在React SharePoint现代Web部件中安全使用dangerouslySetInnerHTML的正确性验证与测试方法咨询

First, let's recap your setup: you're building a SharePoint modern web part with rich text modals, using dangerouslySetInnerHTML and have added DOMPurify to sanitize user input. Let's break down your two questions clearly:

1. Is your current dangerouslySetInnerHTML security approach correct? Are there missing safeguards? #

Your core implementation is solid—using DOMPurify to sanitize user-provided HTML before passing it to dangerouslySetInnerHTML is the industry-standard way to mitigate XSS risks with this React property. Here's a breakdown of what you did right, plus a few extra safeguards you might want to add:

What you got right: #

• You installed dompurify (the gold standard for client-side HTML sanitization) and eslint-plugin-risxss (to catch unsafe dangerouslySetInnerHTML usage during development/code reviews).
• You replaced raw prop usage with sanitize(myprops.OurValue) to clean untrusted input before rendering, which is the critical first step to prevent XSS.

Potential missing safeguards: #

• Enforce ESLint rules: Make sure your ESLint config enables the risxss/no-dangerously-set-inner-html rule. This will throw errors if anyone uses dangerouslySetInnerHTML without sanitizing the input first, preventing accidental unsafe changes down the line.
• Customize DOMPurify's whitelist: By default, DOMPurify allows most safe HTML tags, but you can restrict it to only the tags/attributes your users actually need (e.g., <p>, <strong>, <a> with valid href). This reduces the attack surface further:

  import { sanitize } from 'dompurify';
  
  // Restrict to only basic formatting tags
  const sanitizeConfig = {
    ALLOWED_TAGS: ['p', 'strong', 'em', 'a', 'ul', 'li'],
    ALLOWED_ATTR: ['href', 'target']
  };
  
  // Use in your component:
  <div dangerouslySetInnerHTML={{ __html: sanitize(myprops.OurValue, sanitizeConfig) }} />
  

• Frontend input feedback: Add a basic warning in the property pane if users input potentially malicious code (like <script> tags). This isn't a replacement for sanitization, but it guides users away from risky input.
• Server-side sanitization (optional): If you're storing this HTML in SharePoint lists, add server-side sanitization when saving the data. This adds a second layer of defense in case client-side sanitization fails or is bypassed.

2. How to test if the sanitize method is working? #

You can validate DOMPurify's effectiveness in three practical ways:

Manual testing in the browser #

1. In your web part's property pane, input a malicious HTML snippet like:

   <script>alert('XSS Attack!');</script>
   <p>This is <strong>safe</strong> text, but the script should be removed.</p>
   <img src="fake.jpg" onerror="alert('Another XSS!')" />
   

2. Open the modal and inspect the rendered DOM using your browser's developer tools.
3. Verify that:
   • The <script> tag is completely removed.
   • The onerror attribute on the <img> tag is stripped.
   • The safe <p> and <strong> tags remain intact.

Unit testing with Jest (or your test runner) #

Write test cases to automate validation that sanitization works as expected. Example:

import { sanitize } from 'dompurify';

describe('DOMPurify sanitization', () => {
  it('removes script tags entirely', () => {
    const maliciousInput = '<script>alert("XSS")</script>Hello World';
    const sanitizedOutput = sanitize(maliciousInput);
    expect(sanitizedOutput).not.toContain('<script>');
    expect(sanitizedOutput).toBe('Hello World');
  });

  it('strips dangerous event attributes', () => {
    const maliciousInput = '<img src="test.jpg" onerror="alert(\'XSS\')" />';
    const sanitizedOutput = sanitize(maliciousInput);
    expect(sanitizedOutput).toBe('<img src="test.jpg" />');
  });

  it('preserves safe HTML formatting', () => {
    const safeInput = '<p>This is <strong>bold</strong> and <em>italic</em> text.</p>';
    const sanitizedOutput = sanitize(safeInput);
    expect(sanitizedOutput).toBe(safeInput);
  });
});

Debug via console logging #

In your React component, add a quick log to confirm the sanitized output before rendering:

const sanitizedContent = sanitize(myprops.OurValue);
console.log('Sanitized HTML Output:', sanitizedContent);

// Then render it:
<div dangerouslySetInnerHTML={{ __html: sanitizedContent }} />

Check your browser's console to confirm malicious code has been stripped before it's rendered to the DOM.

内容的提问来源于stack exchange，提问作者John John