Subject: CVE-2024-42135: vhost_task: Handle SIGKILL by flushing work and exiting

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

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

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

vhost_task: Handle SIGKILL by flushing work and exiting

Instead of lingering until the device is closed, this has us handle
SIGKILL by:

1. marking the worker as killed so we no longer try to use it with
   new virtqueues and new flush operations.
2. setting the virtqueue to worker mapping so no new works are queued.
3. running all the exiting works.

The Linux kernel CVE team has assigned CVE-2024-42135 to this issue.

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

	Fixed in 6.6.39 with commit abe067dc3a66
	Fixed in 6.9.9 with commit dec987fe2df6
	Fixed in 6.10 with commit db5247d9bf5c

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-2024-42135
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/vhost/vhost.c
	drivers/vhost/vhost.h
	include/linux/sched/vhost_task.h
	kernel/vhost_task.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/abe067dc3a662eef7d5cddbbc41ed50a0b68b0af
	https://git.kernel.org/stable/c/dec987fe2df670827eb53b97c9552ed8dfc63ad4
	https://git.kernel.org/stable/c/db5247d9bf5c6ade9fd70b4e4897441e0269b233