rebase: update K8s packages to v0.32.1

Update K8s packages in go.mod to v0.32.1

Signed-off-by: Praveen M <m.praveen@ibm.com>

vendor/k8s.io/apiserver/pkg/admission/config.go

@@ -63,7 +63,7 @@ func ReadAdmissionConfiguration(pluginNames []string, configFilePath string, con
 	if err != nil {
 		return nil, fmt.Errorf("unable to read admission control configuration from %q [%v]", configFilePath, err)
 	}
-	codecs := serializer.NewCodecFactory(configScheme)
+	codecs := serializer.NewCodecFactory(configScheme, serializer.EnableStrict)
 	decoder := codecs.UniversalDecoder()
 	decodedObj, err := runtime.Decode(decoder, data)
 	// we were able to decode the file successfully

vendor/k8s.io/apiserver/pkg/admission/metrics/metrics.go

@@ -207,7 +207,7 @@ func newAdmissionMetrics() *AdmissionMetrics {
 			Namespace:      namespace,
 			Subsystem:      subsystem,
 			Name:           "webhook_fail_open_count",
-			Help:           "Admission webhook fail open count, identified by name and broken out for each admission type (validating or mutating).",
+			Help:           "Admission webhook fail open count, identified by name and broken out for each admission type (validating or admit).",
 			StabilityLevel: metrics.ALPHA,
 		},
 		[]string{"name", "type"})
@@ -217,7 +217,7 @@ func newAdmissionMetrics() *AdmissionMetrics {
 			Namespace:      namespace,
 			Subsystem:      subsystem,
 			Name:           "webhook_request_total",
-			Help:           "Admission webhook request total, identified by name and broken out for each admission type (validating or mutating) and operation. Additional labels specify whether the request was rejected or not and an HTTP status code. Codes greater than 600 are truncated to 600, to keep the metrics cardinality bounded.",
+			Help:           "Admission webhook request total, identified by name and broken out for each admission type (validating or admit) and operation. Additional labels specify whether the request was rejected or not and an HTTP status code. Codes greater than 600 are truncated to 600, to keep the metrics cardinality bounded.",
 			StabilityLevel: metrics.ALPHA,
 		},
 		[]string{"name", "type", "operation", "code", "rejected"})

vendor/k8s.io/apiserver/pkg/admission/plugin/authorizer/caching_authorizer.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package validating
+package authorizer
 
 import (
 	"context"
@@ -39,7 +39,10 @@ type cachingAuthorizer struct {
 	decisions  map[string]authzResult
 }
 
-func newCachingAuthorizer(in authorizer.Authorizer) authorizer.Authorizer {
+// NewCachingAuthorizer returns an authorizer that caches decisions for the duration
+// of the authorizers use.  Intended to be used for short-lived operations such as
+// the handling of a request in the admission chain, and then discarded.
+func NewCachingAuthorizer(in authorizer.Authorizer) authorizer.Authorizer {
 	return &cachingAuthorizer{
 		authorizer: in,
 		decisions:  make(map[string]authzResult),

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/activation.go

@@ -0,0 +1,190 @@
+/*
+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 cel
+
+import (
+	"context"
+	"fmt"
+	"github.com/google/cel-go/interpreter"
+	"math"
+	"time"
+
+	admissionv1 "k8s.io/api/admission/v1"
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apiserver/pkg/admission"
+	"k8s.io/apiserver/pkg/cel"
+	"k8s.io/apiserver/pkg/cel/library"
+)
+
+// newActivation creates an activation for CEL admission plugins from the given request, admission chain and
+// variable binding information.
+func newActivation(compositionCtx CompositionContext, versionedAttr *admission.VersionedAttributes, request *admissionv1.AdmissionRequest, inputs OptionalVariableBindings, namespace *v1.Namespace) (*evaluationActivation, error) {
+	oldObjectVal, err := objectToResolveVal(versionedAttr.VersionedOldObject)
+	if err != nil {
+		return nil, fmt.Errorf("failed to prepare oldObject variable for evaluation: %w", err)
+	}
+	objectVal, err := objectToResolveVal(versionedAttr.VersionedObject)
+	if err != nil {
+		return nil, fmt.Errorf("failed to prepare object variable for evaluation: %w", err)
+	}
+	var paramsVal, authorizerVal, requestResourceAuthorizerVal any
+	if inputs.VersionedParams != nil {
+		paramsVal, err = objectToResolveVal(inputs.VersionedParams)
+		if err != nil {
+			return nil, fmt.Errorf("failed to prepare params variable for evaluation: %w", err)
+		}
+	}
+
+	if inputs.Authorizer != nil {
+		authorizerVal = library.NewAuthorizerVal(versionedAttr.GetUserInfo(), inputs.Authorizer)
+		requestResourceAuthorizerVal = library.NewResourceAuthorizerVal(versionedAttr.GetUserInfo(), inputs.Authorizer, versionedAttr)
+	}
+
+	requestVal, err := convertObjectToUnstructured(request)
+	if err != nil {
+		return nil, fmt.Errorf("failed to prepare request variable for evaluation: %w", err)
+	}
+	namespaceVal, err := objectToResolveVal(namespace)
+	if err != nil {
+		return nil, fmt.Errorf("failed to prepare namespace variable for evaluation: %w", err)
+	}
+	va := &evaluationActivation{
+		object:                    objectVal,
+		oldObject:                 oldObjectVal,
+		params:                    paramsVal,
+		request:                   requestVal.Object,
+		namespace:                 namespaceVal,
+		authorizer:                authorizerVal,
+		requestResourceAuthorizer: requestResourceAuthorizerVal,
+	}
+
+	// composition is an optional feature that only applies for ValidatingAdmissionPolicy and MutatingAdmissionPolicy.
+	if compositionCtx != nil {
+		va.variables = compositionCtx.Variables(va)
+	}
+	return va, nil
+}
+
+type evaluationActivation struct {
+	object, oldObject, params, request, namespace, authorizer, requestResourceAuthorizer, variables interface{}
+}
+
+// ResolveName returns a value from the activation by qualified name, or false if the name
+// could not be found.
+func (a *evaluationActivation) ResolveName(name string) (interface{}, bool) {
+	switch name {
+	case ObjectVarName:
+		return a.object, true
+	case OldObjectVarName:
+		return a.oldObject, true
+	case ParamsVarName:
+		return a.params, true // params may be null
+	case RequestVarName:
+		return a.request, true
+	case NamespaceVarName:
+		return a.namespace, true
+	case AuthorizerVarName:
+		return a.authorizer, a.authorizer != nil
+	case RequestResourceAuthorizerVarName:
+		return a.requestResourceAuthorizer, a.requestResourceAuthorizer != nil
+	case VariableVarName: // variables always present
+		return a.variables, true
+	default:
+		return nil, false
+	}
+}
+
+// Parent returns the parent of the current activation, may be nil.
+// If non-nil, the parent will be searched during resolve calls.
+func (a *evaluationActivation) Parent() interpreter.Activation {
+	return nil
+}
+
+// Evaluate runs a compiled CEL admission plugin expression using the provided activation and CEL
+// runtime cost budget.
+func (a *evaluationActivation) Evaluate(ctx context.Context, compositionCtx CompositionContext, compilationResult CompilationResult, remainingBudget int64) (EvaluationResult, int64, error) {
+	var evaluation = EvaluationResult{}
+	if compilationResult.ExpressionAccessor == nil { // in case of placeholder
+		return evaluation, remainingBudget, nil
+	}
+
+	evaluation.ExpressionAccessor = compilationResult.ExpressionAccessor
+	if compilationResult.Error != nil {
+		evaluation.Error = &cel.Error{
+			Type:   cel.ErrorTypeInvalid,
+			Detail: fmt.Sprintf("compilation error: %v", compilationResult.Error),
+			Cause:  compilationResult.Error,
+		}
+		return evaluation, remainingBudget, nil
+	}
+	if compilationResult.Program == nil {
+		evaluation.Error = &cel.Error{
+			Type:   cel.ErrorTypeInternal,
+			Detail: "unexpected internal error compiling expression",
+		}
+		return evaluation, remainingBudget, nil
+	}
+	t1 := time.Now()
+	evalResult, evalDetails, err := compilationResult.Program.ContextEval(ctx, a)
+	// budget may be spent due to lazy evaluation of composited variables
+	if compositionCtx != nil {
+		compositionCost := compositionCtx.GetAndResetCost()
+		if compositionCost > remainingBudget {
+			return evaluation, -1, &cel.Error{
+				Type:   cel.ErrorTypeInvalid,
+				Detail: "validation failed due to running out of cost budget, no further validation rules will be run",
+				Cause:  cel.ErrOutOfBudget,
+			}
+		}
+		remainingBudget -= compositionCost
+	}
+	elapsed := time.Since(t1)
+	evaluation.Elapsed = elapsed
+	if evalDetails == nil {
+		return evaluation, -1, &cel.Error{
+			Type:   cel.ErrorTypeInternal,
+			Detail: fmt.Sprintf("runtime cost could not be calculated for expression: %v, no further expression will be run", compilationResult.ExpressionAccessor.GetExpression()),
+		}
+	} else {
+		rtCost := evalDetails.ActualCost()
+		if rtCost == nil {
+			return evaluation, -1, &cel.Error{
+				Type:   cel.ErrorTypeInvalid,
+				Detail: fmt.Sprintf("runtime cost could not be calculated for expression: %v, no further expression will be run", compilationResult.ExpressionAccessor.GetExpression()),
+				Cause:  cel.ErrOutOfBudget,
+			}
+		} else {
+			if *rtCost > math.MaxInt64 || int64(*rtCost) > remainingBudget {
+				return evaluation, -1, &cel.Error{
+					Type:   cel.ErrorTypeInvalid,
+					Detail: "validation failed due to running out of cost budget, no further validation rules will be run",
+					Cause:  cel.ErrOutOfBudget,
+				}
+			}
+			remainingBudget -= int64(*rtCost)
+		}
+	}
+	if err != nil {
+		evaluation.Error = &cel.Error{
+			Type:   cel.ErrorTypeInvalid,
+			Detail: fmt.Sprintf("expression '%v' resulted in error: %v", compilationResult.ExpressionAccessor.GetExpression(), err),
+		}
+	} else {
+		evaluation.EvalResult = evalResult
+	}
+	return evaluation, remainingBudget, nil
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/compile.go

@@ -24,8 +24,10 @@ import (
 	"k8s.io/apimachinery/pkg/util/version"
 	celconfig "k8s.io/apiserver/pkg/apis/cel"
 	apiservercel "k8s.io/apiserver/pkg/cel"
+	"k8s.io/apiserver/pkg/cel/common"
 	"k8s.io/apiserver/pkg/cel/environment"
 	"k8s.io/apiserver/pkg/cel/library"
+	"k8s.io/apiserver/pkg/cel/mutation"
 )
 
 const (
@@ -186,7 +188,7 @@ func (c compiler) CompileCELExpression(expressionAccessor ExpressionAccessor, op
 	found := false
 	returnTypes := expressionAccessor.ReturnTypes()
 	for _, returnType := range returnTypes {
-		if ast.OutputType() == returnType || cel.AnyType == returnType {
+		if ast.OutputType().IsExactType(returnType) || cel.AnyType.IsExactType(returnType) {
 			found = true
 			break
 		}
@@ -194,9 +196,9 @@ func (c compiler) CompileCELExpression(expressionAccessor ExpressionAccessor, op
 	if !found {
 		var reason string
 		if len(returnTypes) == 1 {
-			reason = fmt.Sprintf("must evaluate to %v", returnTypes[0].String())
+			reason = fmt.Sprintf("must evaluate to %v but got %v", returnTypes[0].String(), ast.OutputType().String())
 		} else {
-			reason = fmt.Sprintf("must evaluate to one of %v", returnTypes)
+			reason = fmt.Sprintf("must evaluate to one of %v but got %v", returnTypes, ast.OutputType().String())
 		}
 
 		return resultError(reason, apiservercel.ErrorTypeInvalid, nil)
@@ -226,46 +228,78 @@ func mustBuildEnvs(baseEnv *environment.EnvSet) variableDeclEnvs {
 	envs := make(variableDeclEnvs, 8) // since the number of variable combinations is small, pre-build a environment for each
 	for _, hasParams := range []bool{false, true} {
 		for _, hasAuthorizer := range []bool{false, true} {
+			var err error
 			for _, strictCost := range []bool{false, true} {
-				var envOpts []cel.EnvOption
-				if hasParams {
-					envOpts = append(envOpts, cel.Variable(ParamsVarName, cel.DynType))
-				}
-				if hasAuthorizer {
-					envOpts = append(envOpts,
-						cel.Variable(AuthorizerVarName, library.AuthorizerType),
-						cel.Variable(RequestResourceAuthorizerVarName, library.ResourceCheckType))
-				}
-				envOpts = append(envOpts,
-					cel.Variable(ObjectVarName, cel.DynType),
-					cel.Variable(OldObjectVarName, cel.DynType),
-					cel.Variable(NamespaceVarName, namespaceType.CelType()),
-					cel.Variable(RequestVarName, requestType.CelType()))
-
-				extended, err := baseEnv.Extend(
-					environment.VersionedOptions{
-						// Feature epoch was actually 1.26, but we artificially set it to 1.0 because these
-						// options should always be present.
-						IntroducedVersion: version.MajorMinor(1, 0),
-						EnvOptions:        envOpts,
-						DeclTypes: []*apiservercel.DeclType{
-							namespaceType,
-							requestType,
-						},
-					},
-				)
+				decl := OptionalVariableDeclarations{HasParams: hasParams, HasAuthorizer: hasAuthorizer, StrictCost: strictCost}
+				envs[decl], err = createEnvForOpts(baseEnv, namespaceType, requestType, decl)
 				if err != nil {
-					panic(fmt.Sprintf("environment misconfigured: %v", err))
+					panic(err)
 				}
-				if strictCost {
-					extended, err = extended.Extend(environment.StrictCostOpt)
-					if err != nil {
-						panic(fmt.Sprintf("environment misconfigured: %v", err))
-					}
-				}
-				envs[OptionalVariableDeclarations{HasParams: hasParams, HasAuthorizer: hasAuthorizer, StrictCost: strictCost}] = extended
+			}
+			// We only need this ObjectTypes where strict cost is true
+			decl := OptionalVariableDeclarations{HasParams: hasParams, HasAuthorizer: hasAuthorizer, StrictCost: true, HasPatchTypes: true}
+			envs[decl], err = createEnvForOpts(baseEnv, namespaceType, requestType, decl)
+			if err != nil {
+				panic(err)
 			}
 		}
 	}
 	return envs
 }
+
+func createEnvForOpts(baseEnv *environment.EnvSet, namespaceType *apiservercel.DeclType, requestType *apiservercel.DeclType, opts OptionalVariableDeclarations) (*environment.EnvSet, error) {
+	var envOpts []cel.EnvOption
+	envOpts = append(envOpts,
+		cel.Variable(ObjectVarName, cel.DynType),
+		cel.Variable(OldObjectVarName, cel.DynType),
+		cel.Variable(NamespaceVarName, namespaceType.CelType()),
+		cel.Variable(RequestVarName, requestType.CelType()))
+	if opts.HasParams {
+		envOpts = append(envOpts, cel.Variable(ParamsVarName, cel.DynType))
+	}
+	if opts.HasAuthorizer {
+		envOpts = append(envOpts,
+			cel.Variable(AuthorizerVarName, library.AuthorizerType),
+			cel.Variable(RequestResourceAuthorizerVarName, library.ResourceCheckType))
+	}
+
+	extended, err := baseEnv.Extend(
+		environment.VersionedOptions{
+			// Feature epoch was actually 1.26, but we artificially set it to 1.0 because these
+			// options should always be present.
+			IntroducedVersion: version.MajorMinor(1, 0),
+			EnvOptions:        envOpts,
+			DeclTypes: []*apiservercel.DeclType{
+				namespaceType,
+				requestType,
+			},
+		},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("environment misconfigured: %w", err)
+	}
+	if opts.StrictCost {
+		extended, err = extended.Extend(environment.StrictCostOpt)
+		if err != nil {
+			return nil, fmt.Errorf("environment misconfigured: %w", err)
+		}
+	}
+
+	if opts.HasPatchTypes {
+		extended, err = extended.Extend(hasPatchTypes)
+		if err != nil {
+			return nil, fmt.Errorf("environment misconfigured: %w", err)
+		}
+	}
+	return extended, nil
+}
+
+var hasPatchTypes = environment.VersionedOptions{
+	// Feature epoch was actually 1.32, but we artificially set it to 1.0 because these
+	// options should always be present.
+	IntroducedVersion: version.MajorMinor(1, 0),
+	EnvOptions: []cel.EnvOption{
+		common.ResolverEnvOption(&mutation.DynamicTypeResolver{}),
+		environment.UnversionedLib(library.JSONPatch), // for jsonPatch.escape() function
+	},
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/composition.go

