Subject: CVE-2024-38629: dmaengine: idxd: Avoid unnecessary destruction of file_ida

From: Greg Kroah-Hartman <[email-masked]>

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

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

dmaengine: idxd: Avoid unnecessary destruction of file_ida

file_ida is allocated during cdev open and is freed accordingly
during cdev release. This sequence is guaranteed by driver file
operations. Therefore, there is no need to destroy an already empty
file_ida when the WQ cdev is removed.

Worse, ida_free() in cdev release may happen after destruction of
file_ida per WQ cdev. This can lead to accessing an id in file_ida
after it has been destroyed, resulting in a kernel panic.

Remove ida_destroy(&file_ida) to address these issues.

The Linux kernel CVE team has assigned CVE-2024-38629 to this issue.

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

	Issue introduced in 6.4 with commit e6fd6d7e5f0f and fixed in 6.6.33 with commit 9eb15f24a0b9
	Issue introduced in 6.4 with commit e6fd6d7e5f0f and fixed in 6.9.4 with commit 15edb906211b
	Issue introduced in 6.4 with commit e6fd6d7e5f0f and fixed in 6.10 with commit 76e43fa6a456

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-2024-38629
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/dma/idxd/cdev.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/9eb15f24a0b9b017b39cde8b8c07243676b63687
	https://git.kernel.org/stable/c/15edb906211bf53e7b5574f7326ab734d6bff4f9
	https://git.kernel.org/stable/c/76e43fa6a456787bad31b8d0daeabda27351a480