libhdf5 refuses to list a symbol-table group that has an entry with an
empty name (H5G__ent_to_link: "invalid link name"), so h5py cannot list
cve-2021-46244's /BAG_root. We listed it, with an object at "/BAG_root/"
(the empty name, pointing at address 0). resolve_v1_group_entries — the
listing — now fails with the new FormatError::InvalidLinkName; path
lookups still find the group's other names, as libhdf5's by-name lookup
does.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Group::datasets()/groups() (and the Mmap/Lazy handles) listed only hard
links, so a soft link to a dataset or group was missing, and dataset(name)
/ group(name) on a group handle could not open one. In old-style (symbol
table) groups a soft link's entry has no object header address, and the
listing failed outright trying to parse one.
The three facade handles each had their own copy of the child-listing
code; they now share group_v2::resolve_group_children, which returns hard
links plus soft links resolved to their targets (relative targets from
the group holding the link, via the new resolve_path_from). A dangling or
cyclic soft link, an external link and a user-defined link are left out —
h5py lists their names but cannot open them. Any other error met while
resolving is returned, not hidden.
Path resolution now walks a relative soft link's target from the group
holding it instead of rebuilding the path from the root (same result,
one less re-walk), and ignores "." components.
Regression test: soft_links_are_listed_as_their_targets (h5py writes
absolute, relative, group, dangling, cyclic and external links with
libver latest and earliest; listings compared with h5py for File,
MmapFile and LazyFile).
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Link types 65-255 are user-defined: their target is only meaningful to
the application that registered the link class. LinkMessage::parse
rejects them with InvalidLinkType, and group traversal propagated that,
so one such link made the whole group unlistable and every path through
it unresolvable (libhdf5's tall.h5 and tudlink.h5, class 187).
Group traversal (compact and dense) now leaves user-defined links out,
the way h5py leaves out links it cannot open; reserved types (2-63) are
still an error.
Regression test: user_defined_links_do_not_break_the_listing, on
libhdf5's own tools/test/testfiles tall.h5 and tudlink.h5 (BSD-style
HDF5 licence, 10 KB and 1 KB), committed as fixtures.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
- Path resolution follows soft links in both old-style (symbol table, cache
type 2) and new-style (compact and dense Link message) groups: absolute and
relative targets, links to groups, links through links, with a depth limit
so a link cycle is NestingDepthExceeded rather than a hang. A dangling link
reports the target it could not find. Previously every soft link was
PathNotFound.
- An external link is FormatError::ExternalLinkUnsupported { filename,
object_path } instead of a misleading PathNotFound.
- Message 0x0007 (External Data Files) is now a known MessageType, and a
dataset carrying it is FormatError::ExternalDataFilesUnsupported. Such a
dataset has no data address in this file, so it would otherwise be read as
"never written" and answered with fill values — wrong data, no error.
- Dense link iteration is shared between hard-link listing and the new
symbolic-link lookup; entry listing behaviour is unchanged.
- h5py interop test for both libver settings.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
