measurement-reader: unify TPM & TDX sorting

measurement-reader/internal/sorted/sorted.go

@@ -4,11 +4,67 @@ Copyright (c) Edgeless Systems GmbH
 SPDX-License-Identifier: AGPL-3.0-only
 */
 
-// Type definition for sorted measurements.
+// Package sorted defines a type for print-friendly sorted measurements and allows sorting TPM and TDX measurements.
 package sorted
 
+import (
+	"fmt"
+	"sort"
+
+	"github.com/edgelesssys/constellation/v2/internal/attestation/measurements"
+)
+
 // Measurement wraps a measurement custom index and value.
 type Measurement struct {
 	Index string
 	Value []byte
 }
+
+// MeasurementType are the supported attestation types we can sort.
+type MeasurementType uint32
+
+const (
+	TPM MeasurementType = iota
+	TDX
+)
+
+// SortMeasurements returns the sorted measurements for either TPM or TDX measurements.
+func SortMeasurements(m measurements.M, measurementType MeasurementType) []Measurement {
+	if measurementType != TPM && measurementType != TDX {
+		return nil
+	}
+
+	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 sortedMeasurements []Measurement
+
+	for _, idx := range keys {
+		var index string
+		switch measurementType {
+		case TPM:
+			index = fmt.Sprintf("PCR[%02d]", idx)
+		case TDX:
+			// idx 0 is MRTD
+			if idx == 0 {
+				index = "MRTD"
+				break
+			}
+			// RTMR 0 starts at idx 1, so we have to subtract by one here.
+			index = fmt.Sprintf("RTMR[%01d]", idx-1)
+		}
+
+		expected := m[idx].Expected
+		sortedMeasurements = append(sortedMeasurements, Measurement{
+			Index: index,
+			Value: expected[:],
+		})
+	}
+
+	return sortedMeasurements
+}

measurement-reader/internal/sorted/sorted_test.go

@@ -0,0 +1,124 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package sorted
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/edgelesssys/constellation/v2/internal/attestation/measurements"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSortMeasurements(t *testing.T) {
+	testCases := map[string]struct {
+		measurementType MeasurementType
+		input           measurements.M
+		want            []Measurement
+	}{
+		"pre sorted TPM": {
+			measurementType: TPM,
+			input: measurements.M{
+				0: measurements.WithAllBytes(0x11, measurements.Enforce),
+				1: measurements.WithAllBytes(0x22, measurements.Enforce),
+				2: measurements.WithAllBytes(0x33, measurements.Enforce),
+			},
+			want: []Measurement{
+				{
+					Index: "PCR[00]",
+					Value: bytes.Repeat([]byte{0x11}, 32),
+				},
+				{
+					Index: "PCR[01]",
+					Value: bytes.Repeat([]byte{0x22}, 32),
+				},
+				{
+					Index: "PCR[02]",
+					Value: bytes.Repeat([]byte{0x33}, 32),
+				},
+			},
+		},
+		"unsorted TPM": {
+			measurementType: TPM,
+			input: measurements.M{
+				1: measurements.WithAllBytes(0x22, measurements.Enforce),
+				0: measurements.WithAllBytes(0x11, measurements.Enforce),
+				2: measurements.WithAllBytes(0x33, measurements.Enforce),
+			},
+			want: []Measurement{
+				{
+					Index: "PCR[00]",
+					Value: bytes.Repeat([]byte{0x11}, 32),
+				},
+				{
+					Index: "PCR[01]",
+					Value: bytes.Repeat([]byte{0x22}, 32),
+				},
+				{
+					Index: "PCR[02]",
+					Value: bytes.Repeat([]byte{0x33}, 32),
+				},
+			},
+		},
+		"pre sorted TDX": {
+			measurementType: TDX,
+			input: measurements.M{
+				0: measurements.WithAllBytes(0x11, false),
+				1: measurements.WithAllBytes(0x22, false),
+				2: measurements.WithAllBytes(0x33, false),
+			},
+			want: []Measurement{
+				{
+					Index: "MRTD",
+					Value: bytes.Repeat([]byte{0x11}, 32),
+				},
+				{
+					Index: "RTMR[0]",
+					Value: bytes.Repeat([]byte{0x22}, 32),
+				},
+				{
+					Index: "RTMR[1]",
+					Value: bytes.Repeat([]byte{0x33}, 32),
+				},
+			},
+		},
+		"unsorted TDX": {
+			measurementType: TDX,
+			input: measurements.M{
+				1: measurements.WithAllBytes(0x22, false),
+				0: measurements.WithAllBytes(0x11, false),
+				2: measurements.WithAllBytes(0x33, false),
+			},
+			want: []Measurement{
+				{
+					Index: "MRTD",
+					Value: bytes.Repeat([]byte{0x11}, 32),
+				},
+				{
+					Index: "RTMR[0]",
+					Value: bytes.Repeat([]byte{0x22}, 32),
+				},
+				{
+					Index: "RTMR[1]",
+					Value: bytes.Repeat([]byte{0x33}, 32),
+				},
+			},
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			assert := assert.New(t)
+
+			got := SortMeasurements(tc.input, tc.measurementType)
+			for i := range got {
+				assert.Equal(got[i].Index, tc.want[i].Index)
+				assert.Equal(got[i].Value, tc.want[i].Value)
+			}
+		})
+	}
+}