| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-27006: thermal/debugfs: Add missing count increment to thermal_debug_tz_trip_up() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| thermal/debugfs: Add missing count increment to thermal_debug_tz_trip_up() |
| |
| The count field in struct trip_stats, representing the number of times |
| the zone temperature was above the trip point, needs to be incremented |
| in thermal_debug_tz_trip_up(), for two reasons. |
| |
| First, if a trip point is crossed on the way up for the first time, |
| thermal_debug_update_temp() called from update_temperature() does |
| not see it because it has not been added to trips_crossed[] array |
| in the thermal zone's struct tz_debugfs object yet. Therefore, when |
| thermal_debug_tz_trip_up() is called after that, the trip point's |
| count value is 0, and the attempt to divide by it during the average |
| temperature computation leads to a divide error which causes the kernel |
| to crash. Setting the count to 1 before the division by incrementing it |
| fixes this problem. |
| |
| Second, if a trip point is crossed on the way up, but it has been |
| crossed on the way up already before, its count value needs to be |
| incremented to make a record of the fact that the zone temperature is |
| above the trip now. Without doing that, if the mitigations applied |
| after crossing the trip cause the zone temperature to drop below its |
| threshold, the count will not be updated for this episode at all and |
| the average temperature in the trip statistics record will be somewhat |
| higher than it should be. |
| |
| Cc :6.8+ <stable@vger.kernel.org> # 6.8+ |
| |
| The Linux kernel CVE team has assigned CVE-2024-27006 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.8 with commit 7ef01f228c9f54c6260319858be138a8a7e9e704 and fixed in 6.8.8 with commit 9c8215d32e730b597c809a9d2090bf8ec1b79fcf |
| Issue introduced in 6.8 with commit 7ef01f228c9f54c6260319858be138a8a7e9e704 and fixed in 6.9 with commit b552f63cd43735048bbe9bfbb7a9dcfce166fbdd |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-27006 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/thermal/thermal_debugfs.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/9c8215d32e730b597c809a9d2090bf8ec1b79fcf |
| https://git.kernel.org/stable/c/b552f63cd43735048bbe9bfbb7a9dcfce166fbdd |
