constellation/coordinator/attestation/azure/validator.go
Daniel Weiße 956ced6e3d Add qemu vTPM issuer and validator
Signed-off-by: Daniel Weiße <dw@edgeless.systems>
2022-04-28 14:46:24 +02:00

49 lines
1.3 KiB
Go

package azure
import (
"crypto"
"github.com/edgelesssys/constellation/coordinator/attestation/vtpm"
"github.com/edgelesssys/constellation/coordinator/oid"
"github.com/google/go-tpm/tpm2"
)
// Validator for Azure confidential VM attestation.
type Validator struct {
oid.Azure
*vtpm.Validator
}
// NewValidator initializes a new Azure validator with the provided PCR values.
func NewValidator(pcrs map[uint32][]byte) *Validator {
return &Validator{
Validator: vtpm.NewValidator(
pcrs,
trustedKeyFromSNP,
validateAzureCVM,
vtpm.VerifyPKCS1v15,
),
}
}
// trustedKeyFromSNP establishes trust in the given public key.
// It does so by verifying the SNP attestation statement in instanceInfo.
//
// As long as we are using regular VMs on Azure this is a stub, only returning the given key.
func trustedKeyFromSNP(akPub, instanceInfo []byte) (crypto.PublicKey, error) {
// TODO: convert this to SEV-SNP attestation verification
pubArea, err := tpm2.DecodePublic(akPub)
if err != nil {
return nil, err
}
return pubArea.Key()
}
// validateAzureCVM validates Azure CVM capabilities.
//
// This might stay a stub, since SEV-SNP attestation is already verified in trustedKeyFromSNP().
func validateAzureCVM(attestation vtpm.AttestationDocument) error {
// TODO: implement this for CVMs
return nil
}