CVE-2024-43869 Affecting perf package, versions <0:5.14.0-503.11.1.el9_5


Severity

Recommended
medium

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-ORACLE9-PERF-8388764
  • published20 Nov 2024
  • disclosed21 Aug 2024

Introduced: 21 Aug 2024

CVE-2024-43869  (opens in a new tab)

How to fix?

Upgrade Oracle:9 perf to version 0:5.14.0-503.11.1.el9_5 or higher.
This issue was patched in ELSA-2024-9315.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

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

perf: Fix event leak upon exec and file release

The perf pending task work is never waited upon the matching event release. In the case of a child event, released via free_event() directly, this can potentially result in a leaked event, such as in the following scenario that doesn't even require a weak IRQ work implementation to trigger:

schedule() prepare_task_switch() =======> <NMI> perf_event_overflow() event->pending_sigtrap = ... irq_work_queue(&event->pending_irq) <======= </NMI> perf_event_task_sched_out() event_sched_out() event->pending_sigtrap = 0; atomic_long_inc_not_zero(&event->refcount) task_work_add(&event->pending_task) finish_lock_switch() =======> <IRQ> perf_pending_irq() //do nothing, rely on pending task work <======= </IRQ>

begin_new_exec() perf_event_exit_task() perf_event_exit_event() // If is child event free_event() WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1) // event is leaked

Similar scenarios can also happen with perf_event_remove_on_exec() or simply against concurrent perf_event_release().

Fix this with synchonizing against the possibly remaining pending task work while freeing the event, just like is done with remaining pending IRQ work. This means that the pending task callback neither need nor should hold a reference to the event, preventing it from ever beeing freed.

CVSS Scores

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