301 lines
13 KiB
Go
301 lines
13 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 certs
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import (
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"crypto/rsa"
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"crypto/x509"
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"fmt"
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"net"
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"os"
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setutil "k8s.io/apimachinery/pkg/util/sets"
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"k8s.io/apimachinery/pkg/util/validation"
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certutil "k8s.io/client-go/util/cert"
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kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
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kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
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"k8s.io/kubernetes/cmd/kubeadm/app/phases/certs/pkiutil"
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"k8s.io/kubernetes/pkg/registry/core/service/ipallocator"
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)
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// TODO: Integration test cases
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// no files exist => create all four files
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// valid ca.{crt,key} exists => create apiserver.{crt,key}
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// valid ca.{crt,key} and apiserver.{crt,key} exists => do nothing
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// invalid ca.{crt,key} exists => error
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// only one of the .crt or .key file exists => error
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// CreatePKIAssets will create and write to disk all PKI assets necessary to establish the control plane.
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// It generates a self-signed CA certificate and a server certificate (signed by the CA)
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func CreatePKIAssets(cfg *kubeadmapi.MasterConfiguration) error {
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pkiDir := cfg.CertificatesDir
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hostname, err := os.Hostname()
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if err != nil {
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return fmt.Errorf("couldn't get the hostname: %v", err)
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}
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_, svcSubnet, err := net.ParseCIDR(cfg.Networking.ServiceSubnet)
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if err != nil {
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return fmt.Errorf("error parsing CIDR %q: %v", cfg.Networking.ServiceSubnet, err)
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}
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// Build the list of SANs
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altNames := getAltNames(cfg.APIServerCertSANs, hostname, cfg.Networking.DNSDomain, svcSubnet)
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// Append the address the API Server is advertising
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altNames.IPs = append(altNames.IPs, net.ParseIP(cfg.API.AdvertiseAddress))
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var caCert *x509.Certificate
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var caKey *rsa.PrivateKey
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// If at least one of them exists, we should try to load them
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// In the case that only one exists, there will most likely be an error anyway
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if pkiutil.CertOrKeyExist(pkiDir, kubeadmconstants.CACertAndKeyBaseName) {
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// Try to load ca.crt and ca.key from the PKI directory
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caCert, caKey, err = pkiutil.TryLoadCertAndKeyFromDisk(pkiDir, kubeadmconstants.CACertAndKeyBaseName)
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if err != nil || caCert == nil || caKey == nil {
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return fmt.Errorf("certificate and/or key existed but they could not be loaded properly")
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}
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// The certificate and key could be loaded, but the certificate is not a CA
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if !caCert.IsCA {
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return fmt.Errorf("certificate and key could be loaded but the certificate is not a CA")
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}
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fmt.Println("[certificates] Using the existing CA certificate and key.")
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} else {
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// The certificate and the key did NOT exist, let's generate them now
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caCert, caKey, err = pkiutil.NewCertificateAuthority()
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if err != nil {
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return fmt.Errorf("failure while generating CA certificate and key [%v]", err)
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}
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if err = pkiutil.WriteCertAndKey(pkiDir, kubeadmconstants.CACertAndKeyBaseName, caCert, caKey); err != nil {
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return fmt.Errorf("failure while saving CA certificate and key [%v]", err)
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}
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fmt.Println("[certificates] Generated CA certificate and key.")
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}
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// If at least one of them exists, we should try to load them
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// In the case that only one exists, there will most likely be an error anyway
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if pkiutil.CertOrKeyExist(pkiDir, kubeadmconstants.APIServerCertAndKeyBaseName) {
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// Try to load apiserver.crt and apiserver.key from the PKI directory
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apiCert, apiKey, err := pkiutil.TryLoadCertAndKeyFromDisk(pkiDir, kubeadmconstants.APIServerCertAndKeyBaseName)
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if err != nil || apiCert == nil || apiKey == nil {
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return fmt.Errorf("certificate and/or key existed but they could not be loaded properly")
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}
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fmt.Println("[certificates] Using the existing API Server certificate and key.")
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} else {
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// The certificate and the key did NOT exist, let's generate them now
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// TODO: Add a test case to verify that this cert has the x509.ExtKeyUsageServerAuth flag
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config := certutil.Config{
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CommonName: "kube-apiserver",
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AltNames: altNames,
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Usages: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
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}
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apiCert, apiKey, err := pkiutil.NewCertAndKey(caCert, caKey, config)
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if err != nil {
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return fmt.Errorf("failure while creating API server key and certificate [%v]", err)
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}
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if err = pkiutil.WriteCertAndKey(pkiDir, kubeadmconstants.APIServerCertAndKeyBaseName, apiCert, apiKey); err != nil {
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return fmt.Errorf("failure while saving API server certificate and key [%v]", err)
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}
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fmt.Println("[certificates] Generated API server certificate and key.")
