具有内容安全策略的reCAPTCHA [英] reCAPTCHA with Content Security Policy

问题描述

我正在尝试使reCAPTCHA与严格的内容安全政策一起使用。这是我拥有的基本版本，可以正常运行：

I'm trying to make reCAPTCHA work along with a strict Content Security Policy. This is the basic version I have, which works correctly:

HTML

<script src='//www.google.com/recaptcha/api.js' async defer></script>

HTTP标头

Content-Security-Policy: default-src 'self'; script-src 'self' www.google.com www.gstatic.com; style-src 'self' https: 'unsafe-inline'; frame-src www.google.com;

但是，我想摆脱 insafe-inline style-src 部分中的code>。在文档，其中写道：

However, I would like to get rid of the unsafe-inline in the style-src section. On the documentation, it is written that:

我们建议使用CSP3中记录的基于随机数的方法。确保将您的随机数包含在reCAPTCHA api.js脚本标记中，其余的将由我们处理。

We recommend using the nonce-based approach documented with CSP3. Make sure to include your nonce in the reCAPTCHA api.js script tag, and we'll handle the rest.

但是我可以使其工作...这就是我尝试过的：

But I can't make it work... This is what I tried:

HTML

<script src='//www.google.com/recaptcha/api.js' nonce="{NONCE}" async defer></script>

HTTP标头

Content-Security-Policy: default-src 'self'; script-src 'self' https: 'nonce-{NONCE}'; style-src 'self' 'nonce-{NONCE}'; child-src www.google.com;

这是我在Chrome 53上看到的错误：

And this is the error I get on Chrome 53:

拒绝应用内联样式，因为它违反了以下内容安全策略指令： style-src'self'https：'nonce- {NONCE}'。

我缺少什么？

推荐答案

我不相信reCAPTCHA支持CSP不允许使用内联样式。我在reCAPTCHA Github存储库中发现了这个未解决的问题。

I no not believe reCAPTCHA supports CSP without allowing inline styles. I found this open issue in the reCAPTCHA Github repository.

使用CSP的带有reCAPTCHA的示例页面可以正常工作，因为没有定义 style-src 或 default-src 。对页面DOM的检查发现了插入的div：

This sample page with reCAPTCHA using CSP works because it does not define style-src or default-src. An inspection of the page's DOM reveals this inserted div:

<div class="g-recaptcha" data-sitekey="6LdOLRgTAAAAAPYECt9KLIL_LLwOuuuHAUw7QUTm">
    <div style="width: 304px; height: 78px;">
        <div>
            <iframe src="https://www.google.com/recaptcha/api2/anchor?k=6LdOLRgTAAAAAPYECt9KLIL_LLwOuuuHAUw7QUTm&amp;co=aHR0cHM6Ly9jc3AtZXhwZXJpbWVudHMuYXBwc3BvdC5jb206NDQz&amp;hl=en&amp;v=r20160926121436&amp;size=normal&amp;cb=g72al0v10dxg" title="recaptcha widget" width="304" height="78" role="presentation" frameborder="0" scrolling="no" name="undefined"></iframe>
        </div>
        <textarea id="g-recaptcha-response" name="g-recaptcha-response" class="g-recaptcha-response" style="width: 250px; height: 40px; border: 1px solid #c1c1c1; margin: 10px 25px; padding: 0px; resize: none;  display: none; "></textarea>
    </div>
</div>

textarea 的内联样式的计算结果为 MammJ3J + TGIHdHxYsGLjD6DzRU0ZmxXKZ2DvTePAF0o = 由以下方式确定：

The inline style for textarea evaluates to MammJ3J+TGIHdHxYsGLjD6DzRU0ZmxXKZ2DvTePAF0o= as determined by:

echo -n "width: 250px; height: 40px; border: 1px solid #c1c1c1; margin: 10px 25px; padding: 0px; resize: none;  display: none; " | openssl dgst -sha256 -binary | base64

这与错误消息中指示的哈希值匹配。但是，在 style-src 中包含散列不适用于Chrome 此打开的错误。看来， unsafe-hashed-attributes 会支持该功能，据我所知，该功能尚未出现在Chrome版本中。

This matches the hash indicated in your error message. However, including the hash in style-src does not work for inline styles in Chrome per this open bug. It appears this will be supported with unsafe-hashed-attributes which as far as I can tell hasn't made it to a Chrome release.

对于它的价值，添加哈希使其可以在Firefox中使用。

For what it's worth, adding the hash makes it work in Firefox.

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