constellation/internal/attestation/azure/tdx/validator.go
Daniel Weiße daaa7755a7
cli: enable JSON output for constellation verify on Azure TDX (#3164)
* Remove formatter factory
* Enable `constellation verify` with JSON output for Azure TDX

---------

Signed-off-by: Daniel Weiße <dw@edgeless.systems>
2024-06-12 13:18:27 +02:00

125 lines
3.2 KiB
Go

/*
Copyright (c) Edgeless Systems GmbH
SPDX-License-Identifier: AGPL-3.0-only
*/
package tdx
import (
"context"
"crypto"
"crypto/x509"
"encoding/json"
"fmt"
"github.com/edgelesssys/constellation/v2/internal/attestation"
"github.com/edgelesssys/constellation/v2/internal/attestation/azure"
"github.com/edgelesssys/constellation/v2/internal/attestation/variant"
"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
"github.com/edgelesssys/constellation/v2/internal/config"
"github.com/google/go-tdx-guest/abi"
"github.com/google/go-tdx-guest/proto/tdx"
"github.com/google/go-tdx-guest/validate"
"github.com/google/go-tdx-guest/verify"
"github.com/google/go-tdx-guest/verify/trust"
"github.com/google/go-tpm-tools/proto/attest"
"github.com/google/go-tpm/legacy/tpm2"
)
// Validator for Azure confidential VM attestation using TDX.
type Validator struct {
variant.AzureTDX
*vtpm.Validator
cfg *config.AzureTDX
getter trust.HTTPSGetter
hclValidator hclAkValidator
}
// NewValidator returns a new Validator for Azure confidential VM attestation using TDX.
func NewValidator(cfg *config.AzureTDX, log attestation.Logger) *Validator {
v := &Validator{
cfg: cfg,
getter: trust.DefaultHTTPSGetter(),
hclValidator: &azure.HCLAkValidator{},
}
v.Validator = vtpm.NewValidator(
cfg.Measurements,
v.getTrustedTPMKey,
func(vtpm.AttestationDocument, *attest.MachineState) error {
return nil
},
log,
)
return v
}
func (v *Validator) getTrustedTPMKey(_ context.Context, attDoc vtpm.AttestationDocument, _ []byte) (crypto.PublicKey, error) {
var instanceInfo InstanceInfo
if err := json.Unmarshal(attDoc.InstanceInfo, &instanceInfo); err != nil {
return nil, err
}
quotePb, err := abi.QuoteToProto(instanceInfo.AttestationReport)
if err != nil {
return nil, err
}
quote, ok := quotePb.(*tdx.QuoteV4)
if !ok {
return nil, fmt.Errorf("unexpected quote type: %T", quote)
}
if err := v.validateQuote(quote); err != nil {
return nil, err
}
// Decode the public area of the attestation key and validate its trustworthiness.
pubArea, err := tpm2.DecodePublic(attDoc.Attestation.AkPub)
if err != nil {
return nil, err
}
if err = v.hclValidator.Validate(instanceInfo.RuntimeData, quote.TdQuoteBody.ReportData, pubArea.RSAParameters); err != nil {
return nil, fmt.Errorf("validating HCLAkPub: %w", err)
}
return pubArea.Key()
}
func (v *Validator) validateQuote(tdxQuote *tdx.QuoteV4) error {
roots := x509.NewCertPool()
roots.AddCert((*x509.Certificate)(&v.cfg.IntelRootKey))
if err := verify.TdxQuote(tdxQuote, &verify.Options{
CheckRevocations: true,
GetCollateral: true,
TrustedRoots: roots,
Getter: v.getter,
}); err != nil {
return err
}
if err := validate.TdxQuote(tdxQuote, &validate.Options{
HeaderOptions: validate.HeaderOptions{
MinimumQeSvn: v.cfg.QESVN,
MinimumPceSvn: v.cfg.PCESVN,
QeVendorID: v.cfg.QEVendorID,
},
TdQuoteBodyOptions: validate.TdQuoteBodyOptions{
MinimumTeeTcbSvn: v.cfg.TEETCBSVN,
MrSeam: v.cfg.MRSeam,
Xfam: v.cfg.XFAM,
},
}); err != nil {
return err
}
return nil
}
type hclAkValidator interface {
Validate(runtimeDataRaw []byte, reportData []byte, rsaParameters *tpm2.RSAParams) error
}