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<a href="https://www.zhihu.com/question/21979782&#10;" _src="https://www.zhihu.com/question/21979782
">https://www.zhihu.com/question/21979782&nbsp;</a><a href="https://content-security-policy.com/" _src="https://content-security-policy.com/">https://content-security-policy.com/</a> <p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">什么是CSP<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">CSP全称Content Security Policy ,可以直接翻译为内容安全策略,说白了,就是为了页面内容安全而制定的一系列防护策略. 通过CSP所约束的的规责指定可信的内容来源（这里的内容可以指脚本、图片、iframe、fton、style等等可能的远程的资源）。通过CSP协定，让WEB处于一个安全的运行环境中。<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">有什么用?<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">我们知道前端有个很著名的”同源策略”,简而言之,就是说一个页面的资源只能从与之同源的服务器获取,而不允许跨域获取.这样可以避免页面被注入恶意代码,影响安全.但是这个策略是个双刃剑,挡住恶意代码的同时也限制了前端的灵活性,那有没有一种方法既可以让我们可以跨域获取资源,又能防止恶意代码呢?<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">答案是当然有了,这就是csp,通过csp我们可以制定一系列的策略,从而只允许我们页面向我们允许的域名发起跨域请求,而不符合我们策略的恶意攻击则被挡在门外.从而实现<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">需要说明的一点是,目前主流的浏览器都已支持csp.所以我们可以放心大胆的用了.<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">指令说明<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">指令就是csp中用来定义策略的基本单位,我们可以使用单个或者多个指令来组合作用,功能防护我们的网站.<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">以下是常用的指令说明:<table cellspacing="0" cellpadding="0" width="785"><tbody><tr class="firstRow"><td valign="bottom" nowrap="nowrap" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">指令名</td><td valign="bottom" nowrap="nowrap" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">demo</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">说明</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">default-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39; cdn.example.com</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">默认策略,可以应用于js文件/图片/css/ajax请求等所有访问</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">script-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39; js.example.com</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义js文件的过滤策略</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">style-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39; css.example.com</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义css文件的过滤策略</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39; img.example.com</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义图片文件的过滤策略</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">connect-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39;</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义请求连接文件的过滤策略</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">font-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">font.example.com</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义字体文件的过滤策略</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">object-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39;</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义页面插件的过滤策略,如 &lt;object&gt;, &lt;embed&gt; 或者&lt;applet&gt;等元素</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">media-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">media.example.com</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义媒体的过滤策略,如 HTML6的 &lt;audio&gt;, &lt;video&gt;等元素</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">frame-src</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39;</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">定义加载子frmae的策略</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">sandbox</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">allow-forms allow-scripts</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;">沙盒模式,会阻止页面弹窗/js执行等,你可以通过添加allow-forms allow-same-origin allow-scripts allow-popups, allow-modals, allow-orientation-lock, allow-pointer-lock, allow-presentation, allow-popups-to-escape-sandbox, and allow-top-navigation 策略来放开相应的操作</td></tr><tr><td valign="top" width="129" style="border-color: silver; border-collapse: collapse; padding: 3px;">report-uri</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">/some-report-uri</td><td valign="bottom" width="425" style="border-color: silver; border-collapse: collapse; padding: 3px;"> </td></tr></tbody></table><p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">&nbsp;<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">指令值<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">所有以-src结尾的指令都可以用一下的值来定义过滤规则,多个规则之间可以用空格来隔开<table cellspacing="0" cellpadding="0" width="785"><tbody><tr class="firstRow"><td valign="bottom" nowrap="nowrap" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">值</td><td valign="bottom" nowrap="nowrap" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">demo</td><td valign="bottom" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">说明</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">*</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src *</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">允许任意地址的url,但是不包括 blob: filesystem: schemes.</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;none&#39;</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">object-src &#39;none&#39;</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">所有地址的咨询都不允许加载</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;self&#39;</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">script-src &#39;self&#39;</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">同源策略,即允许同域名同端口下,同协议下的请求</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">data:</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src &#39;self&#39; data:</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">允许通过data来请求咨询 (比如用Base64 编码过的图片).</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">domain.example.com</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src&nbsp;domain.example.com</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">允许特性的域名请求资源</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">*.example.com</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src *.example.com</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">允许从 example.com下的任意子域名加载资源</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">https://cdn.com</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src https://cdn.com</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">仅仅允许通过https协议来从指定域名下加载资源</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">https:</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">img-src https:</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">只允许通过https协议加载资源</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;unsafe-inline&#39;</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">script-src &#39;unsafe-inline&#39;</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">允许行内代码执行</td></tr><tr><td valign="top" width="147" style="border-color: silver; border-collapse: collapse; padding: 3px;">&#39;unsafe-eval&#39;</td><td valign="top" width="231" style="border-color: silver; border-collapse: collapse; padding: 3px;">script-src &#39;unsafe-eval&#39;</td><td valign="top" width="407" style="border-color: silver; border-collapse: collapse; padding: 3px;">允许不安全的动态代码执行,比如 JavaScript的&nbsp;eval()方法</td></tr></tbody></table><p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">&nbsp;<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">示例<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">default-src &#39;self&#39;; &nbsp;&nbsp;<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">只允许同源下的资源<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">&nbsp;<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">script-src &#39;self&#39;; &nbsp;&nbsp;&nbsp;&nbsp;<p style="line-height: 1.8; margin: 10px auto; color: rgb(51, 51, 51); font-family: Georgia, &quot;Times New Roman&quot;, Times, sans-serif; font-size: 14px; white-space: normal; background-color: rgb(255, 255, 255);">只允许同源下的js