vfs_acl_xattr — Save NTFS-ACLs in Extended Attributes (EAs)
vfs objects = acl_xattr
This VFS module is part of the samba(7) suite.
This module is made for systems which do not support standardized NFS4 ACLs but only a deprecated POSIX ACL draft implementation. This is usually the case on Linux systems. Systems that do support NFS4 ACLs should just use those instead of this module.
vfs_acl_xattr VFS module stores
NTFS Access Control Lists (ACLs) in Extended Attributes (EAs).
This enables the full mapping of Windows ACLs on Samba
servers even if the ACL implementation is not capable to do so.
The NT ACLs are stored SID-based in the Extended Attribute
security.NTACL of a file or directory.
This Attribute is not listed by the Linux
getfattr -d .
To show the current value, the name of the EA must be specified
getfattr -n security.NTACL ).
This module forces the following parameters:
inherit acls = true
dos filemode = true
force unknown acl user = true
This module is stackable.
This option allows to redefine the default location for the NTACL extended attribute (xattr). If not set, NTACL xattrs are written to security.NTACL which is a protected location, which means the content of the security.NTACL attribute is not accessible from normal users outside of Samba. When this option is set to use a user-defined value, e.g. user.NTACL then any user can potentially access and overwrite this information. The module prevents access to this xattr over SMB, but the xattr may still be accessed by other means (eg local access, SSH, NFS). This option must only be used when this consequence is clearly understood and when specific precautions are taken to avoid compromising the ACL content.
When set to yes, a best effort mapping from/to the POSIX draft ACL layer will not be done by this module. The default is no, which means that Samba keeps setting and evaluating both the system ACLs and the NT ACLs. This is better if you need your system ACLs be set for local or NFS file access, too. If you only access the data via Samba you might set this to yes to achieve better NT ACL compatibility.
If acl_xattr:ignore system acls is set to yes, the following additional settings will be enforced:
create mask = 0666
directory mask = 0777
map archive = no
map hidden = no
map readonly = no
map system = no
store dos attributes = yes
This parameter determines the type of ACL that is synthesized in case a file or directory lacks an security.NTACL xattr.
When set to posix, an ACL will be synthesized based on the POSIX mode permissions for user, group and others, with an additional ACE for NT Authority\SYSTEM will full rights.
When set to windows, an ACL is synthesized the same way Windows does it, only including permissions for the owner and NT Authority\SYSTEM.
When set to everyone, an ACL is synthesized giving full permissions to everyone (S-1-1-0).
The default for this option is posix.