ndisc: Check NS message length before access.

Check message length before accessing "target" field,
as we do for other types.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 429622d74705..350f86005c13 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -671,6 +671,11 @@ static void ndisc_recv_ns(struct sk_buff *skb)
         bool inc;
         int is_router = -1;
 
+        if (skb->len < sizeof(struct nd_msg)) {
+                ND_PRINTK(2, warn, "NS: packet too short\n");
+                return;
+        }
+
         if (ipv6_addr_is_multicast(&msg->target)) {
                 ND_PRINTK(2, warn, "NS: multicast target address\n");
                 return;