336 lines
8.0 KiB
JavaScript
336 lines
8.0 KiB
JavaScript
// Sshwifty - A Web SSH client
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//
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// Copyright (C) 2019 Rui NI <nirui@gmx.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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import * as streams from "./stream/streams.js";
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import * as reader from "./stream/reader.js";
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import * as sender from "./stream/sender.js";
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import * as crypt from "./crypto.js";
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export const ECHO_FAILED = streams.ECHO_FAILED;
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class Dial {
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/**
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* constructor
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*
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* @param {string} address Address to the Websocket server
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* @param {number} Dial timeout
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* @param {object} privateKey String key that will be used to encrypt and
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* decrypt socket traffic
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*
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*/
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constructor(address, timeout, privateKey) {
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this.address = address;
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this.timeout = timeout;
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this.privateKey = privateKey;
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}
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/**
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* Connect to the remote server
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*
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* @param {number} timeout Connect timeout
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*
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* @returns {Promise<WebSocket>} When connection is established
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*
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*/
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connect(timeout) {
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return new Promise((resolve, reject) => {
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let ws = new WebSocket(this.address),
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promised = false,
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timeoutTimer = setTimeout(() => {
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ws.close();
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}, timeout),
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myRes = w => {
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if (promised) {
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return;
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}
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clearTimeout(timeoutTimer);
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promised = true;
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return resolve(w);
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},
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myRej = e => {
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if (promised) {
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return;
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}
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clearTimeout(timeoutTimer);
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promised = true;
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return reject(e);
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};
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ws.addEventListener("open", event => {
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myRes(ws);
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});
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ws.addEventListener("close", event => {
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event.toString = () => {
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return "WebSocket Error (" + event.code + ")";
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};
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myRej(event);
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});
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ws.addEventListener("error", event => {
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ws.close();
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});
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});
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}
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/**
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* Build an socket encrypt and decrypt key string
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*
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*/
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async buildKeyString() {
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const enc = new TextEncoder("utf-8");
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let rTime = Number(Math.trunc(new Date().getTime() / 100000)),
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key = await crypt.hmac512(
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enc.encode(await this.privateKey.fetch()),
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enc.encode(rTime)
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);
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return key.slice(0, 16);
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}
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/**
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* Build encrypt and decrypt key
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*
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*/
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async buildKey() {
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let kStr = await this.buildKeyString();
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return await crypt.buildGCMKey(kStr);
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}
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/**
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* Connect to the server
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*
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* @param {object} callbacks Callbacks
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*
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* @returns {object} A pair of ReadWriter which can be used to read and
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* send data to the underlaying websocket connection
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*
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*/
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async dial(callbacks) {
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let ws = await this.connect(this.timeout),
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rd = new reader.Reader(new reader.Multiple(() => {}), data => {
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return new Promise(resolve => {
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let bufferReader = new FileReader();
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bufferReader.onload = event => {
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let d = new Uint8Array(event.target.result);
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resolve(d);
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callbacks.inboundUnpacked(d);
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};
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bufferReader.readAsArrayBuffer(data);
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});
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}),
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sdDataConvert = rawData => {
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return rawData;
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},
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sd = new sender.Sender(
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async rawData => {
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let data = await sdDataConvert(rawData);
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ws.send(data.buffer);
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callbacks.outbound(data);
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},
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15,
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4096 - 64 // Server has a 4096 bytes receive buffer, can be no greater
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);
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ws.addEventListener("message", event => {
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callbacks.inbound(event.data);
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rd.feed(event.data);
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});
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ws.addEventListener("error", event => {
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rd.close();
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});
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ws.addEventListener("close", event => {
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rd.close();
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});
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let senderNonce = crypt.generateNonce();
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sd.send(senderNonce);
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let receiverNonce = await reader.readN(rd, crypt.GCMNonceSize);
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let key = await this.buildKey();
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sdDataConvert = async rawData => {
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let encoded = await crypt.encryptGCM(key, senderNonce, rawData);
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crypt.increaseNonce(senderNonce);
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let dataToSend = new Uint8Array(encoded.byteLength + 2);
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dataToSend[0] = (encoded.byteLength >> 8) & 0xff;
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dataToSend[1] = encoded.byteLength & 0xff;
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dataToSend.set(new Uint8Array(encoded), 2);
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return dataToSend;
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};
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let cgmReader = new reader.Multiple(async r => {
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try {
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let dSizeBytes = await reader.readN(rd, 2),
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dSize = 0;
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dSize = dSizeBytes[0];
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dSize <<= 8;
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dSize |= dSizeBytes[1];
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let decoded = await crypt.decryptGCM(
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key,
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receiverNonce,
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await reader.readN(rd, dSize)
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);
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crypt.increaseNonce(receiverNonce);
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r.feed(new reader.Buffer(new Uint8Array(decoded), () => {}), () => {});
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} catch (e) {
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r.close();
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}
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});
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return {
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reader: cgmReader,
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sender: sd,
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ws: ws
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};
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}
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}
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export class Socket {
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/**
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* constructor
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*
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* @param {string} address Address of the WebSocket server
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* @param {object} privateKey String key that will be used to encrypt and
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* decrypt socket traffic
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* @param {number} timeout Dial timeout
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* @param {number} echoInterval Echo interval
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*/
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constructor(address, privateKey, timeout, echoInterval) {
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this.dial = new Dial(address, timeout, privateKey);
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this.echoInterval = echoInterval;
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this.streamHandler = null;
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}
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/**
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* Return a stream handler
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*
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* @param {object} callbacks A group of callbacks to call when needed
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*
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* @returns {Promise<streams.Streams>} The stream manager
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*
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*/
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async get(callbacks) {
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let self = this;
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if (this.streamHandler) {
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return this.streamHandler;
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}
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callbacks.connecting();
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let streamPaused = false,
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currentReceived = 0,
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currentUnpacked = 0;
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const shouldPause = () => {
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return currentReceived > currentUnpacked;
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};
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try {
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let conn = await this.dial.dial({
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inbound(data) {
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currentReceived += data.size;
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callbacks.traffic(data.size, 0);
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},
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inboundUnpacked(data) {
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currentUnpacked += data.length;
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if (currentUnpacked >= currentReceived) {
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currentUnpacked = 0;
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currentReceived = 0;
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}
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if (self.streamHandler !== null) {
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if (streamPaused && !shouldPause()) {
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streamPaused = false;
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self.streamHandler.resume();
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return;
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} else if (!streamPaused && shouldPause()) {
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streamPaused = true;
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self.streamHandler.pause();
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return;
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}
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}
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},
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outbound(data) {
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callbacks.traffic(0, data.length);
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}
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});
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let streamHandler = new streams.Streams(conn.reader, conn.sender, {
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echoInterval: self.echoInterval,
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echoUpdater(delay) {
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return callbacks.echo(delay);
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},
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cleared(e) {
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if (self.streamHandler === null) {
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return;
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}
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self.streamHandler = null;
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// Close connection first otherwise we may
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// risk sending things out
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conn.ws.close();
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callbacks.close(e);
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}
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});
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streamHandler.serve();
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callbacks.connected();
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this.streamHandler = streamHandler;
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} catch (e) {
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callbacks.failed(e);
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throw e;
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}
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return this.streamHandler;
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}
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}
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