Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent path traversal bypass by restricting caseless retry ksmbd_vfs_path_lookup() enforces LOOKUP_BENEATH to restrict path resolution within the share root. When a crafted path attempts to escape the share boundary using parent-directory components ('..'), vfs_path_parent_lookup() detects this and immediately fails, returning -EXDEV. However, a bug exists in __ksmbd_vfs_kern_path() under caseless mode. The function fails to intercept the -EXDEV error and erroneously falls through to the caseless retry logic, which is intended only for genuinely missing files. During this retry process, the path is reconstructed, leading to an unintended LOOKUP_BENEATH bypass that allows write-capable users to create zero-length files or directories outside the exported share. Fix this by ensuring that the execution only proceeds to the caseless lookup retry when the error is specifically -ENOENT. Any other errors, such as -EXDEV from a path traversal attempt, must be returned immediately.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 74d7970febf7e9005375aeda0df821d2edffc9f7 before eec1dd2586c4016b7555a5d047db2b3756459fb2; affected 74d7970febf7e9005375aeda0df821d2edffc9f7 before a1c331d98313380c38f616c8b28b890ec8ef9c28; affected 74d7970febf7e9005375aeda0df821d2edffc9f7 before cfb5a56c218888f9d74165dff0c282cd0be97983; affected 74d7970febf7e9005375aeda0df821d2edffc9f7 before 8c9a4f1327eb71efbf14842e7b8a6d965077eb67; affected 74d7970febf7e9005375aeda0df821d2edffc9f7 before 54bab9ba5a9f156ffa9324fcbe5a356fd0242f95; affected 019aae488dbc67c97a33db03652e20e2c9e3afa7; affected 6927ffe7479c72e7ebf885507227266a75f7c97d; affected ef6cc1c465786b3e4e735d1ab8b616b3e94402df; affected 5.15.145 before 5.16; affected 6.1.71 before 6.2; affected 6.3.10 before 6.4 |
| Linux / Linux | affected 6.4; unaffected 0 before 6.4; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.1.4 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/eec1dd2586c4016b7555a5d047db2b3756459fb2
- https://git.kernel.org/stable/c/a1c331d98313380c38f616c8b28b890ec8ef9c28
- https://git.kernel.org/stable/c/cfb5a56c218888f9d74165dff0c282cd0be97983
- https://git.kernel.org/stable/c/8c9a4f1327eb71efbf14842e7b8a6d965077eb67
- https://git.kernel.org/stable/c/54bab9ba5a9f156ffa9324fcbe5a356fd0242f95