Re: [PATCH] x86/efi: pull NV+BS variables out before we exit bootservices

[Matthew Garrett]

On Tue, Mar 19, 2013 at 06:40:56PM +0000, James Bottomley wrote:
> On Tue, 2013-03-19 at 18:28 +0000, Matthew Garrett wrote:
> > It requires the key to survive the system being entirely powered down, 
> > which means it needs to be BS+NV. It shouldn't be possible for userspace 
> > to access this key.
> 
> It requires the *public* key to survive power down, certainly.  The
> private key can be thrown away once the hibernate image is signed.  I
> think the scheme can be constructed so the private key is never in NV
> storage ... that also makes it more secure against tampering.

Well, that somewhat complicates implementation - we'd be encrypting the 
entire contents of memory except for the key that we're using to encrypt 
memory. Keeping the public key away from userspace avoids having to care 
about that.

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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