Re: [PATCH] nvmem: sunxi-sid: SID content is not a valid source of randomness
From: Jean-Francois Moine
Date: Tue Oct 25 2016 - 03:16:54 EST
On Tue, 25 Oct 2016 07:38:55 +0200
LABBE Corentin <clabbe.montjoie@xxxxxxxxx> wrote:
> > On Sat, Oct 22, 2016 at 03:53:28PM +0200, Corentin Labbe wrote:
> > > Since SID's content is constant over reboot,
> >
> > That's not true, at least not across all the Allwinner SoCs, and
> > especially not on the A10 and A20 that this driver supports.
> >
>
> On my cubieboard2 (A20)
> hexdump -C /sys/devices/platform/soc\@01c00000/1c23800.eeprom/sunxi-sid0/nvmem
> 00000000 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000100 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000200
> cubiedev ~ # reboot
> cubiedev ~ # hexdump -C /sys/devices/platform/soc\@01c00000/1c23800.eeprom/sunxi-sid0/nvmem
> 00000000 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000100 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000200
>
> So clearly for me its constant.
Even after power off/power on?
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