/
certRenewer.go
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/
certRenewer.go
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// This file may have been modified by vArmor Authors. ("vArmor Modifications").
// All vArmor Modifications are Copyright 2022 vArmor Authors.
//
// Copyright 2021 Kyverno 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 tls
import (
"context"
"crypto/tls"
"crypto/x509"
"encoding/pem"
"fmt"
"time"
"github.com/cenkalti/backoff"
"github.com/go-logr/logr"
"github.com/pkg/errors"
v1 "k8s.io/api/core/v1"
k8errors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
appsv1 "k8s.io/client-go/kubernetes/typed/apps/v1"
corev1 "k8s.io/client-go/kubernetes/typed/core/v1"
"k8s.io/client-go/rest"
"github.com/bytedance/vArmor/internal/config"
)
const (
SelfSignedAnnotation string = "self-signed-cert"
RootCAKey string = "rootCA.crt"
rollingUpdateAnnotation string = "cert.varmor.org/force-rolling-update"
)
// CertRenewer creates rootCA and pem pair to register
// webhook configurations and webhook server
// renews RootCA at the given interval.
type CertRenewer struct {
clientConfig *rest.Config
secretInterface corev1.SecretInterface
deploymentInterface appsv1.DeploymentInterface
certRenewalInterval time.Duration
certValidityDuration time.Duration
managerIP string
debug bool
log logr.Logger
}
// NewCertRenewer returns an instance of CertRenewer.
func NewCertRenewer(clientConfig *rest.Config, secretInterface corev1.SecretInterface, deploymentInterface appsv1.DeploymentInterface, certRenewalInterval, certValidityDuration time.Duration, managerIP string, debug bool, log logr.Logger) *CertRenewer {
return &CertRenewer{
clientConfig: clientConfig,
secretInterface: secretInterface,
deploymentInterface: deploymentInterface,
certRenewalInterval: certRenewalInterval,
certValidityDuration: certValidityDuration,
managerIP: managerIP,
debug: debug,
log: log,
}
}
// ValidCert validates the CA Cert.
func (c *CertRenewer) ValidCert(certProps CertificateProps) (bool, error) {
logger := c.log.WithName("ValidCert")
secretName := GenerateRootCASecretName(certProps)
rootCA, err := ReadRootCASecret(c.secretInterface, secretName)
if err != nil {
return false, err
}
secretName = GenerateTLSPairSecretName(certProps)
tlsPair, err := ReadTLSPair(c.secretInterface, secretName)
if err != nil {
return false, err
}
// build cert pool
pool := x509.NewCertPool()
caPem, _ := pem.Decode(rootCA)
if caPem == nil {
logger.Error(err, "bad certificate")
return false, nil
}
cac, err := x509.ParseCertificate(caPem.Bytes)
if err != nil {
logger.Error(err, "failed to parse CA cert")
return false, nil
}
pool.AddCert(cac)
// valid PEM pair
_, err = tls.X509KeyPair(tlsPair.Certificate, tlsPair.PrivateKey)
if err != nil {
logger.Error(err, "invalid PEM pair")
return false, nil
}
certPem, _ := pem.Decode(tlsPair.Certificate)
if certPem == nil {
logger.Error(err, "bad private key")
return false, nil
}
cert, err := x509.ParseCertificate(certPem.Bytes)
if err != nil {
logger.Error(err, "failed to parse cert")
return false, nil
}
if _, err = cert.Verify(x509.VerifyOptions{
Roots: pool,
CurrentTime: time.Now().Add(c.certRenewalInterval),
}); err != nil {
logger.Error(err, "invalid cert")
return false, nil
}
return true, nil
}
// WriteCACertToSecret stores the CA cert in secret.
func (c *CertRenewer) WriteCACertToSecret(caPEM *PemPair, secretName string) error {
secret, err := c.secretInterface.Get(context.Background(), secretName, metav1.GetOptions{})
if err == nil {
secret.Annotations = map[string]string{SelfSignedAnnotation: "true"}
secret.Data = map[string][]byte{RootCAKey: caPEM.Certificate}
secret.Type = v1.SecretTypeOpaque
_, err = c.secretInterface.Update(context.Background(), secret, metav1.UpdateOptions{})
return err
} else {
if k8errors.IsNotFound(err) {
secret := &v1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: secretName,
Annotations: map[string]string{
SelfSignedAnnotation: "true",
},
},
Data: map[string][]byte{
RootCAKey: caPEM.Certificate,
},
Type: v1.SecretTypeOpaque,
}
_, err = c.secretInterface.Create(context.Background(), secret, metav1.CreateOptions{})
}
}
return err
}
// WriteTLSPairToSecret writes the pair of TLS certificate and key to the specified secret.
