linux-cve-announce - CVE-2022-49303: drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event

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Message-ID: <2025022634-CVE-2022-49303-58f0@gregkh>
Date: Wed, 26 Feb 2025 03:09:37 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49303: drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle

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

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

drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle

There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below:

   (Thread 1)                |      (Thread 2)
                             | _set_timer()
rtw_joinbss_event_prehandle()|  mod_timer()
 spin_lock_bh() //(1)        |  (wait a time)
 ...                         | rtw_join_timeout_handler()
                             |  _rtw_join_timeout_handler()
 del_timer_sync()            |   spin_lock_bh() //(2)
 (wait timer to stop)        |   ...

We hold pmlmepriv->lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need pmlmepriv->lock in position (2) of thread 2.
As a result, rtw_joinbss_event_prehandle() will block forever.

This patch extracts del_timer_sync() from the protection of
spin_lock_bh(), which could let timer handler to obtain
the needed lock. What`s more, we change spin_lock_bh() to
spin_lock_irq() in _rtw_join_timeout_handler() in order to
prevent deadlock.

The Linux kernel CVE team has assigned CVE-2022-49303 to this issue.


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

	Fixed in 5.18.4 with commit 25cf414b0610fea29d8e045f315648d9007c9a46
	Fixed in 5.19 with commit 0fcddf9c7c10202946d5b19409efbdff744fba88

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-2022-49303
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/staging/r8188eu/core/rtw_mlme.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/25cf414b0610fea29d8e045f315648d9007c9a46
	https://git.kernel.org/stable/c/0fcddf9c7c10202946d5b19409efbdff744fba88