Audited LZF, bitshuffle, bzip2 and Blosc/BloscLZ for arithmetic on
header fields and unchecked slicing. The only live bug was the Blosc
frame-size underflow fixed in the previous commit; bzip2's output-growth
step now uses a saturating subtraction as well (the allocator may hand
back more capacity than asked for).
src/test_fuzz.rs (tests only) feeds each decoder random bytes, truncated
seeds and one-to-four-edit mutations of valid frames, biased towards
edge-case u32 values in size and offset fields, and asserts no panic and
no output over the limit (tests build with overflow checks and debug
assertions). Per decoder: LZF, bzip2, bitshuffle in all six mode/block
settings plus hostile cd_values, Blosc across four codecs, three shuffles,
stored frames and a hand-built BloscLZ frame, and BloscLZ streams alone.
With the previous commit's check removed, fuzzed_frames_never_panic panics
at the same subtraction. A 100x-iteration soak (different seed) found no
other panic.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
