141 lines
4.6 KiB
Go
141 lines
4.6 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 webhook implements the authenticator.Token interface using HTTP webhooks.
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package webhook
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import (
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"context"
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"time"
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"k8s.io/klog"
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authentication "k8s.io/api/authentication/v1beta1"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/apiserver/pkg/authentication/authenticator"
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"k8s.io/apiserver/pkg/authentication/user"
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"k8s.io/apiserver/pkg/util/webhook"
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"k8s.io/client-go/kubernetes/scheme"
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authenticationclient "k8s.io/client-go/kubernetes/typed/authentication/v1beta1"
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)
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var (
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groupVersions = []schema.GroupVersion{authentication.SchemeGroupVersion}
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)
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const retryBackoff = 500 * time.Millisecond
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// Ensure WebhookTokenAuthenticator implements the authenticator.Token interface.
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var _ authenticator.Token = (*WebhookTokenAuthenticator)(nil)
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type WebhookTokenAuthenticator struct {
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tokenReview authenticationclient.TokenReviewInterface
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initialBackoff time.Duration
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}
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// NewFromInterface creates a webhook authenticator using the given tokenReview
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// client. It is recommend to wrap this authenticator with the token cache
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// authenticator implemented in
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// k8s.io/apiserver/pkg/authentication/token/cache.
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func NewFromInterface(tokenReview authenticationclient.TokenReviewInterface) (*WebhookTokenAuthenticator, error) {
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return newWithBackoff(tokenReview, retryBackoff)
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}
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// New creates a new WebhookTokenAuthenticator from the provided kubeconfig file.
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func New(kubeConfigFile string) (*WebhookTokenAuthenticator, error) {
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tokenReview, err := tokenReviewInterfaceFromKubeconfig(kubeConfigFile)
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if err != nil {
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return nil, err
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}
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return newWithBackoff(tokenReview, retryBackoff)
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}
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// newWithBackoff allows tests to skip the sleep.
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func newWithBackoff(tokenReview authenticationclient.TokenReviewInterface, initialBackoff time.Duration) (*WebhookTokenAuthenticator, error) {
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return &WebhookTokenAuthenticator{tokenReview, initialBackoff}, nil
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}
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// AuthenticateToken implements the authenticator.Token interface.
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func (w *WebhookTokenAuthenticator) AuthenticateToken(ctx context.Context, token string) (*authenticator.Response, bool, error) {
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r := &authentication.TokenReview{
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Spec: authentication.TokenReviewSpec{Token: token},
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}
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var (
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result *authentication.TokenReview
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err error
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)
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webhook.WithExponentialBackoff(w.initialBackoff, func() error {
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result, err = w.tokenReview.Create(r)
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return err
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})
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if err != nil {
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// An error here indicates bad configuration or an outage. Log for debugging.
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klog.Errorf("Failed to make webhook authenticator request: %v", err)
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return nil, false, err
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}
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r.Status = result.Status
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if !r.Status.Authenticated {
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return nil, false, nil
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}
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var extra map[string][]string
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if r.Status.User.Extra != nil {
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extra = map[string][]string{}
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for k, v := range r.Status.User.Extra {
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extra[k] = v
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}
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}
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return &authenticator.Response{
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User: &user.DefaultInfo{
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Name: r.Status.User.Username,
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UID: r.Status.User.UID,
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Groups: r.Status.User.Groups,
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Extra: extra,
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},
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}, true, nil
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}
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// tokenReviewInterfaceFromKubeconfig builds a client from the specified kubeconfig file,
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// and returns a TokenReviewInterface that uses that client. Note that the client submits TokenReview
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// requests to the exact path specified in the kubeconfig file, so arbitrary non-API servers can be targeted.
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func tokenReviewInterfaceFromKubeconfig(kubeConfigFile string) (authenticationclient.TokenReviewInterface, error) {
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localScheme := runtime.NewScheme()
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if err := scheme.AddToScheme(localScheme); err != nil {
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return nil, err
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}
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if err := localScheme.SetVersionPriority(groupVersions...); err != nil {
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return nil, err
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}
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gw, err := webhook.NewGenericWebhook(localScheme, scheme.Codecs, kubeConfigFile, groupVersions, 0)
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if err != nil {
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return nil, err
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}
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return &tokenReviewClient{gw}, nil
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}
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type tokenReviewClient struct {
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w *webhook.GenericWebhook
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}
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func (t *tokenReviewClient) Create(tokenReview *authentication.TokenReview) (*authentication.TokenReview, error) {
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result := &authentication.TokenReview{}
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err := t.w.RestClient.Post().Body(tokenReview).Do().Into(result)
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return result, err
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}
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