It's very unlikely, though possible that source is not a string. Verify
that PyString_AsString() returns a valid pointer. (The problem can
arise when zlib.decompress doesn't return a string.)
Klocwork 346
diff --git a/Modules/zipimport.c b/Modules/zipimport.c
index d59ebd8..69b2881 100644
--- a/Modules/zipimport.c
+++ b/Modules/zipimport.c
@@ -950,6 +950,9 @@
char *buf, *q, *p = PyString_AsString(source);
PyObject *fixed_source;
+ if (!p)
+ return NULL;
+
/* one char extra for trailing \n and one for terminating \0 */
buf = (char *)PyMem_Malloc(PyString_Size(source) + 2);
if (buf == NULL) {