wildduck/lib/pop3/server.js
2021-05-15 20:29:11 +03:00

452 lines
15 KiB
JavaScript

'use strict';
const EventEmitter = require('events');
const net = require('net');
const tls = require('tls');
const crypto = require('crypto');
const tlsOptions = require('../../imap-core/lib/tls-options');
const shared = require('nodemailer/lib/shared');
const POP3Connection = require('./connection');
const punycode = require('punycode/');
const base32 = require('base32.js');
const errors = require('../errors');
const CLOSE_TIMEOUT = 1 * 1000; // how much to wait until pending connections are terminated
class POP3Server extends EventEmitter {
constructor(options) {
super();
this.options = options || {};
this.updateSecureContext();
// apply shorthand handlers
['onAuth', 'onListMessages', 'onFetchMessage', 'onUpdate'].forEach(handler => {
if (typeof this.options[handler] === 'function') {
this[handler] = this.options[handler];
}
});
/**
* Timeout after close has been called until pending connections are forcibly closed
*/
this._closeTimeout = false;
/**
* A set of all currently open connections
*/
this.connections = new Set();
this.logger = shared.getLogger(this.options, {
component: this.options.component || 'pop3-server'
});
if (this.options.secure && !this.options.needsUpgrade) {
this.server = net.createServer(this.options, socket => {
this._handleProxy(socket, (err, socketOptions) => {
if (err) {
// ignore, should not happen
}
if (this.options.secured) {
return this.connect(socket, socketOptions);
}
this._upgrade(socket, (err, tlsSocket) => {
if (err) {
return this._onError(err);
}
this.connect(tlsSocket, socketOptions);
});
});
});
} else {
this.server = net.createServer(this.options, socket => {
this._handleProxy(socket, (err, socketOptions) => {
if (err) {
// ignore, should not happen
}
this.connect(socket, socketOptions);
});
});
}
this._setListeners();
}
_upgrade(socket, callback) {
let socketOptions = {
secureContext: this.secureContext.get('*'),
isServer: true,
server: this.server,
SNICallback: (servername, cb) => {
// eslint-disable-next-line new-cap
this.options.SNICallback(this._normalizeHostname(servername), (err, context) => {
if (err) {
this.logger.error(
{
tnx: 'sni',
servername,
err
},
'Failed to fetch SNI context for servername %s',
servername
);
}
return cb(null, context || this.secureContext.get('*'));
});
}
};
let remoteAddress = socket.remoteAddress;
let returned = false;
let onError = err => {
if (returned) {
return;
}
returned = true;
if (err && /SSL[23]*_GET_CLIENT_HELLO|ssl[23]*_read_bytes|ssl_bytes_to_cipher_list/i.test(err.message)) {
let message = err.message;
err.message = 'Failed to establish TLS session';
err.code = err.code || 'TLSError';
err.meta = {
protocol: 'pop3',
stage: 'connect',
message,
remoteAddress
};
}
if (!err || !err.message) {
err = new Error('Socket closed while initiating TLS');
err.code = 'SocketError';
err.meta = {
protocol: 'pop3',
stage: 'connect',
remoteAddress
};
}
callback(err);
};
// remove all listeners from the original socket besides the error handler
socket.once('error', onError);
// upgrade connection
let tlsSocket = new tls.TLSSocket(socket, socketOptions);
let onCloseError = hadError => {
if (hadError) {
return onError();
}
};
tlsSocket.once('close', onCloseError);
tlsSocket.once('error', onError);
tlsSocket.once('_tlsError', onError);
tlsSocket.once('clientError', onError);
tlsSocket.once('tlsClientError', onError);
tlsSocket.on('secure', () => {
socket.removeListener('error', onError);
tlsSocket.removeListener('close', onCloseError);
tlsSocket.removeListener('error', onError);
tlsSocket.removeListener('_tlsError', onError);
tlsSocket.removeListener('clientError', onError);
tlsSocket.removeListener('tlsClientError', onError);
if (returned) {
try {
tlsSocket.end();
} catch (E) {
//
}
return;
}
returned = true;
return callback(null, tlsSocket);
});
}
updateSecureContext(options) {
Object.keys(options || {}).forEach(key => {
this.options[key] = options[key];
});
let defaultTlsOptions = tlsOptions(this.options);
this.secureContext = new Map();
this.secureContext.set('*', tls.createSecureContext(defaultTlsOptions));
let ctxMap = this.options.sniOptions || {};
// sniOptions is either an object or a Map with domain names as keys and TLS option objects as values
if (typeof ctxMap.get === 'function') {
ctxMap.forEach((ctx, servername) => {
this.secureContext.set(this._normalizeHostname(servername), tls.createSecureContext(tlsOptions(ctx)));
});
} else {
Object.keys(ctxMap).forEach(servername => {
this.secureContext.set(this._normalizeHostname(servername), tls.createSecureContext(tlsOptions(ctxMap[servername])));
});
}
if (this.options.secure) {
// appy changes
Object.keys(defaultTlsOptions || {}).forEach(key => {
if (!(key in this.options)) {
this.options[key] = defaultTlsOptions[key];
}
});
// ensure SNICallback method
if (typeof this.options.SNICallback !== 'function') {
// create default SNI handler
this.options.SNICallback = (servername, cb) => {
cb(null, this.secureContext.get(servername));
};
