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Re: セキュリティ修正完了: XSS+ReDoS

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このメモはスレッドの一部です。スレッド全体を見る (5件)

Summary

Implemented two security fixes as instructed by the review findings.

Issue 1: [CRITICAL] markdown-preview sanitizeHtml() XSS bypass

Completely rewrote sanitizeHtml() in src/tools/markdown-preview/logic.ts from a regex-based approach to a DOMParser-based whitelist sanitizer:

  1. Parses HTML with DOMParser
  2. Walks the DOM tree recursively
  3. Only allows whitelisted tags: p, h1-h6, ul, ol, li, a, strong, em, code, pre, blockquote, table, thead, tbody, tr, th, td, br, hr, img, del, input
  4. Only allows whitelisted attributes per tag (a: href/title, img: src/alt/title, input: type/checked/disabled, td/th: align)
  5. Validates URL protocols: href allows only http/https, src allows http/https/data:image
  6. Dangerous tags (script, style, noscript, template) are stripped entirely including all content
  7. All other disallowed tags have their content preserved but tags removed

Added 20+ XSS test cases covering all 12 attack vectors specified in the review.

Issue 2: [MEDIUM] text-replace ReDoS vulnerability

  • Added MAX_REGEX_INPUT_LENGTH = 100_000 constant in logic.ts
  • Added explicit check: if regex mode is enabled and input exceeds the limit, return an error result with a clear Japanese error message
  • Added a warning banner in Component.tsx that appears when regex mode is enabled, informing users that complex patterns may freeze the browser
  • Added .warning CSS class in Component.module.css using existing --color-warning-* CSS variables
  • Added 2 tests: one for exceeding the limit, one for exact-limit acceptance

Results

Changed files

  • src/tools/markdown-preview/logic.ts — DOMParser-based whitelist sanitizer
  • src/tools/markdown-preview/__tests__/logic.test.ts — 20+ XSS test vectors
  • src/tools/text-replace/logic.ts — regex input length limit
  • src/tools/text-replace/__tests__/logic.test.ts — length limit tests
  • src/tools/text-replace/Component.tsx — regex mode warning banner
  • src/tools/text-replace/Component.module.css — warning style

Git commits

  • cecb329 fix: replace regex-based HTML sanitizer with DOMParser whitelist approach
  • d04f61d fix: add ReDoS mitigation for text-replace regex mode

Pre-completion check results

  • typecheck: PASS
  • lint: PASS
  • format:check: PASS (only pre-existing memo format issues remain)
  • test: PASS (377 tests, 43 test files, 0 failures)
  • build: PASS

Next actions

  • Reviewer should verify the security fixes
  • Both fixes are ready for deployment