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fmt.Printf("[certificates] API Server serving cert is signed for DNS names %v and IPs %v\n", altNames.DNSNames, altNames.IPs)
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}
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// If at least one of them exists, we should try to load them
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// In the case that only one exists, there will most likely be an error anyway
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if pkiutil.CertOrKeyExist(pkiDir, kubeadmconstants.APIServerKubeletClientCertAndKeyBaseName) {
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// Try to load apiserver-kubelet-client.crt and apiserver-kubelet-client.key from the PKI directory
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apiCert, apiKey, err := pkiutil.TryLoadCertAndKeyFromDisk(pkiDir, kubeadmconstants.APIServerKubeletClientCertAndKeyBaseName)
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if err != nil || apiCert == nil || apiKey == nil {
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return fmt.Errorf("certificate and/or key existed but they could not be loaded properly")
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}
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fmt.Println("[certificates] Using the existing API Server kubelet client certificate and key.")
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} else {
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// The certificate and the key did NOT exist, let's generate them now
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// TODO: Add a test case to verify that this cert has the x509.ExtKeyUsageClientAuth flag
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config := certutil.Config{
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CommonName: "kube-apiserver-kubelet-client",
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Organization: []string{kubeadmconstants.MastersGroup},
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Usages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
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}
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apiClientCert, apiClientKey, err := pkiutil.NewCertAndKey(caCert, caKey, config)
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if err != nil {
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return fmt.Errorf("failure while creating API server kubelet client key and certificate [%v]", err)
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}
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if err = pkiutil.WriteCertAndKey(pkiDir, kubeadmconstants.APIServerKubeletClientCertAndKeyBaseName, apiClientCert, apiClientKey); err != nil {
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return fmt.Errorf("failure while saving API server kubelet client certificate and key [%v]", err)
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}
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fmt.Println("[certificates] Generated API server kubelet client certificate and key.")
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}
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// If the key exists, we should try to load it
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if pkiutil.CertOrKeyExist(pkiDir, kubeadmconstants.ServiceAccountKeyBaseName) {
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// Try to load sa.key from the PKI directory
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_, err := pkiutil.TryLoadKeyFromDisk(pkiDir, kubeadmconstants.ServiceAccountKeyBaseName)
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if err != nil {
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return fmt.Errorf("certificate and/or key existed but they could not be loaded properly [%v]", err)
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}
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fmt.Println("[certificates] Using the existing service account token signing key.")
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} else {
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// The key does NOT exist, let's generate it now
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saTokenSigningKey, err := certutil.NewPrivateKey()
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if err != nil {
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return fmt.Errorf("failure while creating service account token signing key [%v]", err)
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}
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if err = pkiutil.WriteKey(pkiDir, kubeadmconstants.ServiceAccountKeyBaseName, saTokenSigningKey); err != nil {
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return fmt.Errorf("failure while saving service account token signing key [%v]", err)
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}
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if err = pkiutil.WritePublicKey(pkiDir, kubeadmconstants.ServiceAccountKeyBaseName, &saTokenSigningKey.PublicKey); err != nil {
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return fmt.Errorf("failure while saving service account token signing public key [%v]", err)
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}
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fmt.Println("[certificates] Generated service account token signing key and public key.")
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}
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// front proxy CA and client certs are used to secure a front proxy authenticator which is used to assert identity
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// without the client cert, you cannot make use of the front proxy and the kube-aggregator uses this connection
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// so we generate and enable it unconditionally
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// This is a separte CA, so that front proxy identities cannot hit the API and normal client certs cannot be used
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// as front proxies.
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var frontProxyCACert *x509.Certificate
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var frontProxyCAKey *rsa.PrivateKey
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// If at least one of them exists, we should try to load them
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// In the case that only one exists, there will most likely be an error anyway
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if pkiutil.CertOrKeyExist(pkiDir, kubeadmconstants.FrontProxyCACertAndKeyBaseName) {
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// Try to load front-proxy-ca.crt and front-proxy-ca.key from the PKI directory
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frontProxyCACert, frontProxyCAKey, err = pkiutil.TryLoadCertAndKeyFromDisk(pkiDir, kubeadmconstants.FrontProxyCACertAndKeyBaseName)
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if err != nil || frontProxyCACert == nil || frontProxyCAKey == nil {
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return fmt.Errorf("certificate and/or key existed but they could not be loaded properly")
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}
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// The certificate and key could be loaded, but the certificate is not a CA
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if !frontProxyCACert.IsCA {
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return fmt.Errorf("certificate and key could be loaded but the certificate is not a CA")
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}
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fmt.Println("[certificates] Using the existing front-proxy CA certificate and key.")
