mirror of
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315 lines
9.5 KiB
Go
315 lines
9.5 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package lifecycle
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import (
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"fmt"
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"net"
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"net/http"
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"strconv"
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"k8s.io/api/core/v1"
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"k8s.io/apimachinery/pkg/types"
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"k8s.io/apimachinery/pkg/util/intstr"
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"k8s.io/klog/v2"
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kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
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kubetypes "k8s.io/kubernetes/pkg/kubelet/types"
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"k8s.io/kubernetes/pkg/kubelet/util/format"
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"k8s.io/kubernetes/pkg/security/apparmor"
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utilio "k8s.io/utils/io"
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)
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const (
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maxRespBodyLength = 10 * 1 << 10 // 10KB
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)
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type handlerRunner struct {
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httpGetter kubetypes.HTTPGetter
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commandRunner kubecontainer.CommandRunner
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containerManager podStatusProvider
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}
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type podStatusProvider interface {
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GetPodStatus(uid types.UID, name, namespace string) (*kubecontainer.PodStatus, error)
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}
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// NewHandlerRunner returns a configured lifecycle handler for a container.
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func NewHandlerRunner(httpGetter kubetypes.HTTPGetter, commandRunner kubecontainer.CommandRunner, containerManager podStatusProvider) kubecontainer.HandlerRunner {
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return &handlerRunner{
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httpGetter: httpGetter,
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commandRunner: commandRunner,
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containerManager: containerManager,
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}
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}
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func (hr *handlerRunner) Run(containerID kubecontainer.ContainerID, pod *v1.Pod, container *v1.Container, handler *v1.Handler) (string, error) {
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switch {
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case handler.Exec != nil:
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var msg string
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// TODO(tallclair): Pass a proper timeout value.
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output, err := hr.commandRunner.RunInContainer(containerID, handler.Exec.Command, 0)
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if err != nil {
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msg = fmt.Sprintf("Exec lifecycle hook (%v) for Container %q in Pod %q failed - error: %v, message: %q", handler.Exec.Command, container.Name, format.Pod(pod), err, string(output))
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klog.V(1).Infof(msg)
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}
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return msg, err
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case handler.HTTPGet != nil:
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msg, err := hr.runHTTPHandler(pod, container, handler)
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if err != nil {
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msg = fmt.Sprintf("Http lifecycle hook (%s) for Container %q in Pod %q failed - error: %v, message: %q", handler.HTTPGet.Path, container.Name, format.Pod(pod), err, msg)
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klog.V(1).Infof(msg)
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}
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return msg, err
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default:
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err := fmt.Errorf("invalid handler: %v", handler)
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msg := fmt.Sprintf("Cannot run handler: %v", err)
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klog.Errorf(msg)
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return msg, err
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}
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}
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// resolvePort attempts to turn an IntOrString port reference into a concrete port number.
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// If portReference has an int value, it is treated as a literal, and simply returns that value.
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// If portReference is a string, an attempt is first made to parse it as an integer. If that fails,
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// an attempt is made to find a port with the same name in the container spec.
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// If a port with the same name is found, it's ContainerPort value is returned. If no matching
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// port is found, an error is returned.
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func resolvePort(portReference intstr.IntOrString, container *v1.Container) (int, error) {
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if portReference.Type == intstr.Int {
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return portReference.IntValue(), nil
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}
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portName := portReference.StrVal
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port, err := strconv.Atoi(portName)
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if err == nil {
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return port, nil
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}
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for _, portSpec := range container.Ports {
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if portSpec.Name == portName {
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return int(portSpec.ContainerPort), nil
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}
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}
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return -1, fmt.Errorf("couldn't find port: %v in %v", portReference, container)
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}
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func (hr *handlerRunner) runHTTPHandler(pod *v1.Pod, container *v1.Container, handler *v1.Handler) (string, error) {
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host := handler.HTTPGet.Host
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if len(host) == 0 {
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status, err := hr.containerManager.GetPodStatus(pod.UID, pod.Name, pod.Namespace)
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if err != nil {
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klog.Errorf("Unable to get pod info, event handlers may be invalid.")
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return "", err
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}
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if len(status.IPs) == 0 {
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return "", fmt.Errorf("failed to find networking container: %v", status)
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}
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host = status.IPs[0]
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}
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var port int
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if handler.HTTPGet.Port.Type == intstr.String && len(handler.HTTPGet.Port.StrVal) == 0 {
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port = 80
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} else {
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var err error
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port, err = resolvePort(handler.HTTPGet.Port, container)
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if err != nil {
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return "", err
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}
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}
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url := fmt.Sprintf("http://%s/%s", net.JoinHostPort(host, strconv.Itoa(port)), handler.HTTPGet.Path)
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resp, err := hr.httpGetter.Get(url)
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return getHTTPRespBody(resp), err
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}
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func getHTTPRespBody(resp *http.Response) string {
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if resp == nil {
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return ""
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}
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defer resp.Body.Close()
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bytes, err := utilio.ReadAtMost(resp.Body, maxRespBodyLength)
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if err == nil || err == utilio.ErrLimitReached {
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return string(bytes)
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}
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return ""
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}
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// NewAppArmorAdmitHandler returns a PodAdmitHandler which is used to evaluate
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// if a pod can be admitted from the perspective of AppArmor.
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func NewAppArmorAdmitHandler(validator apparmor.Validator) PodAdmitHandler {
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return &appArmorAdmitHandler{
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Validator: validator,
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}
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}
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type appArmorAdmitHandler struct {
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apparmor.Validator
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}
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func (a *appArmorAdmitHandler) Admit(attrs *PodAdmitAttributes) PodAdmitResult {
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// If the pod is already running or terminated, no need to recheck AppArmor.
