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Commit d9be76f3 authored by Julian Anastasov's avatar Julian Anastasov Committed by Pablo Neira Ayuso
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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: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent b48e3c5c

net/ipv4/netfilter/nf_nat_helper.c

+1 −1
Original line number Diff line number Diff line
@@ -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) +