Subject: CVE-2024-46691: usb: typec: ucsi: Move unregister out of atomic section

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

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

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

usb: typec: ucsi: Move unregister out of atomic section

Commit '9329933699b3 ("soc: qcom: pmic_glink: Make client-lock
non-sleeping")' moved the pmic_glink client list under a spinlock, as it
is accessed by the rpmsg/glink callback, which in turn is invoked from
IRQ context.

This means that ucsi_unregister() is now called from atomic context,
which isn't feasible as it's expecting a sleepable context. An effort is
under way to get GLINK to invoke its callbacks in a sleepable context,
but until then lets schedule the unregistration.

A side effect of this is that ucsi_unregister() can now happen
after the remote processor, and thereby the communication link with it, is
gone. pmic_glink_send() is amended with a check to avoid the resulting NULL
pointer dereference.
This does however result in the user being informed about this error by
the following entry in the kernel log:

  ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5

The Linux kernel CVE team has assigned CVE-2024-46691 to this issue.

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

	Issue introduced in 6.10 with commit 9329933699b3 and fixed in 6.10.8 with commit 095b0001aefd
	Issue introduced in 6.10 with commit 9329933699b3 and fixed in 6.11 with commit 11bb2ffb6793
	Issue introduced in 6.6.33 with commit fbadcde1572f
	Issue introduced in 6.8.12 with commit 8d62ab7d89a4
	Issue introduced in 6.9.3 with commit bd54d7c8e76d

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-2024-46691
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/soc/qcom/pmic_glink.c
	drivers/usb/typec/ucsi/ucsi_glink.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/095b0001aefddcd9361097c971b7debc84e72714
	https://git.kernel.org/stable/c/11bb2ffb679399f99041540cf662409905179e3a