CVE-2024-26814: vfio/fsl-mc: Block calling interrupt handler without trigger

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

vfio/fsl-mc: Block calling interrupt handler without trigger

The eventfd_ctx trigger pointer of the vfio_fsl_mc_irq object is
initially NULL and may become NULL if the user sets the trigger
eventfd to -1.  The interrupt handler itself is guaranteed that
trigger is always valid between request_irq() and free_irq(), but
the loopback testing mechanisms to invoke the handler function
need to test the trigger.  The triggering and setting ioctl paths
both make use of igate and are therefore mutually exclusive.

The vfio-fsl-mc driver does not make use of irqfds, nor does it
support any sort of masking operations, therefore unlike vfio-pci
and vfio-platform, the flow can remain essentially unchanged.

The Linux kernel CVE team has assigned CVE-2024-26814 to this issue.


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

	Issue introduced in 5.10 with commit cc0ee20bd969 and fixed in 6.1.84 with commit 083e750c9f5f
	Issue introduced in 5.10 with commit cc0ee20bd969 and fixed in 6.6.24 with commit ee0bd4ad780d
	Issue introduced in 5.10 with commit cc0ee20bd969 and fixed in 6.7.12 with commit de87511fb040
	Issue introduced in 5.10 with commit cc0ee20bd969 and fixed in 6.8.3 with commit 6ec0d88166da
	Issue introduced in 5.10 with commit cc0ee20bd969 and fixed in 6.9-rc1 with commit 7447d911af69

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-2024-26814
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/vfio/fsl-mc/vfio_fsl_mc_intr.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/083e750c9f5f4c3bf61161330fb84d7c8e8bb417
	https://git.kernel.org/stable/c/ee0bd4ad780dfbb60355b99f25063357ab488267
	https://git.kernel.org/stable/c/de87511fb0404d23b6da5f4660383b6ed095e28d
	https://git.kernel.org/stable/c/6ec0d88166dac43f29e96801c0927d514f17add9
	https://git.kernel.org/stable/c/7447d911af699a15f8d050dfcb7c680a86f87012