attestation: create issuer based on kernel cmd line (#1355)

Signed-off-by: Daniel Weiße <dw@edgeless.systems>

bootstrapper/cmd/bootstrapper/main.go

@@ -18,12 +18,7 @@ import (
 	"github.com/edgelesssys/constellation/v2/bootstrapper/internal/kubernetes/k8sapi"
 	"github.com/edgelesssys/constellation/v2/bootstrapper/internal/kubernetes/kubewaiter"
 	"github.com/edgelesssys/constellation/v2/bootstrapper/internal/logging"
-	"github.com/edgelesssys/constellation/v2/internal/atls"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/aws"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/snp"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/trustedlaunch"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/gcp"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/qemu"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/choose"
 	"github.com/edgelesssys/constellation/v2/internal/attestation/simulator"
 	"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
 	awscloud "github.com/edgelesssys/constellation/v2/internal/cloud/aws"
@@ -41,7 +36,7 @@ import (
 )
 
 const (
-	// ConstellationCSP is the environment variable stating which Cloud Service Provider Constellation is running on.
+	// constellationCSP is the environment variable stating which Cloud Service Provider Constellation is running on.
 	constellationCSP = "CONSTEL_CSP"
 )
 
@@ -66,7 +61,6 @@ func main() {
 	var clusterInitJoiner clusterInitJoiner
 	var metadataAPI metadataAPI
 	var cloudLogger logging.CloudLogger
-	var issuer atls.Issuer
 	var openTPM vtpm.TPMOpenFunc
 	var fs afero.Fs
 
@@ -75,6 +69,15 @@ func main() {
 		log.With(zap.Error(err)).Fatalf("Helm client could not be initialized")
 	}
 
+	attestVariant, err := oid.FromString(os.Getenv(constants.AttestationVariant))
+	if err != nil {
+		log.With(zap.Error(err)).Fatalf("Failed to parse attestation variant")
+	}
+	issuer, err := choose.Issuer(attestVariant, log)
+	if err != nil {
+		log.With(zap.Error(err)).Fatalf("Failed to select issuer")
+	}
+
 	switch cloudprovider.FromString(os.Getenv(constellationCSP)) {
 	case cloudprovider.AWS:
 		measurements, err := vtpm.GetSelectedMeasurements(vtpm.OpenVTPM, vtpm.AWSPCRSelection)
@@ -82,8 +85,6 @@ func main() {
 			log.With(zap.Error(err)).Fatalf("Failed to get selected PCRs")
 		}
 
-		issuer = aws.NewIssuer(log)
-
 		metadata, err := awscloud.New(ctx)
 		if err != nil {
 			log.With(zap.Error(err)).Fatalf("Failed to set up AWS metadata API")
@@ -108,8 +109,6 @@ func main() {
 			log.With(zap.Error(err)).Fatalf("Failed to get selected PCRs")
 		}
 
-		issuer = gcp.NewIssuer(log)
-
 		metadata, err := gcpcloud.New(ctx)
 		if err != nil {
 			log.With(zap.Error(err)).Fatalf("Failed to create GCP metadata client")
@@ -136,13 +135,6 @@ func main() {
 			log.With(zap.Error(err)).Fatalf("Failed to get selected PCRs")
 		}
 
-		if _, err := snp.GetIDKeyDigest(vtpm.OpenVTPM); err == nil {
-			issuer = snp.NewIssuer(log)
-		} else {
-			// assume we are running in a trusted-launch VM
-			issuer = trustedlaunch.NewIssuer(log)
-		}
-
 		metadata, err := azurecloud.New(ctx)
 		if err != nil {
 			log.With(zap.Error(err)).Fatalf("Failed to create Azure metadata client")
@@ -166,8 +158,6 @@ func main() {
 			log.With(zap.Error(err)).Fatalf("Failed to get selected PCRs")
 		}
 
