examples: tls: Add a simple TLS example
Was useful for testing things...
This commit is contained in:
James Shubin
203
examples/tls/tls.go
Normal file
203
examples/tls/tls.go
Normal file
@@ -0,0 +1,203 @@
|
||||
// Modified from: golang/src/crypto/tls/generate_cert.go
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"crypto/ecdsa"
|
||||
"crypto/ed25519"
|
||||
"crypto/elliptic"
|
||||
"crypto/rand"
|
||||
"crypto/rsa"
|
||||
"crypto/x509"
|
||||
"crypto/x509/pkix"
|
||||
"encoding/pem"
|
||||
"fmt"
|
||||
"log"
|
||||
"math/big"
|
||||
"net"
|
||||
"net/http"
|
||||
"os"
|
||||
"strings"
|
||||
"time"
|
||||
)
|
||||
|
||||
// NewTLS builds a new TLS struct with some defaults.
|
||||
func NewTLS() *TLS {
|
||||
return &TLS{
|
||||
ValidFor: 365 * 24 * time.Hour,
|
||||
RsaBits: 2048,
|
||||
}
|
||||
}
|
||||
|
||||
// TLS handles all of the TLS building.
|
||||
type TLS struct {
|
||||
Host string // Comma-separated hostnames and IPs to generate a certificate for
|
||||
ValidFrom string // Creation date formatted as Jan 1 15:04:05 2011
|
||||
ValidFor time.Duration // Duration that certificate is valid for
|
||||
IsCA bool // Whether this cert should be its own Certificate Authority
|
||||
RsaBits int // Size of RSA key to generate. Ignored if EcdsaCurve is set
|
||||
EcdsaCurve string // ECDSA curve to use to generate a key. Valid values are P224, P256 (recommended), P384, P521
|
||||
Ed25519Key bool // Generate an Ed25519 key
|
||||
}
|
||||
|
||||
// Generate writes out the two files. Usually keyPemFile is key.pem and
|
||||
// certPemFile is cert.pem which go into http.ListenAndServeTLS.
|
||||
func (obj *TLS) Generate(keyPemFile, certPemFile string) error {
|
||||
|
||||
if len(obj.Host) == 0 {
|
||||
return fmt.Errorf("missing required Host parameter")
|
||||
}
|
||||
|
||||
var priv any
|
||||
var err error
|
||||
switch obj.EcdsaCurve {
|
||||
case "":
|
||||
if obj.Ed25519Key {
|
||||
_, priv, err = ed25519.GenerateKey(rand.Reader)
|
||||
} else {
|
||||
priv, err = rsa.GenerateKey(rand.Reader, obj.RsaBits)
|
||||
}
|
||||
case "P224":
|
||||
priv, err = ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
|
||||
case "P256":
|
||||
priv, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
|
||||
case "P384":
|
||||
priv, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
|
||||
case "P521":
|
||||
priv, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
|
||||
default:
|
||||
return fmt.Errorf("unrecognized elliptic curve: %q", obj.EcdsaCurve)
|
||||
}
|
||||
if err != nil {
|
||||
return fmt.Errorf("failed to generate private key: %v", err)
|
||||
}
|
||||
|
||||
// ECDSA, ED25519 and RSA subject keys should have the DigitalSignature
|
||||
// KeyUsage bits set in the x509.Certificate template
|
||||
keyUsage := x509.KeyUsageDigitalSignature
|
||||
// Only RSA subject keys should have the KeyEncipherment KeyUsage bits set. In
|
||||
// the context of TLS this KeyUsage is particular to RSA key exchange and
|
||||
// authentication.