@@ -36,15 +36,27 @@ import (
 
 const VariablesTypeName = "kubernetes.variables"
 
+// CompositedCompiler compiles expressions with variable composition.
 type CompositedCompiler struct {
 	Compiler
-	FilterCompiler
+	ConditionCompiler
+	MutatingCompiler
 
 	CompositionEnv *CompositionEnv
 }
 
-type CompositedFilter struct {
-	Filter
+// CompositedConditionEvaluator provides evaluation of a condition expression with variable composition.
+// The expressions must return a boolean.
+type CompositedConditionEvaluator struct {
+	ConditionEvaluator
+
+	compositionEnv *CompositionEnv
+}
+
+// CompositedEvaluator provides evaluation of a single expression with variable composition.
+// The types that may returned by the expression is determined at compilation time.
+type CompositedEvaluator struct {
+	MutatingEvaluator
 
 	compositionEnv *CompositionEnv
 }
@@ -64,11 +76,13 @@ func NewCompositedCompilerFromTemplate(context *CompositionEnv) *CompositedCompi
 		CompiledVariables: map[string]CompilationResult{},
 	}
 	compiler := NewCompiler(context.EnvSet)
-	filterCompiler := NewFilterCompiler(context.EnvSet)
+	conditionCompiler := &conditionCompiler{compiler}
+	mutation := &mutatingCompiler{compiler}
 	return &CompositedCompiler{
-		Compiler:       compiler,
-		FilterCompiler: filterCompiler,
-		CompositionEnv: context,
+		Compiler:          compiler,
+		ConditionCompiler: conditionCompiler,
+		MutatingCompiler:  mutation,
+		CompositionEnv:    context,
 	}
 }
 
@@ -85,11 +99,20 @@ func (c *CompositedCompiler) CompileAndStoreVariable(variable NamedExpressionAcc
 	return result
 }
 
-func (c *CompositedCompiler) Compile(expressions []ExpressionAccessor, optionalDecls OptionalVariableDeclarations, envType environment.Type) Filter {
-	filter := c.FilterCompiler.Compile(expressions, optionalDecls, envType)
-	return &CompositedFilter{
-		Filter:         filter,
-		compositionEnv: c.CompositionEnv,
+func (c *CompositedCompiler) CompileCondition(expressions []ExpressionAccessor, optionalDecls OptionalVariableDeclarations, envType environment.Type) ConditionEvaluator {
+	condition := c.ConditionCompiler.CompileCondition(expressions, optionalDecls, envType)
+	return &CompositedConditionEvaluator{
+		ConditionEvaluator: condition,
+		compositionEnv:     c.CompositionEnv,
+	}
+}
+
+// CompileEvaluator compiles an mutatingEvaluator for the given expression, options and environment.
+func (c *CompositedCompiler) CompileMutatingEvaluator(expression ExpressionAccessor, optionalDecls OptionalVariableDeclarations, envType environment.Type) MutatingEvaluator {
+	mutation := c.MutatingCompiler.CompileMutatingEvaluator(expression, optionalDecls, envType)
+	return &CompositedEvaluator{
+		MutatingEvaluator: mutation,
+		compositionEnv:    c.CompositionEnv,
 	}
 }
 
@@ -160,9 +183,9 @@ func (c *compositionContext) Variables(activation any) ref.Val {
 	return lazyMap
 }
 
-func (f *CompositedFilter) ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *v1.AdmissionRequest, optionalVars OptionalVariableBindings, namespace *corev1.Namespace, runtimeCELCostBudget int64) ([]EvaluationResult, int64, error) {
+func (f *CompositedConditionEvaluator) ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *v1.AdmissionRequest, optionalVars OptionalVariableBindings, namespace *corev1.Namespace, runtimeCELCostBudget int64) ([]EvaluationResult, int64, error) {
 	ctx = f.compositionEnv.CreateContext(ctx)
-	return f.Filter.ForInput(ctx, versionedAttr, request, optionalVars, namespace, runtimeCELCostBudget)
+	return f.ConditionEvaluator.ForInput(ctx, versionedAttr, request, optionalVars, namespace, runtimeCELCostBudget)
 }
 
 func (c *compositionContext) reportCost(cost int64) {

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/condition.go

@@ -0,0 +1,216 @@
+/*
+Copyright 2022 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 cel
+
+import (
+	"context"
+	"reflect"
+
+	admissionv1 "k8s.io/api/admission/v1"
+	authenticationv1 "k8s.io/api/authentication/v1"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apiserver/pkg/admission"
+	"k8s.io/apiserver/pkg/cel/environment"
+)
+
+// conditionCompiler implement the interface ConditionCompiler.
+type conditionCompiler struct {
+	compiler Compiler
+}
+
+func NewConditionCompiler(env *environment.EnvSet) ConditionCompiler {
+	return &conditionCompiler{compiler: NewCompiler(env)}
+}
+
+// CompileCondition compiles the cel expressions defined in the ExpressionAccessors into a ConditionEvaluator
+func (c *conditionCompiler) CompileCondition(expressionAccessors []ExpressionAccessor, options OptionalVariableDeclarations, mode environment.Type) ConditionEvaluator {
+	compilationResults := make([]CompilationResult, len(expressionAccessors))
+	for i, expressionAccessor := range expressionAccessors {
+		if expressionAccessor == nil {
+			continue
+		}
+		compilationResults[i] = c.compiler.CompileCELExpression(expressionAccessor, options, mode)
+	}
+	return NewCondition(compilationResults)
+}
+
+// condition implements the ConditionEvaluator interface
+type condition struct {
+	compilationResults []CompilationResult
+}
+
+func NewCondition(compilationResults []CompilationResult) ConditionEvaluator {
+	return &condition{
+		compilationResults,
+	}
+}
+
+func convertObjectToUnstructured(obj interface{}) (*unstructured.Unstructured, error) {
+	if obj == nil || reflect.ValueOf(obj).IsNil() {
+		return &unstructured.Unstructured{Object: nil}, nil
+	}
+	ret, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)
+	if err != nil {
+		return nil, err
+	}
+	return &unstructured.Unstructured{Object: ret}, nil
+}
+
+func objectToResolveVal(r runtime.Object) (interface{}, error) {
+	if r == nil || reflect.ValueOf(r).IsNil() {
+		return nil, nil
+	}
+	v, err := convertObjectToUnstructured(r)
+	if err != nil {
+		return nil, err
+	}
+	return v.Object, nil
+}
+
+// ForInput evaluates the compiled CEL expressions converting them into CELEvaluations
+// errors per evaluation are returned on the Evaluation object
+// runtimeCELCostBudget was added for testing purpose only. Callers should always use const RuntimeCELCostBudget from k8s.io/apiserver/pkg/apis/cel/config.go as input.
+func (c *condition) ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *admissionv1.AdmissionRequest, inputs OptionalVariableBindings, namespace *v1.Namespace, runtimeCELCostBudget int64) ([]EvaluationResult, int64, error) {
+	// TODO: replace unstructured with ref.Val for CEL variables when native type support is available
+	evaluations := make([]EvaluationResult, len(c.compilationResults))
+	var err error
+
+	// if this activation supports composition, we will need the compositionCtx. It may be nil.
+	compositionCtx, _ := ctx.(CompositionContext)
+
+	activation, err := newActivation(compositionCtx, versionedAttr, request, inputs, namespace)
+	if err != nil {
+		return nil, -1, err
+	}
+
+	remainingBudget := runtimeCELCostBudget
+	for i, compilationResult := range c.compilationResults {
+		evaluations[i], remainingBudget, err = activation.Evaluate(ctx, compositionCtx, compilationResult, remainingBudget)
+		if err != nil {
+			return nil, -1, err
+		}
+	}
+
+	return evaluations, remainingBudget, nil
+}
+
+// TODO: to reuse https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/request/admissionreview.go#L154
+func CreateAdmissionRequest(attr admission.Attributes, equivalentGVR metav1.GroupVersionResource, equivalentKind metav1.GroupVersionKind) *admissionv1.AdmissionRequest {
+	// Attempting to use same logic as webhook for constructing resource
+	// GVK, GVR, subresource
+	// Use the GVK, GVR that the matcher decided was equivalent to that of the request
+	// https://github.com/kubernetes/kubernetes/blob/90c362b3430bcbbf8f245fadbcd521dab39f1d7c/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/generic/webhook.go#L182-L210
+	gvk := equivalentKind
+	gvr := equivalentGVR
+	subresource := attr.GetSubresource()
+
+	requestGVK := attr.GetKind()
+	requestGVR := attr.GetResource()
+	requestSubResource := attr.GetSubresource()
+
+	aUserInfo := attr.GetUserInfo()
+	var userInfo authenticationv1.UserInfo
+	if aUserInfo != nil {
+		userInfo = authenticationv1.UserInfo{
+			Extra:    make(map[string]authenticationv1.ExtraValue),
+			Groups:   aUserInfo.GetGroups(),
+			UID:      aUserInfo.GetUID(),
+			Username: aUserInfo.GetName(),
+		}
+		// Convert the extra information in the user object
+		for key, val := range aUserInfo.GetExtra() {
+			userInfo.Extra[key] = authenticationv1.ExtraValue(val)
+		}
+	}
+
+	dryRun := attr.IsDryRun()
+
+	return &admissionv1.AdmissionRequest{
+		Kind: metav1.GroupVersionKind{
+			Group:   gvk.Group,
+			Kind:    gvk.Kind,
+			Version: gvk.Version,
+		},
+		Resource: metav1.GroupVersionResource{
+			Group:    gvr.Group,
+			Resource: gvr.Resource,
+			Version:  gvr.Version,
+		},
+		SubResource: subresource,
+		RequestKind: &metav1.GroupVersionKind{
+			Group:   requestGVK.Group,
+			Kind:    requestGVK.Kind,
+			Version: requestGVK.Version,
+		},
+		RequestResource: &metav1.GroupVersionResource{
+			Group:    requestGVR.Group,
+			Resource: requestGVR.Resource,
+			Version:  requestGVR.Version,
+		},
+		RequestSubResource: requestSubResource,
+		Name:               attr.GetName(),
+		Namespace:          attr.GetNamespace(),
+		Operation:          admissionv1.Operation(attr.GetOperation()),
+		UserInfo:           userInfo,
+		// Leave Object and OldObject unset since we don't provide access to them via request
+		DryRun: &dryRun,
+		Options: runtime.RawExtension{
+			Object: attr.GetOperationOptions(),
+		},
+	}
+}
+
+// CreateNamespaceObject creates a Namespace object that is suitable for the CEL evaluation.
+// If the namespace is nil, CreateNamespaceObject returns nil
+func CreateNamespaceObject(namespace *v1.Namespace) *v1.Namespace {
+	if namespace == nil {
+		return nil
+	}
+
+	return &v1.Namespace{
+		Status: namespace.Status,
+		Spec:   namespace.Spec,
+		ObjectMeta: metav1.ObjectMeta{
+			Name:                       namespace.Name,
+			GenerateName:               namespace.GenerateName,
+			Namespace:                  namespace.Namespace,
+			UID:                        namespace.UID,
+			ResourceVersion:            namespace.ResourceVersion,
+			Generation:                 namespace.Generation,
+			CreationTimestamp:          namespace.CreationTimestamp,
+			DeletionTimestamp:          namespace.DeletionTimestamp,
+			DeletionGracePeriodSeconds: namespace.DeletionGracePeriodSeconds,
+			Labels:                     namespace.Labels,
+			Annotations:                namespace.Annotations,
+			Finalizers:                 namespace.Finalizers,
+		},
+	}
+}
+
+// CompilationErrors returns a list of all the errors from the compilation of the mutatingEvaluator
+func (c *condition) CompilationErrors() []error {
+	compilationErrors := []error{}
+	for _, result := range c.compilationResults {
+		if result.Error != nil {
+			compilationErrors = append(compilationErrors, result.Error)
+		}
+	}
+	return compilationErrors
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/filter.go

