kubernetes/pkg/volume/projected/projected.go
Tero Saarni 96306f144a Set permissions on volume before publishing update
This change fixes a race condition that was caused by setting the file owner,
group and mode non-atomically, after the updated files had been published.

Users who were running non-root containers, without GID 0 permissions, and
had removed read permissions from other users by setting defaultMode: 0440 or
similar, were getting intermittent permission denied errors when accessing
files on secret or configmap volumes or service account tokens on projected
volumes during update.
2022-12-24 07:59:41 +02:00

393 lines
12 KiB
Go

/*
Copyright 2017 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 projected
import (
"fmt"
authenticationv1 "k8s.io/api/authentication/v1"
v1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/types"
utilerrors "k8s.io/apimachinery/pkg/util/errors"
"k8s.io/klog/v2"
"k8s.io/kubernetes/pkg/volume"
"k8s.io/kubernetes/pkg/volume/configmap"
"k8s.io/kubernetes/pkg/volume/downwardapi"
"k8s.io/kubernetes/pkg/volume/secret"
volumeutil "k8s.io/kubernetes/pkg/volume/util"
utilstrings "k8s.io/utils/strings"
)
// ProbeVolumePlugins is the entry point for plugin detection in a package.
func ProbeVolumePlugins() []volume.VolumePlugin {
return []volume.VolumePlugin{&projectedPlugin{}}
}
const (
projectedPluginName = "kubernetes.io/projected"
)
type projectedPlugin struct {
host volume.VolumeHost
getSecret func(namespace, name string) (*v1.Secret, error)
getConfigMap func(namespace, name string) (*v1.ConfigMap, error)
getServiceAccountToken func(namespace, name string, tr *authenticationv1.TokenRequest) (*authenticationv1.TokenRequest, error)
deleteServiceAccountToken func(podUID types.UID)
}
var _ volume.VolumePlugin = &projectedPlugin{}
func wrappedVolumeSpec() volume.Spec {
return volume.Spec{
Volume: &v1.Volume{
VolumeSource: v1.VolumeSource{
EmptyDir: &v1.EmptyDirVolumeSource{Medium: v1.StorageMediumMemory},
},
},
}
}
func getPath(uid types.UID, volName string, host volume.VolumeHost) string {
return host.GetPodVolumeDir(uid, utilstrings.EscapeQualifiedName(projectedPluginName), volName)
}
func (plugin *projectedPlugin) Init(host volume.VolumeHost) error {
plugin.host = host
plugin.getSecret = host.GetSecretFunc()
plugin.getConfigMap = host.GetConfigMapFunc()
plugin.getServiceAccountToken = host.GetServiceAccountTokenFunc()
plugin.deleteServiceAccountToken = host.DeleteServiceAccountTokenFunc()
return nil
}
func (plugin *projectedPlugin) GetPluginName() string {
return projectedPluginName
}
func (plugin *projectedPlugin) GetVolumeName(spec *volume.Spec) (string, error) {
_, _, err := getVolumeSource(spec)
if err != nil {
return "", err
}
return spec.Name(), nil
}
func (plugin *projectedPlugin) CanSupport(spec *volume.Spec) bool {
return spec.Volume != nil && spec.Volume.Projected != nil
}
func (plugin *projectedPlugin) RequiresRemount(spec *volume.Spec) bool {
return true
}
func (plugin *projectedPlugin) SupportsMountOption() bool {
return false
}
func (plugin *projectedPlugin) SupportsBulkVolumeVerification() bool {
return false
}
func (plugin *projectedPlugin) SupportsSELinuxContextMount(spec *volume.Spec) (bool, error) {
return false, nil
}
func (plugin *projectedPlugin) NewMounter(spec *volume.Spec, pod *v1.Pod, opts volume.VolumeOptions) (volume.Mounter, error) {
