CVE-2026-72008: pmdomain: mediatek: Fix possible nullptr KP in HWV cleanup/on-check

CVE-2026-72008: pmdomain: mediatek: Fix possible nullptr KP in HWV cleanup/on-check

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

pmdomain: mediatek: Fix possible nullptr KP in HWV cleanup/on-check

Should probe fail for HW_VOTER type power domains, this driver was
unconditionally trying to perform cleanup for DIRECT_CTL domains,
but only after checking if the target domain is powered on... with
the DIRECT_CTL scpsys_domain_is_on() code again.

And there's more: the scpsys_domain_is_on() function is also being
unconditionally used in the probe path, for any power domain that
has flag MTK_SCPD_KEEP_DEFAULT_OFF!

This bug was never experienced by anyone because the HWV domains
never failed probe, and because none of those is declared with the
aforementioned flag - but it's still something critical.

In order to fix this, add a check for MTCMOS Type and, based on
that, call the correct functions for an "is on" check, and also
do the same for the cleanup path, calling the correct functions
for the "power off" action.

For the latter, since there's a call to pm_genpd_remove() right
before calling power_off, be cautious and add a variation of the
power off functions (with a _internal suffix) for those to get a
pointer to scpsys_domain instead of one to generic_pm_domain as,
even if that's still working, this is way too much fragile and
would break at some point.

The Linux kernel CVE team has assigned CVE-2026-72008 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.19 with commit 88914db077b6c2920b29a3ec76109a2fd3cf8d38 and fixed in 7.1.5 with commit 36c2d7728540252474752172027f0113028ab00c
	Issue introduced in 6.19 with commit 88914db077b6c2920b29a3ec76109a2fd3cf8d38 and fixed in 7.2-rc4 with commit a4876f11aa1d076802676e23f8af500706e780e3

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-72008
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/pmdomain/mediatek/mtk-pm-domains.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/36c2d7728540252474752172027f0113028ab00c
	https://git.kernel.org/stable/c/a4876f11aa1d076802676e23f8af500706e780e3