| 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-2025-21840: thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header |
| |
| The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY |
| attribute to receive HFI events from kernel space, encounters a |
| segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the |
| commands and the events for the thresholds"). |
| |
| The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value |
| was changed while intel_lpmd still uses the old value. |
| |
| Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and |
| use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit |
| itself is questionable. |
| |
| The commit introduced a new element in the middle of enum thermal_genl_attr, |
| which affects many existing attributes and introduces potential risks |
| and unnecessary maintenance burdens for userspace thermal netlink event |
| users. |
| |
| Solve the issue by moving the newly introduced |
| THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the |
| enum thermal_genl_attr. This ensures that all existing thermal generic |
| netlink attributes remain unaffected. |
| |
| [ rjw: Subject edits ] |
| |
| The Linux kernel CVE team has assigned CVE-2025-21840 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.13 with commit 1773572863c43a14a3e45f0591f28b7dec1ee52a and fixed in 6.13.4 with commit 3a4ca365c51729143a2cab693cd40fe0bb585ef0 |
| Issue introduced in 6.13 with commit 1773572863c43a14a3e45f0591f28b7dec1ee52a and fixed in 6.14 with commit c195b9c6ab9c383d7aa3f4a65879b3ca90cb378b |
| |
| 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-2025-21840 |
| 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: |
| include/uapi/linux/thermal.h |
| |
| |
| 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/3a4ca365c51729143a2cab693cd40fe0bb585ef0 |
| https://git.kernel.org/stable/c/c195b9c6ab9c383d7aa3f4a65879b3ca90cb378b |