-		issuer = qemu.NewIssuer(log)
-
 		cloudLogger = qemucloud.NewLogger()
 		metadata := qemucloud.New()
 		clusterInitJoiner = kubernetes.New(
@@ -179,7 +169,6 @@ func main() {
 		openTPM = vtpm.OpenVTPM
 		fs = afero.NewOsFs()
 	default:
-		issuer = atls.NewFakeIssuer(oid.Dummy{})
 		clusterInitJoiner = &clusterFake{}
 		metadataAPI = &providerMetadataFake{}
 		cloudLogger = &logging.NopLogger{}

disk-mapper/cmd/main.go

@@ -14,17 +14,14 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"path/filepath"
 
 	"github.com/edgelesssys/constellation/v2/disk-mapper/internal/mapper"
 	"github.com/edgelesssys/constellation/v2/disk-mapper/internal/recoveryserver"
 	"github.com/edgelesssys/constellation/v2/disk-mapper/internal/rejoinclient"
 	"github.com/edgelesssys/constellation/v2/disk-mapper/internal/setup"
-	"github.com/edgelesssys/constellation/v2/internal/atls"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/aws"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/azure"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/gcp"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/qemu"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/choose"
 	"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
 	awscloud "github.com/edgelesssys/constellation/v2/internal/cloud/aws"
 	azurecloud "github.com/edgelesssys/constellation/v2/internal/cloud/azure"
@@ -37,6 +34,7 @@ import (
 	"github.com/edgelesssys/constellation/v2/internal/grpc/dialer"
 	kmssetup "github.com/edgelesssys/constellation/v2/internal/kms/setup"
 	"github.com/edgelesssys/constellation/v2/internal/logger"
+	"github.com/edgelesssys/constellation/v2/internal/oid"
 	"github.com/edgelesssys/constellation/v2/internal/role"
 	tpmClient "github.com/google/go-tpm-tools/client"
 	"github.com/google/go-tpm/tpm2"
@@ -61,10 +59,18 @@ func main() {
 	log.With(zap.String("version", constants.VersionInfo()), zap.String("cloudProvider", *csp)).
 		Infof("Starting disk-mapper")
 
-	// set up metadata API and quote issuer for aTLS connections
-	var err error
+	// set up quote issuer for aTLS connections
+	attestVariant, err := oid.FromString(os.Getenv(constants.AttestationVariant))
+	if err != nil {
+		log.With(zap.Error(err)).Fatalf("Failed to parse attestation variant")
+	}
+	issuer, err := choose.Issuer(attestVariant, log)
+	if err != nil {
+		log.With(zap.Error(err)).Fatalf("Failed to select issuer")
+	}
+
+	// set up metadata API
 	var diskPath string
-	var issuer atls.Issuer
 	var metadataClient setup.MetadataAPI
 	switch cloudprovider.FromString(*csp) {
 	case cloudprovider.AWS:
@@ -80,8 +86,6 @@ func main() {
 			log.With(zap.Error(err)).Fatalf("Failed to set up AWS metadata client")
 		}
 
-		issuer = aws.NewIssuer(log)
-
 	case cloudprovider.Azure:
 		diskPath, err = filepath.EvalSymlinks(azureStateDiskPath)
 		if err != nil {
@@ -93,15 +97,12 @@ func main() {
 			log.With(zap.Error).Fatalf("Failed to set up Azure metadata client")
 		}
 
