cd91e59f7c
This change updates the CSR API to add a new, optional field called expirationSeconds. This field is a request to the signer for the maximum duration the client wishes the cert to have. The signer is free to ignore this request based on its own internal policy. The signers built-in to KCM will honor this field if it is not set to a value greater than --cluster-signing-duration. The minimum allowed value for this field is 600 seconds (ten minutes). This change will help enforce safer durations for certificates in the Kube ecosystem and will help related projects such as cert-manager with their migration to the Kube CSR API. Future enhancements may update the Kubelet to take advantage of this field when it is configured in a way that can tolerate shorter certificate lifespans with regular rotation. Signed-off-by: Monis Khan <mok@vmware.com>
117 lines
7.8 KiB
Go
117 lines
7.8 KiB
Go
/*
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Copyright 2018 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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"fmt"
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"github.com/spf13/pflag"
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csrsigningconfig "k8s.io/kubernetes/pkg/controller/certificates/signer/config"
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)
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// CSRSigningControllerOptions holds the CSRSigningController options.
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type CSRSigningControllerOptions struct {
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*csrsigningconfig.CSRSigningControllerConfiguration
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}
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// AddFlags adds flags related to CSRSigningController for controller manager to the specified FlagSet.
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func (o *CSRSigningControllerOptions) AddFlags(fs *pflag.FlagSet) {
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if o == nil {
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return
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}
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fs.StringVar(&o.ClusterSigningCertFile, "cluster-signing-cert-file", o.ClusterSigningCertFile, "Filename containing a PEM-encoded X509 CA certificate used to issue cluster-scoped certificates. If specified, no more specific --cluster-signing-* flag may be specified.")
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fs.StringVar(&o.ClusterSigningKeyFile, "cluster-signing-key-file", o.ClusterSigningKeyFile, "Filename containing a PEM-encoded RSA or ECDSA private key used to sign cluster-scoped certificates. If specified, no more specific --cluster-signing-* flag may be specified.")
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fs.StringVar(&o.KubeletServingSignerConfiguration.CertFile, "cluster-signing-kubelet-serving-cert-file", o.KubeletServingSignerConfiguration.CertFile, "Filename containing a PEM-encoded X509 CA certificate used to issue certificates for the kubernetes.io/kubelet-serving signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.KubeletServingSignerConfiguration.KeyFile, "cluster-signing-kubelet-serving-key-file", o.KubeletServingSignerConfiguration.KeyFile, "Filename containing a PEM-encoded RSA or ECDSA private key used to sign certificates for the kubernetes.io/kubelet-serving signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.KubeletClientSignerConfiguration.CertFile, "cluster-signing-kubelet-client-cert-file", o.KubeletClientSignerConfiguration.CertFile, "Filename containing a PEM-encoded X509 CA certificate used to issue certificates for the kubernetes.io/kube-apiserver-client-kubelet signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.KubeletClientSignerConfiguration.KeyFile, "cluster-signing-kubelet-client-key-file", o.KubeletClientSignerConfiguration.KeyFile, "Filename containing a PEM-encoded RSA or ECDSA private key used to sign certificates for the kubernetes.io/kube-apiserver-client-kubelet signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.KubeAPIServerClientSignerConfiguration.CertFile, "cluster-signing-kube-apiserver-client-cert-file", o.KubeAPIServerClientSignerConfiguration.CertFile, "Filename containing a PEM-encoded X509 CA certificate used to issue certificates for the kubernetes.io/kube-apiserver-client signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.KubeAPIServerClientSignerConfiguration.KeyFile, "cluster-signing-kube-apiserver-client-key-file", o.KubeAPIServerClientSignerConfiguration.KeyFile, "Filename containing a PEM-encoded RSA or ECDSA private key used to sign certificates for the kubernetes.io/kube-apiserver-client signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.LegacyUnknownSignerConfiguration.CertFile, "cluster-signing-legacy-unknown-cert-file", o.LegacyUnknownSignerConfiguration.CertFile, "Filename containing a PEM-encoded X509 CA certificate used to issue certificates for the kubernetes.io/legacy-unknown signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.StringVar(&o.LegacyUnknownSignerConfiguration.KeyFile, "cluster-signing-legacy-unknown-key-file", o.LegacyUnknownSignerConfiguration.KeyFile, "Filename containing a PEM-encoded RSA or ECDSA private key used to sign certificates for the kubernetes.io/legacy-unknown signer. If specified, --cluster-signing-{cert,key}-file must not be set.")
