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Code Issues Projects Releases Wiki Activity

Remove deprecated DenyEscalatingExec / DenyExecOnPrivileged admission

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This commit is contained in:
Jordan Liggitt 2021-02-01 12:18:05 -05:00
parent b418bc83db
commit 3579f88e4d
6 changed files with 0 additions and 425 deletions
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1
pkg/kubeapiserver/options/BUILD
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@ -29,7 +29,6 @@ go_library(
"//plugin/pkg/admission/defaulttolerationseconds:go_default_library", "//plugin/pkg/admission/defaulttolerationseconds:go_default_library",
"//plugin/pkg/admission/deny:go_default_library", "//plugin/pkg/admission/deny:go_default_library",
"//plugin/pkg/admission/eventratelimit:go_default_library", "//plugin/pkg/admission/eventratelimit:go_default_library",
"//plugin/pkg/admission/exec:go_default_library",
"//plugin/pkg/admission/extendedresourcetoleration:go_default_library", "//plugin/pkg/admission/extendedresourcetoleration:go_default_library",
"//plugin/pkg/admission/gc:go_default_library", "//plugin/pkg/admission/gc:go_default_library",
"//plugin/pkg/admission/imagepolicy:go_default_library", "//plugin/pkg/admission/imagepolicy:go_default_library",

4
pkg/kubeapiserver/options/plugins.go
View File

@ -31,7 +31,6 @@ import (
"k8s.io/kubernetes/plugin/pkg/admission/defaulttolerationseconds" "k8s.io/kubernetes/plugin/pkg/admission/defaulttolerationseconds"
"k8s.io/kubernetes/plugin/pkg/admission/deny" "k8s.io/kubernetes/plugin/pkg/admission/deny"
"k8s.io/kubernetes/plugin/pkg/admission/eventratelimit" "k8s.io/kubernetes/plugin/pkg/admission/eventratelimit"
"k8s.io/kubernetes/plugin/pkg/admission/exec"
"k8s.io/kubernetes/plugin/pkg/admission/extendedresourcetoleration" "k8s.io/kubernetes/plugin/pkg/admission/extendedresourcetoleration"
"k8s.io/kubernetes/plugin/pkg/admission/gc" "k8s.io/kubernetes/plugin/pkg/admission/gc"
"k8s.io/kubernetes/plugin/pkg/admission/imagepolicy" "k8s.io/kubernetes/plugin/pkg/admission/imagepolicy"
@ -79,8 +78,6 @@ var AllOrderedPlugins = []string{
podpriority.PluginName, // Priority podpriority.PluginName, // Priority
defaulttolerationseconds.PluginName, // DefaultTolerationSeconds defaulttolerationseconds.PluginName, // DefaultTolerationSeconds
podtolerationrestriction.PluginName, // PodTolerationRestriction podtolerationrestriction.PluginName, // PodTolerationRestriction
exec.DenyEscalatingExec, // DenyEscalatingExec
exec.DenyExecOnPrivileged, // DenyExecOnPrivileged
eventratelimit.PluginName, // EventRateLimit eventratelimit.PluginName, // EventRateLimit
extendedresourcetoleration.PluginName, // ExtendedResourceToleration extendedresourcetoleration.PluginName, // ExtendedResourceToleration
label.PluginName, // PersistentVolumeLabel label.PluginName, // PersistentVolumeLabel
@ -113,7 +110,6 @@ func RegisterAllAdmissionPlugins(plugins *admission.Plugins) {
defaultingressclass.Register(plugins) defaultingressclass.Register(plugins)
deny.Register(plugins) // DEPRECATED as no real meaning deny.Register(plugins) // DEPRECATED as no real meaning
eventratelimit.Register(plugins) eventratelimit.Register(plugins)
exec.Register(plugins)
extendedresourcetoleration.Register(plugins) extendedresourcetoleration.Register(plugins)
gc.Register(plugins) gc.Register(plugins)
imagepolicy.Register(plugins) imagepolicy.Register(plugins)

1
plugin/BUILD
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@ -19,7 +19,6 @@ filegroup(
"//plugin/pkg/admission/defaulttolerationseconds:all-srcs", "//plugin/pkg/admission/defaulttolerationseconds:all-srcs",
"//plugin/pkg/admission/deny:all-srcs", "//plugin/pkg/admission/deny:all-srcs",
"//plugin/pkg/admission/eventratelimit:all-srcs", "//plugin/pkg/admission/eventratelimit:all-srcs",
"//plugin/pkg/admission/exec:all-srcs",
"//plugin/pkg/admission/extendedresourcetoleration:all-srcs", "//plugin/pkg/admission/extendedresourcetoleration:all-srcs",
"//plugin/pkg/admission/gc:all-srcs", "//plugin/pkg/admission/gc:all-srcs",
"//plugin/pkg/admission/imagepolicy:all-srcs", "//plugin/pkg/admission/imagepolicy:all-srcs",

50
plugin/pkg/admission/exec/BUILD
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@ -1,50 +0,0 @@
package(default_visibility = ["//visibility:public"])
load(
"@io_bazel_rules_go//go:def.bzl",
"go_library",
"go_test",
)
go_library(
name = "go_default_library",
srcs = ["admission.go"],
importpath = "k8s.io/kubernetes/plugin/pkg/admission/exec",
deps = [
"//pkg/api/v1/pod:go_default_library",
"//staging/src/k8s.io/api/core/v1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
"//staging/src/k8s.io/apiserver/pkg/admission:go_default_library",
"//staging/src/k8s.io/apiserver/pkg/admission/initializer:go_default_library",
"//staging/src/k8s.io/client-go/kubernetes:go_default_library",
"//vendor/k8s.io/klog/v2:go_default_library",
],
)
go_test(
name = "go_default_test",
srcs = ["admission_test.go"],
embed = [":go_default_library"],
deps = [
"//pkg/apis/core:go_default_library",
"//staging/src/k8s.io/api/core/v1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
"//staging/src/k8s.io/apiserver/pkg/admission:go_default_library",
"//staging/src/k8s.io/client-go/kubernetes/fake:go_default_library",
"//staging/src/k8s.io/client-go/testing:go_default_library",
],
)
filegroup(
name = "package-srcs",
srcs = glob(["**"]),
tags = ["automanaged"],
visibility = ["//visibility:private"],
)
filegroup(
name = "all-srcs",
srcs = [":package-srcs"],
tags = ["automanaged"],
)