func (c *CertRenewer) WriteTLSPairToSecret(pemPair *PemPair, secretName string) error {
secret, err := c.secretInterface.Get(context.Background(), secretName, metav1.GetOptions{})
if err == nil {
secret.Data = map[string][]byte{
v1.TLSCertKey: pemPair.Certificate,
v1.TLSPrivateKeyKey: pemPair.PrivateKey,
}
secret.Type = v1.SecretTypeTLS
_, err = c.secretInterface.Update(context.Background(), secret, metav1.UpdateOptions{})
} else {
if k8errors.IsNotFound(err) {
secret := &v1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: secretName,
},
Data: map[string][]byte{
v1.TLSCertKey: pemPair.Certificate,
v1.TLSPrivateKeyKey: pemPair.PrivateKey,
},
Type: v1.SecretTypeTLS,
}
_, err = c.secretInterface.Create(context.Background(), secret, metav1.CreateOptions{})
}
}
return err
}
// buildTLSPemPairAndWriteToSecrets Issues TLS certificate for webhook server using self-signed CA cert.
// Returns signed and approved TLS certificate in PEM format.
func (c *CertRenewer) buildTLSPemPairAndWriteToSecrets(props CertificateProps) (*PemPair, error) {
caCert, caPEM, err := GenerateCACert(c.certValidityDuration)
if err != nil {
return nil, err
}
secretName := GenerateRootCASecretName(props)
if err := c.WriteCACertToSecret(caPEM, secretName); err != nil {
return nil, fmt.Errorf("failed to write or update CA cert to secret %s: %v", secretName, err)
}
tlsPair, err := GenerateCertPem(caCert, props, c.certValidityDuration, c.managerIP, c.debug)
if err != nil {
return nil, err
}
secretName = GenerateTLSPairSecretName(props)
if err = c.WriteTLSPairToSecret(tlsPair, secretName); err != nil {
return nil, fmt.Errorf("unable to save TLS pair to the secret %s: %v", secretName, err)
}
return tlsPair, nil
}
// InitTLSPemPair Loads or creates PEM private key and TLS certificate for webhook server.
// Created pair is stored in cluster's secret.
// Returns struct with key/certificate pair.
func (c *CertRenewer) InitTLSPemPair() (*PemPair, error) {
logger := c.log.WithName("InitTLSPemPair")
certProps, err := GetTLSCertProps(c.clientConfig)
if err != nil {
return nil, err
}
valid, err := c.ValidCert(certProps)
if err == nil && valid {
logger.Info("using existing TLS pair")
tlsPair, err := ReadTLSPair(c.secretInterface, GenerateTLSPairSecretName(certProps))
return tlsPair, err
}
logger.Info("buiding new root CA and TLS pair")
return c.buildTLSPemPairAndWriteToSecrets(certProps)
}
// RollingUpdate triggers a rolling update of varmor-manager pod.
// It is used when the rootCA is renewed, the restart of
// varmor-manager pod will register webhook server with new cert.
func (c *CertRenewer) RollingUpdateVarmorManager() error {
logger := c.log.WithName("RollingUpdateVarmorManager")
update := func() error {
deploy, err := c.deploymentInterface.Get(context.Background(), config.ManagerName, metav1.GetOptions{})
if err != nil {
return errors.Wrap(err, "failed to find manager")
}
if IsVarmorManagerInRollingUpdate(deploy) {
logger.Info("manager is in rolling update, won't trigger the update again")
return nil
}
if deploy.Spec.Template.Annotations == nil {
deploy.Spec.Template.Annotations = make(map[string]string)
}
deploy.Spec.Template.Annotations[rollingUpdateAnnotation] = time.Now().Format(time.RFC3339)
if _, err = c.deploymentInterface.Update(context.Background(), deploy, metav1.UpdateOptions{}); err != nil {
return errors.Wrap(err, "failed to update manager")
}
return nil
}
exbackoff := &backoff.ExponentialBackOff{
InitialInterval: 500 * time.Millisecond,
RandomizationFactor: 0.5,
Multiplier: 1.5,
MaxInterval: time.Second,
MaxElapsedTime: 3 * time.Second,
Clock: backoff.SystemClock,
}
exbackoff.Reset()
return backoff.Retry(update, exbackoff)
}