| From 7063efd33bb15abc0160347f89eb5aba6b7d000e Mon Sep 17 00:00:00 2001 |
| From: Jason Wang <jasowang@redhat.com> |
| Date: Wed, 16 May 2018 20:39:33 +0800 |
| Subject: tuntap: fix use after free during release |
| |
| From: Jason Wang <jasowang@redhat.com> |
| |
| 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@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: Zubin Mithra <zsm@chromium.org> |
| 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 |
| @@ -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; |
| } |
