xtables: fix segfault if incorrect protocol name is used

This patch fixes a segfault that can be triggered if you use an
incorrect protocol, e.g.

# iptables -I PREROUTING -t nat -p lalala --dport 21 -j DNAT --to 192.168.1.2:21
Segmentation fault

With this patch:

# iptables -I PREROUTING -t nat -p lalala --dport 21 -j DNAT --to 192.168.1.2:21
iptables v1.4.3.2: unknown protocol `lala' specified
Try `iptables -h' or 'iptables --help' for more information

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed