linux-cve-announce - CVE-2022-49634: sysctl: Fix data-races in proc_dou8vec

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Message-ID: <2025022617-CVE-2022-49634-4a89@gregkh>
Date: Wed, 26 Feb 2025 03:23:17 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49634: sysctl: Fix data-races in proc_dou8vec_minmax().

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

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

sysctl: Fix data-races in proc_dou8vec_minmax().

A sysctl variable is accessed concurrently, and there is always a chance
of data-race.  So, all readers and writers need some basic protection to
avoid load/store-tearing.

This patch changes proc_dou8vec_minmax() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side.  For now,
proc_dou8vec_minmax() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.

The Linux kernel CVE team has assigned CVE-2022-49634 to this issue.

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

	Issue introduced in 5.13 with commit cb9444130662c6c13022579c861098f212db2562 and fixed in 5.15.56 with commit e58b02e445463065b4078bf621561da75197853f
	Issue introduced in 5.13 with commit cb9444130662c6c13022579c861098f212db2562 and fixed in 5.18.13 with commit 5f776daef0b5354615ec4b4234cd9539ca05f273
	Issue introduced in 5.13 with commit cb9444130662c6c13022579c861098f212db2562 and fixed in 5.19 with commit 7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18

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-2022-49634
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:
	kernel/sysctl.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/f177b382c33900d0e5a9766493c11a1074076f78
	https://git.kernel.org/stable/c/e58b02e445463065b4078bf621561da75197853f
	https://git.kernel.org/stable/c/5f776daef0b5354615ec4b4234cd9539ca05f273
	https://git.kernel.org/stable/c/7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18