ip_tunnel: Fix dst ref-count.

Commit 10ddceb22ba (ip_tunnel:multicast process cause panic due
to skb->_skb_refdst NULL pointer) removed dst-drop call from
ip-tunnel-recv.

Following commit reintroduce dst-drop and fix the original bug by
checking loopback packet before releasing dst.
Original bug: https://bugzilla.kernel.org/show_bug.cgi?id=70681

CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 1863422..250be74 100644 (file)
--- 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;
 

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 78a89e6..a82a22d 100644 (file)
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -416,9 +416,6 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 
 #ifdef CONFIG_NET_IPGRE_BROADCAST
        if (ipv4_is_multicast(iph->daddr)) {
-               /* Looped back packet, drop it! */
-               if (rt_is_output_route(skb_rtable(skb)))
-                       goto drop;
                tunnel->dev->stats.multicast++;
                skb->pkt_type = PACKET_BROADCAST;
        }

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 6f847dd..8d69626 100644 (file)
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -108,6 +108,7 @@ int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
        nf_reset(skb);
        secpath_reset(skb);
        skb_clear_hash_if_not_l4(skb);
+       skb_dst_drop(skb);
        skb->vlan_tci = 0;
        skb_set_queue_mapping(skb, 0);
        skb->pkt_type = PACKET_HOST;