4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Wang <jasowang@xxxxxxxxxx>
[ Upstream commit 7063efd33bb15abc0160347f89eb5aba6b7d000e ]
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@xxxxxxxxxxxxx>
Acked-by: Andrei Vagin <avagin@xxxxxxxxxxxxx>
Fixes: b196d88aba8a ("tun: fix use after free for ptr_ring")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/tun.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -728,6 +728,7 @@ static void __tun_detach(struct tun_file
}
if (tun)
xdp_rxq_info_unreg(&tfile->xdp_rxq);
+ ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
sock_put(&tfile->sk);
}
}
@@ -3157,7 +3158,6 @@ static int tun_chr_close(struct inode *i
struct tun_file *tfile = file->private_data;
tun_detach(tfile, true);
- ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
return 0;
}
