CVE-2023-54187

Vulnerability

Description

CVE-2023-54187 is a race condition vulnerability in the Linux kernel's F2FS (Flash-Friendly File System) implementation. The bug occurs during directory rename operations, where a race between concurrent rename and other directory operations can lead to filesystem corruption. This issue is analogous to a previously fixed vulnerability in ext4 (CVE-2023-54187 is the F2FS counterpart of the ext4 bug addressed by commit 0813299c586b) [1].

Exploitation

An attacker with local access and the ability to trigger concurrent rename operations on a directory can exploit this race condition. The attack requires no special privileges beyond the ability to perform file operations on the F2FS filesystem. The race window exists when the kernel's VFS layer of directory entry manipulation is not properly serialized, allowing a rename to proceed while another operation modifies the same directory structure [2].

Impact

Successful exploitation can cause directory corruption, potentially leading to data loss or filesystem inconsistency. In the worst case, this could result in a denial of service or, if the corruption affects critical system directories, a system crash the system. The vulnerability is rated with a CVSS score of 5.5 (Medium), indicating a moderate severity due to the requirement for local access and the potential for data integrity impact [3].

Mitigation

The fix has been included in the Linux kernel stable releases. Users should update their kernel to a version containing the commit that addresses this issue. The patch ensures proper locking during directory rename operations, preventing the race condition. No workaround is available other than applying the kernel update [1][2][3].