Memory Leak Affecting kernel-livepatch-6_4_0-150600_10_14-rt package, versions <1-150600.1.3.1
Threat Intelligence
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Test your applications- Snyk IDSNYK-SLES156-KERNELLIVEPATCH6401506001014RT-8172944
- published10 Oct 2024
- disclosed9 Oct 2024
Introduced: 9 Oct 2024
CVE-2024-43870 (opens in a new tab)How to fix?
Upgrade SLES:15.6 kernel-livepatch-6_4_0-150600_10_14-rt to version 1-150600.1.3.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-livepatch-6_4_0-150600_10_14-rt package and not the kernel-livepatch-6_4_0-150600_10_14-rt package as distributed by SLES.
See How to fix? for SLES:15.6 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
perf: Fix event leak upon exit
When a task is scheduled out, pending sigtrap deliveries are deferred to the target task upon resume to userspace via task_work.
However failures while adding an event's callback to the task_work engine are ignored. And since the last call for events exit happen after task work is eventually closed, there is a small window during which pending sigtrap can be queued though ignored, leaking the event refcount addition such as in the following scenario:
TASK A -----do_exit() exit_task_work(tsk);
<IRQ> perf_event_overflow() event->pending_sigtrap = pending_id; irq_work_queue(&event->pending_irq); </IRQ> =========> PREEMPTION: TASK A -> TASK B event_sched_out() event->pending_sigtrap = 0; atomic_long_inc_not_zero(&event->refcount) // FAILS: task work has exited task_work_add(&event->pending_task) [...] <IRQ WORK> perf_pending_irq() // early return: event->oncpu = -1 </IRQ WORK> [...] =========> TASK B -> TASK A perf_event_exit_task(tsk) perf_event_exit_event() free_event() WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1) // leak event due to unexpected refcount == 2
As a result the event is never released while the task exits.
Fix this with appropriate task_work_add()'s error handling.
References
- https://www.suse.com/security/cve/CVE-2024-43870.html
- https://bugzilla.suse.com/1229494
- https://git.kernel.org/stable/c/05d3fd599594abf79aad4484bccb2b26e1cb0b51
- https://git.kernel.org/stable/c/2fd5ad3f310de22836cdacae919dd99d758a1f1b
- https://git.kernel.org/stable/c/3d7a63352a93bdb8a1cdf29606bf617d3ac1c22a
- https://git.kernel.org/stable/c/67fad724f1b568b356c1065d50df46e6b30eb2f7
- https://git.kernel.org/stable/c/70882d7fa74f0731492a0d493e8515a4f7131831