Subject: CVE-2024-26995: usb: typec: tcpm: Correct the PDO counting in pd_set

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

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

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

usb: typec: tcpm: Correct the PDO counting in pd_set

Off-by-one errors happen because nr_snk_pdo and nr_src_pdo are
incorrectly added one. The index of the loop is equal to the number of
PDOs to be updated when leaving the loop and it doesn't need to be added
one.

When doing the power negotiation, TCPM relies on the "nr_snk_pdo" as
the size of the local sink PDO array to match the Source capabilities
of the partner port. If the off-by-one overflow occurs, a wrong RDO
might be sent and unexpected power transfer might happen such as over
voltage or over current (than expected).

"nr_src_pdo" is used to set the Rp level when the port is in Source
role. It is also the array size of the local Source capabilities when
filling up the buffer which will be sent as the Source PDOs (such as
in Power Negotiation). If the off-by-one overflow occurs, a wrong Rp
level might be set and wrong Source PDOs will be sent to the partner
port. This could potentially cause over current or port resets.

The Linux kernel CVE team has assigned CVE-2024-26995 to this issue.

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

	Issue introduced in 6.8 with commit cd099cde4ed2 and fixed in 6.8.8 with commit f3da3192cdd3
	Issue introduced in 6.8 with commit cd099cde4ed2 and fixed in 6.9 with commit c4128304c216

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-2024-26995
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/f3da3192cdd3fefe213390e976eec424a8e270b5
	https://git.kernel.org/stable/c/c4128304c2169b4664ed6fb6200f228cead2ab70