Received-SPF: pass (google.com: domain of linux-bluetooth-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <CAO271mmuMDoqNdXUUuPpyz3VyuLWrZUr1K=Jry+H9mGEtz-Z4Q@mail.gmail.com>
 <CAO271m=vQsGwRvpe2tUUMuqB7r2z2cAut27U1LY6bQ_sHAk3NA@mail.gmail.com> <CABBYNZKs-JH_g2iUxStL5bRu-1z1TVzrS5pk2RyXUK8hiWYb7Q@mail.gmail.com>
In-Reply-To: <CABBYNZKs-JH_g2iUxStL5bRu-1z1TVzrS5pk2RyXUK8hiWYb7Q@mail.gmail.com>
From:   Sonny Sasaka <sonnysasaka@chromium.org>
Date:   Thu, 10 Feb 2022 16:02:01 -0800
Message-ID: <CAO271mnbrRxtEvMhc7GMaWY=BEKUzzv_CbN1j5WKf4NruKfJng@mail.gmail.com>
Subject: Re: Question about Trusted property
To:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc:     BlueZ <linux-bluetooth@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Luiz,

Thanks for the clarification. So my guess was right that it does not
have to do with bondedness. In that case, do you think it makes sense
to add a "Bonded" flag property to org.bluez.Device1? There are some
use case flows that pair with a peer device but do not actually bond,
and just with Paired property the UI can't know whether to show this
device as "Bonded" or not.

On Thu, Feb 10, 2022 at 1:30 PM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> Hi Sonny,
>
> On Thu, Feb 10, 2022 at 11:23 AM Sonny Sasaka <sonnysasaka@chromium.org> wrote:
> >
> > Dear maintainers,
> >
> > Friendly ping on this question. Does adding "Bonded" property to
> > org.bluez.Device1 make sense?
> >
> > On Fri, Feb 4, 2022 at 4:02 PM Sonny Sasaka <sonnysasaka@chromium.org> wrote:
> > >
> > > Hi Luiz/BlueZ maintainers,
> > >
> > > What is the purpose of the Trusted property on org.bluez.Device1
> > > interface? Does it mean whether the device is bonded? My experiment
> > > with BlueZ shows that sometimes a device with "Trusted" property set
> > > is not bonded (does not have pairing key stored) and also vice versa,
> > > so I am assuming that the Trusted property means something else. What
> > > is an example use case of the Trusted property?
> > >
> > > Eventually, what I am trying to achieve is for BlueZ clients to find
> > > out whether a device is Bonded or not. Using the Paired property is
> > > not very accurate because it is set to true during connection although
> > > the device is not bonded (pairing key does not persist after
> > > disconnection). For this purpose, I am about to propose adding
> > > "Bonded" property to org.bluez.Device1. Some use cases include when
> > > there is a temporary pairing with a peer device we don't want UI to
> > > show that the device is in the Bonded device list. What do you think
> > > about exposing the Bonded state via D-Bus? I will do the
> > > implementation if this idea makes sense.
> > >
> > > Thanks!
>
> Trusted primary use is to bypass agent authorization, so when set the
> agent will not have to authorize profile connections, and yes you can
> set a device to be Trusted even without having it paired since the
> bonding procedure refers to authentication rather than authorization
> which is what Trusted controls.
>
>
> --
> Luiz Augusto von Dentz