s3-docs: Remove "experimental" label on VFS ACL modules
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1 <?xml version="1.0" encoding="iso-8859-1"?>
2 <!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
3 <chapter id="groupmapping">
4 <chapterinfo>
5         &author.jht;
6         <author>
7                 <firstname>Jean François</firstname><surname>Micouleau</surname>
8         </author>
9         &author.jerry;
10 </chapterinfo>
11 <title>Group Mapping: MS Windows and UNIX</title>
14         <para>
15 <indexterm significance="preferred"><primary>groups</primary><secondary>mapping</secondary></indexterm>
16 <indexterm><primary>SID</primary></indexterm>
17 <indexterm><primary>associations</primary></indexterm>
18 <indexterm><primary>UNIX groups</primary></indexterm>
19 <indexterm><primary>groupmap</primary></indexterm>
20 <indexterm><primary>net</primary></indexterm>
21         Starting with Samba-3, new group mapping functionality is available to create associations
22         between Windows group SIDs and UNIX group GIDs. The <command>groupmap</command> subcommand
23         included with the &net; tool can be used to manage these associations.
24         </para>
26         <para>
27 <indexterm><primary>group mapping</primary></indexterm>
28 <indexterm><primary>domain groups</primary></indexterm>
29         The new facility for mapping NT groups to UNIX system groups allows the administrator to decide
30         which NT domain groups are to be exposed to MS Windows clients. Only those NT groups that map
31         to a UNIX group that has a value other than the default (<constant>-1</constant>) will be exposed
32         in group selection lists in tools that access domain users and groups.
33         </para>
35         <warning>
36         <para>
37         <indexterm><primary>domain admin group</primary></indexterm>
38 <indexterm><primary>Windows group</primary></indexterm>
39         The <parameter>domain admin group</parameter> parameter has been removed in Samba-3 and should no longer
40         be specified in &smb.conf;. In Samba-2.2.x, this parameter was used to give the listed users membership in the
41         <constant>Domain Admins</constant> Windows group, which gave local admin rights on their workstations
42         (in default configurations).
43         </para>
44         </warning>
46 <sect1>
47 <title>Features and Benefits</title>
49         <para>
50         Samba allows the administrator to create MS Windows NT4/200x group accounts and to
51         arbitrarily associate them with UNIX/Linux group accounts.
52         </para>
54         <para>
55         <indexterm><primary>UID</primary></indexterm>
56         <indexterm><primary>GID</primary></indexterm>
57         <indexterm><primary>idmap uid</primary></indexterm>
58 <indexterm><primary>MMC</primary></indexterm>
59 <indexterm><primary>winbindd</primary></indexterm>
60 <indexterm><primary>ID range</primary></indexterm>
61 <indexterm><primary>group accounts</primary></indexterm>
62         Group accounts can be managed using the MS Windows NT4 or MS Windows 200x/XP Professional MMC tools.
63         Appropriate interface scripts should be provided in &smb.conf; if it is desired that UNIX/Linux system
64         accounts should be automatically created when these tools are used. In the absence of these scripts, and
65         so long as <command>winbindd</command> is running, Samba group accounts that are created using these
66         tools will be allocated UNIX UIDs and GIDs from the ID range specified by the
67         <smbconfoption name="idmap uid"/>/<smbconfoption name="idmap gid"/>
68         parameters in the &smb.conf; file.
69         </para>
71         <figure id="idmap-sid2gid">
72                 <title>IDMAP: Group SID-to-GID Resolution.</title>
73                 <imagefile scale="50">idmap-sid2gid</imagefile>
74         </figure>
76         <figure id="idmap-gid2sid">
77                 <title>IDMAP: GID Resolution to Matching SID.</title>
78         <imagefile scale="50">idmap-gid2sid</imagefile>
79         </figure>
81         <para>
82         <indexterm><primary>IDMAP</primary></indexterm>
83 <indexterm><primary>SID-to-GID</primary></indexterm>
84 <indexterm><primary>net</primary><secondary>groupmap</secondary></indexterm>
85 <indexterm><primary>group mappings</primary></indexterm>
86         In both cases, when winbindd is not running, only locally resolvable groups can be recognized. Please refer to
87         <link linkend="idmap-sid2gid">IDMAP: Group SID-to-GID Resolution</link> and <link
88         linkend="idmap-gid2sid">IDMAP: GID Resolution to Matching SID</link>.  The <command>net groupmap</command> is
89         used to establish UNIX group to NT SID mappings as shown in <link linkend="idmap-store-gid2sid">IDMAP: storing
90         group mappings</link>.
