measurement-reader: add support for TDX

measurement-reader/internal/tdx/tdx.go

@@ -0,0 +1,58 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+// Package tdx reads measurements from an Intel TDX guest.
+package tdx
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/edgelesssys/constellation/v2/internal/attestation/measurements"
+	"github.com/edgelesssys/constellation/v2/internal/attestation/tdx"
+	"github.com/edgelesssys/constellation/v2/measurement-reader/internal/sorted"
+)
+
+// Measurements returns a sorted list of TDX runtime measurements.
+func Measurements() ([]sorted.Measurement, error) {
+	m, err := tdx.GetSelectedMeasurements(tdx.Open, []int{0, 1, 2, 3, 4})
+	if err != nil {
+		return nil, err
+	}
+
+	return sortMeasurements(m), nil
+}
+
+func sortMeasurements(m measurements.M) []sorted.Measurement {
+	keys := make([]uint32, 0, len(m))
+	for idx := range m {
+		keys = append(keys, idx)
+	}
+	sort.Slice(keys, func(i, j int) bool {
+		return keys[i] < keys[j]
+	})
+
+	var measurements []sorted.Measurement
+	for _, idx := range keys {
+		expected := m[idx].Expected
+
+		// Index 0   == MRTD
+		// Index 1-5 == RTMR[0-4]
+		var index string
+		if (idx) == 0 {
+			index = "MRTD"
+		} else {
+			index = fmt.Sprintf("RTMR[%01d]", idx-1)
+		}
+
+		measurements = append(measurements, sorted.Measurement{
+			Index: index,
+			Value: expected[:],
+		})
+	}
+
+	return measurements
+}