mirror of
https://github.com/danderson/netboot.git
synced 2025-08-07 15:17:15 +02:00
67 lines
2.0 KiB
Go
67 lines
2.0 KiB
Go
// Copyright 2016 Google Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package pixiecore
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"encoding/base64"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
|
|
"golang.org/x/crypto/nacl/secretbox"
|
|
)
|
|
|
|
// signURL constructs an ID from u, signed with key.
|
|
func signURL(u string, key *[32]byte) (ID, error) {
|
|
var nonce [24]byte
|
|
if _, err := io.ReadFull(rand.Reader, nonce[:]); err != nil {
|
|
return "", fmt.Errorf("could not read randomness for signing nonce: %s", err)
|
|
}
|
|
|
|
out := nonce[:]
|
|
|
|
// Secretbox is authenticated encryption. In theory we only need
|
|
// symmetric authentication, but secretbox is stupidly simple to
|
|
// use and hard to get wrong, and the encryption overhead should
|
|
// be tiny for such a small URL unless you're trying to
|
|
// simultaneously netboot a million machines. This is one case
|
|
// where convenience and certainty that you got it right trumps
|
|
// pure efficiency.
|
|
out = secretbox.Seal(out, []byte(u), &nonce, key)
|
|
return ID(base64.URLEncoding.EncodeToString(out)), nil
|
|
}
|
|
|
|
// getURL returns the URL contained within id.
|
|
//
|
|
// id must have been created by signURL, with key.
|
|
func getURL(id ID, key *[32]byte) (string, error) {
|
|
signed, err := base64.URLEncoding.DecodeString(string(id))
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
if len(signed) < 24 {
|
|
return "", errors.New("signed blob too short to be valid")
|
|
}
|
|
|
|
var nonce [24]byte
|
|
copy(nonce[:], signed)
|
|
out, ok := secretbox.Open(nil, signed[24:], &nonce, key)
|
|
if !ok {
|
|
return "", errors.New("signature verification failed")
|
|
}
|
|
return string(out), nil
|
|
}
|