253 lines
7.3 KiB
Go
253 lines
7.3 KiB
Go
/*
|
|
Copyright 2021 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 podsecurity
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
"sync"
|
|
|
|
// install conversions for types we need to convert
|
|
_ "k8s.io/kubernetes/pkg/apis/apps/install"
|
|
_ "k8s.io/kubernetes/pkg/apis/batch/install"
|
|
_ "k8s.io/kubernetes/pkg/apis/core/install"
|
|
|
|
appsv1 "k8s.io/api/apps/v1"
|
|
batchv1 "k8s.io/api/batch/v1"
|
|
corev1 "k8s.io/api/core/v1"
|
|
"k8s.io/apimachinery/pkg/runtime"
|
|
"k8s.io/apimachinery/pkg/runtime/schema"
|
|
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
|
|
"k8s.io/apiserver/pkg/admission"
|
|
genericadmissioninit "k8s.io/apiserver/pkg/admission/initializer"
|
|
"k8s.io/apiserver/pkg/audit"
|
|
"k8s.io/apiserver/pkg/warning"
|
|
"k8s.io/client-go/informers"
|
|
"k8s.io/client-go/kubernetes"
|
|
corev1listers "k8s.io/client-go/listers/core/v1"
|
|
"k8s.io/component-base/featuregate"
|
|
"k8s.io/kubernetes/pkg/api/legacyscheme"
|
|
"k8s.io/kubernetes/pkg/apis/apps"
|
|
"k8s.io/kubernetes/pkg/apis/batch"
|
|
"k8s.io/kubernetes/pkg/apis/core"
|
|
"k8s.io/kubernetes/pkg/features"
|
|
podsecurityadmission "k8s.io/pod-security-admission/admission"
|
|
podsecurityconfigloader "k8s.io/pod-security-admission/admission/api/load"
|
|
podsecurityadmissionapi "k8s.io/pod-security-admission/api"
|
|
"k8s.io/pod-security-admission/policy"
|
|
)
|
|
|
|
// PluginName is a string with the name of the plugin
|
|
const PluginName = "PodSecurity"
|
|
|
|
// Register registers a plugin
|
|
func Register(plugins *admission.Plugins) {
|
|
plugins.Register(PluginName, func(reader io.Reader) (admission.Interface, error) {
|
|
return newPlugin(reader)
|
|
})
|
|
}
|
|
|
|
// Plugin holds state for and implements the admission plugin.
|
|
type Plugin struct {
|
|
*admission.Handler
|
|
|
|
enabled bool
|
|
inspectedFeatureGates bool
|
|
|
|
client kubernetes.Interface
|
|
namespaceLister corev1listers.NamespaceLister
|
|
podLister corev1listers.PodLister
|
|
|
|
delegate *podsecurityadmission.Admission
|
|
}
|
|
|
|
var _ admission.ValidationInterface = &Plugin{}
|
|
var _ genericadmissioninit.WantsExternalKubeInformerFactory = &Plugin{}
|
|
var _ genericadmissioninit.WantsExternalKubeClientSet = &Plugin{}
|
|
|
|
// newPlugin creates a new admission plugin.
|
|
func newPlugin(reader io.Reader) (*Plugin, error) {
|
|
config, err := podsecurityconfigloader.LoadFromReader(reader)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
evaluator, err := policy.NewEvaluator(policy.DefaultChecks())
|
|
if err != nil {
|
|
return nil, fmt.Errorf("could not create PodSecurityRegistry: %w", err)
|
|
}
|
|
|
|
return &Plugin{
|
|
Handler: admission.NewHandler(admission.Create, admission.Update),
|
|
delegate: &podsecurityadmission.Admission{
|
|
Configuration: config,
|
|
Evaluator: evaluator,
|
|
Metrics: nil, // TODO: wire to default prometheus metrics
|
|
PodSpecExtractor: podsecurityadmission.DefaultPodSpecExtractor{},
|
|
},
|
|
}, nil
|
|
}
|
|
|
|
// SetExternalKubeInformerFactory registers an informer
|
|
func (p *Plugin) SetExternalKubeInformerFactory(f informers.SharedInformerFactory) {
|
|
namespaceInformer := f.Core().V1().Namespaces()
|
|
p.namespaceLister = namespaceInformer.Lister()
|
|
p.podLister = f.Core().V1().Pods().Lister()
|
|
p.SetReadyFunc(namespaceInformer.Informer().HasSynced)
|
|
p.updateDelegate()
|
|
}
|
|
|
|
// SetExternalKubeClientSet sets the plugin's client
|
|
func (p *Plugin) SetExternalKubeClientSet(client kubernetes.Interface) {
|
|
p.client = client
|
|
p.updateDelegate()
|
|
}
|
|
|
|
func (p *Plugin) updateDelegate() {
|
|
// return early if we don't have what we need to set up the admission delegate
|
|
if p.namespaceLister == nil {
|
|
return
|
|
}
|
