Message-ID: <2025100434-CVE-2023-53612-b146@gregkh>
Date: Sat,  4 Oct 2025 17:52:06 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53612: hwmon: (coretemp) Simplify platform device handling

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

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

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

hwmon: (coretemp) Simplify platform device handling

Coretemp's platform driver is unconventional. All the real work is done
globally by the initcall and CPU hotplug notifiers, while the "driver"
effectively just wraps an allocation and the registration of the hwmon
interface in a long-winded round-trip through the driver core.  The whole
logic of dynamically creating and destroying platform devices to bring
the interfaces up and down is error prone, since it assumes
platform_device_add() will synchronously bind the driver and set drvdata
before it returns, thus results in a NULL dereference if drivers_autoprobe
is turned off for the platform bus. Furthermore, the unusual approach of
doing that from within a CPU hotplug notifier, already commented in the
code that it deadlocks suspend, also causes lockdep issues for other
drivers or subsystems which may want to legitimately register a CPU
hotplug notifier from a platform bus notifier.

All of these issues can be solved by ripping this unusual behaviour out
completely, simply tying the platform devices to the lifetime of the
module itself, and directly managing the hwmon interfaces from the
hotplug notifiers. There is a slight user-visible change in that
/sys/bus/platform/drivers/coretemp will no longer appear, and
/sys/devices/platform/coretemp.n will remain present if package n is
hotplugged off, but hwmon users should really only be looking for the
presence of the hwmon interfaces, whose behaviour remains unchanged.

The Linux kernel CVE team has assigned CVE-2023-53612 to this issue.


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

	Fixed in 5.4.235 with commit 4000384684f612b3645a944f6acde0e65ac370b8
	Fixed in 5.10.173 with commit 5735878a7b7db7e9ce731cb36cec298a9de67549
	Fixed in 5.15.99 with commit 52ea47a0ddfbc5fe05e873d3f5a59db4ba3e03fe
	Fixed in 6.1.16 with commit 8fcdbc4bc01365f4b10fed7db544a3149e3054fd
	Fixed in 6.2.3 with commit c57a8d14d7880521150ee801d53a0a64fdffd9c8
	Fixed in 6.3 with commit 6d03bbff456befeccdd4d663177c4d6c75d0c4ff

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-2023-53612
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/hwmon/coretemp.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/4000384684f612b3645a944f6acde0e65ac370b8
	https://git.kernel.org/stable/c/5735878a7b7db7e9ce731cb36cec298a9de67549
	https://git.kernel.org/stable/c/52ea47a0ddfbc5fe05e873d3f5a59db4ba3e03fe
	https://git.kernel.org/stable/c/8fcdbc4bc01365f4b10fed7db544a3149e3054fd
	https://git.kernel.org/stable/c/c57a8d14d7880521150ee801d53a0a64fdffd9c8
	https://git.kernel.org/stable/c/6d03bbff456befeccdd4d663177c4d6c75d0c4ff

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