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: 735fc4054b3a ("xdp: change ndo_xdp_xmit API to support bulking")
Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
---
drivers/net/tun.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a192a01..f5727ba 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -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();
--
1.8.3.1