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fs.DurationVar(&o.ClusterSigningDuration.Duration, "cluster-signing-duration", o.ClusterSigningDuration.Duration, "The max length of duration signed certificates will be given. Individual CSRs may request shorter certs by setting spec.expirationSeconds.")
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fs.DurationVar(&o.ClusterSigningDuration.Duration, "experimental-cluster-signing-duration", o.ClusterSigningDuration.Duration, "The max length of duration signed certificates will be given. Individual CSRs may request shorter certs by setting spec.expirationSeconds.")
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fs.MarkDeprecated("experimental-cluster-signing-duration", "use --cluster-signing-duration")
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}
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// ApplyTo fills up CSRSigningController config with options.
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func (o *CSRSigningControllerOptions) ApplyTo(cfg *csrsigningconfig.CSRSigningControllerConfiguration) error {
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if o == nil {
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return nil
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}
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cfg.ClusterSigningCertFile = o.ClusterSigningCertFile
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cfg.ClusterSigningKeyFile = o.ClusterSigningKeyFile
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cfg.KubeletServingSignerConfiguration = o.KubeletServingSignerConfiguration
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cfg.KubeletClientSignerConfiguration = o.KubeletClientSignerConfiguration
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cfg.KubeAPIServerClientSignerConfiguration = o.KubeAPIServerClientSignerConfiguration
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cfg.LegacyUnknownSignerConfiguration = o.LegacyUnknownSignerConfiguration
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cfg.ClusterSigningDuration = o.ClusterSigningDuration
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return nil
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}
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// Validate checks validation of CSRSigningControllerOptions.
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func (o *CSRSigningControllerOptions) Validate() []error {
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if o == nil {
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return nil
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}
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errs := []error{}
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if err := csrSigningFilesValid(o.KubeletServingSignerConfiguration); err != nil {
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errs = append(errs, fmt.Errorf("%q: %v", "cluster-signing-kubelet-serving", err))
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}
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if err := csrSigningFilesValid(o.KubeletClientSignerConfiguration); err != nil {
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errs = append(errs, fmt.Errorf("%q: %v", "cluster-signing-kube-apiserver-client", err))
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}
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if err := csrSigningFilesValid(o.KubeAPIServerClientSignerConfiguration); err != nil {
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errs = append(errs, fmt.Errorf("%q: %v", "cluster-signing-kube-apiserver", err))
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}
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if err := csrSigningFilesValid(o.LegacyUnknownSignerConfiguration); err != nil {
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errs = append(errs, fmt.Errorf("%q: %v", "cluster-signing-legacy-unknown", err))
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}
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singleSigningFile := len(o.ClusterSigningCertFile) > 0 || len(o.ClusterSigningKeyFile) > 0
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anySpecificFilesSet := len(o.KubeletServingSignerConfiguration.CertFile) > 0 || len(o.KubeletServingSignerConfiguration.KeyFile) > 0 ||
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len(o.KubeletClientSignerConfiguration.CertFile) > 0 || len(o.KubeletClientSignerConfiguration.KeyFile) > 0 ||
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len(o.KubeAPIServerClientSignerConfiguration.CertFile) > 0 || len(o.KubeAPIServerClientSignerConfiguration.KeyFile) > 0 ||
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len(o.LegacyUnknownSignerConfiguration.CertFile) > 0 || len(o.LegacyUnknownSignerConfiguration.KeyFile) > 0
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if singleSigningFile && anySpecificFilesSet {
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errs = append(errs, fmt.Errorf("cannot specify --cluster-signing-{cert,key}-file and other --cluster-signing-*-file flags at the same time"))
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}
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return errs
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}
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// both must be specified or both must be empty
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func csrSigningFilesValid(config csrsigningconfig.CSRSigningConfiguration) error {
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switch {
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case (len(config.CertFile) == 0) && (len(config.KeyFile) == 0):
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return nil
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case (len(config.CertFile) != 0) && (len(config.KeyFile) != 0):
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return nil
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case (len(config.CertFile) == 0) && (len(config.KeyFile) != 0):
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return fmt.Errorf("cannot specify key without cert")
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case (len(config.CertFile) != 0) && (len(config.KeyFile) == 0):
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return fmt.Errorf("cannot specify cert without key")
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}
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return fmt.Errorf("math broke")
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}
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