#13096: Fix segfault in CTypes POINTER handling of large values.

Patch by Meador Inge.

1 files changed, 7 insertions, 2 deletions

diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 6642dc3f4c..19f59e0c9e 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1807,7 +1807,9 @@ POINTER(PyObject *self, PyObject *cls)
         return result;
     }
     if (PyString_CheckExact(cls)) {
-        buf = alloca(strlen(PyString_AS_STRING(cls)) + 3 + 1);
+        buf = PyMem_Malloc(strlen(PyString_AS_STRING(cls)) + 3 + 1);
+        if (buf == NULL)
+            return PyErr_NoMemory();
         sprintf(buf, "LP_%s", PyString_AS_STRING(cls));
         result = PyObject_CallFunction((PyObject *)Py_TYPE(&PyCPointer_Type),
                                        "s(O){}",
@@ -1818,13 +1820,16 @@ POINTER(PyObject *self, PyObject *cls)
         key = PyLong_FromVoidPtr(result);
     } else if (PyType_Check(cls)) {
         typ = (PyTypeObject *)cls;
-        buf = alloca(strlen(typ->tp_name) + 3 + 1);
+        buf = PyMem_Malloc(strlen(typ->tp_name) + 3 + 1);
+        if (buf == NULL)
+            return PyErr_NoMemory();
         sprintf(buf, "LP_%s", typ->tp_name);
         result = PyObject_CallFunction((PyObject *)Py_TYPE(&PyCPointer_Type),
                                        "s(O){sO}",
                                        buf,
                                        &PyCPointer_Type,
                                        "_type_", cls);
+        PyMem_Free(buf);
         if (result == NULL)
             return result;
         Py_INCREF(cls);