From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:40046 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030733AbeEXJ7P (ORCPT ); Thu, 24 May 2018 05:59:15 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrei Vagin , Jason Wang , "David S. Miller" Subject: [PATCH 4.16 012/161] tuntap: fix use after free during release Date: Thu, 24 May 2018 11:37:17 +0200 Message-Id: <20180524093019.883071948@linuxfoundation.org> In-Reply-To: <20180524093018.331893860@linuxfoundation.org> References: <20180524093018.331893860@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ 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 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: Greg Kroah-Hartman --- 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; }