Memory Leak Affecting kernel-uki-virt-addons package, versions <0:5.14.0-503.11.1.el9_5


Severity

Recommended
0.0
medium
0
10

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.14% (35th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Memory Leak vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-ORACLE9-KERNELUKIVIRTADDONS-8391017
  • published20 Nov 2024
  • disclosed21 Aug 2024

Introduced: 21 Aug 2024

CVE-2024-43870  (opens in a new tab)
CWE-401  (opens in a new tab)

How to fix?

Upgrade Oracle:9 kernel-uki-virt-addons 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 kernel-uki-virt-addons package and not the kernel-uki-virt-addons 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 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);

&lt;IRQ&gt; perf_event_overflow() event-&gt;pending_sigtrap = pending_id; irq_work_queue(&amp;event-&gt;pending_irq); &lt;/IRQ&gt; =========&gt; PREEMPTION: TASK A -&gt; TASK B event_sched_out() event-&gt;pending_sigtrap = 0; atomic_long_inc_not_zero(&amp;event-&gt;refcount) // FAILS: task work has exited task_work_add(&amp;event-&gt;pending_task) [...] &lt;IRQ WORK&gt; perf_pending_irq() // early return: event-&gt;oncpu = -1 &lt;/IRQ WORK&gt; [...] =========&gt; TASK B -&gt; TASK A perf_event_exit_task(tsk) perf_event_exit_event() free_event() WARN(atomic_long_cmpxchg(&amp;event-&gt;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 Base Scores

version 3.1