telebit-relay.js/telebitd.js

520 lines
18 KiB
JavaScript

'use strict';
var url = require('url');
var PromiseA = require('bluebird');
var jwt = require('jsonwebtoken');
var Packer = require('proxy-packer');
function timeoutPromise(duration) {
return new PromiseA(function (resolve) {
setTimeout(resolve, duration);
});
}
var Devices = require('./lib/device-tracker');
var pipeWs = require('./lib/pipe-ws.js');
module.exports.store = { Devices: Devices };
module.exports.create = function (state) {
state.deviceLists = {};
//var deviceLists = {};
var activityTimeout = state.activityTimeout || 2*60*1000;
var pongTimeout = state.pongTimeout || 10*1000;
state.Devices = Devices;
var onTcpConnection = require('./lib/unwrap-tls').createTcpConnectionHandler(state);
// TODO Use a Single TCP Handler
// Issues:
// * dynamic ports are dedicated to a device or cluster
// * servernames could come in on ports that belong to a different device
// * servernames could come in that belong to no device
// * this could lead to an attack / security vulnerability with ACME certificates
// Solutions
// * Restrict dynamic ports to a particular device
// * Restrict the use of servernames
function onDynTcpConn(conn) {
var serviceport = this.address().port;
console.log('[DynTcpConn] new connection on', serviceport);
var remote = Devices.next(state.deviceLists, serviceport)
if (!remote) {
conn.write("[Sanity Error] I've got a blank space baby, but nowhere to write your name.");
conn.end();
try {
this.close();
} catch(e) {
console.error("[DynTcpConn] failed to close server:", e);
}
return;
}
conn.once('data', function (firstChunk) {
if (state.debug) { console.log("[DynTcp]", serviceport, "examining firstChunk from", Packer.socketToId(conn)); }
conn.pause();
conn.unshift(firstChunk);
var servername;
var hostname;
var str;
var m;
if (22 === firstChunk[0]) {
servername = (sni(firstChunk)||'').toLowerCase();
} else if (firstChunk[0] > 32 && firstChunk[0] < 127) {
str = firstChunk.toString();
m = str.match(/(?:^|[\r\n])Host: ([^\r\n]+)[\r\n]*/im);
hostname = (m && m[1].toLowerCase() || '').split(':')[0];
}
if (servername || hostname) {
if (servername) {
conn.write("TLS with sni is allowed only on standard ports. If you've registered '" + servername + "' use port 443.");
} else {
conn.write("HTTP with Host headers is not allowed on dynamic ports. If you've registered '" + hostname + "' use port 80.");
}
conn.end();
return;
}
// pipeWs(servername, servicename, client, remote, serviceport)
// remote.clients is managed as part of the piping process
if (state.debug) { console.log("[DynTcp]", serviceport, "piping to remote"); }
pipeWs(null, 'tcp', conn, remote, serviceport)
process.nextTick(function () { conn.resume(); });
});
}
function onWsConnection(ws, upgradeReq) {
var socketId = Packer.socketToId(upgradeReq.socket);
if (state.debug) { console.log('[ws] connection', socketId); }
var remotes = {};
var firstToken;
var authn = (upgradeReq.headers.authorization||'').split(/\s+/);
if (authn[0] && 'basic' === authn[0].toLowerCase()) {
try {
authn = new Buffer(authn[1], 'base64').toString('ascii').split(':');
firstToken = authn[1];
} catch (err) { }
}
if (!firstToken) {
firstToken = url.parse(upgradeReq.url, true).query.access_token;
}
if (firstToken) {
var err = addToken(firstToken, true);
if (err) {
sendTunnelMsg(null, [0, err], 'control');
ws.close();
return;
}
}
function logName() {
var result = Object.keys(remotes).map(function (jwtoken) {
return remotes[jwtoken].deviceId;
}).join(';');
return result || socketId;
}
function sendTunnelMsg(addr, data, service) {
ws.send(Packer.pack(addr, data, service), {binary: true});
}
function getBrowserConn(cid) {
var browserConn;
Object.keys(remotes).some(function (jwtoken) {
if (remotes[jwtoken].clients[cid]) {
browserConn = remotes[jwtoken].clients[cid];
return true;
}
});
return browserConn;
}
function closeBrowserConn(cid) {
var remote;
Object.keys(remotes).some(function (jwtoken) {
if (remotes[jwtoken].clients[cid]) {
remote = remotes[jwtoken];
return true;
}
});
if (!remote) {
return;
}
PromiseA.resolve().then(function () {
var conn = remote.clients[cid];
conn.tunnelClosing = true;
conn.end();
// If no data is buffered for writing then we don't need to wait for it to drain.
