141 lines
3.7 KiB
Go
141 lines
3.7 KiB
Go
package utils
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"crypto/rsa"
|
|
"crypto/x509"
|
|
"crypto/x509/pkix"
|
|
"encoding/pem"
|
|
"log"
|
|
"math/big"
|
|
"net"
|
|
"os"
|
|
"path/filepath"
|
|
"time"
|
|
)
|
|
|
|
func GenerateCerts(tlsCert string, tlsKey string) {
|
|
// @see https://shaneutt.com/blog/golang-ca-and-signed-cert-go/
|
|
// @see https://golang.org/src/crypto/tls/generate_cert.go
|
|
validFrom := ""
|
|
validFor := 365 * 24 * time.Hour
|
|
isCA := true
|
|
|
|
// Get the hostname
|
|
hostname, err := os.Hostname()
|
|
if err != nil {
|
|
log.Printf("failed to lookup hostname: '%s'\n", err)
|
|
hostname = "localhost"
|
|
}
|
|
|
|
// Check that the directory exists
|
|
relativePath := filepath.Dir(tlsCert)
|
|
log.Printf("GenerateCerts relative path for file creation is '%s'\n", relativePath)
|
|
_, err = os.Stat(relativePath)
|
|
if os.IsNotExist(err) {
|
|
log.Printf("Certificate path does not exist, creating %s before generating certificate\n", relativePath)
|
|
os.MkdirAll(relativePath, os.ModePerm)
|
|
}
|
|
|
|
// Generate a private key
|
|
priv, err := rsa.GenerateKey(rand.Reader, rsaBits)
|
|
if err != nil {
|
|
log.Fatalf("Failed to generate private key: %v", err)
|
|
}
|
|
|
|
var notBefore time.Time
|
|
if len(validFrom) == 0 {
|
|
notBefore = time.Now()
|
|
} else {
|
|
notBefore, err = time.Parse("Jan 2 15:04:05 2006", validFrom)
|
|
if err != nil {
|
|
log.Fatalf("Failed to parse creation date: %v", err)
|
|
}
|
|
}
|
|
|
|
notAfter := notBefore.Add(validFor)
|
|
|
|
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: %v", err)
|
|
}
|
|
|
|
template := x509.Certificate{
|
|
SerialNumber: serialNumber,
|
|
Subject: pkix.Name{
|
|
Organization: []string{"DTMS"},
|
|
},
|
|
NotBefore: notBefore,
|
|
NotAfter: notAfter,
|
|
|
|
KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
|
|
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
|
|
BasicConstraintsValid: true,
|
|
}
|
|
|
|
template.DNSNames = append(template.DNSNames, hostname)
|
|
|
|
// Add in all the non-local IPs
|
|
ifaces, err := net.Interfaces()
|
|
|
|
if err != nil {
|
|
log.Printf("Error enumerating interfaces: %v\n", err)
|
|
}
|
|
|
|
for _, i := range ifaces {
|
|
addrs, err := i.Addrs()
|
|
if err != nil {
|
|
log.Printf("Oops: %v\n", err)
|
|
}
|
|
|
|
for _, address := range addrs {
|
|
// check the address type and if it is not a loopback then add it to the list
|
|
if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
|
|
if ipnet.IP.To4() != nil {
|
|
template.IPAddresses = append(template.IPAddresses, ipnet.IP)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if isCA {
|
|
template.IsCA = true
|
|
template.KeyUsage |= x509.KeyUsageCertSign
|
|
}
|
|
|
|
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
|
|
if err != nil {
|
|
log.Fatalf("Failed to create certificate: %v", err)
|
|
}
|
|
|
|
certOut, err := os.Create(tlsCert)
|
|
if err != nil {
|
|
log.Fatalf("Failed to open %s for writing: %v", tlsCert, err)
|
|
}
|
|
if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
|
|
log.Fatalf("Failed to write data to %s: %v", tlsCert, err)
|
|
}
|
|
if err := certOut.Close(); err != nil {
|
|
log.Fatalf("Error closing %s: %v", tlsCert, err)
|
|
}
|
|
log.Printf("wrote %s\n", tlsCert)
|
|
|
|
keyOut, err := os.OpenFile(tlsKey, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
|
|
if err != nil {
|
|
log.Fatalf("Failed to open %s for writing: %v", tlsKey, err)
|
|
return
|
|
}
|
|
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
|
|
if err != nil {
|
|
log.Fatalf("Unable to marshal private key: %v", err)
|
|
}
|
|
if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
|
|
log.Fatalf("Failed to write data to %s: %v", tlsKey, err)
|
|
}
|
|
if err := keyOut.Close(); err != nil {
|
|
log.Fatalf("Error closing %s: %v", tlsKey, err)
|
|
}
|
|
log.Printf("wrote %s\n", tlsKey)
|
|
}
|