Add tests for doTPMAttestationFormat

acme/challenge.go

@@ -446,7 +446,7 @@ func deviceAttest01Validate(ctx context.Context, ch *Challenge, db DB, jwk *jose
 		az.Fingerprint = data.Fingerprint
 
 	case "tpm":
-		data, err := doTPMAttestationFormat(ctx, ch, db, jwk, &att)
+		data, err := doTPMAttestationFormat(ctx, prov, ch, jwk, &att)
 		if err != nil {
 			// TODO(hs): we should provide more details in the error reported to the client;
 			// "Attestation statement cannot be verified" is VERY generic. Also holds true for the other formats.
@@ -511,13 +511,7 @@ type tpmAttestationData struct {
 	Fingerprint          string
 }
 
-func doTPMAttestationFormat(ctx context.Context, ch *Challenge, db DB, jwk *jose.JSONWebKey, att *attestationObject) (*tpmAttestationData, error) {
+func doTPMAttestationFormat(ctx context.Context, prov Provisioner, ch *Challenge, jwk *jose.JSONWebKey, att *attestationObject) (*tpmAttestationData, error) {
-	p := MustProvisionerFromContext(ctx)
-	prov, ok := p.(*provisioner.ACME)
-	if !ok {
-		return nil, NewErrorISE("provisioner in context is not an ACME provisioner")
-	}
-
 	ver, ok := att.AttStatement["ver"].(string)
 	if !ok {
 		return nil, NewError(ErrorBadAttestationStatementType, "ver not present")
@@ -577,7 +571,7 @@ func doTPMAttestationFormat(ctx context.Context, ch *Challenge, db DB, jwk *jose
 
 	roots, ok := prov.GetAttestationRoots()
 	if !ok {
-		return nil, NewErrorISE("failed getting tpm attestation root CAs")
+		return nil, NewErrorISE("failed getting TPM attestation root CAs")
 	}
 
 	verifiedChains, err := akCert.Verify(x509.VerifyOptions{
@@ -605,24 +599,6 @@ func doTPMAttestationFormat(ctx context.Context, ch *Challenge, db DB, jwk *jose
 		return nil, NewError(ErrorBadAttestationStatementType, "AK certificate is missing Subject Alternative Name extension")
 	}
 
-	// TODO(hs): below code fails if there's a URI SAN, for example. Needs more complete parsing of SANS,
-	// or skip ASN1 tags that can't be parsed.
-	// san, err := x509ext.ParseSubjectAltName(sanExtension) // TODO(hs): move to a package under our control?
-	// if err != nil {
-	// 	return nil, WrapError(ErrorBadAttestationStatementType, err, "failed parsing Subject Alternative Name extension")
-	// }
-
-	// var permanentIdentifiers = make([]string, len(san.PermanentIdentifiers))
-	// for i, p := range san.PermanentIdentifiers {
-	// 	permanentIdentifiers[i] = p.IdentifierValue
-	// }
-
-	// TODO(hs): reenable this check when we want to enforce a PermanentIdentifier to be present in
-	// the AK certificate.
-	// if len(permanentIdentifiers) == 0 {
-	// 	return nil, NewError(ErrorBadAttestationStatementType, "AK certificate doesn't contain a PermanentIdentifier")
-	// }
-
 	// extract and validate pubArea, sig, certInfo and alg properties from the request body
 	pubArea, ok := att.AttStatement["pubArea"].([]byte)
 	if !ok {
@@ -680,7 +656,7 @@ func doTPMAttestationFormat(ctx context.Context, ch *Challenge, db DB, jwk *jose
 		return nil, WrapError(ErrorBadAttestationStatementType, err, "invalid certification parameters")
 	}
 
-	// decode the "certInfo" data
+	// decode the "certInfo" data. This won't fail, as it's also done as part of Verify().
 	tpmCertInfo, err := tpm2.DecodeAttestationData(certInfo)
 	if err != nil {
 		return nil, WrapError(ErrorBadAttestationStatementType, err, "failed decoding attestation data")
@@ -698,7 +674,7 @@ func doTPMAttestationFormat(ctx context.Context, ch *Challenge, db DB, jwk *jose
 		return nil, NewError(ErrorBadAttestationStatementType, "key authorization does not match")
 	}
 
-	// decode the (attested) public key and determine its fingerprint
+	// decode the (attested) public key and determine its fingerprint.  This won't fail, as it's also done as part of Verify().
 	pub, err := tpm2.DecodePublic(pubArea)
 	if err != nil {
 		return nil, WrapError(ErrorBadAttestationStatementType, err, "failed decoding pubArea")
@@ -712,7 +688,6 @@ func doTPMAttestationFormat(ctx context.Context, ch *Challenge, db DB, jwk *jose
 	data := &tpmAttestationData{
 		Certificate:    akCert,
 		VerifiedChains: verifiedChains,
-		//PermanentIdentifiers: permanentIdentifiers,
 	}
 
 	if data.Fingerprint, err = keyutil.Fingerprint(publicKey); err != nil {

acme/challenge_tpmsimulator_test.go

@@ -12,6 +12,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"encoding/pem"
+	"errors"
 	"net/url"
 	"testing"
 
