CVE-2022-48696: regmap: spi: Reserve space for register address/padding

CVE-2022-48696: regmap: spi: Reserve space for register address/padding

[Greg Kroah-Hartman]

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

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

regmap: spi: Reserve space for register address/padding

Currently the max_raw_read and max_raw_write limits in regmap_spi struct
do not take into account the additional size of the transmitted register
address and padding.  This may result in exceeding the maximum permitted
SPI message size, which could cause undefined behaviour, e.g. data
corruption.

Fix regmap_get_spi_bus() to properly adjust the above mentioned limits
by reserving space for the register address/padding as set in the regmap
configuration.

The Linux kernel CVE team has assigned CVE-2022-48696 to this issue.


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

	Issue introduced in 5.16 with commit f231ff38b7b2 and fixed in 5.19.9 with commit 15ff1f17847c
	Issue introduced in 5.16 with commit f231ff38b7b2 and fixed in 6.0 with commit f5723cfc0193

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-2022-48696
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/base/regmap/regmap-spi.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/15ff1f17847c19174b260bd7dd0de33edcebd45e
	https://git.kernel.org/stable/c/f5723cfc01932c7a8d5c78dbf7e067e537c91439