1 files changed, 14 insertions, 5 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 865d75214a9a..9e1bd374875e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -928,23 +928,32 @@ static int udp_encap_rcv(struct sock * sk, struct sk_buff *skb)
         return 1; 
 #else
         struct udp_sock *up = udp_sk(sk);
-        struct udphdr *uh = skb->h.uh;
+        struct udphdr *uh;
         struct iphdr *iph;
         int iphlen, len;
   
-        __u8 *udpdata = (__u8 *)uh + sizeof(struct udphdr);
-        __be32 *udpdata32 = (__be32 *)udpdata;
+        __u8 *udpdata;
+        __be32 *udpdata32;
         __u16 encap_type = up->encap_type;
 
         /* if we're overly short, let UDP handle it */
-        if (udpdata > skb->tail)
+        len = skb->len - sizeof(struct udphdr);
+        if (len <= 0)
                 return 1;
 
         /* if this is not encapsulated socket, then just return now */
         if (!encap_type)
                 return 1;
 
-        len = skb->tail - udpdata;
+        /* If this is a paged skb, make sure we pull up
+         * whatever data we need to look at. */
+        if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
+                return 1;
+
+        /* Now we can get the pointers */
+        uh = skb->h.uh;
+        udpdata = (__u8 *)uh + sizeof(struct udphdr);
+        udpdata32 = (__be32 *)udpdata;
 
         switch (encap_type) {
         default: