CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's ksmbd component, allowing write-capable users to bypass directory restrictions and create zero-length files or directories outside the intended share due to a flaw in the caseless retry logic. This can lead to unauthorized access and manipulation of file system structures, posing a significant risk to system integrity. Organizations using Linux systems with ksmbd should prioritize patching this vulnerability to mitigate potential exploitation.
Original NVD Description
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.