139 lines
3.8 KiB
Go
139 lines
3.8 KiB
Go
/*
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Copyright 2020 The Kruise Authors.
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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 writer
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import (
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"crypto/tls"
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"crypto/x509"
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"encoding/pem"
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"errors"
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"time"
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"k8s.io/klog/v2"
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"github.com/openkruise/rollouts/pkg/webhook/util/generator"
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)
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const (
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// CAKeyName is the name of the CA private key
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CAKeyName = "ca-key.pem"
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// CACertName is the name of the CA certificate
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CACertName = "ca-cert.pem"
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// ServerKeyName is the name of the server private key
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ServerKeyName = "key.pem"
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ServerKeyName2 = "tls.key"
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// ServerCertName is the name of the serving certificate
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ServerCertName = "cert.pem"
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ServerCertName2 = "tls.crt"
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)
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// CertWriter provides method to handle webhooks.
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type CertWriter interface {
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// EnsureCert provisions the cert for the webhookClientConfig.
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EnsureCert(dnsName string) (*generator.Artifacts, bool, error)
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}
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// handleCommon ensures the given webhook has a proper certificate.
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// It uses the given certReadWriter to read and (or) write the certificate.
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func handleCommon(dnsName string, ch certReadWriter) (*generator.Artifacts, bool, error) {
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if len(dnsName) == 0 {
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return nil, false, errors.New("dnsName should not be empty")
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}
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if ch == nil {
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return nil, false, errors.New("certReaderWriter should not be nil")
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}
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certs, changed, err := createIfNotExists(ch)
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if err != nil {
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return nil, changed, err
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}
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// Recreate the cert if it's invalid.
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valid := validCert(certs, dnsName)
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if !valid {
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klog.Info("cert is invalid or expiring, regenerating a new one")
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certs, err = ch.overwrite(certs.ResourceVersion)
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if err != nil {
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return nil, false, err
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}
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changed = true
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}
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return certs, changed, nil
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}
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func createIfNotExists(ch certReadWriter) (*generator.Artifacts, bool, error) {
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// Try to read first
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certs, err := ch.read()
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if isNotFound(err) {
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// Create if not exists
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certs, err = ch.write()
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switch {
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// This may happen if there is another racer.
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case isAlreadyExists(err):
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certs, err = ch.read()
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return certs, true, err
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default:
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return certs, true, err
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}
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}
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return certs, false, err
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}
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// certReadWriter provides methods for reading and writing certificates.
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type certReadWriter interface {
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// read reads a webhook name and returns the certs for it.
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read() (*generator.Artifacts, error)
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// write writes the certs and return the certs it wrote.
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write() (*generator.Artifacts, error)
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// overwrite overwrites the existing certs and return the certs it wrote.
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overwrite(resourceVersion string) (*generator.Artifacts, error)
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}
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func validCert(certs *generator.Artifacts, dnsName string) bool {
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if certs == nil || certs.Cert == nil || certs.Key == nil || certs.CACert == nil {
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return false
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}
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// Verify key and cert are valid pair
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_, err := tls.X509KeyPair(certs.Cert, certs.Key)
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if err != nil {
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return false
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}
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// Verify cert is good for desired DNS name and signed by CA and will be valid for desired period of time.
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pool := x509.NewCertPool()
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if !pool.AppendCertsFromPEM(certs.CACert) {
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return false
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}
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block, _ := pem.Decode(certs.Cert)
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if block == nil {
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return false
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}
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cert, err := x509.ParseCertificate(block.Bytes)
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if err != nil {
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return false
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}
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ops := x509.VerifyOptions{
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DNSName: dnsName,
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Roots: pool,
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CurrentTime: time.Now().AddDate(0, 6, 0),
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}
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_, err = cert.Verify(ops)
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return err == nil
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}
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