@@ -1,361 +0,0 @@
-/*
-Copyright 2022 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 cel
-
-import (
-	"context"
-	"fmt"
-	"math"
-	"reflect"
-	"time"
-
-	"github.com/google/cel-go/interpreter"
-
-	admissionv1 "k8s.io/api/admission/v1"
-	authenticationv1 "k8s.io/api/authentication/v1"
-	v1 "k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
-	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apiserver/pkg/admission"
-	"k8s.io/apiserver/pkg/cel"
-	"k8s.io/apiserver/pkg/cel/environment"
-	"k8s.io/apiserver/pkg/cel/library"
-)
-
-// filterCompiler implement the interface FilterCompiler.
-type filterCompiler struct {
-	compiler Compiler
-}
-
-func NewFilterCompiler(env *environment.EnvSet) FilterCompiler {
-	return &filterCompiler{compiler: NewCompiler(env)}
-}
-
-type evaluationActivation struct {
-	object, oldObject, params, request, namespace, authorizer, requestResourceAuthorizer, variables interface{}
-}
-
-// ResolveName returns a value from the activation by qualified name, or false if the name
-// could not be found.
-func (a *evaluationActivation) ResolveName(name string) (interface{}, bool) {
-	switch name {
-	case ObjectVarName:
-		return a.object, true
-	case OldObjectVarName:
-		return a.oldObject, true
-	case ParamsVarName:
-		return a.params, true // params may be null
-	case RequestVarName:
-		return a.request, true
-	case NamespaceVarName:
-		return a.namespace, true
-	case AuthorizerVarName:
-		return a.authorizer, a.authorizer != nil
-	case RequestResourceAuthorizerVarName:
-		return a.requestResourceAuthorizer, a.requestResourceAuthorizer != nil
-	case VariableVarName: // variables always present
-		return a.variables, true
-	default:
-		return nil, false
-	}
-}
-
-// Parent returns the parent of the current activation, may be nil.
-// If non-nil, the parent will be searched during resolve calls.
-func (a *evaluationActivation) Parent() interpreter.Activation {
-	return nil
-}
-
-// Compile compiles the cel expressions defined in the ExpressionAccessors into a Filter
-func (c *filterCompiler) Compile(expressionAccessors []ExpressionAccessor, options OptionalVariableDeclarations, mode environment.Type) Filter {
-	compilationResults := make([]CompilationResult, len(expressionAccessors))
-	for i, expressionAccessor := range expressionAccessors {
-		if expressionAccessor == nil {
-			continue
-		}
-		compilationResults[i] = c.compiler.CompileCELExpression(expressionAccessor, options, mode)
-	}
-	return NewFilter(compilationResults)
-}
-
-// filter implements the Filter interface
-type filter struct {
-	compilationResults []CompilationResult
-}
-
-func NewFilter(compilationResults []CompilationResult) Filter {
-	return &filter{
-		compilationResults,
-	}
-}
-
-func convertObjectToUnstructured(obj interface{}) (*unstructured.Unstructured, error) {
-	if obj == nil || reflect.ValueOf(obj).IsNil() {
-		return &unstructured.Unstructured{Object: nil}, nil
-	}
-	ret, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)
-	if err != nil {
-		return nil, err
-	}
-	return &unstructured.Unstructured{Object: ret}, nil
-}
-
-func objectToResolveVal(r runtime.Object) (interface{}, error) {
-	if r == nil || reflect.ValueOf(r).IsNil() {
-		return nil, nil
-	}
-	v, err := convertObjectToUnstructured(r)
-	if err != nil {
-		return nil, err
-	}
-	return v.Object, nil
-}
-
-// ForInput evaluates the compiled CEL expressions converting them into CELEvaluations
-// errors per evaluation are returned on the Evaluation object
-// runtimeCELCostBudget was added for testing purpose only. Callers should always use const RuntimeCELCostBudget from k8s.io/apiserver/pkg/apis/cel/config.go as input.
-func (f *filter) ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *admissionv1.AdmissionRequest, inputs OptionalVariableBindings, namespace *v1.Namespace, runtimeCELCostBudget int64) ([]EvaluationResult, int64, error) {
-	// TODO: replace unstructured with ref.Val for CEL variables when native type support is available
-	evaluations := make([]EvaluationResult, len(f.compilationResults))
-	var err error
-
-	oldObjectVal, err := objectToResolveVal(versionedAttr.VersionedOldObject)
-	if err != nil {
-		return nil, -1, err
-	}
-	objectVal, err := objectToResolveVal(versionedAttr.VersionedObject)
-	if err != nil {
-		return nil, -1, err
-	}
-	var paramsVal, authorizerVal, requestResourceAuthorizerVal any
-	if inputs.VersionedParams != nil {
-		paramsVal, err = objectToResolveVal(inputs.VersionedParams)
-		if err != nil {
-			return nil, -1, err
-		}
-	}
-
-	if inputs.Authorizer != nil {
-		authorizerVal = library.NewAuthorizerVal(versionedAttr.GetUserInfo(), inputs.Authorizer)
-		requestResourceAuthorizerVal = library.NewResourceAuthorizerVal(versionedAttr.GetUserInfo(), inputs.Authorizer, versionedAttr)
-	}
-
-	requestVal, err := convertObjectToUnstructured(request)
-	if err != nil {
-		return nil, -1, err
-	}
-	namespaceVal, err := objectToResolveVal(namespace)
-	if err != nil {
-		return nil, -1, err
-	}
-	va := &evaluationActivation{
-		object:                    objectVal,
-		oldObject:                 oldObjectVal,
-		params:                    paramsVal,
-		request:                   requestVal.Object,
-		namespace:                 namespaceVal,
-		authorizer:                authorizerVal,
-		requestResourceAuthorizer: requestResourceAuthorizerVal,
-	}
-
-	// composition is an optional feature that only applies for ValidatingAdmissionPolicy.
-	// check if the context allows composition
-	var compositionCtx CompositionContext
-	var ok bool
-	if compositionCtx, ok = ctx.(CompositionContext); ok {
-		va.variables = compositionCtx.Variables(va)
-	}
-
-	remainingBudget := runtimeCELCostBudget
-	for i, compilationResult := range f.compilationResults {
-		var evaluation = &evaluations[i]
-		if compilationResult.ExpressionAccessor == nil { // in case of placeholder
-			continue
-		}
-		evaluation.ExpressionAccessor = compilationResult.ExpressionAccessor
-		if compilationResult.Error != nil {
-			evaluation.Error = &cel.Error{
-				Type:   cel.ErrorTypeInvalid,
-				Detail: fmt.Sprintf("compilation error: %v", compilationResult.Error),
-				Cause:  compilationResult.Error,
-			}
-			continue
-		}
-		if compilationResult.Program == nil {
-			evaluation.Error = &cel.Error{
-				Type:   cel.ErrorTypeInternal,
-				Detail: fmt.Sprintf("unexpected internal error compiling expression"),
-			}
-			continue
-		}
-		t1 := time.Now()
-		evalResult, evalDetails, err := compilationResult.Program.ContextEval(ctx, va)
-		// budget may be spent due to lazy evaluation of composited variables
-		if compositionCtx != nil {
-			compositionCost := compositionCtx.GetAndResetCost()
-			if compositionCost > remainingBudget {
-				return nil, -1, &cel.Error{
-					Type:   cel.ErrorTypeInvalid,
-					Detail: fmt.Sprintf("validation failed due to running out of cost budget, no further validation rules will be run"),
-					Cause:  cel.ErrOutOfBudget,
-				}
-			}
-			remainingBudget -= compositionCost
-		}
-		elapsed := time.Since(t1)
-		evaluation.Elapsed = elapsed
-		if evalDetails == nil {
-			return nil, -1, &cel.Error{
-				Type:   cel.ErrorTypeInternal,
-				Detail: fmt.Sprintf("runtime cost could not be calculated for expression: %v, no further expression will be run", compilationResult.ExpressionAccessor.GetExpression()),
-			}
-		} else {
-			rtCost := evalDetails.ActualCost()
-			if rtCost == nil {
-				return nil, -1, &cel.Error{
-					Type:   cel.ErrorTypeInvalid,
-					Detail: fmt.Sprintf("runtime cost could not be calculated for expression: %v, no further expression will be run", compilationResult.ExpressionAccessor.GetExpression()),
-					Cause:  cel.ErrOutOfBudget,
-				}
-			} else {
-				if *rtCost > math.MaxInt64 || int64(*rtCost) > remainingBudget {
-					return nil, -1, &cel.Error{
-						Type:   cel.ErrorTypeInvalid,
-						Detail: fmt.Sprintf("validation failed due to running out of cost budget, no further validation rules will be run"),
-						Cause:  cel.ErrOutOfBudget,
-					}
-				}
-				remainingBudget -= int64(*rtCost)
-			}
-		}
-		if err != nil {
-			evaluation.Error = &cel.Error{
-				Type:   cel.ErrorTypeInvalid,
-				Detail: fmt.Sprintf("expression '%v' resulted in error: %v", compilationResult.ExpressionAccessor.GetExpression(), err),
-			}
-		} else {
-			evaluation.EvalResult = evalResult
-		}
-	}
-
-	return evaluations, remainingBudget, nil
-}
-
-// TODO: to reuse https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/request/admissionreview.go#L154
-func CreateAdmissionRequest(attr admission.Attributes, equivalentGVR metav1.GroupVersionResource, equivalentKind metav1.GroupVersionKind) *admissionv1.AdmissionRequest {
-	// Attempting to use same logic as webhook for constructing resource
-	// GVK, GVR, subresource
-	// Use the GVK, GVR that the matcher decided was equivalent to that of the request
-	// https://github.com/kubernetes/kubernetes/blob/90c362b3430bcbbf8f245fadbcd521dab39f1d7c/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/generic/webhook.go#L182-L210
-	gvk := equivalentKind
-	gvr := equivalentGVR
-	subresource := attr.GetSubresource()
-
-	requestGVK := attr.GetKind()
-	requestGVR := attr.GetResource()
-	requestSubResource := attr.GetSubresource()
-
-	aUserInfo := attr.GetUserInfo()
-	var userInfo authenticationv1.UserInfo
-	if aUserInfo != nil {
-		userInfo = authenticationv1.UserInfo{
-			Extra:    make(map[string]authenticationv1.ExtraValue),
-			Groups:   aUserInfo.GetGroups(),
-			UID:      aUserInfo.GetUID(),
-			Username: aUserInfo.GetName(),
-		}
-		// Convert the extra information in the user object
-		for key, val := range aUserInfo.GetExtra() {
-			userInfo.Extra[key] = authenticationv1.ExtraValue(val)
-		}
-	}
-
-	dryRun := attr.IsDryRun()
-
-	return &admissionv1.AdmissionRequest{
-		Kind: metav1.GroupVersionKind{
-			Group:   gvk.Group,
-			Kind:    gvk.Kind,
-			Version: gvk.Version,
-		},
-		Resource: metav1.GroupVersionResource{
-			Group:    gvr.Group,
-			Resource: gvr.Resource,
-			Version:  gvr.Version,
-		},
-		SubResource: subresource,
-		RequestKind: &metav1.GroupVersionKind{
-			Group:   requestGVK.Group,
-			Kind:    requestGVK.Kind,
-			Version: requestGVK.Version,
-		},
-		RequestResource: &metav1.GroupVersionResource{
-			Group:    requestGVR.Group,
-			Resource: requestGVR.Resource,
-			Version:  requestGVR.Version,
-		},
-		RequestSubResource: requestSubResource,
-		Name:               attr.GetName(),
-		Namespace:          attr.GetNamespace(),
-		Operation:          admissionv1.Operation(attr.GetOperation()),
-		UserInfo:           userInfo,
-		// Leave Object and OldObject unset since we don't provide access to them via request
-		DryRun: &dryRun,
-		Options: runtime.RawExtension{
-			Object: attr.GetOperationOptions(),
-		},
-	}
-}
-
-// CreateNamespaceObject creates a Namespace object that is suitable for the CEL evaluation.
-// If the namespace is nil, CreateNamespaceObject returns nil
-func CreateNamespaceObject(namespace *v1.Namespace) *v1.Namespace {
-	if namespace == nil {
-		return nil
-	}
-
-	return &v1.Namespace{
-		Status: namespace.Status,
-		Spec:   namespace.Spec,
-		ObjectMeta: metav1.ObjectMeta{
-			Name:                       namespace.Name,
-			GenerateName:               namespace.GenerateName,
-			Namespace:                  namespace.Namespace,
-			UID:                        namespace.UID,
-			ResourceVersion:            namespace.ResourceVersion,
-			Generation:                 namespace.Generation,
-			CreationTimestamp:          namespace.CreationTimestamp,
-			DeletionTimestamp:          namespace.DeletionTimestamp,
-			DeletionGracePeriodSeconds: namespace.DeletionGracePeriodSeconds,
-			Labels:                     namespace.Labels,
-			Annotations:                namespace.Annotations,
-			Finalizers:                 namespace.Finalizers,
-		},
-	}
-}
-
-// CompilationErrors returns a list of all the errors from the compilation of the evaluator
-func (e *filter) CompilationErrors() []error {
-	compilationErrors := []error{}
-	for _, result := range e.compilationResults {
-		if result.Error != nil {
-			compilationErrors = append(compilationErrors, result.Error)
-		}
-	}
-	return compilationErrors
-}

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/interface.go

@@ -63,12 +63,15 @@ type OptionalVariableDeclarations struct {
 	HasAuthorizer bool
 	// StrictCost specifies if the CEL cost limitation is strict for extended libraries as well as native libraries.
 	StrictCost bool
+	// HasPatchTypes specifies if JSONPatch, Object, Object.metadata and similar types are available in CEL. These can be used
+	// to initialize the typed objects in CEL required to create patches.
+	HasPatchTypes bool
 }
 
-// FilterCompiler contains a function to assist with converting types and values to/from CEL-typed values.
-type FilterCompiler interface {
-	// Compile is used for the cel expression compilation
-	Compile(expressions []ExpressionAccessor, optionalDecls OptionalVariableDeclarations, envType environment.Type) Filter
+// ConditionCompiler contains a function to assist with converting types and values to/from CEL-typed values.
+type ConditionCompiler interface {
+	// CompileCondition is used for the cel expression compilation
+	CompileCondition(expressions []ExpressionAccessor, optionalDecls OptionalVariableDeclarations, envType environment.Type) ConditionEvaluator
 }
 
 // OptionalVariableBindings provides expression bindings for optional CEL variables.
@@ -82,16 +85,38 @@ type OptionalVariableBindings struct {
 	Authorizer authorizer.Authorizer
 }
 
-// Filter contains a function to evaluate compiled CEL-typed values
+// ConditionEvaluator contains the result of compiling a CEL expression
+// that evaluates to a condition. This is used both for validation and pre-conditions.
 // It expects the inbound object to already have been converted to the version expected
 // by the underlying CEL code (which is indicated by the match criteria of a policy definition).
 // versionedParams may be nil.
-type Filter interface {
+type ConditionEvaluator interface {
 	// ForInput converts compiled CEL-typed values into evaluated CEL-typed value.
 	// runtimeCELCostBudget was added for testing purpose only. Callers should always use const RuntimeCELCostBudget from k8s.io/apiserver/pkg/apis/cel/config.go as input.
-	// If cost budget is calculated, the filter should return the remaining budget.
+	// If cost budget is calculated, the condition should return the remaining budget.
 	ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *v1.AdmissionRequest, optionalVars OptionalVariableBindings, namespace *corev1.Namespace, runtimeCELCostBudget int64) ([]EvaluationResult, int64, error)
 
-	// CompilationErrors returns a list of errors from the compilation of the evaluator
+	// CompilationErrors returns a list of errors from the compilation of the mutatingEvaluator
+	CompilationErrors() []error
+}
+
+// MutatingCompiler contains a function to assist with converting types and values to/from CEL-typed values.
+type MutatingCompiler interface {
+	// CompileMutatingEvaluator is used for the cel expression compilation
+	CompileMutatingEvaluator(expression ExpressionAccessor, optionalDecls OptionalVariableDeclarations, envType environment.Type) MutatingEvaluator
+}
+
+// MutatingEvaluator contains the result of compiling a CEL expression
+// that evaluates to a mutation.
+// It expects the inbound object to already have been converted to the version expected
+// by the underlying CEL code (which is indicated by the match criteria of a policy definition).
+// versionedParams may be nil.
+type MutatingEvaluator interface {
+	// ForInput converts compiled CEL-typed values into a CEL-typed value representing a mutation.
+	// runtimeCELCostBudget was added for testing purpose only. Callers should always use const RuntimeCELCostBudget from k8s.io/apiserver/pkg/apis/cel/config.go as input.
+	// If cost budget is calculated, the condition should return the remaining budget.
+	ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *v1.AdmissionRequest, optionalVars OptionalVariableBindings, namespace *corev1.Namespace, runtimeCELCostBudget int64) (EvaluationResult, int64, error)
+
+	// CompilationErrors returns a list of errors from the compilation of the mutatingEvaluator
 	CompilationErrors() []error
 }

vendor/k8s.io/apiserver/pkg/admission/plugin/cel/mutation.go

@@ -0,0 +1,73 @@
+/*
+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 cel
+
+import (
+	"context"
+
+	admissionv1 "k8s.io/api/admission/v1"
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apiserver/pkg/admission"
+	"k8s.io/apiserver/pkg/cel/environment"
+)
+
+// mutatingCompiler provides a MutatingCompiler implementation.
+type mutatingCompiler struct {
+	compiler Compiler
+}
+
+// CompileMutatingEvaluator compiles a CEL expression for admission plugins and returns an MutatingEvaluator for executing the
+// compiled CEL expression.
+func (p *mutatingCompiler) CompileMutatingEvaluator(expressionAccessor ExpressionAccessor, options OptionalVariableDeclarations, mode environment.Type) MutatingEvaluator {
+	compilationResult := p.compiler.CompileCELExpression(expressionAccessor, options, mode)
+	return NewMutatingEvaluator(compilationResult)
+}
+
+type mutatingEvaluator struct {
+	compilationResult CompilationResult
+}
+
+func NewMutatingEvaluator(compilationResult CompilationResult) MutatingEvaluator {
+	return &mutatingEvaluator{compilationResult}
+}
+
+// ForInput evaluates the compiled CEL expression and returns an evaluation result
+// errors per evaluation are returned in the evaluation result
+// runtimeCELCostBudget was added for testing purpose only. Callers should always use const RuntimeCELCostBudget from k8s.io/apiserver/pkg/apis/cel/config.go as input.
+func (p *mutatingEvaluator) ForInput(ctx context.Context, versionedAttr *admission.VersionedAttributes, request *admissionv1.AdmissionRequest, inputs OptionalVariableBindings, namespace *v1.Namespace, runtimeCELCostBudget int64) (EvaluationResult, int64, error) {
+	// if this activation supports composition, we will need the compositionCtx. It may be nil.
+	compositionCtx, _ := ctx.(CompositionContext)
+
+	activation, err := newActivation(compositionCtx, versionedAttr, request, inputs, namespace)
+	if err != nil {
+		return EvaluationResult{}, -1, err
+	}
+	evaluation, remainingBudget, err := activation.Evaluate(ctx, compositionCtx, p.compilationResult, runtimeCELCostBudget)
+	if err != nil {
+		return evaluation, -1, err
+	}
+	return evaluation, remainingBudget, nil
+
+}
+
+// CompilationErrors returns a list of all the errors from the compilation of the mutatingEvaluator
+func (p *mutatingEvaluator) CompilationErrors() (compilationErrors []error) {
+	if p.compilationResult.Error != nil {
+		return []error{p.compilationResult.Error}
+	}
+	return nil
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/generic/accessor.go

