Subject: CVE-2024-50061: i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

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

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

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

i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

In the cdns_i3c_master_probe function, &master->hj_work is bound with
cdns_i3c_master_hj. And cdns_i3c_master_interrupt can call
cnds_i3c_master_demux_ibis function to start the work.

If we remove the module which will call cdns_i3c_master_remove to
make cleanup, it will free master->base through i3c_master_unregister
while the work mentioned above will be used. The sequence of operations
that may lead to a UAF bug is as follows:

CPU0                                      CPU1

                                     | cdns_i3c_master_hj
cdns_i3c_master_remove               |
i3c_master_unregister(&master->base) |
device_unregister(&master->dev)      |
device_release                       |
//free master->base                  |
                                     | i3c_master_do_daa(&master->base)
                                     | //use master->base

Fix it by ensuring that the work is canceled before proceeding with
the cleanup in cdns_i3c_master_remove.

The Linux kernel CVE team has assigned CVE-2024-50061 to this issue.

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

	Fixed in 6.6.57 with commit ea0256e393e0
	Fixed in 6.11.4 with commit 687016d6a1ef
	Fixed in 6.12-rc1 with commit 609366e7a06d

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-2024-50061
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/i3c/master/i3c-master-cdns.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/ea0256e393e0072e8c80fd941547807f0c28108b
	https://git.kernel.org/stable/c/687016d6a1efbfacdd2af913e2108de6b75a28d5
	https://git.kernel.org/stable/c/609366e7a06d035990df78f1562291c3bf0d4a12