netfs：修复以直写模式附加到文件时的预刷新 (CVE-2024-36001)

CVE编号

CVE-2024-36001

利用情况

暂无

补丁情况

N/A

披露时间

2024-05-20

漏洞描述

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix the pre-flush when appending to a file in writethrough mode In netfs_perform_write(), when the file is marked NETFS_ICTX_WRITETHROUGH or O_*SYNC or RWF_*SYNC was specified, write-through caching is performed on a buffered file. When setting up for write-through, we flush any conflicting writes in the region and wait for the write to complete, failing if there's a write error to return. The issue arises if we're writing at or above the EOF position because we skip the flush and - more importantly - the wait. This becomes a problem if there's a partial folio at the end of the file that is being written out and we want to make a write to it too. Both the already-running write and the write we start both want to clear the writeback mark, but whoever is second causes a warning looking something like: ------------[ cut here ]------------ R=00000012: folio 11 is not under writeback WARNING: CPU: 34 PID: 654 at fs/netfs/write_collect.c:105 ... CPU: 34 PID: 654 Comm: kworker/u386:27 Tainted: G S ... ... Workqueue: events_unbound netfs_write_collection_worker ... RIP: 0010:netfs_writeback_lookup_folio Fix this by making the flush-and-wait unconditional. It will do nothing if there are no folios in the pagecache and will return quickly if there are no folios in the region specified. Further, move the WBC attachment above the flush call as the flush is going to attach a WBC and detach it again if it is not present - and since we need one anyway we might as well share it.

解决建议

建议您更新当前系统或软件至最新版，完成漏洞的修复。

参考链接
https://git.kernel.org/stable/c/5eaf23b2e81349f6614f88396dc468fda89fc0b9
https://git.kernel.org/stable/c/c97f59e276d4e93480f29a70accbd0d7273cf3f5

受影响软件情况

#	类型	厂商	产品	版本	影响面
1
	运行在以下环境
	系统	debian_10	linux	*		Up to (excluding) 4.19.304-1
	运行在以下环境
	系统	debian_11	linux	*		Up to (excluding) 5.10.216-1
	运行在以下环境
	系统	debian_12	linux	*		Up to (excluding) 6.1.90-1

CVSS3评分 N/A

• 攻击路径 N/A
• 攻击复杂度 N/A
• 权限要求 N/A
• 影响范围 N/A
• 用户交互 N/A
• 可用性 N/A
• 保密性 N/A
• 完整性 N/A

N/A

CWE-ID	漏洞类型

Exp相关链接

- avd.aliyun.com