linux-cve-announce - CVE-2022-49309: drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event

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Message-ID: <2025022635-CVE-2022-49309-582d@gregkh>
Date: Wed, 26 Feb 2025 03:09:43 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49309: drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback()

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

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

drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback()

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

   (Thread 1)                  |      (Thread 2)
                               | _set_timer()
rtw_surveydone_event_callback()|  mod_timer()
 spin_lock_bh() //(1)          |  (wait a time)
 ...                           | rtw_scan_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_surveydone_event_callback() 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() in
rtw_scan_timeout_handler() to spin_lock_irq(). Otherwise,
spin_lock_bh() will also cause deadlock() in timer handler.

The Linux kernel CVE team has assigned CVE-2022-49309 to this issue.


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

	Fixed in 5.15.47 with commit f89f6c3ebf69623b8ea48200bd690e9e210335a1
	Fixed in 5.17.15 with commit ce129d3efd181da5fd56f4360cc8827122afa67e
	Fixed in 5.18.4 with commit 2c41f5c341853f84b7bc2f32605d4e2782e8c279
	Fixed in 5.19 with commit cc7ad0d77b51c872d629bcd98aea463a3c4109e7

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-2022-49309
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/rtl8723bs/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/f89f6c3ebf69623b8ea48200bd690e9e210335a1
	https://git.kernel.org/stable/c/ce129d3efd181da5fd56f4360cc8827122afa67e
	https://git.kernel.org/stable/c/2c41f5c341853f84b7bc2f32605d4e2782e8c279
	https://git.kernel.org/stable/c/cc7ad0d77b51c872d629bcd98aea463a3c4109e7