/
token.go
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/
token.go
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/*
Copyright 2018 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 storage
import (
"context"
"fmt"
"time"
authenticationapiv1 "k8s.io/api/authentication/v1"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/types"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/apimachinery/pkg/util/validation/field"
"k8s.io/apiserver/pkg/authentication/authenticator"
genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
"k8s.io/apiserver/pkg/registry/rest"
"k8s.io/apiserver/pkg/warning"
authenticationapi "k8s.io/kubernetes/pkg/apis/authentication"
authenticationvalidation "k8s.io/kubernetes/pkg/apis/authentication/validation"
api "k8s.io/kubernetes/pkg/apis/core"
token "k8s.io/kubernetes/pkg/serviceaccount"
)
func (r *TokenREST) New() runtime.Object {
return &authenticationapi.TokenRequest{}
}
// Destroy cleans up resources on shutdown.
func (r *TokenREST) Destroy() {
// Given no underlying store, we don't destroy anything
// here explicitly.
}
type TokenREST struct {
svcaccts getter
pods getter
secrets getter
issuer token.TokenGenerator
auds authenticator.Audiences
audsSet sets.String
maxExpirationSeconds int64
extendExpiration bool
}
var _ = rest.NamedCreater(&TokenREST{})
var _ = rest.GroupVersionKindProvider(&TokenREST{})
var gvk = schema.GroupVersionKind{
Group: authenticationapiv1.SchemeGroupVersion.Group,
Version: authenticationapiv1.SchemeGroupVersion.Version,
Kind: "TokenRequest",
}
func (r *TokenREST) Create(ctx context.Context, name string, obj runtime.Object, createValidation rest.ValidateObjectFunc, options *metav1.CreateOptions) (runtime.Object, error) {
req := obj.(*authenticationapi.TokenRequest)
// Get the namespace from the context (populated from the URL).
namespace, ok := genericapirequest.NamespaceFrom(ctx)
if !ok {
return nil, errors.NewBadRequest("namespace is required")
}
// require name/namespace in the body to match URL if specified
if len(req.Name) > 0 && req.Name != name {
errs := field.ErrorList{field.Invalid(field.NewPath("metadata").Child("name"), req.Name, "must match the service account name if specified")}
return nil, errors.NewInvalid(gvk.GroupKind(), name, errs)
}
if len(req.Namespace) > 0 && req.Namespace != namespace {
errs := field.ErrorList{field.Invalid(field.NewPath("metadata").Child("namespace"), req.Namespace, "must match the service account namespace if specified")}
return nil, errors.NewInvalid(gvk.GroupKind(), name, errs)
}
// Lookup service account
svcacctObj, err := r.svcaccts.Get(ctx, name, &metav1.GetOptions{})
if err != nil {
return nil, err
}
svcacct := svcacctObj.(*api.ServiceAccount)
// Default unset spec audiences to API server audiences based on server config
if len(req.Spec.Audiences) == 0 {
req.Spec.Audiences = r.auds
}
// Populate metadata fields if not set
if len(req.Name) == 0 {
req.Name = svcacct.Name
}
if len(req.Namespace) == 0 {
req.Namespace = svcacct.Namespace
}
// Save current time before building the token, to make sure the expiration
// returned in TokenRequestStatus would be <= the exp field in token.