91         </para>
93         <figure id="idmap-store-gid2sid">
94                 <title>IDMAP Storing Group Mappings.</title>
95                 <imagefile scale="50">idmap-store-gid2sid</imagefile>
96         </figure>
98         <para>
99         <indexterm><primary>groupadd</primary></indexterm>
100         <indexterm><primary>groupdel</primary></indexterm>
101 <indexterm><primary>shadow utilities</primary></indexterm>
102 <indexterm><primary>groupmod</primary></indexterm>
103         Administrators should be aware that where &smb.conf; group interface scripts make
104         direct calls to the UNIX/Linux system tools (the shadow utilities, <command>groupadd</command>,
105         <command>groupdel</command>, and <command>groupmod</command>), the resulting UNIX/Linux group names will be subject
106         to any limits imposed by these tools. If the tool does not allow uppercase characters
107         or space characters, then the creation of an MS Windows NT4/200x-style group of
108         <literal>Engineering Managers</literal> will attempt to create an identically named
109         UNIX/Linux group, an attempt that will of course fail.
110         </para>
112         <para>
113         <indexterm><primary>GID</primary></indexterm>
114         <indexterm><primary>SID</primary></indexterm>
115         There are several possible workarounds for the operating system tools limitation. One
116         method is to use a script that generates a name for the UNIX/Linux system group that
117         fits the operating system limits and that then just passes the UNIX/Linux group ID (GID)
118         back to the calling Samba interface. This will provide a dynamic workaround solution.
119         </para>
121         <para>
122 <indexterm><primary>net</primary><secondary>groupmap</secondary></indexterm>
123         Another workaround is to manually create a UNIX/Linux group, then manually create the
124         MS Windows NT4/200x group on the Samba server, and then use the <command>net groupmap</command>
125         tool to connect the two to each other.
126         </para>
128 </sect1>
130 <sect1>
131 <title>Discussion</title>
133         <para>
134 <indexterm><primary>Windows NT4/200x</primary></indexterm>
135 <indexterm><primary>group privileges</primary></indexterm>
136         When you install <application>MS Windows NT4/200x</application> on a computer, the installation
137         program creates default users and groups, notably the <constant>Administrators</constant> group,
138         and gives that group privileges necessary to perform essential system tasks,
139         such as the ability to change the date and time or to kill (or close) any process running on the
140         local machine.
141         </para>
142         
143         <para>
144         <indexterm><primary>Administrator</primary></indexterm>
145         The <constant>Administrator</constant> user is a member of the <constant>Administrators</constant> group, and thus inherits
146         <constant>Administrators</constant> group privileges. If a <constant>joe</constant> user is created to be a member of the
147         <constant>Administrators</constant> group, <constant>joe</constant> has exactly the same rights as the user
148         <constant>Administrator</constant>.
149         </para>
151         <para>
152 <indexterm><primary>domain member</primary></indexterm>
153 <indexterm><primary>Domain Admins</primary></indexterm>
154 <indexterm><primary>inherits rights</primary></indexterm>
155 <indexterm><primary>PDC</primary></indexterm>
156         When an MS Windows NT4/200x/XP machine is made a domain member, the <quote>Domain Admins</quote> group of the
157         PDC is added to the local <constant>Administrators</constant> group of the workstation. Every member of the
158         <constant>Domain Admins</constant> group inherits the rights of the local <constant>Administrators</constant> group when
159         logging on the workstation.
160         </para>
162         <para>
163 <indexterm><primary>Domain Admins</primary></indexterm>
164 <indexterm><primary>PDC</primary></indexterm>
165         The following steps describe how to make Samba PDC users members of the <constant>Domain Admins</constant> group.
166         </para>
168         <orderedlist>
169                 <listitem><para>
170                 Create a UNIX group (usually in <filename>/etc/group</filename>); let's call it <constant>domadm</constant>.
