From: Linus Walleij <linus.walleij@linaro.org>
To: Jonathan Cameron <jic23@kernel.org>
Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
"Hartmut Knaack" <knaack.h@gmx.de>,
"Lars-Peter Clausen" <lars@metafoo.de>,
"Peter Meerwald-Stadler" <pmeerw@pmeerw.net>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>
Subject: Re: [PATCH 2/4] iio: magnetometer: ak8974: add_device_randomness(fw + serial)
Date: Sun, 20 Aug 2017 13:10:58 +0200 [thread overview]
Message-ID: <CACRpkdZECwAscLNs7irNzu73Rm7A4SYViRcmcwpuvHLpx11bKQ@mail.gmail.com> (raw)
In-Reply-To: <20170820112242.3008c3f8@archlinux>
On Sun, Aug 20, 2017 at 12:22 PM, Jonathan Cameron <jic23@kernel.org> wrote=
:
> On Thu, 17 Aug 2017 15:56:11 +0200
> Micha=C5=82 Miros=C5=82aw <mirq-linux@rere.qmqm.pl> wrote:
>> Signed-off-by: Micha=C5=82 Miros=C5=82aw <mirq-linux@rere.qmqm.pl>
>
> Hmm. I wondered about the firmware version as a source of randomness, but
> will leave it in here.
(...)
>> + add_device_randomness(&fw, sizeof(fw));
>
> The firmware version seems rather to guessable to really count as randomn=
ess.
> presumably it would constant for a particular batch of chips.
That is true, this should go, not for security reasons but because it doesn=
't
add much device-unique randomness.
Nothing we add with add_device_randomness() actually affects the entropy
pool trust, it is just icing making it - maybe - even more random, so addin=
g
256 zeroes is fine for the trust, just pointless and taking time for no goo=
d.
Yours,
Linus Walleij
next prev parent reply other threads:[~2017-08-20 11:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 13:56 [PATCH 0/4] iio: magnetometer: ak8974: support AMI306 Michał Mirosław
2017-08-17 13:56 ` [PATCH 1/4] iio: magnetometer: ak8974: support AMI306 variant Michał Mirosław
2017-08-20 10:19 ` Jonathan Cameron
2017-08-17 13:56 ` [PATCH 3/4] iio: magnetometer: ak8974: mark INT_CLEAR as precious Michał Mirosław
2017-08-17 13:56 ` [PATCH 2/4] iio: magnetometer: ak8974: add_device_randomness(fw + serial) Michał Mirosław
2017-08-20 10:22 ` Jonathan Cameron
2017-08-20 11:10 ` Linus Walleij [this message]
2017-08-20 14:18 ` Jonathan Cameron
2017-08-17 13:56 ` [PATCH 4/4] iio: magnetometer: ak8974: debug AMI306 calibration data Michał Mirosław
2017-08-20 10:25 ` Jonathan Cameron
2017-08-20 10:28 ` Jonathan Cameron
2017-08-20 14:40 ` Jonathan Cameron
2017-08-18 21:42 ` [PATCH 0/4] iio: magnetometer: ak8974: support AMI306 Linus Walleij
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