Subject: CVE-2024-42253: gpio: pca953x: fix pca953x_irq_bus_sync_unlock race

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

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

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

gpio: pca953x: fix pca953x_irq_bus_sync_unlock race

Ensure that `i2c_lock' is held when setting interrupt latch and mask in
pca953x_irq_bus_sync_unlock() in order to avoid races.

The other (non-probe) call site pca953x_gpio_set_multiple() ensures the
lock is held before calling pca953x_write_regs().

The problem occurred when a request raced against irq_bus_sync_unlock()
approximately once per thousand reboots on an i.MX8MP based system.

 * Normal case

   0-0022: write register AI|3a {03,02,00,00,01} Input latch P0
   0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0
   0-0022: write register AI|08 {ff,00,00,00,00} Output P3
   0-0022: write register AI|12 {fc,00,00,00,00} Config P3

 * Race case

   0-0022: write register AI|08 {ff,00,00,00,00} Output P3
   0-0022: write register AI|08 {03,02,00,00,01} *** Wrong register ***
   0-0022: write register AI|12 {fc,00,00,00,00} Config P3
   0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0

The Linux kernel CVE team has assigned CVE-2024-42253 to this issue.

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

	Fixed in 6.1.101 with commit 58a5c93bd1a6
	Fixed in 6.6.42 with commit e2ecdddca80d
	Fixed in 6.9.11 with commit de7cffa53149
	Fixed in 6.10 with commit bfc6444b57dc

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-2024-42253
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/gpio/gpio-pca953x.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/58a5c93bd1a6e949267400080f07e57ffe05ec34
	https://git.kernel.org/stable/c/e2ecdddca80dd845df42376e4b0197fe97018ba2
	https://git.kernel.org/stable/c/de7cffa53149c7b48bd1bb29b02390c9f05b7f41
	https://git.kernel.org/stable/c/bfc6444b57dc7186b6acc964705d7516cbaf3904