Subject: CVE-2024-40921: net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state

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

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

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

net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state

Pass the already obtained vlan group pointer to br_mst_vlan_set_state()
instead of dereferencing it again. Each caller has already correctly
dereferenced it for their context. This change is required for the
following suspicious RCU dereference fix. No functional changes
intended.

The Linux kernel CVE team has assigned CVE-2024-40921 to this issue.

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

	Issue introduced in 6.1.93 with commit 8ca9a750fc71 and fixed in 6.1.95 with commit 09f4337c27f5
	Issue introduced in 6.6.33 with commit 4488617e5e99 and fixed in 6.6.35 with commit a6cc9e9a651b
	Issue introduced in 6.9.3 with commit e43dd2b1ec74 and fixed in 6.9.6 with commit d2dc02775fc0
	Issue introduced in 6.8.12 with commit a2b01e65d9ba

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-2024-40921
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:
	net/bridge/br_mst.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/09f4337c27f5bdeb8646a6db91488cc2f7d537ff
	https://git.kernel.org/stable/c/a6cc9e9a651b9861efa068c164ee62dfba68c6ca
	https://git.kernel.org/stable/c/d2dc02775fc0c4eacaee833a0637e5958884a8e5
	https://git.kernel.org/stable/c/36c92936e868601fa1f43da6758cf55805043509