Allow CA dirs to be specified beyond /custom/ca/ (#5859)

Signed-off-by: Joel Smith <joelsmith@redhat.com>

CHANGELOG.md

@@ -59,6 +59,7 @@ To learn more about active deprecations, we recommend checking [GitHub Discussio
 ### New
 
 - TODO ([#XXX](https://github.com/kedacore/keda/issues/XXX))
+- **General**: Add --ca-dir flag to KEDA operator to specify directories with CA certificates for scalers to authenticate TLS connections (defaults to /custom/ca) ([#5860](https://github.com/kedacore/keda/issues/5860))
 - **General**: Declarative parsing of scaler config ([#5037](https://github.com/kedacore/keda/issues/5037)|[#5797](https://github.com/kedacore/keda/issues/5797))
 - **General**: Support for Kubernetes v1.30 ([#5828](https://github.com/kedacore/keda/issues/5828))
 

cmd/operator/main.go

@@ -85,6 +85,7 @@ func main() {
 	var k8sClusterDomain string
 	var enableCertRotation bool
 	var validatingWebhookName string
+	var caDirs []string
 	pflag.BoolVar(&enablePrometheusMetrics, "enable-prometheus-metrics", true, "Enable the prometheus metric of keda-operator.")
 	pflag.BoolVar(&enableOpenTelemetryMetrics, "enable-opentelemetry-metrics", false, "Enable the opentelemetry metric of keda-operator.")
 	pflag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the prometheus metric endpoint binds to.")
@@ -106,6 +107,7 @@ func main() {
 	pflag.StringVar(&k8sClusterDomain, "k8s-cluster-domain", "cluster.local", "Kubernetes cluster domain. Defaults to cluster.local")
 	pflag.BoolVar(&enableCertRotation, "enable-cert-rotation", false, "enable automatic generation and rotation of TLS certificates/keys")
 	pflag.StringVar(&validatingWebhookName, "validating-webhook-name", "keda-admission", "ValidatingWebhookConfiguration name. Defaults to keda-admission")
+	pflag.StringArrayVar(&caDirs, "ca-dir", []string{"/custom/ca"}, "Directory with CA certificates for scalers to authenticate TLS connections. Can be specified multiple times. Defaults to /custom/ca")
 	opts := zap.Options{}
 	opts.BindFlags(flag.CommandLine)
 	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
@@ -300,6 +302,8 @@ func main() {
 		close(certReady)
 	}
 
+	kedautil.SetCACertDirs(caDirs)
+
 	grpcServer := metricsservice.NewGrpcServer(&scaledHandler, metricsServiceAddr, certDir, certReady)
 	if err := mgr.Add(&grpcServer); err != nil {
 		setupLog.Error(err, "unable to set up Metrics Service gRPC server")

pkg/util/certificates.go

@@ -29,15 +29,23 @@ import (
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 )
 
-const customCAPath = "/custom/ca"
+const defaultCustomCAPath = "/custom/ca"
 
 var logger = logf.Log.WithName("certificates")
 
 var (
-	rootCAs     *x509.CertPool
-	rootCAsLock sync.Mutex
+	rootCAs       *x509.CertPool
+	rootCAsLock   sync.Mutex
+	customCAPaths = []string{defaultCustomCAPath}
 )
 
+// SetCACertDirs sets location(s) containing CA certificates which should be trusted for
+// all future calls to CreateTLSClientConfig
+func SetCACertDirs(caCertDirs []string) {
+	customCAPaths = caCertDirs
+	rootCAs = nil // force a reload on the next call to getRootCAs()
+}
+
 func getRootCAs() *x509.CertPool {
 	rootCAsLock.Lock()
 	defer rootCAsLock.Unlock()
@@ -56,37 +64,38 @@ func getRootCAs() *x509.CertPool {
 			logger.V(1).Info("system cert pool not available, using new cert pool instead")
 		}
 	}
-	if _, err := os.Stat(customCAPath); errors.Is(err, fs.ErrNotExist) {
-		logger.V(1).Info(fmt.Sprintf("the path %s doesn't exist, skipping custom CA registrations", customCAPath))
-		return rootCAs
-	}
-
-	files, err := os.ReadDir(customCAPath)
-	if err != nil {
-		logger.Error(err, fmt.Sprintf("unable to read %s", customCAPath))
-		return rootCAs
-	}
-
-	for _, file := range files {
-		filename := file.Name()
-		if file.IsDir() || strings.HasPrefix(filename, "..") {
-			logger.V(1).Info(fmt.Sprintf("%s isn't a valid certificate", filename))
-			continue // Skip directories and special files
+	for _, customCAPath := range customCAPaths {
+		if _, err := os.Stat(customCAPath); errors.Is(err, fs.ErrNotExist) {
+			logger.V(1).Info(fmt.Sprintf("the path %s doesn't exist, skipping custom CA registrations", customCAPath))
+			continue
 		}
 
-		filePath := filepath.Join(customCAPath, filename)
-		certs, err := os.ReadFile(filePath)
+		files, err := os.ReadDir(customCAPath)
 		if err != nil {
-			logger.Error(err, fmt.Sprintf("error reading %q", filename))
+			logger.Error(err, fmt.Sprintf("unable to read %s", customCAPath))
 			continue
 		}
 
