241 lines
8.9 KiB
JavaScript
241 lines
8.9 KiB
JavaScript
/* eslint-disable complexity */
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/* eslint no-unused-expressions: ["error", { "allowShortCircuit": true, "allowTernary": true }],
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no-console: ["error", { allow: ["warn", "error"] }] */
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/* jshint esversion: 6, asi: true, node: true */
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// socket.js
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// private
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const debug = require('debug');
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const SSH = require('ssh2').Client;
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const CIDRMatcher = require('cidr-matcher');
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const validator = require('validator');
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const dnsPromises = require('dns').promises;
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const util = require('util');
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const { webssh2debug, auditLog, logError } = require('./logging');
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/**
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* parse conn errors
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* @param {object} socket Socket object
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* @param {object} err Error object
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*/
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function connError(socket, err) {
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let msg = util.inspect(err);
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const { session } = socket.request;
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if (err?.level === 'client-authentication') {
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msg = `Authentication failure user=${session.username} from=${socket.handshake.address}`;
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socket.emit('allowreauth', session.ssh.allowreauth);
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socket.emit('reauth');
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}
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if (err?.code === 'ENOTFOUND') {
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msg = `Host not found: ${err.hostname}`;
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}
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if (err?.level === 'client-timeout') {
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msg = `Connection Timeout: ${session.ssh.host}`;
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}
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logError(socket, 'CONN ERROR', msg);
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}
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/**
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* check ssh host is in allowed subnet
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* @param {object} socket Socket information
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*/
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async function checkSubnet(socket) {
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let ipaddress = socket.request.session.ssh.host;
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if (!validator.isIP(`${ipaddress}`)) {
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try {
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const result = await dnsPromises.lookup(socket.request.session.ssh.host);
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ipaddress = result.address;
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} catch (err) {
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logError(
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socket,
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'CHECK SUBNET',
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`${err.code}: ${err.hostname} user=${socket.request.session.username} from=${socket.handshake.address}`
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);
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socket.emit('ssherror', '404 HOST IP NOT FOUND');
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socket.disconnect(true);
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return;
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}
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}
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const matcher = new CIDRMatcher(socket.request.session.ssh.allowedSubnets);
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if (!matcher.contains(ipaddress)) {
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logError(
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socket,
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'CHECK SUBNET',
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`Requested host ${ipaddress} outside configured subnets / REJECTED user=${socket.request.session.username} from=${socket.handshake.address}`
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);
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socket.emit('ssherror', '401 UNAUTHORIZED');
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socket.disconnect(true);
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}
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}
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// public
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module.exports = function appSocket(socket) {
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let login = false;
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socket.once('disconnecting', (reason) => {
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webssh2debug(socket, `SOCKET DISCONNECTING: ${reason}`);
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if (login === true) {
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auditLog(
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socket,
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`LOGOUT user=${socket.request.session.username} from=${socket.handshake.address} host=${socket.request.session.ssh.host}:${socket.request.session.ssh.port}`
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);
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login = false;
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}
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});
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async function setupConnection() {
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// if websocket connection arrives without an express session, kill it
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if (!socket.request.session) {
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socket.emit('401 UNAUTHORIZED');
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webssh2debug(socket, 'SOCKET: No Express Session / REJECTED');
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socket.disconnect(true);
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return;
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}
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// If configured, check that requsted host is in a permitted subnet
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if (socket.request.session?.ssh?.allowedSubnets?.length > 0) {
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checkSubnet(socket);
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}
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const conn = new SSH();
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conn.on('banner', (data) => {
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// need to convert to cr/lf for proper formatting
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socket.emit('data', data.replace(/\r?\n/g, '\r\n').toString('utf-8'));
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});
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conn.on('handshake', (data => {
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socket.emit('setTerminalOpts', socket.request.session.ssh.terminal);
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socket.emit('menu');
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socket.emit('allowreauth', socket.request.session.ssh.allowreauth);
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socket.emit('title', `ssh://${socket.request.session.ssh.host}`);
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if (socket.request.session.ssh.header.background)
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socket.emit('headerBackground', socket.request.session.ssh.header.background);
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if (socket.request.session.ssh.header.name)
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socket.emit('header', socket.request.session.ssh.header.name);
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socket.emit(
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'footer',
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`ssh://${socket.request.session.username}@${socket.request.session.ssh.host}:${socket.request.session.ssh.port}`
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);
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}));
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conn.on('ready', () => {
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webssh2debug(
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socket,
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`CONN READY: LOGIN: user=${socket.request.session.username} from=${socket.handshake.address} host=${socket.request.session.ssh.host} port=${socket.request.session.ssh.port} allowreplay=${socket.request.session.ssh.allowreplay} term=${socket.request.session.ssh.term}`