if (!conn.bufferSize) {
return timeoutPromise(500);
}
// Otherwise we want the connection to be able to finish, but we also want to impose
// a time limit for it to drain, since it shouldn't have more than 1MB buffered.
return new PromiseA(function (resolve) {
var timeoutId = setTimeout(resolve, 60*1000);
conn.once('drain', function () {
clearTimeout(timeoutId);
setTimeout(resolve, 500);
});
});
}).then(function () {
if (remote.clients[cid]) {
console.warn(cid, 'browser connection still present after calling `end`');
remote.clients[cid].destroy();
return timeoutPromise(500);
}
}).then(function () {
if (remote.clients[cid]) {
console.error(cid, 'browser connection still present after calling `destroy`');
delete remote.clients[cid];
}
}).catch(function (err) {
console.warn('failed to close browser connection', cid, err);
});
}
function addToken(jwtoken) {
if (remotes[jwtoken]) {
// return { message: "token sent multiple times", code: "E_TOKEN_REPEAT" };
return null;
}
var token;
try {
token = jwt.verify(jwtoken, state.secret);
} catch (e) {
token = null;
}
if (!token) {
return { message: "invalid access token", code: "E_INVALID_TOKEN" };
}
if (!Array.isArray(token.domains)) {
if ('string' === typeof token.name) {
token.domains = [ token.name ];
}
}
if (!Array.isArray(token.domains) || !token.domains.length) {
return { message: "invalid server name", code: "E_INVALID_NAME" };
}
if (token.domains.some(function (name) { return typeof name !== 'string'; })) {
return { message: "invalid server name", code: "E_INVALID_NAME" };
}
// Add the custom properties we need to manage this remote, then add it to all the relevant
// domains and the list of all this websocket's remotes.
token.deviceId = (token.device && (token.device.id || token.device.hostname)) || token.domains.join(',');
token.ws = ws;
token.upgradeReq = upgradeReq;
token.clients = {};
token.pausedConns = [];
ws._socket.on('drain', function () {
// the websocket library has it's own buffer apart from node's socket buffer, but that one
// is much more difficult to watch, so we watch for the lower level buffer to drain and
// then check to see if the upper level buffer is still too full to write to. Note that
// the websocket library buffer has something to do with compression, so I'm not requiring
// that to be 0 before we start up again.
