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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Torsten Hilbrich <torsten.hilbrich@secunet.com>,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        Steffen Klassert <steffen.klassert@secunet.com>
Subject: [PATCH 4.9 070/102] vti6: Fix memory leak of skb if input policy check fails
Date:   Wed,  1 Apr 2020 18:18:13 +0200
Message-Id: <20200401161544.369456064@linuxfoundation.org>
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From: Torsten Hilbrich <torsten.hilbrich@secunet.com>

commit 2a9de3af21aa8c31cd68b0b39330d69f8c1e59df upstream.

The vti6_rcv function performs some tests on the retrieved tunnel
including checking the IP protocol, the XFRM input policy, the
source and destination address.

In all but one places the skb is released in the error case. When
the input policy check fails the network packet is leaked.

Using the same goto-label discard in this case to fix this problem.

Fixes: ed1efb2aefbb ("ipv6: Add support for IPsec virtual tunnel interfaces")
Signed-off-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/ipv6/ip6_vti.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -315,7 +315,7 @@ static int vti6_rcv(struct sk_buff *skb)
 
 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 			rcu_read_unlock();
-			return 0;
+			goto discard;
 		}
 
 		ipv6h = ipv6_hdr(skb);