Subject: CVE-2024-36931: s390/cio: Ensure the copied buf is NUL terminated

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

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

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

s390/cio: Ensure the copied buf is NUL terminated

Currently, we allocate a lbuf-sized kernel buffer and copy lbuf from
userspace to that buffer. Later, we use scanf on this buffer but we don't
ensure that the string is terminated inside the buffer, this can lead to
OOB read when using scanf. Fix this issue by using memdup_user_nul instead.

The Linux kernel CVE team has assigned CVE-2024-36931 to this issue.

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

	Issue introduced in 5.13 with commit a4f17cc72671 and fixed in 5.15.159 with commit c9d48ce16330
	Issue introduced in 5.13 with commit a4f17cc72671 and fixed in 6.1.91 with commit 10452edd175f
	Issue introduced in 5.13 with commit a4f17cc72671 and fixed in 6.6.31 with commit 84b38f488366
	Issue introduced in 5.13 with commit a4f17cc72671 and fixed in 6.8.10 with commit 06759ebaf75c
	Issue introduced in 5.13 with commit a4f17cc72671 and fixed in 6.9 with commit da7c622cddd4

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-2024-36931
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/s390/cio/cio_inject.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/c9d48ce163305595ae20aee27774192476d5e6a5
	https://git.kernel.org/stable/c/10452edd175fcc4fd0f5ac782ed2a002e3e5d65c
	https://git.kernel.org/stable/c/84b38f48836662c4bfae646c014f4e981e16a2b2
	https://git.kernel.org/stable/c/06759ebaf75c19c87b2453a5e130e9e61e9b5d65
	https://git.kernel.org/stable/c/da7c622cddd4fe36be69ca61e8c42e43cde94784