From 2a9de3af21aa8c31cd68b0b39330d69f8c1e59df Mon Sep 17 00:00:00 2001
From: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Date: Wed, 11 Mar 2020 11:19:06 +0100
Subject: [PATCH] vti6: Fix memory leak of skb if input policy check fails
Git-commit: 2a9de3af21aa8c31cd68b0b39330d69f8c1e59df
Patch-mainline: v5.6
References: git-fixes

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

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

diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 56e642efefff..cc6180e08a4f 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -311,7 +311,7 @@ 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);
-- 
2.16.4