PrivateBin/js/legacy.js
2019-09-19 19:47:19 +02:00

309 lines
8.4 KiB
JavaScript

/**
* PrivateBin
*
* a zero-knowledge paste bin
*
* @see {@link https://github.com/PrivateBin/PrivateBin}
* @copyright 2012 Sébastien SAUVAGE ({@link http://sebsauvage.net})
* @license {@link https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License}
* @version 1.3
* @name Legacy
* @namespace
*
* IMPORTANT NOTICE FOR DEVELOPERS:
* The logic in this file is intended to run in legacy browsers. Avoid any use of:
* - jQuery (doesn't work in older browsers)
* - ES5 or newer in general
* - const/let, use the traditional var declarations instead
* - async/await or Promises, use traditional callbacks
* - shorthand function notation "() => output", use the full "function() {return output;}" style
* - IE doesn't support:
* - URL(), use the traditional window.location object
* - endsWith(), use indexof()
* - yes, this logic needs to support IE 6, to at least display the error message
*/
'use strict';
(function() {
/**
* compatibility check
*
* @name Check
* @class
*/
var Check = (function () {
var me = {};
/**
* Status of the initial check, true means it passed
*
* @private
* @prop {bool}
*/
var status = false;
/**
* Initialization check did run
*
* @private
* @prop {bool}
*/
var init = false;
/**
* blacklist of UserAgents (parts) known to belong to a bot
*
* @private
* @enum {Array}
* @readonly
*/
var badBotUA = [
'Bot',
'bot'
];
/**
* whitelist of top level domains to consider a secure context,
* regardless of protocol
*
* @private
* @enum {Array}
* @readonly
*/
var tld = [
'.onion',
'.i2p'
];
/**
* whitelist of hostnames to consider a secure context,
* regardless of protocol
*
* @private
* @enum {Array}
* @readonly
*/
// whitelists of TLDs & local hostnames
var hostname = [
'localhost',
'127.0.0.1',
'[::1]'
];
/**
* check if the context is secure
*
* @private
* @name Check.isSecureContext
* @function
* @return {bool}
*/
function isSecureContext()
{
// use .isSecureContext if available
if (window.isSecureContext === true || window.isSecureContext === false) {
return window.isSecureContext;
}
// HTTP is obviously insecure
if (window.location.protocol !== 'http:') {
return true;
}
// filter out actually secure connections over HTTP
for (var i = 0; i < tld.length; i++) {
if (
window.location.hostname.indexOf(
tld[i],
window.location.hostname.length - tld[i].length
) !== -1
) {
return true;
}
}
// whitelist localhost for development
for (var j = 0; j < hostname.length; j++) {
if (window.location.hostname === hostname[j]) {
return true;
}
}
// totally INSECURE http protocol!
return false;
}
/**
* checks whether this is a bot we dislike
*
* @private
* @name Check.isBadBot
* @function
* @return {bool}
*/
function isBadBot() {
// check whether a bot user agent part can be found in the current
// user agent
for (var i = 0; i < badBotUA.length; i++) {
if (navigator.userAgent.indexOf(badBotUA[i]) !== -1) {
return true;
}
}
return false;
}
/**
* checks whether this is an unsupported browser, via feature detection
*
* @private
* @name Check.isOldBrowser
* @function
* @return {bool}
*/
function isOldBrowser() {
// webcrypto support
if (!(
'crypto' in window &&
'getRandomValues' in window.crypto &&
'subtle' in window.crypto &&
'encrypt' in window.crypto.subtle &&
'decrypt' in window.crypto.subtle &&
'Uint8Array' in window &&
'Uint32Array' in window
)) {
return true;
}
// async & ES6 support
try {
eval('async () => {}');
} catch (e) {
if (e instanceof SyntaxError) {
return true;
} else {
throw e; // throws CSP error
}
}
return false;
}
/**
* shows an error message
*
* @private
* @name Check.showError
* @param {string} message
* @function
*/
function showError(message)
{
var element = document.getElementById('errormessage');
if (message.indexOf('<a') === -1) {
element.appendChild(
document.createTextNode(message)
);
} else {
element.innerHTML = message;
}
removeHiddenFromId('errormessage');
}
/**
* removes "hidden" CSS class from element with given ID
*
* @private
* @name Check.removeHiddenFromId
* @param {string} id
* @function
*/
function removeHiddenFromId(id)
{
var element = document.getElementById(id);
if (element) {
element.className = element.className.replace(/\bhidden\b/g, '');
}
}
/**
* returns if the check has concluded
*
* @name Check.getInit
* @function
* @return {bool}
*/
me.getInit = function()
{
return init;
};
/**
* returns the current status of the check
*
* @name Check.getStatus
* @function
* @return {bool}
*/
me.getStatus = function()
{
return status;
};
/**
* init on application start, returns an all-clear signal
*
* @name Check.init
* @function
*/
me.init = function()
{
// prevent bots from viewing a paste and potentially deleting data
// when burn-after-reading is set
if (isBadBot()) {
showError('I love you too, bot…');
init = true;
return;
}
if (isOldBrowser()) {
// some browsers (Chrome based ones) would have webcrypto support if using HTTPS
if (!isSecureContext()) {
removeHiddenFromId('insecurecontextnotice');
}
removeHiddenFromId('oldnotice');
init = true;
return;
}
if (!isSecureContext()) {
removeHiddenFromId('httpnotice');
}
init = true;
// only if everything passed, we set the status to true
status = true;
};
return me;
})();
// main application start, called when DOM is fully loaded
if (document.readyState === 'complete' || (!document.attachEvent && document.readyState === 'interactive')) {
Check.init();
} else {
if (document.addEventListener) {
// first choice is DOMContentLoaded event
document.addEventListener('DOMContentLoaded', Check.init, false);
// backup is window load event
window.addEventListener('load', Check.init, false);
} else {
// must be IE
document.attachEvent('onreadystatechange', Check.init);
window.attachEvent('onload', Check.init);
}
}
this.Legacy = {
Check: Check
};
}).call(this);