start TPM support

client/internal/tpm/tpmtest/tpmtest.go

@@ -0,0 +1,48 @@
+// Package tpmtest builds TSS2 key files for tests, with or without a TPM behind them.
+package tpmtest
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"testing"
+
+	"github.com/google/go-tpm/legacy/tpm2"
+	"github.com/stretchr/testify/require"
+	"go.step.sm/crypto/tpm/tss2"
+)
+
+const p256Bytes = 32
+
+// SigningTemplate is the public area of an unrestricted P-256 signing key with no fixed
+// scheme, the shape tpm2-openssl creates certificate keys in.
+func SigningTemplate() tpm2.Public {
+	return tpm2.Public{
+		Type:          tpm2.AlgECC,
+		NameAlg:       tpm2.AlgSHA256,
+		Attributes:    tpm2.FlagSign | tpm2.FlagFixedTPM | tpm2.FlagFixedParent | tpm2.FlagSensitiveDataOrigin | tpm2.FlagUserWithAuth | tpm2.FlagNoDA,
+		ECCParameters: &tpm2.ECCParams{CurveID: tpm2.CurveNISTP256},
+	}
+}
+
+// KeyPEM encodes pub as a TSS2 PRIVATE KEY over a placeholder private blob: it parses
+// and reports pub, but no TPM can load it.
+func KeyPEM(t *testing.T, pub *ecdsa.PublicKey, opts ...tss2.TPMOption) string {
+	t.Helper()
+	require.Equal(t, elliptic.P256(), pub.Curve, "fixture keys must be P-256")
+	area := SigningTemplate()
+	area.ECCParameters.Point = tpm2.ECPoint{
+		XRaw: pub.X.FillBytes(make([]byte, p256Bytes)),
+		YRaw: pub.Y.FillBytes(make([]byte, p256Bytes)),
+	}
+	encoded, err := area.Encode()
+	require.NoError(t, err)
+	return EncodePEM(t, encoded, []byte("placeholder"), opts...)
+}
+
+// EncodePEM wraps the public and private blobs TPM2_Create returned into a TSS2 PRIVATE KEY.
+func EncodePEM(t *testing.T, public, private []byte, opts ...tss2.TPMOption) string {
+	t.Helper()
+	pemBytes, err := tss2.New(public, private, opts...).EncodeToMemory()
+	require.NoError(t, err)
+	return string(pemBytes)
+}