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);
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auditLog(
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socket,
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`LOGIN user=${socket.request.session.username} from=${socket.handshake.address} host=${socket.request.session.ssh.host}:${socket.request.session.ssh.port}`
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);
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login = true;
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socket.emit('status', 'SSH CONNECTION ESTABLISHED');
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socket.emit('statusBackground', 'green');
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socket.emit('allowreplay', socket.request.session.ssh.allowreplay);
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const { term, cols, rows } = socket.request.session.ssh;
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conn.shell({ term, cols, rows }, (err, stream) => {
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if (err) {
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logError(socket, `EXEC ERROR`, err);
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conn.end();
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socket.disconnect(true);
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return;
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}
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socket.once('disconnect', (reason) => {
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webssh2debug(socket, `CLIENT SOCKET DISCONNECT: ${util.inspect(reason)}`);
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conn.end();
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socket.request.session.destroy();
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});
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socket.on('error', (errMsg) => {
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webssh2debug(socket, `SOCKET ERROR: ${errMsg}`);
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logError(socket, 'SOCKET ERROR', errMsg);
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conn.end();
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socket.disconnect(true);
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});
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socket.on('control', (controlData) => {
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if (controlData === 'replayCredentials' && socket.request.session.ssh.allowreplay) {
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stream.write(`${socket.request.session.userpassword}\n`);
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}
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if (controlData === 'reauth' && socket.request.session.username && login === true) {
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auditLog(
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socket,
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`LOGOUT user=${socket.request.session.username} from=${socket.handshake.address} host=${socket.request.session.ssh.host}:${socket.request.session.ssh.port}`
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);
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login = false;
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conn.end();
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socket.disconnect(true);
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}
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webssh2debug(socket, `SOCKET CONTROL: ${controlData}`);
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});
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socket.on('resize', (data) => {
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stream.setWindow(data.rows, data.cols);
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webssh2debug(socket, `SOCKET RESIZE: ${JSON.stringify([data.rows, data.cols])}`);
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});
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socket.on('data', (data) => {
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stream.write(data);
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});
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stream.on('data', (data) => {
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socket.emit('data', data.toString('utf-8'));
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});
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stream.on('close', (code, signal) => {
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webssh2debug(socket, `STREAM CLOSE: ${util.inspect([code, signal])}`);
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if (socket.request.session?.username && login === true) {
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auditLog(
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socket,
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`LOGOUT user=${socket.request.session.username} from=${socket.handshake.address} host=${socket.request.session.ssh.host}:${socket.request.session.ssh.port}`
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);
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login = false;
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}
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if (code !== 0 && typeof code !== 'undefined')
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logError(socket, 'STREAM CLOSE', util.inspect({ message: [code, signal] }));
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socket.disconnect(true);
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conn.end();
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});
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stream.stderr.on('data', (data) => {
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console.error(`STDERR: ${data}`);
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});
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});
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});
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conn.on('end', (err) => {
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if (err) logError(socket, 'CONN END BY HOST', err);
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webssh2debug(socket, 'CONN END BY HOST');
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socket.disconnect(true);
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});
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conn.on('close', (err) => {
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if (err) logError(socket, 'CONN CLOSE', err);
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webssh2debug(socket, 'CONN CLOSE');
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socket.disconnect(true);
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});
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conn.on('error', (err) => connError(socket, err));
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conn.on('keyboard-interactive', (_name, _instructions, _instructionsLang, _prompts, finish) => {
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webssh2debug(socket, 'CONN keyboard-interactive');
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finish([socket.request.session.userpassword]);
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});
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if (
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socket.request.session.username &&
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(socket.request.session.userpassword || socket.request.session.privatekey) &&
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socket.request.session.ssh
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) {
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// console.log('hostkeys: ' + hostkeys[0].[0])
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const { ssh } = socket.request.session;
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ssh.username = socket.request.session.username;
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ssh.password = socket.request.session.userpassword;
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ssh.tryKeyboard = true;
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ssh.debug = debug('ssh2');
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conn.connect(ssh);
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} else {
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webssh2debug(
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socket,
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`CONN CONNECT: Attempt to connect without session.username/password or session varialbles defined, potentially previously abandoned client session. disconnecting websocket client.\r\nHandshake information: \r\n ${util.inspect(
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socket.handshake
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)}`
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);
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socket.emit('ssherror', 'WEBSOCKET ERROR - Refresh the browser and try again');
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socket.request.session.destroy();
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socket.disconnect(true);
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}
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}
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setupConnection();
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};
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