171                 </para></listitem>
173                 <listitem><para>
174 <indexterm><primary>/etc/group</primary></indexterm>
175                 Add to this group the users that must be <quote>Administrators</quote>. For example,
176                 if you want <constant>joe, john</constant>, and <constant>mary</constant> to be administrators,
177                 your entry in <filename>/etc/group</filename> will look like this:
178                 </para>
180                 <para><programlisting>
181                 domadm:x:502:joe,john,mary
182                 </programlisting>
183                 </para></listitem>
185                 <listitem><para>
186                 Map this domadm group to the <quote>Domain Admins</quote> group by executing the command:
187                 </para>
189                 <para>
190 <screen>
191 &rootprompt;<userinput>net groupmap add ntgroup="Domain Admins" unixgroup=domadm rid=512 type=d</userinput>
192 </screen>
193                 </para>
194                 
195                 <para>
196                 <indexterm><primary>Domain Admins group</primary></indexterm>
197                 The quotes around <quote>Domain Admins</quote> are necessary due to the space in the group name.
198                 Also make sure to leave no white space surrounding the equal character (=).
199                 </para></listitem>
200         </orderedlist>
202         <para>
203         Now <constant>joe, john</constant>, and <constant>mary</constant> are domain administrators.
204         </para>
206         <para>
207         <indexterm><primary>groups</primary><secondary>domain</secondary></indexterm>
208         It is possible to map any arbitrary UNIX group to any Windows NT4/200x group as well as
209         to make any UNIX group a Windows domain group. For example, if you wanted to include a
210         UNIX group (e.g., acct) in an ACL on a local file or printer on a Domain Member machine,
211         you would flag that group as a domain group by running the following on the Samba PDC:
212         </para>
214         <para>
215 <screen>
216 &rootprompt;<userinput>net groupmap add rid=1000 ntgroup="Accounting" unixgroup=acct type=d</userinput>
217 </screen>
218         The <literal>ntgroup</literal> value must be in quotes if it contains space characters to prevent
219         the space from being interpreted as a command delimiter.
220         </para>
222         <para>
223 <indexterm><primary>RID</primary></indexterm>
224 <indexterm><primary>assigned RID</primary></indexterm>
225         Be aware that the RID parameter is an unsigned 32-bit integer that should
226         normally start at 1000. However, this RID must not overlap with any RID assigned
227         to a user. Verification for this is done differently depending on the passdb backend
228         you are using. Future versions of the tools may perform the verification automatically,
229         but for now the burden is on you.
230         </para>
232         <sect2>
233         <title>Warning: User Private Group Problems</title>
235         <para>
236 <indexterm><primary>group accounts</primary></indexterm>
237 <indexterm><primary>Red Hat Linux</primary></indexterm>
238 <indexterm><primary>private groups</primary></indexterm>
239         Windows does not permit user and group accounts to have the same name.
240         This has serious implications for all sites that use private group accounts.
241         A private group account is an administrative practice whereby users are each
242         given their own group account. Red Hat Linux, as well as several free distributions
243         of Linux, by default create private groups.
244         </para>
246         <para>
247 <indexterm><primary>UNIX/Linux group</primary></indexterm>
248 <indexterm><primary>Windows group</primary></indexterm>
249         When mapping a UNIX/Linux group to a Windows group account, all conflict can
250         be avoided by assuring that the Windows domain group name does not overlap
251         with any user account name.
252         </para>
254         </sect2>
256         <sect2>
257         <title>Nested Groups: Adding Windows Domain Groups to Windows Local Groups</title>
259         <indexterm><primary>groups</primary><secondary>nested</secondary></indexterm>
261         <para>
262 <indexterm><primary>nested groups</primary></indexterm>
263         This functionality is known as <constant>nested groups</constant> and was first added to
264         Samba-3.0.3.
265         </para>
267         <para>
268 <indexterm><primary>nested groups</primary></indexterm>
269         All MS Windows products since the release of Windows NT 3.10 support the use of nested groups.
270         Many Windows network administrators depend on this capability because it greatly simplifies security
271         administration.
272         </para>
274         <para>
275 <indexterm><primary>nested group</primary></indexterm>
276 <indexterm><primary>group membership</primary></indexterm>
277 <indexterm><primary>domain security</primary></indexterm>
278 <indexterm><primary>domain member server</primary></indexterm>
279 <indexterm><primary>local groups</primary></indexterm>
280 <indexterm><primary>domain global groups</primary></indexterm>
281 <indexterm><primary>domain global users</primary></indexterm>
282         The nested group architecture was designed with the premise that day-to-day user and group membership
283         management should be performed on the domain security database. The application of group security
284         should be implemented on domain member servers using only local groups. On the domain member server,
285         all file system security controls are then limited to use of the local groups, which will contain
286         domain global groups and domain global users.