@@ -26,6 +26,7 @@ type PolicyAccessor interface {
 	GetNamespace() string
 	GetParamKind() *v1.ParamKind
 	GetMatchConstraints() *v1.MatchResources
+	GetFailurePolicy() *v1.FailurePolicyType
 }
 
 type BindingAccessor interface {

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/generic/interfaces.go

@@ -49,6 +49,9 @@ type Source[H Hook] interface {
 // Dispatcher dispatches evaluates an admission request against the currently
 // active hooks returned by the source.
 type Dispatcher[H Hook] interface {
+	// Start the dispatcher. This method should be called only once at startup.
+	Start(ctx context.Context) error
+
 	// Dispatch a request to the policies. Dispatcher may choose not to
 	// call a hook, either because the rules of the hook does not match, or
 	// the namespaceSelector or the objectSelector of the hook does not

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/generic/plugin.go

@@ -36,8 +36,9 @@ import (
 )
 
 // H is the Hook type generated by the source and consumed by the dispatcher.
+// !TODO: Just pass in a Plugin[H] with accessors to all this information
 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]
+type dispatcherFactory[H any] func(authorizer.Authorizer, *matching.Matcher, kubernetes.Interface) Dispatcher[H]
 
 // admissionResources is the list of resources related to CEL-based admission
 // features.
@@ -170,7 +171,7 @@ func (c *Plugin[H]) ValidateInitialization() error {
 	}
 
 	c.source = c.sourceFactory(c.informerFactory, c.client, c.dynamicClient, c.restMapper)
-	c.dispatcher = c.dispatcherFactory(c.authorizer, c.matcher)
+	c.dispatcher = c.dispatcherFactory(c.authorizer, c.matcher, c.client)
 
 	pluginContext, pluginContextCancel := context.WithCancel(context.Background())
 	go func() {
@@ -181,10 +182,15 @@ func (c *Plugin[H]) ValidateInitialization() error {
 	go func() {
 		err := c.source.Run(pluginContext)
 		if err != nil && !errors.Is(err, context.Canceled) {
-			utilruntime.HandleError(fmt.Errorf("policy source context unexpectedly closed: %v", err))
+			utilruntime.HandleError(fmt.Errorf("policy source context unexpectedly closed: %w", err))
 		}
 	}()
 
+	err := c.dispatcher.Start(pluginContext)
+	if err != nil && !errors.Is(err, context.Canceled) {
+		utilruntime.HandleError(fmt.Errorf("policy dispatcher context unexpectedly closed: %w", err))
+	}
+
 	c.SetReadyFunc(func() bool {
 		return namespaceInformer.Informer().HasSynced() && c.source.HasSynced()
 	})

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/generic/policy_dispatcher.go

@@ -36,7 +36,7 @@ import (
 	"k8s.io/client-go/tools/cache"
 )
 
-// A policy invocation is a single policy-binding-param tuple from a Policy Hook
+// PolicyInvocation is a single policy-binding-param tuple from a Policy Hook
 // in the context of a specific request. The params have already been resolved
 // and any error in configuration or setting up the invocation is stored in
 // the Error field.
@@ -62,10 +62,6 @@ type PolicyInvocation[P runtime.Object, B runtime.Object, E Evaluator] struct {
 
 	// Params fetched by the binding to use to evaluate the policy
 	Param runtime.Object
-
-	// Error is set if there was an error with the policy or binding or its
-	// params, etc
-	Error error
 }
 
 // dispatcherDelegate is called during a request with a pre-filtered list
@@ -76,7 +72,7 @@ type PolicyInvocation[P runtime.Object, B runtime.Object, E Evaluator] struct {
 //
 // The delegate provides the "validation" or "mutation" aspect of dispatcher functionality
 // (in contrast to generic.PolicyDispatcher which only selects active policies and params)
-type dispatcherDelegate[P, B runtime.Object, E Evaluator] func(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces, versionedAttributes webhookgeneric.VersionedAttributeAccessor, invocations []PolicyInvocation[P, B, E]) error
+type dispatcherDelegate[P, B runtime.Object, E Evaluator] func(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces, versionedAttributes webhookgeneric.VersionedAttributeAccessor, invocations []PolicyInvocation[P, B, E]) ([]PolicyError, *apierrors.StatusError)
 
 type policyDispatcher[P runtime.Object, B runtime.Object, E Evaluator] struct {
 	newPolicyAccessor  func(P) PolicyAccessor
@@ -104,7 +100,10 @@ func NewPolicyDispatcher[P runtime.Object, B runtime.Object, E Evaluator](
 // request. It then resolves all params and creates an Invocation for each
 // matching policy-binding-param tuple. The delegate is then called with the
 // list of tuples.
-//
+func (d *policyDispatcher[P, B, E]) Start(ctx context.Context) error {
+	return nil
+}
+
 // Note: MatchConditions expressions are not evaluated here. The dispatcher delegate
 // is expected to ignore the result of any policies whose match conditions dont pass.
 // This may be possible to refactor so matchconditions are checked here instead.
@@ -117,29 +116,33 @@ func (d *policyDispatcher[P, B, E]) Dispatch(ctx context.Context, a admission.At
 		objectInterfaces: o,
 	}
 
+	var policyErrors []PolicyError
+	addConfigError := func(err error, definition PolicyAccessor, binding BindingAccessor) {
+		var message error
+		if binding == nil {
+			message = fmt.Errorf("failed to configure policy: %w", err)
+		} else {
+			message = fmt.Errorf("failed to configure binding: %w", err)
+		}
+
+		policyErrors = append(policyErrors, PolicyError{
+			Policy:  definition,
+			Binding: binding,
+			Message: message,
+		})
+	}
+
 	for _, hook := range hooks {
 		policyAccessor := d.newPolicyAccessor(hook.Policy)
 		matches, matchGVR, matchGVK, err := d.matcher.DefinitionMatches(a, o, policyAccessor)
 		if err != nil {
 			// There was an error evaluating if this policy matches anything.
-			utilruntime.HandleError(err)
-			relevantHooks = append(relevantHooks, PolicyInvocation[P, B, E]{
-				Policy: hook.Policy,
-				Error:  err,
-			})
+			addConfigError(err, policyAccessor, nil)
 			continue
 		} else if !matches {
 			continue
 		} else if hook.ConfigurationError != nil {
-			// The policy matches but there is a configuration error with the
-			// policy itself
-			relevantHooks = append(relevantHooks, PolicyInvocation[P, B, E]{
-				Policy:   hook.Policy,
-				Error:    hook.ConfigurationError,
-				Resource: matchGVR,
-				Kind:     matchGVK,
-			})
-			utilruntime.HandleError(hook.ConfigurationError)
+			addConfigError(hook.ConfigurationError, policyAccessor, nil)
 			continue
 		}
 
@@ -148,19 +151,22 @@ func (d *policyDispatcher[P, B, E]) Dispatch(ctx context.Context, a admission.At
 			matches, err = d.matcher.BindingMatches(a, o, bindingAccessor)
 			if err != nil {
 				// There was an error evaluating if this binding matches anything.
-				utilruntime.HandleError(err)
-				relevantHooks = append(relevantHooks, PolicyInvocation[P, B, E]{
-					Policy:   hook.Policy,
-					Binding:  binding,
-					Error:    err,
-					Resource: matchGVR,
-					Kind:     matchGVK,
-				})
+				addConfigError(err, policyAccessor, bindingAccessor)
 				continue
 			} else if !matches {
 				continue
 			}
 
+			// here the binding matches.
+			// VersionedAttr result will be cached and reused later during parallel
+			// hook calls.
+			if _, err = versionedAttrAccessor.VersionedAttribute(matchGVK); err != nil {
+				// VersionedAttr result will be cached and reused later during parallel
+				// hook calls.
+				addConfigError(err, policyAccessor, nil)
+				continue
+			}
+
 			// Collect params for this binding
 			params, err := CollectParams(
 				policyAccessor.GetParamKind(),
@@ -171,14 +177,7 @@ func (d *policyDispatcher[P, B, E]) Dispatch(ctx context.Context, a admission.At
 			)
 			if err != nil {
 				// There was an error collecting params for this binding.
-				utilruntime.HandleError(err)
-				relevantHooks = append(relevantHooks, PolicyInvocation[P, B, E]{
-					Policy:   hook.Policy,
-					Binding:  binding,
-					Error:    err,
-					Resource: matchGVR,
-					Kind:     matchGVK,
-				})
+				addConfigError(err, policyAccessor, bindingAccessor)
 				continue
 			}
 
@@ -194,23 +193,72 @@ func (d *policyDispatcher[P, B, E]) Dispatch(ctx context.Context, a admission.At
 					Evaluator: hook.Evaluator,
 				})
 			}
+		}
+	}
 
-			// VersionedAttr result will be cached and reused later during parallel
-			// hook calls
-			_, err = versionedAttrAccessor.VersionedAttribute(matchGVK)
-			if err != nil {
-				return apierrors.NewInternalError(err)
-			}
+	if len(relevantHooks) > 0 {
+		extraPolicyErrors, statusError := d.delegate(ctx, a, o, versionedAttrAccessor, relevantHooks)
+		if statusError != nil {
+			return statusError
+		}
+		policyErrors = append(policyErrors, extraPolicyErrors...)
+	}
+
+	var filteredErrors []PolicyError
+	for _, e := range policyErrors {
+		// we always default the FailurePolicy if it is unset and validate it in API level
+		var policy v1.FailurePolicyType
+		if fp := e.Policy.GetFailurePolicy(); fp == nil {
+			policy = v1.Fail
+		} else {
+			policy = *fp
 		}
 
+		switch policy {
+		case v1.Ignore:
+			// TODO: add metrics for ignored error here
+			continue
+		case v1.Fail:
+			filteredErrors = append(filteredErrors, e)
+		default:
+			filteredErrors = append(filteredErrors, e)
+		}
 	}
 
-	if len(relevantHooks) == 0 {
-		// no matching hooks
-		return nil
+	if len(filteredErrors) > 0 {
+
+		forbiddenErr := admission.NewForbidden(a, fmt.Errorf("admission request denied by policy"))
+
+		// The forbiddenErr is always a StatusError.
+		var err *apierrors.StatusError
+		if !errors.As(forbiddenErr, &err) {
+			// Should never happen.
+			return apierrors.NewInternalError(fmt.Errorf("failed to create status error"))
+		}
+		err.ErrStatus.Message = ""
+
+		for _, policyError := range filteredErrors {
+			message := policyError.Error()
+
+			// If this is the first denied decision, use its message and reason
+			// for the status error message.
+			if err.ErrStatus.Message == "" {
+				err.ErrStatus.Message = message
+				if policyError.Reason != "" {
+					err.ErrStatus.Reason = policyError.Reason
+				}
+			}
+
+			// Add the denied decision's message to the status error's details
+			err.ErrStatus.Details.Causes = append(
+				err.ErrStatus.Details.Causes,
+				metav1.StatusCause{Message: message})
+		}
+
+		return err
 	}
 
-	return d.delegate(ctx, a, o, versionedAttrAccessor, relevantHooks)
+	return nil
 }
 
 // Returns params to use to evaluate a policy-binding with given param
@@ -352,3 +400,18 @@ func (v *versionedAttributeAccessor) VersionedAttribute(gvk schema.GroupVersionK
 	v.versionedAttrs[gvk] = versionedAttr
 	return versionedAttr, nil
 }
+
+type PolicyError struct {
+	Policy  PolicyAccessor
+	Binding BindingAccessor
+	Message error
+	Reason  metav1.StatusReason
+}
+
+func (c PolicyError) Error() string {
+	if c.Binding != nil {
+		return fmt.Sprintf("policy '%s' with binding '%s' denied request: %s", c.Policy.GetName(), c.Binding.GetName(), c.Message.Error())
+	}
+
+	return fmt.Sprintf("policy %q denied request: %s", c.Policy.GetName(), c.Message.Error())
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/generic/policy_source.go

@@ -41,6 +41,13 @@ import (
 	"k8s.io/klog/v2"
 )
 
+// Interval for refreshing policies.
+// TODO: Consider reducing this to a shorter duration or replacing this entirely
+// with checks that detect when a policy change took effect.
+const policyRefreshIntervalDefault = 1 * time.Second
+
+var policyRefreshInterval = policyRefreshIntervalDefault
+
 type policySource[P runtime.Object, B runtime.Object, E Evaluator] struct {
 	ctx                context.Context
 	policyInformer     generic.Informer[P]
@@ -122,6 +129,15 @@ func NewPolicySource[P runtime.Object, B runtime.Object, E Evaluator](
 	return res
 }
 
+// SetPolicyRefreshIntervalForTests allows the refresh interval to be overridden during tests.
+// This should only be called from tests.
+func SetPolicyRefreshIntervalForTests(interval time.Duration) func() {
+	policyRefreshInterval = interval
+	return func() {
+		policyRefreshInterval = policyRefreshIntervalDefault
+	}
+}
+
 func (s *policySource[P, B, E]) Run(ctx context.Context) error {
 	if s.ctx != nil {
 		return fmt.Errorf("policy source already running")
@@ -178,7 +194,7 @@ func (s *policySource[P, B, E]) Run(ctx context.Context) error {
 	// and needs to be recompiled
 	go func() {
 		// Loop every 1 second until context is cancelled, refreshing policies
-		wait.Until(s.refreshPolicies, 1*time.Second, ctx.Done())
+		wait.Until(s.refreshPolicies, policyRefreshInterval, ctx.Done())
 	}()
 
 	<-ctx.Done()

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/generic/policy_test_context.go

@@ -45,7 +45,6 @@ import (
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/apiserver/pkg/admission/initializer"
 	"k8s.io/apiserver/pkg/authorization/authorizer"
-	"k8s.io/apiserver/pkg/features"
 )
 
 // PolicyTestContext is everything you need to unit test a policy plugin
@@ -196,18 +195,6 @@ func NewPolicyTestContext[P, B runtime.Object, E Evaluator](
 	plugin.SetEnabled(true)
 
 	featureGate := featuregate.NewFeatureGate()
-	err = featureGate.Add(map[featuregate.Feature]featuregate.FeatureSpec{
-		//!TODO: move this to validating specific tests
-		features.ValidatingAdmissionPolicy: {
-			Default: true, PreRelease: featuregate.Beta}})
-	if err != nil {
-		return nil, nil, err
-	}
-	err = featureGate.SetFromMap(map[string]bool{string(features.ValidatingAdmissionPolicy): true})
-	if err != nil {
-		return nil, nil, err
-	}
-
 	testContext, testCancel := context.WithCancel(context.Background())
 	genericInitializer := initializer.New(
 		nativeClient,

