EPUB Content Sanitization and Sandbox Hardening#440
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- Implement `sanitizeEpubDocument` and `createEpubSanitizerHook` using DOMPurify - Integrate sanitization hook into `EpubLoader` and `useReaderEpub` - Remove `allow-scripts` from reader iframe sandbox in web app - Remove `allow-scripts` from CSP sandbox directive in worker file server - Add unit tests for document sanitization - Update existing tests to match hardened sandbox configuration This change addresses a critical security item in AGENTS.md by ensuring all EPUB content is sanitized before rendering and enforcing a script-free environment via browser-level sandbox controls. Co-authored-by: d-oit <6849456+d-oit@users.noreply.github.com>
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| Category | Results |
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| Security | 3 high |
🟢 Metrics 21 complexity · 2 duplication
Metric Results Complexity 21 Duplication 2
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…idempotency Addresses the two Codacy high-severity findings on PR #440: 1. Security: replace FORBID_TAGS-only with an explicit ALLOWED_TAGS allowlist (EPUB_BODY/HEAD/STRUCTURAL_TAGS). The denylist approach is a known foot-gun for untrusted HTML because a future DOMPurify version that ships a new default-permitted tag would silently let it through. The new allowlist also drops form/input/button/select/ textarea, blocking phishing forms embedded in EPUBs. 2. ErrorProne: replace WHOLE_DOCUMENT=true + IN_PLACE=true with a deterministic three-pass implementation: (a) DOMPurify allowlist on a clone (RETURN_DOM:true) (b) live documentElement.replaceChildren() with sanitized children (c) sanitizeDom() for href-scheme + event-attr enforcement This avoids the WHOLE_DOCUMENT mutation foot-gun and is provably idempotent: a new 'hook is safe to invoke multiple times' test asserts the DOM is identical after N invocations. Also added: structural tags (html/head/body) so DOMPurify no longer drops the document wrapper, and 7 new sanitizer tests covering forms, unknown tags, event-handler stripping, idempotency, empty input, and null-document defensive paths. The double registration in useReaderEpub.ts vs epub-loader.ts is intentional and now documented: each creates its own rendition, and the hook is idempotent even if the renditions are ever unified.
…plementation - Implement `sanitizeEpubDocument` with an explicit `ALLOWED_TAGS` allowlist - Address Codacy findings by replacing denylist-only approach - Use a deterministic three-pass implementation to avoid mutation foot-guns: (a) DOMPurify on a clone with `RETURN_DOM: true` (b) Sync attributes and children back to live document (c) Post-process with `sanitizeDom` for scheme validation - Remove phishing surface by stripping `form`, `input`, `button`, etc. - Preserve structural tags (`html`, `head`, `body`) and head metadata - Add unit tests for phishing prevention, structural integrity, and idempotency - Harden reader sandbox and CSP by removing `allow-scripts` Addresses high-severity security debt in AGENTS.md. Co-authored-by: d-oit <6849456+d-oit@users.noreply.github.com>
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Implemented a multi-layered security enhancement for the EPUB reader:
DOMPurify-backed sanitizer for EPUB documents that strips dangerous tags (script, iframe, object) while preserving necessary styling tags (link, style, meta).allow-scriptsfrom the rendition iframe's sandbox attribute, preventing any potential script execution even if sanitization is bypassed.allow-scriptsfrom the sandbox directive.PR created automatically by Jules for task 10893744634142080706 started by @d-oit