Improper Resource Shutdown or Release Affecting kernel-rt-debug-modules-internal package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (17th percentile)

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  • Snyk IDSNYK-RHEL9-KERNELRTDEBUGMODULESINTERNAL-7793105
  • published22 Aug 2024
  • disclosed21 Aug 2024

Introduced: 21 Aug 2024

CVE-2024-43870  (opens in a new tab)
CWE-404  (opens in a new tab)
First added by Snyk

How to fix?

There is no fixed version for RHEL:9 kernel-rt-debug-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-modules-internal package and not the kernel-rt-debug-modules-internal package as distributed by RHEL. See How to fix? for RHEL:9 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.

CVSS Scores

version 3.1