Re: [RFC] Second attempt at kernel secure boot support

From: Alan Cox
Date: Wed Oct 31 2012 - 11:49:55 EST


> > is basically DMA-ing arbitrary data over the whole RAM. I am currently not
> > able to imagine a scenario how this could be made "secure" (without
> > storing private keys to sign the hibernation image on the machine itself
> > which, well, doesn't sound secure either).

That's what the TPM is for (in fact all of this stuff can be done
properly with a TPM while the 'secure' boot stuff can do little if any of
it.

>
> I have a patch that disables that. I imagine it will be included in the
> next submission of the patchset.
>
> You can find it here in the meantime:
>
> http://jwboyer.fedorapeople.org/pub/0001-hibernate-Disable-in-a-Secure-Boot-environment.patch

All this depends on your threat model. If I have physical access to
suspend/resume your machine then you already lost. If I don't have
physical access then I can't boot my unsigned OS to patch your S4 image
so it doesn't matter.

In fact the more I think about this the more it seems disabling hibernate
is basically farting in the wind.

Alan
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