From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752537AbeEPMjl (ORCPT ); Wed, 16 May 2018 08:39:41 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:35610 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752205AbeEPMjj (ORCPT ); Wed, 16 May 2018 08:39:39 -0400 From: Jason Wang To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: xiyou.wangcong@gmail.com, avagin@virtuozzo.com, mst@redhat.com, Jason Wang Subject: [PATCH net] tuntap: fix use after free during release Date: Wed, 16 May 2018 20:39:33 +0800 Message-Id: <1526474373-16685-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9fbbb32..d45ac37 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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; } -- 2.7.4