forked from janimo/imageserver
/
generate_keys.go
253 lines (223 loc) · 5.28 KB
/
generate_keys.go
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//
// imageserver - Server for Ubuntu Touch system images
//
// Copyright (c) 2014 Canonical Ltd.
//
// Author: Jani Monoses <jani.monoses@canonical.com>
package main
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License version 3, as published
// by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranties of
// MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
// PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. If not, see <http://www.gnu.org/licenses/>.
import (
"archive/tar"
"bytes"
"encoding/json"
"io"
"io/ioutil"
"log"
"os"
"path/filepath"
"time"
"code.google.com/p/go.crypto/openpgp"
"github.com/remyoudompheng/go-liblzma"
)
type keyringJSON struct {
Expiry int64 `json:"expiry,omitempty"`
Type string `json:"type"`
}
// Key describes a key used in signing image tarballs
type Key struct {
typ string
dir string
name string
comment string
email string
signer string
expiry *time.Time
entity *openpgp.Entity
}
// signFile creates a GPG detached ASCII armored signature (.asc file) for a given file
// using the given key
func signFile(path string, ent *openpgp.Entity) {
sigpath := path + ".asc"
reader, err := os.Open(path)
if err != nil {
log.Fatal(err)
}
writer, err := os.Create(sigpath)
if err != nil {
log.Fatal(err)
}
openpgp.ArmoredDetachSign(writer, ent, reader, nil)
}
// generate creates a GPG keypair and keyring tarballs
func (k *Key) generate() error {
ent, err := openpgp.NewEntity(k.name, k.comment, k.email, nil)
if err != nil {
return err
}
//FIXME: how to not have subkeys otherwise?
ent.Subkeys = nil
k.entity = ent
os.MkdirAll(k.dir, 0700)
pubring, err := os.Create(filepath.Join(k.dir, "pubring.gpg"))
if err != nil {
return err
}
secring, err := os.Create(filepath.Join(k.dir, "secring.gpg"))
if err != nil {
return err
}
if err = ent.SerializePrivate(secring, nil); err != nil {
return err
}
if err = ent.Serialize(pubring); err != nil {
return err
}
k.writeKeyringJSON()
return nil
}
func (k *Key) writeKeyringJSON() error {
kr := &keyringJSON{Type: k.typ}
if k.expiry != nil {
kr.Expiry = k.expiry.Unix()
}
b, err := json.MarshalIndent(kr, "", " ")
if err != nil {
return err
}
err = ioutil.WriteFile(filepath.Join(k.dir, "keyring.json"), b, 0600)
if err != nil {
return err
}
return err
}
// Default expiry date for image-signing and device-signing keys
var twoYearsFromNow = time.Now().AddDate(2, 0, 0)
var signingKeys = map[string]*Key{
"archive-master": {
name: "[TESTING] Ubuntu Archive Master Signing Key",
email: "ftpmaster@ubuntu.com",
expiry: nil,
signer: "archive-master",
},
"image-master": {
name: "[TESTING] Ubuntu System Image Master Signing Key",
email: "system-image@ubuntu.com",
expiry: nil,
signer: "archive-master",
},
"image-signing": {
name: "[TESTING] Ubuntu System Image Signing Key",
comment: "YYYY",
email: "system-image@ubuntu.com",
expiry: &twoYearsFromNow,
signer: "image-master",
},
"device-signing": {
name: "[TESTING] Random OEM Signing Key",
comment: "YYYY",
email: "system-image@ubuntu.com",
expiry: &twoYearsFromNow,
signer: "image-signing",
},
}
func createGPGKeys() error {
for n, k := range signingKeys {
log.Printf("Creating %s GPG key\n", n)
k.typ = n
k.dir = filepath.Join(keysDir, n)
err := k.generate()
if err != nil {
return err
}
}
return nil
}
//tarDirectory makes a tar.xz archive from the given directory
func tarDirectory(dir, name string) error {
var buf bytes.Buffer
tw := tar.NewWriter(&buf)
defer tw.Close()
if err := addFile(filepath.Join(dir, "keyring.json"), "keyring.json", tw); err != nil {
return err
}
if err := addFile(filepath.Join(dir, "pubring.gpg"), "keyring.gpg", tw); err != nil {
return err
}
tw.Close()
tarxz, err := os.Create(name)
if err != nil {
return err
}
defer tarxz.Close()
xzw, err := xz.NewWriter(tarxz, xz.LevelDefault)
if err != nil {
return err
}
defer xzw.Close()
_, err = io.Copy(xzw, &buf)
return nil
}
//addFile adds the file named name as a tar entry named tarname
func addFile(name string, tarname string, tw *tar.Writer) error {
if tarname == "" {
tarname = name
}
fi, err := os.Stat(name)
if err != nil {
return err
}
hdr, err := tar.FileInfoHeader(fi, "")
if err != nil {
return err
}
hdr.Name = tarname
err = tw.WriteHeader(hdr)
if err != nil {
return err
}
f, err := os.Open(name)
if err != nil {
return err
}
_, err = io.Copy(tw, f)
if err != nil {
return err
}
tw.Flush()
return nil
}
func createKeyrings() error {
os.MkdirAll(gpgDir, 0700)
for d, k := range signingKeys {
p := filepath.Join(gpgDir, d) + ".tar.xz"
log.Printf("Creating %s keyring tarball\n", d)
if err := tarDirectory(k.dir, p); err != nil {
return err
}
signFile(p, signingKeys[k.signer].entity)
}
return nil
}
func generateKeys() {
if exists(gpgDir) && exists(keysDir) {
return
}
err := createGPGKeys()
if err != nil {
log.Fatal(err)
}
err = createKeyrings()
if err != nil {
log.Fatal(err)
}
}