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Subject: Re: [Bluez PATCH v2] btmgmt: Fix enable adding irk when turining
 privacy on
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <CABBYNZ+kQn-H7QSEieWdP=oTjb+m4NBP03i2VoUy5pcfx0UD8A@mail.gmail.com>
Date:   Thu, 13 May 2021 17:20:48 +0200
Cc:     Sathish Narasimman <sathish.narasimman@intel.com>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        Chethan T N <chethan.tumkur.narayan@intel.com>,
        "Srivatsa, Ravishankar" <ravishankar.srivatsa@intel.com>
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References: <20210504111454.29697-1-sathish.narasimman@intel.com>
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 <CE33C971-7C6F-4D1E-9031-77FE07200038@holtmann.org>
 <CABBYNZ+kQn-H7QSEieWdP=oTjb+m4NBP03i2VoUy5pcfx0UD8A@mail.gmail.com>
To:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Precedence: bulk

Hi Luiz,

>>>> Unable to add the IRK in btmgmt when need to be updated. The option is
>>>> enabled now.
>>>> 
>>>> Signed-off-by: Sathish Narasimman <sathish.narasimman@intel.com>
>>>> ---
>>>> tools/btmgmt.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>> 
>>>> diff --git a/tools/btmgmt.c b/tools/btmgmt.c
>>>> index 02fec1dca184..bf3b460d0f04 100644
>>>> --- a/tools/btmgmt.c
>>>> +++ b/tools/btmgmt.c
>>>> @@ -5277,7 +5277,7 @@ static const struct bt_shell_menu main_menu = {
>>>>       cmd_advertising,                "Toggle LE advertising",        },
>>>>       { "bredr",              "<on/off>",
>>>>               cmd_bredr,              "Toggle BR/EDR support",        },
>>>> -       { "privacy",            "<on/off>",
>>>> +       { "privacy",            "<on/off> [irk]",
>>>>               cmd_privacy,            "Toggle privacy support"        },
>>> 
>>> I wonder why you didn't incorporate in the first parameter though
>>> given that things like privacy off [irk] makes no send, or perhaps
>>> have a dedicated command for setting the irk so it would persist
>>> between privacy on/off.
>> 
>> that is not how the kernel API works. If you want to enable Privacy, you need to also provide the IRK. We just simplified the tool to use /dev/urandom in case it is not provided.
> 
> Just to be clear I was suggesting to use a dedicated command for setting an irk:
> 
>> irk <value>
> 
> That way it is persisted, that way the tool remembers what was the
> last set irk in case privacy needs to be toggled for some reason.

but btmgmt has no storage facility. It can’t remember its own name if its life depended on it ;)

Regards

Marcel