platform/x86: hp-bioscfg: pass validated element count to package parsers
21Vexday Risk Score
Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.
ssvc Trackcvss 7.1epss 0.1%
probabilidad de explotación
0.1%top 97% de las CVE
explotación observada
noninguna fuente lo reporta
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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Productos afectados
Linux · LinuxReferencias
https://git.kernel.org/stable/c/400cbc3ccc88a5ad37cd85056224635ce9eba018https://git.kernel.org/stable/c/436017808c7cbcdb5e49b2142090d4391e3de9a6https://git.kernel.org/stable/c/467e53f231f77a1677191b8cdabdaf1448439d55https://git.kernel.org/stable/c/a38127df99ae8b1851560b35b837c9952416143ahttps://git.kernel.org/stable/c/e0ddfd77c0c320b7d12b6c9169303b140b798775