CVE-2024-50019 Information

Description

In the Linux kernel the following vulnerability has been resolved:

kthread: unpark only parked kthread

Calling into kthread unparking unconditionally is mostly harmless when the kthread is already unparked. The wake up is then simply ignored because the target is not in TASK_PARKED state.

However if the kthread is per CPU the wake up is preceded by a call to kthread_bind() which expects the task to be inactive and in TASK_PARKED state which obviously isn’t the case if it is unparked.

As a result calling kthread_stop() on an unparked per-cpu kthread triggers such a warning:

WARNING: CPU: 0 PID: 11 at kernel/kthread.c:525 __kthread_bind_mask kernel/kthread.c:525
 <TASK>
 kthread_stop+0x17a/0x630 kernel/kthread.c:707
 destroy_workqueue+0x136/0xc40 kernel/workqueue.c:5810
 wg_destruct+0x1e2/0x2e0 drivers/net/wireguard/device.c:257
 netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10693
 default_device_exit_batch+0xa14/0xa90 net/core/dev.c:11769
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:640
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Fix this with skipping unecessary unparking while stopping a kthread.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://git.kernel.org/stable/c/40a6e660d2a3a7a5cb99f0b8ff4fb41bad039f68 https://git.kernel.org/stable/c/8608196a155cb6cfae04d96b10a2652d0327e33f https://git.kernel.org/stable/c/19a5029981c87c2ad0845e713837faa88f5d8e2b https://git.kernel.org/stable/c/cda5423c1a1c906062ef235c940f249b97d9d135 https://git.kernel.org/stable/c/214e01ad4ed7158cab66498810094fac5d09b218

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5