Suricata

Fixed by:

commit 06751ecd756cf77f9eb91e7fd53b10058c4dad01
Author: Eric Leblond <eric@regit.org>
Date:   Wed Nov 28 10:34:35 2012 +0100

    prelude: don't build string objet for NULL string

    prelude_string_set_ref don't like when it is called with a NULL
    parameter. This patch adds check for NULL value. This is formally
    good as there is no use of a NULL description.