spike(security): ship Trusted Types (report-only) for the search UI#52
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…search Worked-example spike for /spec/security/trusted-types/. Pagefind's search UI (pagefind-ui.js) builds its results list with innerHTML — 11 assignments, the only TrustedHTML sink on the site (our own scripts use none). So enforcing require-trusted-types-for would break search unless a default policy covers it; a default policy is the only option because Pagefind's bundled code assigns raw strings and can't opt into a named policy. - Vendor DOMPurify 3.4.11 as a self-hosted first-party asset (script-src 'self'), copied from node_modules by scripts/generate-assets.mjs at prebuild. - public/trusted-types-policy.js registers the `default` policy backed by DOMPurify (strips scripts/handlers, keeps Pagefind's a/p/mark/list markup). Loaded first in <head> so it exists before Pagefind mounts; fails closed and loud if DOMPurify is missing rather than registering a pass-through. - _headers: add Content-Security-Policy-Report-Only with require-trusted-types-for 'script'; trusted-types default, reporting to the existing /reports collector. Report-only is non-blocking — safe in prod, and measures real violations. - Ignore the vendored minified lib in eslint/prettier. To enforce: drop the `-Report-Only` suffix once reports are clean. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…policy Report-only testing surfaced two sinks the static innerHTML grep missed: - pagefind.js loads its own JS/WASM chunks via a TrustedScriptURL sink, not just innerHTML. The default policy now implements createScriptURL (same-origin allowlist; script-src 'self' is the backstop) alongside createHTML. - DOMPurify registers its own Trusted Types policy named "dompurify"; add it to the trusted-types allowlist next to default. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Report-only testing (thanks!) surfaced two sinks my static
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… into spike/trusted-types-search # Conflicts: # package-lock.json # package.json
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Makes the site a worked example of
/spec/security/trusted-types/(documented in #51) by actually wiring Trusted Types — starting in report-only so nothing breaks in production.The finding
Pagefind's search UI is the only thing on the site that would trip Trusted Types. The built
pagefind-ui.jsassignsinnerHTML11 times and uses no other sink (noeval,document.write,srcdoc); our own scripts use zero DOM-injection sinks. Because Pagefind's bundled code does rawel.innerHTML = …, it can't opt into a named policy — so the auto-applieddefaultpolicy is the only thing that can cover it, which means a general sanitiser (DOMPurify), not a<mark>-only one.What this PR does
/vendor/purify.min.js(stays underscript-src 'self'), copied fromnode_modulesbyscripts/generate-assets.mjsat prebuild.public/trusted-types-policy.jsregistering thedefaultTrusted Types policy backed byDOMPurify.sanitize(strips scripts/handlers, keeps Pagefind'sa/p/mark/list markup). Loaded first in<head>so it exists before Pagefind mounts. Fails closed and loud if DOMPurify is absent rather than registering an insecure pass-through.Content-Security-Policy-Report-Only: require-trusted-types-for 'script'; trusted-types default; report-to csp-endpointto_headers, reusing the existing/reportscollector. Report-only = non-blocking.Build, lint, and format all pass; both files land in
dist.npm run previewdoesn't apply_headers, so I couldn't drive a live search with Trusted Types enforced. To confirm DOMPurify preserves Pagefind's markup and results still render:npx wrangler pages dev dist, drop the-Report-Onlysuffix locally, and run a search.To enforce once verified: change
Content-Security-Policy-Report-Only→ fold the two directives into the mainContent-Security-Policy. If this lands, the Trusted Types page should get a "this site ships it" callout (as the reporting-endpoints page has).🤖 Generated with Claude Code