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/accessor.go

@@ -0,0 +1,144 @@
+/*
+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 mutating
+
+import (
+	v1 "k8s.io/api/admissionregistration/v1"
+	"k8s.io/api/admissionregistration/v1alpha1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/generic"
+)
+
+func NewMutatingAdmissionPolicyAccessor(obj *Policy) generic.PolicyAccessor {
+	return &mutatingAdmissionPolicyAccessor{
+		Policy: obj,
+	}
+}
+
+func NewMutatingAdmissionPolicyBindingAccessor(obj *PolicyBinding) generic.BindingAccessor {
+	return &mutatingAdmissionPolicyBindingAccessor{
+		PolicyBinding: obj,
+	}
+}
+
+type mutatingAdmissionPolicyAccessor struct {
+	*Policy
+}
+
+func (v *mutatingAdmissionPolicyAccessor) GetNamespace() string {
+	return v.Namespace
+}
+
+func (v *mutatingAdmissionPolicyAccessor) GetName() string {
+	return v.Name
+}
+
+func (v *mutatingAdmissionPolicyAccessor) GetParamKind() *v1.ParamKind {
+	pk := v.Spec.ParamKind
+	if pk == nil {
+		return nil
+	}
+	return &v1.ParamKind{
+		APIVersion: pk.APIVersion,
+		Kind:       pk.Kind,
+	}
+}
+
+func (v *mutatingAdmissionPolicyAccessor) GetMatchConstraints() *v1.MatchResources {
+	return convertV1alpha1ResourceRulesToV1(v.Spec.MatchConstraints)
+}
+
+func (v *mutatingAdmissionPolicyAccessor) GetFailurePolicy() *v1.FailurePolicyType {
+	return toV1FailurePolicy(v.Spec.FailurePolicy)
+}
+
+func toV1FailurePolicy(failurePolicy *v1alpha1.FailurePolicyType) *v1.FailurePolicyType {
+	if failurePolicy == nil {
+		return nil
+	}
+	fp := v1.FailurePolicyType(*failurePolicy)
+	return &fp
+}
+
+type mutatingAdmissionPolicyBindingAccessor struct {
+	*PolicyBinding
+}
+
+func (v *mutatingAdmissionPolicyBindingAccessor) GetNamespace() string {
+	return v.Namespace
+}
+
+func (v *mutatingAdmissionPolicyBindingAccessor) GetName() string {
+	return v.Name
+}
+
+func (v *mutatingAdmissionPolicyBindingAccessor) GetPolicyName() types.NamespacedName {
+	return types.NamespacedName{
+		Namespace: "",
+		Name:      v.Spec.PolicyName,
+	}
+}
+
+func (v *mutatingAdmissionPolicyBindingAccessor) GetMatchResources() *v1.MatchResources {
+	return convertV1alpha1ResourceRulesToV1(v.Spec.MatchResources)
+}
+
+func (v *mutatingAdmissionPolicyBindingAccessor) GetParamRef() *v1.ParamRef {
+	if v.Spec.ParamRef == nil {
+		return nil
+	}
+
+	var nfa *v1.ParameterNotFoundActionType
+	if v.Spec.ParamRef.ParameterNotFoundAction != nil {
+		nfa = new(v1.ParameterNotFoundActionType)
+		*nfa = v1.ParameterNotFoundActionType(*v.Spec.ParamRef.ParameterNotFoundAction)
+	}
+
+	return &v1.ParamRef{
+		Name:                    v.Spec.ParamRef.Name,
+		Namespace:               v.Spec.ParamRef.Namespace,
+		Selector:                v.Spec.ParamRef.Selector,
+		ParameterNotFoundAction: nfa,
+	}
+}
+
+func convertV1alpha1ResourceRulesToV1(mc *v1alpha1.MatchResources) *v1.MatchResources {
+	if mc == nil {
+		return nil
+	}
+
+	var res v1.MatchResources
+	res.NamespaceSelector = mc.NamespaceSelector
+	res.ObjectSelector = mc.ObjectSelector
+	for _, ex := range mc.ExcludeResourceRules {
+		res.ExcludeResourceRules = append(res.ExcludeResourceRules, v1.NamedRuleWithOperations{
+			ResourceNames:      ex.ResourceNames,
+			RuleWithOperations: ex.RuleWithOperations,
+		})
+	}
+	for _, ex := range mc.ResourceRules {
+		res.ResourceRules = append(res.ResourceRules, v1.NamedRuleWithOperations{
+			ResourceNames:      ex.ResourceNames,
+			RuleWithOperations: ex.RuleWithOperations,
+		})
+	}
+	if mc.MatchPolicy != nil {
+		mp := v1.MatchPolicyType(*mc.MatchPolicy)
+		res.MatchPolicy = &mp
+	}
+	return &res
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/compilation.go

@@ -0,0 +1,81 @@
+/*
+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 mutating
+
+import (
+	"fmt"
+
+	"k8s.io/api/admissionregistration/v1alpha1"
+	plugincel "k8s.io/apiserver/pkg/admission/plugin/cel"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch"
+	"k8s.io/apiserver/pkg/admission/plugin/webhook/matchconditions"
+	apiservercel "k8s.io/apiserver/pkg/cel"
+	"k8s.io/apiserver/pkg/cel/environment"
+)
+
+// compilePolicy compiles the policy into a PolicyEvaluator
+// any error is stored and delayed until invocation.
+//
+// Each individual mutation is compiled into MutationEvaluationFunc and
+// returned is a PolicyEvaluator in the same order as the mutations appeared in the policy.
+func compilePolicy(policy *Policy) PolicyEvaluator {
+	opts := plugincel.OptionalVariableDeclarations{HasParams: policy.Spec.ParamKind != nil, StrictCost: true, HasAuthorizer: true}
+	compiler, err := plugincel.NewCompositedCompiler(environment.MustBaseEnvSet(environment.DefaultCompatibilityVersion(), true))
+	if err != nil {
+		return PolicyEvaluator{Error: &apiservercel.Error{
+			Type:   apiservercel.ErrorTypeInternal,
+			Detail: fmt.Sprintf("failed to initialize CEL compiler: %v", err),
+		}}
+	}
+
+	// Compile and store variables
+	compiler.CompileAndStoreVariables(convertv1alpha1Variables(policy.Spec.Variables), opts, environment.StoredExpressions)
+
+	// Compile matchers
+	var matcher matchconditions.Matcher = nil
+	matchConditions := policy.Spec.MatchConditions
+	if len(matchConditions) > 0 {
+		matchExpressionAccessors := make([]plugincel.ExpressionAccessor, len(matchConditions))
+		for i := range matchConditions {
+			matchExpressionAccessors[i] = (*matchconditions.MatchCondition)(&matchConditions[i])
+		}
+		matcher = matchconditions.NewMatcher(compiler.CompileCondition(matchExpressionAccessors, opts, environment.StoredExpressions), toV1FailurePolicy(policy.Spec.FailurePolicy), "policy", "validate", policy.Name)
+	}
+
+	// Compiler patchers
+	var patchers []patch.Patcher
+	patchOptions := opts
+	patchOptions.HasPatchTypes = true
+	for _, m := range policy.Spec.Mutations {
+		switch m.PatchType {
+		case v1alpha1.PatchTypeJSONPatch:
+			if m.JSONPatch != nil {
+				accessor := &patch.JSONPatchCondition{Expression: m.JSONPatch.Expression}
+				compileResult := compiler.CompileMutatingEvaluator(accessor, patchOptions, environment.StoredExpressions)
+				patchers = append(patchers, patch.NewJSONPatcher(compileResult))
+			}
+		case v1alpha1.PatchTypeApplyConfiguration:
+			if m.ApplyConfiguration != nil {
+				accessor := &patch.ApplyConfigurationCondition{Expression: m.ApplyConfiguration.Expression}
+				compileResult := compiler.CompileMutatingEvaluator(accessor, patchOptions, environment.StoredExpressions)
+				patchers = append(patchers, patch.NewApplyConfigurationPatcher(compileResult))
+			}
+		}
+	}
+
+	return PolicyEvaluator{Matcher: matcher, Mutators: patchers, CompositionEnv: compiler.CompositionEnv}
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/dispatcher.go

@@ -0,0 +1,295 @@
+/*
+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 mutating
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"k8s.io/api/admissionregistration/v1alpha1"
+	v1 "k8s.io/api/core/v1"
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
+	k8serrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apiserver/pkg/admission"
+	admissionauthorizer "k8s.io/apiserver/pkg/admission/plugin/authorizer"
+	"k8s.io/apiserver/pkg/admission/plugin/cel"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/generic"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/matching"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch"
+	webhookgeneric "k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
+	celconfig "k8s.io/apiserver/pkg/apis/cel"
+	"k8s.io/apiserver/pkg/authorization/authorizer"
+)
+
+func NewDispatcher(a authorizer.Authorizer, m *matching.Matcher, tcm patch.TypeConverterManager) generic.Dispatcher[PolicyHook] {
+	res := &dispatcher{
+		matcher:              m,
+		authz:                a,
+		typeConverterManager: tcm,
+	}
+	res.Dispatcher = generic.NewPolicyDispatcher[*Policy, *PolicyBinding, PolicyEvaluator](
+		NewMutatingAdmissionPolicyAccessor,
+		NewMutatingAdmissionPolicyBindingAccessor,
+		m,
+		res.dispatchInvocations,
+	)
+	return res
+}
+
+type dispatcher struct {
+	matcher              *matching.Matcher
+	authz                authorizer.Authorizer
+	typeConverterManager patch.TypeConverterManager
+	generic.Dispatcher[PolicyHook]
+}
+
+func (d *dispatcher) Start(ctx context.Context) error {
+	go d.typeConverterManager.Run(ctx)
+	return d.Dispatcher.Start(ctx)
+}
+
+func (d *dispatcher) dispatchInvocations(
+	ctx context.Context,
+	a admission.Attributes,
+	o admission.ObjectInterfaces,
+	versionedAttributes webhookgeneric.VersionedAttributeAccessor,
+	invocations []generic.PolicyInvocation[*Policy, *PolicyBinding, PolicyEvaluator],
+) ([]generic.PolicyError, *k8serrors.StatusError) {
+	var lastVersionedAttr *admission.VersionedAttributes
+
+	reinvokeCtx := a.GetReinvocationContext()
+	var policyReinvokeCtx *policyReinvokeContext
+	if v := reinvokeCtx.Value(PluginName); v != nil {
+		policyReinvokeCtx = v.(*policyReinvokeContext)
+	} else {
+		policyReinvokeCtx = &policyReinvokeContext{}
+		reinvokeCtx.SetValue(PluginName, policyReinvokeCtx)
+	}
+
+	if reinvokeCtx.IsReinvoke() && policyReinvokeCtx.IsOutputChangedSinceLastPolicyInvocation(a.GetObject()) {
+		// If the object has changed, we know the in-tree plugin re-invocations have mutated the object,
+		// and we need to reinvoke all eligible policies.
+		policyReinvokeCtx.RequireReinvokingPreviouslyInvokedPlugins()
+	}
+	defer func() {
+		policyReinvokeCtx.SetLastPolicyInvocationOutput(a.GetObject())
+	}()
+
+	var policyErrors []generic.PolicyError
+	addConfigError := func(err error, invocation generic.PolicyInvocation[*Policy, *PolicyBinding, PolicyEvaluator], reason metav1.StatusReason) {
+		policyErrors = append(policyErrors, generic.PolicyError{
+			Message: err,
+			Policy:  NewMutatingAdmissionPolicyAccessor(invocation.Policy),
+			Binding: NewMutatingAdmissionPolicyBindingAccessor(invocation.Binding),
+			Reason:  reason,
+		})
+	}
+
+	// There is at least one invocation to invoke. Make sure we have a namespace
+	// object if the incoming object is not cluster scoped to pass into the evaluator.
+	var namespace *v1.Namespace
+	var err error
+	namespaceName := a.GetNamespace()
+
+	// Special case, the namespace object has the namespace of itself (maybe a bug).
+	// unset it if the incoming object is a namespace
+	if gvk := a.GetKind(); gvk.Kind == "Namespace" && gvk.Version == "v1" && gvk.Group == "" {
+		namespaceName = ""
+	}
+
+	// if it is cluster scoped, namespaceName will be empty
+	// Otherwise, get the Namespace resource.
+	if namespaceName != "" {
+		namespace, err = d.matcher.GetNamespace(namespaceName)
+		if err != nil {
+			return nil, k8serrors.NewNotFound(schema.GroupResource{Group: "", Resource: "namespaces"}, namespaceName)
+		}
+	}
+
+	authz := admissionauthorizer.NewCachingAuthorizer(d.authz)
+
+	// Should loop through invocations, handling possible error and invoking
+	// evaluator to apply patch, also should handle re-invocations
+	for _, invocation := range invocations {
+		if invocation.Evaluator.CompositionEnv != nil {
+			ctx = invocation.Evaluator.CompositionEnv.CreateContext(ctx)
+		}
+		if len(invocation.Evaluator.Mutators) != len(invocation.Policy.Spec.Mutations) {
+			// This would be a bug. The compiler should always return exactly as
+			// many evaluators as there are mutations
+			return nil, k8serrors.NewInternalError(fmt.Errorf("expected %v compiled evaluators for policy %v, got %v",
+				len(invocation.Policy.Spec.Mutations), invocation.Policy.Name, len(invocation.Evaluator.Mutators)))
+		}
+
+		versionedAttr, err := versionedAttributes.VersionedAttribute(invocation.Kind)
+		if err != nil {
+			// This should never happen, we pre-warm versoined attribute
+			// accessors before starting the dispatcher
+			return nil, k8serrors.NewInternalError(err)
+		}
+
+		if invocation.Evaluator.Matcher != nil {
+			matchResults := invocation.Evaluator.Matcher.Match(ctx, versionedAttr, invocation.Param, authz)
+			if matchResults.Error != nil {
+				addConfigError(matchResults.Error, invocation, metav1.StatusReasonInvalid)
+				continue
+			}
+
+			// if preconditions are not met, then skip mutations
+			if !matchResults.Matches {
+				continue
+			}
+		}
+
+		invocationKey, invocationKeyErr := keyFor(invocation)
+		if invocationKeyErr != nil {
+			// This should never happen. It occurs if there is a programming
+			// error causing the Param not to be a valid object.
+			return nil, k8serrors.NewInternalError(invocationKeyErr)
+		}
+		if reinvokeCtx.IsReinvoke() && !policyReinvokeCtx.ShouldReinvoke(invocationKey) {
+			continue
+		}
+
+		objectBeforeMutations := versionedAttr.VersionedObject
+		// Mutations for a single invocation of a MutatingAdmissionPolicy are evaluated
+		// in order.
+		for mutationIndex := range invocation.Policy.Spec.Mutations {
+			lastVersionedAttr = versionedAttr
+			if versionedAttr.VersionedObject == nil { // Do not call patchers if there is no object to patch.
+				continue
+			}
+
+			patcher := invocation.Evaluator.Mutators[mutationIndex]
+			optionalVariables := cel.OptionalVariableBindings{VersionedParams: invocation.Param, Authorizer: authz}
+			err = d.dispatchOne(ctx, patcher, o, versionedAttr, namespace, invocation.Resource, optionalVariables)
+			if err != nil {
+				var statusError *k8serrors.StatusError
+				if errors.As(err, &statusError) {
+					return nil, statusError
+				}
+
+				addConfigError(err, invocation, metav1.StatusReasonInvalid)
+				continue
+			}
+		}
+		if !apiequality.Semantic.DeepEqual(objectBeforeMutations, versionedAttr.VersionedObject) {
+			// The mutation has changed the object. Prepare to reinvoke all previous mutations that are eligible for re-invocation.
+			policyReinvokeCtx.RequireReinvokingPreviouslyInvokedPlugins()
+			reinvokeCtx.SetShouldReinvoke()
+		}
+		if invocation.Policy.Spec.ReinvocationPolicy == v1alpha1.IfNeededReinvocationPolicy {
+			policyReinvokeCtx.AddReinvocablePolicyToPreviouslyInvoked(invocationKey)
+		}
+	}
+
+	if lastVersionedAttr != nil && lastVersionedAttr.VersionedObject != nil && lastVersionedAttr.Dirty {
+		policyReinvokeCtx.RequireReinvokingPreviouslyInvokedPlugins()
+		reinvokeCtx.SetShouldReinvoke()
+		if err := o.GetObjectConvertor().Convert(lastVersionedAttr.VersionedObject, lastVersionedAttr.Attributes.GetObject(), nil); err != nil {
+			return nil, k8serrors.NewInternalError(fmt.Errorf("failed to convert object: %w", err))
+		}
+	}
+
+	return policyErrors, nil
+}
+
+func (d *dispatcher) dispatchOne(
+	ctx context.Context,
+	patcher patch.Patcher,
+	o admission.ObjectInterfaces,
+	versionedAttributes *admission.VersionedAttributes,
+	namespace *v1.Namespace,
+	resource schema.GroupVersionResource,
+	optionalVariables cel.OptionalVariableBindings,
+) (err error) {
+	if patcher == nil {
+		// internal error. this should not happen
+		return k8serrors.NewInternalError(fmt.Errorf("policy evaluator is nil"))
+	}
+
+	// Find type converter for the invoked Group-Version.
+	typeConverter := d.typeConverterManager.GetTypeConverter(versionedAttributes.VersionedKind)
+	if typeConverter == nil {
+		// This can happen if the request is for a resource whose schema
+		// has not been registered with the type converter manager.
+		return k8serrors.NewServiceUnavailable(fmt.Sprintf("Resource kind %s not found. There can be a delay between when CustomResourceDefinitions are created and when they are available.", versionedAttributes.VersionedKind))
+	}
+
+	patchRequest := patch.Request{
+		MatchedResource:     resource,
+		VersionedAttributes: versionedAttributes,
+		ObjectInterfaces:    o,
+		OptionalVariables:   optionalVariables,
+		Namespace:           namespace,
+		TypeConverter:       typeConverter,
+	}
+	newVersionedObject, err := patcher.Patch(ctx, patchRequest, celconfig.RuntimeCELCostBudget)
+	if err != nil {
+		return err
+	}
+
+	switch versionedAttributes.VersionedObject.(type) {
+	case *unstructured.Unstructured:
+		// No conversion needed before defaulting for the patch object if the admitted object is unstructured.
+	default:
+		// Before defaulting, if the admitted object is a typed object, convert unstructured patch result back to a typed object.
+		newVersionedObject, err = o.GetObjectConvertor().ConvertToVersion(newVersionedObject, versionedAttributes.GetKind().GroupVersion())
+		if err != nil {
+			return err
+		}
+	}
+	o.GetObjectDefaulter().Default(newVersionedObject)
+
+	versionedAttributes.Dirty = true
+	versionedAttributes.VersionedObject = newVersionedObject
+	return nil
+}
+
+func keyFor(invocation generic.PolicyInvocation[*Policy, *PolicyBinding, PolicyEvaluator]) (key, error) {
+	var paramUID types.NamespacedName
+	if invocation.Param != nil {
+		paramAccessor, err := meta.Accessor(invocation.Param)
+		if err != nil {
+			// This should never happen, as the param should have been validated
+			// before being passed to the plugin.
+			return key{}, err
+		}
+		paramUID = types.NamespacedName{
+			Name:      paramAccessor.GetName(),
+			Namespace: paramAccessor.GetNamespace(),
+		}
+	}
+
+	return key{
+		PolicyUID: types.NamespacedName{
+			Name:      invocation.Policy.GetName(),
+			Namespace: invocation.Policy.GetNamespace(),
+		},
+		BindingUID: types.NamespacedName{
+			Name:      invocation.Binding.GetName(),
+			Namespace: invocation.Binding.GetNamespace(),
+		},
+		ParamUID: paramUID,
+	}, nil
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch/interface.go

