report

cpython/Python/fileutils.c

Lines 2161 to 2162 in 6daf42b

	join_relfile(filename, bufsize, dirname, relfile);
	return filename;

can lead to use of uninitialized memory when join_relfile fails.

cpython/Python/fileutils.c

Lines 2197 to 2199 in 6daf42b

	_Py_normpath(wchar_t *path, Py_ssize_t size)
	{
	if (!path[0] || size == 0) {

in combination with

cpython/Modules/getpath.c

Line 450 in 6daf42b

path2 = _Py_normpath(_Py_join_relfile(path, resolved), -1);

leads to a nullptr dereference.

Linked PRs

• gh-102281: fix potential nullptr dereference + use of uninitialized memory #102282
• [3.11] gh-102281: Fix potential nullptr dereference + use of uninitia… #103040

[hauntsaninja]

Thanks for the fix! Looks like this could still use backports

[maxbachmann]

Thanks for the reminder

[hauntsaninja]

Thanks again :-)