Linux Kernel CIFS Uninitialized Variable Vulnerability in SMB3 Transformation

A vulnerability in the Linux kernel's CIFS (Common Internet File System) implementation has been addressed. The issue arose from an uninitialized variable in the SMB3 request transformation function. This vulnerability could lead to a kernel oops, which is a type of error that can cause a system crash. The problem was caused by the 'smb3_init_transform_rq()' function not properly initializing a buffer variable before passing it to 'netfs_alloc_folioq_buffer()'. As a result, the buffer contained an undefined value, which could cause netfs to append data incorrectly. The vulnerability affects the Linux kernel stable tree.

Impact

The vulnerability could lead to a kernel oops, causing a system crash.

Reproduction

The vulnerability can be reproduced by invoking the 'smb3_init_transform_rq()' function in the CIFS implementation without the buffer variable being properly initialized. This can be done by creating a scenario where the function is called with an uninitialized buffer, allowing netfs to append data to it incorrectly, which can then lead to a kernel oops.

Remediation

Users can upgrade to the latest version of the Linux kernel stable tree, where this vulnerability has been fixed.