Re: [PATCH] net: mac802154: fix WARNING in ieee802154_del_device

[Pavel Skripkin]

Hi!

On Mon, 2021-04-12 at 07:45 -0400, Alexander Aring wrote:
> Hi,
> 
> On Mon, 12 Apr 2021 at 06:58, Pavel Skripkin <paskripkin@xxxxxxxxx>
> wrote:
> > 
> > syzbot reported WARNING in ieee802154_del_device. The problem
> > was in uninitialized mutex. In case of NL802154_IFTYPE_MONITOR
> > mutex won't be initialized, but ieee802154_del_device() accessing
> > it.
> > 
> > Reported-by: syzbot+bf8b5834b7ec229487ce@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
> > ---
> >  net/mac802154/iface.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
> > index 1cf5ac09edcb..be8d2a02c882 100644
> > --- a/net/mac802154/iface.c
> > +++ b/net/mac802154/iface.c
> > @@ -599,6 +599,7 @@ ieee802154_setup_sdata(struct
> > ieee802154_sub_if_data *sdata,
> > 
> >                 break;
> >         case NL802154_IFTYPE_MONITOR:
> > +               mutex_init(&sdata->sec_mtx);
> >                 sdata->dev->needs_free_netdev = true;
> >                 sdata->dev->netdev_ops = &mac802154_monitor_ops;
> >                 wpan_dev->promiscuous_mode = true;
> 
> yes that will fix the issue, but will let the user notify that
> setting
> any security setting is supported by monitors which is not the case.
> There are patches around which should return -EOPNOTSUPP for
> monitors.
> However we might support it in future to let the kernel encrypt air
> frames, but this isn't supported yet and the user should be aware
> that
> it isn't.
> 

Thank you for your feedback. I am still not familiar with net internals
yet :) Next time I ll try to go deeper. Thanks!

> - Alex

With regards,
Pavel Skripkin