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if attrs.Pod.Status.Phase != v1.PodPending {
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return PodAdmitResult{Admit: true}
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}
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err := a.Validate(attrs.Pod)
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if err == nil {
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return PodAdmitResult{Admit: true}
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}
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return PodAdmitResult{
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Admit: false,
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Reason: "AppArmor",
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Message: fmt.Sprintf("Cannot enforce AppArmor: %v", err),
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}
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}
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// NewNoNewPrivsAdmitHandler returns a PodAdmitHandler which is used to evaluate
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// if a pod can be admitted from the perspective of NoNewPrivs.
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func NewNoNewPrivsAdmitHandler(runtime kubecontainer.Runtime) PodAdmitHandler {
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return &noNewPrivsAdmitHandler{
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Runtime: runtime,
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}
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}
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type noNewPrivsAdmitHandler struct {
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kubecontainer.Runtime
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}
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func (a *noNewPrivsAdmitHandler) Admit(attrs *PodAdmitAttributes) PodAdmitResult {
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// If the pod is already running or terminated, no need to recheck NoNewPrivs.
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if attrs.Pod.Status.Phase != v1.PodPending {
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return PodAdmitResult{Admit: true}
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}
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// If the containers in a pod do not require no-new-privs, admit it.
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if !noNewPrivsRequired(attrs.Pod) {
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return PodAdmitResult{Admit: true}
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}
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// Always admit runtimes except docker.
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if a.Runtime.Type() != kubetypes.DockerContainerRuntime {
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return PodAdmitResult{Admit: true}
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}
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// Make sure docker api version is valid.
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rversion, err := a.Runtime.APIVersion()
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if err != nil {
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return PodAdmitResult{
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Admit: false,
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Reason: "NoNewPrivs",
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Message: fmt.Sprintf("Cannot enforce NoNewPrivs: %v", err),
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}
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}
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v, err := rversion.Compare("1.23.0")
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if err != nil {
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return PodAdmitResult{
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Admit: false,
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Reason: "NoNewPrivs",
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Message: fmt.Sprintf("Cannot enforce NoNewPrivs: %v", err),
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}
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}
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// If the version is less than 1.23 it will return -1 above.
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if v == -1 {
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return PodAdmitResult{
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Admit: false,
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Reason: "NoNewPrivs",
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Message: fmt.Sprintf("Cannot enforce NoNewPrivs: docker runtime API version %q must be greater than or equal to 1.23", rversion.String()),
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}
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}
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return PodAdmitResult{Admit: true}
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}
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func noNewPrivsRequired(pod *v1.Pod) bool {
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// Iterate over pod containers and check if we added no-new-privs.
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for _, c := range pod.Spec.Containers {
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if c.SecurityContext != nil && c.SecurityContext.AllowPrivilegeEscalation != nil && !*c.SecurityContext.AllowPrivilegeEscalation {
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return true
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}
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}
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return false
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}
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// NewProcMountAdmitHandler returns a PodAdmitHandler which is used to evaluate
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// if a pod can be admitted from the perspective of ProcMount.
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func NewProcMountAdmitHandler(runtime kubecontainer.Runtime) PodAdmitHandler {
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return &procMountAdmitHandler{
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Runtime: runtime,
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}
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}
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type procMountAdmitHandler struct {
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kubecontainer.Runtime
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}
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func (a *procMountAdmitHandler) Admit(attrs *PodAdmitAttributes) PodAdmitResult {
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// If the pod is already running or terminated, no need to recheck NoNewPrivs.
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if attrs.Pod.Status.Phase != v1.PodPending {
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return PodAdmitResult{Admit: true}
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}
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// If the containers in a pod only need the default ProcMountType, admit it.
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if procMountIsDefault(attrs.Pod) {
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return PodAdmitResult{Admit: true}
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}
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// Always admit runtimes except docker.
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if a.Runtime.Type() != kubetypes.DockerContainerRuntime {
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return PodAdmitResult{Admit: true}
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}
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// Make sure docker api version is valid.
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// Merged in https://github.com/moby/moby/pull/36644
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rversion, err := a.Runtime.APIVersion()
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if err != nil {
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return PodAdmitResult{
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Admit: false,
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Reason: "ProcMount",
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Message: fmt.Sprintf("Cannot enforce ProcMount: %v", err),
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}
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}
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v, err := rversion.Compare("1.38.0")
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if err != nil {
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return PodAdmitResult{
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Admit: false,
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Reason: "ProcMount",
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Message: fmt.Sprintf("Cannot enforce ProcMount: %v", err),
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}
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}
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// If the version is less than 1.38 it will return -1 above.
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if v == -1 {
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return PodAdmitResult{
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Admit: false,
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Reason: "ProcMount",
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Message: fmt.Sprintf("Cannot enforce ProcMount: docker runtime API version %q must be greater than or equal to 1.38", rversion.String()),
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}
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}
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return PodAdmitResult{Admit: true}
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}
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func procMountIsDefault(pod *v1.Pod) bool {
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// Iterate over pod containers and check if we are using the DefaultProcMountType
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// for all containers.
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for _, c := range pod.Spec.Containers {
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if c.SecurityContext != nil {
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if c.SecurityContext.ProcMount != nil && *c.SecurityContext.ProcMount != v1.DefaultProcMount {
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return false
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}
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}
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}
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return true
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}
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