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authorPablo Neira Ayuso <pablo@netfilter.org>2013-06-11 01:51:31 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2013-06-11 01:55:07 +0200
commited82c437320c48a4032492f4a55a7e2c934158b6 (patch)
treef86328e2d8d222989322f0a9d65e04218f3e531f /net
parenta8241c63517ec0b900695daa9003cddc41c536a1 (diff)
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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 <fw@strlen.de> Reported-by: Phil Oester <kernel@linuxace.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/xt_TCPOPTSTRIP.c6
1 files changed, 4 insertions, 2 deletions
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;
/*