cert-manager/pkg/issuer/ca/issue.go
2017-09-11 10:47:58 +01:00

115 lines
3.4 KiB
Go

package ca
import (
"bytes"
"crypto/rand"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
"math/big"
"time"
"github.com/jetstack-experimental/cert-manager/pkg/apis/certmanager/v1alpha1"
"github.com/jetstack-experimental/cert-manager/pkg/util/kube"
"github.com/jetstack-experimental/cert-manager/pkg/util/pki"
k8sErrors "k8s.io/apimachinery/pkg/api/errors"
)
const (
// certificateDuration of 1 year
certificateDuration = time.Hour * 24 * 365
defaultOrganization = "cert-manager"
)
func (c *CA) Issue(crt *v1alpha1.Certificate) ([]byte, []byte, error) {
signerCert, err := kube.SecretTLSCert(c.secretsLister, c.issuer.Namespace, c.issuer.Spec.CA.SecretRef.Name)
if err != nil {
return nil, nil, err
}
signerKey, err := kube.SecretTLSKey(c.secretsLister, c.issuer.Namespace, c.issuer.Spec.CA.SecretRef.Name)
if err != nil {
return nil, nil, err
}
signeeKey, err := kube.SecretTLSKey(c.secretsLister, c.issuer.Namespace, crt.Spec.SecretName)
if k8sErrors.IsNotFound(err) {
signeeKey, err = pki.GenerateRSAPrivateKey(2048)
if err != nil {
return nil, nil, fmt.Errorf("error generating private key: %s", err.Error())
}
}
if signeeKey == nil {
return nil, nil, fmt.Errorf("error getting certificate private key: %s", err.Error())
}
crtPem, _, err := signCertificate(crt, signerCert, &signeeKey.PublicKey, signerKey)
if err != nil {
return nil, nil, err
}
return pki.EncodePKCS1PrivateKey(signeeKey), crtPem, nil
}
func createCertificateTemplate(crt *v1alpha1.Certificate, publicKey interface{}) (*x509.Certificate, error) {
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return nil, fmt.Errorf("failed to generate serial number: %s", err.Error())
}
cert := &x509.Certificate{
Version: 3,
BasicConstraintsValid: true,
SerialNumber: serialNumber,
SignatureAlgorithm: x509.SHA256WithRSA,
PublicKey: publicKey,
Subject: pkix.Name{
Organization: []string{defaultOrganization},
CommonName: crt.Spec.Domains[0],
},
NotBefore: time.Now(),
NotAfter: time.Now().Add(certificateDuration),
// see http://golang.org/pkg/crypto/x509/#KeyUsage
KeyUsage: x509.KeyUsageDigitalSignature,
DNSNames: crt.Spec.Domains,
}
return cert, nil
}
// signCertificate returns a signed x509.Certificate object for the given
// *v1alpha1.Certificate crt.
// publicKey is the public key of the signee, and signerKey is the private
// key of the signer.
func signCertificate(crt *v1alpha1.Certificate, issuerCert *x509.Certificate, publicKey interface{}, signerKey interface{}) ([]byte, *x509.Certificate, error) {
template, err := createCertificateTemplate(crt, publicKey)
if err != nil {
return nil, nil, fmt.Errorf("Error creating x509 certificate template: %s", err.Error())
}
derBytes, err := x509.CreateCertificate(rand.Reader, template, issuerCert, publicKey, signerKey)
if err != nil {
return nil, nil, fmt.Errorf("Error creating x509 certificate: %s", err.Error())
}
cert, err := pki.DecodeDERCertificateBytes(derBytes)
if err != nil {
return nil, nil, fmt.Errorf("Error decoding DER certificate bytes: %s", err.Error())
}
pemBytes := bytes.NewBuffer([]byte{})
err = pem.Encode(pemBytes, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
if err != nil {
return nil, nil, fmt.Errorf("Error encoding certificate PEM: %s", err.Error())
}
return pemBytes.Bytes(), cert, err
}