feat: allow configuring min tls for grpc

CHANGELOG.md

@@ -68,6 +68,7 @@ Here is an overview of all new **experimental** features:
 
 ### Improvements
 
+- **General**: Allow configuring minimum TLS version for GRPC client via `KEDA_GRPC_MIN_TLS_VERSION` ([#6320](https://github.com/kedacore/keda/pull/6320))
 - TODO ([#XXX](https://github.com/kedacore/keda/issues/XXX))
 
 ### Fixes

pkg/common/tls/tls.go

@@ -0,0 +1,54 @@
+package tls
+
+import (
+	ctls "crypto/tls"
+	"fmt"
+	"os"
+)
+
+type tlsVersion string
+
+const (
+	TLS10 tlsVersion = "TLS10"
+	TLS11 tlsVersion = "TLS11"
+	TLS12 tlsVersion = "TLS12"
+	TLS13 tlsVersion = "TLS13"
+)
+
+type tlsEnvVariableName string
+
+const (
+	minHTTPTLSVersionEnv tlsEnvVariableName = "KEDA_HTTP_MIN_TLS_VERSION"
+	minGrpcTLSVersionEnv tlsEnvVariableName = "KEDA_GRPC_MIN_TLS_VERSION"
+)
+
+const (
+	defaultMinHTTPTLSVersion = TLS12
+	defaultMinGrpcTLSVersion = TLS13
+)
+
+func getMinTLSVersion(envKey tlsEnvVariableName, defaultVal tlsVersion) (uint16, error) {
+	version := string(defaultVal)
+	if val, ok := os.LookupEnv(string(envKey)); ok {
+		version = val
+	}
+	mapping := map[string]uint16{
+		string(TLS10): ctls.VersionTLS10,
+		string(TLS11): ctls.VersionTLS11,
+		string(TLS12): ctls.VersionTLS12,
+		string(TLS13): ctls.VersionTLS13,
+	}
+	if v, ok := mapping[version]; ok {
+		return v, nil
+	}
+	fallback := mapping[string(defaultVal)]
+	return fallback, fmt.Errorf("invalid TLS version: %s, using %s", version, defaultVal)
+}
+
+func GetMinHTTPTLSVersion() (uint16, error) {
+	return getMinTLSVersion(minHTTPTLSVersionEnv, defaultMinHTTPTLSVersion)
+}
+
+func GetMinGrpcTLSVersion() (uint16, error) {
+	return getMinTLSVersion(minGrpcTLSVersionEnv, defaultMinGrpcTLSVersion)
+}

pkg/common/tls/tls_test.go

@@ -0,0 +1,81 @@
+package tls
+
+import (
+	"crypto/tls"
+	"fmt"
+	"os"
+	"testing"
+)
+
+type minTLSVersionTestData struct {
+	name            string
+	envSet          bool
+	envValue        string
+	expectedVersion uint16
+	shouldError     bool
+}
+
+var minTLSVersionTestDatas = []minTLSVersionTestData{
+	{
+		name:            "Set to TLS10",
+		envSet:          true,
+		envValue:        "TLS10",
+		expectedVersion: tls.VersionTLS10,
+	},
+	{
+		name:            "Set to TLS11",
+		envSet:          true,
+		envValue:        "TLS11",
+		expectedVersion: tls.VersionTLS11,
+	},
+	{
+		name:            "Set to TLS12",
+		envSet:          true,
+		envValue:        "TLS12",
+		expectedVersion: tls.VersionTLS12,
+	},
+	{
+		name:            "Set to TLS13",
+		envSet:          true,
+		envValue:        "TLS13",
+		expectedVersion: tls.VersionTLS13,
+	},
+	{
+		name:   "No setting",
+		envSet: false,
+	},
+	{
+		name:        "Invalid settings",
+		envSet:      true,
+		envValue:    "TLS9",
+		shouldError: true,
+	},
+}
+
+func testResolveMinTLSVersion(t *testing.T, minVersionFunc func() (uint16, error), envName string, defaultVersion uint16) {
+	defer os.Unsetenv(envName)
+	for _, testData := range minTLSVersionTestDatas {
+		name := fmt.Sprintf("%s: %s", envName, testData.name)
+		t.Run(name, func(t *testing.T) {
+			os.Unsetenv(envName)
+			expectedVersion := defaultVersion
+			if testData.expectedVersion != 0 {
+				expectedVersion = testData.expectedVersion
+			}
+			if testData.envSet {
+				os.Setenv(envName, testData.envValue)
+			}
+			minVersion, err := minVersionFunc()
+			if testData.shouldError && err == nil {
+				t.Error("Expected error but got none")
+			}
+			if expectedVersion != minVersion {
+				t.Error("Failed to resolve minTLSVersion correctly", "wants", testData.expectedVersion, "got", minVersion)
+			}
+		})
+	}
+}
+func TestResolveMinTLSVersion(t *testing.T) {
+	testResolveMinTLSVersion(t, GetMinHTTPTLSVersion, "KEDA_HTTP_MIN_TLS_VERSION", tls.VersionTLS12)
+	testResolveMinTLSVersion(t, GetMinGrpcTLSVersion, "KEDA_GRPC_MIN_TLS_VERSION", tls.VersionTLS13)
+}

pkg/metricsservice/utils/tls.go

@@ -24,6 +24,9 @@ import (
 	"path"
 
