From c0420fd42ade6d996bfe2ae2beffa3de79524883 Mon Sep 17 00:00:00 2001 From: Mark Dickinson Date: Mon, 19 Sep 2011 19:18:37 +0100 Subject: Issue #12973: Fix undefined-behaviour-inducing overflow check in list_repeat. --- Misc/NEWS | 4 ++++ Objects/listobject.c | 6 +++--- 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); -- cgit v0.12