From 50670b6ee9bc4ae8f9ce3112b437987adf273245 Mon Sep 17 00:00:00 2001
From: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Date: Wed, 20 Dec 2017 10:07:00 +0800
Subject: [PATCH] ip_gre: fix potential memory leak in erspan_rcv

If md is NULL, tun_dst must be freed, otherwise it will cause memory
leak.

Fixes: 1a66a836da6 ("gre: add collect_md mode to ERSPAN tunnel")
Cc: William Tu <u9012063@gmail.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv4/ip_gre.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 5c36b6745dbce..90c9123078147 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -313,8 +313,10 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 				return PACKET_REJECT;
 
 			md = ip_tunnel_info_opts(&tun_dst->u.tun_info);
-			if (!md)
+			if (!md) {
+				dst_release((struct dst_entry *)tun_dst);
 				return PACKET_REJECT;
+			}
 
 			memcpy(md, pkt_md, sizeof(*md));
 			md->version = ver;
-- 
2.30.2