|
||||
if _, isRSA := priv.(*rsa.PrivateKey); isRSA {
|
||||
keyUsage |= x509.KeyUsageKeyEncipherment
|
||||
}
|
||||
|
||||
var notBefore time.Time
|
||||
if len(obj.ValidFrom) == 0 {
|
||||
notBefore = time.Now()
|
||||
} else {
|
||||
notBefore, err = time.Parse("Jan 2 15:04:05 2006", obj.ValidFrom)
|
||||
if err != nil {
|
||||
return fmt.Errorf("failed to parse creation date: %v", err)
|
||||
}
|
||||
}
|
||||
|
||||
notAfter := notBefore.Add(obj.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: %v", err)
|
||||
}
|
||||
|
||||
template := x509.Certificate{
|
||||
SerialNumber: serialNumber,
|
||||
Subject: pkix.Name{
|
||||
Organization: []string{"Whatever Corp"}, // XXX: change me...
|
||||
},
|
||||
NotBefore: notBefore,
|
||||
NotAfter: notAfter,
|
||||
|
||||
KeyUsage: keyUsage,
|
||||
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
|
||||
BasicConstraintsValid: true,
|
||||
}
|
||||
|
||||
hosts := strings.Split(obj.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 obj.IsCA {
|
||||
template.IsCA = true
|
||||
template.KeyUsage |= x509.KeyUsageCertSign
|
||||
}
|
||||
|
||||
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
|
||||
if err != nil {
|
||||
return fmt.Errorf("failed to create certificate: %v", err)
|
||||
}
|
||||
|
||||
certOut, err := os.Create(certPemFile)
|
||||
if err != nil {
|
||||
return fmt.Errorf("failed to open %s for writing: %v", certPemFile, err)
|
||||
}
|
||||
if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
|
||||
return fmt.Errorf("failed to write data to %s: %v", certPemFile, err)
|
||||
}
|
||||
if err := certOut.Close(); err != nil {
|
||||
return fmt.Errorf("error closing %s: %v", certPemFile, err)
|
||||
}
|
||||
log.Printf("wrote %s", certPemFile)
|
||||
|
||||
keyOut, err := os.OpenFile(keyPemFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
|
||||
if err != nil {
|
||||
return fmt.Errorf("failed to open %s for writing: %v", keyPemFile, err)
|
||||
}
|
||||
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
|
||||
if err != nil {
|
||||
return fmt.Errorf("unable to marshal private key: %v", err)
|
||||
}
|
||||
if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
|
||||
return fmt.Errorf("failed to write data to %s: %v", keyPemFile, err)
|
||||
}
|
||||
if err := keyOut.Close(); err != nil {
|
||||
return fmt.Errorf("error closing %s: %v", keyPemFile, err)
|
||||
}
|
||||
log.Printf("wrote %s", keyPemFile)
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// HelloServer is a simple handler.
|
||||
func HelloServer(w http.ResponseWriter, req *http.Request) {
|
||||
fmt.Printf("req: %+v\n", req)
|
||||
w.Header().Set("Content-Type", "text/plain")
|
||||
w.Write([]byte("This is hello world!\n"))
|
||||
}
|
||||
|
||||
func publicKey(priv any) any {
|
||||
switch k := priv.(type) {
|
||||
case *rsa.PrivateKey:
|
||||
return &k.PublicKey
|
||||
case *ecdsa.PrivateKey:
|
||||
return &k.PublicKey
|
||||
case ed25519.PrivateKey:
|
||||
return k.Public().(ed25519.PublicKey)
|
||||
default:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
func main() {
|
||||
// wget --no-check-certificate https://127.0.0.1:1443/hello -O -
|
||||
|
||||
tls := NewTLS()
|
||||
tls.Host = "localhost" // TODO: choose something
|
||||
keyPemFile := "/tmp/key.pem"
|
||||
certPemFile := "/tmp/cert.pem"
|
||||
|
||||
if err := tls.Generate(keyPemFile, certPemFile); err != nil {
|
||||
fmt.Printf("error: %v\n", err)
|
||||
return
|
||||
}
|
||||
|
||||
http.HandleFunc("/hello", HelloServer)
|
||||
if err := http.ListenAndServeTLS(":1443", certPemFile, keyPemFile, nil); err != nil {
|
||||
log.Fatal("ListenAndServe: ", err)
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user