attestation: clear certificate cache in azure snp

The unittest was flacky as testcases with valid certs in the getter property lead to those certs being cached inside the trust module. Other testcases however, may want to explicitly use invalid certs. The cache interferes with this. Co-authored-by: Moritz Sanft <[email protected]>
edgelesssys · Nov 8, 2023 · 8341db3 · 8341db3
1 parent 45df17d
commit 8341db3
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Showing 2 changed files with 24 additions and 17 deletions.
diff --git a/internal/attestation/azure/snp/BUILD.bazel b/internal/attestation/azure/snp/BUILD.bazel
@@ -60,6 +60,7 @@ go_test(
         "@com_github_google_go_sev_guest//proto/sevsnp",
         "@com_github_google_go_sev_guest//validate",
         "@com_github_google_go_sev_guest//verify",
+        "@com_github_google_go_sev_guest//verify/trust",
         "@com_github_google_go_tpm//legacy/tpm2",
         "@com_github_google_go_tpm_tools//client",
         "@com_github_google_go_tpm_tools//proto/attest",

diff --git a/internal/attestation/azure/snp/validator_test.go b/internal/attestation/azure/snp/validator_test.go
@@ -34,6 +34,7 @@ import (
 	spb "github.com/google/go-sev-guest/proto/sevsnp"
 	"github.com/google/go-sev-guest/validate"
 	"github.com/google/go-sev-guest/verify"
+	"github.com/google/go-sev-guest/verify/trust"
 	"github.com/google/go-tpm-tools/client"
 	"github.com/google/go-tpm-tools/proto/attest"
 	"github.com/google/go-tpm/legacy/tpm2"
@@ -284,6 +285,9 @@ func TestInstanceInfoAttestation(t *testing.T) {
 			assert := assert.New(t)
 			require := require.New(t)
 
+			// This is important. Without this call, the trust module caches certificates across testcases.
+			defer trust.ClearProductCertCache()
+
 			instanceInfo := azureInstanceInfo{
 				AttestationReport: tc.report,
 				CertChain:         tc.certChain,
@@ -564,22 +568,21 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 	if cgo == "0" {
 		t.Skip("skipping test because CGO is disabled and tpm simulator requires it")
 	}
-	require := require.New(t)
 
 	tpm, err := simulator.OpenSimulatedTPM()
-	require.NoError(err)
+	require.NoError(t, err)
 	defer tpm.Close()
 	key, err := client.AttestationKeyRSA(tpm)
-	require.NoError(err)
+	require.NoError(t, err)
 	defer key.Close()
 	akPub, err := key.PublicArea().Encode()
-	require.NoError(err)
+	require.NoError(t, err)
 
 	defaultCfg := config.DefaultForAzureSEVSNP()
 	defaultReport := hex.EncodeToString(testdata.AttestationReport)
 	defaultRuntimeData := hex.EncodeToString(testdata.RuntimeData)
 	defaultIDKeyDigestOld, err := hex.DecodeString("57e229e0ffe5fa92d0faddff6cae0e61c926fc9ef9afd20a8b8cfcf7129db9338cbe5bf3f6987733a2bf65d06dc38fc1")
-	require.NoError(err)
+	require.NoError(t, err)
 	defaultIDKeyDigest := idkeydigest.NewList([][]byte{defaultIDKeyDigestOld})
 	defaultVerifier := &stubAttestationVerifier{}
 	skipVerifier := &stubAttestationVerifier{skipCheck: true}
@@ -588,12 +591,12 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 	// reportTransformer unpacks the hex-encoded report, applies the given transformations and re-encodes it.
 	reportTransformer := func(reportHex string, transformations func(*spb.Report)) string {
 		rawReport, err := hex.DecodeString(reportHex)
-		require.NoError(err)
+		require.NoError(t, err)
 		report, err := abi.ReportToProto(rawReport)
-		require.NoError(err)
+		require.NoError(t, err)
 		transformations(report)
 		reportBytes, err := abi.ReportToAbiBytes(report)
-		require.NoError(err)
+		require.NoError(t, err)
 		return hex.EncodeToString(reportBytes)
 	}
 
@@ -746,6 +749,7 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 				},
 				nil,
 			),
+			wantErr: true,
 		},
 		"invalid runtime data": {
 			report:               defaultReport,
@@ -821,7 +825,7 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 				defaultCfg.MicrocodeVersion.Value = 10
 				launchTcb.UcodeSpl = 9
 				newLaunchTcb, err := kds.ComposeTCBParts(launchTcb)
-				require.NoError(err)
+				require.NoError(t, err)
 				r.LaunchTcb = uint64(newLaunchTcb)
 			}),
 			runtimeData:          defaultRuntimeData,
@@ -845,7 +849,7 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 				reportedTcb := kds.DecomposeTCBVersion(kds.TCBVersion(r.ReportedTcb))
 				reportedTcb.UcodeSpl = defaultCfg.MicrocodeVersion.Value - 1
 				newReportedTcb, err := kds.ComposeTCBParts(reportedTcb)
-				require.NoError(err)
+				require.NoError(t, err)
 				r.ReportedTcb = uint64(newReportedTcb)
 			}),
 			runtimeData:          defaultRuntimeData,
@@ -889,7 +893,7 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 				currentTcb := kds.DecomposeTCBVersion(kds.TCBVersion(r.CurrentTcb))
 				currentTcb.UcodeSpl = 0x5c // testdata.AzureThimVCEK has ucode version 0x5d
 				newCurrentTcb, err := kds.ComposeTCBParts(currentTcb)
-				require.NoError(err)
+				require.NoError(t, err)
 				r.CurrentTcb = uint64(newCurrentTcb)
 			}),
 			runtimeData:          defaultRuntimeData,
@@ -976,14 +980,16 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 	for name, tc := range testCases {
 		t.Run(name, func(t *testing.T) {
 			assert := assert.New(t)
+			require := require.New(t)
+
+			// This is important. Without this call, the trust module caches certificates across testcases.
+			defer trust.ClearProductCertCache()
 
 			instanceInfo, err := newStubAzureInstanceInfo(tc.vcek, tc.certChain, tc.report, tc.runtimeData)
-			assert.NoError(err)
+			require.NoError(err)
 
 			statement, err := json.Marshal(instanceInfo)
-			if err != nil {
-				assert.Error(err)
-			}
+			require.NoError(err)
 
 			attDoc := vtpm.AttestationDocument{
 				InstanceInfo: statement,
@@ -1008,12 +1014,12 @@ func TestTrustedKeyFromSNP(t *testing.T) {
 
 			key, err := validator.getTrustedKey(context.Background(), attDoc, nil)
 			if tc.wantErr {
-				require.Error(err)
+				assert.Error(err)
 				if tc.assertion != nil {
 					tc.assertion(assert, err)
 				}
 			} else {
-				require.NoError(err)
+				assert.NoError(err)
 				assert.NotNil(key)
 			}
 		})