Support portable measurement policies on bare metal - #83
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alexhulbert
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You should be good to add the RTMR0/MRTD and update the pinned attest commit to 12f1e29f6ea63ecc2f80f39c2c1f1172720bcf24. That will make RTMR0 and MRTD work.
I'll send a link to the latest tdx OVMF firmware that's on Ubuntu's repo. That seems like a good first firmware to pin. Going forward, we probably want to have a list of allowed MRTDs.
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Following Easy-TEE/attest#22 we want to allow portable measurement policies on bare metal.
Previously the
attestationcrate had a guard to disallow them as it was not fully implemented.This PR updates the attest crates and removes that guard. It also makes a change to the measurement policy record structure, as it must now explicitly specify an attestation type to remove ambiguity, as we can no longer assume portable measurements = GcpTdx.
Note for security: Unlike on GCP, we currently have no way to lookup the MRTD value to firmware on bare metal. So currently on bare metal, this will only match RTMR1 and 2, and accept any value for MRTD and RTMR0. So if the firmware is known, it is safer to use a 'standard' measurement policy and give the known MRTD value. If i understand correctly, Easy-TEE/attest#23 will address this.