token.go

/*
Copyright 2019 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 controllers

import (
	"time"

	"github.com/pkg/errors"
	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	corev1 "k8s.io/client-go/kubernetes/typed/core/v1"
	bootstrapapi "k8s.io/cluster-bootstrap/token/api"
	bootstraputil "k8s.io/cluster-bootstrap/token/util"
	clusterv1 "sigs.k8s.io/cluster-api/api/v1alpha2"
	capiremote "sigs.k8s.io/cluster-api/controllers/remote"
	"sigs.k8s.io/controller-runtime/pkg/client"
)

var (
	// DefaultTokenTTL is the amount of time a bootstrap token (and therefore a KubeadmConfig) will be valid
	DefaultTokenTTL = 15 * time.Minute
)

// ClusterSecretsClientFactory support creation of secrets client for clusters
type ClusterSecretsClientFactory struct{}

// NewSecretsClient returns a new client supporting SecretInterface for the cluster
func (f ClusterSecretsClientFactory) NewSecretsClient(client client.Client, cluster *clusterv1.Cluster) (corev1.SecretInterface, error) {
	remoteClient, err := capiremote.NewClusterClient(client, cluster)
	if err != nil {
		return nil, err
	}

	corev1Client, err := remoteClient.CoreV1()
	if err != nil {
		return nil, err
	}

	return corev1Client.Secrets(metav1.NamespaceSystem), nil
}

// createToken attempts to create a token with the given ID.
func createToken(client corev1.SecretInterface) (string, error) {
	token, err := bootstraputil.GenerateBootstrapToken()
	if err != nil {
		return "", errors.Wrap(err, "unable to generate bootstrap token")
	}

	substrs := bootstraputil.BootstrapTokenRegexp.FindStringSubmatch(token)
	if len(substrs) != 3 {
		return "", errors.Errorf("the bootstrap token %q was not of the form %q", token, bootstrapapi.BootstrapTokenPattern)
	}
	tokenID := substrs[1]
	tokenSecret := substrs[2]

	secretName := bootstraputil.BootstrapTokenSecretName(tokenID)
	secretToken := &v1.Secret{
		ObjectMeta: metav1.ObjectMeta{
			Name:      secretName,
			Namespace: metav1.NamespaceSystem,
		},
		Type: bootstrapapi.SecretTypeBootstrapToken,
		Data: map[string][]byte{
			bootstrapapi.BootstrapTokenIDKey:               []byte(tokenID),
			bootstrapapi.BootstrapTokenSecretKey:           []byte(tokenSecret),
			bootstrapapi.BootstrapTokenExpirationKey:       []byte(time.Now().UTC().Add(DefaultTokenTTL).Format(time.RFC3339)),
			bootstrapapi.BootstrapTokenUsageSigningKey:     []byte("true"),
			bootstrapapi.BootstrapTokenUsageAuthentication: []byte("true"),
			bootstrapapi.BootstrapTokenExtraGroupsKey:      []byte("system:bootstrappers:kubeadm:default-node-token"),
			bootstrapapi.BootstrapTokenDescriptionKey:      []byte("token generated by cluster-api-bootstrap-provider-kubeadm"),
		},
	}

	if _, err = client.Create(secretToken); err != nil {
		return "", err
	}
	return token, nil
}

// refreshToken extends the TTL for an existing token
func refreshToken(client corev1.SecretInterface, token string) error {
	substrs := bootstraputil.BootstrapTokenRegexp.FindStringSubmatch(token)
	if len(substrs) != 3 {
		return errors.Errorf("the bootstrap token %q was not of the form %q", token, bootstrapapi.BootstrapTokenPattern)
	}
	tokenID := substrs[1]

	secretName := bootstraputil.BootstrapTokenSecretName(tokenID)
	secret, err := client.Get(secretName, metav1.GetOptions{})
	if err != nil {
		return err
	}

	if secret.Data == nil {
		return errors.Errorf("Invalid bootstrap secret %q, remove the token from the kubadm config to re-create", secretName)
	}
	secret.Data[bootstrapapi.BootstrapTokenExpirationKey] = []byte(time.Now().UTC().Add(DefaultTokenTTL).Format(time.RFC3339))

	_, err = client.Update(secret)
	return err
}