Subject: CVE-2023-52877: usb: typec: tcpm: Fix NULL pointer dereference in tcpm_pd_svdm()

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

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

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

usb: typec: tcpm: Fix NULL pointer dereference in tcpm_pd_svdm()

It is possible that typec_register_partner() returns ERR_PTR on failure.
When port->partner is an error, a NULL pointer dereference may occur as
shown below.

[91222.095236][  T319] typec port0: failed to register partner (-17)
...
[91225.061491][  T319] Unable to handle kernel NULL pointer dereference
at virtual address 000000000000039f
[91225.274642][  T319] pc : tcpm_pd_data_request+0x310/0x13fc
[91225.274646][  T319] lr : tcpm_pd_data_request+0x298/0x13fc
[91225.308067][  T319] Call trace:
[91225.308070][  T319]  tcpm_pd_data_request+0x310/0x13fc
[91225.308073][  T319]  tcpm_pd_rx_handler+0x100/0x9e8
[91225.355900][  T319]  kthread_worker_fn+0x178/0x58c
[91225.355902][  T319]  kthread+0x150/0x200
[91225.355905][  T319]  ret_from_fork+0x10/0x30

Add a check for port->partner to avoid dereferencing a NULL pointer.

The Linux kernel CVE team has assigned CVE-2023-52877 to this issue.

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

	Issue introduced in 5.12 with commit 5e1d4c49fbc8 and fixed in 5.15.138 with commit e5f53a68a596
	Issue introduced in 5.12 with commit 5e1d4c49fbc8 and fixed in 6.1.62 with commit e7a802447c49
	Issue introduced in 5.12 with commit 5e1d4c49fbc8 and fixed in 6.5.11 with commit 9ee038590d80
	Issue introduced in 5.12 with commit 5e1d4c49fbc8 and fixed in 6.6.1 with commit b37a168c0137
	Issue introduced in 5.12 with commit 5e1d4c49fbc8 and fixed in 6.7 with commit 4987daf86c15

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-2023-52877
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/usb/typec/tcpm/tcpm.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/e5f53a68a596e04df3fde3099273435a30b6fdac
	https://git.kernel.org/stable/c/e7a802447c491903aa7cb45967aa2a934a4e63fc
	https://git.kernel.org/stable/c/9ee038590d808a95d16adf92818dcd4752273c08
	https://git.kernel.org/stable/c/b37a168c0137156042a0ca9626651b5a789e822b
	https://git.kernel.org/stable/c/4987daf86c152ff882d51572d154ad12e4ff3a4b