Andrey Antukh c39e3e8301
✨ Strictly validate uploads against file bytes on disk (#12801)
* ✨ Strictly validate uploads against file bytes on disk

Sniff the real content type of every upload with simplemagic magic
bytes instead of trusting the client-supplied mtype header. Declared
types outside the allowlist keep the not-allowed code; allowed
declarations whose bytes differ are rejected as mismatch. Covers SVG
by probing its root tag over leading bytes (magic never matches XML
text), TTF/OTF by magic name and WOFF/WOFF2 by four-cc.

Read the real file size from disk instead of trusting the declared
:size. Files over the limit are rejected even when the declared size
lies downwards, and small files pass even when it lies upwards.

Run the path check first everywhere so forged server paths keep the
params-validation code. Recheck from-url downloads after the write,
with a declared-only fast fail at header time. Thread the assembled
path through font validation.

Refresh the affected tests around real and sparse fixture files,
including a PNG-as-font chunked-upload rejection case.

Closes #12796

AI-assisted-by: muse-spark-1.3-contributor

* 🐛 Accept BOM-prefixed SVG uploads and cover WOFF/WOFF2/OTF/WEBP

Address review comments on #12801:

- SVG files saved with a UTF-8 BOM were rejected as
  :media-type-mismatch: read-head kept U+FEFF and the <svg probe
  never ran. A leading BOM is now stripped before the probe, and a
  generic XML sniff (application/xml, text/xml) is treated as
  "no magic evidence" for declared image/svg+xml, so the root-tag
  probe decides whether the file opens with an <svg root.
- sniff-match?/svg-file? docstrings claimed the magic database never
  matches SVG; simplemagic 1.17 does match an SVG with an XML prolog
  as image/svg+xml. Reworded to match reality.
- Added matching-pass tests for WOFF, WOFF2, OTF and WEBP (they hit
  the read-four-cc, magic-name and direct magic branches) and three
  BOM SVG regression cases.

AI-assisted-by: inkling-2-small-free
2026-11-10 15:51:48 +01:00
..
2026-09-09 17:58:09 +02:00
2026-09-29 09:07:34 +02:00
2026-09-09 17:58:09 +02:00