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tuntap: fix use after free during release

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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().

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>
This commit is contained in:
Jason Wang 2018-05-16 20:39:33 +08:00 committed by David S. Miller
parent fee8fb952d
commit 7063efd33b
1 changed files with 1 additions and 1 deletions
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2
drivers/net/tun.c
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@ -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;
}