[PATCH v2,net-next 2/2] ip6_gre: fix potential memory leak in ip6erspan_rcv

[Haishuang Yan]

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

Fixes: ef7baf5e083c ("ip6_gre: add ip6 erspan collect_md mode")
Cc: William Tu <u9012063@xxxxxxxxx>
Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>

Change since v2:
  * Rebase on latest master branch.
  * Correct wrong fix information.
---
 net/ipv6/ip6_gre.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 5c9c65f..8ce9d42 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -549,8 +549,10 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
 
 			info = &tun_dst->u.tun_info;
 			md = ip_tunnel_info_opts(info);
-			if (!md)
+			if (!md) {
+				dst_release((struct dst_entry *)tun_dst);
 				return PACKET_REJECT;
+			}
 
 			memcpy(md, pkt_md, sizeof(*md));
 			md->version = ver;
-- 
1.8.3.1