UBUNTU-CVE-2024-36961
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+
02 / AFFECTED SOFTWARE
Affected packages
50 explicit affected versions
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1 explicit affected versions
7 explicit affected versions
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23 explicit affected versions
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26 explicit affected versions
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13 explicit affected versions
9 explicit affected versions
16 explicit affected versions
10 explicit affected versions
3 explicit affected versions
51 explicit affected versions
7 explicit affected versions
12 explicit affected versions
27 explicit affected versions
3 explicit affected versions
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5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
6 explicit affected versions
13 explicit affected versions
7 explicit affected versions
10 explicit affected versions
12 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
37 explicit affected versions
10 explicit affected versions
38 explicit affected versions
9 explicit affected versions
11 explicit affected versions
2 explicit affected versions
7 explicit affected versions
4 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
5 explicit affected versions
14 explicit affected versions
4 explicit affected versions
1 explicit affected versions
3 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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+
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/c7f7c37271787a7f77d7eedc132b0b419a76b4c8
- https://git.kernel.org/stable/c/6c57bdd0505422d5ccd2df541d993aec978c842e
- https://git.kernel.org/stable/c/c7f7c37271787a7f77d7eedc132b0b419a76b4c8
- https://ubuntu.com/security/CVE-2024-36961
- https://ubuntu.com/security/notices/USN-6949-1
- https://ubuntu.com/security/notices/USN-6949-2
- https://ubuntu.com/security/notices/USN-6952-1
- https://ubuntu.com/security/notices/USN-6952-2
- https://ubuntu.com/security/notices/USN-6955-1
- https://www.cve.org/CVERecord?id=CVE-2024-36961