linux-cve-announce - CVE-2025-38717: net: kcm: Fix race condition in kcm

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: <2025090459-CVE-2025-38717-fbf6@gregkh>
Date: Thu,  4 Sep 2025 17:33:22 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38717: net: kcm: Fix race condition in kcm_unattach()

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

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

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

net: kcm: Fix race condition in kcm_unattach()

syzbot found a race condition when kcm_unattach(psock)
and kcm_release(kcm) are executed at the same time.

kcm_unattach() is missing a check of the flag
kcm->tx_stopped before calling queue_work().

If the kcm has a reserved psock, kcm_unattach() might get executed
between cancel_work_sync() and unreserve_psock() in kcm_release(),
requeuing kcm->tx_work right before kcm gets freed in kcm_done().

Remove kcm->tx_stopped and replace it by the less
error-prone disable_work_sync().

The Linux kernel CVE team has assigned CVE-2025-38717 to this issue.


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

	Issue introduced in 4.6 with commit ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and fixed in 6.12.43 with commit c0bffbc92a1ca3960fb9cdb8e9f75a68468eb308
	Issue introduced in 4.6 with commit ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and fixed in 6.15.11 with commit 7275dc3bb8f91b23125ff3f47b6529935cf46152
	Issue introduced in 4.6 with commit ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and fixed in 6.16.2 with commit 798733ee5d5788b12e8a52db1519abc17e826f69
	Issue introduced in 4.6 with commit ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and fixed in 6.17-rc2 with commit 52565a935213cd6a8662ddb8efe5b4219343a25d

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-2025-38717
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/net/kcm.h
	net/kcm/kcmsock.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/c0bffbc92a1ca3960fb9cdb8e9f75a68468eb308
	https://git.kernel.org/stable/c/7275dc3bb8f91b23125ff3f47b6529935cf46152
	https://git.kernel.org/stable/c/798733ee5d5788b12e8a52db1519abc17e826f69
	https://git.kernel.org/stable/c/52565a935213cd6a8662ddb8efe5b4219343a25d