CVE-2023-52831 cpu/hotplug: Don't offline the last non-isolated CPU
A local attacker can crash the Linux kernel by offlining the last non-isolated CPU when isolated CPUs are configured, causing a system panic.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-52831?
CVE-2023-52831 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
cpu/hotplug: Don't offline the last non-isolated CPU
If a system has isolated CPUs via the "isolcpus=" command line parameter, then an attempt to offline the last housekeeping CPU will result in a WARN_ON() when rebuilding the scheduler domains and a subsequent panic due to and unhandled empty CPU mas in partition_sched_domains_locked().
cpuset_hotplug_workfn() rebuild_sched_domains_locked() ndoms = generate_sched_domains(&doms, &attr); cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));
Thus results in an empty CPU mask which triggers the warning and then the subsequent crash:
WARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408 Call trace: build_sched_domains+0x120c/0x1408 partition_sched_domains_locked+0x234/0x880 rebuild_sched_domains_locked+0x37c/0x798 rebuild_sched_domains+0x30/0x58 cpuset_hotplug_workfn+0x2a8/0x930
Unable to handle kernel paging request at virtual address fffe80027ab37080 partition_sched_domains_locked+0x318/0x880 rebuild_sched_domains_locked+0x37c/0x798
Aside of the resulting crash, it does not make any sense to offline the last last housekeeping CPU.
Prevent this by masking out the non-housekeeping CPUs when selecting a target CPU for initiating the CPU unplug operation via the work queue.
Weakness: CWE-617
Which versions are affected by CVE-2023-52831?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-52831?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-52831 being exploited?
There is no known exploitation of CVE-2023-52831 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-52831, DEBIAN-CVE-2023-52831, GHSA-93cv-5m73-q9h8, ROOT-OS-DEBIAN-11-CVE-2023-52831, ROOT-OS-UBUNTU-2204-CVE-2023-52831, UBUNTU-CVE-2023-52831.