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tuntap: fix use after free during release 

commit 7063efd33b upstream.

After commit b196d88aba ("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: b196d88aba ("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>
pull/10/head
Jason Wang 2018-05-16 20:39:33 +08:00 committed by Greg Kroah-Hartman
parent ab75811f71
commit daf0ca743b
1 changed files with 1 additions and 1 deletions
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2
drivers/net/tun.c
View File

@ -575,6 +575,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
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 *inode, struct file *file)
struct tun_file *tfile = file->private_data;
tun_detach(tfile, true);
skb_array_cleanup(&tfile->tx_array);
return 0;
}