Files
pdfcraft/crates/render
cyfung1031andClaude Opus 5.5 3fc8108a07 M2.6: simple-font /Widths: bounded allocation, bad entries skipped, font kept (#276)
The vendored hayro-interpret reads /FirstChar, /LastChar and /Widths of
every simple font (TrueType, Type 1, Type 3, standard 14) in read_widths.
Three defects there, each checked against MuPDF, Poppler, PDFium and
pdf.js on synthetic files:

- One entry was pushed per code below /FirstChar before any width was
  read. 50,000,000 already took 276 MB; 4294967295 asks for 34 GB, and
  a larger value aborts on allocation (AGENTS.md §4: cap allocations
  sized by the file). Simple-font codes are single bytes, so only codes
  0 to 255 now get an entry.
- An entry that isn't a number (null, a name) ended the array, so every
  later code lost its width and glyphs piled up. It now leaves just that
  code missing (/MissingWidth); the four renderers do the same.
- A /LastChar below /FirstChar, or a /FirstChar so large the count
  overflowed, made read_widths fail, so the font didn't load and a
  standard font stood in for the embedded program. The font now loads
  with no widths from the array; the four renderers keep the font too.

Valid /Widths read exactly as before, including explicit zero widths,
which all four renderers and Apple Quartz (sips) honour literally.

Tests (a Type 3 font, so no font program is needed):
raster::tests::malformed_simple_font_widths_keep_later_widths_and_the_font
fails on main for [null 600], [/W 600], /LastChar < /FirstChar and
/FirstChar 4294967295; raster::tests::huge_simple_font_first_char_terminates
renders /FirstChar 4294967295 /LastChar 4294967295 quickly (not run
against the old code: it would exhaust memory). Vendored patch (14).

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-08 09:45:55 -04:00
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