-		if ok := rootCAs.AppendCertsFromPEM(certs); !ok {
-			logger.Error(fmt.Errorf("no certs appended"), "filename", filename)
-			continue
+		for _, file := range files {
+			filename := file.Name()
+			if file.IsDir() || strings.HasPrefix(filename, "..") {
+				logger.V(1).Info(fmt.Sprintf("%s isn't a valid certificate", filename))
+				continue // Skip directories and special files
+			}
+
+			filePath := filepath.Join(customCAPath, filename)
+			certs, err := os.ReadFile(filePath)
+			if err != nil {
+				logger.Error(err, fmt.Sprintf("error reading %q", filename))
+				continue
+			}
+
+			if ok := rootCAs.AppendCertsFromPEM(certs); !ok {
+				logger.Error(fmt.Errorf("no certs appended"), "filename", filename)
+				continue
+			}
+			logger.V(1).Info(fmt.Sprintf("the certificate %s has been added to the pool", filename))
 		}
-		logger.V(1).Info(fmt.Sprintf("the certificate %s has been added to the pool", filename))
 	}
-
 	return rootCAs
 }

pkg/util/certificates_test.go

@@ -34,19 +34,24 @@ import (
 )
 
 var (
-	caCrtPath      = path.Join(customCAPath, "ca.crt")
-	certCommonName = "test-cert"
+	certCommonName  = "test-cert"
+	certCommonName2 = "test-cert2"
 )
 
 func TestCustomCAsAreRegistered(t *testing.T) {
-	defer os.Remove(caCrtPath)
-	generateCA(t)
+	customCAPath, err := os.MkdirTemp("", "test-ca-certdir-")
+	require.NoErrorf(t, err, "error creating temporary certs dir - %s", err)
+	defer os.RemoveAll(customCAPath)
+
+	generateCA(t, certCommonName, customCAPath)
+
+	SetCACertDirs([]string{customCAPath})
 
 	rootCAs := getRootCAs()
 	//nolint:staticcheck // func (s *CertPool) Subjects was deprecated if s was returned by SystemCertPool, Subjects
 	subjects := rootCAs.Subjects()
 	var rdnSequence pkix.RDNSequence
-	_, err := asn1.Unmarshal(subjects[len(subjects)-1], &rdnSequence)
+	_, err = asn1.Unmarshal(subjects[len(subjects)-1], &rdnSequence)
 	if err != nil {
 		t.Fatal("could not unmarshal der formatted subject")
 	}
@@ -56,8 +61,41 @@ func TestCustomCAsAreRegistered(t *testing.T) {
 	assert.Equal(t, certCommonName, name.CommonName, "certificate not found")
 }
 
-func generateCA(t *testing.T) {
-	err := os.MkdirAll(customCAPath, os.ModePerm)
+func TestMultipleCustomCADirs(t *testing.T) {
+	customCAPath, err := os.MkdirTemp("", "test-ca-certdir-")
+	require.NoErrorf(t, err, "error creating temporary certs dir - %s", err)
+	defer os.RemoveAll(customCAPath)
+	customCAPath2, err := os.MkdirTemp("", "test-ca-certdir2-")
+	require.NoErrorf(t, err, "error creating temporary certs dir - %s", err)
+	defer os.RemoveAll(customCAPath2)
+
+	generateCA(t, certCommonName, customCAPath)
+	generateCA(t, certCommonName2, customCAPath2)
+	SetCACertDirs([]string{customCAPath, customCAPath2})
+
+	rootCAs := getRootCAs()
+	//nolint:staticcheck // func (s *CertPool) Subjects was deprecated if s was returned by SystemCertPool, Subjects
+	subjects := rootCAs.Subjects()
+	var rdnSequence pkix.RDNSequence
+	for i := 0; i < 2; i++ {
+		_, err = asn1.Unmarshal(subjects[len(subjects)-1-i], &rdnSequence)
+		if err != nil {
+			t.Fatal("could not unmarshal der formatted subject")
+		}
+		var name pkix.Name
+		name.FillFromRDNSequence(&rdnSequence)
+
+		if i == 1 {
+			assert.Equal(t, certCommonName, name.CommonName, "certificate not found")
+		} else {
+			assert.Equal(t, certCommonName2, name.CommonName, "certificate not found")
+		}
+	}
+}
+
+func generateCA(t *testing.T, cn, dir string) {
+	err := os.MkdirAll(dir, os.ModePerm)
+	caCrtPath := path.Join(dir, "ca.crt")
 	require.NoErrorf(t, err, "error generating the custom ca folder - %s", err)
 
 	ca := &x509.Certificate{
@@ -69,7 +107,7 @@ func generateCA(t *testing.T) {
 			Locality:      []string{"San Francisco"},
 			StreetAddress: []string{"Golden Gate Bridge"},
 			PostalCode:    []string{"94016"},
-			CommonName:    certCommonName,
+			CommonName:    cn,
 		},
 		NotBefore:             time.Now(),
 		NotAfter:              time.Now().AddDate(10, 0, 0),