287         </para>
289         <para>
290 <indexterm><primary>individual domain user</primary></indexterm>
291 <indexterm><primary>domain group settings</primary></indexterm>
292 <indexterm><primary>Account Unknown</primary></indexterm>
293         You may ask, What are the benefits of this arrangement? The answer is obvious to those who have plumbed
294         the dark depths of Windows networking architecture. Consider for a moment a server on which are stored
295         200,000 files, each with individual domain user and domain group settings. The company that owns the
296         file server is bought by another company, resulting in the server being moved to another location, and then
297         it is made a member of a different domain. Who would you think now owns all the files and directories?
298         Answer: Account Unknown.
299         </para>
301         <para>
302 <indexterm><primary>directory access control</primary></indexterm>
303 <indexterm><primary>local groups</primary></indexterm>
304 <indexterm><primary>ACL</primary></indexterm>
305 <indexterm><primary>Account Unknown</primary></indexterm>
306         Unraveling the file ownership mess is an unenviable administrative task that can be avoided simply
307         by using local groups to control all file and directory access control. In this case, only the members
308         of the local groups will have been lost. The files and directories in the storage subsystem will still
309         be owned by the local groups. The same goes for all ACLs on them. It is administratively much simpler
310         to delete the <constant>Account Unknown</constant> membership entries inside local groups with appropriate
311         entries for domain global groups in the new domain that the server has been made a member of.
312         </para>
314         <para>
315 <indexterm><primary>nested groups</primary></indexterm>
316 <indexterm><primary>administrative privileges</primary></indexterm>
317 <indexterm><primary>domain member workstations</primary></indexterm>
318 <indexterm><primary>domain member servers</primary></indexterm>
319 <indexterm><primary>member machine</primary></indexterm>
320 <indexterm><primary>full rights</primary></indexterm>
321 <indexterm><primary>Domain Admins</primary></indexterm>
322 <indexterm><primary>local administrative privileges</primary></indexterm>
323         Another prominent example of the use of nested groups involves implementation of administrative privileges
324         on domain member workstations and servers. Administrative privileges are given to all members of the
325         built-in local group <constant>Administrators</constant> on each domain member machine. To ensure that all domain
326         administrators have full rights on the member server or workstation, on joining the domain, the
327         <constant>Domain Admins</constant> group is added to the local Administrators group. Thus everyone who is
328         logged into the domain as a member of the Domain Admins group is also granted local administrative
329         privileges on each domain member.
330         </para>
332         <para>
333 <indexterm><primary>nested groups</primary></indexterm>
334 <indexterm><primary>auxiliary members</primary></indexterm>
335 <indexterm><primary>/etc/group</primary></indexterm>
336 <indexterm><primary>winbind</primary></indexterm>
337         UNIX/Linux has no concept of support for nested groups, and thus Samba has for a long time not supported
338         them either. The problem is that you would have to enter UNIX groups as auxiliary members of a group in
339         <filename>/etc/group</filename>. This does not work because it was not a design requirement at the time
340         the UNIX file system security model was implemented. Since Samba-2.2, the winbind daemon can provide
341         <filename>/etc/group</filename> entries on demand by obtaining user and group information from the domain
342         controller that the Samba server is a member of.
343         </para>
345         <para>
346 <indexterm><primary>/etc/group</primary></indexterm>
347 <indexterm><primary>libnss_winbind</primary></indexterm>
348 <indexterm><primary>local groups</primary></indexterm>
349 <indexterm><primary>Domain Users</primary></indexterm>
350 <indexterm><primary>alias group</primary></indexterm>
351         In effect, Samba supplements the <filename>/etc/group</filename> data via the dynamic
352         <command>libnss_winbind</command> mechanism. Beginning with Samba-3.0.3, this facility is used to provide
353         local groups in the same manner as Windows. It works by expanding the local groups on the
354         fly as they are accessed. For example, the <constant>Domain Users</constant> group of the domain is made
355         a member of the local group <constant>demo</constant>. Whenever Samba needs to resolve membership of the
356         <constant>demo</constant> local (alias) group, winbind asks the domain controller for demo members of the Domain Users
357         group. By definition, it can only contain user objects, which can then be faked to be member of the
