4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Wang jasowang@redhat.com
[ Upstream commit 7063efd33bb15abc0160347f89eb5aba6b7d000e ]
After commit b196d88aba8a ("tun: fix use after free for ptr_ring") we need clean up tx ring during release(). But unfortunately, it tries to do the cleanup blindly after socket were destroyed which will lead another use-after-free. Fix this by doing the cleanup before dropping the last reference of the socket in __tun_detach().
Reported-by: Andrei Vagin avagin@virtuozzo.com Acked-by: Andrei Vagin avagin@virtuozzo.com Fixes: b196d88aba8a ("tun: fix use after free for ptr_ring") Signed-off-by: Jason Wang jasowang@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -728,6 +728,7 @@ static void __tun_detach(struct tun_file } if (tun) xdp_rxq_info_unreg(&tfile->xdp_rxq); + ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free); sock_put(&tfile->sk); } } @@ -3157,7 +3158,6 @@ static int tun_chr_close(struct inode *i struct tun_file *tfile = file->private_data;
tun_detach(tfile, true); - ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
return 0; }