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Subject: Re: [PATCH] net: mac802154: fix WARNING in ieee802154_del_device
From:   Pavel Skripkin <paskripkin@gmail.com>
To:     Alexander Aring <alex.aring@gmail.com>
Cc:     Stefan Schmidt <stefan@datenfreihafen.org>,
        "David S. Miller" <davem@davemloft.net>,
        linux-wpan - ML <linux-wpan@vger.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>,
        kernel list <linux-kernel@vger.kernel.org>,
        syzbot+bf8b5834b7ec229487ce@syzkaller.appspotmail.com
Date:   Mon, 12 Apr 2021 19:41:58 +0300
In-Reply-To: <CAB_54W7R6ZmMQQPscc04PhJsGu_uoaVqVx=PAiLrqb4nZqTWzw@mail.gmail.com>
References: <20210412105851.24809-1-paskripkin@gmail.com>
         <CAB_54W7R6ZmMQQPscc04PhJsGu_uoaVqVx=PAiLrqb4nZqTWzw@mail.gmail.com>
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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@gmail.com>
> 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@syzkaller.appspotmail.com
> > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> > ---
> >  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