132 lines
3.7 KiB
Go
132 lines
3.7 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 approver implements an automated approver for kubelet certificates.
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package approver
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import (
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"fmt"
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"reflect"
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"strings"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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capi "k8s.io/kubernetes/pkg/apis/certificates/v1beta1"
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"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
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certificatesinformers "k8s.io/kubernetes/pkg/client/informers/informers_generated/externalversions/certificates/v1beta1"
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"k8s.io/kubernetes/pkg/controller/certificates"
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)
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func NewCSRApprovingController(
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client clientset.Interface,
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csrInformer certificatesinformers.CertificateSigningRequestInformer,
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approveAllKubeletCSRsForGroup string,
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) (*certificates.CertificateController, error) {
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approver := &groupApprover{
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approveAllKubeletCSRsForGroup: approveAllKubeletCSRsForGroup,
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client: client,
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}
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return certificates.NewCertificateController(
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client,
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csrInformer,
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approver.handle,
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)
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}
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// groupApprover implements AutoApprover for signing Kubelet certificates.
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type groupApprover struct {
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approveAllKubeletCSRsForGroup string
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client clientset.Interface
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}
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func (ga *groupApprover) handle(csr *capi.CertificateSigningRequest) error {
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// short-circuit if we're already approved or denied
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if approved, denied := certificates.GetCertApprovalCondition(&csr.Status); approved || denied {
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return nil
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}
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csr, err := ga.autoApprove(csr)
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if err != nil {
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return fmt.Errorf("error auto approving csr: %v", err)
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}
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_, err = ga.client.Certificates().CertificateSigningRequests().UpdateApproval(csr)
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if err != nil {
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return fmt.Errorf("error updating approval for csr: %v", err)
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}
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return nil
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}
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func (cc *groupApprover) autoApprove(csr *capi.CertificateSigningRequest) (*capi.CertificateSigningRequest, error) {
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isKubeletBootstrapGroup := false
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for _, g := range csr.Spec.Groups {
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if g == cc.approveAllKubeletCSRsForGroup {
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isKubeletBootstrapGroup = true
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break
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}
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}
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if !isKubeletBootstrapGroup {
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return csr, nil
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}
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x509cr, err := capi.ParseCSR(csr)
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if err != nil {
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utilruntime.HandleError(fmt.Errorf("unable to parse csr %q: %v", csr.Name, err))
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return csr, nil
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}
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if !reflect.DeepEqual([]string{"system:nodes"}, x509cr.Subject.Organization) {
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return csr, nil
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}
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if !strings.HasPrefix(x509cr.Subject.CommonName, "system:node:") {
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return csr, nil
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}
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if len(x509cr.DNSNames)+len(x509cr.EmailAddresses)+len(x509cr.IPAddresses) != 0 {
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return csr, nil
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}
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if !hasExactUsages(csr, kubeletClientUsages) {
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return csr, nil
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}
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csr.Status.Conditions = append(csr.Status.Conditions, capi.CertificateSigningRequestCondition{
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Type: capi.CertificateApproved,
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Reason: "AutoApproved",
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Message: "Auto approving of all kubelet CSRs is enabled on the controller manager",
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})
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return csr, nil
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}
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var kubeletClientUsages = []capi.KeyUsage{
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capi.UsageKeyEncipherment,
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capi.UsageDigitalSignature,
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capi.UsageClientAuth,
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}
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func hasExactUsages(csr *capi.CertificateSigningRequest, usages []capi.KeyUsage) bool {
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if len(usages) != len(csr.Spec.Usages) {
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return false
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}
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usageMap := map[capi.KeyUsage]struct{}{}
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for _, u := range usages {
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usageMap[u] = struct{}{}
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}
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for _, u := range csr.Spec.Usages {
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if _, ok := usageMap[u]; !ok {
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return false
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}
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}
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return true
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}
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