Subject: CVE-2024-35904: selinux: avoid dereference of garbage after mount failure

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

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

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

selinux: avoid dereference of garbage after mount failure

In case kern_mount() fails and returns an error pointer return in the
error branch instead of continuing and dereferencing the error pointer.

While on it drop the never read static variable selinuxfs_mount.

The Linux kernel CVE team has assigned CVE-2024-35904 to this issue.

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

	Issue introduced in 4.17 with commit 0619f0f5e36f and fixed in 6.6.26 with commit 477ed6789eb9
	Issue introduced in 4.17 with commit 0619f0f5e36f and fixed in 6.8.5 with commit 68784a5d01b8
	Issue introduced in 4.17 with commit 0619f0f5e36f and fixed in 6.9 with commit 37801a36b4d6

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-2024-35904
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:
	security/selinux/selinuxfs.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/477ed6789eb9f3f4d3568bb977f90c863c12724e
	https://git.kernel.org/stable/c/68784a5d01b8868ff85a7926676b6729715fff3c
	https://git.kernel.org/stable/c/37801a36b4d68892ce807264f784d818f8d0d39b