From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH 3.8-rc] tuntap: refuse to re-attach to different tun_struct Date: Thu, 10 Jan 2013 17:25:45 +0800 Message-ID: <4517911.WDi5JC0yEs@jason-thinkpad-t430s> References: <1357804788-19976-1-git-send-email-stefanha@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: "David S. Miller" , "Michael S. Tsirkin" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Stefan Hajnoczi Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35778 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751201Ab3AJJZw (ORCPT ); Thu, 10 Jan 2013 04:25:52 -0500 In-Reply-To: <1357804788-19976-1-git-send-email-stefanha@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thursday, January 10, 2013 08:59:48 AM Stefan Hajnoczi wrote: > Multiqueue tun devices support detaching a tun_file from its tun_struct > and re-attaching at a later point in time. This allows users to disable > a specific queue temporarily. > > ioctl(TUNSETIFF) allows the user to specify the network interface to > attach by name. This means the user can attempt to attach to interface > "B" after detaching from interface "A". > > The driver is not designed to support this so check we are re-attaching > to the right tun_struct. Failure to do so may lead to oops. > > Signed-off-by: Stefan Hajnoczi > --- > This fix is for 3.8-rc. > > drivers/net/tun.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index fbd106e..cf6da6e 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -491,6 +491,8 @@ static int tun_attach(struct tun_struct *tun, struct > file *file) err = -EINVAL; > if (rcu_dereference_protected(tfile->tun, lockdep_rtnl_is_held())) > goto out; > + if (tfile->detached && tun != tfile->detached) > + goto out; > > err = -EBUSY; > if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) Thanks. Acked-by: Jason Wang