Commit ed82c437 authored Jun 11, 2013 by Pablo Neira Ayuso

netfilter: xt_TCPOPTSTRIP: don't use tcp_hdr()



In (bc6bcb59 netfilter: xt_TCPOPTSTRIP: fix possible mangling beyond
packet boundary), the use of tcp_hdr was introduced. However, we
cannot assume that skb->transport_header is set for non-local packets.

Cc: Florian Westphal <fw@strlen.de>
Reported-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

parent a8241c63

net/netfilter/xt_TCPOPTSTRIP.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -48,11 +48,13 @@ tcpoptstrip_mangle_packet(struct sk_buff *skb,
		return NF_DROP;

		len = skb->len - tcphoff;
		if (len < (int)sizeof(struct tcphdr) \|\|
		tcp_hdr(skb)->doff * 4 > len)
		if (len < (int)sizeof(struct tcphdr))
		return NF_DROP;

		tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff);
		if (tcph->doff * 4 > len)
		return NF_DROP;

		opt = (u_int8_t *)tcph;

		/*