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所见所得的编辑器现在用得越来越多,原因之一,用户体验好。但是作为开发者,我们也应该清醒的认识到,这样的编辑器往往成了危险脚本、木马的温床。我们不能容忍蛀虫就在我们自己的东西里面滋生。
下面我就来尝试用正则替换的办法,使得编辑器里面的脚本无所遁形。可能我想的不是很全面,希望有漏网之鱼的,朋友们请提出。
脚本藏身之处不过有四:
1、<script>标签、<link>标签、<style>标签、iframe标签
2、on开头的标签属性
3、javascript(vbscript)伪协议
4、css的epression
下面是他们的字符串规则:
1、<(script|link|style|iframe)(.|\n)*<\/\1>\s*
2、\s*on[a-z]+\s*=\s*("[^"]+"|'[^']+'|[^\s]+)\s*(?=>)
3、\s*(href|src)\s*=\s*("\s*(javascript|vbscript):[^"]+"|'\s*(javascript|vbscript):[^']+'|(javascript|vbscript):[^\s]+)\s*(?=>)
4、epression\((.|\n)*\);?
了解他们的规则后,抓虫行动就水到渠成。下面看具体代码:
- <textarea id="bug" cols="80" rows="16">
- <button id="kick">抓虫1</button>
- <script>
- function kickBug(str) {
- return str.replace(/<(script|link|style|iframe)(.|\n)*\/\1>\s*/ig,"");
- }
- </script>
- <iframe></iframe>
- <link href='test.css'></link>
- <style>
- a {
- height:expression(alert('hei'));
- }
- </style>
- </textarea>
- <button id="kick">抓虫1</button>
- <script>
- function kickBug(str) {
- return str.replace(/<(script|link|style|iframe)(.|\n)*\/\1>\s*/ig,"");
- }
- if(!/msie/i.test(navigator.userAgent)){
- HTMLElement.prototype.__defineGetter__("innerText",function(){
- return this.textContent;
- });
- HTMLElement.prototype.__defineSetter__("innerText",function(text){
- this.textContent = text;
- });
- }
- document.getElementById("kick").onclick = function() {
- var bug = document.getElementById("bug");
- bug.innerText = kickBug(bug.innerText);
- }
- </script>
复制代码运行代码另存代码
- <textarea id="bug" cols="80" rows="5">
- <a οnclick="test();
- test1()" οnblur=
- "test3()">test</a>
- </textarea>
- <button id="kick">抓虫2</button>
- <script>
- function kickBug(str) {
- return str.replace(/<[a-z][^>]*\s*on[a-z]+\s*=[^>]+/ig,function($0,$1){
- return $0.replace(/\s*on[a-z]+\s*=\s*("[^"]+"|'[^']+'|[^\s]+)\s*/ig,"");
- });
- }
- if(!/msie/i.test(navigator.userAgent)){
- HTMLElement.prototype.__defineGetter__("innerText",function(){
- return this.textContent;
- });
- HTMLElement.prototype.__defineSetter__("innerText",function(text){
- this.textContent = text;
- });
- }
- document.getElementById("kick").onclick = function() {
- var bug = document.getElementById("bug");
- bug.innerText = kickBug(bug.innerText);
- }
- </script>
复制代码运行代码另存代码
- <textarea id="bug" cols="80" rows="5">
- <a οnclick="test();" href="
- jAvascript:alert('a')" href="jAvascript:"
- href="vbscript:alert()"
- >test</a>
- </textarea>
- <button id="kick">抓虫3</button>
- <script>
- function kickBug(str) {
- return str.replace(/<[a-z][^>]*\s*(href|src)\s*=[^>]+/ig,function($0,$1){
- $0 = $0.replace(/&#(6[5-9]|[78][0-9]|9[0789]|1[01][0-9]|12[012]);?/g,function($0,$1){return String.fromCharCode($1);});
- return $0.replace(/\s*(href|src)\s*=\s*("\s*(javascript|vbscript):[^"]+"|'\s*(javascript|vbscript):[^']+'|(javascript|vbscript):[^\s]+)/ig,"");
- });
- }
- if(!/msie/i.test(navigator.userAgent)){
- HTMLElement.prototype.__defineGetter__("innerText",function(){
- return this.textContent;
- });
- HTMLElement.prototype.__defineSetter__("innerText",function(text){
- this.textContent = text;
- });
- }
- document.getElementById("kick").onclick = function() {
- var bug = document.getElementById("bug");
- bug.innerText = kickBug(bug.innerText);
- }
- </script>
复制代码运行代码另存代码
- <textarea id="bug" cols="80" rows="5">
- expression()
- <a style="color:expression(
- 'red'
- )">test</a>
- </textarea>
- <button id="kick">抓虫4</button>
- <script>
- function kickBug(str) {
- return str.replace(/<[a-z][^>]*\s*style\s*=[^>]+/ig,function($0,$1){
- $0 = $0.replace(/&#(6[5-9]|[78][0-9]|9[0789]|1[01][0-9]|12[012]);?/g,function($0,$1){return String.fromCharCode($1);});
- return $0.replace(/\s*style\s*=\s*("[^"]+(expression)[^"]+"|'[^']+\2[^']+'|[^\s]+\2[^\s]+)\s*/ig,"");
- });
- }
- if(!/msie/i.test(navigator.userAgent)){
- HTMLElement.prototype.__defineGetter__("innerText",function(){
- return this.textContent;
- });
- HTMLElement.prototype.__defineSetter__("innerText",function(text){
- this.textContent = text;
- });
- }
- document.getElementById("kick").onclick = function() {
- var bug = document.getElementById("bug");
- bug.innerText = kickBug(bug.innerText);
- }
- </script>
复制代码运行代码另存代码
在winter的提醒下,加多了一个过滤iframe的。
加入过滤link标签、style标签
处理了类如e的html实体