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} else {
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// The certificate and the key did NOT exist, let's generate them now
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frontProxyCACert, frontProxyCAKey, err = pkiutil.NewCertificateAuthority()
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if err != nil {
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return fmt.Errorf("failure while generating front-proxy CA certificate and key [%v]", err)
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}
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if err = pkiutil.WriteCertAndKey(pkiDir, kubeadmconstants.FrontProxyCACertAndKeyBaseName, frontProxyCACert, frontProxyCAKey); err != nil {
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return fmt.Errorf("failure while saving front-proxy CA certificate and key [%v]", err)
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}
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fmt.Println("[certificates] Generated front-proxy CA certificate and key.")
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}
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// At this point we have a front proxy CA signing key. We can use that create the front proxy client cert if
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// it doesn't already exist.
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// If at least one of them exists, we should try to load them
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// In the case that only one exists, there will most likely be an error anyway
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if pkiutil.CertOrKeyExist(pkiDir, kubeadmconstants.FrontProxyClientCertAndKeyBaseName) {
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// Try to load apiserver-kubelet-client.crt and apiserver-kubelet-client.key from the PKI directory
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apiCert, apiKey, err := pkiutil.TryLoadCertAndKeyFromDisk(pkiDir, kubeadmconstants.FrontProxyClientCertAndKeyBaseName)
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if err != nil || apiCert == nil || apiKey == nil {
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return fmt.Errorf("certificate and/or key existed but they could not be loaded properly")
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}
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fmt.Println("[certificates] Using the existing front-proxy client certificate and key.")
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} else {
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// The certificate and the key did NOT exist, let's generate them now
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// TODO: Add a test case to verify that this cert has the x509.ExtKeyUsageClientAuth flag
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config := certutil.Config{
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CommonName: "front-proxy-client",
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Usages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
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}
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apiClientCert, apiClientKey, err := pkiutil.NewCertAndKey(frontProxyCACert, frontProxyCAKey, config)
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if err != nil {
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return fmt.Errorf("failure while creating front-proxy client key and certificate [%v]", err)
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}
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if err = pkiutil.WriteCertAndKey(pkiDir, kubeadmconstants.FrontProxyClientCertAndKeyBaseName, apiClientCert, apiClientKey); err != nil {
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return fmt.Errorf("failure while saving front-proxy client certificate and key [%v]", err)
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}
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fmt.Println("[certificates] Generated front-proxy client certificate and key.")
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}
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fmt.Printf("[certificates] Valid certificates and keys now exist in %q\n", pkiDir)
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return nil
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}
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// checkAltNamesExist verifies that the cert is valid for all IPs and DNS names it should be valid for
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func checkAltNamesExist(IPs []net.IP, DNSNames []string, altNames certutil.AltNames) bool {
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dnsset := setutil.NewString(DNSNames...)
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for _, dnsNameThatShouldExist := range altNames.DNSNames {
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if !dnsset.Has(dnsNameThatShouldExist) {
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return false
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}
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}
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for _, ipThatShouldExist := range altNames.IPs {
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found := false
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for _, ip := range IPs {
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if ip.Equal(ipThatShouldExist) {
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found = true
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break
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}
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}
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if !found {
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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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// getAltNames builds an AltNames object for the certutil to use when generating the certificates
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func getAltNames(cfgAltNames []string, hostname, dnsdomain string, svcSubnet *net.IPNet) certutil.AltNames {
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altNames := certutil.AltNames{
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DNSNames: []string{
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hostname,
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"kubernetes",
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"kubernetes.default",
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"kubernetes.default.svc",
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fmt.Sprintf("kubernetes.default.svc.%s", dnsdomain),
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},
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}
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// Populate IPs/DNSNames from AltNames
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for _, altname := range cfgAltNames {
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if ip := net.ParseIP(altname); ip != nil {
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altNames.IPs = append(altNames.IPs, ip)
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} else if len(validation.IsDNS1123Subdomain(altname)) == 0 {
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altNames.DNSNames = append(altNames.DNSNames, altname)
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}
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}
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// and lastly, extract the internal IP address for the API server
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internalAPIServerVirtualIP, err := ipallocator.GetIndexedIP(svcSubnet, 1)
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if err != nil {
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fmt.Printf("[certs] WARNING: Unable to get first IP address from the given CIDR (%s): %v\n", svcSubnet.String(), err)
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}
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altNames.IPs = append(altNames.IPs, internalAPIServerVirtualIP)
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return altNames
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}
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