return &projectedVolumeMounter{
projectedVolume: &projectedVolume{
volName: spec.Name(),
sources: spec.Volume.Projected.Sources,
podUID: pod.UID,
plugin: plugin,
MetricsProvider: volume.NewCachedMetrics(volume.NewMetricsDu(getPath(pod.UID, spec.Name(), plugin.host))),
},
source: *spec.Volume.Projected,
pod: pod,
opts: &opts,
}, nil
}
func (plugin *projectedPlugin) NewUnmounter(volName string, podUID types.UID) (volume.Unmounter, error) {
return &projectedVolumeUnmounter{
&projectedVolume{
volName: volName,
podUID: podUID,
plugin: plugin,
MetricsProvider: volume.NewCachedMetrics(volume.NewMetricsDu(getPath(podUID, volName, plugin.host))),
},
}, nil
}
func (plugin *projectedPlugin) ConstructVolumeSpec(volumeName, mountPath string) (volume.ReconstructedVolume, error) {
projectedVolume := &v1.Volume{
Name: volumeName,
VolumeSource: v1.VolumeSource{
Projected: &v1.ProjectedVolumeSource{},
},
}
return volume.ReconstructedVolume{
Spec: volume.NewSpecFromVolume(projectedVolume),
}, nil
}
type projectedVolume struct {
volName string
sources []v1.VolumeProjection
podUID types.UID
plugin *projectedPlugin
volume.MetricsProvider
}
var _ volume.Volume = &projectedVolume{}
func (sv *projectedVolume) GetPath() string {
return getPath(sv.podUID, sv.volName, sv.plugin.host)
}
type projectedVolumeMounter struct {
*projectedVolume
source v1.ProjectedVolumeSource
pod *v1.Pod
opts *volume.VolumeOptions
}
var _ volume.Mounter = &projectedVolumeMounter{}
func (sv *projectedVolume) GetAttributes() volume.Attributes {
return volume.Attributes{
ReadOnly: true,
Managed: true,
SELinuxRelabel: true,
}
}
func (s *projectedVolumeMounter) SetUp(mounterArgs volume.MounterArgs) error {
return s.SetUpAt(s.GetPath(), mounterArgs)
}
func (s *projectedVolumeMounter) SetUpAt(dir string, mounterArgs volume.MounterArgs) error {
klog.V(3).Infof("Setting up volume %v for pod %v at %v", s.volName, s.pod.UID, dir)
wrapped, err := s.plugin.host.NewWrapperMounter(s.volName, wrappedVolumeSpec(), s.pod, *s.opts)
if err != nil {
return err
}
data, err := s.collectData(mounterArgs)
if err != nil {
klog.Errorf("Error preparing data for projected volume %v for pod %v/%v: %s", s.volName, s.pod.Namespace, s.pod.Name, err.Error())
return err
}
setupSuccess := false
if err := wrapped.SetUpAt(dir, mounterArgs); err != nil {
return err
}
if err := volumeutil.MakeNestedMountpoints(s.volName, dir, *s.pod); err != nil {
return err
}
defer func() {
// Clean up directories if setup fails
if !setupSuccess {
unmounter, unmountCreateErr := s.plugin.NewUnmounter(s.volName, s.podUID)
if unmountCreateErr != nil {
klog.Errorf("error cleaning up mount %s after failure. Create unmounter failed with %v", s.volName, unmountCreateErr)
return
}
tearDownErr := unmounter.TearDown()
if tearDownErr != nil {
klog.Errorf("error tearing down volume %s with : %v", s.volName, tearDownErr)
}
}
}()
writerContext := fmt.Sprintf("pod %v/%v volume %v", s.pod.Namespace, s.pod.Name, s.volName)
writer, err := volumeutil.NewAtomicWriter(dir, writerContext)
if err != nil {
klog.Errorf("Error creating atomic writer: %v", err)
return err
}
setPerms := func(_ string) error {
// This may be the first time writing and new files get created outside the timestamp subdirectory:
// change the permissions on the whole volume and not only in the timestamp directory.
