netdev - [PATCH nf 1/6] ipvs: fix ipv6 route unreach panic

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Message-Id: <1437012853-7318-2-git-send-email-horms@verge.net.au>
Date:	Thu, 16 Jul 2015 11:14:08 +0900
From:	Simon Horman <horms@...ge.net.au>
To:	Pablo Neira Ayuso <pablo@...filter.org>
Cc:	lvs-devel@...r.kernel.org, netdev@...r.kernel.org,
	netfilter-devel@...r.kernel.org,
	Wensong Zhang <wensong@...ux-vs.org>,
	Julian Anastasov <ja@....bg>, Alex Gartrell <agartrell@...com>,
	Simon Horman <horms@...ge.net.au>
Subject: [PATCH nf 1/6] ipvs: fix ipv6 route unreach panic

From: Alex Gartrell <agartrell@...com>

Previously there was a trivial panic

unshare -n /bin/bash <<EOF
ip addr add dev lo face::1/128
ipvsadm -A -t [face::1]:15213
ipvsadm -a -t [face::1]:15213 -r b00c::1
echo boom | nc face::1 15213
EOF

This patch allows us to replicate the net logic above and simply capture
the skb_dst(skb)->dev and use that for the purpose of the invocation.

Signed-off-by: Alex Gartrell <agartrell@...com>
Acked-by: Julian Anastasov <ja@....bg>
Signed-off-by: Simon Horman <horms@...ge.net.au>
---
 net/netfilter/ipvs/ip_vs_xmit.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index bf66a8657a5f..b99d80695b1f 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -505,6 +505,13 @@ err_put:
 	return -1;
 
 err_unreach:
+	/* The ip6_link_failure function requires the dev field to be set
+	 * in order to get the net (further for the sake of fwmark
+	 * reflection).
+	 */
+	if (!skb->dev)
+		skb->dev = skb_dst(skb)->dev;
+
 	dst_link_failure(skb);
 	return -1;
 }
-- 
2.1.4

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