358         UNIX/Linux group <constant>demo</constant>.
359         </para>
361         <para>
362 <indexterm><primary>nested groups</primary></indexterm>
363 <indexterm><primary>winbindd</primary></indexterm>
364 <indexterm><primary>NSS</primary></indexterm>
365 <indexterm><primary>winbind</primary></indexterm>
366 <indexterm><primary>local groups</primary></indexterm>
367 <indexterm><primary>Domain User Manager</primary></indexterm>
368 <indexterm><primary>net</primary><secondary>rpc</secondary><tertiary>group</tertiary></indexterm>
369         To enable the use of nested groups, <command>winbindd</command> must be used with NSS winbind.
370         Creation and administration of the local groups is done best via the Windows Domain User Manager or its
371         Samba equivalent, the utility <command>net rpc group</command>. Creating the local group
372         <constant>demo</constant> is achieved by executing:
373         <screen>
374         &rootprompt; net rpc group add demo -L -Uroot%not24get
375         </screen>
376 <indexterm><primary>addmem</primary></indexterm>
377 <indexterm><primary>delmem</primary></indexterm>
378         Here the -L switch means that you want to create a local group. It may be necessary to add -S and -U
379         switches for accessing the correct host with appropriate user or root privileges. Adding and removing
380         group members can be done via the <constant>addmem</constant> and <constant>delmem</constant> subcommands of
381         <command>net rpc group</command> command. For example, addition of <quote>DOM\Domain Users</quote> to the
382         local group <constant>demo</constant> is done by executing:
383         <screen>
384         net rpc group addmem demo "DOM\Domain Users"
385         </screen>
386 <indexterm><primary>getent group demo</primary></indexterm>
387 <indexterm><primary>trusted domain</primary></indexterm>
388 <indexterm><primary>foreign domain</primary></indexterm>
389 <indexterm><primary>local access permissions</primary></indexterm>
390         Having completed these two steps, the execution of <command>getent group demo</command> will show demo
391         members of the global <constant>Domain Users</constant> group as members of  the group
392         <constant>demo</constant>.  This also works with any local or domain user. In case the domain DOM trusts
393         another domain, it is also possible to add global users and groups of the trusted domain as members of
394         <constant>demo</constant>. The users from the foreign domain who are members of the group that has been
395         added to the <constant>demo</constant> group now have the same local access permissions as local domain
396         users have. 
397         </para>
399         </sect2>
401         <sect2>
402         <title>Important Administrative Information</title>
404         <para>
405         Administrative rights are necessary in two specific forms:
406         </para>
408         <orderedlist>
409                 <listitem><para>For Samba-3 domain controllers and domain member servers/clients.</para></listitem>
410                 <listitem><para>To manage domain member Windows workstations.</para></listitem>
411         </orderedlist>
413         <para>
414 <indexterm><primary>rights and privileges</primary></indexterm>
415 <indexterm><primary>domain member client</primary></indexterm>
416 <indexterm><primary>group account</primary></indexterm>
417         Versions of Samba up to and including 3.0.10 do not provide a means for assigning rights and privileges
418         that are necessary for system administration tasks from a Windows domain member client machine, so
419         domain administration tasks such as adding, deleting, and changing user and group account information, and
420         managing workstation domain membership accounts, can be handled by any account other than root.
421         </para>
423         <para>
424 <indexterm><primary>privilege management</primary></indexterm>
425 <indexterm><primary>delegated</primary></indexterm>
426 <indexterm><primary>Administrator</primary></indexterm>
427         Samba-3.0.11 introduced a new privilege management interface (see <link linkend="rights">User Rights and Privileges</link>)
428         that permits these tasks to be delegated to non-root (i.e., accounts other than the equivalent of the
429         MS Windows Administrator) accounts.
430         </para>
432         <para>
433 <indexterm><primary>mapped</primary></indexterm>
434 <indexterm><primary>Domain Admins</primary></indexterm>
435         Administrative tasks on a Windows domain member workstation can be done by anyone who is a member of the
436         <constant>Domain Admins</constant> group. This group can be mapped to any convenient UNIX group.
