| Message ID | 1526474373-16685-1-git-send-email-jasowang@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] tuntap: fix use after free during release | expand |
From: Jason Wang <jasowang@redhat.com> Date: Wed, 16 May 2018 20:39:33 +0800 > 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> Applied and queued up for -stable.
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9fbbb32..d45ac37 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -729,6 +729,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean) } if (tun) xdp_rxq_info_unreg(&tfile->xdp_rxq); + ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free); sock_put(&tfile->sk); } } @@ -3245,7 +3246,6 @@ static int tun_chr_close(struct inode *inode, struct file *file) struct tun_file *tfile = file->private_data; tun_detach(tfile, true); - ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free); return 0; }
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> --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)