linux-cve-announce - CVE-2022-50279: wifi: rtlwifi: Fix global-out-of-bounds bug in _rtl8812ae_phy_set_txpower

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Message-ID: <2025091506-CVE-2022-50279-412b@gregkh>
Date: Mon, 15 Sep 2025 16:21:21 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50279: wifi: rtlwifi: Fix global-out-of-bounds bug in _rtl8812ae_phy_set_txpower_limit()

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

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

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

wifi: rtlwifi: Fix global-out-of-bounds bug in _rtl8812ae_phy_set_txpower_limit()

There is a global-out-of-bounds reported by KASAN:

  BUG: KASAN: global-out-of-bounds in
  _rtl8812ae_eq_n_byte.part.0+0x3d/0x84 [rtl8821ae]
  Read of size 1 at addr ffffffffa0773c43 by task NetworkManager/411

  CPU: 6 PID: 411 Comm: NetworkManager Tainted: G      D
  6.1.0-rc8+ #144 e15588508517267d37
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
  Call Trace:
   <TASK>
   ...
   kasan_report+0xbb/0x1c0
   _rtl8812ae_eq_n_byte.part.0+0x3d/0x84 [rtl8821ae]
   rtl8821ae_phy_bb_config.cold+0x346/0x641 [rtl8821ae]
   rtl8821ae_hw_init+0x1f5e/0x79b0 [rtl8821ae]
   ...
   </TASK>

The root cause of the problem is that the comparison order of
"prate_section" in _rtl8812ae_phy_set_txpower_limit() is wrong. The
_rtl8812ae_eq_n_byte() is used to compare the first n bytes of the two
strings from tail to head, which causes the problem. In the
_rtl8812ae_phy_set_txpower_limit(), it was originally intended to meet
this requirement by carefully designing the comparison order.
For example, "pregulation" and "pbandwidth" are compared in order of
length from small to large, first is 3 and last is 4. However, the
comparison order of "prate_section" dose not obey such order requirement,
therefore when "prate_section" is "HT", when comparing from tail to head,
it will lead to access out of bounds in _rtl8812ae_eq_n_byte(). As
mentioned above, the _rtl8812ae_eq_n_byte() has the same function as
strcmp(), so just strcmp() is enough.

Fix it by removing _rtl8812ae_eq_n_byte() and use strcmp() barely.
Although it can be fixed by adjusting the comparison order of
"prate_section", this may cause the value of "rate_section" to not be
from 0 to 5. In addition, commit "21e4b0726dc6" not only moved driver
from staging to regular tree, but also added setting txpower limit
function during the driver config phase, so the problem was introduced
by this commit.

The Linux kernel CVE team has assigned CVE-2022-50279 to this issue.

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

	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 4.19.276 with commit fc3442247716fc426bbcf62ed65e086e48a6d44f
	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 5.4.235 with commit 28ea268d95e57cdf6394a058f0d854206d478772
	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 5.10.173 with commit 1e950b9a841bc96e98ee25680d5c7aa305120be1
	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 5.15.99 with commit 0c962dcd6bf64b78eaffc09e497a2beb4e48bc32
	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 6.1.16 with commit f1fe40120de6ad4ffa8299fde035a5feba10d4fb
	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 6.2.3 with commit 057b52461dc005ecd85a3e4998913b1492ec0f72
	Issue introduced in 3.18 with commit 21e4b0726dc671c423e2dc9a85364716219c4502 and fixed in 6.3 with commit 117dbeda22ec5ea0918254d03b540ef8b8a64d53

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-2022-50279
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/net/wireless/realtek/rtlwifi/rtl8821ae/phy.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/fc3442247716fc426bbcf62ed65e086e48a6d44f
	https://git.kernel.org/stable/c/28ea268d95e57cdf6394a058f0d854206d478772
	https://git.kernel.org/stable/c/1e950b9a841bc96e98ee25680d5c7aa305120be1
	https://git.kernel.org/stable/c/0c962dcd6bf64b78eaffc09e497a2beb4e48bc32
	https://git.kernel.org/stable/c/f1fe40120de6ad4ffa8299fde035a5feba10d4fb
	https://git.kernel.org/stable/c/057b52461dc005ecd85a3e4998913b1492ec0f72
	https://git.kernel.org/stable/c/117dbeda22ec5ea0918254d03b540ef8b8a64d53