A region's location, a refinement's offset, a symbol's corner, a Huffman
range line and a decoded integer of 2^31 could each overflow: a panic
wherever overflow is checked. The last four wrap, as a release build did.
Bitmap::combine saturates, which comes to the same: a side is at most
65,535, so a location that overflows is past the end of any page. What is
drawn doesn't change. Patch (12), after the numbers #5491 and #5569 take.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
Rows are charged by the symbol, so an empty class decoded its collective bitmap for nothing: 65,535
rows a class, a thousand classes a dictionary. 806 KB took 196 s. It steps over the bytes instead.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
From a review of the work count. An item with no pixels was charged a step, though reading it can take
hundreds of decisions, so a 22,515-byte PDF of refined text instances of no size stayed inside the
limit and took 730 s to render. Empty height classes and export runs weren't charged at all, and 19 KB
of them took 47 s. Each integer an item reads now costs what one takes at worst, 38, so a decision
never costs more than a pixel. A full region of 10,000 instances is 0.14% of the limit, so a real file
doesn't notice.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
From CodeRabbit on the work count.
A symbol with no rows cost no work, though it is decoded all the same, so a stream of thousands of
dictionaries of such symbols, exporting none, went uncounted. Each symbol now costs a step more than
its pixels.
A refined text instance was charged after it was decoded, so one could still be 2^28 pixels past what
was left before the decoder refused. It's charged once its size is read, before anything is allocated.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
Each JBIG2 bitmap is bounded, but nothing bounded how many a stream asks for, so a few hundred
bytes could tie up a render worker for minutes, and CodeRabbit raised the same on #5461. Measured
through pdfcraft-cli, before and after:
- one halftone segment, a 795-byte PDF: 265 s, now refused at once;
- 66 halftones over patterns 1 wide, a 3,894-byte PDF: about 330 s, now refused at once;
- about 226,000 generic regions behind nested Flate, a 923-byte PDF: unfinished at 40 s, some
88 hours by extrapolation, now 4.8 s;
- 8 dictionaries of symbols of no width, a 983-byte PDF: 81 s, now 0.7 s;
- about 1,048,000 generic regions of no width, a 34 KB PDF: unfinished at 90 s, now 2.6 s;
- an aggregated dictionary over 2^20 symbols, a 713-byte PDF: unfinished at 90 s, now 9.1 s;
- 10,000 instances of an 8192 × 8192 symbol, an 18 KB PDF: 64 s, now 3.2 s;
- 30 generic regions of no data: 48 s, now 4.7 s.
A stream may now ask for 2^30 units of work: four of the largest pages, about 6 s on data the
decoder predicts and about 17 s on data it can't, inside the viewer's 20 s watchdog. Decoding a
bitmap costs a unit a pixel and 4 a row, since a row costs time at any width. Copying one costs a
unit a word and 1 a row, so a tall thin bitmap costs its rows. Each item is charged before it is
decoded, apart from what is known only as it goes: new symbols and text instances are charged in
their loops. An aggregated symbol is charged for the symbol table it rebuilds. Past the bound the
image isn't drawn, as with the other caps, and the rest of the page is.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
Each JBIG2 bitmap was bounded on its own, but a few kilobytes could still exhaust memory:
nothing bounded what a page's segments hold for later ones, or how far one segment could
multiply them. Measured on black-box streams, peak memory before and after:
- intermediate regions, 16 in 774 bytes: 514 MiB, now 98 MiB;
- an 8 MiB symbol exported 1,200 times, a 2,989-byte PDF: killed at 8 GiB, now 79 MB;
- dictionaries of zero-width symbols: 781 MB, now 72 MB;
- dictionaries retaining their coding contexts, 1.1 MB: 2.89 GB, now 71 MB;
- 65,535 references to one dictionary, 78 KB: about 17 GB, now 6 MB;
- a halftone grid of 16,384 cells a side, 98 bytes: 1.1 GB, now 2.4 MB;
- a pattern dictionary of 65,535 patterns, 48 bytes: 539 MB, now 15 MB, and it still draws;
- a custom Huffman table behind nested Flate, a 1,297-byte PDF: killed at 8 GiB, now 278 MB,
which is mostly the decoded stream;
- 11-byte segments behind nested Flate in a stream and its globals, a 4,765-byte PDF: 5 GB, now
602 MB, which is mostly the two decoded streams;
- an Indexed image whose page header claims 2^20 a side, a 743-byte PDF: aborted asking for
137 GB, now 23 MB;
- a chain of 4,000 /JBIG2Globals streams that are JBIG2 themselves, on a 2 MiB stack: overflowed
it and aborted, now 24 MB.
So PageState counts what it stores: regions, pattern and symbol dictionaries and Huffman
tables, with bitmap headers, retained contexts and a charge per item, up to 64 MiB, two square
bitmaps of 16,384 a side. A dictionary's new and exported symbols count against what is left as they are
made, not once it is stored. A segment may refer to at most 2^20 symbols, checked before any are
collected. A halftone grid has at most 2^25 cells. A pattern dictionary keeps at most 16 MiB of
shifted copies, which only speed up drawing, and none that wouldn't fit what the page has left. A custom Huffman table has at most 2^16 lines, and a
stream with its globals at most 2^20 segments and 2^22 references, checked as they are read. A
page past the bounds on a bitmap is refused when the stream is opened, since callers size their
output from its header before the page bitmap is made. And in hayro-syntax, a /JBIG2Globals
stream that is itself JBIG2 isn't decoded: globals are raw segments, so it reads as globals that
can't be decoded.
