Commit f8556919 authored Dec 08, 2014 by Steffen Klassert

xfrm6: Fix the nexthdr offset in _decode_session6.



xfrm_decode_session() was originally designed for the
usage in the receive path where the correct nexthdr offset
is stored in IP6CB(skb)->nhoff. Over time this function
spread to code that is used in the output path (netfilter,
vti) where IP6CB(skb)->nhoff is not set. As a result, we
get a wrong nexthdr and the upper layer flow informations
are wrong. This can leed to incorrect policy lookups.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

parent de3b7a06

net/ipv6/xfrm6_policy.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -134,8 +134,14 @@ _decode_session6(struct sk_buff skb, struct flowi fl, int reverse)
		u16 offset = sizeof(*hdr);
		struct ipv6_opt_hdr *exthdr;
		const unsigned char *nh = skb_network_header(skb);
		u8 nexthdr = nh[IP6CB(skb)->nhoff];
		u16 nhoff = IP6CB(skb)->nhoff;
		int oif = 0;
		u8 nexthdr;

		if (!nhoff)
		nhoff = offsetof(struct ipv6hdr, nexthdr);

		nexthdr = nh[nhoff];

		if (skb_dst(skb))
		oif = skb_dst(skb)->dev->ifindex;

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