Fix GCP metadata errors crashing Teleport

lib/cloud/gcp/vm_test.go

@@ -73,7 +73,8 @@ func TestConvertAPIError(t *testing.T) {
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			require.True(t, trace.IsAccessDenied(convertAPIError(tc.err)))
+			err := convertAPIError(tc.err)
+			require.True(t, trace.IsAccessDenied(err), "unexpected error of type %T: %v", tc.err, err)
 			require.Contains(t, tc.err.Error(), "abcd1234")
 		})
 	}

lib/cloud/imds/gcp/imds.go

@@ -76,12 +76,23 @@ func NewInstanceMetadataClient(ctx context.Context) (*InstanceMetadataClient, er
 
 // IsAvailable checks if instance metadata is available.
 func (client *InstanceMetadataClient) IsAvailable(ctx context.Context) bool {
-	instanceData, err := client.getMetadata(ctx, "instance")
-	return err == nil && instanceData != ""
+	_, err := client.getNumericID(ctx)
+	return err == nil
 }
 
-// GetTags gets all of the GCP instance's labels (note: these are separate from
-// its tags, which we do not use).
+func (client *InstanceMetadataClient) getNumericID(ctx context.Context) (uint64, error) {
+	idStr, err := client.GetID(ctx)
+	if err != nil {
+		return 0, trace.Wrap(err)
+	}
+	id, err := strconv.ParseUint(idStr, 10, 64)
+	if err != nil || id == 0 {
+		return 0, trace.BadParameter("Invalid instance ID %q", idStr)
+	}
+	return id, nil
+}
+
+// GetTags gets all of the GCP instance's labels and tags.
 func (client *InstanceMetadataClient) GetTags(ctx context.Context) (map[string]string, error) {
 	// Get a bunch of info from instance metadata.
 	projectID, err := client.GetProjectID(ctx)
@@ -96,11 +107,7 @@ func (client *InstanceMetadataClient) GetTags(ctx context.Context) (map[string]s
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}
-	idStr, err := client.GetID(ctx)
-	if err != nil {
-		return nil, trace.Wrap(err)
-	}
-	id, err := strconv.ParseUint(idStr, 10, 64)
+	id, err := client.getNumericID(ctx)
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}

lib/cloud/imds/gcp/imds_test.go

@@ -58,16 +58,51 @@ func (m *mockInstanceGetter) GetInstanceTags(ctx context.Context, req *gcp.Insta
 func TestIsInstanceMetadataAvailable(t *testing.T) {
 	t.Parallel()
 
-	t.Run("not available", func(t *testing.T) {
-		client := &InstanceMetadataClient{
+	tests := []struct {
+		name        string
+		getMetadata metadataGetter
+		assert      require.BoolAssertionFunc
+	}{
+		{
+			name: "not available",
 			getMetadata: func(ctx context.Context, path string) (string, error) {
 				return "", trace.NotFound("")
 			},
-		}
-		require.False(t, client.IsAvailable(context.Background()))
-	})
+			assert: require.False,
+		},
+		{
+			name: "not on gcp",
+			getMetadata: func(ctx context.Context, path string) (string, error) {
+				return "non-numeric id", nil
+			},
+			assert: require.False,
+		},
+		{
+			name: "zero ID",
+			getMetadata: func(ctx context.Context, path string) (string, error) {
+				return "0", nil
+			},
+			assert: require.False,
+		},
+		{
+			name: "on mocked gcp",
+			getMetadata: func(ctx context.Context, path string) (string, error) {
+				return "12345678", nil
+			},
+			assert: require.True,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			client := &InstanceMetadataClient{
+				getMetadata: tc.getMetadata,
+			}
+			tc.assert(t, client.IsAvailable(context.Background()))
+		})
+	}
 
-	t.Run("on gcp", func(t *testing.T) {
+	t.Run("on real gcp", func(t *testing.T) {
 		if os.Getenv("TELEPORT_TEST_GCP") == "" {
 			t.Skip("not on gcp")
 		}

lib/service/service.go

@@ -955,8 +955,14 @@ func NewTeleport(cfg *servicecfg.Config) (*TeleportProcess, error) {
 	imClient := cfg.InstanceMetadataClient
 	if imClient == nil {
 		imClient, err = cloud.DiscoverInstanceMetadata(supervisor.ExitContext())
-		if err != nil && !trace.IsNotFound(err) {
-			return nil, trace.Wrap(err)
+		if err == nil {
+			cfg.Logger.InfoContext(supervisor.ExitContext(),
+				"Found an instance metadata service. Teleport will import labels from this cloud instance.",
+				"type", imClient.GetType())
+		} else if !trace.IsNotFound(err) {
+			cfg.Logger.ErrorContext(supervisor.ExitContext(), "Error looking for cloud instance metadata", "error", err)
+			// Keep going. Not being able to fetch labels isn't necessarily an error (e.g. the user doesn't need imported
+			// labels and hasn't configured their cloud instance for it).
 		}
 	}
 
