SF #633013, Fix NIS causing interpreter core dump

Prevent the lengths passed to PyString_FromStringAndSize()
from being negative in some cases.

diff --git a/Modules/nismodule.c b/Modules/nismodule.c
index f66e9a1cc67f1ee05caad14239de0cdaa7f5ed21..0a38ee85c5a34c70c0be5969e4cb58c9a6fcdbc0 100644 (file)
--- a/Modules/nismodule.c
+++ b/Modules/nismodule.c
@@ -85,8 +85,10 @@ nis_foreach (int instatus, char *inkey, int inkeylen, char *inval,
                int err;
 
                if (indata->fix) {
-                   inkeylen--;
-                   invallen--;
+                   if (inkeylen > 0 && inkey[inkeylen-1] == '\0')
+                       inkeylen--;
+                   if (invallen > 0 && inval[invallen-1] == '\0')
+                       invallen--;
                }
                key = PyString_FromStringAndSize(inkey, inkeylen);
                val = PyString_FromStringAndSize(inval, invallen);