forked from canonical/lxd
/
cert.go
187 lines (159 loc) · 3.96 KB
/
cert.go
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// http://golang.org/src/pkg/crypto/tls/generate_cert.go
// 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.
package shared
import (
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
"io/ioutil"
"log"
"math/big"
"net"
"os"
"os/user"
"path"
"time"
)
// CertInfo is the representation of a Certificate in the API.
type CertInfo struct {
Certificate string `json:"certificate"`
Fingerprint string `json:"fingerprint"`
Type string `json:"type"`
}
/*
* Generate a list of names for which the certificate will be valid.
* This will include the hostname and ip address
*/
func mynames() ([]string, error) {
h, err := os.Hostname()
if err != nil {
return nil, err
}
ret := []string{h}
ifs, err := net.Interfaces()
if err != nil {
return nil, err
}
for _, iface := range ifs {
if IsLoopback(&iface) {
continue
}
addrs, err := iface.Addrs()
if err != nil {
return nil, err
}
for _, addr := range addrs {
ret = append(ret, addr.String())
}
}
return ret, nil
}
func FindOrGenCert(certf string, keyf string) error {
if PathExists(certf) && PathExists(keyf) {
return nil
}
/* If neither stat succeeded, then this is our first run and we
* need to generate cert and privkey */
err := GenCert(certf, keyf)
if err != nil {
return err
}
return nil
}
func GenCert(certf string, keyf string) error {
privk, err := rsa.GenerateKey(rand.Reader, 4096)
if err != nil {
log.Fatalf("failed to generate key")
return err
}
/* Create the basenames if needed */
dir := path.Dir(certf)
err = os.MkdirAll(dir, 0750)
if err != nil {
return err
}
dir = path.Dir(keyf)
err = os.MkdirAll(dir, 0750)
if err != nil {
return err
}
hosts, err := mynames()
if err != nil {
log.Fatalf("Failed to get my hostname")
return err
}
validFrom := time.Now()
validTo := validFrom.Add(10 * 365 * 24 * time.Hour)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
log.Fatalf("failed to generate serial number: %s", err)
return err
}
userEntry, err := user.Current()
var username string
if err == nil {
username = userEntry.Username
if username == "" {
username = "UNKNOWN"
}
} else {
username = "UNKNOWN"
}
hostname, err := os.Hostname()
if err != nil {
hostname = "UNKNOWN"
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"linuxcontainers.org"},
CommonName: fmt.Sprintf("%s@%s", username, hostname),
},
NotBefore: validFrom,
NotAfter: validTo,
KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
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, &privk.PublicKey, privk)
if err != nil {
log.Fatalf("Failed to create certificate: %s", err)
return err
}
certOut, err := os.Create(certf)
if err != nil {
log.Fatalf("failed to open %s for writing: %s", certf, err)
return err
}
pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
certOut.Close()
keyOut, err := os.OpenFile(keyf, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
log.Printf("failed to open %s for writing: %s", keyf, err)
return err
}
pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(privk)})
keyOut.Close()
return nil
}
func ReadCert(fpath string) (*x509.Certificate, error) {
cf, err := ioutil.ReadFile(fpath)
if err != nil {
return nil, err
}
certBlock, _ := pem.Decode(cf)
return x509.ParseCertificate(certBlock.Bytes)
}