@@ -0,0 +1,45 @@
+/*
+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 patch
+
+import (
+	"context"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/managedfields"
+	"k8s.io/apiserver/pkg/admission"
+	"k8s.io/apiserver/pkg/admission/plugin/cel"
+)
+
+// Patcher provides a patch function to perform a mutation to an object in the admission chain.
+type Patcher interface {
+	// Patch returns a copy of the object in the request, modified to change specified by the patch.
+	// The original object in the request MUST NOT be modified in-place.
+	Patch(ctx context.Context, request Request, runtimeCELCostBudget int64) (runtime.Object, error)
+}
+
+// Request defines the arguments required by a patcher.
+type Request struct {
+	MatchedResource     schema.GroupVersionResource
+	VersionedAttributes *admission.VersionedAttributes
+	ObjectInterfaces    admission.ObjectInterfaces
+	OptionalVariables   cel.OptionalVariableBindings
+	Namespace           *v1.Namespace
+	TypeConverter       managedfields.TypeConverter
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch/json_patch.go

@@ -0,0 +1,192 @@
+/*
+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 patch
+
+import (
+	"context"
+	gojson "encoding/json"
+	"errors"
+	"fmt"
+	celgo "github.com/google/cel-go/cel"
+	"reflect"
+	"strconv"
+
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/common/types/traits"
+	"google.golang.org/protobuf/types/known/structpb"
+	jsonpatch "gopkg.in/evanphx/json-patch.v4"
+
+	admissionv1 "k8s.io/api/admission/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/serializer/json"
+	plugincel "k8s.io/apiserver/pkg/admission/plugin/cel"
+	"k8s.io/apiserver/pkg/cel/mutation"
+	"k8s.io/apiserver/pkg/cel/mutation/dynamic"
+	pointer "k8s.io/utils/ptr"
+)
+
+// JSONPatchCondition contains the inputs needed to compile and evaluate a cel expression
+// that returns a JSON patch value.
+type JSONPatchCondition struct {
+	Expression string
+}
+
+var _ plugincel.ExpressionAccessor = &JSONPatchCondition{}
+
+func (v *JSONPatchCondition) GetExpression() string {
+	return v.Expression
+}
+
+func (v *JSONPatchCondition) ReturnTypes() []*celgo.Type {
+	return []*celgo.Type{celgo.ListType(jsonPatchType)}
+}
+
+var jsonPatchType = types.NewObjectType("JSONPatch")
+
+// NewJSONPatcher creates a patcher that performs a JSON Patch mutation.
+func NewJSONPatcher(patchEvaluator plugincel.MutatingEvaluator) Patcher {
+	return &jsonPatcher{patchEvaluator}
+}
+
+type jsonPatcher struct {
+	PatchEvaluator plugincel.MutatingEvaluator
+}
+
+func (e *jsonPatcher) Patch(ctx context.Context, r Request, runtimeCELCostBudget int64) (runtime.Object, error) {
+	admissionRequest := plugincel.CreateAdmissionRequest(
+		r.VersionedAttributes.Attributes,
+		metav1.GroupVersionResource(r.MatchedResource),
+		metav1.GroupVersionKind(r.VersionedAttributes.VersionedKind))
+
+	compileErrors := e.PatchEvaluator.CompilationErrors()
+	if len(compileErrors) > 0 {
+		return nil, errors.Join(compileErrors...)
+	}
+	patchObj, _, err := e.evaluatePatchExpression(ctx, e.PatchEvaluator, runtimeCELCostBudget, r, admissionRequest)
+	if err != nil {
+		return nil, err
+	}
+	o := r.ObjectInterfaces
+	jsonSerializer := json.NewSerializerWithOptions(json.DefaultMetaFactory, o.GetObjectCreater(), o.GetObjectTyper(), json.SerializerOptions{Pretty: false, Strict: true})
+	objJS, err := runtime.Encode(jsonSerializer, r.VersionedAttributes.VersionedObject)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create JSON patch: %w", err)
+	}
+	patchedJS, err := patchObj.Apply(objJS)
+	if err != nil {
+		if errors.Is(err, jsonpatch.ErrTestFailed) {
+			// If a json patch fails a test operation, the patch must not be applied
+			return r.VersionedAttributes.VersionedObject, nil
+		}
+		return nil, fmt.Errorf("JSON Patch: %w", err)
+	}
+
+	var newVersionedObject runtime.Object
+	if _, ok := r.VersionedAttributes.VersionedObject.(*unstructured.Unstructured); ok {
+		newVersionedObject = &unstructured.Unstructured{}
+	} else {
+		newVersionedObject, err = o.GetObjectCreater().New(r.VersionedAttributes.VersionedKind)
+		if err != nil {
+			return nil, apierrors.NewInternalError(err)
+		}
+	}
+
+	if newVersionedObject, _, err = jsonSerializer.Decode(patchedJS, nil, newVersionedObject); err != nil {
+		return nil, apierrors.NewInternalError(err)
+	}
+
+	return newVersionedObject, nil
+}
+
+func (e *jsonPatcher) evaluatePatchExpression(ctx context.Context, patchEvaluator plugincel.MutatingEvaluator, remainingBudget int64, r Request, admissionRequest *admissionv1.AdmissionRequest) (jsonpatch.Patch, int64, error) {
+	var err error
+	var eval plugincel.EvaluationResult
+	eval, remainingBudget, err = patchEvaluator.ForInput(ctx, r.VersionedAttributes, admissionRequest, r.OptionalVariables, r.Namespace, remainingBudget)
+	if err != nil {
+		return nil, -1, err
+	}
+	if eval.Error != nil {
+		return nil, -1, eval.Error
+	}
+	refVal := eval.EvalResult
+
+	// the return type can be any valid CEL value.
+	// Scalars, maps and lists are used to set the value when the path points to a field of that type.
+	// ObjectVal is used when the path points to a struct. A map like "{"field1": 1, "fieldX": bool}" is not
+	// possible in Kubernetes CEL because maps and lists may not have mixed types.
+
+	iter, ok := refVal.(traits.Lister)
+	if !ok {
+		// Should never happen since compiler checks return type.
+		return nil, -1, fmt.Errorf("type mismatch: JSONPatchType.expression should evaluate to array")
+	}
+	result := jsonpatch.Patch{}
+	for it := iter.Iterator(); it.HasNext() == types.True; {
+		v := it.Next()
+		patchObj, err := v.ConvertToNative(reflect.TypeOf(&mutation.JSONPatchVal{}))
+		if err != nil {
+			// Should never happen since return type is checked by compiler.
+			return nil, -1, fmt.Errorf("type mismatch: JSONPatchType.expression should evaluate to array of JSONPatch: %w", err)
+		}
+		op, ok := patchObj.(*mutation.JSONPatchVal)
+		if !ok {
+			// Should never happen since return type is checked by compiler.
+			return nil, -1, fmt.Errorf("type mismatch: JSONPatchType.expression should evaluate to array of JSONPatch, got element of %T", patchObj)
+		}
+
+		// Construct a JSON Patch from the evaluated CEL expression
+		resultOp := jsonpatch.Operation{}
+		resultOp["op"] = pointer.To(gojson.RawMessage(strconv.Quote(op.Op)))
+		resultOp["path"] = pointer.To(gojson.RawMessage(strconv.Quote(op.Path)))
+		if len(op.From) > 0 {
+			resultOp["from"] = pointer.To(gojson.RawMessage(strconv.Quote(op.From)))
+		}
+		if op.Val != nil {
+			if objVal, ok := op.Val.(*dynamic.ObjectVal); ok {
+				// TODO: Object initializers are insufficiently type checked.
+				// In the interim, we use this sanity check to detect type mismatches
+				// between field names and Object initializers. For example,
+				// "Object.spec{ selector: Object.spec.wrong{}}" is detected as a mismatch.
+				// Before beta, attaching full type information both to Object initializers and
+				// the "object" and "oldObject" variables is needed. This will allow CEL to
+				// perform comprehensive runtime type checking.
+				err := objVal.CheckTypeNamesMatchFieldPathNames()
+				if err != nil {
+					return nil, -1, fmt.Errorf("type mismatch: %w", err)
+				}
+			}
+			// CEL data literals representing arbitrary JSON values can be serialized to JSON for use in
+			// JSON Patch if first converted to pb.Value.
+			v, err := op.Val.ConvertToNative(reflect.TypeOf(&structpb.Value{}))
+			if err != nil {
+				return nil, -1, fmt.Errorf("JSONPath valueExpression evaluated to a type that could not marshal to JSON: %w", err)
+			}
+			b, err := gojson.Marshal(v)
+			if err != nil {
+				return nil, -1, fmt.Errorf("JSONPath valueExpression evaluated to a type that could not marshal to JSON: %w", err)
+			}
+			resultOp["value"] = pointer.To[gojson.RawMessage](b)
+		}
+
+		result = append(result, resultOp)
+	}
+
+	return result, remainingBudget, nil
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch/smd.go

@@ -0,0 +1,217 @@
+/*
+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 patch
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	celgo "github.com/google/cel-go/cel"
+	celtypes "github.com/google/cel-go/common/types"
+	"strings"
+
+	"sigs.k8s.io/structured-merge-diff/v4/fieldpath"
+	"sigs.k8s.io/structured-merge-diff/v4/schema"
+	"sigs.k8s.io/structured-merge-diff/v4/typed"
+	"sigs.k8s.io/structured-merge-diff/v4/value"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/managedfields"
+	plugincel "k8s.io/apiserver/pkg/admission/plugin/cel"
+	"k8s.io/apiserver/pkg/cel/mutation/dynamic"
+)
+
+// ApplyConfigurationCondition contains the inputs needed to compile and evaluate a cel expression
+// that returns an apply configuration
+type ApplyConfigurationCondition struct {
+	Expression string
+}
+
+var _ plugincel.ExpressionAccessor = &ApplyConfigurationCondition{}
+
+func (v *ApplyConfigurationCondition) GetExpression() string {
+	return v.Expression
+}
+
+func (v *ApplyConfigurationCondition) ReturnTypes() []*celgo.Type {
+	return []*celgo.Type{applyConfigObjectType}
+}
+
+var applyConfigObjectType = celtypes.NewObjectType("Object")
+
+// NewApplyConfigurationPatcher creates a patcher that performs an applyConfiguration mutation.
+func NewApplyConfigurationPatcher(expressionEvaluator plugincel.MutatingEvaluator) Patcher {
+	return &applyConfigPatcher{expressionEvaluator: expressionEvaluator}
+}
+
+type applyConfigPatcher struct {
+	expressionEvaluator plugincel.MutatingEvaluator
+}
+
+func (e *applyConfigPatcher) Patch(ctx context.Context, r Request, runtimeCELCostBudget int64) (runtime.Object, error) {
+	admissionRequest := plugincel.CreateAdmissionRequest(
+		r.VersionedAttributes.Attributes,
+		metav1.GroupVersionResource(r.MatchedResource),
+		metav1.GroupVersionKind(r.VersionedAttributes.VersionedKind))
+
+	compileErrors := e.expressionEvaluator.CompilationErrors()
+	if len(compileErrors) > 0 {
+		return nil, errors.Join(compileErrors...)
+	}
+	eval, _, err := e.expressionEvaluator.ForInput(ctx, r.VersionedAttributes, admissionRequest, r.OptionalVariables, r.Namespace, runtimeCELCostBudget)
+	if err != nil {
+		return nil, err
+	}
+	if eval.Error != nil {
+		return nil, eval.Error
+	}
+	v := eval.EvalResult
+
+	// The compiler ensures that the return type is an ObjectVal with type name of "Object".
+	objVal, ok := v.(*dynamic.ObjectVal)
+	if !ok {
+		// Should not happen since the compiler type checks the return type.
+		return nil, fmt.Errorf("unsupported return type from ApplyConfiguration expression: %v", v.Type())
+	}
+	// TODO: Object initializers are insufficiently type checked.
+	// In the interim, we use this sanity check to detect type mismatches
+	// between field names and Object initializers. For example,
+	// "Object.spec{ selector: Object.spec.wrong{}}" is detected as a mismatch.
+	// Before beta, attaching full type information both to Object initializers and
+	// the "object" and "oldObject" variables is needed. This will allow CEL to
+	// perform comprehensive runtime type checking.
+	err = objVal.CheckTypeNamesMatchFieldPathNames()
+	if err != nil {
+		return nil, fmt.Errorf("type mismatch: %w", err)
+	}
+
+	value, ok := objVal.Value().(map[string]any)
+	if !ok {
+		return nil, fmt.Errorf("invalid return type: %T", v)
+	}
+
+	patchObject := unstructured.Unstructured{Object: value}
+	patchObject.SetGroupVersionKind(r.VersionedAttributes.VersionedObject.GetObjectKind().GroupVersionKind())
+	patched, err := ApplyStructuredMergeDiff(r.TypeConverter, r.VersionedAttributes.VersionedObject, &patchObject)
+	if err != nil {
+		return nil, fmt.Errorf("error applying patch: %w", err)
+	}
+	return patched, nil
+}
+
+// ApplyStructuredMergeDiff applies a structured merge diff to an object and returns a copy of the object
+// with the patch applied.
+func ApplyStructuredMergeDiff(
+	typeConverter managedfields.TypeConverter,
+	originalObject runtime.Object,
+	patch *unstructured.Unstructured,
+) (runtime.Object, error) {
+	if patch.GroupVersionKind() != originalObject.GetObjectKind().GroupVersionKind() {
+		return nil, fmt.Errorf("patch (%v) and original object (%v) are not of the same gvk", patch.GroupVersionKind().String(), originalObject.GetObjectKind().GroupVersionKind().String())
+	} else if typeConverter == nil {
+		return nil, fmt.Errorf("type converter must not be nil")
+	}
+
+	patchObjTyped, err := typeConverter.ObjectToTyped(patch)
+	if err != nil {
+		return nil, fmt.Errorf("failed to convert patch object to typed object: %w", err)
+	}
+
+	err = validatePatch(patchObjTyped)
+	if err != nil {
+		return nil, fmt.Errorf("invalid ApplyConfiguration: %w", err)
+	}
+
+	liveObjTyped, err := typeConverter.ObjectToTyped(originalObject)
+	if err != nil {
+		return nil, fmt.Errorf("failed to convert original object to typed object: %w", err)
+	}
+
+	newObjTyped, err := liveObjTyped.Merge(patchObjTyped)
+	if err != nil {
+		return nil, fmt.Errorf("failed to merge patch: %w", err)
+	}
+
+	// Our mutating admission policy sets the fields but does not track ownership.
+	// Newly introduced fields in the patch won't be tracked by a field manager
+	// (so if the original object is updated again but the mutating policy is
+	// not active, the fields will be dropped).
+	//
+	// This necessarily means that changes to an object by a mutating policy
+	// are only preserved if the policy was active at the time of the change.
+	// (If the policy is not active, the changes may be dropped.)
+
+	newObj, err := typeConverter.TypedToObject(newObjTyped)
+	if err != nil {
+		return nil, fmt.Errorf("failed to convert typed object to object: %w", err)
+	}
+
+	return newObj, nil
+}
+
+// validatePatch searches an apply configuration for any arrays, maps or structs elements that are atomic and returns
+// an error if any are found.
+// This prevents accidental removal of fields that can occur when the user intends to modify some
+// fields in an atomic type, not realizing that all fields not explicitly set in the new value
+// of the atomic will be removed.
+func validatePatch(v *typed.TypedValue) error {
+	atomics := findAtomics(nil, v.Schema(), v.TypeRef(), v.AsValue())
+	if len(atomics) > 0 {
+		return fmt.Errorf("may not mutate atomic arrays, maps or structs: %v", strings.Join(atomics, ", "))
+	}
+	return nil
+}
+
+// findAtomics returns field paths for any atomic arrays, maps or structs found when traversing the given value.
+func findAtomics(path []fieldpath.PathElement, s *schema.Schema, tr schema.TypeRef, v value.Value) (atomics []string) {
+	if a, ok := s.Resolve(tr); ok { // Validation pass happens before this and checks that all schemas can be resolved
+		if v.IsMap() && a.Map != nil {
+			if a.Map.ElementRelationship == schema.Atomic {
+				atomics = append(atomics, pathString(path))
+			}
+			v.AsMap().Iterate(func(key string, val value.Value) bool {
+				pe := fieldpath.PathElement{FieldName: &key}
+				if sf, ok := a.Map.FindField(key); ok {
+					tr = sf.Type
+					atomics = append(atomics, findAtomics(append(path, pe), s, tr, val)...)
+				}
+				return true
+			})
+		}
+		if v.IsList() && a.List != nil {
+			if a.List.ElementRelationship == schema.Atomic {
+				atomics = append(atomics, pathString(path))
+			}
+			list := v.AsList()
+			for i := 0; i < list.Length(); i++ {
+				pe := fieldpath.PathElement{Index: &i}
+				atomics = append(atomics, findAtomics(append(path, pe), s, a.List.ElementType, list.At(i))...)
+			}
+		}
+	}
+	return atomics
+}
+
+func pathString(path []fieldpath.PathElement) string {
+	sb := strings.Builder{}
+	for _, p := range path {
+		sb.WriteString(p.String())
+	}
+	return sb.String()
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch/typeconverter.go