437         </para>
439         <sect3>
440         <title>Applicable Only to Versions Earlier than 3.0.11</title>
442         <para>
443 <indexterm><primary>privilege</primary></indexterm>
444         Administrative tasks on UNIX/Linux systems, such as adding users or groups, requires
445         <constant>root</constant>-level privilege. The addition of a Windows client to a Samba domain involves the
446         addition of a user account for the Windows client.
447         </para>
449         <para>
450 <indexterm><primary>system security</primary></indexterm>
451 <indexterm><primary>privileges</primary></indexterm>
452         Many UNIX administrators continue to request that the Samba Team make it possible to add Windows workstations, or 
453         the ability to add, delete, or modify user accounts, without requiring <constant>root</constant> privileges. 
454         Such a request violates every understanding of basic UNIX system security.
455         </para>
457         <para>
458 <indexterm><primary>privileges</primary></indexterm>
459 <indexterm><primary>/etc/passwd</primary></indexterm>
460 <indexterm><primary>Domain Server Manager</primary></indexterm>
461 <indexterm><primary>Domain User Manager</primary></indexterm>
462 <indexterm><primary>manage share-level ACL</primary></indexterm>
463 <indexterm><primary>share-level ACLs</primary></indexterm>
464         There is no safe way to provide access on a UNIX/Linux system without providing
465         <constant>root</constant>-level privileges. Provision of <constant>root</constant> privileges can be done
466         either by logging on to the Domain as the user <constant>root</constant> or by permitting particular users to
467         use a UNIX account that has a UID=0 in the <filename>/etc/passwd</filename> database. Users of such accounts
468         can use tools like the NT4 Domain User Manager and the NT4 Domain Server Manager to manage user and group
469         accounts as well as domain member server and client accounts. This level of privilege is also needed to manage
470         share-level ACLs.
471         </para>
473         </sect3>
475         </sect2>
477         <sect2>
478         <title>Default Users, Groups, and Relative Identifiers</title>
480         <para>
481         <indexterm><primary>Relative Identifier</primary><see>RID</see></indexterm>
482         <indexterm><primary>RID</primary></indexterm>
483 <indexterm><primary>Windows NT4/200x/XP</primary></indexterm>
484 <indexterm><primary>well-known RID</primary></indexterm>
485 <indexterm><primary>domain groups</primary></indexterm>
486 <indexterm><primary>tdbsam</primary></indexterm>
487 <indexterm><primary>LDAP</primary></indexterm>
488 <indexterm><primary>NT groups</primary></indexterm>
489         When first installed, Windows NT4/200x/XP are preconfigured with certain user, group, and
490         alias entities. Each has a well-known RID. These must be preserved for continued
491         integrity of operation. Samba must be provisioned with certain essential domain groups that require
492         the appropriate RID value. When Samba-3 is configured to use <constant>tdbsam</constant>, the essential
493         domain groups are automatically created. It is the LDAP administrator's responsibility to create
494         (provision) the default NT groups.
495         </para>
497         <para>
498 <indexterm><primary>default users</primary></indexterm>
499 <indexterm><primary>default groups</primary></indexterm>
500 <indexterm><primary>default aliases</primary></indexterm>
501 <indexterm><primary>RID</primary></indexterm>
502         Each essential domain group must be assigned its respective well-known RID. The default users, groups,
503         aliases, and RIDs are shown in <link linkend="WKURIDS">Well-Known User Default RIDs</link>.
504         </para>
506         <note><para>
507 <indexterm><primary>passdb backend</primary></indexterm>
508 <indexterm><primary>LDAP</primary></indexterm>
509 <indexterm><primary>ldapsam</primary></indexterm>
510 <indexterm><primary>domain groups</primary></indexterm>
511 <indexterm><primary>RID</primary></indexterm>
512         It is the administrator's responsibility to create the essential domain groups and to assign each
513         its default RID.
514         </para></note>
516         <para>
517 <indexterm><primary>domain groups</primary></indexterm>
518 <indexterm><primary>RID</primary></indexterm>
519         It is permissible to create any domain group that may be necessary; just make certain that the essential
520         domain groups (well known) have been created and assigned their default RIDs. Other groups you create may
521         be assigned any arbitrary RID you care to use.
