linux-cve-announce - CVE-2025-21840: thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025030707-CVE-2025-21840-096c@gregkh>
Date: Fri,  7 Mar 2025 10:10:10 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2025-21840: thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header

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

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

thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header

The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY
attribute to receive HFI events from kernel space, encounters a
segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the
commands and the events for the thresholds").

The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value
was changed while intel_lpmd still uses the old value.

Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and
use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit
itself is questionable.

The commit introduced a new element in the middle of enum thermal_genl_attr,
which affects many existing attributes and introduces potential risks
and unnecessary maintenance burdens for userspace thermal netlink event
users.

Solve the issue by moving the newly introduced
THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the
enum thermal_genl_attr. This ensures that all existing thermal generic
netlink attributes remain unaffected.

[ rjw: Subject edits ]

The Linux kernel CVE team has assigned CVE-2025-21840 to this issue.

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

	Issue introduced in 6.13 with commit 1773572863c43a14a3e45f0591f28b7dec1ee52a and fixed in 6.13.4 with commit 3a4ca365c51729143a2cab693cd40fe0bb585ef0
	Issue introduced in 6.13 with commit 1773572863c43a14a3e45f0591f28b7dec1ee52a and fixed in 6.14-rc3 with commit c195b9c6ab9c383d7aa3f4a65879b3ca90cb378b

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-2025-21840
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:
	include/uapi/linux/thermal.h

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/3a4ca365c51729143a2cab693cd40fe0bb585ef0
	https://git.kernel.org/stable/c/c195b9c6ab9c383d7aa3f4a65879b3ca90cb378b