Subject: CVE-2024-43865: s390/fpu: Re-add exception handling in load_fpu_state()

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

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

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

s390/fpu: Re-add exception handling in load_fpu_state()

With the recent rewrite of the fpu code exception handling for the
lfpc instruction within load_fpu_state() was erroneously removed.

Add it again to prevent that loading invalid floating point register
values cause an unhandled specification exception.

The Linux kernel CVE team has assigned CVE-2024-43865 to this issue.

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

	Issue introduced in 6.9 with commit 8c09871a950a and fixed in 6.10.4 with commit 494b14138201
	Issue introduced in 6.9 with commit 8c09871a950a and fixed in 6.11 with commit 4734406c3923

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-2024-43865
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:
	arch/s390/kernel/fpu.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/494b14138201f07343e5488db6360c828fcc8cf6
	https://git.kernel.org/stable/c/4734406c39238cbeafe66f0060084caa3247ff53