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Samba HowTo Guide
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Viewing File or Directory Permissions

The third button is the Permissions button. Clicking on it brings up a dialog box that shows both the permissions and the UNIX owner of the file or directory. The owner is displayed like this:

SERVER \ user (Long name)

SERVER is the NetBIOS name of the Samba server, user is the username of the UNIX user who owns the file, and (Long name) is the descriptive string identifying the user (normally found in the GECOS field of the UNIX password database).

If the parameter nt acl support is set to false, the file owner will be shown as the NT user Everyone, and the permissions will be shown as NT Full Control .

The permissions field is displayed differently for files and directories. Both are discussed next.

File Permissions

The standard UNIX user/group/world triplet and the corresponding read, write, execute permissions triplets are mapped by Samba into a three-element NT ACL with the “r”, “w”, and “x” bits mapped into the corresponding NT permissions. The UNIX world permissions are mapped into the global NT group Everyone, followed by the list of permissions allowed for the UNIX world. The UNIX owner and group permissions are displayed as an NT user icon and an NT local group icon, respectively, followed by the list of permissions allowed for the UNIX user and group.

Because many UNIX permission sets do not map into common NT names such as read, change, or full control, usually the permissions will be prefixed by the words Special Access in the NT display list.

But what happens if the file has no permissions allowed for a particular UNIX user group or world component? In order to allow no permissions to be seen and modified, Samba then overloads the NT Take Ownership ACL attribute (which has no meaning in UNIX) and reports a component with no permissions as having the NT O bit set. This was chosen, of course, to make it look like a zero, meaning zero permissions. More details on the decision behind this action are given below.

Directory Permissions

Directories on an NT NTFS file system have two different sets of permissions. The first set is the ACL set on the directory itself, which is usually displayed in the first set of parentheses in the normal RW NT style. This first set of permissions is created by Samba in exactly the same way as normal file permissions are, described above, and is displayed in the same way.

The second set of directory permissions has no real meaning in the UNIX permissions world and represents the inherited permissions that any file created within this directory would inherit.

Samba synthesizes these inherited permissions for NT by returning as an NT ACL the UNIX permission mode that a new file created by Samba on this share would receive.

Samba HowTo Guide
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  Published under the terms fo the GNU General Public License Design by Interspire