linux-cve-announce - CVE-2022-49980: USB: gadget: Fix use-after-free Read in usb_udc

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Message-ID: <2025061820-CVE-2022-49980-982c@gregkh>
Date: Wed, 18 Jun 2025 13:00:45 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-49980: USB: gadget: Fix use-after-free Read in usb_udc_uevent()

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

USB: gadget: Fix use-after-free Read in usb_udc_uevent()

The syzbot fuzzer found a race between uevent callbacks and gadget
driver unregistration that can cause a use-after-free bug:

---------------------------------------------------------------
BUG: KASAN: use-after-free in usb_udc_uevent+0x11f/0x130
drivers/usb/gadget/udc/core.c:1732
Read of size 8 at addr ffff888078ce2050 by task udevd/2968

CPU: 1 PID: 2968 Comm: udevd Not tainted 5.19.0-rc4-next-20220628-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
06/29/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
 kasan_report+0xbe/0x1f0 mm/kasan/report.c:495
 usb_udc_uevent+0x11f/0x130 drivers/usb/gadget/udc/core.c:1732
 dev_uevent+0x290/0x770 drivers/base/core.c:2424
---------------------------------------------------------------

The bug occurs because usb_udc_uevent() dereferences udc->driver but
does so without acquiring the udc_lock mutex, which protects this
field.  If the gadget driver is unbound from the udc concurrently with
uevent processing, the driver structure may be accessed after it has
been deallocated.

To prevent the race, we make sure that the routine holds the mutex
around the racing accesses.

The Linux kernel CVE team has assigned CVE-2022-49980 to this issue.


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

	Fixed in 5.19.7 with commit f44b0b95d50fffeca036e1ba36770390e0b519dd
	Fixed in 6.0 with commit 2191c00855b03aa59c20e698be713d952d51fc18

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-2022-49980
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/gadget/udc/core.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/f44b0b95d50fffeca036e1ba36770390e0b519dd
	https://git.kernel.org/stable/c/2191c00855b03aa59c20e698be713d952d51fc18