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| author |   Serhiy Storchaka <storchaka@gmail.com> | 2021-07-29 14:36:24 +0300 |
|---|---|---|
| committer |   GitHub <noreply@github.com> | 2021-07-29 12:36:24 +0100 |
| commit | e5c8ddb1714fb51ab1defa24352c98e0f01205dc (patch) | |
| tree | e5204f644e0019a5a32f24081c343426df1ba485 | |
| parent | bpo-41103: Resurrect the old buffer protocol. (GH-27437) (diff) | |
| download | cpython-e5c8ddb1714fb51ab1defa24352c98e0f01205dc.tar.gz cpython-e5c8ddb1714fb51ab1defa24352c98e0f01205dc.tar.bz2 cpython-e5c8ddb1714fb51ab1defa24352c98e0f01205dc.zip | |
bpo-44707: Fix an undefined behavior of the null pointer arithmetic (GH-27292)
| -rw-r--r-- | Objects/listobject.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/Objects/listobject.c b/Objects/listobject.c index 6eb7dce759c..898cbc20c5f 100644 --- a/Objects/listobject.c +++ b/Objects/listobject.c @@ -180,9 +180,10 @@ PyList_New(Py_ssize_t size) static PyObject * list_new_prealloc(Py_ssize_t size) { + assert(size > 0); PyListObject *op = (PyListObject *) PyList_New(0); - if (size == 0 || op == NULL) { - return (PyObject *) op; + if (op == NULL) { + return NULL; } assert(op->ob_item == NULL); op->ob_item = PyMem_New(PyObject *, size); @@ -459,6 +460,9 @@ list_slice(PyListObject *a, Py_ssize_t ilow, Py_ssize_t ihigh) PyObject **src, **dest; Py_ssize_t i, len; len = ihigh - ilow; + if (len <= 0) { + return PyList_New(0); + } np = (PyListObject *) list_new_prealloc(len); if (np == NULL) return NULL; @@ -512,6 +516,9 @@ list_concat(PyListObject *a, PyObject *bb) #define b ((PyListObject *)bb) assert((size_t)Py_SIZE(a) + (size_t)Py_SIZE(b) < PY_SSIZE_T_MAX); size = Py_SIZE(a) + Py_SIZE(b); + if (size == 0) { + return PyList_New(0); + } np = (PyListObject *) list_new_prealloc(size); if (np == NULL) { return NULL; |