Subject: CVE-2024-26978: serial: max310x: fix NULL pointer dereference in I2C instantiation

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

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

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

serial: max310x: fix NULL pointer dereference in I2C instantiation

When trying to instantiate a max14830 device from userspace:

    echo max14830 0x60 > /sys/bus/i2c/devices/i2c-2/new_device

we get the following error:

    Unable to handle kernel NULL pointer dereference at virtual address...
    ...
    Call trace:
        max310x_i2c_probe+0x48/0x170 [max310x]
        i2c_device_probe+0x150/0x2a0
    ...

Add check for validity of devtype to prevent the error, and abort probe
with a meaningful error message.

The Linux kernel CVE team has assigned CVE-2024-26978 to this issue.

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

	Issue introduced in 5.4.272 with commit f5c252aaa1be and fixed in 5.4.274 with commit 7d271b798add
	Issue introduced in 5.10.213 with commit 85d79478710a and fixed in 5.10.215 with commit c45e53c27b78
	Issue introduced in 6.0 with commit 2e1f2d9a9bdb and fixed in 6.1.84 with commit 12609c76b755
	Issue introduced in 6.0 with commit 2e1f2d9a9bdb and fixed in 6.6.24 with commit 2160ad6861c4
	Issue introduced in 6.0 with commit 2e1f2d9a9bdb and fixed in 6.7.12 with commit 5cd8af02b466
	Issue introduced in 6.0 with commit 2e1f2d9a9bdb and fixed in 6.8.3 with commit aeca49661fd0
	Issue introduced in 6.0 with commit 2e1f2d9a9bdb and fixed in 6.9 with commit 0d27056c24ef

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-2024-26978
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/tty/serial/max310x.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/7d271b798add90c6196539167c019d0817285cf0
	https://git.kernel.org/stable/c/c45e53c27b78afd6c81fc25608003576f27b5735
	https://git.kernel.org/stable/c/12609c76b755dbeb1645c0aacc0f0f4743b2eff3
	https://git.kernel.org/stable/c/2160ad6861c4a21d3fa553d7b2aaec6634a37f8a
	https://git.kernel.org/stable/c/5cd8af02b466e1beeae13e2de3dc58fcc7925e5a
	https://git.kernel.org/stable/c/aeca49661fd02fd56fb026768b580ce301b45733
	https://git.kernel.org/stable/c/0d27056c24efd3d63a03f3edfbcfc4827086b110