tun: Fix use-after-free on XDP_TX

On XDP_TX we need to free up the frame only when tun_xdp_tx() returns a
negative value. A positive value indicates that the packet is
successfully enqueued to the ptr_ring, so freeing the page causes
use-after-free.

Fixes: 735fc4054b ("xdp: change ndo_xdp_xmit API to support bulking")
Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Toshiaki Makita 2018-07-13 13:24:38 +09:00 committed by David S. Miller
parent 9f80a0723b
commit 6e8cfd6d9d

View file

@ -1688,7 +1688,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
case XDP_TX:
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
if (tun_xdp_tx(tun->dev, &xdp))
if (tun_xdp_tx(tun->dev, &xdp) < 0)
goto err_redirect;
rcu_read_unlock();
local_bh_enable();