Red Hat: CVE-2024-36961: kernel: thermal/debugfs: Fix two locking issues with thermal zone debug (Multiple Advisories)

Red Hat: CVE-2024-36961: kernel: thermal/debugfs: Fix two locking issues with thermal zone debug (Multiple Advisories)

Severity

4

CVSS

(AV:L/AC:L/Au:M/C:N/I:N/A:C)

Published

06/03/2024

Created

12/06/2024

Added

12/05/2024

Modified

12/05/2024

Description

In the Linux kernel, the following vulnerability has been resolved: thermal/debugfs: Fix two locking issues with thermal zone debug With the current thermal zone locking arrangement in the debugfs code, user space can open the "mitigations" file for a thermal zone before the zone's debugfs pointer is set which will result in a NULL pointer dereference in tze_seq_start(). Moreover, thermal_debug_tz_remove() is not called under the thermal zone lock, so it can run in parallel with the other functions accessing the thermal zone's struct thermal_debugfs object.Then, it may clear tz->debugfs after one of those functions has checked it and the struct thermal_debugfs object may be freed prematurely. To address the first problem, pass a pointer to the thermal zone's struct thermal_debugfs object to debugfs_create_file() in thermal_debug_tz_add() and make tze_seq_start(), tze_seq_next(), tze_seq_stop(), and tze_seq_show() retrieve it from s->private instead of a pointer to the thermal zone object.This will ensure that tz_debugfs will be valid across the "mitigations" file accesses until thermal_debugfs_remove_id() called by thermal_debug_tz_remove() removes that file. To address the second problem, use tz->lock in thermal_debug_tz_remove() around the tz->debugfs value check (in case the same thermal zone is removed at the same time in two different threads) and its reset to NULL. Cc :6.8+ <[email protected]> # 6.8+

Solution(s)

• redhat-upgrade-kernel
• redhat-upgrade-kernel-rt

References

• CVE-2024-36961
• RHSA-2024:9315