4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang <jasowang@xxxxxxxxxx> commit 7063efd33bb15abc0160347f89eb5aba6b7d000e upstream. 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(). Backport Note :- Upstream commit moves the ptr_ring_cleanup call from tun_chr_close to __tun_detach. Upstream applied that patch after replacing skb_array with ptr_ring. This patch moves the skb_array_cleanup call from tun_chr_close to __tun_detach. Reported-by: Andrei Vagin <avagin@xxxxxxxxxxxxx> Acked-by: Andrei Vagin <avagin@xxxxxxxxxxxxx> Fixes: b196d88aba8a ("tun: fix use after free for ptr_ring") Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Zubin Mithra <zsm@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -575,6 +575,7 @@ static void __tun_detach(struct tun_file tun->dev->reg_state == NETREG_REGISTERED) unregister_netdevice(tun->dev); } + skb_array_cleanup(&tfile->tx_array); sock_put(&tfile->sk); } } @@ -2646,7 +2647,6 @@ static int tun_chr_close(struct inode *i struct tun_file *tfile = file->private_data; tun_detach(tfile, true); - skb_array_cleanup(&tfile->tx_array); return 0; }