Every hang the nightly fuzz job found (11 findings, 8 source files) now
finishes in 0.1-2 s; each cause has a synthetic regression test that times
out without its fix.
- cos (7 findings, our own parser): a stream whose /Length pointed at
itself, with no endstream, made every parse attempt fail and each attempt
reload the same object: ~2^32 parses. Objects being loaded are a seen-set,
/Length values are memoised per load, and the shifted-header retry only
runs when the header is shifted.
- hayro-syntax (3): deciding where an inline image's data ends re-parsed the
rest of the stream, nesting through every inline image; 50 images ran for
over ten minutes. The look-ahead no longer nests and is bounded (256).
- hayro-interpret (1): a Type 3 glyph showing eight glyphs of its own font,
sixteen deep. Nested paints share a per-page budget (50,000).
The pdf.js corpus sweep matches its baseline (963 ok, same 20 known).
xtask check writes its report under CARGO_TARGET_DIR too.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The second full nightly fuzz run on main found two more:
- hayro-syntax computed a Flate/LZW predictor row as columns × bits in
wrapping arithmetic: /Columns 9223372036854775807 asked for 2^61 bytes and
aborted on any machine. Row widths are now saturating usize (colors × bits
also overflowed u8), a zero width is refused (it divided by zero), and a
row longer than the data is not allocated (empty output, as before).
- hayro stroked /LW 9223372036854775807 as given, and stroke expansion
allocated 10 GB. Widths are clamped to 4 × (canvas width + height) device
pixels, which covers the same pixels.
Both findings now run in 8 MB. Synthetic regression test in render.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The first full nightly fuzz run on main (now that the runner survives) found
two 4 GiB allocations, caught by the 4 GiB child cap:
- an inline stencil mask claiming /W 4294967295 was decoded in hayro-interpret
before the renderer's MAX_IMAGE_PIXELS check could skip it (locally 9.6 GB,
42 s). Vendored patch image_size_ok: images and masks over 2^28 pixels are
not decoded.
- a CCITT image whose /DecodeParms claimed /Columns 4294967295 (with a small
/Width) sized the decoder's line buffers (locally 4.3 GB). Vendored patch
ccitt_size_ok in hayro-syntax: at most 2^20 columns and 2^28 pixels.
Both findings now run in 7 MB. Synthetic regression test in render.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
