HP CIFS Server 3.0f Administrator's Guide verison A.02.03

UNIX Owning Group Translation in NT ACL
The owning group on a UNIX file system is represented on the Windows NT client with the take ownership
(O) permission. While the meaning of the take ownership permission on NT doesn't exactly match the
meaning of an owning group on the UNIX file system, this permission is still translated into the take ownership
permission.
This representation becomes even more significant when translating VxFS POSIX ACLs, as there can be many
groups with different permissions on an individual file in this file system. Without this permission type, you
would not be able to tell the owning group entry from other group entries.
For example, if an owning group named sales on the UNIX file system has. read and execute (r-x) permissions
on a file, the Windows NT client will display the permissions for group sales as:
Special Access (RXO)
UNIX Other Permission Translation in NT ACL
In UNIX, the other permission entry represents permissions for any user or group that is not the owner , and
doesn't belong to the owning group . This entry maps to the everyone access control entry on the Windows
NT client.
NT Directory and File Permission Translations
Windows NT clients display two sets of permissions for directory entries: directory permissions and file
permissions. Directory Permissions are the permissions for the directory itself. File Permissions are the
permissions inherited by the files and subdirectories created in the directory. Samba translates UNIX
permissions for a directory into Windows NT directory permissions and vice versa. Windows NT file
permissions are not supported when the translation is to/from UNIX permissions.
NT file permissions , however, are supported with VxFS POSIX ACLs (as described in the next section).
Setting UNIX Permissions from Windows NT
With one exception, reversing the UNIX to NT translations described above will always work. You cannot,
however, change the owner or owning group by adding Special Access(DPO) or Special Access(O ) to a
user or group from the client.
All NT permissions, except read, write and execute, are disregarded when applied to files on the Samba
server. These include delete (D), change permissions (P) and take ownership (O).
The table below shows how NT access types map to UNIX permissions:
Table 3-2 NT Access Type Maps to UNIX Permission
UNIX PermissionNT access type
r--Special Access(R)
-w-Special Access(W)
--xSpecial Access(X)
rw-Special Access(RW)
r-xRead(RX)
-wxSpecial Access(WX)
rwxSpecial Access(RWX)
r--Special Access
When mapping to UNIX file permissions from NT, you will not be able to add new NT ACL entries because
only the owner , owning group and other ACL entries are supported by UNIX permissions. UNIX ignores
unrecognized entries. Conversely, you cannot delete any of the three entries listed above as these entries
are required by UNIX.
Pre-defined NT Permissions
The Windows NT Explorer ACL interface allows you to choose predefined permissions like Change and Full
Control in addition to creating custom Special Access permissions.
42 Managing HP-UX File Access Permissions from Windows NT/XP/2000