linux-cve-announce - CVE-2025-68237: mtdchar: fix integer overflow in read/write ioctls

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Message-ID: <2025121635-CVE-2025-68237-7f03@gregkh>
Date: Tue, 16 Dec 2025 15:08:37 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68237: mtdchar: fix integer overflow in read/write ioctls

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

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

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

mtdchar: fix integer overflow in read/write ioctls

The "req.start" and "req.len" variables are u64 values that come from the
user at the start of the function.  We mask away the high 32 bits of
"req.len" so that's capped at U32_MAX but the "req.start" variable can go
up to U64_MAX which means that the addition can still integer overflow.

Use check_add_overflow() to fix this bug.

The Linux kernel CVE team has assigned CVE-2025-68237 to this issue.


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

	Issue introduced in 5.17 with commit 6420ac0af95dbcb2fd8452e2d551ab50e1bbad83 and fixed in 6.1.159 with commit f37efdd97fd1ec3e0d0f1eec279c8279e28f981e
	Issue introduced in 5.17 with commit 6420ac0af95dbcb2fd8452e2d551ab50e1bbad83 and fixed in 6.6.118 with commit 457376c6fbf0c69326a9bf1f72416225f681192b
	Issue introduced in 5.17 with commit 6420ac0af95dbcb2fd8452e2d551ab50e1bbad83 and fixed in 6.12.60 with commit eb9361484814fb12f3b7544b33835ea67d7a6a97
	Issue introduced in 5.17 with commit 6420ac0af95dbcb2fd8452e2d551ab50e1bbad83 and fixed in 6.17.10 with commit 37944f4f8199cd153fef74e95ca268020162f212
	Issue introduced in 5.17 with commit 6420ac0af95dbcb2fd8452e2d551ab50e1bbad83 and fixed in 6.18 with commit e4185bed738da755b191aa3f2e16e8b48450e1b8

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-2025-68237
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/mtd/mtdchar.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/f37efdd97fd1ec3e0d0f1eec279c8279e28f981e
	https://git.kernel.org/stable/c/457376c6fbf0c69326a9bf1f72416225f681192b
	https://git.kernel.org/stable/c/eb9361484814fb12f3b7544b33835ea67d7a6a97
	https://git.kernel.org/stable/c/37944f4f8199cd153fef74e95ca268020162f212
	https://git.kernel.org/stable/c/e4185bed738da755b191aa3f2e16e8b48450e1b8