kubernetes/pkg/controller/certificates/authority/authority.go
Monis Khan 7e891e5d6c
csr: correctly handle backdating of short lived certs
This change updates the backdating logic to only be applied to the
NotBefore date and not the NotAfter date when the certificate is
short lived. Thus when such a certificate is issued, it will not be
immediately expired.  Long lived certificates continue to have the
same lifetime as before.

Consolidated all certificate lifetime logic into the
PermissiveSigningPolicy.policy method.

Signed-off-by: Monis Khan <mok@vmware.com>
2021-06-23 15:36:11 -04:00

79 lines
2.5 KiB
Go

/*
Copyright 2019 The Kubernetes 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 authority
import (
"crypto"
"crypto/rand"
"crypto/x509"
"fmt"
"math/big"
)
var serialNumberLimit = new(big.Int).Lsh(big.NewInt(1), 128)
// CertificateAuthority implements a certificate authority that supports policy
// based signing. It's used by the signing controller.
type CertificateAuthority struct {
// RawCert is an optional field to determine if signing cert/key pairs have changed
RawCert []byte
// RawKey is an optional field to determine if signing cert/key pairs have changed
RawKey []byte
Certificate *x509.Certificate
PrivateKey crypto.Signer
}
// Sign signs a certificate request, applying a SigningPolicy and returns a DER
// encoded x509 certificate.
func (ca *CertificateAuthority) Sign(crDER []byte, policy SigningPolicy) ([]byte, error) {
cr, err := x509.ParseCertificateRequest(crDER)
if err != nil {
return nil, fmt.Errorf("unable to parse certificate request: %v", err)
}
if err := cr.CheckSignature(); err != nil {
return nil, fmt.Errorf("unable to verify certificate request signature: %v", err)
}
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return nil, fmt.Errorf("unable to generate a serial number for %s: %v", cr.Subject.CommonName, err)
}
tmpl := &x509.Certificate{
SerialNumber: serialNumber,
Subject: cr.Subject,
DNSNames: cr.DNSNames,
IPAddresses: cr.IPAddresses,
EmailAddresses: cr.EmailAddresses,
URIs: cr.URIs,
PublicKeyAlgorithm: cr.PublicKeyAlgorithm,
PublicKey: cr.PublicKey,
Extensions: cr.Extensions,
ExtraExtensions: cr.ExtraExtensions,
}
if err := policy.apply(tmpl, ca.Certificate.NotAfter); err != nil {
return nil, err
}
der, err := x509.CreateCertificate(rand.Reader, tmpl, ca.Certificate, cr.PublicKey, ca.PrivateKey)
if err != nil {
return nil, fmt.Errorf("failed to sign certificate: %v", err)
}
return der, nil
}