@@ -63,6 +64,7 @@ func generateKeyID(t *testing.T, pub crypto.PublicKey) []byte {
 func mustAttestTPM(t *testing.T, keyAuthorization string) ([]byte, crypto.Signer, *x509.Certificate) {
 	t.Helper()
 	aca, err := minica.New(
+		minica.WithName("TPM Testing"),
 		minica.WithGetSignerFunc(
 			func() (crypto.Signer, error) {
 				return keyutil.GenerateSigner("RSA", "", 2048)
@@ -133,7 +135,7 @@ func mustAttestTPM(t *testing.T, keyAuthorization string) ([]byte, crypto.Signer
 		AttStatement: map[string]interface{}{
 			"ver":      "2.0",
 			"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
-			"alg":      int64(-257), // RSA
+			"alg":      int64(-257), // RS256
 			"sig":      params.CreateSignature,
 			"certInfo": params.CreateAttestation,
 			"pubArea":  params.Public,
@@ -292,3 +294,448 @@ func Test_deviceAttest01ValidateWithTPMSimulator(t *testing.T) {
 		})
 	}
 }
+
+func newBadAttestationStatementError(msg string) *Error {
+	return &Error{
+		Type:   "urn:ietf:params:acme:error:badAttestationStatement",
+		Status: 400,
+		Err:    errors.New(msg),
+	}
+}
+
+func newInternalServerError(msg string) *Error {
+	return &Error{
+		Type:   "urn:ietf:params:acme:error:serverInternal",
+		Status: 500,
+		Err:    errors.New(msg),
+	}
+}
+
+func Test_doTPMAttestationFormat(t *testing.T) {
+	ctx := context.Background()
+	aca, err := minica.New(
+		minica.WithName("TPM Testing"),
+		minica.WithGetSignerFunc(
+			func() (crypto.Signer, error) {
+				return keyutil.GenerateSigner("RSA", "", 2048)
+			},
+		),
+	)
+	require.NoError(t, err)
+	acaRoot := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: aca.Root.Raw})
+
+	// prepare simulated TPM and create an AK
+	stpm := newSimulatedTPM(t)
+	eks, err := stpm.GetEKs(context.Background())
+	require.NoError(t, err)
+	ak, err := stpm.CreateAK(context.Background(), "first-ak")
+	require.NoError(t, err)
+	require.NotNil(t, ak)
+
+	// extract the AK public key // TODO(hs): replace this when there's a simpler method to get the AK public key (e.g. ak.Public())
+	ap, err := ak.AttestationParameters(context.Background())
+	require.NoError(t, err)
+	akp, err := attest.ParseAKPublic(attest.TPMVersion20, ap.Public)
+	require.NoError(t, err)
+
+	// create template and sign certificate for the AK public key
+	keyID := generateKeyID(t, eks[0].Public())
+	template := &x509.Certificate{
+		Subject: pkix.Name{
+			CommonName: "testakcert",
+		},
+		PublicKey: akp.Public,
+		URIs: []*url.URL{
+			{Scheme: "urn", Opaque: "ek:sha256:" + base64.StdEncoding.EncodeToString(keyID)},
+		},
+	}
+	akCert, err := aca.Sign(template)
+	require.NoError(t, err)
+	require.NotNil(t, akCert)
+
+	templateMissingSAN := &x509.Certificate{
+		Subject: pkix.Name{
+			CommonName: "testakcertmissingsan",
+		},
+		PublicKey: akp.Public,
+	}
+	akCertMissingSAN, err := aca.Sign(templateMissingSAN)
+	require.NoError(t, err)
+	require.NotNil(t, akCert)
+
+	// generate a JWK and the key authorization value
+	jwk, err := jose.GenerateJWK("EC", "P-256", "ES256", "sig", "", 0)
+	require.NoError(t, err)
+	keyAuthorization, err := KeyAuthorization("token", jwk)
+	require.NoError(t, err)
+
+	// create a new key attested by the AK, while including
+	// the key authorization bytes as qualifying data.
+	keyAuthSum := sha256.Sum256([]byte(keyAuthorization))
+	config := tpm.AttestKeyConfig{
+		Algorithm:      "RSA",
+		Size:           2048,
+		QualifyingData: keyAuthSum[:],
+	}
+	key, err := stpm.AttestKey(context.Background(), "first-ak", "first-key", config)
+	require.NoError(t, err)
+	require.NotNil(t, key)
+	params, err := key.CertificationParameters(context.Background())
+	require.NoError(t, err)
+
+	signer, err := key.Signer(context.Background())
+	require.NoError(t, err)
+	fingerprint, err := keyutil.Fingerprint(signer.Public())
+	require.NoError(t, err)
+
+	// attest another key and get its certification parameters
+	anotherKey, err := stpm.AttestKey(context.Background(), "first-ak", "another-key", config)
+	require.NoError(t, err)
+	require.NotNil(t, key)
+	anotherKeyParams, err := anotherKey.CertificationParameters(context.Background())
+	require.NoError(t, err)
+
+	type args struct {
+		ctx  context.Context
+		prov Provisioner
+		ch   *Challenge
+		jwk  *jose.JSONWebKey
+		att  *attestationObject
+	}
+	tests := []struct {
+		name   string
+		args   args
+		want   *tpmAttestationData
+		expErr *Error
+	}{
+		{"ok", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), //
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, nil},
+		{"fail ver not present", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("ver not present")},
+		{"fail ver type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      []interface{}{},
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("ver not present")},
+		{"fail bogus ver", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "bogus",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError(`version "bogus" is not supported`)},
+		{"fail x5c not present", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c not present")},
+		{"fail x5c type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      [][]byte{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c not present")},
+		{"fail x5c empty", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c is empty")},
+		{"fail leaf type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "step",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{"leaf", aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c is malformed")},