-		issuer = azure.NewIssuer(log)
-
 	case cloudprovider.GCP:
 		diskPath, err = filepath.EvalSymlinks(gcpStateDiskPath)
 		if err != nil {
 			_ = exportPCRs()
 			log.With(zap.Error(err)).Fatalf("Unable to resolve GCP state disk path")
 		}
-		issuer = gcp.NewIssuer(log)
 		gcpMeta, err := gcpcloud.New(context.Background())
 		if err != nil {
 			log.With(zap.Error).Fatalf("Failed to create GCP metadata client")
@@ -115,13 +116,10 @@ func main() {
 		if err != nil {
 			log.With(zap.Error).Fatalf("Failed to create OpenStack metadata client")
 		}
-		// TODO(malt3): implement OpenStack quote issuer
-		issuer = qemu.NewIssuer(log)
 		_ = exportPCRs()
 
 	case cloudprovider.QEMU:
 		diskPath = qemuStateDiskPath
-		issuer = qemu.NewIssuer(log)
 		metadataClient = qemucloud.New()
 		_ = exportPCRs()
 

internal/attestation/azure/azure.go

@@ -18,19 +18,3 @@ Constellation supports multiple attestation technologies on Azure.
     Basic TPM attestation.
 */
 package azure
-
-import (
-	"github.com/edgelesssys/constellation/v2/internal/atls"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/snp"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/trustedlaunch"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
-)
-
-// NewIssuer returns an SNP issuer if it can successfully read the idkeydigest from the TPM.
-// Otherwise returns a Trusted Launch issuer.
-func NewIssuer(log vtpm.AttestationLogger) atls.Issuer {
-	if _, err := snp.GetIDKeyDigest(vtpm.OpenVTPM); err == nil {
-		return snp.NewIssuer(log)
-	}
-	return trustedlaunch.NewIssuer(log)
-}

internal/attestation/choose/choose.go

@@ -0,0 +1,66 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package choose
+
+import (
+	"fmt"
+
+	"github.com/edgelesssys/constellation/v2/internal/atls"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/aws"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/snp"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/trustedlaunch"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/gcp"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/idkeydigest"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/measurements"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/qemu"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
+	"github.com/edgelesssys/constellation/v2/internal/oid"
+)
+
+// Issuer returns the issuer for the given variant.
+func Issuer(variant oid.Getter, log vtpm.AttestationLogger) (atls.Issuer, error) {
+	switch variant {
+	case oid.AWSNitroTPM{}:
+		return aws.NewIssuer(log), nil
+	case oid.AzureTrustedLaunch{}:
+		return trustedlaunch.NewIssuer(log), nil
+	case oid.AzureSEVSNP{}:
+		return snp.NewIssuer(log), nil
+	case oid.GCPSEVES{}:
+		return gcp.NewIssuer(log), nil
+	case oid.QEMUVTPM{}:
+		return qemu.NewIssuer(log), nil
+	case oid.Dummy{}:
+		return atls.NewFakeIssuer(oid.Dummy{}), nil
+	default:
+		return nil, fmt.Errorf("unknown attestation variant: %s", variant)
+	}
+}
+
+// Validator returns the validator for the given variant.
+func Validator(
+	variant oid.Getter, measurements measurements.M,
+	idKeyDigest idkeydigest.IDKeyDigests, enfoceIDKeyDigest bool,
+	log vtpm.AttestationLogger,
+) (atls.Validator, error) {
+	switch variant {
+	case oid.AWSNitroTPM{}:
+		return aws.NewValidator(measurements, log), nil
+	case oid.AzureTrustedLaunch{}:
+		return trustedlaunch.NewValidator(measurements, log), nil
+	case oid.AzureSEVSNP{}:
+		return snp.NewValidator(measurements, idKeyDigest, enfoceIDKeyDigest, log), nil
+	case oid.GCPSEVES{}:
+		return gcp.NewValidator(measurements, log), nil
+	case oid.QEMUVTPM{}:
+		return qemu.NewValidator(measurements, log), nil
+	case oid.Dummy{}:
+		return atls.NewFakeValidator(oid.Dummy{}), nil
+	default:
+		return nil, fmt.Errorf("unknown attestation variant: %s", variant)
+	}
+}

