Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: platform/x86: hp-bioscfg: pass validated element count to package parsers The per-type package parsers are handed the wrong element count. hp_init_bios_package_attribute() validates obj->package.count and then calls one of the five hp_populate_*_package_data() wrappers (string, integer, enumeration, ordered list, password). Each wrapper forwards a count to its hp_populate_*_elements_from_package() parser, but instead of forwarding the validated obj->package.count it derives the count from elements[0]. elements[0] is the NAME field and is always an ACPI_TYPE_STRING, so reading ->package.count from it in fact reads ->string.length through the union acpi_object. The parsers thus bound themselves against the length of the name string rather than against the real number of elements in the package. This is safe today because hp_init_bios_package_attribute() refuses any package that has fewer than the type's element count, so a parser only ever runs on a full package and never reads past it regardless of the bogus bound. An upcoming change relaxes that check to accept shorter packages. Once a parser can receive fewer elements than its per-type count, a bound taken from the name length no longer reflects the array size, and the "elem < count" loop conditions and "elem + n >= count" sub-loop guards read past the end of elements[] - an out-of-bounds heap read. Forward the validated obj->package.count to every *_package_data() wrapper so the parsers bound themselves against the real package size. This does not change behaviour for the packages that enumerate correctly today and is a prerequisite for accepting shorter packages safely.

Affected versions

Linux: a34fc329b1895fc8a6eb12099adc47009421ba6a through before 436017808c7cbcdb5e49b2142090d4391e3de9a6 (git); a34fc329b1895fc8a6eb12099adc47009421ba6a through before a38127df99ae8b1851560b35b837c9952416143a (git); a34fc329b1895fc8a6eb12099adc47009421ba6a through before 400cbc3ccc88a5ad37cd85056224635ce9eba018 (git); a34fc329b1895fc8a6eb12099adc47009421ba6a through before e0ddfd77c0c320b7d12b6c9169303b140b798775 (git); 6.6 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.