if (ws.bufferedAmount > 128*1024) {
return;
}
token.pausedConns.forEach(function (conn) {
if (!conn.manualPause) {
// console.log('resuming', conn.tunnelCid, 'now that the web socket has caught up');
conn.resume();
}
});
token.pausedConns.length = 0;
});
token.domains.forEach(function (domainname) {
Devices.add(state.deviceLists, domainname, token);
});
if (!firstToken || firstToken === jwtoken) {
firstToken = jwtoken;
token.dynamicPorts = [];
token.dynamicNames = [];
function onDynTcpReady() {
var serviceport = this.address().port;
console.info('[DynTcpConn] Port', serviceport, 'now open for', token.deviceId);
token.dynamicPorts.push(serviceport);
Devices.add(state.deviceLists, serviceport, token);
var hri = require('human-readable-ids').hri;
var hrname = hri.random() + '.telebit.cloud';
token.dynamicNames.push(hrname);
// TODO restrict to authenticated device
// TODO pull servername from config
// TODO remove hrname on disconnect
Devices.add(state.deviceLists, hrname, token);
sendTunnelMsg(
null
, [ 2
, 'grant'
, [ ['ssh+https', hrname, 443 ]
, ['ssh', 'ssh.telebit.cloud', serviceport ]
, ['tcp', 'tcp.telebit.cloud', serviceport]
, ['https', hrname ]
]
]
, 'control'
);
}
try {
token.server = require('net').createServer(onDynTcpConn).listen(0, onDynTcpReady);
token.server.on('error', function (e) {
console.error("Server Error assigning a dynamic port to a new connection:", e);
});
} catch(e) {
// what a wonderful problem it will be the day that this bug needs to be fixed
// (i.e. there are enough users to run out of ports)
console.error("Error assigning a dynamic port to a new connection:", e);
}
}
remotes[jwtoken] = token;
console.info("[ws] authorized", socketId, "for", token.deviceId);
return null;
}
function removeToken(jwtoken) {
var remote = remotes[jwtoken];
if (!remote) {
return { message: 'specified token not present', code: 'E_INVALID_TOKEN'};
}
// Prevent any more browser connections being sent to this remote, and any existing
// connections from trying to send more data across the connection.
remote.domains.forEach(function (domainname) {
Devices.remove(state.deviceLists, domainname, remote);
});
remote.dynamicPorts.forEach(function (portnumber) {
Devices.remove(state.deviceLists, portnumber, remote);
});
remote.ws = null;
remote.upgradeReq = null;
if (remote.server) {
remote.serverPort = remote.server.address().port;
remote.server.close(function () {
console.log("[DynTcpConn] closing server for ", remote.serverPort);
remote.serverPort = null;
});
remote.server = null;
}
// Close all of the existing browser connections associated with this websocket connection.
Object.keys(remote.clients).forEach(function (cid) {
closeBrowserConn(cid);
});
delete remotes[jwtoken];
console.log("[ws] removed token '" + remote.deviceId + "' from", socketId);
return null;
}
var commandHandlers = {
add_token: addToken
, delete_token: function (token) {
if (token !== '*') {
return removeToken(token);
}
var err;
Object.keys(remotes).some(function (jwtoken) {
err = removeToken(jwtoken);
return err;
});
return err;
}
};
var packerHandlers = {
oncontrol: function (tun) {
var cmd, err;
try {
cmd = JSON.parse(tun.data.toString());
} catch (err) {}
if (!Array.isArray(cmd) || typeof cmd[0] !== 'number') {
var msg = 'received bad command "' + tun.data.toString() + '"';
console.warn(msg, 'from websocket', socketId);
sendTunnelMsg(null, [0, {message: msg, code: 'E_BAD_COMMAND'}], 'control');
return;
}
if (cmd[0] < 0) {
// We only ever send one command and we send it once, so we just hard coded the ID as 1.
if (cmd[0] === -1) {
if (cmd[1]) {
console.warn('received error response to hello from', socketId, cmd[1]);
}
}
else {
console.warn('received response to unknown command', cmd, 'from', socketId);
}
return;
}
if (cmd[0] === 0) {
console.warn('received dis-associated error from', socketId, cmd[1]);
return;
}
if (commandHandlers[cmd[1]]) {
err = commandHandlers[cmd[1]].apply(null, cmd.slice(2));
}
else {
err = { message: 'unknown command "'+cmd[1]+'"', code: 'E_UNKNOWN_COMMAND' };
}
sendTunnelMsg(null, [-cmd[0], err], 'control');
}
, onmessage: function (tun) {
var cid = Packer.addrToId(tun);
if (state.debug) { console.log("remote '" + logName() + "' has data for '" + cid + "'", tun.data.byteLength); }
var browserConn = getBrowserConn(cid);
if (!browserConn) {
sendTunnelMsg(tun, {message: 'no matching connection', code: 'E_NO_CONN'}, 'error');
return;
}
browserConn.write(tun.data);
// tunnelRead is how many bytes we've read from the tunnel, and written to the browser.
browserConn.tunnelRead = (browserConn.tunnelRead || 0) + tun.data.byteLength;
// If we have more than 1MB buffered data we need to tell the other side to slow down.