+		{"fail leaf parse", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "step",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw[:100], aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c is malformed: x509: malformed certificate")},
+		{"fail intermediate type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "step",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, "intermediate"},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c is malformed")},
+		{"fail intermediate parse", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "step",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw[:100]},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c is malformed: x509: malformed certificate")},
+		{"fail roots", args{ctx, mustAttestationProvisioner(t, nil), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newInternalServerError("failed getting TPM attestation root CAs")},
+		{"fail verify", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "step",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("x5c is not valid: x509: certificate signed by unknown authority")},
+		{"fail missing SAN extension", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCertMissingSAN.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("AK certificate is missing Subject Alternative Name extension")},
+		{"fail pubArea not present", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+			},
+		}}, nil, newBadAttestationStatementError("invalid pubArea in attestation statement")},
+		{"fail pubArea type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  []interface{}{},
+			},
+		}}, nil, newBadAttestationStatementError("invalid pubArea in attestation statement")},
+		{"fail pubArea empty", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  []byte{},
+			},
+		}}, nil, newBadAttestationStatementError("pubArea is empty")},
+		{"fail sig not present", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid sig in attestation statement")},
+		{"fail sig type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      []interface{}{},
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid sig in attestation statement")},
+		{"fail sig empty", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      []byte{},
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("sig is empty")},
+		{"fail certInfo not present", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":     "2.0",
+				"x5c":     []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":     int64(-257), // RS256
+				"sig":     params.CreateSignature,
+				"pubArea": params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid certInfo in attestation statement")},
+		{"fail certInfo type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": []interface{}{},
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid certInfo in attestation statement")},
+		{"fail certInfo empty", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": []byte{},
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("certInfo is empty")},
+		{"fail alg not present", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid alg in attestation statement")},
+		{"fail alg type", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(0), // invalid alg
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid alg 0 in attestation statement")},
+		{"fail attestation verification", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  anotherKeyParams.Public,
+			},
+		}}, nil, newBadAttestationStatementError("invalid certification parameters: certification refers to a different key")},
+		{"fail keyAuthorization", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "token"}, &jose.JSONWebKey{Key: []byte("not an asymmetric key")}, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), // RS256
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newInternalServerError("failed creating key auth digest: error generating JWK thumbprint: square/go-jose: unknown key type '[]uint8'")},
+		{"fail different keyAuthorization", args{ctx, mustAttestationProvisioner(t, acaRoot), &Challenge{Token: "aDifferentToken"}, jwk, &attestationObject{
+			Format: "tpm",
+			AttStatement: map[string]interface{}{
+				"ver":      "2.0",
+				"x5c":      []interface{}{akCert.Raw, aca.Intermediate.Raw},
+				"alg":      int64(-257), //
+				"sig":      params.CreateSignature,
+				"certInfo": params.CreateAttestation,
+				"pubArea":  params.Public,
+			},
+		}}, nil, newBadAttestationStatementError("key authorization does not match")},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := doTPMAttestationFormat(tt.args.ctx, tt.args.prov, tt.args.ch, tt.args.jwk, tt.args.att)
+			if tt.expErr != nil {
+				var ae *Error
+				if assert.True(t, errors.As(err, &ae)) {
+					assert.EqualError(t, err, tt.expErr.Error())
+					assert.Equal(t, ae.StatusCode(), tt.expErr.StatusCode())
+					assert.Equal(t, ae.Type, tt.expErr.Type)
+				}
+				assert.Nil(t, got)
+				return
+			}
+
+			assert.NoError(t, err)
+			if assert.NotNil(t, got) {
+				assert.Equal(t, akCert, got.Certificate)
+				assert.Equal(t, [][]*x509.Certificate{
+					{
+						akCert, aca.Intermediate, aca.Root,
+					},
+				}, got.VerifiedChains)
+				assert.Equal(t, fingerprint, got.Fingerprint)
+				assert.Empty(t, got.PermanentIdentifiers) // currently expected to be always empty
+			}
+		})
+	}
+}