@@ -0,0 +1,187 @@
+/*
+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 patch
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/managedfields"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/openapi"
+	"k8s.io/kube-openapi/pkg/spec3"
+)
+
+type TypeConverterManager interface {
+	// GetTypeConverter returns a type converter for the given GVK
+	GetTypeConverter(gvk schema.GroupVersionKind) managedfields.TypeConverter
+	Run(ctx context.Context)
+}
+
+func NewTypeConverterManager(
+	staticTypeConverter managedfields.TypeConverter,
+	openapiClient openapi.Client,
+) TypeConverterManager {
+	return &typeConverterManager{
+		staticTypeConverter: staticTypeConverter,
+		openapiClient:       openapiClient,
+		typeConverterMap:    make(map[schema.GroupVersion]typeConverterCacheEntry),
+		lastFetchedPaths:    make(map[schema.GroupVersion]openapi.GroupVersion),
+	}
+}
+
+type typeConverterCacheEntry struct {
+	typeConverter managedfields.TypeConverter
+	entry         openapi.GroupVersion
+}
+
+// typeConverterManager helps us make sure we have an up to date schema and
+// type converter for our openapi models. It should be connfigured to use a
+// static type converter for natively typed schemas, and fetches the schema
+// for CRDs/other over the network on demand (trying to reduce network calls where necessary)
+type typeConverterManager struct {
+	// schemaCache is used to cache the schema for a given GVK
+	staticTypeConverter managedfields.TypeConverter
+
+	// discoveryClient is used to fetch the schema for a given GVK
+	openapiClient openapi.Client
+
+	lock sync.RWMutex
+
+	typeConverterMap map[schema.GroupVersion]typeConverterCacheEntry
+	lastFetchedPaths map[schema.GroupVersion]openapi.GroupVersion
+}
+
+func (t *typeConverterManager) Run(ctx context.Context) {
+	// Loop every 5s refershing the OpenAPI schema list to know which
+	// schemas have been invalidated. This should use e-tags under the hood
+	_ = wait.PollUntilContextCancel(ctx, 5*time.Second, true, func(_ context.Context) (done bool, err error) {
+		paths, err := t.openapiClient.Paths()
+		if err != nil {
+			utilruntime.HandleError(fmt.Errorf("failed to fetch openapi paths: %w", err))
+			return false, nil
+		}
+
+		// The /openapi/v3 endpoint contains a list of paths whose ServerRelativeURL
+		// value changes every time the schema is updated. So we poll /openapi/v3
+		// to get the "version number" for each schema, and invalidate our cache
+		// if the version number has changed since we pulled it.
+		parsedPaths := make(map[schema.GroupVersion]openapi.GroupVersion, len(paths))
+		for path, entry := range paths {
+			if !strings.HasPrefix(path, "apis/") && !strings.HasPrefix(path, "api/") {
+				continue
+			}
+			path = strings.TrimPrefix(path, "apis/")
+			path = strings.TrimPrefix(path, "api/")
+
+			gv, err := schema.ParseGroupVersion(path)
+			if err != nil {
+				utilruntime.HandleError(fmt.Errorf("failed to parse group version %q: %w", path, err))
+				return false, nil
+			}
+
+			parsedPaths[gv] = entry
+		}
+
+		t.lock.Lock()
+		defer t.lock.Unlock()
+		t.lastFetchedPaths = parsedPaths
+		return false, nil
+	})
+}
+
+func (t *typeConverterManager) GetTypeConverter(gvk schema.GroupVersionKind) managedfields.TypeConverter {
+	// Check to see if the static type converter handles this GVK
+	if t.staticTypeConverter != nil {
+		//!TODO: Add ability to check existence to type converter
+		// working around for now but seeing if getting a typed version of an
+		// empty object returns error
+		stub := &unstructured.Unstructured{}
+		stub.SetGroupVersionKind(gvk)
+
+		if _, err := t.staticTypeConverter.ObjectToTyped(stub); err == nil {
+			return t.staticTypeConverter
+		}
+	}
+
+	gv := gvk.GroupVersion()
+
+	existing, entry, err := func() (managedfields.TypeConverter, openapi.GroupVersion, error) {
+		t.lock.RLock()
+		defer t.lock.RUnlock()
+
+		// If schema is not supported by static type converter, ask discovery
+		// for the schema
+		entry, ok := t.lastFetchedPaths[gv]
+		if !ok {
+			// If we can't get the schema, we can't do anything
+			return nil, nil, fmt.Errorf("no schema for %v", gvk)
+		}
+
+		// If the entry schema has not changed, used the same type converter
+		if existing, ok := t.typeConverterMap[gv]; ok && existing.entry.ServerRelativeURL() == entry.ServerRelativeURL() {
+			// If we have a type converter for this GVK, return it
+			return existing.typeConverter, existing.entry, nil
+		}
+
+		return nil, entry, nil
+	}()
+	if err != nil {
+		utilruntime.HandleError(err)
+		return nil
+	} else if existing != nil {
+		return existing
+	}
+
+	schBytes, err := entry.Schema(runtime.ContentTypeJSON)
+	if err != nil {
+		utilruntime.HandleError(fmt.Errorf("failed to get schema for %v: %w", gvk, err))
+		return nil
+	}
+
+	var sch spec3.OpenAPI
+	if err := json.Unmarshal(schBytes, &sch); err != nil {
+		utilruntime.HandleError(fmt.Errorf("failed to unmarshal schema for %v: %w", gvk, err))
+		return nil
+	}
+
+	// The schema has changed, or there is no entry for it, generate
+	// a new type converter for this GV
+	tc, err := managedfields.NewTypeConverter(sch.Components.Schemas, false)
+	if err != nil {
+		utilruntime.HandleError(fmt.Errorf("failed to create type converter for %v: %w", gvk, err))
+		return nil
+	}
+
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	t.typeConverterMap[gv] = typeConverterCacheEntry{
+		typeConverter: tc,
+		entry:         entry,
+	}
+
+	return tc
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/plugin.go

@@ -0,0 +1,151 @@
+/*
+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 mutating
+
+import (
+	"context"
+	celgo "github.com/google/cel-go/cel"
+	"io"
+
+	"k8s.io/api/admissionregistration/v1alpha1"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/managedfields"
+	"k8s.io/apiserver/pkg/admission"
+	"k8s.io/apiserver/pkg/admission/plugin/cel"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/generic"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/matching"
+	"k8s.io/apiserver/pkg/admission/plugin/policy/mutating/patch"
+	"k8s.io/apiserver/pkg/admission/plugin/webhook/matchconditions"
+	"k8s.io/apiserver/pkg/authorization/authorizer"
+	"k8s.io/apiserver/pkg/features"
+	"k8s.io/client-go/dynamic"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/component-base/featuregate"
+)
+
+const (
+	// PluginName indicates the name of admission plug-in
+	PluginName = "MutatingAdmissionPolicy"
+)
+
+// Register registers a plugin
+func Register(plugins *admission.Plugins) {
+	plugins.Register(PluginName, func(configFile io.Reader) (admission.Interface, error) {
+		return NewPlugin(configFile), nil
+	})
+}
+
+type Policy = v1alpha1.MutatingAdmissionPolicy
+type PolicyBinding = v1alpha1.MutatingAdmissionPolicyBinding
+type PolicyMutation = v1alpha1.Mutation
+type PolicyHook = generic.PolicyHook[*Policy, *PolicyBinding, PolicyEvaluator]
+
+type Mutator struct {
+}
+type MutationEvaluationFunc func(
+	ctx context.Context,
+	matchedResource schema.GroupVersionResource,
+	versionedAttr *admission.VersionedAttributes,
+	o admission.ObjectInterfaces,
+	versionedParams runtime.Object,
+	namespace *corev1.Namespace,
+	typeConverter managedfields.TypeConverter,
+	runtimeCELCostBudget int64,
+	authorizer authorizer.Authorizer,
+) (runtime.Object, error)
+
+type PolicyEvaluator struct {
+	Matcher        matchconditions.Matcher
+	Mutators       []patch.Patcher
+	CompositionEnv *cel.CompositionEnv
+	Error          error
+}
+
+// Plugin is an implementation of admission.Interface.
+type Plugin struct {
+	*generic.Plugin[PolicyHook]
+}
+
+var _ admission.Interface = &Plugin{}
+var _ admission.MutationInterface = &Plugin{}
+
+// NewPlugin returns a generic admission webhook plugin.
+func NewPlugin(_ io.Reader) *Plugin {
+	// There is no request body to mutate for DELETE, so this plugin never handles that operation.
+	handler := admission.NewHandler(admission.Create, admission.Update, admission.Connect)
+	res := &Plugin{}
+	res.Plugin = generic.NewPlugin(
+		handler,
+		func(f informers.SharedInformerFactory, client kubernetes.Interface, dynamicClient dynamic.Interface, restMapper meta.RESTMapper) generic.Source[PolicyHook] {
+			return generic.NewPolicySource(
+				f.Admissionregistration().V1alpha1().MutatingAdmissionPolicies().Informer(),
+				f.Admissionregistration().V1alpha1().MutatingAdmissionPolicyBindings().Informer(),
+				NewMutatingAdmissionPolicyAccessor,
+				NewMutatingAdmissionPolicyBindingAccessor,
+				compilePolicy,
+				//!TODO: Create a way to share param informers between
+				// mutating/validating plugins
+				f,
+				dynamicClient,
+				restMapper,
+			)
+		},
+		func(a authorizer.Authorizer, m *matching.Matcher, client kubernetes.Interface) generic.Dispatcher[PolicyHook] {
+			return NewDispatcher(a, m, patch.NewTypeConverterManager(nil, client.Discovery().OpenAPIV3()))
+		},
+	)
+	return res
+}
+
+// Admit makes an admission decision based on the request attributes.
+func (a *Plugin) Admit(ctx context.Context, attr admission.Attributes, o admission.ObjectInterfaces) error {
+	return a.Plugin.Dispatch(ctx, attr, o)
+}
+
+func (a *Plugin) InspectFeatureGates(featureGates featuregate.FeatureGate) {
+	a.Plugin.SetEnabled(featureGates.Enabled(features.MutatingAdmissionPolicy))
+}
+
+// Variable is a named expression for composition.
+type Variable struct {
+	Name       string
+	Expression string
+}
+
+func (v *Variable) GetExpression() string {
+	return v.Expression
+}
+
+func (v *Variable) ReturnTypes() []*celgo.Type {
+	return []*celgo.Type{celgo.AnyType, celgo.DynType}
+}
+
+func (v *Variable) GetName() string {
+	return v.Name
+}
+
+func convertv1alpha1Variables(variables []v1alpha1.Variable) []cel.NamedExpressionAccessor {
+	namedExpressions := make([]cel.NamedExpressionAccessor, len(variables))
+	for i, variable := range variables {
+		namedExpressions[i] = &Variable{Name: variable.Name, Expression: variable.Expression}
+	}
+	return namedExpressions
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/mutating/reinvocationcontext.go

@@ -0,0 +1,76 @@
+/*
+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 mutating
+
+import (
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/sets"
+)
+
+type key struct {
+	PolicyUID     types.NamespacedName
+	BindingUID    types.NamespacedName
+	ParamUID      types.NamespacedName
+	MutationIndex int
+}
+
+type policyReinvokeContext struct {
+	// lastPolicyOutput holds the result of the last Policy admission plugin call
+	lastPolicyOutput runtime.Object
+	// previouslyInvokedReinvocablePolicys holds the set of policies that have been invoked and
+	// should be reinvoked if a later mutation occurs
+	previouslyInvokedReinvocablePolicies sets.Set[key]
+	// reinvokePolicies holds the set of Policies that should be reinvoked
+	reinvokePolicies sets.Set[key]
+}
+
+func (rc *policyReinvokeContext) ShouldReinvoke(policy key) bool {
+	return rc.reinvokePolicies.Has(policy)
+}
+
+func (rc *policyReinvokeContext) IsOutputChangedSinceLastPolicyInvocation(object runtime.Object) bool {
+	return !apiequality.Semantic.DeepEqual(rc.lastPolicyOutput, object)
+}
+
+func (rc *policyReinvokeContext) SetLastPolicyInvocationOutput(object runtime.Object) {
+	if object == nil {
+		rc.lastPolicyOutput = nil
+		return
+	}
+	rc.lastPolicyOutput = object.DeepCopyObject()
+}
+
+func (rc *policyReinvokeContext) AddReinvocablePolicyToPreviouslyInvoked(policy key) {
+	if rc.previouslyInvokedReinvocablePolicies == nil {
+		rc.previouslyInvokedReinvocablePolicies = sets.New[key]()
+	}
+	rc.previouslyInvokedReinvocablePolicies.Insert(policy)
+}
+
+func (rc *policyReinvokeContext) RequireReinvokingPreviouslyInvokedPlugins() {
+	if len(rc.previouslyInvokedReinvocablePolicies) > 0 {
+		if rc.reinvokePolicies == nil {
+			rc.reinvokePolicies = sets.New[key]()
+		}
+		for s := range rc.previouslyInvokedReinvocablePolicies {
+			rc.reinvokePolicies.Insert(s)
+		}
+		rc.previouslyInvokedReinvocablePolicies = sets.New[key]()
+	}
+}

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/validating/accessor.go

@@ -54,6 +54,10 @@ func (v *validatingAdmissionPolicyAccessor) GetMatchConstraints() *v1.MatchResou
 	return v.Spec.MatchConstraints
 }
 
+func (v *validatingAdmissionPolicyAccessor) GetFailurePolicy() *v1.FailurePolicyType {
+	return v.Spec.FailurePolicy
+}
+
 type validatingAdmissionPolicyBindingAccessor struct {
 	*v1.ValidatingAdmissionPolicyBinding
 }

