JavaScript：通过获取本机函数来防止函数覆盖

Question

JavaScript：通过获取本机函数来防止函数覆盖

javascriptsecurity

3

如何防止javascript函数被重新定义并获取标准函数？

让我解释一下：

我有一个模块，专门用于检测操纵DOM的浏览器扩展程序。

然而，该扩展程序可以重新定义任何原生函数。

因此，我尝试通过iframe元素获取原生函数。

在以下代码中，我这样做了，但是observe方法出现了非法调用错误。

( function() { 

//protection against overriding of MutationObserver and XMLHttpRequest method
var iframe_tag = document.createElement('iframe');
document.body.appendChild(iframe_tag);
window.MutationObserver = iframe_tag.contentWindow.MutationObserver;
window.XMLHttpRequest = iframe_tag.contentWindow.XMLHttpRequest;

// Callback function to execute when mutations are observed
var callback = function(mutationsList, observer) {
  //Here we detected a change....
};

// binding to window object --> does not work Illegal invocation
MutationObserver.prototype.observe = MutationObserver.prototype.observe.bind(this);

// Create an observer instance linked to the callback function
var bodyobserver = new MutationObserver(callback);

// Start observing the target node for configured mutations
bodyobserver .observe(document.body, config);


} ) ();

这样做对吗/我做错了什么？

- Laurent B

你为什么要尝试将 MutationObserver 的方法绑定到 window 上？ - Bergi

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- klugjo · Accepted Answer

你应该用整个原型覆盖它：

window.objectToOverride.prototype = Object.create(iframe.objectToOverride.prototype)

结果：

( function() { 

//protection against overriding of MutationObserver and XMLHttpRequest method
var iframe_tag = document.createElement('iframe');
document.body.appendChild(iframe_tag);
window.MutationObserver.prototype = Object.create(iframe_tag.contentWindow.MutationObserver.prototype);
window.XMLHttpRequest.prototype = Object.create(iframe_tag.contentWindow.XMLHttpRequest.prototype);

// Callback function to execute when mutations are observed
var callback = function(mutationsList, observer) {
  //Here we detected a change....
};

// binding to window object --> does not work Illegal invocation
// Not needed anymore
//MutationObserver.prototype.observe = MutationObserver.prototype.observe.bind(this);

// Create an observer instance linked to the callback function
var bodyobserver = new MutationObserver(callback);

// Start observing the target node for configured mutations
bodyobserver.observe(document.body, {});


} ) ();