Disable HTTP/2

Signed-off-by: Marc Sluiter <[email protected]>

api/v1alpha1/selfnoderemediationconfig_webhook.go

@@ -18,8 +18,6 @@ package v1alpha1
 
 import (
 	"fmt"
-	"os"
-	"path/filepath"
 	"time"
 
 	v1 "k8s.io/api/core/v1"
@@ -30,12 +28,6 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/webhook"
 )
 
-const (
-	webhookCertDir  = "/apiserver.local.config/certificates"
-	webhookCertName = "apiserver.crt"
-	webhookKeyName  = "apiserver.key"
-)
-
 // fields names
 const (
 	peerApiServerTimeout = "PeerApiServerTimeout"
@@ -66,25 +58,6 @@ type field struct {
 var selfNodeRemediationConfigLog = logf.Log.WithName("selfnoderemediationconfig-resource")
 
 func (r *SelfNodeRemediationConfig) SetupWebhookWithManager(mgr ctrl.Manager) error {
-
-	// check if OLM injected certs
-	certs := []string{filepath.Join(webhookCertDir, webhookCertName), filepath.Join(webhookCertDir, webhookKeyName)}
-	certsInjected := true
-	for _, fname := range certs {
-		if _, err := os.Stat(fname); err != nil {
-			certsInjected = false
-			break
-		}
-	}
-	if certsInjected {
-		server := mgr.GetWebhookServer()
-		server.CertDir = webhookCertDir
-		server.CertName = webhookCertName
-		server.KeyName = webhookKeyName
-	} else {
-		selfNodeRemediationConfigLog.Info("OLM injected certs for webhooks not found")
-	}
-
 	return ctrl.NewWebhookManagedBy(mgr).
 		For(r).
 		Complete()

main.go

@@ -17,8 +17,10 @@ limitations under the License.
 package main
 
 import (
+	"crypto/tls"
 	"flag"
 	"os"
+	"path/filepath"
 	"strconv"
 	"time"
 
@@ -56,6 +58,10 @@ import (
 
 const (
 	nodeNameEnvVar = "MY_NODE_NAME"
+
+	WebhookCertDir  = "/apiserver.local.config/certificates"
+	WebhookCertName = "apiserver.crt"
+	WebhookKeyName  = "apiserver.key"
 )
 
 var (
@@ -75,12 +81,14 @@ func main() {
 	var metricsAddr string
 	var enableLeaderElection bool
 	var probeAddr string
+	var enableHTTP2 bool
 	var isManager bool
 	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
 	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
 	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
 		"Enable leader election for controller manager. "+
 			"Enabling this will ensure there is only one active controller manager.")
+	flag.BoolVar(&enableHTTP2, "enable-http2", false, "If HTTP/2 should be enabled for the metrics and webhook servers.")
 	flag.BoolVar(&isManager, "is-manager", false,
 		"Used to differentiate between the self node remediation agents that runs in a daemonset to the 'manager' that only"+
 			"reconciles the config CRD and installs the DS")
@@ -94,7 +102,9 @@ func main() {
 	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
 
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
-		Scheme:                 scheme,
+		Scheme: scheme,
+		// HEADS UP: once controller runtime is updated and this changes to metrics.Options{},
+		// and in case you configure TLS / SecureServing, disable HTTP/2 in it for mitigating related CVEs!
 		MetricsBindAddress:     metricsAddr,
 		Port:                   9443,
 		HealthProbeBindAddress: probeAddr,
@@ -107,7 +117,7 @@ func main() {
 	}
 
 	if isManager {
-		initSelfNodeRemediationManager(mgr)
+		initSelfNodeRemediationManager(mgr, enableHTTP2)
 	} else {
 		initSelfNodeRemediationAgent(mgr)
 	}
@@ -130,9 +140,11 @@ func main() {
 	}
 }
 
-func initSelfNodeRemediationManager(mgr manager.Manager) {
+func initSelfNodeRemediationManager(mgr manager.Manager, enableHTTP2 bool) {
 	setupLog.Info("Starting as a manager that installs the daemonset")
 
+	configureWebhookServer(mgr, enableHTTP2)
+
 	if err := utils.InitOutOfServiceTaintSupportedFlag(mgr.GetConfig()); err != nil {
 		setupLog.Error(err, "unable to verify out of service taint support. out of service taint isn't supported")
 	}
@@ -353,3 +365,38 @@ func initSelfNodeRemediationAgent(mgr manager.Manager) {
 		os.Exit(1)
 	}
 }
+
+func configureWebhookServer(mgr ctrl.Manager, enableHTTP2 bool) {
+
+	server := mgr.GetWebhookServer()
+
+	// check for OLM injected certs
+	certs := []string{filepath.Join(WebhookCertDir, WebhookCertName), filepath.Join(WebhookCertDir, WebhookKeyName)}
+	certsInjected := true
+	for _, fname := range certs {
+		if _, err := os.Stat(fname); err != nil {
+			certsInjected = false
+			break
+		}
+	}
+	if certsInjected {
+		server.CertDir = WebhookCertDir
+		server.CertName = WebhookCertName
+		server.KeyName = WebhookKeyName
+	} else {
+		setupLog.Info("OLM injected certs for webhooks not found")
+	}
+
+	// disable http/2 for mitigating relevant CVEs
+	if !enableHTTP2 {
+		server.TLSOpts = append(server.TLSOpts,
+			func(c *tls.Config) {
+				c.NextProtos = []string{"http/1.1"}
+			},
+		)
+		setupLog.Info("HTTP/2 for webhooks disabled")
+	} else {
+		setupLog.Info("HTTP/2 for webhooks enabled")
+	}
+
+}