The Linux kernel, which is the core of many operating systems, constantly undergoes updates and patching to ensure optimal performance and security. In one such instance, a vulnerability has been resolved within the User-Mode Linux (UML) kernel. The specific component of the vulnerability is related to the User Block Driver (ubd) subsystem, referenced as CVE-2024-53184. This article details the vulnerability, explains the code snippet, as well as provides links to original references, and an overview of the exploit.
Vulnerability Description
In the Linux kernel, a vulnerability has been associated with the ubd subsystem. Specifically, the drvdata is not available in release. This issue arises when a ubd device is removed, which subsequently results in a crash. The kernel panic message indicates a "Segfault with no mm", leading to the following error message:
Kernel panic - not syncing: Segfault with no mm
CPU: PID: 17 Comm: kworker/:1 Not tainted 6.8.-rc3-00107-gba3f67c11638 #1
Workqueue: events mc_work_proc
The code snippet below demonstrates the changes made to address the vulnerability
- ubd_dev = dev->class_data;
+ ubd_dev = container_of(dev->class_data, struct ubd, dev);
kfree(ubd_dev->queue);
kfree(ubd_dev->unplug_timer.data);
blk_cleanup_queue(ubd_dev->queue);
kfree(ubd_dev->queue);
This change effectively replaces the use of drvdata with container_of() for retrieving the ubd instance.
Original References
1. Linux Kernel Git
2. NVD - CVE-2024-53184
Exploit Details
The exploit for this vulnerability is not publicly available as it was discovered and addressed internally by the Linux kernel team before any public release. As the vulnerability could potentially crash the system, it is recommended that users update their systems to the latest kernel version as soon as possible to mitigate this vulnerability.
Timeline
Published on: 12/27/2024 14:15:25 UTC
Last modified on: 01/20/2025 06:20:48 UTC