Support for application signing keys (#201)

attest/application_key_test.go

@@ -0,0 +1,171 @@
+// Copyright 2021 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+// +build !localtest !tpm12
+// +build cgo
+
+// NOTE: simulator requires cgo, hence the build tag.
+
+package attest
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rand"
+	"crypto/x509"
+	"encoding/asn1"
+	"math/big"
+	"testing"
+)
+
+func TestSimTPM20KeyCreateAndLoad(t *testing.T) {
+	sim, tpm := setupSimulatedTPM(t)
+	defer sim.Close()
+	testKeyCreateAndLoad(t, tpm)
+}
+
+func TestTPM20KeyCreateAndLoad(t *testing.T) {
+	if !*testLocal {
+		t.SkipNow()
+	}
+	tpm, err := OpenTPM(nil)
+	if err != nil {
+		t.Fatalf("OpenTPM() failed: %v", err)
+	}
+	defer tpm.Close()
+	testKeyCreateAndLoad(t, tpm)
+}
+
+func testKeyCreateAndLoad(t *testing.T, tpm *TPM) {
+	ak, err := tpm.NewAK(nil)
+	if err != nil {
+		t.Fatalf("NewAK() failed: %v", err)
+	}
+	sk, err := tpm.NewKey(ak, nil)
+	if err != nil {
+		t.Fatalf("NewKey() failed: %v", err)
+	}
+	defer sk.Close()
+
+	enc, err := sk.Marshal()
+	if err != nil {
+		t.Fatalf("sk.Marshal() failed: %v", err)
+	}
+	if err := sk.Close(); err != nil {
+		t.Fatalf("sk.Close() failed: %v", err)
+	}
+
+	loaded, err := tpm.LoadKey(enc)
+	if err != nil {
+		t.Fatalf("LoadKey() failed: %v", err)
+	}
+	defer loaded.Close()
+
+	k1, k2 := sk.key.(*wrappedKey20), loaded.key.(*wrappedKey20)
+	if !bytes.Equal(k1.public, k2.public) {
+		t.Error("Original & loaded Key public blobs did not match.")
+		t.Logf("Original = %v", k1.public)
+		t.Logf("Loaded   = %v", k2.public)
+	}
+
+	priv1, err := sk.Private(sk.Public())
+	if err != nil {
+		t.Fatalf("sk.Private() failed: %v", err)
+	}
+	signer1, ok := priv1.(crypto.Signer)
+	if !ok {
+		t.Fatalf("want crypto.Signer, got %T", priv1)
+	}
+	pk1, err := x509.MarshalPKIXPublicKey(signer1.Public())
+	if err != nil {
+		t.Fatalf("cannot marshal public key: %v", err)
+	}
+
+	priv2, err := loaded.Private(loaded.Public())
+	if err != nil {
+		t.Fatalf("loaded.Private() failed: %v", err)
+	}
+	signer2, ok := priv2.(crypto.Signer)
+	if !ok {
+		t.Fatalf("want crypto.Signer, got %T", priv2)
+	}
+	pk2, err := x509.MarshalPKIXPublicKey(signer2.Public())
+	if err != nil {
+		t.Fatalf("cannot marshal public key: %v", err)
+	}
+
+	if !bytes.Equal(pk1, pk2) {
+		t.Error("public keys do not match")
+	}
+}
+
+func TestSimTPM20KeySign(t *testing.T) {
+	sim, tpm := setupSimulatedTPM(t)
+	defer sim.Close()
+	testKeySign(t, tpm)
+}
+
+func TestTPM20KeySign(t *testing.T) {
+	if !*testLocal {
+		t.SkipNow()
+	}
+	tpm, err := OpenTPM(nil)
+	if err != nil {
+		t.Fatalf("OpenTPM() failed: %v", err)
+	}
+	defer tpm.Close()
+	testKeySign(t, tpm)
+}
+
+func testKeySign(t *testing.T, tpm *TPM) {
+	ak, err := tpm.NewAK(nil)
+	if err != nil {
+		t.Fatalf("NewAK() failed: %v", err)
+	}
+	sk, err := tpm.NewKey(ak, nil)
+	if err != nil {
+		t.Fatalf("NewKey() failed: %v", err)
+	}
+	defer sk.Close()
+
+	pub := sk.Public()
+	priv, err := sk.Private(pub)
+	if err != nil {
+		t.Fatalf("sk.Private() failed: %v", err)
+	}
+	signer, ok := priv.(crypto.Signer)
+	if !ok {
+		t.Fatalf("want crypto.Signer, got %T", priv)
+	}
+	digest := []byte("12345678901234567890123456789012")
+	sig, err := signer.Sign(rand.Reader, digest, nil)
+	if !ok {
+		t.Fatalf("signer.Sign() failed: %v", err)
+	}
+
+	parsed := struct{ R, S *big.Int }{}
+	_, err = asn1.Unmarshal(sig, &parsed)
+	if err != nil {
+		t.Fatalf("signature parsing failed: %v", err)
+	}
+
+	pubECDSA, ok := pub.(*ecdsa.PublicKey)
+	if !ok {
+		t.Fatalf("want *ecdsa.PublicKey, got %T", pub)
+	}
+	if !ecdsa.Verify(pubECDSA, digest[:], parsed.R, parsed.S) {
+		t.Fatalf("ecdsa.Verify() failed")
+	}
+}