cli: print ordered measurements list during constellation verify (#…

…2302) * Print measurements as ordered list during verify * Fix missing safety check in AWS attestation validation --------- Signed-off-by: Daniel Weiße <[email protected]>
edgelesssys · Sep 8, 2023 · 9765003 · 9765003
1 parent 0eb9ca2
commit 9765003
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Showing 4 changed files with 112 additions and 9 deletions.
diff --git a/cli/internal/cmd/BUILD.bazel b/cli/internal/cmd/BUILD.bazel
@@ -160,6 +160,7 @@ go_test(
         "//internal/versions",
         "//operators/constellation-node-operator/api/v1alpha1",
         "//verify/verifyproto",
+        "@com_github_google_go_tpm_tools//proto/tpm",
         "@com_github_spf13_afero//:afero",
         "@com_github_spf13_cobra//:cobra",
         "@com_github_stretchr_testify//assert",

diff --git a/cli/internal/cmd/verify.go b/cli/internal/cmd/verify.go
@@ -19,6 +19,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -381,19 +382,23 @@ func (f *attestationDocFormatterImpl) parseCerts(b *strings.Builder, certTypeNam
 // parseQuotes parses the base64-encoded quotes and writes their details to the output builder.
 func (f *attestationDocFormatterImpl) parseQuotes(b *strings.Builder, quotes []*tpmProto.Quote, expectedPCRs measurements.M) error {
 	writeIndentfln(b, 1, "Quote:")
-	for pcrNum, expectedPCR := range expectedPCRs {
+
+	var pcrNumbers []uint32
+	for pcrNum := range expectedPCRs {
+		pcrNumbers = append(pcrNumbers, pcrNum)
+	}
+	sort.Slice(pcrNumbers, func(i, j int) bool { return pcrNumbers[i] < pcrNumbers[j] })
+
+	for _, pcrNum := range pcrNumbers {
+		expectedPCR := expectedPCRs[pcrNum]
 		pcrIdx, err := vtpm.GetSHA256QuoteIndex(quotes)
 		if err != nil {
 			return fmt.Errorf("get SHA256 quote index: %w", err)
 		}
 
-		if quotes[pcrIdx] == nil {
-			return fmt.Errorf("quote %d is nil", pcrIdx)
-		}
-
-		actualPCR := quotes[pcrIdx].Pcrs.Pcrs[pcrNum]
-		if err != nil {
-			return fmt.Errorf("decode PCR %d: %w", pcrNum, err)
+		actualPCR, ok := quotes[pcrIdx].Pcrs.Pcrs[pcrNum]
+		if !ok {
+			return fmt.Errorf("PCR %d not found in quote", pcrNum)
 		}
 		writeIndentfln(b, 2, "PCR %d (Strict: %t):", pcrNum, !expectedPCR.ValidationOpt)
 		writeIndentfln(b, 3, "Expected:\t%x", expectedPCR.Expected)

