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>

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 5c36b6745dbce6a96a5aa6b9fa914faf65e4fc74..90c9123078147e7f84d9be65d9d4bb57f2f301eb 100644 (file)
--- 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;