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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Thu, 10 Feb 2022 13:30:10 -0800
Message-ID: <CABBYNZKs-JH_g2iUxStL5bRu-1z1TVzrS5pk2RyXUK8hiWYb7Q@mail.gmail.com>
Subject: Re: Question about Trusted property
To:     Sonny Sasaka <sonnysasaka@chromium.org>
Cc:     BlueZ <linux-bluetooth@vger.kernel.org>
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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