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/validating/dispatcher.go

@@ -30,6 +30,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	utiljson "k8s.io/apimachinery/pkg/util/json"
 	"k8s.io/apiserver/pkg/admission"
+	admissionauthorizer "k8s.io/apiserver/pkg/admission/plugin/authorizer"
 	"k8s.io/apiserver/pkg/admission/plugin/policy/generic"
 	celmetrics "k8s.io/apiserver/pkg/admission/plugin/policy/validating/metrics"
 	celconfig "k8s.io/apiserver/pkg/apis/cel"
@@ -63,6 +64,10 @@ type policyDecisionWithMetadata struct {
 	Binding    *admissionregistrationv1.ValidatingAdmissionPolicyBinding
 }
 
+func (c *dispatcher) Start(ctx context.Context) error {
+	return nil
+}
+
 // Dispatch implements generic.Dispatcher.
 func (c *dispatcher) Dispatch(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces, hooks []PolicyHook) error {
 
@@ -109,7 +114,7 @@ func (c *dispatcher) Dispatch(ctx context.Context, a admission.Attributes, o adm
 		}
 	}
 
-	authz := newCachingAuthorizer(c.authz)
+	authz := admissionauthorizer.NewCachingAuthorizer(c.authz)
 
 	for _, hook := range hooks {
 		// versionedAttributes will be set to non-nil inside of the loop, but

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/validating/metrics/errors.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package cel
+package metrics
 
 import (
 	"errors"

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/validating/metrics/metrics.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package cel
+package metrics
 
 import (
 	"context"

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/validating/plugin.go

@@ -36,7 +36,6 @@ import (
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
-	"k8s.io/component-base/featuregate"
 )
 
 const (
@@ -93,13 +92,12 @@ type Plugin struct {
 
 var _ admission.Interface = &Plugin{}
 var _ admission.ValidationInterface = &Plugin{}
-var _ initializer.WantsFeatures = &Plugin{}
 var _ initializer.WantsExcludedAdmissionResources = &Plugin{}
 
 func NewPlugin(_ io.Reader) *Plugin {
 	handler := admission.NewHandler(admission.Connect, admission.Create, admission.Delete, admission.Update)
 
-	return &Plugin{
+	p := &Plugin{
 		Plugin: generic.NewPlugin(
 			handler,
 			func(f informers.SharedInformerFactory, client kubernetes.Interface, dynamicClient dynamic.Interface, restMapper meta.RESTMapper) generic.Source[PolicyHook] {
@@ -114,11 +112,13 @@ func NewPlugin(_ io.Reader) *Plugin {
 					restMapper,
 				)
 			},
-			func(a authorizer.Authorizer, m *matching.Matcher) generic.Dispatcher[PolicyHook] {
+			func(a authorizer.Authorizer, m *matching.Matcher, client kubernetes.Interface) generic.Dispatcher[PolicyHook] {
 				return NewDispatcher(a, generic.NewPolicyMatcher(m))
 			},
 		),
 	}
+	p.SetEnabled(true)
+	return p
 }
 
 // Validate makes an admission decision based on the request attributes.
@@ -126,10 +126,6 @@ func (a *Plugin) Validate(ctx context.Context, attr admission.Attributes, o admi
 	return a.Plugin.Dispatch(ctx, attr, o)
 }
 
-func (a *Plugin) InspectFeatureGates(featureGates featuregate.FeatureGate) {
-	a.Plugin.SetEnabled(featureGates.Enabled(features.ValidatingAdmissionPolicy))
-}
-
 func compilePolicy(policy *Policy) Validator {
 	hasParam := false
 	if policy.Spec.ParamKind != nil {
@@ -155,13 +151,13 @@ func compilePolicy(policy *Policy) Validator {
 		for i := range matchConditions {
 			matchExpressionAccessors[i] = (*matchconditions.MatchCondition)(&matchConditions[i])
 		}
-		matcher = matchconditions.NewMatcher(filterCompiler.Compile(matchExpressionAccessors, optionalVars, environment.StoredExpressions), failurePolicy, "policy", "validate", policy.Name)
+		matcher = matchconditions.NewMatcher(filterCompiler.CompileCondition(matchExpressionAccessors, optionalVars, environment.StoredExpressions), failurePolicy, "policy", "validate", policy.Name)
 	}
 	res := NewValidator(
-		filterCompiler.Compile(convertv1Validations(policy.Spec.Validations), optionalVars, environment.StoredExpressions),
+		filterCompiler.CompileCondition(convertv1Validations(policy.Spec.Validations), optionalVars, environment.StoredExpressions),
 		matcher,
-		filterCompiler.Compile(convertv1AuditAnnotations(policy.Spec.AuditAnnotations), optionalVars, environment.StoredExpressions),
-		filterCompiler.Compile(convertv1MessageExpressions(policy.Spec.Validations), expressionOptionalVars, environment.StoredExpressions),
+		filterCompiler.CompileCondition(convertv1AuditAnnotations(policy.Spec.AuditAnnotations), optionalVars, environment.StoredExpressions),
+		filterCompiler.CompileCondition(convertv1MessageExpressions(policy.Spec.Validations), expressionOptionalVars, environment.StoredExpressions),
 		failurePolicy,
 	)
 

vendor/k8s.io/apiserver/pkg/admission/plugin/policy/validating/validator.go

@@ -41,13 +41,13 @@ import (
 // validator implements the Validator interface
 type validator struct {
 	celMatcher            matchconditions.Matcher
-	validationFilter      cel.Filter
-	auditAnnotationFilter cel.Filter
-	messageFilter         cel.Filter
+	validationFilter      cel.ConditionEvaluator
+	auditAnnotationFilter cel.ConditionEvaluator
+	messageFilter         cel.ConditionEvaluator
 	failPolicy            *v1.FailurePolicyType
 }
 
-func NewValidator(validationFilter cel.Filter, celMatcher matchconditions.Matcher, auditAnnotationFilter, messageFilter cel.Filter, failPolicy *v1.FailurePolicyType) Validator {
+func NewValidator(validationFilter cel.ConditionEvaluator, celMatcher matchconditions.Matcher, auditAnnotationFilter, messageFilter cel.ConditionEvaluator, failPolicy *v1.FailurePolicyType) Validator {
 	return &validator{
 		celMatcher:            celMatcher,
 		validationFilter:      validationFilter,
@@ -122,6 +122,7 @@ func (v *validator) Validate(ctx context.Context, matchedResource schema.GroupVe
 	messageResults, _, err := v.messageFilter.ForInput(ctx, versionedAttr, admissionRequest, expressionOptionalVars, ns, remainingBudget)
 	for i, evalResult := range evalResults {
 		var decision = &decisions[i]
+		decision.Elapsed = evalResult.Elapsed
 		// TODO: move this to generics
 		validation, ok := evalResult.ExpressionAccessor.(*ValidationCondition)
 		if !ok {
@@ -146,6 +147,7 @@ func (v *validator) Validate(ctx context.Context, matchedResource schema.GroupVe
 			decision.Message = fmt.Sprintf("failed messageExpression: %s", err)
 		} else if evalResult.EvalResult != celtypes.True {
 			decision.Action = ActionDeny
+			decision.Evaluation = EvalDeny
 			if validation.Reason == nil {
 				decision.Reason = metav1.StatusReasonInvalid
 			} else {
@@ -210,6 +212,7 @@ func (v *validator) Validate(ctx context.Context, matchedResource schema.GroupVe
 			continue
 		}
 		var auditAnnotationResult = &auditAnnotationResults[i]
+		auditAnnotationResult.Elapsed = evalResult.Elapsed
 		// TODO: move this to generics
 		validation, ok := evalResult.ExpressionAccessor.(*AuditAnnotationCondition)
 		if !ok {

vendor/k8s.io/apiserver/pkg/admission/plugin/webhook/accessors.go

@@ -50,7 +50,7 @@ type WebhookAccessor interface {
 	GetRESTClient(clientManager *webhookutil.ClientManager) (*rest.RESTClient, error)
 
 	// GetCompiledMatcher gets the compiled matcher object
-	GetCompiledMatcher(compiler cel.FilterCompiler) matchconditions.Matcher
+	GetCompiledMatcher(compiler cel.ConditionCompiler) matchconditions.Matcher
 
 	// GetName gets the webhook Name field. Note that the name is scoped to the webhook
 	// configuration and does not provide a globally unique identity, if a unique identity is
@@ -132,7 +132,7 @@ func (m *mutatingWebhookAccessor) GetType() string {
 	return "admit"
 }
 
-func (m *mutatingWebhookAccessor) GetCompiledMatcher(compiler cel.FilterCompiler) matchconditions.Matcher {
+func (m *mutatingWebhookAccessor) GetCompiledMatcher(compiler cel.ConditionCompiler) matchconditions.Matcher {
 	m.compileMatcher.Do(func() {
 		expressions := make([]cel.ExpressionAccessor, len(m.MutatingWebhook.MatchConditions))
 		for i, matchCondition := range m.MutatingWebhook.MatchConditions {
@@ -145,7 +145,7 @@ func (m *mutatingWebhookAccessor) GetCompiledMatcher(compiler cel.FilterCompiler
 		if utilfeature.DefaultFeatureGate.Enabled(features.StrictCostEnforcementForWebhooks) {
 			strictCost = true
 		}
-		m.compiledMatcher = matchconditions.NewMatcher(compiler.Compile(
+		m.compiledMatcher = matchconditions.NewMatcher(compiler.CompileCondition(
 			expressions,
 			cel.OptionalVariableDeclarations{
 				HasParams:     false,
@@ -265,7 +265,7 @@ func (v *validatingWebhookAccessor) GetRESTClient(clientManager *webhookutil.Cli
 	return v.client, v.clientErr
 }
 
-func (v *validatingWebhookAccessor) GetCompiledMatcher(compiler cel.FilterCompiler) matchconditions.Matcher {
+func (v *validatingWebhookAccessor) GetCompiledMatcher(compiler cel.ConditionCompiler) matchconditions.Matcher {
 	v.compileMatcher.Do(func() {
 		expressions := make([]cel.ExpressionAccessor, len(v.ValidatingWebhook.MatchConditions))
 		for i, matchCondition := range v.ValidatingWebhook.MatchConditions {
@@ -278,7 +278,7 @@ func (v *validatingWebhookAccessor) GetCompiledMatcher(compiler cel.FilterCompil
 		if utilfeature.DefaultFeatureGate.Enabled(features.StrictCostEnforcementForWebhooks) {
 			strictCost = true
 		}
-		v.compiledMatcher = matchconditions.NewMatcher(compiler.Compile(
+		v.compiledMatcher = matchconditions.NewMatcher(compiler.CompileCondition(
 			expressions,
 			cel.OptionalVariableDeclarations{
 				HasParams:     false,

vendor/k8s.io/apiserver/pkg/admission/plugin/webhook/generic/webhook.go

@@ -21,6 +21,9 @@ import (
 	"fmt"
 	"io"
 
+	"k8s.io/apiserver/pkg/cel/environment"
+	"k8s.io/apiserver/pkg/features"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/klog/v2"
 
 	admissionv1 "k8s.io/api/admission/v1"
@@ -38,9 +41,6 @@ import (
 	"k8s.io/apiserver/pkg/admission/plugin/webhook/predicates/object"
 	"k8s.io/apiserver/pkg/admission/plugin/webhook/predicates/rules"
 	"k8s.io/apiserver/pkg/authorization/authorizer"
-	"k8s.io/apiserver/pkg/cel/environment"
-	"k8s.io/apiserver/pkg/features"
-	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	webhookutil "k8s.io/apiserver/pkg/util/webhook"
 	"k8s.io/client-go/informers"
 	clientset "k8s.io/client-go/kubernetes"
@@ -57,7 +57,7 @@ type Webhook struct {
 	namespaceMatcher *namespace.Matcher
 	objectMatcher    *object.Matcher
 	dispatcher       Dispatcher
-	filterCompiler   cel.FilterCompiler
+	filterCompiler   cel.ConditionCompiler
 	authorizer       authorizer.Authorizer
 }
 
@@ -102,7 +102,7 @@ func NewWebhook(handler *admission.Handler, configFile io.Reader, sourceFactory
 		namespaceMatcher: &namespace.Matcher{},
 		objectMatcher:    &object.Matcher{},
 		dispatcher:       dispatcherFactory(&cm),
-		filterCompiler:   cel.NewFilterCompiler(environment.MustBaseEnvSet(environment.DefaultCompatibilityVersion(), utilfeature.DefaultFeatureGate.Enabled(features.StrictCostEnforcementForWebhooks))),
+		filterCompiler:   cel.NewConditionCompiler(environment.MustBaseEnvSet(environment.DefaultCompatibilityVersion(), utilfeature.DefaultFeatureGate.Enabled(features.StrictCostEnforcementForWebhooks))),
 	}, nil
 }
 

vendor/k8s.io/apiserver/pkg/admission/plugin/webhook/matchconditions/matcher.go

@@ -54,14 +54,14 @@ var _ Matcher = &matcher{}
 
 // matcher evaluates compiled cel expressions and determines if they match the given request or not
 type matcher struct {
-	filter      celplugin.Filter
+	filter      celplugin.ConditionEvaluator
 	failPolicy  v1.FailurePolicyType
 	matcherType string
 	matcherKind string
 	objectName  string
 }
 
-func NewMatcher(filter celplugin.Filter, failPolicy *v1.FailurePolicyType, matcherKind, matcherType, objectName string) Matcher {
+func NewMatcher(filter celplugin.ConditionEvaluator, failPolicy *v1.FailurePolicyType, matcherKind, matcherType, objectName string) Matcher {
 	var f v1.FailurePolicyType
 	if failPolicy == nil {
 		f = v1.Fail

vendor/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/dispatcher.go

@@ -190,7 +190,7 @@ func (a *mutatingDispatcher) Dispatch(ctx context.Context, attr admission.Attrib
 			admissionmetrics.Metrics.ObserveWebhook(ctx, hook.Name, time.Since(t), rejected, versionedAttr.Attributes, "admit", 200)
 		}
 		if changed {
-			// Patch had changed the object. Prepare to reinvoke all previous webhooks that are eligible for re-invocation.
+			// Patch had changed the object. Prepare to reinvoke all previous mutations that are eligible for re-invocation.
 			webhookReinvokeCtx.RequireReinvokingPreviouslyInvokedPlugins()
 			reinvokeCtx.SetShouldReinvoke()
 		}
@@ -348,7 +348,7 @@ func (a *mutatingDispatcher) callAttrMutatingHook(ctx context.Context, h *admiss
 	}
 
 	var patchedJS []byte
-	jsonSerializer := json.NewSerializer(json.DefaultMetaFactory, o.GetObjectCreater(), o.GetObjectTyper(), false)
+	jsonSerializer := json.NewSerializerWithOptions(json.DefaultMetaFactory, o.GetObjectCreater(), o.GetObjectTyper(), json.SerializerOptions{})
 	switch result.PatchType {
 	// VerifyAdmissionResponse normalizes to v1 patch types, regardless of the AdmissionReview version used
 	case admissionv1.PatchTypeJSONPatch:

vendor/k8s.io/apiserver/pkg/admission/plugin/webhook/predicates/rules/rules.go

@@ -121,7 +121,7 @@ func (r *Matcher) resource() bool {
 func IsExemptAdmissionConfigurationResource(attr admission.Attributes) bool {
 	gvk := attr.GetKind()
 	if gvk.Group == "admissionregistration.k8s.io" {
-		if gvk.Kind == "ValidatingWebhookConfiguration" || gvk.Kind == "MutatingWebhookConfiguration" || gvk.Kind == "ValidatingAdmissionPolicy" || gvk.Kind == "ValidatingAdmissionPolicyBinding" {
+		if gvk.Kind == "ValidatingWebhookConfiguration" || gvk.Kind == "MutatingWebhookConfiguration" || gvk.Kind == "ValidatingAdmissionPolicy" || gvk.Kind == "ValidatingAdmissionPolicyBinding" || gvk.Kind == "MutatingAdmissionPolicy" || gvk.Kind == "MutatingAdmissionPolicyBinding" {
 			return true
 		}
 	}