ipv6: check raw payload size correctly in ioctl
authorJamie Bainbridge <jbainbri@redhat.com>
Wed, 26 Apr 2017 00:43:27 +0000 (10:43 +1000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 26 Apr 2017 18:59:35 +0000 (14:59 -0400)
In situations where an skb is paged, the transport header pointer and
tail pointer can be the same because the skb contents are in frags.

This results in ioctl(SIOCINQ/FIONREAD) incorrectly returning a
length of 0 when the length to receive is actually greater than zero.

skb->len is already correctly set in ip6_input_finish() with
pskb_pull(), so use skb->len as it always returns the correct result
for both linear and paged data.

Signed-off-by: Jamie Bainbridge <jbainbri@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv6/raw.c

index f174e76e6505d4045e940c9fceef765d2aaa937d..0da6a12b5472e322d679572c7244e5c9bc467741 100644 (file)
@@ -1178,8 +1178,7 @@ static int rawv6_ioctl(struct sock *sk, int cmd, unsigned long arg)
                spin_lock_bh(&sk->sk_receive_queue.lock);
                skb = skb_peek(&sk->sk_receive_queue);
                if (skb)
-                       amount = skb_tail_pointer(skb) -
-                               skb_transport_header(skb);
+                       amount = skb->len;
                spin_unlock_bh(&sk->sk_receive_queue.lock);
                return put_user(amount, (int __user *)arg);
        }