nowTime := time.Now()
req.CreationTimestamp = metav1.NewTime(nowTime)
// Clear status
req.Status = authenticationapi.TokenRequestStatus{}
// call static validation, then validating admission
if errs := authenticationvalidation.ValidateTokenRequest(req); len(errs) != 0 {
return nil, errors.NewInvalid(gvk.GroupKind(), "", errs)
}
if createValidation != nil {
if err := createValidation(ctx, obj.DeepCopyObject()); err != nil {
return nil, err
}
}
var (
pod *api.Pod
secret *api.Secret
)
if ref := req.Spec.BoundObjectRef; ref != nil {
var uid types.UID
gvk := schema.FromAPIVersionAndKind(ref.APIVersion, ref.Kind)
switch {
case gvk.Group == "" && gvk.Kind == "Pod":
newCtx := newContext(ctx, "pods", ref.Name, gvk)
podObj, err := r.pods.Get(newCtx, ref.Name, &metav1.GetOptions{})
if err != nil {
return nil, err
}
pod = podObj.(*api.Pod)
if name != pod.Spec.ServiceAccountName {
return nil, errors.NewBadRequest(fmt.Sprintf("cannot bind token for serviceaccount %q to pod running with different serviceaccount name.", name))
}
uid = pod.UID
case gvk.Group == "" && gvk.Kind == "Secret":
newCtx := newContext(ctx, "secrets", ref.Name, gvk)
secretObj, err := r.secrets.Get(newCtx, ref.Name, &metav1.GetOptions{})
if err != nil {
return nil, err
}
secret = secretObj.(*api.Secret)
uid = secret.UID
default:
return nil, errors.NewBadRequest(fmt.Sprintf("cannot bind token to object of type %s", gvk.String()))
}
if ref.UID != "" && uid != ref.UID {
return nil, errors.NewConflict(schema.GroupResource{Group: gvk.Group, Resource: gvk.Kind}, ref.Name, fmt.Errorf("the UID in the bound object reference (%s) does not match the UID in record. The object might have been deleted and then recreated", ref.UID))
}
}
if r.maxExpirationSeconds > 0 && req.Spec.ExpirationSeconds > r.maxExpirationSeconds {
//only positive value is valid
warning.AddWarning(ctx, "", fmt.Sprintf("requested expiration of %d seconds shortened to %d seconds", req.Spec.ExpirationSeconds, r.maxExpirationSeconds))
req.Spec.ExpirationSeconds = r.maxExpirationSeconds
}
// Tweak expiration for safe transition of projected service account token.
// Warn (instead of fail) after requested expiration time.
// Fail after hard-coded extended expiration time.
// Only perform the extension when token is pod-bound.
var warnAfter int64
exp := req.Spec.ExpirationSeconds
if r.extendExpiration && pod != nil && req.Spec.ExpirationSeconds == token.WarnOnlyBoundTokenExpirationSeconds && r.isKubeAudiences(req.Spec.Audiences) {
warnAfter = exp
exp = token.ExpirationExtensionSeconds
}
sc, pc := token.Claims(*svcacct, pod, secret, exp, warnAfter, req.Spec.Audiences)
tokdata, err := r.issuer.GenerateToken(sc, pc)
if err != nil {
return nil, fmt.Errorf("failed to generate token: %v", err)
}
// populate status
out := req.DeepCopy()
out.Status = authenticationapi.TokenRequestStatus{
Token: tokdata,
ExpirationTimestamp: metav1.Time{Time: nowTime.Add(time.Duration(out.Spec.ExpirationSeconds) * time.Second)},
}
return out, nil
}
func (r *TokenREST) GroupVersionKind(schema.GroupVersion) schema.GroupVersionKind {
return gvk
}
type getter interface {
Get(ctx context.Context, name string, options *metav1.GetOptions) (runtime.Object, error)
}
// newContext return a copy of ctx in which new RequestInfo is set
func newContext(ctx context.Context, resource, name string, gvk schema.GroupVersionKind) context.Context {
oldInfo, found := genericapirequest.RequestInfoFrom(ctx)
if !found {
return ctx
}
newInfo := genericapirequest.RequestInfo{
IsResourceRequest: true,
Verb: "get",
Namespace: oldInfo.Namespace,
Resource: resource,
Name: name,
Parts: []string{resource, name},
APIGroup: gvk.Group,
APIVersion: gvk.Version,
}
return genericapirequest.WithRequestInfo(ctx, &newInfo)
}
// isKubeAudiences returns true if the tokenaudiences is a strict subset of apiserver audiences.
func (r *TokenREST) isKubeAudiences(tokenAudience []string) bool {
// tokenAudiences must be a strict subset of apiserver audiences
return r.audsSet.HasAll(tokenAudience...)
}