Coverity scan on python2 resulted in this error.

Python-2.7.15/Modules/_ctypes/cfield.c:1297: alloc_fn: Storage is returned from allocation function "PyString_FromString".
Python-2.7.15/Objects/stringobject.c:143:5: alloc_fn: Storage is returned from allocation function "PyObject_Malloc".
Python-2.7.15/Objects/obmalloc.c:982:5: alloc_fn: Storage is returned from allocation function "malloc".
Python-2.7.15/Objects/obmalloc.c:982:5: return_alloc_fn: Directly returning storage allocated by "malloc".
Python-2.7.15/Objects/stringobject.c:143:5: var_assign: Assigning: "op" = "PyObject_Malloc(37UL + size)".
Python-2.7.15/Objects/stringobject.c:164:5: return_alloc: Returning allocated memory "op".
Python-2.7.15/Modules/_ctypes/cfield.c:1297: var_assign: Assigning: "result" = storage returned from "PyString_FromString((char *)ptr)".
Python-2.7.15/Modules/_ctypes/cfield.c:1311: leaked_storage: Variable "result" going out of scope leaks the storage it points to.
1309|       } else
1310|           /* cannot shorten the result */
1311|->         return PyString_FromStringAndSize(ptr, size);
1312|   }
1313|   

This was fixed on python3 with https://github.com/python/cpython/commit/19b52545df898ec911c44e29f75badb902924c0b

Partially backporting this change for this file should fix the issue.

Also the change from PyUnicode_FromStringAndSize to PyBytes_FromStringAndSize happened here: https://bugs.python.org/issue8966

New changeset 098b139816f379271b8d4de2561b5805dd47d229 by Victor Stinner (stratakis) in branch '2.7':
bpo-36147: Fix a memory leak in ctypes s_get() (GH-12102)
https://github.com/python/cpython/commit/098b139816f379271b8d4de2561b5805dd47d229

Thanks Charalampos Stratakis!