On Thu, Jan 10, 2013 at 10:08:03PM +0800, Jason Wang wrote: > On 01/10/2013 07:31 PM, Michael S. Tsirkin wrote: > > At the moment, we check owner when we enable queue in tun. > > This seems redundant and will break some valid uses > > where fd is passed around: I think TUNSETOWNER is there > > to prevent others from attaching to a persistent device not > > owned by them. Here the fd is already attached, > > enabling/disabling queue is more like read/write. > > It also change the number of queues of the tuntap, maybe we should limit > this.
Number of active queues? Why does it matter? Max number of queues is already limited by SETIFF. > Note that if management layer does not call TUNSETOWNER, the check > is just a nop. So if management layer want to limit the behavior, it's > its duty to do this correctly. The point is that management limits tun to allow SETIFF from libvirt only, then passes the fds to qemu. > > Signed-off-by: Michael S. Tsirkin <[email protected]> > > > > --- > > > > Note: this is unrelated to Stefan's bugfix. > > > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > > index fbd106e..78e3225 100644 > > --- a/drivers/net/tun.c > > +++ b/drivers/net/tun.c > > @@ -1789,10 +1792,8 @@ static int tun_set_queue(struct file *file, struct > > ifreq *ifr) > > tun = tfile->detached; > > if (!tun) > > ret = -EINVAL; > > - else if (tun_not_capable(tun)) > > - ret = -EPERM; > > else > > ret = tun_attach(tun, file); > > } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { > > tun = rcu_dereference_protected(tfile->tun, > > lockdep_rtnl_is_held()); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