@@ -965,23 +971,25 @@ func NewTeleport(cfg *servicecfg.Config) (*TeleportProcess, error) {
 		if err == nil {
 			cloudHostname = strings.ReplaceAll(cloudHostname, " ", "_")
 			if utils.IsValidHostname(cloudHostname) {
-				cfg.Logger.InfoContext(supervisor.ExitContext(), "Overriding hostname with value from cloud tag TeleportHostname.", "hostname", cloudHostname)
+				cfg.Logger.InfoContext(supervisor.ExitContext(), "Overriding hostname with value from cloud tag TeleportHostname", "hostname", cloudHostname)
 				cfg.Hostname = cloudHostname
 
 				// cloudHostname exists but is not a valid hostname.
 			} else if cloudHostname != "" {
-				cfg.Logger.InfoContext(supervisor.ExitContext(), "Found invalid hostname in cloud tag TeleportHostname.", "hostname", cloudHostname)
+				cfg.Logger.InfoContext(supervisor.ExitContext(), "Found invalid hostname in cloud tag TeleportHostname", "hostname", cloudHostname)
 			}
 		} else if !trace.IsNotFound(err) {
-			return nil, trace.Wrap(err)
+			cfg.Logger.ErrorContext(supervisor.ExitContext(), "Error looking for hostname tag", "error", err)
+			// Keep going.
 		}
 
 		cloudLabels, err = labels.NewCloudImporter(supervisor.ExitContext(), &labels.CloudConfig{
 			Client: imClient,
 			Clock:  cfg.Clock,
 		})
 		if err != nil {
-			return nil, trace.Wrap(err)
+			cfg.Logger.ErrorContext(supervisor.ExitContext(), "Cloud labels will not be imported", "error", err)
+			// Keep going.
 		}
 	}
 

lib/service/service_test.go

@@ -1620,3 +1620,112 @@ func TestDebugServiceStartSocket(t *testing.T) {
 	defer req.Body.Close()
 	require.Equal(t, http.StatusNotFound, req.StatusCode)
 }
+
+type mockInstanceMetadata struct {
+	hostname    string
+	hostnameErr error
+}
+
+func (m *mockInstanceMetadata) IsAvailable(ctx context.Context) bool {
+	return true
+}
+
+func (m *mockInstanceMetadata) GetTags(ctx context.Context) (map[string]string, error) {
+	return nil, nil
+}
+
+func (m *mockInstanceMetadata) GetHostname(ctx context.Context) (string, error) {
+	return m.hostname, m.hostnameErr
+}
+
+func (m *mockInstanceMetadata) GetType() types.InstanceMetadataType {
+	return "mock"
+}
+
+func (m *mockInstanceMetadata) GetID(ctx context.Context) (string, error) {
+	return "", nil
+}
+
+func TestInstanceMetadata(t *testing.T) {
+	t.Parallel()
+
+	newCfg := func() *servicecfg.Config {
+		cfg := servicecfg.MakeDefaultConfig()
+		cfg.Hostname = "default.example.com"
+		cfg.SetAuthServerAddress(utils.NetAddr{AddrNetwork: "tcp", Addr: "127.0.0.1:0"})
+		cfg.Auth.ListenAddr = utils.NetAddr{AddrNetwork: "tcp", Addr: "127.0.0.1:0"}
+		cfg.Proxy.Enabled = false
+		cfg.SSH.Enabled = false
+		cfg.CircuitBreakerConfig = breaker.NoopBreakerConfig()
+		return cfg
+	}
+
+	tests := []struct {
+		name              string
+		imClient          imds.Client
+		expectCloudLabels bool
+		expectedHostname  string
+	}{
+		{
+			name:              "no instance metadata",
+			imClient:          imds.NewDisabledIMDSClient(),
+			expectCloudLabels: false,
+			expectedHostname:  "default.example.com",
+		},
+		{
+			name: "instance metadata with valid hostname",
+			imClient: &mockInstanceMetadata{
+				hostname: "new.example.com",
+			},
+			expectCloudLabels: true,
+			expectedHostname:  "new.example.com",
+		},
+		{
+			name: "instance metadata with no hostname",
+			imClient: &mockInstanceMetadata{
+				hostnameErr: trace.NotFound(""),
+			},
+			expectCloudLabels: true,
+			expectedHostname:  "default.example.com",
+		},
+		{
+			name: "instance metadata with invalid hostname",
+			imClient: &mockInstanceMetadata{
+				hostname: ")7%#(*&@())",
+			},
+			expectCloudLabels: true,
+			expectedHostname:  "default.example.com",
+		},
+		{
+			name: "instance metadata with hostname error",
+			imClient: &mockInstanceMetadata{
+				hostnameErr: trace.Errorf(""),
+			},
+			expectCloudLabels: true,
+			expectedHostname:  "default.example.com",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := newCfg()
+			cfg.DataDir = t.TempDir()
+			cfg.Auth.StorageConfig.Params["path"] = t.TempDir()
+			cfg.InstanceMetadataClient = tc.imClient
+
+			process, err := NewTeleport(cfg)
+			require.NoError(t, err)
+			t.Cleanup(func() {
+				require.NoError(t, process.Close())
+			})
+
+			if tc.expectCloudLabels {
+				require.NotNil(t, process.cloudLabels)
+			} else {
+				require.Nil(t, process.cloudLabels)
+			}
+
+			require.Equal(t, tc.expectedHostname, cfg.Hostname)
+		})
+	}
+}