return volume.SetVolumeOwnership(s, mounterArgs.FsGroup, nil /*fsGroupChangePolicy*/, volumeutil.FSGroupCompleteHook(s.plugin, nil))
}
err = writer.Write(data, setPerms)
if err != nil {
klog.Errorf("Error writing payload to dir: %v", err)
return err
}
setupSuccess = true
return nil
}
func (s *projectedVolumeMounter) collectData(mounterArgs volume.MounterArgs) (map[string]volumeutil.FileProjection, error) {
if s.source.DefaultMode == nil {
return nil, fmt.Errorf("no defaultMode used, not even the default value for it")
}
kubeClient := s.plugin.host.GetKubeClient()
if kubeClient == nil {
return nil, fmt.Errorf("cannot setup projected volume %v because kube client is not configured", s.volName)
}
errlist := []error{}
payload := make(map[string]volumeutil.FileProjection)
for _, source := range s.source.Sources {
switch {
case source.Secret != nil:
optional := source.Secret.Optional != nil && *source.Secret.Optional
secretapi, err := s.plugin.getSecret(s.pod.Namespace, source.Secret.Name)
if err != nil {
if !(errors.IsNotFound(err) && optional) {
klog.Errorf("Couldn't get secret %v/%v: %v", s.pod.Namespace, source.Secret.Name, err)
errlist = append(errlist, err)
continue
}
secretapi = &v1.Secret{
ObjectMeta: metav1.ObjectMeta{
Namespace: s.pod.Namespace,
Name: source.Secret.Name,
},
}
}
secretPayload, err := secret.MakePayload(source.Secret.Items, secretapi, s.source.DefaultMode, optional)
if err != nil {
klog.Errorf("Couldn't get secret payload %v/%v: %v", s.pod.Namespace, source.Secret.Name, err)
errlist = append(errlist, err)
continue
}
for k, v := range secretPayload {
payload[k] = v
}
case source.ConfigMap != nil:
optional := source.ConfigMap.Optional != nil && *source.ConfigMap.Optional
configMap, err := s.plugin.getConfigMap(s.pod.Namespace, source.ConfigMap.Name)
if err != nil {
if !(errors.IsNotFound(err) && optional) {
klog.Errorf("Couldn't get configMap %v/%v: %v", s.pod.Namespace, source.ConfigMap.Name, err)
errlist = append(errlist, err)
continue
}
configMap = &v1.ConfigMap{
ObjectMeta: metav1.ObjectMeta{
Namespace: s.pod.Namespace,
Name: source.ConfigMap.Name,
},
}
}
configMapPayload, err := configmap.MakePayload(source.ConfigMap.Items, configMap, s.source.DefaultMode, optional)
if err != nil {
klog.Errorf("Couldn't get configMap payload %v/%v: %v", s.pod.Namespace, source.ConfigMap.Name, err)
errlist = append(errlist, err)
continue
}
for k, v := range configMapPayload {
payload[k] = v
}
case source.DownwardAPI != nil:
downwardAPIPayload, err := downwardapi.CollectData(source.DownwardAPI.Items, s.pod, s.plugin.host, s.source.DefaultMode)
if err != nil {
errlist = append(errlist, err)
continue
}
for k, v := range downwardAPIPayload {
payload[k] = v
}
case source.ServiceAccountToken != nil:
tp := source.ServiceAccountToken
// When FsGroup is set, we depend on SetVolumeOwnership to
// change from 0600 to 0640.
mode := *s.source.DefaultMode
if mounterArgs.FsUser != nil || mounterArgs.FsGroup != nil {
mode = 0600
}
var auds []string
if len(tp.Audience) != 0 {
auds = []string{tp.Audience}
}
tr, err := s.plugin.getServiceAccountToken(s.pod.Namespace, s.pod.Spec.ServiceAccountName, &authenticationv1.TokenRequest{
Spec: authenticationv1.TokenRequestSpec{
Audiences: auds,
ExpirationSeconds: tp.ExpirationSeconds,
BoundObjectRef: &authenticationv1.BoundObjectReference{
APIVersion: "v1",
Kind: "Pod",
Name: s.pod.Name,
UID: s.pod.UID,
},
},
})
if err != nil {
errlist = append(errlist, err)
continue
}
payload[tp.Path] = volumeutil.FileProjection{
Data: []byte(tr.Status.Token),
Mode: mode,
FsUser: mounterArgs.FsUser,
}
}
}
return payload, utilerrors.NewAggregate(errlist)
}
type projectedVolumeUnmounter struct {
*projectedVolume
}
var _ volume.Unmounter = &projectedVolumeUnmounter{}
func (c *projectedVolumeUnmounter) TearDown() error {
return c.TearDownAt(c.GetPath())
}
func (c *projectedVolumeUnmounter) TearDownAt(dir string) error {
klog.V(3).Infof("Tearing down volume %v for pod %v at %v", c.volName, c.podUID, dir)
wrapped, err := c.plugin.host.NewWrapperUnmounter(c.volName, wrappedVolumeSpec(), c.podUID)
if err != nil {
return err
}
if err = wrapped.TearDownAt(dir); err != nil {
return err
}
c.plugin.deleteServiceAccountToken(c.podUID)
return nil
}
func getVolumeSource(spec *volume.Spec) (*v1.ProjectedVolumeSource, bool, error) {
if spec.Volume != nil && spec.Volume.Projected != nil {
return spec.Volume.Projected, spec.ReadOnly, nil
}
return nil, false, fmt.Errorf("Spec does not reference a projected volume type")
}