linux-cve-announce - CVE-2025-21751: net/mlx5: HWS, change error flow on matcher disconnect

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Message-ID: <2025022601-CVE-2025-21751-101c@gregkh>
Date: Wed, 26 Feb 2025 18:11:33 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2025-21751: net/mlx5: HWS, change error flow on matcher disconnect

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

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

net/mlx5: HWS, change error flow on matcher disconnect

Currently, when firmware failure occurs during matcher disconnect flow,
the error flow of the function reconnects the matcher back and returns
an error, which continues running the calling function and eventually
frees the matcher that is being disconnected.
This leads to a case where we have a freed matcher on the matchers list,
which in turn leads to use-after-free and eventual crash.

This patch fixes that by not trying to reconnect the matcher back when
some FW command fails during disconnect.

Note that we're dealing here with FW error. We can't overcome this
problem. This might lead to bad steering state (e.g. wrong connection
between matchers), and will also lead to resource leakage, as it is
the case with any other error handling during resource destruction.

However, the goal here is to allow the driver to continue and not crash
the machine with use-after-free error.

The Linux kernel CVE team has assigned CVE-2025-21751 to this issue.

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

	Fixed in 6.13.3 with commit 23a86c76a1a197e8fbbbd0ce3e826eb58c471624
	Fixed in 6.14-rc1 with commit 1ce840c7a659aa53a31ef49f0271b4fd0dc10296

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-2025-21751
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/net/ethernet/mellanox/mlx5/core/steering/hws/matcher.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/23a86c76a1a197e8fbbbd0ce3e826eb58c471624
	https://git.kernel.org/stable/c/1ce840c7a659aa53a31ef49f0271b4fd0dc10296