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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Tobias Brunner <tobias@strongswan.org>,
        "David S . Miller" <davem@davemloft.net>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.15 007/124] ipv6: Reinject IPv6 packets if IPsec
 policy matches after SNAT
Thread-Topic: [PATCH AUTOSEL for 4.15 007/124] ipv6: Reinject IPv6 packets if
 IPsec policy matches after SNAT
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Date:   Mon, 19 Mar 2018 15:47:03 +0000
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From: Tobias Brunner <tobias@strongswan.org>

[ Upstream commit 09ee9dba9611cd382fd360a99ad1c2fa23bfdca8 ]

If SNAT modifies the source address the resulting packet might match
an IPsec policy, reinject the packet if that's the case.

The exact same thing is already done for IPv4.

Signed-off-by: Tobias Brunner <tobias@strongswan.org>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 net/ipv6/ip6_output.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 3763dc01e374..0f874b48c1b5 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -138,6 +138,14 @@ static int ip6_finish_output(struct net *net, struct s=
ock *sk, struct sk_buff *s
 		return ret;
 	}
=20
+#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
+	/* Policy lookup after SNAT yielded a new policy */
+	if (skb_dst(skb)->xfrm) {
+		IPCB(skb)->flags |=3D IPSKB_REROUTED;
+		return dst_output(net, sk, skb);
+	}
+#endif
+
 	if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
 	    dst_allfrag(skb_dst(skb)) ||
 	    (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
--=20
2.14.1