linux-cve-announce - CVE-2022-50735: wifi: mt76: do not run mt76u_status

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Message-ID: <2025122421-CVE-2022-50735-2929@gregkh>
Date: Wed, 24 Dec 2025 13:26:34 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50735: wifi: mt76: do not run mt76u_status_worker if the device is not running

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

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

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

wifi: mt76: do not run mt76u_status_worker if the device is not running

Fix the following NULL pointer dereference avoiding to run
mt76u_status_worker thread if the device is not running yet.

KASAN: null-ptr-deref in range
[0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 98 Comm: kworker/u2:2 Not tainted 5.14.0+ #78 Hardware
name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
Workqueue: mt76 mt76u_tx_status_data
RIP: 0010:mt76x02_mac_fill_tx_status.isra.0+0x82c/0x9e0
Code: c5 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 85 94 01 00 00
48 b8 00 00 00 00 00 fc ff df 4d 8b 34 24 4c 89 f2 48 c1 ea 03 <0f>
b6
04 02 84 c0 74 08 3c 03 0f 8e 89 01 00 00 41 8b 16 41 0f b7
RSP: 0018:ffffc900005af988 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffc900005afae8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff832fc661 RDI: ffffc900005afc2a
RBP: ffffc900005afae0 R08: 0000000000000001 R09: fffff520000b5f3c
R10: 0000000000000003 R11: fffff520000b5f3b R12: ffff88810b6132d8
R13: 000000000000ffff R14: 0000000000000000 R15: ffffc900005afc28
FS:  0000000000000000(0000) GS:ffff88811aa00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa0eda6a000 CR3: 0000000118f17000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
 mt76x02_send_tx_status+0x1d2/0xeb0
 mt76x02_tx_status_data+0x8e/0xd0
 mt76u_tx_status_data+0xe1/0x240
 process_one_work+0x92b/0x1460
 worker_thread+0x95/0xe00
 kthread+0x3a1/0x480
 ret_from_fork+0x1f/0x30
Modules linked in:
--[ end trace 8df5d20fc5040f65 ]--
RIP: 0010:mt76x02_mac_fill_tx_status.isra.0+0x82c/0x9e0
Code: c5 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 85 94 01 00 00
48 b8 00 00 00 00 00 fc ff df 4d 8b 34 24 4c 89 f2 48 c1 ea 03 <0f>
b6
04 02 84 c0 74 08 3c 03 0f 8e 89 01 00 00 41 8b 16 41 0f b7
RSP: 0018:ffffc900005af988 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffc900005afae8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff832fc661 RDI: ffffc900005afc2a
RBP: ffffc900005afae0 R08: 0000000000000001 R09: fffff520000b5f3c
R10: 0000000000000003 R11: fffff520000b5f3b R12: ffff88810b6132d8
R13: 000000000000ffff R14: 0000000000000000 R15: ffffc900005afc28
FS:  0000000000000000(0000) GS:ffff88811aa00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa0eda6a000 CR3: 0000000118f17000 CR4: 0000000000750ef0
PKRU: 55555554

Moreover move stat_work schedule out of the for loop.

The Linux kernel CVE team has assigned CVE-2022-50735 to this issue.


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

	Fixed in 5.15.86 with commit 69346de0eb956fb92949b9473de4647d9c34a54f
	Fixed in 6.0.16 with commit 58fdd84a89b121b761dbfb8a196356e007376ca4
	Fixed in 6.1.2 with commit f5ac749a0b21beee55d87d0b05de36976b22dff9
	Fixed in 6.2 with commit bd5dac7ced5a7c9faa4dc468ac9560c3256df845

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-2022-50735
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/mediatek/mt76/usb.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/69346de0eb956fb92949b9473de4647d9c34a54f
	https://git.kernel.org/stable/c/58fdd84a89b121b761dbfb8a196356e007376ca4
	https://git.kernel.org/stable/c/f5ac749a0b21beee55d87d0b05de36976b22dff9
	https://git.kernel.org/stable/c/bd5dac7ced5a7c9faa4dc468ac9560c3256df845