- Vulnerability/
- CVE-2024-43870
CVE-2024-43870: perf: Fix event leak upon exit
First published: Wed Aug 21 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.112-1 6.11.7-1 6.11.9-1 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- 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
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-43870
- https://nvd.nist.gov/vuln/detail/CVE-2024-43870
- https://launchpad.net/bugs/cve/CVE-2024-43870
- https://security-tracker.debian.org/tracker/CVE-2024-43870
- https://ubuntu.com/security/CVE-2024-43870
- https://git.kernel.org/linus/2fd5ad3f310de22836cdacae919dd99d758a1f1b
- agent/title
- agent/severity
- agent/type
- agent/first-publish-date
- collector/nvd-api
- source/NVD
- collector/mitre-cve
- source/MITRE
- agent/last-modified-date
- collector/usn-cve
- source/Ubuntu
- collector/nvd-cve
- collector/security-tracker-debian
- source/Debian
- agent/software-canonical-lookup
- agent/references
- agent/author
- agent/softwarecombine
- agent/tags
- agent/description
- agent/event
- package-manager/debian