[PATCH AUTOSEL for 4.9 085/293] ip_tunnel: fix potential issue in ip_tunnel_rcv

[Sasha Levin]

From: Haishuang Yan <yanhaishu...@cmss.chinamobile.com>

[ Upstream commit 469f87e158628fe66dcbbce9dd5e7b7acfe934a9 ]

When ip_tunnel_rcv fails, the tun_dst won't be freed, so call
dst_release to free it in error code path.

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Acked-by: Eric Dumazet <eduma...@google.com>
Acked-by: Pravin B Shelar <pshe...@ovn.org>
Tested-by: Zhang Shengju <zhangshen...@cmss.chinamobile.com>
Signed-off-by: Haishuang Yan <yanhaishu...@cmss.chinamobile.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 net/ipv4/ip_tunnel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 96536a0d6e2d..a665eaab5db2 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -439,6 +439,8 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff 
*skb,
        return 0;
 
 drop:
+       if (tun_dst)
+               dst_release((struct dst_entry *)tun_dst);
        kfree_skb(skb);
        return 0;
 }
-- 
2.15.1