From 6e331f4c83021e4de2a2fc4981574b5d5b16c425 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 9 Jan 2013 21:59:48 +0000 Subject: [PATCH] tuntap: refuse to re-attach to different tun_struct 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 Acked-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index fbd106edbe59..cf6da6efc71a 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) -- 2.20.1