From patchwork Fri Jan 11 08:50:41 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 211245 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id A57322C01E5 for ; Fri, 11 Jan 2013 19:59:41 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754769Ab3AKI7C (ORCPT ); Fri, 11 Jan 2013 03:59:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:28094 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260Ab3AKI7B (ORCPT ); Fri, 11 Jan 2013 03:59:01 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r0B8x0YB031972 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 11 Jan 2013 03:59:00 -0500 Received: from amd-6168-8-1.englab.nay.redhat.com (amd-6168-8-1.englab.nay.redhat.com [10.66.104.52]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r0B8wu8d007904; Fri, 11 Jan 2013 03:58:58 -0500 From: Jason Wang To: davem@davemloft.net, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jason Wang , Stefan Hajnoczi Subject: [PATCH 1/2] tuntap: forbid calling TUNSETIFF when detached Date: Fri, 11 Jan 2013 16:50:41 +0800 Message-Id: <1357894242-25020-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Michael points out that even after Stefan's fix the TUNSETIFF is still allowed to create a new tap device. This because we only check tfile->tun but the tfile->detached were introduced. Fix this by failing early in tun_set_iff() if the file is detached. After this fix, there's no need to do the check again in tun_set_iff(), so this patch removes it. Cc: Michael S. Tsirkin Cc: Stefan Hajnoczi Signed-off-by: Jason Wang --- drivers/net/tun.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 99b58d8..9a46d70 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -491,8 +491,6 @@ 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) @@ -1546,6 +1544,9 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) struct net_device *dev; int err; + if (rcu_dereference_protected(tfile->detached, lockdep_rtnl_is_held())) + return -EINVAL; + dev = __dev_get_by_name(net, ifr->ifr_name); if (dev) { if (ifr->ifr_flags & IFF_TUN_EXCL)