An image past a bound isn't drawn, as with the other caps, and the rest of the page is. This
bounds memory, not time: decoding work has no total yet.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* fix(render): bound xref streams, JBIG2 referred-to counts, saved graphics states and /W2 runs
Input bounds and crash fixes in the vendored hayro crates, ported from
the snapshot craft-libs carries (storytold/craft-libs#176, #239, #241):
- hayro-syntax: an xref stream subsection must be backed by its decoded
data. All-zero /W widths and a count longer than the data are refused
before any entry is inserted; a tiny stream with a large /Size or
/Index count inserted that many entries.
- hayro-syntax: a subsection running past object number u32::MAX is
refused; start + i overflowed.
- hayro-syntax: the xref stream type field is read big-endian at its
full /W[0] width, and /W[0] over 8 bytes is refused like /W[1].
- hayro-jbig2: the long-form referred-to segment count is capped at
u16::MAX before its retention bytes are read; the 29-bit count went
straight to Vec::with_capacity (about 2 GiB) and aborted the process.
- hayro-interpret: at most 4096 saved graphics states holding at most
64 MiB together. A q past either limit is counted but not copied, and
its Q still removes the clips added since.
- hayro-interpret: a /W2 run whose first CID is past MAX_CID stops there,
as /W does; a first CID of 4294967295 discarded the whole /W2 table.
Each patch is marked in the source, has a regression test in its crate,
and is listed in vendor/README.md.
* fix(render): a binary usecmap counts against the CMap nesting limit; /W2 checks the CID first
- hayro-cmap: a binary CMap's usecmap passed its own depth to the nested
parse, so a self-referencing binary CMap recursed until the stack
overflowed. It now counts like a text usecmap (ledger hayro-cmap 2).
- hayro-interpret: the /W2 first-CID check runs before the run's metrics
are read, so an incomplete run past MAX_CID no longer discards the rest
of the table (ledger 52).
* fix(render): refuse xref-stream object numbers past i32::MAX
ObjectIdentifier stores an i32; a number between i32::MAX and u32::MAX
was cast to a negative object number (ledger hayro-syntax 26).
`cargo xtask fuzz` found a 1.1 KB page whose JBIG2 image never finished
decoding (over two minutes, flat memory). It differs from a valid file by
one byte inside a symbol dictionary's arithmetic-coded data. Past the end
of its data the arithmetic decoder keeps returning values, and two loops
in symbol.rs only move on when those values make progress:
- Export runs (6.5.10): a run of length 0 doesn't advance, and the
decoder returned 0 for ever. This was the fuzz finding.
- Height classes (6.5.5): a class whose first width is already the
end-of-class marker decodes no symbol. A read-only sweep of the crate
found this one. In a synthetic dictionary every class after the first
symbol adds 13 to the height and decodes nothing, so it only fails
when the height overflows u32, after 330 million classes (about five
seconds per image, logged); a delta of 0 would never end.
The sweep found every other loop in hayro-jbig2 bounded by a symbol,
instance or pixel cap or by the end of the data. Bounded is not cheap
everywhere: refinement bitmaps in text regions and aggregate symbols
(up to 10,000 instances of up to 2^28 pixels each) are not changed
here.
Vendored hayro-jbig2 patch (3): a valid dictionary needs at most one
height class per new symbol and `2 x symbols + 1` export runs (they
alternate, so at most one zero-length run before each symbol's). Both
loops get that budget plus `EXTRA_EMPTY_STEPS` (1024), then fail the
dictionary as invalid. Encoders don't write empty steps back to back,
so the slack only tolerates oddities.
The fuzz finding now renders in 0.2 s. Synthetic regression test in
render: two dictionaries of a few arbitrary bytes each, found by
searching for streams that decode the same way (no corpus bytes). The
height-class one is drawn as twenty images so that it stalls well past
the 20 s timeout without the patch on any machine. Each case is red
with its own budget removed and green with it.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
The app, crates, binaries, bundle id, packaging, icons, screenshots and docs are now
PdfCraft / pdfcraft (repo storytold/pdfcraft). On first launch the desktop app moves the
PrintCraft settings and crash-recovery folders to the new name, and both apps read settings
saved under the old storage key, so upgrades keep recent files, preferences and unsaved work.
The signing test fixtures keep their PrintCraft subject names (they are binary).
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
The nightly fuzz job found a JBIG2 symbol dictionary that decoded for
minutes: each bitmap side may be 65535, and up to 65535 symbols are decoded
pixel by pixel. Vendored hayro-jbig2 0.3.0 with two bounds: at most 2^28
pixels per bitmap (also the page bitmap, halftone grid and grayscale image),
and at most 2^26 symbol pixels per dictionary. The finding now finishes in
about a second. Synthetic regression test (a 65535 x 65535 page and region
behind a small /Width and /Height); the corpus sweep shows 0 regressions.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
