Add ability to autogen self-signed x509 certs for use with Grumble.

gencert.go

@@ -0,0 +1,79 @@
+// Copyright (c) 2011 The Grumble Authors
+// The use of this source code is goverened by a BSD-style
+// license that can be found in the LICENSE-file.
+
+package main
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// Generate a 2048-bit RSA keypair and a Grumble auto-generated X509
+// certificate. Output PEM-encoded DER representations of the resulting
+// certificate and private key to certpath and keypath.
+func GenerateSelfSignedCert(certpath, keypath string) (err os.Error) {
+	now := time.Seconds()
+	tmpl := &x509.Certificate{
+		SerialNumber: []byte{0},
+		Subject: x509.Name{
+			CommonName: "Grumble Autogenerated Certificate",
+		},
+		NotBefore: time.SecondsToUTC(now - 300),
+		NotAfter:  time.SecondsToUTC(now + 60*60*24*365), // valid for 1 year.
+
+		SubjectKeyId: []byte{1, 2, 3, 4},
+		KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+	}
+
+	priv, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return err
+	}
+
+	certbuf, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, &priv.PublicKey, priv)
+	if err != nil {
+		log.Printf("Error: %v", err)
+		return err
+	}
+	certblk := pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certbuf,
+	}
+
+	keybuf := x509.MarshalPKCS1PrivateKey(priv)
+	keyblk := pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: keybuf,
+	}
+
+	certfn := filepath.Join(*datadir, "cert")
+	file, err := os.OpenFile(certfn, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0700)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	err = pem.Encode(file, &certblk)
+	if err != nil {
+		return err
+	}
+
+	keyfn := filepath.Join(*datadir, "key")
+	file, err = os.OpenFile(keyfn, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0700)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	err = pem.Encode(file, &keyblk)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}