163
plugin/pkg/admission/exec/admission.go
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@ -1,163 +0,0 @@
/*
Copyright 2015 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 exec
import (
"context"
"fmt"
"io"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apiserver/pkg/admission"
genericadmissioninitializer "k8s.io/apiserver/pkg/admission/initializer"
"k8s.io/client-go/kubernetes"
"k8s.io/klog/v2"
podutil "k8s.io/kubernetes/pkg/api/v1/pod"
)
const (
// DenyEscalatingExec indicates name of admission plugin.
// Deprecated, will be removed in v1.18.
// Use of PodSecurityPolicy or a custom admission plugin to limit creation of pods is recommended instead.
DenyEscalatingExec = "DenyEscalatingExec"
// DenyExecOnPrivileged indicates name of admission plugin.
// Deprecated, will be removed in v1.18.
// Use of PodSecurityPolicy or a custom admission plugin to limit creation of pods is recommended instead.
DenyExecOnPrivileged = "DenyExecOnPrivileged"
)
// Register registers a plugin
func Register(plugins *admission.Plugins) {
plugins.Register(DenyEscalatingExec, func(config io.Reader) (admission.Interface, error) {
klog.Warningf("the %s admission plugin is deprecated and will be removed in v1.18", DenyEscalatingExec)
klog.Warningf("use of PodSecurityPolicy or a custom admission plugin to limit creation of pods is recommended instead")
return NewDenyEscalatingExec(), nil
})
// This is for legacy support of the DenyExecOnPrivileged admission controller. Most
// of the time DenyEscalatingExec should be preferred.
plugins.Register(DenyExecOnPrivileged, func(config io.Reader) (admission.Interface, error) {
klog.Warningf("the %s admission plugin is deprecated and will be removed in v1.18", DenyExecOnPrivileged)
klog.Warningf("use of PodSecurityPolicy or a custom admission plugin to limit creation of pods is recommended instead")
return NewDenyExecOnPrivileged(), nil
})
}
// DenyExec is an implementation of admission.Interface which says no to a pod/exec on
// a pod using host based configurations.
type DenyExec struct {
*admission.Handler
client kubernetes.Interface
// these flags control which items will be checked to deny exec/attach
hostNetwork bool
hostIPC bool
hostPID bool
privileged bool
}
var _ admission.ValidationInterface = &DenyExec{}
var _ = genericadmissioninitializer.WantsExternalKubeClientSet(&DenyExec{})
// NewDenyExecOnPrivileged creates a new admission controller that is only checking the privileged
// option. This is for legacy support of the DenyExecOnPrivileged admission controller.
// Most of the time NewDenyEscalatingExec should be preferred.
func NewDenyExecOnPrivileged() *DenyExec {
return &DenyExec{
Handler: admission.NewHandler(admission.Connect),
hostNetwork: false,
hostIPC: false,
hostPID: false,
privileged: true,
}
}
// NewDenyEscalatingExec creates a new admission controller that denies an exec operation on a pod
// using host based configurations.
func NewDenyEscalatingExec() *DenyExec {
return &DenyExec{
Handler: admission.NewHandler(admission.Connect),
hostNetwork: true,
hostIPC: true,
hostPID: true,
privileged: true,
}
}
// SetExternalKubeClientSet implements the WantsInternalKubeClientSet interface.
func (d *DenyExec) SetExternalKubeClientSet(client kubernetes.Interface) {
d.client = client
}
// ValidateInitialization implements the InitializationValidator interface.
func (d *DenyExec) ValidateInitialization() error {
if d.client == nil {
return fmt.Errorf("missing client")
}
return nil
}
// Validate makes an admission decision based on the request attributes
func (d *DenyExec) Validate(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces) (err error) {
path := a.GetResource().Resource
if subresource := a.GetSubresource(); subresource != "" {
path = path + "/" + subresource
}
// Only handle exec or attach requests on pods
if path != "pods/exec" && path != "pods/attach" {
return nil
}
pod, err := d.client.CoreV1().Pods(a.GetNamespace()).Get(context.TODO(), a.GetName(), metav1.GetOptions{})
if err != nil {
return admission.NewForbidden(a, err)
}
if d.hostNetwork && pod.Spec.HostNetwork {
return admission.NewForbidden(a, fmt.Errorf("cannot exec into or attach to a container using host network"))
}
if d.hostPID && pod.Spec.HostPID {
return admission.NewForbidden(a, fmt.Errorf("cannot exec into or attach to a container using host pid"))
}
if d.hostIPC && pod.Spec.HostIPC {
return admission.NewForbidden(a, fmt.Errorf("cannot exec into or attach to a container using host ipc"))
}
if d.privileged && isPrivileged(pod) {
return admission.NewForbidden(a, fmt.Errorf("cannot exec into or attach to a privileged container"))
}
return nil
}
// isPrivileged will return true a pod has any privileged containers
func isPrivileged(pod *corev1.Pod) bool {
var privileged bool
podutil.VisitContainers(&pod.Spec, podutil.AllContainers, func(c *corev1.Container, containerType podutil.ContainerType) bool {
if c.SecurityContext == nil || c.SecurityContext.Privileged == nil {
return true
}
if *c.SecurityContext.Privileged {
privileged = true
return false
}
return true
})
return privileged
}

