CVE-2024-36932

In the Linux kernel, the following vulnerability has been resolved:

thermal/debugfs: Prevent use-after-free from occurring after cdev removal

Since thermal_debug_cdev_remove() does not run under cdev->lock, it can run in parallel with thermal_debug_cdev_state_update() and it may free the struct thermal_debugfs object used by the latter after it has been checked against NULL.

If that happens, thermal_debug_cdev_state_update() will access memory that has been freed already causing the kernel to crash.

Address this by using cdev->lock in thermal_debug_cdev_remove() around the cdev->debugfs value check (in case the same cdev is removed at the same time in two different threads) and its reset to NULL.

Cc :6.8+ stable@vger.kernel.org # 6.8+

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/c1279dee33369e2525f532364bb87207d23b9481
• https://git.kernel.org/stable/c/d351eb0ab04c3e8109895fc33250cebbce9c11da
• https://git.kernel.org/stable/c/c1279dee33369e2525f532364bb87207d23b9481
• https://git.kernel.org/stable/c/d351eb0ab04c3e8109895fc33250cebbce9c11da