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authorJulian Anastasov <ja@ssi.bg>2011-05-29 23:42:29 +0300
committerPablo Neira Ayuso <pablo@netfilter.org>2011-06-06 01:36:46 +0200
commitd9be76f38526dccf84062e3ac3ed3a6a97698565 (patch)
treecc819ad8ffd4f11bf916d624010863d978874b30
parentb48e3c5c323fea08c12a340cbb8dcc8ca2431d5b (diff)
netfilter: nf_nat: fix crash in nf_nat_csum
Fix crash in nf_nat_csum when mangling packets in OUTPUT hook where skb->dev is not defined, it is set later before POSTROUTING. Problem happens for CHECKSUM_NONE. We can check device from rt but using CHECKSUM_PARTIAL should be safe (skb_checksum_help). Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-rw-r--r--net/ipv4/netfilter/nf_nat_helper.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index 99cfa28b6d3..ebc5f8894f9 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -160,7 +160,7 @@ static void nf_nat_csum(struct sk_buff *skb, const struct iphdr *iph, void *data
if (skb->ip_summed != CHECKSUM_PARTIAL) {
if (!(rt->rt_flags & RTCF_LOCAL) &&
- skb->dev->features & NETIF_F_V4_CSUM) {
+ (!skb->dev || skb->dev->features & NETIF_F_V4_CSUM)) {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_headroom(skb) +
skb_network_offset(skb) +