update to inject only the list of excluded resources.

pkg/kubeapiserver/admission/config.go

@@ -70,7 +70,7 @@ func (c *Config) New(proxyTransport *http.Transport, egressSelector *egressselec
 		cloudConfig,
 		discoveryRESTMapper,
 		quotainstall.NewQuotaConfigurationForAdmission(),
-		exclusion.NewFilter(),
+		exclusion.Excluded(),
 	)
 
 	admissionPostStartHook := func(context genericapiserver.PostStartHookContext) error {

pkg/kubeapiserver/admission/exclusion/filter.go

@@ -1,42 +0,0 @@
-/*
-Copyright 2024 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package exclusion
-
-import (
-	"k8s.io/apimachinery/pkg/runtime/schema"
-	"k8s.io/apimachinery/pkg/util/sets"
-	"k8s.io/apiserver/pkg/admission"
-	"k8s.io/apiserver/pkg/admission/resourcefilter"
-)
-
-// NewFilter creates a resource filter with the built-in exclusion list.
-func NewFilter() resourcefilter.Interface {
-	return &filter{excluded: sets.New[schema.GroupResource](excluded...)}
-}
-
-type filter struct {
-	excluded sets.Set[schema.GroupResource]
-}
-
-func (f *filter) ShouldHandle(a admission.Attributes) bool {
-	gvr := a.GetResource()
-	// ignore the version for the decision-making
-	// because putting different versions into different category
-	// is almost always a mistake.
-	gr := gvr.GroupResource()
-	return !f.excluded.Has(gr)
-}

pkg/kubeapiserver/admission/initializer.go

@@ -18,9 +18,9 @@ package admission
 
 import (
 	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/apiserver/pkg/admission/initializer"
-	"k8s.io/apiserver/pkg/admission/resourcefilter"
 	quota "k8s.io/apiserver/pkg/quota/v1"
 )
 
@@ -33,10 +33,10 @@ type WantsCloudConfig interface {
 
 // PluginInitializer is used for initialization of the Kubernetes specific admission plugins.
 type PluginInitializer struct {
-	cloudConfig        []byte
-	restMapper         meta.RESTMapper
-	quotaConfiguration quota.Configuration
-	resourceFilter     resourcefilter.Interface
+	cloudConfig                []byte
+	restMapper                 meta.RESTMapper
+	quotaConfiguration         quota.Configuration
+	excludedAdmissionResources []schema.GroupResource
 }
 
 var _ admission.PluginInitializer = &PluginInitializer{}
@@ -48,13 +48,13 @@ func NewPluginInitializer(
 	cloudConfig []byte,
 	restMapper meta.RESTMapper,
 	quotaConfiguration quota.Configuration,
-	resourceFilter resourcefilter.Interface,
+	excludedAdmissionResources []schema.GroupResource,
 ) *PluginInitializer {
 	return &PluginInitializer{
-		cloudConfig:        cloudConfig,
-		restMapper:         restMapper,
-		quotaConfiguration: quotaConfiguration,
-		resourceFilter:     resourceFilter,
+		cloudConfig:                cloudConfig,
+		restMapper:                 restMapper,
+		quotaConfiguration:         quotaConfiguration,
+		excludedAdmissionResources: excludedAdmissionResources,
 	}
 }
 
@@ -73,7 +73,7 @@ func (i *PluginInitializer) Initialize(plugin admission.Interface) {
 		wants.SetQuotaConfiguration(i.quotaConfiguration)
 	}
 
-	if wants, ok := plugin.(initializer.WantsResourceFilter); ok {
-		wants.SetResourceFilter(i.resourceFilter)
+	if wants, ok := plugin.(initializer.WantsExcludedAdmissionResources); ok {
+		wants.SetExcludedAdmissionResources(i.excludedAdmissionResources)
 	}
 }

staging/src/k8s.io/apiserver/pkg/admission/initializer/interfaces.go

@@ -18,8 +18,8 @@ package initializer
 
 import (
 	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apiserver/pkg/admission"
-	"k8s.io/apiserver/pkg/admission/resourcefilter"
 	"k8s.io/apiserver/pkg/authorization/authorizer"
 	"k8s.io/apiserver/pkg/cel/openapi/resolver"
 	quota "k8s.io/apiserver/pkg/quota/v1"
@@ -91,9 +91,9 @@ type WantsSchemaResolver interface {
 	admission.InitializationValidator
 }
 
-// WantsResourceFilter defines a function which sets the ResourceFilter for
-// an admission plugin that needs it.
-type WantsResourceFilter interface {
-	SetResourceFilter(filter resourcefilter.Interface)
+// WantsExcludedAdmissionResources defines a function which sets the ExcludedAdmissionResources
+// for an admission plugin that needs it.
+type WantsExcludedAdmissionResources interface {
+	SetExcludedAdmissionResources(excludedAdmissionResources []schema.GroupResource)
 	admission.InitializationValidator
 }

staging/src/k8s.io/apiserver/pkg/admission/plugin/policy/generic/plugin.go

@@ -21,12 +21,14 @@ import (
 	"errors"
 	"fmt"
 
+	admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
 	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/apiserver/pkg/admission/initializer"
 	"k8s.io/apiserver/pkg/admission/plugin/policy/matching"
-	"k8s.io/apiserver/pkg/admission/resourcefilter"
 	"k8s.io/apiserver/pkg/authorization/authorizer"
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/informers"
@@ -37,6 +39,15 @@ import (
 type sourceFactory[H any] func(informers.SharedInformerFactory, kubernetes.Interface, dynamic.Interface, meta.RESTMapper) Source[H]
 type dispatcherFactory[H any] func(authorizer.Authorizer, *matching.Matcher) Dispatcher[H]
 
