snp

Documentation

Overview

SNP

Attestation based on TPM and SEV-SNP attestation. The TPM is used to generate runtime measurements and signed by an attestation key that can be verified using the SEV-SNP attestation report.

Issuer

Generates a TPM attestation using an attestation key saved in the TPM. Additionally loads the SEV-SNP attestation report and AMD VCEK certificate chain, and adds them to the attestation document.

Validator

Verifies the attestation key used by first verifying the VCEK certificate chain and the SNP attestation report.

Glossary

This section explains abbreviations used in SNP implementation.

• Attestation Key (AK)

• AMD Root Key (ARK)

• AMD Signing Key (ASK)

• Versioned Chip Endorsement Key (VCEK)

  For more information see SNP WhitePaper

• Host (Hardware?) Compatibility Layer (HCL)

  No public information. Azure compute API has a field `isHostCompatibilityLayerVm`, with only a single sentence of documentation.

Index

• func GetIDKeyDigest(open vtpm.TPMOpenFunc) ([]byte, error)
• type HCLAkValidator
• type Issuer
  • func NewIssuer(log vtpm.AttestationLogger) *Issuer
• type Validator
  • func NewValidator(pcrs measurements.M, idKeyDigests idkeydigest.IDKeyDigests, ...) *Validator

Functions

func GetIDKeyDigest

func GetIDKeyDigest(open vtpm.TPMOpenFunc) ([]byte, error)

GetIDKeyDigest reads the idkeydigest from the snp report saved in the TPM's non-volatile memory.

Types

type HCLAkValidator

type HCLAkValidator interface {
	// contains filtered or unexported methods
}

HCLAkValidator validates an attestation key issued by the Host Compatibility Layer (HCL). The HCL is written by Azure, and sits between the Hypervisor and CVM OS. The HCL runs in the protected context of the CVM.

type Issuer

type Issuer struct {
	oid.AzureSEVSNP
	*vtpm.Issuer
}

Issuer for Azure TPM attestation.

func NewIssuer

func NewIssuer(log vtpm.AttestationLogger) *Issuer

NewIssuer initializes a new Azure Issuer.

type Validator

type Validator struct {
	oid.AzureSEVSNP
	*vtpm.Validator
}

Validator for Azure confidential VM attestation.

func NewValidator

func NewValidator(pcrs measurements.M, idKeyDigests idkeydigest.IDKeyDigests, enforceIDKeyDigest bool, log vtpm.AttestationLogger) *Validator

NewValidator initializes a new Azure validator with the provided PCR values.