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>
diff --git a/xtables.c b/xtables.c
index a01d4ea..e018331 100644
--- a/xtables.c
+++ b/xtables.c
@@ -1502,6 +1502,9 @@
else {
unsigned int i;
for (i = 0; i < ARRAY_SIZE(xtables_chain_protos); ++i) {
+ if (xtables_chain_protos[i].name == NULL)
+ continue;
+
if (strcmp(s, xtables_chain_protos[i].name) == 0) {
proto = xtables_chain_protos[i].num;
break;