}
}
}
_normalizeHostname(hostname) {
return punycode.toUnicode((hostname || '').toString().trim()).toLowerCase();
}
_setListeners() {
this.server.on('listening', () => this._onListening());
this.server.on('close', () => this._onClose());
this.server.on('error', err => this._onError(err));
}
/**
* Called when server started listening
*
* @event
*/
_onListening() {
let address = this.server.address();
this.logger.info(
//
{
tnx: 'listen',
host: address.address,
port: address.port,
secure: !!this.options.secure,
protocol: 'POP3'
},
'%s%s Server listening on %s:%s',
this.options.secure ? 'Secure ' : '',
'POP3',
address.family === 'IPv4' ? address.address : '[' + address.address + ']',
address.port
);
}
/**
* Called when server is closed
*
* @event
*/
_onClose() {
this.logger.info(
{
tnx: 'closed'
},
'POP3 Server closed'
);
this.emit('close');
}
/**
* Called when an error occurs with the server
*
* @event
*/
_onError(err) {
errors.notifyConnection(false, err);
this.emit('error', err);
}
_handleProxy(socket, callback) {
let socketOptions = {
id: base32.encode(crypto.randomBytes(10)).toLowerCase()
};
if (
!this.options.useProxy ||
(Array.isArray(this.options.useProxy) && !this.options.useProxy.includes(socket.remoteAddress) && !this.options.useProxy.includes('*'))
) {
socketOptions.ignore = this.options.ignoredHosts && this.options.ignoredHosts.includes(socket.remoteAddress);
return setImmediate(() => callback(null, socketOptions));
}
if (!this.options.useProxy) {
return setImmediate(callback);
}
let chunks = [];
let chunklen = 0;
let socketReader = () => {
let chunk;
while ((chunk = socket.read()) !== null) {
for (let i = 0, len = chunk.length; i < len; i++) {
let chr = chunk[i];
if (chr === 0x0a) {
socket.removeListener('readable', socketReader);
chunks.push(chunk.slice(0, i + 1));
chunklen += i + 1;
let remainder = chunk.slice(i + 1);
if (remainder.length) {
socket.unshift(remainder);
}
let header = Buffer.concat(chunks, chunklen).toString().trim();
let params = (header || '').toString().split(' ');
let commandName = params.shift().toUpperCase();
if (commandName !== 'PROXY') {
try {
socket.end('-ERR Invalid PROXY header\r\n');
} catch (E) {
// ignore
}
return;
}
if (params[1]) {
socketOptions.remoteAddress = params[1].trim().toLowerCase();
socketOptions.ignore = this.options.ignoredHosts && this.options.ignoredHosts.includes(socketOptions.remoteAddress);
if (!socketOptions.ignore) {
this.logger.info(
{
tnx: 'proxy',
cid: socketOptions.id,
proxy: params[1].trim().toLowerCase()
},
'[%s] PROXY from %s through %s',
socketOptions.id,
params[1].trim().toLowerCase(),
params[2].trim().toLowerCase()
);
}
if (params[3]) {
socketOptions.remotePort = Number(params[3].trim()) || socketOptions.remotePort;
}
}
return callback(null, socketOptions);
}
}
chunks.push(chunk);
chunklen += chunk.length;
}
};
socket.on('readable', socketReader);
}
connect(socket, socketOptions) {
let connection = new POP3Connection(this, socket, socketOptions);
this.connections.add(connection);
connection.once('error', err => {
this.connections.delete(connection);
this._onError(err);
});
connection.once('close', () => {
this.connections.delete(connection);
});
connection.init();
}
close(callback) {
let connections = this.connections.size;
let timeout = this.options.closeTimeout || CLOSE_TIMEOUT;
// stop accepting new connections
this.server.close(() => {
clearTimeout(this._closeTimeout);
if (typeof callback === 'function') {
return callback();
}
});
// close active connections
if (connections) {
this.logger.info(
{
tnx: 'close'
},
'Server closing with %s pending connection%s, waiting %s seconds before terminating',
connections,
connections !== 1 ? 's' : '',
timeout / 1000
);
}
this._closeTimeout = setTimeout(() => {
connections = this.connections.size;
if (connections) {
this.logger.info(
{
tnx: 'close'
},
'Closing %s pending connection%s to close the server',
connections,
connections !== 1 ? 's' : ''
);
this.connections.forEach(connection => {
connection.close();
});
}
}, timeout);
}
/**
* Authentication handler. Override this
*
* @param {Object} auth Authentication options
* @param {Object} session Session object
* @param {Function} callback Callback to run once the user is authenticated
*/
onAuth(auth, session, callback) {
return callback(null, {
message: 'Authentication not implemented'
});
}
// called when a message body needs to be fetched
onFetchMessage(message, session, callback) {
// should return a stream object
return callback(null, false);
}
// called when session is finished and messages need to be updated/deleted
onUpdate(update, session, callback) {
return callback(null, false);
}
/**
* Message listing handler. Override this
*
* @param {Object} session Session object
* @param {Function} callback Callback to run with message listing
*/
onListMessages(session, callback) {
// messages are objects {id: 'abc', size: 123, seen: true}
return callback(null, {
messages: [],
count: 0,
size: 0
});
}
listen(...args) {
this.server.listen(...args);
}
}
module.exports = POP3Server;