linux-cve-announce - CVE-2022-49951: firmware_loader: Fix use-after-free during unregister

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Message-ID: <2025061810-CVE-2022-49951-bc9b@gregkh>
Date: Wed, 18 Jun 2025 13:00:16 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-49951: firmware_loader: Fix use-after-free during unregister

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

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

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

firmware_loader: Fix use-after-free during unregister

In the following code within firmware_upload_unregister(), the call to
device_unregister() could result in the dev_release function freeing the
fw_upload_priv structure before it is dereferenced for the call to
module_put(). This bug was found by the kernel test robot using
CONFIG_KASAN while running the firmware selftests.

  device_unregister(&fw_sysfs->dev);
  module_put(fw_upload_priv->module);

The problem is fixed by copying fw_upload_priv->module to a local variable
for use when calling device_unregister().

The Linux kernel CVE team has assigned CVE-2022-49951 to this issue.


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

	Issue introduced in 5.19 with commit 97730bbb242cde22b7140acd202ffd88823886c9 and fixed in 5.19.8 with commit d380d40930a674c520a5b55f3be1eb17dc634ebc
	Issue introduced in 5.19 with commit 97730bbb242cde22b7140acd202ffd88823886c9 and fixed in 6.0 with commit 8b40c38e37492b5bdf8e95b46b5cca9517a9957a

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-2022-49951
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/base/firmware_loader/sysfs_upload.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/d380d40930a674c520a5b55f3be1eb17dc634ebc
	https://git.kernel.org/stable/c/8b40c38e37492b5bdf8e95b46b5cca9517a9957a