Sanitize onboarding HTML rendering

[jonmartin721]

Summary

• escape onboarding token-step status content before inserting HTML
• sanitize popular repository suggestion rendering in onboarding
• add regression coverage for malicious repository metadata and saved token values

Testing

• eslint on changed files
• jest tests/onboarding.test.js --runInBand

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the security of the onboarding process by implementing robust HTML sanitization. It addresses potential cross-site scripting (XSS) vulnerabilities by escaping user-controlled data before it is rendered into the DOM, specifically for token validation status messages and popular repository suggestions. Comprehensive regression tests have also been added to ensure the effectiveness of these security measures against various forms of malicious input.

Highlights

• HTML Sanitization: Implemented HTML escaping for token-step status messages to prevent Cross-Site Scripting (XSS) vulnerabilities.
• Repository Suggestion Security: Ensured popular repository suggestions are sanitized before rendering to mitigate malicious data injection.
• Regression Testing: Added new regression tests to cover scenarios involving malicious repository metadata and saved token values.

Changelog

• popup/views/onboarding-view.js
  • Imported escapeHtml utility function for content sanitization.
  • Introduced getStatusMarkup helper to consistently render status messages with HTML escaping.
  • Created renderRepoSuggestion helper to safely render repository details, escaping all dynamic data.
  • Refactored token step status updates to use getStatusMarkup.
  • Applied escapeHtml to the token input value and the token URL link.
  • Updated popular repository rendering to utilize the new renderRepoSuggestion function.
• tests/onboarding.test.js
  • Imported _renderOnboardingStep for testing purposes.
  • Added a test case to verify that renderReposStep correctly escapes malicious repository metadata.
  • Included a test to confirm that renderOnboardingStep escapes saved token values and usernames to prevent XSS.

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[sentry]

Codecov Report

❌ Patch coverage is 67.85714% with 9 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
popup/views/onboarding-view.js	67.85%	9 Missing ⚠️

📢 Thoughts on this report? Let us know!

[gemini-code-assist]

Code Review

This pull request effectively addresses and prevents Cross-Site Scripting (XSS) vulnerabilities by correctly implementing HTML sanitization for user-provided data in the onboarding flow. The introduction of helper functions like getStatusMarkup and renderRepoSuggestion, along with a robust escapeHtml utility, centralizes the sanitization logic and applies it to all untrusted data sources. Regression tests have also been added to ensure malicious input is properly handled. There is one suggestion to improve the clarity of the renderRepoSuggestion function.

[gemini-code-assist]

This line constructs repoFullName from already-escaped parts. While this works due to how dataset API handles HTML entities, it's clearer and more robust to work with raw data for logic and escape only at the moment of rendering into HTML. This avoids confusion and makes the code's intent more explicit.

I suggest changing this line to use the raw owner and name. Consequently, you would then need to wrap repoFullName with escapeHtml() on line 36 where it's inserted into the data-repo attribute to ensure it's safely rendered.

Example for line 36:

<button class="add-repo-btn" data-repo="${escapeHtml(repoFullName)}">+</button>

Suggested change

	const repoFullName = `${owner}/${name}`;
	const repoFullName = `${repo?.owner?.login || 'unknown'}/${repo?.name || 'unknown'}`;

[jonmartin721]

Adjusted repoFullName to use the raw owner/name values and escape only at render time while updating the coverage on this branch. Thanks.

[jonmartin721]

Follow-up pushed in 78cb805: applied the repoFullName cleanup in renderRepoSuggestion and expanded onboarding sanitization tests to cover the token-step status paths that were dragging patch coverage.