4.14-stable review patch. If anyone has any objections, please let me know.
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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; }