From: Dmitry Popov <dp@highloadlab.com>
To: Jan Engelhardt <jengelh@gmx.de>
Cc: netfilter-devel@vger.kernel.org
Subject: [PATCH] xtables-addons: xt_RAWNAT: skb writable part might not include whole l4 header (ipv4 case).
Date: Sun, 5 May 2013 22:05:04 +0400 [thread overview]
Message-ID: <20130505220504.1a3f2380a1e798b37e628dd1@highloadlab.com> (raw)
Consider TCP/IPv4 packet with IP options:
sizeof(*iph) + sizeof(struct tcphdr) is not enough to include tcp checksum.
It may hurt if this packet is fragmented.
Therefore we should use iph->ihl * 4 instead of sizeof(*iph).
Signed-off-by: Dmitry Popov <dp@highloadlab.com>
---
extensions/xt_RAWNAT.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/extensions/xt_RAWNAT.c b/extensions/xt_RAWNAT.c
index a52e614..858f911 100644
--- a/extensions/xt_RAWNAT.c
+++ b/extensions/xt_RAWNAT.c
@@ -109,7 +109,7 @@ static void rawnat4_update_l4(struct sk_buff *skb, __be32 oldip, __be32 newip)
static unsigned int rawnat4_writable_part(const struct iphdr *iph)
{
- unsigned int wlen = sizeof(*iph);
+ unsigned int wlen = iph->ihl * 4;
switch (iph->protocol) {
case IPPROTO_TCP:
next reply other threads:[~2013-05-05 18:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-05 18:05 Dmitry Popov [this message]
2013-05-05 18:24 ` [PATCH] xtables-addons: xt_RAWNAT: skb writable part might not include whole l4 header (ipv4 case) Dmitry Popov
2013-05-08 11:32 ` Jan Engelhardt
2013-05-08 15:12 ` Dmitry Popov
2013-05-08 21:32 ` Jan Engelhardt
2013-05-13 9:50 ` Dmitry Popov
2013-05-15 15:04 ` Pablo Neira Ayuso
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