I searched TCG and it’s not obvious to me. Is there a TCG standard on DRTM?

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David Li

Cloudshield Technologies

SAIC

Tel. 408-212-9265 (work)

        650-224-3891 (cell)

From: Cihula, Joseph [mailto:joseph.cihula@intel.com]
Sent: Tuesday, September 27, 2011 12:00 AM
To: Li, David; trusted-computing@lists.fedorahosted.org
Subject: RE: TPM measurement during a PXEboot

You could try a dynamic root of trust, which can be initiated from a PXE-booted image and won’t depend on whether the PXE ROM measures it or not.

Joe

From: trusted-computing-bounces@lists.fedorahosted.org [mailto:trusted-computing-bounces@lists.fedorahosted.org] On Behalf Of Li, David
Sent: Monday, September 26, 2011 5:08 PM
To: trusted-computing@lists.fedorahosted.org
Subject: [Trusted-computing] TPM measurement during a PXEboot

I know the spec (TCG EFI Platform Spec v1.2) doesn’t explicitly mention what to do in a PXEBoot regarding kernel image TPM measurement.  Sounds like this should fall into the general category of kernel measurement into PCR4 and 5.  Now in my case, this is a gray area in reality. Typically PXEboot is handed by the PXE ROM in a NIC card and not by the motherboard BIOS.  What if the main BIOS does its job but has to stop at the PXE ROM while the PXE ROM doesn’t measure the loader and kernel image at all?  In other words, if my chain of trust stops (or breaks) at the PXE ROM, is there any other way to solve this problem?

Thanks.

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David Li

Cloudshield Technologies

SAIC