Add support for EK Certificate chain from TPM NVRAM

[ematery]

Environment

• OS / version: NA
• Processor architecture: NA
• TPM Manufacturer: Intel firmware TPM 11th gen core, plus others
• Keylime version: NA

Description

The TCG EK specification allows for the storage of the EK Certificate chain in NVRAM. Specifically, the certificate chain should be stored in the memory range of 0x01c00100 to 0x01c001ff in DER format. It is important to note that Intel firmware for fTPM starting from the 11th generation Core processors has already implemented this functionality.

Additionally, this implementation necessitates an update to the Keylime server, as there is an existing issue related to this requirement (#1552).

Sources

TCG EK Credential Profile v2.5-R2, Chapter 2.2.1.5.2
Keylime Issue
Intel fTPM 11th gen core