mirror of https://github.com/fatedier/frp.git
90 lines
1.9 KiB
Go
90 lines
1.9 KiB
Go
// Copyright 2017 fatedier, fatedier@gmail.com
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package crypto
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha1"
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"io"
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"golang.org/x/crypto/pbkdf2"
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)
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const (
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salt = "frp"
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)
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// NewWriter returns a new Writer that encrypts bytes to w.
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func NewWriter(w io.Writer, key []byte) (*Writer, error) {
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key = pbkdf2.Key(key, []byte(salt), 64, aes.BlockSize, sha1.New)
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// random iv
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iv := make([]byte, aes.BlockSize)
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if _, err := io.ReadFull(rand.Reader, iv); err != nil {
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return nil, err
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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return &Writer{
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w: w,
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enc: &cipher.StreamWriter{
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S: cipher.NewCFBEncrypter(block, iv),
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W: w,
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},
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key: key,
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iv: iv,
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}, nil
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}
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// Writer is an io.Writer that can write encrypted bytes.
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// Now it only support aes-128-cfb.
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type Writer struct {
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w io.Writer
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enc *cipher.StreamWriter
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key []byte
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iv []byte
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ivSend bool
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err error
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}
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// Write satisfies the io.Writer interface.
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func (w *Writer) Write(p []byte) (nRet int, errRet error) {
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if w.err != nil {
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return 0, w.err
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}
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// When write is first called, iv will be written to w.w
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if !w.ivSend {
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w.ivSend = true
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_, errRet = w.w.Write(w.iv)
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if errRet != nil {
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w.err = errRet
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return
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}
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}
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nRet, errRet = w.enc.Write(p)
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if errRet != nil {
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w.err = errRet
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}
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return
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}
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