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From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date: Tue, 29 May 2018 13:14:01 +0300
Message-ID: <CABBYNZ+xKYR2xEznvPoRBteb9nbDTGLvyxEG77NZ1-odbFjyCQ@mail.gmail.com>
Subject: Re: [PATCH BlueZ 2/2] gatt: Don't require prepare write authorization
 for trusted devices
To: =?UTF-8?Q?Grzegorz_Ko=C5=82odziejczyk?=
        <grzegorz.kolodziejczyk@codecoup.pl>
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Hi Grzegorz,

On Tue, May 29, 2018 at 1:05 PM, Grzegorz Ko=C5=82odziejczyk
<grzegorz.kolodziejczyk@codecoup.pl> wrote:
> Hi Luiz,
>
>
> wt., 29 maj 2018 o 11:39 Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> napisa=C5=82(a):
>
>> Hi Grzegorz,
>
>> On Tue, May 29, 2018 at 11:32 AM, Grzegorz Kolodziejczyk
>> <grzegorz.kolodziejczyk@codecoup.pl> wrote:
>> > This patch adds possibility to ommit prepare write authorization
>> > request from trusted devices.
>> > ---
>> >  src/gatt-database.c | 6 ++++--
>> >  1 file changed, 4 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/src/gatt-database.c b/src/gatt-database.c
>> > index 22c78e840..99c8ea231 100644
>> > --- a/src/gatt-database.c
>> > +++ b/src/gatt-database.c
>> > @@ -2569,7 +2569,8 @@ static void desc_write_cb(struct
> gatt_db_attribute *attrib,
>> >         }
>> >
>> >         if (opcode =3D=3D BT_ATT_OP_PREP_WRITE_REQ) {
>> > -               if (!desc->prep_authorized &&
> desc->req_prep_authorization)
>> > +               if (!device_is_trusted(device) &&
> !desc->prep_authorized &&
>> > +
> desc->req_prep_authorization)
>> >                         send_write(device, attrib, desc->proxy,
>> >                                         desc->pending_writes, id,
> value, len,
>> >                                         offset,
> bt_att_get_link_type(att),
>> > @@ -2672,7 +2673,8 @@ static void chrc_write_cb(struct
> gatt_db_attribute *attrib,
>> >                 queue =3D NULL;
>> >
>> >         if (opcode =3D=3D BT_ATT_OP_PREP_WRITE_REQ) {
>> > -               if (!chrc->prep_authorized &&
> chrc->req_prep_authorization)
>> > +               if (!device_is_trusted(device) &&
> !chrc->prep_authorized &&
>> > +
> chrc->req_prep_authorization)
>> >                         send_write(device, attrib, chrc->proxy, queue,
>> >                                         id, value, len, offset,
>> >                                         bt_att_get_link_type(att),
> true, true);
>> > --
>> > 2.13.6
>
>> I guess I can ignore the first patch and just apply this one, or do
>> you still have any use for checking the trusted flag on the client
>> side?
>
> Yes, I have use for checking the trusted flag on client side.
>
> For example:
> - Read/write,
> - Long read, long write,
> - Execute write

Right, so those are to prevent the client to show any prompt, got it now.

> In all those cases user will be bothered with authorization request if
> trusted won't be checked.
>
> This patch 2/2 reduce redundant authorization request for prepare writes
> only since we know that device is trusted on daemon side. In other cases
> operation is authorized on client side, so I think there is no other plac=
e
> where we can check if device is trusted.
>
>> --
>> Luiz Augusto von Dentz
>
> Regards,
> Grzegorz



--=20
Luiz Augusto von Dentz