CVE-2026-97561smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid When the administrator mounts with forceuid or forcegid (uid=/gid= mount options), they expect all files to appear owned by the specified user/group. However, several code paths unconditionally called sid_to_id() to overwrite cf_uid/cf_gid with server-provided values, ignoring the administrator's explicit override: - smb311_posix_info_to_fattr() (stat via POSIX extensions) - cifs_posix_to_fattr() (readdir via POSIX extensions) - parse_sec_desc() (CIFS ACL ownership mapping) This allowed an untrusted server to dictate local file ownership even when the mount was configured to force specific uid/gid values. Fix all three call sites to check CIFS_MOUNT_OVERR_UID and CIFS_MOUNT_OVERR_GID before calling sid_to_id(), following the same pattern already used by cifs_unix_basic_to_fattr() for unix extensions.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/89a3b4704af2208e381c55037ff2d1e2365b83e4
• https://git.kernel.org/stable/c/be6eccccec867c22d7c65fab4ea4e91ec3d5b8c6
• https://git.kernel.org/stable/c/bc35de451c128d399ad185d6269f8847e97cd1c9
• https://git.kernel.org/stable/c/6ac7a29691558bed18e2df1780636b8aa0fd13d5
• https://git.kernel.org/stable/c/e1b74f8f8c1d13190b09fe623b729d36b7ac22a8
• https://git.kernel.org/stable/c/18a72975e9f35aadecc75b031f693f2d1f49308f