206
plugin/pkg/admission/exec/admission_test.go
View File

@ -1,206 +0,0 @@
/*
Copyright 2015 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 exec
import (
"context"
"testing"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apiserver/pkg/admission"
"k8s.io/client-go/kubernetes/fake"
core "k8s.io/client-go/testing"
api "k8s.io/kubernetes/pkg/apis/core"
)
// newAllowEscalatingExec returns `admission.Interface` that allows execution on
// "hostIPC", "hostPID" and "privileged".
func newAllowEscalatingExec() *DenyExec {
return &DenyExec{
Handler: admission.NewHandler(admission.Connect),
hostIPC: false,
hostPID: false,
privileged: false,
}
}
func TestAdmission(t *testing.T) {
privPod := validPod("privileged")
priv := true
privPod.Spec.Containers[0].SecurityContext = &corev1.SecurityContext{
Privileged: &priv,
}
hostPIDPod := validPod("hostPID")
hostPIDPod.Spec.HostPID = true
hostIPCPod := validPod("hostIPC")
hostIPCPod.Spec.HostIPC = true
testCases := map[string]struct {
pod *corev1.Pod
shouldAccept bool
}{
"priv": {
shouldAccept: false,
pod: privPod,
},
"hostPID": {
shouldAccept: false,
pod: hostPIDPod,
},
"hostIPC": {
shouldAccept: false,
pod: hostIPCPod,
},
"non privileged": {
shouldAccept: true,
pod: validPod("nonPrivileged"),
},
}
// Get the direct object though to allow testAdmission to inject the client
handler := NewDenyEscalatingExec()
for _, tc := range testCases {
testAdmission(t, tc.pod, handler, tc.shouldAccept)
}
// run with a permissive config and all cases should pass
handler = newAllowEscalatingExec()
for _, tc := range testCases {
testAdmission(t, tc.pod, handler, true)
}
// run against an init container
handler = NewDenyEscalatingExec()
for _, tc := range testCases {
tc.pod.Spec.InitContainers = tc.pod.Spec.Containers
tc.pod.Spec.Containers = nil
testAdmission(t, tc.pod, handler, tc.shouldAccept)
}
// run with a permissive config and all cases should pass
handler = newAllowEscalatingExec()
for _, tc := range testCases {
testAdmission(t, tc.pod, handler, true)
}
}
func testAdmission(t *testing.T, pod *corev1.Pod, handler *DenyExec, shouldAccept bool) {
mockClient := &fake.Clientset{}
mockClient.AddReactor("get", "pods", func(action core.Action) (bool, runtime.Object, error) {
if action.(core.GetAction).GetName() == pod.Name {
return true, pod, nil
}
t.Errorf("Unexpected API call: %#v", action)
return true, nil, nil
})
handler.SetExternalKubeClientSet(mockClient)
admission.ValidateInitialization(handler)
// pods/exec
{
err := handler.Validate(context.TODO(), admission.NewAttributesRecord(nil, nil, api.Kind("Pod").WithVersion("version"), "test", pod.Name, api.Resource("pods").WithVersion("version"), "exec", admission.Connect, nil, false, nil), nil)
if shouldAccept && err != nil {
t.Errorf("Unexpected error returned from admission handler: %v", err)
}
if !shouldAccept && err == nil {
t.Errorf("An error was expected from the admission handler. Received nil")
}
}
// pods/attach
{
err := handler.Validate(context.TODO(), admission.NewAttributesRecord(nil, nil, api.Kind("Pod").WithVersion("version"), "test", pod.Name, api.Resource("pods").WithVersion("version"), "attach", admission.Connect, nil, false, nil), nil)
if shouldAccept && err != nil {
t.Errorf("Unexpected error returned from admission handler: %v", err)
}
if !shouldAccept && err == nil {
t.Errorf("An error was expected from the admission handler. Received nil")
}
}
}
// Test to ensure legacy admission controller works as expected.
func TestDenyExecOnPrivileged(t *testing.T) {
privPod := validPod("privileged")
priv := true
privPod.Spec.Containers[0].SecurityContext = &corev1.SecurityContext{
Privileged: &priv,
}
hostPIDPod := validPod("hostPID")
hostPIDPod.Spec.HostPID = true
hostIPCPod := validPod("hostIPC")
hostIPCPod.Spec.HostIPC = true
testCases := map[string]struct {
pod *corev1.Pod
shouldAccept bool
}{
"priv": {
shouldAccept: false,
pod: privPod,
},
"hostPID": {
shouldAccept: true,
pod: hostPIDPod,
},
"hostIPC": {
shouldAccept: true,
pod: hostIPCPod,
},
"non privileged": {
shouldAccept: true,
pod: validPod("nonPrivileged"),
},
}
// Get the direct object though to allow testAdmission to inject the client
handler := NewDenyExecOnPrivileged()
for _, tc := range testCases {
testAdmission(t, tc.pod, handler, tc.shouldAccept)
}
// test init containers
for _, tc := range testCases {
tc.pod.Spec.InitContainers = tc.pod.Spec.Containers
tc.pod.Spec.Containers = nil
testAdmission(t, tc.pod, handler, tc.shouldAccept)
}
}
func validPod(name string) *corev1.Pod {
return &corev1.Pod{
ObjectMeta: metav1.ObjectMeta{Name: name, Namespace: "test"},
Spec: corev1.PodSpec{
Containers: []corev1.Container{
{Name: "ctr1", Image: "image"},
{Name: "ctr2", Image: "image2"},
},
},
}
}