Subject: CVE-2023-52704: freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL

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

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

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

freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL

Tetsuo-San noted that commit f5d39b020809 ("freezer,sched: Rewrite
core freezer logic") broke call_usermodehelper_exec() for the KILLABLE
case.

Specifically it was missed that the second, unconditional,
wait_for_completion() was not optional and ensures the on-stack
completion is unused before going out-of-scope.

The Linux kernel CVE team has assigned CVE-2023-52704 to this issue.

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

	Issue introduced in 6.1 with commit f5d39b020809 and fixed in 6.1.13 with commit 7f9f6c54da87
	Issue introduced in 6.1 with commit f5d39b020809 and fixed in 6.2 with commit eedeb787ebb5

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-2023-52704
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:
	kernel/umh.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/7f9f6c54da876b3f0bece2b569456ceb96965ed7
	https://git.kernel.org/stable/c/eedeb787ebb53de5c5dcf7b7b39d01bf1b0f037d