osobhandClaude Opus 5.5
b3058ca46e
libhdf5 decodes the messages of a v2/v3 superblock's extension when it opens a file (H5F__super_read) and refuses the file when one does not decode. We never looked at them, so we opened cve-2020-10810 (a File Space Info message too short for the free-space manager addresses it announces) and cve-2020-10812 (a metadata cache image past the end of the file), both of which libhdf5 refuses. A file written with a metadata cache image keeps its metadata cache entries in an image block the extension points at; libhdf5 loads them over the file's own bytes before it reads any metadata (H5C__load_cache_image, H5C__reconstruct_cache_contents). In h5clear_mdc_image.h5 the root group's header exists only in the image, so every reader failed with InvalidObjectHeaderVersion(0). The new clawhdf5_format::superblock_ext module: - read_superblock_extension decodes the v1 B-tree K, File Space Info and Metadata Cache Image messages with libhdf5's checks (versions, page size 512 B .. 1 GiB, the addresses a persisting message lists, the image inside the file), with the new FormatError::InvalidSuperblockExtension; - apply_cache_image checks an image block as libhdf5 does (signature, version, recorded length, entry types, rings, ages, addresses inside the file and not repeated, flush-dependency parents) and returns the file's bytes with every entry written at its address (FormatError::InvalidCacheImage); - metadata_view does both. File, MmapFile and LazyFile (and so h5rs) call metadata_view at open and read an image file through the patched copy; the conformance probe does the same. The image's trailing checksum is not verified, as libhdf5 does not verify it. tests/fixtures/h5clear_mdc_image.h5 is libhdf5's own test file. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
clawhdf5-format
Pure-Rust HDF5 binary format parsing and writing — no C dependencies.
Features
- Zero-copy superblock, object header, and B-tree parsing
- Chunked dataset read/write with filter pipelines
no_stdsupport (disablestdfeature)- Optional parallel reads via Rayon
- SHA-256 provenance tracking
Usage
use clawhdf5_format::Superblock;
let data = std::fs::read("data.h5").unwrap();
let sb = Superblock::from_bytes(&data).unwrap();
println!("HDF5 version {}.{}", sb.version_major(), sb.version_minor());
License
MIT