linux-cve-announce - CVE-2025-39795: block: avoid possible overflow for chunk_sectors check in blk_stack

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Message-ID: <2025091223-CVE-2025-39795-c418@gregkh>
Date: Fri, 12 Sep 2025 17:59:25 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-39795: block: avoid possible overflow for chunk_sectors check in blk_stack_limits()

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

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

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

block: avoid possible overflow for chunk_sectors check in blk_stack_limits()

In blk_stack_limits(), we check that the t->chunk_sectors value is a
multiple of the t->physical_block_size value.

However, by finding the chunk_sectors value in bytes, we may overflow
the unsigned int which holds chunk_sectors, so change the check to be
based on sectors.

The Linux kernel CVE team has assigned CVE-2025-39795 to this issue.


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

	Fixed in 5.10.241 with commit 418751910044649baa2b424ea31cce3fc4dcc253
	Fixed in 5.15.190 with commit 8b3ce085b52e674290cbfdd07034e7653ffbe4dc
	Fixed in 6.1.149 with commit 31f2f080898e50cbf2bae62d35f9f2a997547b38
	Fixed in 6.6.103 with commit 3b9d69f0e68aa6b0acd9791c45d445154a8c66e9
	Fixed in 6.12.43 with commit 46aa80ef49594ed7de685ecbc673b291e9a2c159
	Fixed in 6.15.11 with commit 5e276e6ff9aacf8901b9c3265c3cdd2568c9fff2
	Fixed in 6.16.2 with commit 14beeef4aafecc8a41de534e31fb5be94739392f
	Fixed in 6.17-rc1 with commit 448dfecc7ff807822ecd47a5c052acedca7d09e8

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-2025-39795
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:
	block/blk-settings.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/418751910044649baa2b424ea31cce3fc4dcc253
	https://git.kernel.org/stable/c/8b3ce085b52e674290cbfdd07034e7653ffbe4dc
	https://git.kernel.org/stable/c/31f2f080898e50cbf2bae62d35f9f2a997547b38
	https://git.kernel.org/stable/c/3b9d69f0e68aa6b0acd9791c45d445154a8c66e9
	https://git.kernel.org/stable/c/46aa80ef49594ed7de685ecbc673b291e9a2c159
	https://git.kernel.org/stable/c/5e276e6ff9aacf8901b9c3265c3cdd2568c9fff2
	https://git.kernel.org/stable/c/14beeef4aafecc8a41de534e31fb5be94739392f
	https://git.kernel.org/stable/c/448dfecc7ff807822ecd47a5c052acedca7d09e8