Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
257 lines (212 sloc) 6.57 KB
package certcrypto
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/pem"
"errors"
"fmt"
"math/big"
"time"
"golang.org/x/crypto/ocsp"
)
// Constants for all key types we support.
const (
EC256 = KeyType("P256")
EC384 = KeyType("P384")
RSA2048 = KeyType("2048")
RSA4096 = KeyType("4096")
RSA8192 = KeyType("8192")
)
const (
// OCSPGood means that the certificate is valid.
OCSPGood = ocsp.Good
// OCSPRevoked means that the certificate has been deliberately revoked.
OCSPRevoked = ocsp.Revoked
// OCSPUnknown means that the OCSP responder doesn't know about the certificate.
OCSPUnknown = ocsp.Unknown
// OCSPServerFailed means that the OCSP responder failed to process the request.
OCSPServerFailed = ocsp.ServerFailed
)
// Constants for OCSP must staple
var (
tlsFeatureExtensionOID = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 24}
ocspMustStapleFeature = []byte{0x30, 0x03, 0x02, 0x01, 0x05}
)
// KeyType represents the key algo as well as the key size or curve to use.
type KeyType string
type DERCertificateBytes []byte
// ParsePEMBundle parses a certificate bundle from top to bottom and returns
// a slice of x509 certificates. This function will error if no certificates are found.
func ParsePEMBundle(bundle []byte) ([]*x509.Certificate, error) {
var certificates []*x509.Certificate
var certDERBlock *pem.Block
for {
certDERBlock, bundle = pem.Decode(bundle)
if certDERBlock == nil {
break
}
if certDERBlock.Type == "CERTIFICATE" {
cert, err := x509.ParseCertificate(certDERBlock.Bytes)
if err != nil {
return nil, err
}
certificates = append(certificates, cert)
}
}
if len(certificates) == 0 {
return nil, errors.New("no certificates were found while parsing the bundle")
}
return certificates, nil
}
func ParsePEMPrivateKey(key []byte) (crypto.PrivateKey, error) {
keyBlock, _ := pem.Decode(key)
switch keyBlock.Type {
case "RSA PRIVATE KEY":
return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
case "EC PRIVATE KEY":
return x509.ParseECPrivateKey(keyBlock.Bytes)
default:
return nil, errors.New("unknown PEM header value")
}
}
func GeneratePrivateKey(keyType KeyType) (crypto.PrivateKey, error) {
switch keyType {
case EC256:
return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
case EC384:
return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
case RSA2048:
return rsa.GenerateKey(rand.Reader, 2048)
case RSA4096:
return rsa.GenerateKey(rand.Reader, 4096)
case RSA8192:
return rsa.GenerateKey(rand.Reader, 8192)
}
return nil, fmt.Errorf("invalid KeyType: %s", keyType)
}
func GenerateCSR(privateKey crypto.PrivateKey, domain string, san []string, mustStaple bool) ([]byte, error) {
template := x509.CertificateRequest{
Subject: pkix.Name{CommonName: domain},
DNSNames: san,
}
if mustStaple {
template.ExtraExtensions = append(template.ExtraExtensions, pkix.Extension{
Id: tlsFeatureExtensionOID,
Value: ocspMustStapleFeature,
})
}
return x509.CreateCertificateRequest(rand.Reader, &template, privateKey)
}
func PEMEncode(data interface{}) []byte {
return pem.EncodeToMemory(PEMBlock(data))
}
func PEMBlock(data interface{}) *pem.Block {
var pemBlock *pem.Block
switch key := data.(type) {
case *ecdsa.PrivateKey:
keyBytes, _ := x509.MarshalECPrivateKey(key)
pemBlock = &pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
case *rsa.PrivateKey:
pemBlock = &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
case *x509.CertificateRequest:
pemBlock = &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: key.Raw}
case DERCertificateBytes:
pemBlock = &pem.Block{Type: "CERTIFICATE", Bytes: []byte(data.(DERCertificateBytes))}
}
return pemBlock
}
func pemDecode(data []byte) (*pem.Block, error) {
pemBlock, _ := pem.Decode(data)
if pemBlock == nil {
return nil, fmt.Errorf("PEM decode did not yield a valid block. Is the certificate in the right format?")
}
return pemBlock, nil
}
func PemDecodeTox509CSR(pem []byte) (*x509.CertificateRequest, error) {
pemBlock, err := pemDecode(pem)
if pemBlock == nil {
return nil, err
}
if pemBlock.Type != "CERTIFICATE REQUEST" {
return nil, fmt.Errorf("PEM block is not a certificate request")
}
return x509.ParseCertificateRequest(pemBlock.Bytes)
}
// ParsePEMCertificate returns Certificate from a PEM encoded certificate.
// The certificate has to be PEM encoded. Any other encodings like DER will fail.
func ParsePEMCertificate(cert []byte) (*x509.Certificate, error) {
pemBlock, err := pemDecode(cert)
if pemBlock == nil {
return nil, err
}
// from a DER encoded certificate
return x509.ParseCertificate(pemBlock.Bytes)
}
func ExtractDomains(cert *x509.Certificate) []string {
domains := []string{cert.Subject.CommonName}
// Check for SAN certificate
for _, sanDomain := range cert.DNSNames {
if sanDomain == cert.Subject.CommonName {
continue
}
domains = append(domains, sanDomain)
}
return domains
}
func ExtractDomainsCSR(csr *x509.CertificateRequest) []string {
domains := []string{csr.Subject.CommonName}
// loop over the SubjectAltName DNS names
for _, sanName := range csr.DNSNames {
if containsSAN(domains, sanName) {
// Duplicate; skip this name
continue
}
// Name is unique
domains = append(domains, sanName)
}
return domains
}
func containsSAN(domains []string, sanName string) bool {
for _, existingName := range domains {
if existingName == sanName {
return true
}
}
return false
}
func GeneratePemCert(privateKey *rsa.PrivateKey, domain string, extensions []pkix.Extension) ([]byte, error) {
derBytes, err := generateDerCert(privateKey, time.Time{}, domain, extensions)
if err != nil {
return nil, err
}
return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes}), nil
}
func generateDerCert(privateKey *rsa.PrivateKey, expiration time.Time, domain string, extensions []pkix.Extension) ([]byte, error) {
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return nil, err
}
if expiration.IsZero() {
expiration = time.Now().Add(365)
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
CommonName: "ACME Challenge TEMP",
},
NotBefore: time.Now(),
NotAfter: expiration,
KeyUsage: x509.KeyUsageKeyEncipherment,
BasicConstraintsValid: true,
DNSNames: []string{domain},
ExtraExtensions: extensions,
}
return x509.CreateCertificate(rand.Reader, &template, &template, &privateKey.PublicKey, privateKey)
}
You can’t perform that action at this time.