|
if p.podLister == nil {
|
|
return
|
|
}
|
|
if p.client == nil {
|
|
return
|
|
}
|
|
p.delegate.PodLister = podsecurityadmission.PodListerFromInformer(p.podLister)
|
|
p.delegate.NamespaceGetter = podsecurityadmission.NamespaceGetterFromListerAndClient(p.namespaceLister, p.client)
|
|
}
|
|
|
|
func (c *Plugin) InspectFeatureGates(featureGates featuregate.FeatureGate) {
|
|
c.enabled = featureGates.Enabled(features.PodSecurity)
|
|
c.inspectedFeatureGates = true
|
|
}
|
|
|
|
// ValidateInitialization ensures all required options are set
|
|
func (p *Plugin) ValidateInitialization() error {
|
|
if !p.inspectedFeatureGates {
|
|
return fmt.Errorf("%s did not see feature gates", PluginName)
|
|
}
|
|
if err := p.delegate.CompleteConfiguration(); err != nil {
|
|
return fmt.Errorf("%s configuration error: %w", PluginName, err)
|
|
}
|
|
if err := p.delegate.ValidateConfiguration(); err != nil {
|
|
return fmt.Errorf("%s invalid: %w", PluginName, err)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
var (
|
|
applicableResources = map[schema.GroupResource]bool{
|
|
corev1.Resource("pods"): true,
|
|
corev1.Resource("namespaces"): true,
|
|
}
|
|
)
|
|
|
|
func (p *Plugin) Validate(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces) error {
|
|
if !p.enabled {
|
|
return nil
|
|
}
|
|
gr := a.GetResource().GroupResource()
|
|
if !applicableResources[gr] && !p.delegate.PodSpecExtractor.HasPodSpec(gr) {
|
|
return nil
|
|
}
|
|
|
|
a = &lazyConvertingAttributes{Attributes: a}
|
|
|
|
result := p.delegate.Validate(ctx, a)
|
|
for _, w := range result.Warnings {
|
|
warning.AddWarning(ctx, "", w)
|
|
}
|
|
for k, v := range result.AuditAnnotations {
|
|
audit.AddAuditAnnotation(ctx, podsecurityadmissionapi.AuditAnnotationPrefix+k, v)
|
|
}
|
|
if !result.Allowed {
|
|
if result.Result != nil && len(result.Result.Message) > 0 {
|
|
// TODO: use code/reason/etc from status
|
|
return admission.NewForbidden(a, errors.New(result.Result.Message))
|
|
}
|
|
return admission.NewForbidden(a, errors.New("Not allowed by PodSecurity"))
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type lazyConvertingAttributes struct {
|
|
admission.Attributes
|
|
|
|
convertObjectOnce sync.Once
|
|
convertedObject runtime.Object
|
|
|
|
convertOldObjectOnce sync.Once
|
|
convertedOldObject runtime.Object
|
|
}
|
|
|
|
func (l *lazyConvertingAttributes) GetObject() runtime.Object {
|
|
l.convertObjectOnce.Do(func() {
|
|
obj, err := convert(l.Attributes.GetObject())
|
|
if err != nil {
|
|
utilruntime.HandleError(err)
|
|
}
|
|
l.convertedObject = obj
|
|
})
|
|
return l.convertedObject
|
|
}
|
|
func (l *lazyConvertingAttributes) GetOldObject() runtime.Object {
|
|
l.convertOldObjectOnce.Do(func() {
|
|
obj, err := convert(l.Attributes.GetOldObject())
|
|
if err != nil {
|
|
utilruntime.HandleError(err)
|
|
}
|
|
l.convertedOldObject = obj
|
|
})
|
|
return l.convertedOldObject
|
|
}
|
|
|
|
func convert(in runtime.Object) (runtime.Object, error) {
|
|
var out runtime.Object
|
|
switch in.(type) {
|
|
case *core.Namespace:
|
|
out = &corev1.Namespace{}
|
|
case *core.Pod:
|
|
out = &corev1.Pod{}
|
|
case *core.ReplicationController:
|
|
out = &corev1.ReplicationController{}
|
|
case *core.PodTemplate:
|
|
out = &corev1.PodTemplate{}
|
|
case *apps.ReplicaSet:
|
|
out = &appsv1.ReplicaSet{}
|
|
case *apps.Deployment:
|
|
out = &appsv1.Deployment{}
|
|
case *apps.StatefulSet:
|
|
out = &appsv1.StatefulSet{}
|
|
case *apps.DaemonSet:
|
|
out = &appsv1.DaemonSet{}
|
|
case *batch.Job:
|
|
out = &batchv1.Job{}
|
|
case *batch.CronJob:
|
|
out = &batchv1.CronJob{}
|
|
default:
|
|
return in, fmt.Errorf("unexpected type %T", in)
|
|
}
|
|
if err := legacyscheme.Scheme.Convert(in, out, nil); err != nil {
|
|
return in, err
|
|
}
|
|
return out, nil
|
|
}
|