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

From: Matthew Garrett
Date: Tue Mar 19 2013 - 14:28:19 EST

On Tue, Mar 19, 2013 at 06:23:31PM +0000, James Bottomley wrote:

> The scheme we discussed, unless something radically changed, was to
> convey a temporary key pair via a mechanism to later verify the
> hybernate kernel on a resume. That only requires reboot safe knowledge
> of the public key. The private key can be conveyed in BS only (not NV),
> and should be consumed (as in deleted) by the OS when it receives it, so
> it wouldn't be exposed by this patch.

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.

Matthew Garrett | mjg59@xxxxxxxxxxxxx
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