Re: A _good_ and valid use for TPM

[Robert Millan <rmh@aybabtu.com>]

On Sun, Feb 22, 2009 at 03:14:07AM +0200, Alex Besogonov wrote:
> Jan Alsenz wrote:
>>>> Yeah, but an attacker could patch that out too.
>>> Not if we first measure the MBR. It can be done without any
>>> TPM-specific code in the MBR if I'm not very mistaken.
>> Could you elaborate on that?
>> E.g. where do you measure the MBR from?
> MBR is automatically measured by the TPM module, it requires no  
> intervention from GRUB.

Well, that is true, but for GRUB to measure all of its own stages
it gets quite complicated.  Overall, from a technical POV it looks
like a lousy approach.  It makes a lot more sense to simply have the
firmware load GRUB as an executable image and measure that IMO.

You can do that easily when you're in a legacy-free environment.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."