Replace kube-rbac-proxy with controller-runtime metrics authentication/authorization

This commit removes the use of the kube-rbac-proxy image and replaces it with metrics authentication/authorization provided by controller-runtime. The kube-rbac-proxy image is deprecated and will no longer be maintained, which introduces risks to production environments. For more details, see: kubernetes-sigs/kubebuilder#3907

Key changes:
- Updated  to configure metrics server options with secure authentication/authorization using controller-runtime filters.
- Added support for disabling HTTP/2 by default to mitigate vulnerabilities (e.g., HTTP/2 Stream Cancellation CVE).
- Changed the default metrics endpoint to HTTPS (port 8443) and removed the kube-rbac-proxy container from deployment configurations.
- Updated RBAC files to include metrics-specific roles and bindings, ensuring secure access to metrics.

This aligns with best practices for security and simplifies the metrics setup by leveraging built-in capabilities of controller-runtime.

Author: Camila M

cmd/manager/main.go

@@ -18,11 +18,13 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	"flag"
 	"fmt"
 	"net/http"
 	"os"
 	"path/filepath"
+	"sigs.k8s.io/controller-runtime/pkg/metrics/filters"
 	"strings"
 	"time"
 
@@ -89,6 +91,9 @@ func podNamespace() string {
 func main() {
 	var (
 		metricsAddr               string
+		secureMetrics             bool
+		tlsOpts                   []func(*tls.Config)
+		enableHTTP2               bool
 		enableLeaderElection      bool
 		probeAddr                 string
 		cachePath                 string
@@ -97,7 +102,11 @@ func main() {
 		caCertDir                 string
 		globalPullSecret          string
 	)
-	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
+	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8443", "The address the metric endpoint binds to.")
+	flag.BoolVar(&secureMetrics, "metrics-secure", true,
+		"If set, the metrics endpoint is served securely via HTTPS. Use --metrics-secure=false to use HTTP instead.")
+	flag.BoolVar(&enableHTTP2, "enable-http2", false,
+		"If set, HTTP/2 will be enabled for the metrics and webhook servers")
 	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
 	flag.StringVar(&caCertDir, "ca-certs-dir", "", "The directory of TLS certificate to use for verifying HTTPS connections to the Catalogd and docker-registry web servers.")
 	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
@@ -161,9 +170,39 @@ func main() {
 			},
 		}
 	}
+
+	// if the enable-http2 flag is false (the default), http/2 should be disabled
+	// due to its vulnerabilities. More specifically, disabling http/2 will
+	// prevent from being vulnerable to the HTTP/2 Stream Cancellation and
+	// Rapid Reset CVEs. For more information see:
+	// - https://github.com/advisories/GHSA-qppj-fm5r-hxr3
+	// - https://github.com/advisories/GHSA-4374-p667-p6c8
+	disableHTTP2 := func(c *tls.Config) {
+		setupLog.Info("disabling http/2")
+		c.NextProtos = []string{"http/1.1"}
+	}
+
+	if !enableHTTP2 {
+		tlsOpts = append(tlsOpts, disableHTTP2)
+	}
+
+	metricsServerOptions := server.Options{
+		BindAddress:   metricsAddr,
+		SecureServing: secureMetrics,
+		TLSOpts:       tlsOpts,
+	}
+
+	if secureMetrics {
+		// FilterProvider is used to protect the metrics endpoint with authn/authz.
+		// These configurations ensure that only authorized users and service accounts
+		// can access the metrics endpoint. The RBAC are configured in 'config/rbac/kustomization.yaml'. More info:
+		// https://pkg.go.dev/sigs.k8s.io/[email protected]/pkg/metrics/filters#WithAuthenticationAndAuthorization
+		metricsServerOptions.FilterProvider = filters.WithAuthenticationAndAuthorization
+	}
+
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
 		Scheme:                 scheme.Scheme,
-		Metrics:                server.Options{BindAddress: metricsAddr},
+		Metrics:                metricsServerOptions,
 		HealthProbeBindAddress: probeAddr,
 		LeaderElection:         enableLeaderElection,
 		LeaderElectionID:       "9c4404e7.operatorframework.io",