 	"google.golang.org/grpc/credentials"
+	ctrl "sigs.k8s.io/controller-runtime"
+
+	kedatls "github.com/kedacore/keda/v2/pkg/common/tls"
 )
 
 // LoadGrpcTLSCredentials reads the certificate from the given path and returns TLS transport credentials
@@ -50,8 +53,12 @@ func LoadGrpcTLSCredentials(certDir string, server bool) (credentials.TransportC
 	}
 
 	// Create the credentials and return it
+	minTLSVersion, err := kedatls.GetMinGrpcTLSVersion()
+	if err != nil {
+		ctrl.Log.WithName("grpc_tls_setup").Info(err.Error())
+	}
 	config := &tls.Config{
-		MinVersion:   tls.VersionTLS13,
+		MinVersion:   minTLSVersion,
 		Certificates: []tls.Certificate{cert},
 	}
 	if server {

pkg/util/tls_config.go

@@ -21,10 +21,11 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
-	"os"
 
 	"github.com/youmark/pkcs8"
 	ctrl "sigs.k8s.io/controller-runtime"
+
+	kedatls "github.com/kedacore/keda/v2/pkg/common/tls"
 )
 
 var minTLSVersion uint16
@@ -89,24 +90,7 @@ func GetMinTLSVersion() uint16 {
 }
 
 func initMinTLSVersion() (uint16, error) {
-	version, _ := os.LookupEnv("KEDA_HTTP_MIN_TLS_VERSION")
-
-	switch version {
-	case "":
-		minTLSVersion = tls.VersionTLS12
-	case "TLS10":
-		minTLSVersion = tls.VersionTLS10
-	case "TLS11":
-		minTLSVersion = tls.VersionTLS11
-	case "TLS12":
-		minTLSVersion = tls.VersionTLS12
-	case "TLS13":
-		minTLSVersion = tls.VersionTLS13
-	default:
-		return tls.VersionTLS12, fmt.Errorf("%s is not a valid value, using `TLS12`. Allowed values are: `TLS13`,`TLS12`,`TLS11`,`TLS10`", version)
-	}
-
-	return minTLSVersion, nil
+	return kedatls.GetMinHTTPTLSVersion()
 }
 
 func decryptClientKey(clientKey, clientKeyPassword string) ([]byte, error) {

pkg/util/tls_config_test.go

@@ -17,9 +17,7 @@ limitations under the License.
 package util
 
 import (
-	"crypto/tls"
 	"crypto/x509"
-	"os"
 	"strings"
 	"testing"
 )
@@ -252,51 +250,3 @@ func TestNewTLSConfig_WithPassword(t *testing.T) {
 		})
 	}
 }
-
-type minTLSVersionTestData struct {
-	envSet          bool
-	envValue        string
-	expectedVersion uint16
-}
-
-var minTLSVersionTestDatas = []minTLSVersionTestData{
-	{
-		envSet:          true,
-		envValue:        "TLS10",
-		expectedVersion: tls.VersionTLS10,
-	},
-	{
-		envSet:          true,
-		envValue:        "TLS11",
-		expectedVersion: tls.VersionTLS11,
-	},
-	{
-		envSet:          true,
-		envValue:        "TLS12",
-		expectedVersion: tls.VersionTLS12,
-	},
-	{
-		envSet:          true,
-		envValue:        "TLS13",
-		expectedVersion: tls.VersionTLS13,
-	},
-	{
-		envSet:          false,
-		expectedVersion: tls.VersionTLS12,
-	},
-}
-
-func TestResolveMinTLSVersion(t *testing.T) {
-	defer os.Unsetenv("KEDA_HTTP_MIN_TLS_VERSION")
-	for _, testData := range minTLSVersionTestDatas {
-		os.Unsetenv("KEDA_HTTP_MIN_TLS_VERSION")
-		if testData.envSet {
-			os.Setenv("KEDA_HTTP_MIN_TLS_VERSION", testData.envValue)
-		}
-		minVersion, _ := initMinTLSVersion()
-
-		if testData.expectedVersion != minVersion {
-			t.Error("Failed to resolve minTLSVersion correctly", "wants", testData.expectedVersion, "got", minVersion)
-		}
-	}
-}