// Once we've finished sending what we have we can tell the other side to keep going.
// If we've already sent the 'pause' message though don't send it again, because we're
// probably just dealing with data queued before our message got to them.
if (!browserConn.remotePaused && browserConn.bufferSize > 1024*1024) {
sendTunnelMsg(tun, browserConn.tunnelRead, 'pause');
browserConn.remotePaused = true;
browserConn.once('drain', function () {
sendTunnelMsg(tun, browserConn.tunnelRead, 'resume');
browserConn.remotePaused = false;
});
}
}
, onpause: function (tun) {
var cid = Packer.addrToId(tun);
console.log('[TunnelPause]', cid);
var browserConn = getBrowserConn(cid);
if (browserConn) {
browserConn.manualPause = true;
browserConn.pause();
} else {
sendTunnelMsg(tun, {message: 'no matching connection', code: 'E_NO_CONN'}, 'error');
}
}
, onresume: function (tun) {
var cid = Packer.addrToId(tun);
console.log('[TunnelResume]', cid);
var browserConn = getBrowserConn(cid);
if (browserConn) {
browserConn.manualPause = false;
browserConn.resume();
} else {
sendTunnelMsg(tun, {message: 'no matching connection', code: 'E_NO_CONN'}, 'error');
}
}
, onend: function (tun) {
var cid = Packer.addrToId(tun);
console.log('[TunnelEnd]', cid);
closeBrowserConn(cid);
}
, onerror: function (tun) {
var cid = Packer.addrToId(tun);
console.warn('[TunnelError]', cid, tun.message);
closeBrowserConn(cid);
}
};
var unpacker = Packer.create(packerHandlers);
function refreshTimeout() {
lastActivity = Date.now();
}
function checkTimeout() {
// Determine how long the connection has been "silent", ie no activity.
var silent = Date.now() - lastActivity;
// If we have had activity within the last activityTimeout then all we need to do is
// call this function again at the soonest time when the connection could be timed out.
if (silent < activityTimeout) {
timeoutId = setTimeout(checkTimeout, activityTimeout-silent);
}
// Otherwise we check to see if the pong has also timed out, and if not we send a ping
// and call this function again when the pong will have timed out.
else if (silent < activityTimeout + pongTimeout) {
if (state.debug) { console.log('pinging', logName()); }
try {
ws.ping();
} catch (err) {
console.warn('failed to ping home cloud', logName());
}
timeoutId = setTimeout(checkTimeout, pongTimeout);
}
// Last case means the ping we sent before didn't get a response soon enough, so we
// need to close the websocket connection.
else {
console.warn('home cloud', logName(), 'connection timed out');
ws.close(1013, 'connection timeout');
}
}
function forwardMessage(chunk) {
refreshTimeout();
if (state.debug) { console.log('[ws] device => client : demultiplexing message ', chunk.byteLength, 'bytes'); }
//console.log(chunk.toString());
unpacker.fns.addChunk(chunk);
}
function hangup() {
clearTimeout(timeoutId);
console.log('[ws] device hangup', logName(), 'connection closing');
Object.keys(remotes).forEach(function (jwtoken) {
removeToken(jwtoken);
});
ws.terminate();
}
var lastActivity = Date.now();
var timeoutId;
timeoutId = setTimeout(checkTimeout, activityTimeout);
// Note that our websocket library automatically handles pong responses on ping requests
// before it even emits the event.
ws.on('ping', refreshTimeout);
ws.on('pong', refreshTimeout);
ws.on('message', forwardMessage);
ws.on('close', hangup);
ws.on('error', hangup);
// We only ever send one command and we send it once, so we just hard code the ID as 1
sendTunnelMsg(null, [1, 'hello', [unpacker._version], Object.keys(commandHandlers)], 'control');
}
return {
tcp: onTcpConnection
, ws: onWsConnection
, isClientDomain: Devices.exist.bind(null, state.deviceLists)
};
};