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105 lines
2.4 KiB
Go
105 lines
2.4 KiB
Go
// Copyright (c) 2021 Tulir Asokan
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package socket
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import (
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"context"
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"crypto/cipher"
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"encoding/binary"
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"sync"
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"sync/atomic"
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"github.com/gorilla/websocket"
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)
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type NoiseSocket struct {
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fs *FrameSocket
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onFrame FrameHandler
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writeKey cipher.AEAD
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readKey cipher.AEAD
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writeCounter uint32
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readCounter uint32
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writeLock sync.Mutex
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destroyed uint32
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stopConsumer chan struct{}
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}
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type DisconnectHandler func(socket *NoiseSocket, remote bool)
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type FrameHandler func([]byte)
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func newNoiseSocket(fs *FrameSocket, writeKey, readKey cipher.AEAD, frameHandler FrameHandler, disconnectHandler DisconnectHandler) (*NoiseSocket, error) {
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ns := &NoiseSocket{
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fs: fs,
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writeKey: writeKey,
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readKey: readKey,
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onFrame: frameHandler,
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stopConsumer: make(chan struct{}),
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}
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fs.OnDisconnect = func(remote bool) {
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disconnectHandler(ns, remote)
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}
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go ns.consumeFrames(fs.ctx, fs.Frames)
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return ns, nil
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}
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func (ns *NoiseSocket) consumeFrames(ctx context.Context, frames <-chan []byte) {
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ctxDone := ctx.Done()
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for {
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select {
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case frame := <-frames:
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ns.receiveEncryptedFrame(frame)
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case <-ctxDone:
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return
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case <-ns.stopConsumer:
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return
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}
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}
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}
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func generateIV(count uint32) []byte {
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iv := make([]byte, 12)
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binary.BigEndian.PutUint32(iv[8:], count)
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return iv
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}
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func (ns *NoiseSocket) Context() context.Context {
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return ns.fs.Context()
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}
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func (ns *NoiseSocket) Stop(disconnect bool) {
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if atomic.CompareAndSwapUint32(&ns.destroyed, 0, 1) {
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close(ns.stopConsumer)
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ns.fs.OnDisconnect = nil
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if disconnect {
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ns.fs.Close(websocket.CloseNormalClosure)
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}
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}
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}
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func (ns *NoiseSocket) SendFrame(plaintext []byte) error {
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ns.writeLock.Lock()
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ciphertext := ns.writeKey.Seal(nil, generateIV(ns.writeCounter), plaintext, nil)
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ns.writeCounter++
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err := ns.fs.SendFrame(ciphertext)
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ns.writeLock.Unlock()
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return err
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}
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func (ns *NoiseSocket) receiveEncryptedFrame(ciphertext []byte) {
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count := atomic.AddUint32(&ns.readCounter, 1) - 1
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plaintext, err := ns.readKey.Open(nil, generateIV(count), ciphertext, nil)
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if err != nil {
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ns.fs.log.Warnf("Failed to decrypt frame: %v", err)
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return
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}
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ns.onFrame(plaintext)
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}
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func (ns *NoiseSocket) IsConnected() bool {
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return ns.fs.IsConnected()
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}
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