linux-cve-announce - CVE-2026-23167: nfc: nci: Fix race between rfkill and nci_unregister

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <2026021420-CVE-2026-23167-1892@gregkh>
Date: Sat, 14 Feb 2026 17:04:33 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2026-23167: nfc: nci: Fix race between rfkill and nci_unregister_device().

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

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

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

nfc: nci: Fix race between rfkill and nci_unregister_device().

syzbot reported the splat below [0] without a repro.

It indicates that struct nci_dev.cmd_wq had been destroyed before
nci_close_device() was called via rfkill.

nci_dev.cmd_wq is only destroyed in nci_unregister_device(), which
(I think) was called from virtual_ncidev_close() when syzbot close()d
an fd of virtual_ncidev.

The problem is that nci_unregister_device() destroys nci_dev.cmd_wq
first and then calls nfc_unregister_device(), which removes the
device from rfkill by rfkill_unregister().

So, the device is still visible via rfkill even after nci_dev.cmd_wq
is destroyed.

Let's unregister the device from rfkill first in nci_unregister_device().

Note that we cannot call nfc_unregister_device() before
nci_close_device() because

  1) nfc_unregister_device() calls device_del() which frees
     all memory allocated by devm_kzalloc() and linked to
     ndev->conn_info_list

  2) nci_rx_work() could try to queue nci_conn_info to
     ndev->conn_info_list which could be leaked

Thus, nfc_unregister_device() is split into two functions so we
can remove rfkill interfaces only before nci_close_device().

[0]:
DEBUG_LOCKS_WARN_ON(1)
WARNING: kernel/locking/lockdep.c:238 at hlock_class kernel/locking/lockdep.c:238 [inline], CPU#0: syz.0.8675/6349
WARNING: kernel/locking/lockdep.c:238 at check_wait_context kernel/locking/lockdep.c:4854 [inline], CPU#0: syz.0.8675/6349
WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x39d/0x2cf0 kernel/locking/lockdep.c:5187, CPU#0: syz.0.8675/6349
Modules linked in:
CPU: 0 UID: 0 PID: 6349 Comm: syz.0.8675 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4854 [inline]
RIP: 0010:__lock_acquire+0x3a4/0x2cf0 kernel/locking/lockdep.c:5187
Code: 18 00 4c 8b 74 24 08 75 27 90 e8 17 f2 fc 02 85 c0 74 1c 83 3d 50 e0 4e 0e 00 75 13 48 8d 3d 43 f7 51 0e 48 c7 c6 8b 3a de 8d <67> 48 0f b9 3a 90 31 c0 0f b6 98 c4 00 00 00 41 8b 45 20 25 ff 1f
RSP: 0018:ffffc9000c767680 EFLAGS: 00010046
RAX: 0000000000000001 RBX: 0000000000040000 RCX: 0000000000080000
RDX: ffffc90013080000 RSI: ffffffff8dde3a8b RDI: ffffffff8ff24ca0
RBP: 0000000000000003 R08: ffffffff8fef35a3 R09: 1ffffffff1fde6b4
R10: dffffc0000000000 R11: fffffbfff1fde6b5 R12: 00000000000012a2
R13: ffff888030338ba8 R14: ffff888030338000 R15: ffff888030338b30
FS:  00007fa5995f66c0(0000) GS:ffff8881256f8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e72f842d0 CR3: 00000000485a0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:3940
 __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:3982
 nci_close_device+0x302/0x630 net/nfc/nci/core.c:567
 nci_dev_down+0x3b/0x50 net/nfc/nci/core.c:639
 nfc_dev_down+0x152/0x290 net/nfc/core.c:161
 nfc_rfkill_set_block+0x2d/0x100 net/nfc/core.c:179
 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346
 rfkill_fop_write+0x461/0x5a0 net/rfkill/core.c:1301
 vfs_write+0x29a/0xb90 fs/read_write.c:684
 ksys_write+0x150/0x270 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa59b39acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa5995f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa59b615fa0 RCX: 00007fa59b39acb9
RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000007
RBP: 00007fa59b408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa59b616038 R14: 00007fa59b615fa0 R15: 00007ffc82218788
 </TASK>

The Linux kernel CVE team has assigned CVE-2026-23167 to this issue.


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

	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 5.10.249 with commit cd4412d5905ee580e96c48360dc98fcd9e6f3208
	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 5.15.199 with commit eaa5da5130deda26420273d4610cf6e4f794ed75
	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 6.1.162 with commit 8ea4d96419fb20f15a52ce657d49f1e7c91eb7ac
	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 6.6.123 with commit 546eba0b10989de9ccc7fd619e874a30561e2b88
	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 6.12.69 with commit 126cd30cad37bc7c2c85fe2df2a522d4edf0a5c5
	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 6.18.9 with commit c3369fc5e6120a72169e71acd72e987907a682af
	Issue introduced in 3.2 with commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and fixed in 6.19 with commit d2492688bb9fed6ab6e313682c387ae71a66ebae

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-2026-23167
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:
	include/net/nfc/nfc.h
	net/nfc/core.c
	net/nfc/nci/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/cd4412d5905ee580e96c48360dc98fcd9e6f3208
	https://git.kernel.org/stable/c/eaa5da5130deda26420273d4610cf6e4f794ed75
	https://git.kernel.org/stable/c/8ea4d96419fb20f15a52ce657d49f1e7c91eb7ac
	https://git.kernel.org/stable/c/546eba0b10989de9ccc7fd619e874a30561e2b88
	https://git.kernel.org/stable/c/126cd30cad37bc7c2c85fe2df2a522d4edf0a5c5
	https://git.kernel.org/stable/c/c3369fc5e6120a72169e71acd72e987907a682af
	https://git.kernel.org/stable/c/d2492688bb9fed6ab6e313682c387ae71a66ebae