From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang 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> Cc: Jason Wang , Stefan Hajnoczi To: davem@davemloft.net, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: 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) -- 1.7.1