Add measurement reader (#1381)

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

measurement-reader/cmd/main.go

@@ -0,0 +1,45 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/edgelesssys/constellation/v2/internal/constants"
+	"github.com/edgelesssys/constellation/v2/internal/logger"
+	"github.com/edgelesssys/constellation/v2/internal/oid"
+	"github.com/edgelesssys/constellation/v2/measurement-reader/internal/sorted"
+	"github.com/edgelesssys/constellation/v2/measurement-reader/internal/tpm"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+func main() {
+	log := logger.New(logger.JSONLog, zapcore.InfoLevel)
+	variant := os.Getenv(constants.AttestationVariant)
+	attestationVariant, err := oid.FromString(variant)
+	if err != nil {
+		log.With(zap.Error(err)).Fatalf("Failed to parse attestation variant")
+	}
+
+	var m []sorted.Measurement
+	switch attestationVariant {
+	case oid.AWSNitroTPM{}, oid.AzureSEVSNP{}, oid.AzureTrustedLaunch{}, oid.GCPSEVES{}, oid.QEMUVTPM{}:
+		m, err = tpm.Measurements()
+		if err != nil {
+			log.With(zap.Error(err)).Fatalf("Failed to read TPM measurements")
+		}
+	default:
+		log.With(zap.String("attestationVariant", variant)).Fatalf("Unsupported attestation variant")
+	}
+
+	fmt.Println("Measurements:")
+	for _, measurement := range m {
+		fmt.Printf("\t%s : 0x%0X\n", measurement.Index, measurement.Value)
+	}
+}