Resource Leak Affecting kernel-rt-debug-kvm package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS7-KERNELRTDEBUGKVM-7811229
- published22 Aug 2024
- disclosed21 Aug 2024
Introduced: 21 Aug 2024
CVE-2024-43869 (opens in a new tab)How to fix?
There is no fixed version for Centos:7 kernel-rt-debug-kvm.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-kvm package and not the kernel-rt-debug-kvm package as distributed by Centos.
See How to fix? for Centos:7 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.
References
- https://access.redhat.com/security/cve/CVE-2024-43869
- https://git.kernel.org/stable/c/104e258a004037bc7dba9f6085c71dad6af57ad4
- https://git.kernel.org/stable/c/3a5465418f5fd970e86a86c7f4075be262682840
- https://git.kernel.org/stable/c/9ad46f1fef421d43cdab3a7d1744b2f43b54dae0
- https://git.kernel.org/stable/c/ed2c202dac55423a52d7e2290f2888bf08b8ee99
- https://git.kernel.org/stable/c/f34d8307a73a18de5320fcc6f40403146d061891