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generate_cert_lean.go
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generate_cert_lean.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.
// THIS CODE IS JUST A LEAN VERISON OF: http://golang.org/src/crypto/tls/generate_cert.go
package main
import (
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
"math/big"
"net"
"os"
"strings"
"time"
)
var (
host = "localhost"
validFor = 365 * 24 * time.Hour
rsaBits = 2048
)
func generateCert(certFile, keyFile string) error {
if len(host) == 0 {
return fmt.Errorf("Missing required --host parameter")
}
priv, err := rsa.GenerateKey(rand.Reader, rsaBits)
if err != nil {
return fmt.Errorf("failed to generate private key: %s", err)
}
var notBefore time.Time
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 fmt.Errorf("failed to generate serial number: %s", err)
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"Acme Co"},
},
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)
}
}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
if err != nil {
return fmt.Errorf("failed to create certificate: %s", err)
}
certOut, err := os.Create(certFile)
if err != nil {
return fmt.Errorf("failed to open %s for writing: %s", certFile, err)
}
pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
certOut.Close()
keyOut, err := os.OpenFile(keyFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return fmt.Errorf("failed to open %s for writing: %s", keyFile, err)
}
pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)})
keyOut.Close()
return nil
}