mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-12-27 16:39:38 -05:00
112 lines
4.9 KiB
Go
112 lines
4.9 KiB
Go
/*
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Copyright (c) Edgeless Systems GmbH
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SPDX-License-Identifier: AGPL-3.0-only
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*/
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package trustedlaunch
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import (
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"crypto"
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"crypto/rsa"
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"crypto/x509"
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"encoding/json"
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"errors"
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"fmt"
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"github.com/edgelesssys/constellation/v2/internal/attestation/measurements"
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"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
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certutil "github.com/edgelesssys/constellation/v2/internal/crypto"
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"github.com/edgelesssys/constellation/v2/internal/oid"
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"github.com/google/go-tpm-tools/proto/attest"
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"github.com/google/go-tpm/tpm2"
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)
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// ameRoot is the AME root CA certificate used to sign Azure's AME Infra CA certificates.
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// The certificate can be found at http://crl.microsoft.com/pkiinfra/certs/AMERoot_ameroot.crt.
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var ameRoot = mustParseX509("-----BEGIN CERTIFICATE-----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\nyTra6P0Kvo6xz4KaVm8F7VDzUP+heAAhPAs=\n-----END CERTIFICATE-----\n")
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// Validator for Azure trusted launch VM attestation.
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type Validator struct {
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oid.AzureTrustedLaunch
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*vtpm.Validator
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roots *x509.CertPool
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}
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// NewValidator initializes a new Azure validator with the provided PCR values.
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func NewValidator(pcrs measurements.M, log vtpm.AttestationLogger) *Validator {
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rootPool := x509.NewCertPool()
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rootPool.AddCert(ameRoot)
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v := &Validator{roots: rootPool}
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v.Validator = vtpm.NewValidator(
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pcrs,
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v.verifyAttestationKey,
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validateVM,
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log,
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)
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return v
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}
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// verifyAttestationKey establishes trust in an attestation key.
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// It does so by verifying the certificate chain of the attestation key certificate.
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func (v *Validator) verifyAttestationKey(akPub, instanceInfo []byte) (crypto.PublicKey, error) {
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pubArea, err := tpm2.DecodePublic(akPub)
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if err != nil {
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return nil, fmt.Errorf("decoding attestation key public area: %w", err)
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}
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var akSigner akSigner
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if err := json.Unmarshal(instanceInfo, &akSigner); err != nil {
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return nil, fmt.Errorf("unmarshaling attestation key signer info: %w", err)
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}
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akCert, err := x509.ParseCertificate(akSigner.AkCert)
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if err != nil {
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return nil, fmt.Errorf("parsing attestation key certificate: %w", err)
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}
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akCertCA, err := x509.ParseCertificate(akSigner.CA)
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if err != nil {
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return nil, fmt.Errorf("parsing attestation key CA certificate: %w", err)
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}
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intermediates := x509.NewCertPool()
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intermediates.AddCert(akCertCA)
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if _, err := akCert.Verify(x509.VerifyOptions{
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Roots: v.roots,
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Intermediates: intermediates,
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KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
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}); err != nil {
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return nil, fmt.Errorf("verifying attestation key certificate: %w", err)
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}
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pubKey, err := pubArea.Key()
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if err != nil {
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return nil, fmt.Errorf("getting public key: %w", err)
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}
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pubKeyRSA, ok := pubKey.(*rsa.PublicKey)
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if !ok {
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return nil, errors.New("attestation key is not an RSA key")
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}
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if !pubKeyRSA.Equal(akCert.PublicKey) {
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return nil, errors.New("certificate public key does not match attestation key")
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}
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return pubKeyRSA, nil
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}
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// validateVM returns nil.
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func validateVM(vtpm.AttestationDocument, *attest.MachineState) error {
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return nil
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}
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func mustParseX509(pem string) *x509.Certificate {
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cert, err := certutil.PemToX509Cert([]byte(pem))
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if err != nil {
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panic(err)
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}
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return cert
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}
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