From: Pablo Neira Ayuso Date: Mon, 10 Jun 2013 23:51:31 +0000 (+0200) Subject: netfilter: xt_TCPOPTSTRIP: don't use tcp_hdr() X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=ed82c437320c48a4032492f4a55a7e2c934158b6;p=openwrt%2Fstaging%2Fblogic.git netfilter: xt_TCPOPTSTRIP: don't use tcp_hdr() In (bc6bcb5 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 Reported-by: Phil Oester Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/netfilter/xt_TCPOPTSTRIP.c b/net/netfilter/xt_TCPOPTSTRIP.c index 1eb1a44bfd3d..b68fa191710f 100644 --- a/net/netfilter/xt_TCPOPTSTRIP.c +++ b/net/netfilter/xt_TCPOPTSTRIP.c @@ -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; /*