CVE-2026-52944 ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTLSETSPARSE FSCTLSETSPARSE in fsctlsetsparse modifies the file's sparse attribute and saves it through xattr without any permission checks. This exposes two...