1 files changed, 8 insertions, 0 deletions

diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 1863422fb7d5..250be7421ab3 100644
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -182,6 +182,14 @@ static int gre_cisco_rcv(struct sk_buff *skb)
         int i;
         bool csum_err = false;
 
+#ifdef CONFIG_NET_IPGRE_BROADCAST
+        if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
+                /* Looped back packet, drop it! */
+                if (rt_is_output_route(skb_rtable(skb)))
+                        goto drop;
+        }
+#endif
+
         if (parse_gre_header(skb, &tpi, &csum_err) < 0)
                 goto drop;