Azure Linux 3.0 安全性更新核心 (CVE-2024-43891)
medium Nessus Plugin ID 296040
語言:
概要
遠端 Azure Linux 主機缺少一個或多個安全性更新。說明
遠端 Azure Linux 3.0 主機上安裝的核心版本比測試版舊。因此，此版本會受到 CVE-2024-43891 公告中提及的一個弱點影響。- 已解決 Linux 核心中的下列弱點：tracing: Have format file honor EVENT_FILE_FL_FREED When eventfs was introduced, special care had to be done to coordinate the freeing of the file meta data with the files that are exposed to user space. The file meta data would have a ref count that is set when the file is created and would be decremented and freed after the last user that opened the file closed it. When the file meta data was to be freed, it would set a flag (EVENT_FILE_FL_FREED) to denote that the file is freed, and any new references made (like new opens or reads) would fail as it is marked freed. This allowed other meta data to be freed after this flag was set (under the event_mutex). All the files that were dynamically created in the events directory had a pointer to the file meta data and would call event_release() when the last reference to the user space file was closed. This would be the time that it is safe to free the file meta data. A shortcut was made for the format file. It's i_private would point to the call entry directly and not point to the file's meta data. This is because all format files are the same for the same call, so it was thought there was no reason to differentiate them. The other files maintain state (like the enable, trigger, etc). But this meant if the file were to disappear, the format file would be unaware of it. This caused a race that could be trigger via the user_events test (that would create dynamic events and free them), and running a loop that would read the user_events format files: In one console run: # cd tools/testing/selftests/user_events # while true; do ./ftrace_test; done And in another console run: # cd /sys/kernel/tracing/ # while true; do cat events/user_events/__test_event/format; done 2>/dev/null With KASAN memory checking, it would trigger a use-after-free bug report (which was a real bug). This was because the format file was not checking the file's meta data flag EVENT_FILE_FL_FREED, so it would access the event that the file meta data pointed to after the event was freed. After inspection, there are other locations that were found to not check the EVENT_FILE_FL_FREED flag when accessing the trace_event_file. Add a new helper function: event_file_file() that will make sure that the event_mutex is held, and will return NULL if the trace_event_file has the EVENT_FILE_FL_FREED flag set. Have the first reference of the struct file pointer use event_file_file() and check for NULL. Later uses can still use the event_file_data() helper function if the event_mutex is still held and was not released since the event_file_file() call. (CVE-2024-43891)
請注意，Nessus 並未測試此問題，而是僅依據應用程式自我報告的版本號碼作出判斷。
解決方案
更新受影響的套件。另請參閱
Plugin 詳細資訊
嚴重性: Medium
ID: 296040
檔案名稱: azure_linux_CVE-2024-43891.nasl
版本: 1.1
類型: local
已發布: 2026/1/22
已更新: 2026/1/22
支援的感應器: Nessus
風險資訊
VPR
風險因素: Medium
分數: 4.4
CVSS v2
風險因素: Low
基本分數: 3.8
時間性分數: 2.8
媒介: CVSS2#AV:L/AC:H/Au:S/C:N/I:N/A:C
CVSS 評分資料來源: CVE-2024-43891
CVSS v3
風險因素: Medium
基本分數: 4.7
時間性分數: 4.1
媒介: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
時間媒介: CVSS:3.0/E:U/RL:O/RC:C
弱點資訊
CPE: p-cpe:/a:microsoft:azure_linux:kernel-debuginfo, p-cpe:/a:microsoft:azure_linux:kernel-devel, p-cpe:/a:microsoft:azure_linux:kernel-drivers-gpu, p-cpe:/a:microsoft:azure_linux:python3-perf, p-cpe:/a:microsoft:azure_linux:kernel-docs, x-cpe:/o:microsoft:azure_linux, p-cpe:/a:microsoft:azure_linux:kernel, p-cpe:/a:microsoft:azure_linux:kernel-drivers-sound, p-cpe:/a:microsoft:azure_linux:bpftool, p-cpe:/a:microsoft:azure_linux:kernel-drivers-accessibility, p-cpe:/a:microsoft:azure_linux:kernel-tools
必要的 KB 項目: Host/local_checks_enabled, Host/AzureLinux/release, Host/AzureLinux/rpm-list, Host/cpu
可輕鬆利用: No known exploits are available
修補程式發佈日期: 2024/10/8
弱點發布日期: 2024/8/26
參考資訊
CVE: CVE-2024-43891