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frp/utils/crypto/encode.go

90 lines
1.9 KiB

// Copyright 2017 fatedier, fatedier@gmail.com
//
// 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 crypto
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"crypto/sha1"
"io"
"golang.org/x/crypto/pbkdf2"
)
const (
salt = "frp"
)
// NewWriter returns a new Writer that encrypts bytes to w.
func NewWriter(w io.Writer, key []byte) (*Writer, error) {
key = pbkdf2.Key(key, []byte(salt), 64, aes.BlockSize, sha1.New)
// random iv
iv := make([]byte, aes.BlockSize)
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
return nil, err
}
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
return &Writer{
w: w,
enc: &cipher.StreamWriter{
S: cipher.NewCFBEncrypter(block, iv),
W: w,
},
key: key,
iv: iv,
}, nil
}
// Writer is an io.Writer that can write encrypted bytes.
// Now it only support aes-128-cfb.
type Writer struct {
w io.Writer
enc *cipher.StreamWriter
key []byte
iv []byte
ivSend bool
err error
}
// Write satisfies the io.Writer interface.
func (w *Writer) Write(p []byte) (nRet int, errRet error) {
if w.err != nil {
return 0, w.err
}
// When write is first called, iv will be written to w.w
if !w.ivSend {
w.ivSend = true
_, errRet = w.w.Write(w.iv)
if errRet != nil {
w.err = errRet
return
}
}
nRet, errRet = w.enc.Write(p)
if errRet != nil {
w.err = errRet
}
return
}