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-rw-r--r--Misc/NEWS4
-rw-r--r--Objects/listobject.c6
2 files changed, 7 insertions, 3 deletions
diff --git a/Misc/NEWS b/Misc/NEWS
index bfe5369..bc52aa8 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@ What's New in Python 3.2.3?
Core and Builtins
-----------------
+- Issue #12973: Fix overflow check that relied on undefined behaviour in
+ list_repeat. This bug caused test_list to fail with recent versions
+ of Clang.
+
- Issue #12802: the Windows error ERROR_DIRECTORY (numbered 267) is now
mapped to POSIX errno ENOTDIR (previously EINVAL).
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 73624f0..36f8b9d 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -58,7 +58,7 @@ list_resize(PyListObject *self, Py_ssize_t newsize)
if (newsize == 0)
new_allocated = 0;
items = self->ob_item;
- if (new_allocated <= ((~(size_t)0) / sizeof(PyObject *)))
+ if (new_allocated <= (PY_SIZE_MAX / sizeof(PyObject *)))
PyMem_RESIZE(items, PyObject *, new_allocated);
else
items = NULL;
@@ -510,9 +510,9 @@ list_repeat(PyListObject *a, Py_ssize_t n)
PyObject *elem;
if (n < 0)
n = 0;
- size = Py_SIZE(a) * n;
- if (n && size/n != Py_SIZE(a))
+ if (n > 0 && Py_SIZE(a) > PY_SSIZE_T_MAX / n)
return PyErr_NoMemory();
+ size = Py_SIZE(a) * n;
if (size == 0)
return PyList_New(0);
np = (PyListObject *) PyList_New(size);