[IPSEC]: Use the correct ip_local_out function

From: Herbert Xu <herbert@gondor.apana.org.au>
To: "David S. Miller" <davem@davemloft.net>,
	Marco Berizzi <pupilla@hotmail.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [IPSEC]: Use the correct ip_local_out function
Date: Tue, 20 May 2008 17:25:11 +0800	[thread overview]
Message-ID: <20080520092511.GA9005@gondor.apana.org.au> (raw)
In-Reply-To: <BAY103-DAV88950FC99CDE9EAAE27B2B2CE0@phx.gbl>

On Wed, May 14, 2008 at 10:19:57AM +0200, Marco Berizzi wrote:
> 
> I hope this helps.

OK found the problem, it was my fault after all :)

Dave, this patch needs to go into stable too.

[IPSEC]: Use the correct ip_local_out function

Because the IPsec output function xfrm_output_resume does its
own dst_output call it should always call __ip_local_output
instead of ip_local_output as the latter may invoke dst_output
directly.  Otherwise the return values from nf_hook and dst_output
may clash as they both use the value 1 but for different purposes.

When that clash occurs this can cause a packet to be used after
it has been freed which usually leads to a crash.  Because the
offending value is only returned from dst_output with qdiscs
such as HTB, this bug is normally not visible.

Thanks to Marco Berizzi for his perseverance in tracking this
down.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Cheers,
-- 
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diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 92f90ae..df41026 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -160,7 +160,7 @@ static struct dst_ops ipv4_dst_ops = {
 	.negative_advice =	ipv4_negative_advice,
 	.link_failure =		ipv4_link_failure,
 	.update_pmtu =		ip_rt_update_pmtu,
-	.local_out =		ip_local_out,
+	.local_out =		__ip_local_out,
 	.entry_size =		sizeof(struct rtable),
 	.entries =		ATOMIC_INIT(0),
 };
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 12bba08..849b78a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -109,7 +109,7 @@ static struct dst_ops ip6_dst_ops_template = {
 	.negative_advice	=	ip6_negative_advice,
 	.link_failure		=	ip6_link_failure,
 	.update_pmtu		=	ip6_rt_update_pmtu,
-	.local_out		=	ip6_local_out,
+	.local_out		=	__ip6_local_out,
 	.entry_size		=	sizeof(struct rt6_info),
 	.entries		=	ATOMIC_INIT(0),
 };
