net: check for underlength tap writes

If the user gives a packet under 14 bytes, we'll end up reading off the end
of the skb (not oopsing, just reading off the end).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Max Krasnyanskiy <maxk@qualcomm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rusty Russell 2008-04-12 18:49:30 -07:00 committed by David S. Miller
parent 14daa02139
commit e01bf1c833

View File

@ -286,8 +286,11 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
return -EFAULT;
}
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
align = NET_IP_ALIGN;
if (unlikely(len < ETH_HLEN))
return -EINVAL;
}
if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
tun->dev->stats.rx_dropped++;