frp/utils/crypto/decode.go

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// 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/sha1"
"io"
"golang.org/x/crypto/pbkdf2"
)
// NewReader returns a new Reader that decrypts bytes from r
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func NewReader(r io.Reader, key []byte) *Reader {
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key = pbkdf2.Key(key, []byte(salt), 64, aes.BlockSize, sha1.New)
return &Reader{
r: r,
key: key,
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}
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}
// Reader is an io.Reader that can read encrypted bytes.
// Now it only supports aes-128-cfb.
type Reader struct {
r io.Reader
dec *cipher.StreamReader
key []byte
iv []byte
err error
}
// Read satisfies the io.Reader interface.
func (r *Reader) Read(p []byte) (nRet int, errRet error) {
if r.err != nil {
return 0, r.err
}
if r.dec == nil {
iv := make([]byte, aes.BlockSize)
if _, errRet = io.ReadFull(r.r, iv); errRet != nil {
return
}
r.iv = iv
block, err := aes.NewCipher(r.key)
if err != nil {
errRet = err
return
}
r.dec = &cipher.StreamReader{
S: cipher.NewCFBDecrypter(block, iv),
R: r.r,
}
}
nRet, errRet = r.dec.Read(p)
if errRet != nil {
r.err = errRet
}
return
}