internal/attestation/choose/choose_test.go

@@ -0,0 +1,114 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package choose
+
+import (
+	"encoding/asn1"
+	"testing"
+
+	"github.com/edgelesssys/constellation/v2/internal/oid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestIssuer(t *testing.T) {
+	testCases := map[string]struct {
+		variant oid.Getter
+		wantErr bool
+	}{
+		"aws-nitro-tpm": {
+			variant: oid.AWSNitroTPM{},
+		},
+		"azure-sev-snp": {
+			variant: oid.AzureSEVSNP{},
+		},
+		"azure-trusted-launch": {
+			variant: oid.AzureTrustedLaunch{},
+		},
+		"gcp-sev-es": {
+			variant: oid.GCPSEVES{},
+		},
+		"qemu-vtpm": {
+			variant: oid.QEMUVTPM{},
+		},
+		"dummy": {
+			variant: oid.Dummy{},
+		},
+		"unknown": {
+			variant: unknownVariant{},
+			wantErr: true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			assert := assert.New(t)
+			require := require.New(t)
+
+			issuer, err := Issuer(tc.variant, nil)
+
+			if tc.wantErr {
+				assert.Error(err)
+				return
+			}
+			require.NoError(err)
+			assert.True(issuer.OID().Equal(tc.variant.OID()))
+		})
+	}
+}
+
+func TestValidator(t *testing.T) {
+	testCases := map[string]struct {
+		variant oid.Getter
+		wantErr bool
+	}{
+		"aws-nitro-tpm": {
+			variant: oid.AWSNitroTPM{},
+		},
+		"azure-sev-snp": {
+			variant: oid.AzureSEVSNP{},
+		},
+		"azure-trusted-launch": {
+			variant: oid.AzureTrustedLaunch{},
+		},
+		"gcp-sev-es": {
+			variant: oid.GCPSEVES{},
+		},
+		"qemu-vtpm": {
+			variant: oid.QEMUVTPM{},
+		},
+		"dummy": {
+			variant: oid.Dummy{},
+		},
+		"unknown": {
+			variant: unknownVariant{},
+			wantErr: true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			assert := assert.New(t)
+			require := require.New(t)
+
+			validator, err := Validator(tc.variant, nil, nil, false, nil)
+
+			if tc.wantErr {
+				assert.Error(err)
+				return
+			}
+			require.NoError(err)
+			assert.True(validator.OID().Equal(tc.variant.OID()))
+		})
+	}
+}
+
+type unknownVariant struct{}
+
+func (unknownVariant) OID() asn1.ObjectIdentifier {
+	return asn1.ObjectIdentifier{1, 3, 9900, 9999, 9999}
+}

internal/constants/constants.go

@@ -31,6 +31,8 @@ const (
 	ConstellationSaltKey = "salt"
 	// ConstellationVerifyServiceUserData is the user data that the verification service includes in the attestation.
 	ConstellationVerifyServiceUserData = "VerifyService"
+	// AttestationVariant is the name of the environment variable that contains the attestation variant.
+	AttestationVariant = "CONSTEL_ATTESTATION_VARIANT"
 
 	//
 	// Ports.

verify/cmd/main.go

@@ -12,7 +12,7 @@ import (
 	"strconv"
 
 	"github.com/edgelesssys/constellation/v2/internal/attestation/aws"
-	"github.com/edgelesssys/constellation/v2/internal/attestation/azure"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/azure/snp"
 	"github.com/edgelesssys/constellation/v2/internal/attestation/gcp"
 	"github.com/edgelesssys/constellation/v2/internal/attestation/qemu"
 	"github.com/edgelesssys/constellation/v2/internal/cloud/cloudprovider"
@@ -39,7 +39,7 @@ func main() {
 	case cloudprovider.GCP:
 		issuer = gcp.NewIssuer(log)
 	case cloudprovider.Azure:
-		issuer = azure.NewIssuer(log)
+		issuer = snp.NewIssuer(log) // TODO: dynamic selection
 	case cloudprovider.QEMU:
 		issuer = qemu.NewIssuer(log)
 	default: