linux-kernel - Re: [PATCH] x86/efi: pull NV+BS variables out before we exit boot services

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Message-ID: <20130319182810.GA13003@srcf.ucam.org>
Date:	Tue, 19 Mar 2013 18:28:10 +0000
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	James Bottomley <James.Bottomley@...senPartnership.com>
Cc:	linux-efi@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/efi: pull NV+BS variables out before we exit boot
 services

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@...f.ucam.org
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