Subject: CVE-2024-36896: USB: core: Fix access violation during port device removal

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

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

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

USB: core: Fix access violation during port device removal

Testing with KASAN and syzkaller revealed a bug in port.c:disable_store():
usb_hub_to_struct_hub() can return NULL if the hub that the port belongs to
is concurrently removed, but the function does not check for this
possibility before dereferencing the returned value.

It turns out that the first dereference is unnecessary, since hub->intfdev
is the parent of the port device, so it can be changed easily.  Adding a
check for hub == NULL prevents further problems.

The same bug exists in the disable_show() routine, and it can be fixed the
same way.

The Linux kernel CVE team has assigned CVE-2024-36896 to this issue.

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

	Issue introduced in 6.0 with commit f061f43d7418 and fixed in 6.1.91 with commit 5f1d68ef5dda
	Issue introduced in 6.0 with commit f061f43d7418 and fixed in 6.6.31 with commit 63533549ff53
	Issue introduced in 6.0 with commit f061f43d7418 and fixed in 6.8.10 with commit 6119ef6517ce
	Issue introduced in 6.0 with commit f061f43d7418 and fixed in 6.9 with commit a4b46d450c49

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-2024-36896
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/core/port.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/5f1d68ef5ddac27c6b997adccd1c339cef1e6848
	https://git.kernel.org/stable/c/63533549ff53d24daf47c443dbd43c308afc3434
	https://git.kernel.org/stable/c/6119ef6517ce501fc548154691abdaf1f954a277
	https://git.kernel.org/stable/c/a4b46d450c49f32e9d4247b421e58083fde304ce