From: Jason Wang Date: Wed, 16 May 2018 12:39:33 +0000 (+0800) Subject: tuntap: fix use after free during release X-Git-Tag: v4.14.71~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=daf0ca743b28050664c7bd03b6fb46a95d94d248;p=platform%2Fkernel%2Flinux-exynos.git tuntap: fix use after free during release 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 Acked-by: Andrei Vagin Fixes: b196d88aba8a ("tun: fix use after free for ptr_ring") Signed-off-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Zubin Mithra Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 87a989be1cef..e0baea2dfd3c 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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; }