Release Date: | 2024-05-21 |
In the Linux kernel, the following vulnerability has been resolved: sched/psi: Fix use-after-free in ep_remove_wait_queue() If a non-root cgroup gets removed when there is a thread that registered trigger and is polling on a pressure file within the cgroup, the polling waitqueue gets freed in the following path: do_rmdir cgroup_rmdir kernfs_drain_open_files cgroup_file_release cgroup_pressure_release psi_trigger_destroy However, the polling thread still has a reference to the pressure file and will access the freed waitqueue when the file is closed or upon exit: fput ep_eventpoll_release ep_free ep_remove_wait_queue remove_wait_queue This results in use-after-free as pasted below. The fundamental problem here is that cgroup_file_release() (and consequently waitqueue's lifetime) is not tied to the file's real lifetime. Using wake_up_pollfree() here might be less than ideal, but it is in line with the comment at commit 42288cb44c4b ('wait: add wake_up_pollfree()') since the waitqueue's lifetime is not tied to file's one and can be considered as another special case. While this would be fixable by somehow making cgroup_file_release() be tied to the fput(), it would require sizable refactoring at cgroups or higher layer which might be more justifiable if we identify more cases like this. BUG: KASAN: use-after-free in _raw_spin_lock_irqsave+0x60/0xc0 Write of size 4 at addr ffff88810e625328 by task a.out/4404 CPU: 19 PID: 4404 Comm: a.out Not tainted 6.2.0-rc6 #38 Hardware name: Amazon EC2 c5a.8xlarge/, BIOS 1.0 10/16/2017 Call Trace:
See more information about CVE-2023-52707 from MITRE CVE dictionary and NIST NVD
NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.
Base Score: | 7 | CVSS Vector: | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
Attack Vector: | Local network | Attack Complexity: | High |
Privileges Required: | Low | User Interaction: | None |
Scope: | Unchanged | Confidentiality Impact: | High |
Integrity Impact: | High | Availability Impact: | High |
Platform | Errata | Release Date |
Oracle Linux version 8 (kernel) | ELSA-2024-5101 | 2024-08-08 |
This page is generated automatically and has not been checked for errors or omissions. For clarification or corrections: