/
certificate.go
133 lines (115 loc) · 2.93 KB
/
certificate.go
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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Generate a self-signed X.509 certificate for a TLS server. Outputs to
// 'cert.pem' and 'key.pem' and will overwrite existing files.
// Small modifications by kabukky and bobheadxi
package crypto
import (
"crypto/ecdsa"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"errors"
"math/big"
"net"
"os"
"strings"
"time"
)
var (
validFor = 365 * 24 * time.Hour
isCA = true
rsaBits = 2048
)
func publicKey(priv interface{}) interface{} {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &k.PublicKey
case *ecdsa.PrivateKey:
return &k.PublicKey
default:
return nil
}
}
func pemBlockForKey(priv interface{}) (*pem.Block, error) {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(k)}, nil
case *ecdsa.PrivateKey:
b, err := x509.MarshalECPrivateKey(k)
if err != nil {
return nil, err
}
return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}, nil
default:
return nil, nil
}
}
// GenerateCertificate creates an SSL certificate for HTTPS use
func GenerateCertificate(certPath, keyPath, host, method string) error {
var priv interface{}
var err error
switch method {
case "RSA":
priv, err = rsa.GenerateKey(rand.Reader, rsaBits)
default:
return errors.New("Unrecognised algorithm " + method)
}
if err != nil {
return err
}
notBefore := time.Now()
notAfter := notBefore.Add(validFor)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return err
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"UBC Launch Pad"},
},
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
hosts := strings.Split(host, ",")
for _, h := range hosts {
if ip := net.ParseIP(h); ip != nil {
template.IPAddresses = append(template.IPAddresses, ip)
} else {
template.DNSNames = append(template.DNSNames, h)
}
}
if isCA {
template.IsCA = true
template.KeyUsage |= x509.KeyUsageCertSign
}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
if err != nil {
return err
}
certOut, err := os.Create(certPath)
if err != nil {
return err
}
defer certOut.Close()
pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return err
}
defer keyOut.Close()
block, err := pemBlockForKey(priv)
if err != nil {
return err
}
pem.Encode(keyOut, block)
return nil
}