From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 1/3] netfilter: xt_TCPOPTSTRIP: don't use tcp_hdr() Date: Mon, 17 Jun 2013 21:34:37 +0200 Message-ID: <1371497679-14314-2-git-send-email-pablo@netfilter.org> References: <1371497679-14314-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: In-Reply-To: <1371497679-14314-1-git-send-email-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org 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 --- net/netfilter/xt_TCPOPTSTRIP.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/netfilter/xt_TCPOPTSTRIP.c b/net/netfilter/xt_TCPOPTSTRIP.c index 1eb1a44..b68fa19 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; /* -- 1.7.10.4