diff --git a/cli/internal/cmd/verify_test.go b/cli/internal/cmd/verify_test.go
@@ -29,6 +29,7 @@ import (
 	"github.com/edgelesssys/constellation/v2/internal/grpc/testdialer"
 	"github.com/edgelesssys/constellation/v2/internal/logger"
 	"github.com/edgelesssys/constellation/v2/verify/verifyproto"
+	tpmProto "github.com/google/go-tpm-tools/proto/tpm"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -466,3 +467,93 @@ func TestAddPortIfMissing(t *testing.T) {
 		})
 	}
 }
+
+func TestParseQuotes(t *testing.T) {
+	testCases := map[string]struct {
+		quotes       []*tpmProto.Quote
+		expectedPCRs measurements.M
+		wantOutput   string
+		wantErr      bool
+	}{
+		"parse quotes in order": {
+			quotes: []*tpmProto.Quote{
+				{
+					Pcrs: &tpmProto.PCRs{
+						Hash: tpmProto.HashAlgo_SHA256,
+						Pcrs: map[uint32][]byte{
+							0: {0x00},
+							1: {0x01},
+						},
+					},
+				},
+			},
+			expectedPCRs: measurements.M{
+				0: measurements.WithAllBytes(0x00, measurements.Enforce, 1),
+				1: measurements.WithAllBytes(0x01, measurements.WarnOnly, 1),
+			},
+			wantOutput: "\tQuote:\n\t\tPCR 0 (Strict: true):\n\t\t\tExpected:\t00\n\t\t\tActual:\t\t00\n\t\tPCR 1 (Strict: false):\n\t\t\tExpected:\t01\n\t\t\tActual:\t\t01\n",
+		},
+		"additional quotes are skipped": {
+			quotes: []*tpmProto.Quote{
+				{
+					Pcrs: &tpmProto.PCRs{
+						Hash: tpmProto.HashAlgo_SHA256,
+						Pcrs: map[uint32][]byte{
+							0: {0x00},
+							1: {0x01},
+							2: {0x02},
+							3: {0x03},
+						},
+					},
+				},
+			},
+			expectedPCRs: measurements.M{
+				0: measurements.WithAllBytes(0x00, measurements.Enforce, 1),
+				1: measurements.WithAllBytes(0x01, measurements.WarnOnly, 1),
+			},
+			wantOutput: "\tQuote:\n\t\tPCR 0 (Strict: true):\n\t\t\tExpected:\t00\n\t\t\tActual:\t\t00\n\t\tPCR 1 (Strict: false):\n\t\t\tExpected:\t01\n\t\t\tActual:\t\t01\n",
+		},
+		"missing quotes error": {
+			quotes: []*tpmProto.Quote{
+				{
+					Pcrs: &tpmProto.PCRs{
+						Hash: tpmProto.HashAlgo_SHA256,
+						Pcrs: map[uint32][]byte{
+							0: {0x00},
+						},
+					},
+				},
+			},
+			expectedPCRs: measurements.M{
+				0: measurements.WithAllBytes(0x00, measurements.Enforce, 1),
+				1: measurements.WithAllBytes(0x01, measurements.WarnOnly, 1),
+			},
+			wantErr: true,
+		},
+		"no quotes error": {
+			quotes: []*tpmProto.Quote{},
+			expectedPCRs: measurements.M{
+				0: measurements.WithAllBytes(0x00, measurements.Enforce, 1),
+				1: measurements.WithAllBytes(0x01, measurements.WarnOnly, 1),
+			},
+			wantErr: true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			assert := assert.New(t)
+
+			b := &strings.Builder{}
+			parser := &attestationDocFormatterImpl{}
+
+			err := parser.parseQuotes(b, tc.quotes, tc.expectedPCRs)
+			if tc.wantErr {
+				assert.Error(err)
+			} else {
+				assert.NoError(err)
+				assert.Equal(tc.wantOutput, b.String())
+			}
+		})
+	}
+}
diff --git a/internal/attestation/aws/snp/validator.go b/internal/attestation/aws/snp/validator.go
@@ -80,12 +80,18 @@ func (v *Validator) tpmEnabled(attestation vtpm.AttestationDocument, _ *attest.M
 	if err != nil {
 		return err
 	}
+	if len(imageOutput.Images) == 0 {
+		return fmt.Errorf("aws image %s not found", imageID)
+	}
+	if len(imageOutput.Images) > 1 {
+		return fmt.Errorf("found multiple image references for image ID %s", imageID)
+	}
 
 	if imageOutput.Images[0].TpmSupport == "v2.0" {
 		return nil
 	}
 
-	return fmt.Errorf("iam image %s does not support TPM v2.0", imageID)
+	return fmt.Errorf("aws image %s does not support TPM v2.0", imageID)
 }
 
 func getEC2Client(ctx context.Context, region string) (awsMetadataAPI, error) {