139 lines
4.3 KiB
Go
139 lines
4.3 KiB
Go
/*
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Copyright 2016 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 options
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import (
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"time"
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"github.com/spf13/pflag"
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"k8s.io/apiserver/pkg/authorization/authorizerfactory"
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"k8s.io/apiserver/pkg/server"
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authorizationclient "k8s.io/client-go/kubernetes/typed/authorization/v1beta1"
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"k8s.io/client-go/rest"
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"k8s.io/client-go/tools/clientcmd"
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)
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// DelegatingAuthorizationOptions provides an easy way for composing API servers to delegate their authorization to
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// the root kube API server
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type DelegatingAuthorizationOptions struct {
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// RemoteKubeConfigFile is the file to use to connect to a "normal" kube API server which hosts the
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// SubjectAccessReview.authorization.k8s.io endpoint for checking tokens.
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RemoteKubeConfigFile string
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// AllowCacheTTL is the length of time that a successful authorization response will be cached
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AllowCacheTTL time.Duration
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// DenyCacheTTL is the length of time that an unsuccessful authorization response will be cached.
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// You generally want more responsive, "deny, try again" flows.
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DenyCacheTTL time.Duration
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}
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func NewDelegatingAuthorizationOptions() *DelegatingAuthorizationOptions {
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return &DelegatingAuthorizationOptions{
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// very low for responsiveness, but high enough to handle storms
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AllowCacheTTL: 10 * time.Second,
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DenyCacheTTL: 10 * time.Second,
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}
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}
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func (s *DelegatingAuthorizationOptions) Validate() []error {
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allErrors := []error{}
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return allErrors
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}
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func (s *DelegatingAuthorizationOptions) AddFlags(fs *pflag.FlagSet) {
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if s == nil {
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return
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}
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fs.StringVar(&s.RemoteKubeConfigFile, "authorization-kubeconfig", s.RemoteKubeConfigFile, ""+
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"kubeconfig file pointing at the 'core' kubernetes server with enough rights to create "+
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" subjectaccessreviews.authorization.k8s.io.")
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fs.DurationVar(&s.AllowCacheTTL, "authorization-webhook-cache-authorized-ttl",
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s.AllowCacheTTL,
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"The duration to cache 'authorized' responses from the webhook authorizer.")
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fs.DurationVar(&s.DenyCacheTTL,
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"authorization-webhook-cache-unauthorized-ttl", s.DenyCacheTTL,
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"The duration to cache 'unauthorized' responses from the webhook authorizer.")
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}
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func (s *DelegatingAuthorizationOptions) ApplyTo(c *server.Config) error {
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if s == nil {
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c.Authorizer = authorizerfactory.NewAlwaysAllowAuthorizer()
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return nil
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}
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cfg, err := s.ToAuthorizationConfig()
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if err != nil {
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return err
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}
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authorizer, err := cfg.New()
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if err != nil {
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return err
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}
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c.Authorizer = authorizer
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return nil
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}
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func (s *DelegatingAuthorizationOptions) ToAuthorizationConfig() (authorizerfactory.DelegatingAuthorizerConfig, error) {
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sarClient, err := s.newSubjectAccessReview()
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if err != nil {
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return authorizerfactory.DelegatingAuthorizerConfig{}, err
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}
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ret := authorizerfactory.DelegatingAuthorizerConfig{
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SubjectAccessReviewClient: sarClient,
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AllowCacheTTL: s.AllowCacheTTL,
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DenyCacheTTL: s.DenyCacheTTL,
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}
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return ret, nil
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}
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func (s *DelegatingAuthorizationOptions) newSubjectAccessReview() (authorizationclient.SubjectAccessReviewInterface, error) {
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var clientConfig *rest.Config
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var err error
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if len(s.RemoteKubeConfigFile) > 0 {
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loadingRules := &clientcmd.ClientConfigLoadingRules{ExplicitPath: s.RemoteKubeConfigFile}
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loader := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{})
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clientConfig, err = loader.ClientConfig()
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} else {
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// without the remote kubeconfig file, try to use the in-cluster config. Most addon API servers will
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// use this path
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clientConfig, err = rest.InClusterConfig()
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}
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if err != nil {
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return nil, err
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}
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// set high qps/burst limits since this will effectively limit API server responsiveness
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clientConfig.QPS = 200
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clientConfig.Burst = 400
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client, err := authorizationclient.NewForConfig(clientConfig)
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if err != nil {
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return nil, err
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}
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return client.SubjectAccessReviews(), nil
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}
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