ipv6: fix crash over flow-based vxlan device

Similar check was added in ip_rcv but not in ipv6_rcv.

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff81734e0a>] ipv6_rcv+0xfa/0x500
Call Trace:
[<ffffffff816c9786>] ? ip_rcv+0x296/0x400
[<ffffffff817732d2>] ? packet_rcv+0x52/0x410
[<ffffffff8168e99f>] __netif_receive_skb_core+0x63f/0x9a0
[<ffffffffc02b34a0>] ? br_handle_frame_finish+0x580/0x580 [bridge]
[<ffffffff8109912c>] ? update_rq_clock.part.81+0x1c/0x40
[<ffffffff8168ed18>] __netif_receive_skb+0x18/0x60
[<ffffffff8168fa1f>] process_backlog+0x9f/0x150

Fixes: ee122c79d422 (vxlan: Flow based tunneling)
Signed-off-by: Wei-Chun Chao <weichunc@plumgrid.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 57990c929cd8156ebac52c648deb50fd3f74ab82..adba03ac7ce9671f6dba419d163672b9520743bd 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -45,6 +45,7 @@
 #include <net/addrconf.h>
 #include <net/xfrm.h>
 #include <net/inet_ecn.h>
+#include <net/dst_metadata.h>
 
 int ip6_rcv_finish(struct sock *sk, struct sk_buff *skb)
 {
@@ -55,7 +56,7 @@ int ip6_rcv_finish(struct sock *sk, struct sk_buff *skb)
                if (ipprot && ipprot->early_demux)
                        ipprot->early_demux(skb);
        }
-       if (!skb_dst(skb))
+       if (!skb_valid_dst(skb))
                ip6_route_input(skb);
 
        return dst_input(skb);
@@ -98,7 +99,7 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
         * arrived via the sending interface (ethX), because of the
         * nature of scoping architecture. --yoshfuji
         */
-       IP6CB(skb)->iif = skb_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
+       IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
 
        if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
                goto err;