config/base/manager/manager.yaml

@@ -52,7 +52,7 @@ spec:
         - /manager
         args:
         - "--health-probe-bind-address=:8081"
-        - "--metrics-bind-address=127.0.0.1:8080"
+        - "--metrics-bind-address=127.0.0.1:8443"
         - "--leader-elect"
         image: controller:latest
         imagePullPolicy: IfNotPresent
@@ -84,27 +84,6 @@ spec:
             cpu: 10m
             memory: 64Mi
         terminationMessagePolicy: FallbackToLogsOnError
-      - name: kube-rbac-proxy
-        securityContext:
-          allowPrivilegeEscalation: false
-          capabilities:
-            drop:
-              - "ALL"
-        image: gcr.io/kubebuilder/kube-rbac-proxy:v0.15.0
-        args:
-        - --secure-listen-address=0.0.0.0:8443
-        - --http2-disable
-        - --upstream=http://127.0.0.1:8080/
-        - --logtostderr=true
-        ports:
-        - containerPort: 8443
-          protocol: TCP
-          name: https
-        resources:
-          requests:
-            cpu: 5m
-            memory: 64Mi
-        terminationMessagePolicy: FallbackToLogsOnError
       serviceAccountName: operator-controller-controller-manager
       terminationGracePeriodSeconds: 10
       volumes:

config/base/rbac/auth_proxy_role.yaml

@@ -17,10 +17,12 @@ resources:
 - extension_editor_role.yaml
 - extension_viewer_role.yaml
 
-# Comment the following 4 lines if you want to disable
-# the auth proxy (https://github.com/brancz/kube-rbac-proxy)
-# which protects your /metrics endpoint.
-- auth_proxy_service.yaml
-- auth_proxy_role.yaml
-- auth_proxy_role_binding.yaml
-- auth_proxy_client_clusterrole.yaml
+# The following RBAC configurations are used to protect
+# the metrics endpoint with authn/authz. These configurations
+# ensure that only authorized users and service accounts
+# can access the metrics endpoint. Comment the following
+# permissions if you want to disable this protection.
+# More info: https://book.kubebuilder.io/reference/metrics.html
+- metrics_auth_role.yaml
+- metrics_auth_role_binding.yaml
+- metrics_reader_role.yaml

config/base/rbac/auth_proxy_service.yaml

@@ -0,0 +1,17 @@
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: metrics-auth-role
+rules:
+  - apiGroups:
+      - authentication.k8s.io
+    resources:
+      - tokenreviews
+    verbs:
+      - create
+  - apiGroups:
+      - authorization.k8s.io
+    resources:
+      - subjectaccessreviews
+    verbs:
+      - create

config/base/rbac/kustomization.yaml

@@ -1,12 +1,12 @@
 apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRoleBinding
 metadata:
-  name: proxy-rolebinding
+  name: metrics-auth-rolebinding
 roleRef:
   apiGroup: rbac.authorization.k8s.io
   kind: ClusterRole
-  name: proxy-role
+  name: metrics-auth-role
 subjects:
-- kind: ServiceAccount
-  name: controller-manager
-  namespace: system
+  - kind: ServiceAccount
+    name: controller-manager
+    namespace: system

config/base/rbac/metrics_auth_role.yaml

@@ -7,7 +7,6 @@ spec:
   template:
     spec:
       containers:
-      - name: kube-rbac-proxy
       - name: manager
         env:
         - name: GOCOVERDIR

config/base/rbac/auth_proxy_role_binding.yaml renamed to config/base/rbac/metrics_auth_role_binding.yaml

@@ -7,7 +7,6 @@ spec:
   template:
     spec:
       containers:
-      - name: kube-rbac-proxy
       - name: manager
         volumeMounts:
         - name: e2e-registries-conf