+// admissionResources is the list of resources related to CEL-based admission
+// features.
+var admissionResources = []schema.GroupResource{
+	{Group: admissionregistrationv1.GroupName, Resource: "validatingadmissionpolicies"},
+	{Group: admissionregistrationv1.GroupName, Resource: "validatingadmissionpolicybindings"},
+	{Group: admissionregistrationv1.GroupName, Resource: "mutatingadmissionpolicies"},
+	{Group: admissionregistrationv1.GroupName, Resource: "mutatingadmissionpolicybindings"},
+}
+
 // AdmissionPolicyManager is an abstract admission plugin with all the
 // infrastructure to define Admit or Validate on-top.
 type Plugin[H any] struct {
@@ -49,14 +60,14 @@ type Plugin[H any] struct {
 	dispatcher Dispatcher[H]
 	matcher    *matching.Matcher
 
-	informerFactory informers.SharedInformerFactory
-	client          kubernetes.Interface
-	restMapper      meta.RESTMapper
-	dynamicClient   dynamic.Interface
-	resourceFilter  resourcefilter.Interface // optional
-	stopCh          <-chan struct{}
-	authorizer      authorizer.Authorizer
-	enabled         bool
+	informerFactory   informers.SharedInformerFactory
+	client            kubernetes.Interface
+	restMapper        meta.RESTMapper
+	dynamicClient     dynamic.Interface
+	excludedResources sets.Set[schema.GroupResource]
+	stopCh            <-chan struct{}
+	authorizer        authorizer.Authorizer
+	enabled           bool
 }
 
 var (
@@ -66,7 +77,7 @@ var (
 	_ initializer.WantsDynamicClient               = &Plugin[any]{}
 	_ initializer.WantsDrainedNotification         = &Plugin[any]{}
 	_ initializer.WantsAuthorizer                  = &Plugin[any]{}
-	_ initializer.WantsResourceFilter              = &Plugin[any]{}
+	_ initializer.WantsExcludedAdmissionResources  = &Plugin[any]{}
 	_ admission.InitializationValidator            = &Plugin[any]{}
 )
 
@@ -79,6 +90,9 @@ func NewPlugin[H any](
 		Handler:           handler,
 		sourceFactory:     sourceFactory,
 		dispatcherFactory: dispatcherFactory,
+
+		// always exclude admission/mutating policies and bindings
+		excludedResources: sets.New(admissionResources...),
 	}
 }
 
@@ -114,8 +128,8 @@ func (c *Plugin[H]) SetEnabled(enabled bool) {
 	c.enabled = enabled
 }
 
-func (c *Plugin[H]) SetResourceFilter(filter resourcefilter.Interface) {
-	c.resourceFilter = filter
+func (c *Plugin[H]) SetExcludedAdmissionResources(excludedResources []schema.GroupResource) {
+	c.excludedResources.Insert(excludedResources...)
 }
 
 // ValidateInitialization - once clientset and informer factory are provided, creates and starts the admission controller
@@ -184,7 +198,7 @@ func (c *Plugin[H]) Dispatch(
 ) (err error) {
 	if !c.enabled {
 		return nil
-	} else if isPolicyResource(a) || (c.resourceFilter != nil && !c.resourceFilter.ShouldHandle(a)) {
+	} else if c.shouldIgnoreResource(a) {
 		return nil
 	} else if !c.WaitForReady() {
 		return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
@@ -193,14 +207,9 @@ func (c *Plugin[H]) Dispatch(
 	return c.dispatcher.Dispatch(ctx, a, o, c.source.Hooks())
 }
 
-func isPolicyResource(attr admission.Attributes) bool {
-	gvk := attr.GetResource()
-	if gvk.Group == "admissionregistration.k8s.io" {
-		if gvk.Resource == "validatingadmissionpolicies" || gvk.Resource == "validatingadmissionpolicybindings" {
-			return true
-		} else if gvk.Resource == "mutatingadmissionpolicies" || gvk.Resource == "mutatingadmissionpolicybindings" {
-			return true
-		}
-	}
-	return false
+func (c *Plugin[H]) shouldIgnoreResource(attr admission.Attributes) bool {
+	gvr := attr.GetResource()
+	// exclusion decision ignores the version.
+	gr := gvr.GroupResource()
+	return c.excludedResources.Has(gr)
 }

staging/src/k8s.io/apiserver/pkg/admission/plugin/policy/validating/plugin.go

@@ -74,7 +74,7 @@ type Plugin struct {
 var _ admission.Interface = &Plugin{}
 var _ admission.ValidationInterface = &Plugin{}
 var _ initializer.WantsFeatures = &Plugin{}
-var _ initializer.WantsResourceFilter = &Plugin{}
+var _ initializer.WantsExcludedAdmissionResources = &Plugin{}
 
 func NewPlugin(_ io.Reader) *Plugin {
 	handler := admission.NewHandler(admission.Connect, admission.Create, admission.Delete, admission.Update)

staging/src/k8s.io/apiserver/pkg/admission/resourcefilter/interfaces.go

@@ -1,29 +0,0 @@
-/*
-Copyright 2024 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package resourcefilter
-
-import (
-	"k8s.io/apiserver/pkg/admission"
-)
-
-// Interface is a resource filter that takes an Attributes and
-// check if it should be handled or ignored by the admission plugin.
-type Interface interface {
-	// ShouldHandle returns true if the admission plugin should handle the request,
-	// considering the given Attributes, or false otherwise.
-	ShouldHandle(admission.Attributes) bool
-}