522         </para>
524         <para>
525         Be sure to map each domain group to a UNIX system group. That is the only way to ensure that the group
526         will be available for use as an NT domain group.
527         </para>
529         <para>
530         <table frame="all" id="WKURIDS">
531         <title>Well-Known User Default RIDs</title>
532                 <tgroup cols="4" align="left">
533                         <colspec align="left"/>
534                         <colspec align="left"/>
535                         <colspec align="left"/>
536                         <colspec align="center"/>
537                         <thead>
538                                 <row>
539                                         <entry>Well-Known Entity</entry>
540                                         <entry>RID</entry>
541                                         <entry>Type</entry>
542                                         <entry>Essential</entry>
543                                 </row>
544                         </thead>
545                         <tbody>
546                                 <row>
547                                         <entry>Domain Administrator</entry>
548                                         <entry>500</entry>
549                                         <entry>User</entry>
550                                         <entry>No</entry>
551                                 </row>
552                                 <row>
553                                         <entry>Domain Guest</entry>
554                                         <entry>501</entry>
555                                         <entry>User</entry>
556                                         <entry>No</entry>
557                                 </row>
558                                 <row>
559                                         <entry>Domain KRBTGT</entry>
560                                         <entry>502</entry>
561                                         <entry>User</entry>
562                                         <entry>No</entry>
563                                 </row>
564                                 <row>
565                                         <entry>Domain Admins</entry>
566                                         <entry>512</entry>
567                                         <entry>Group</entry>
568                                         <entry>Yes</entry>
569                                 </row>
570                                 <row>
571                                         <entry>Domain Users</entry>
572                                         <entry>513</entry>
573                                         <entry>Group</entry>
574                                         <entry>Yes</entry>
575                                 </row>
576                                 <row>
577                                         <entry>Domain Guests</entry>
578                                         <entry>514</entry>
579                                         <entry>Group</entry>
580                                         <entry>Yes</entry>
581                                 </row>
582                                 <row>
583                                         <entry>Domain Computers</entry>
584                                         <entry>515</entry>
585                                         <entry>Group</entry>
586                                         <entry>No</entry>
587                                 </row>
588                                 <row>
589                                         <entry>Domain Controllers</entry>
590                                         <entry>516</entry>
591                                         <entry>Group</entry>
592                                         <entry>No</entry>
593                                 </row>
594                                 <row>
595                                         <entry>Domain Certificate Admins</entry>
596                                         <entry>517</entry>
597                                         <entry>Group</entry>
598                                         <entry>No</entry>
599                                 </row>
600                                 <row>
601                                         <entry>Domain Schema Admins</entry>
602                                         <entry>518</entry>
603                                         <entry>Group</entry>
604                                         <entry>No</entry>
605                                 </row>
606                                 <row>
607                                         <entry>Domain Enterprise Admins</entry>
608                                         <entry>519</entry>
609                                         <entry>Group</entry>
610                                         <entry>No</entry>
611                                 </row>
612                                 <row>
613                                         <entry>Domain Policy Admins</entry>
614                                         <entry>520</entry>
615                                         <entry>Group</entry>
616                                         <entry>No</entry>
617                                 </row>
618                                 <row>
619                                         <entry>Builtin Admins</entry>
620                                         <entry>544</entry>
621                                         <entry>Alias</entry>
622                                         <entry>No</entry>
623                                 </row>
624                                 <row>
625                                         <entry>Builtin users</entry>
626                                         <entry>545</entry>
627                                         <entry>Alias</entry>
628                                         <entry>No</entry>
629                                 </row>
630                                 <row>
631                                         <entry>Builtin Guests</entry>
632                                         <entry>546</entry>
633                                         <entry>Alias</entry>
634                                         <entry>No</entry>
635                                 </row>
636                                 <row>
637                                         <entry>Builtin Power Users</entry>
638                                         <entry>547</entry>
639                                         <entry>Alias</entry>
640                                         <entry>No</entry>
641                                 </row>
642                                 <row>
643                                         <entry>Builtin Account Operators</entry>
644                                         <entry>548</entry>
645                                         <entry>Alias</entry>
646                                         <entry>No</entry>
647                                 </row>
648                                 <row>
649                                         <entry>Builtin System Operators</entry>
650                                         <entry>549</entry>
651                                         <entry>Alias</entry>
652                                         <entry>No</entry>
653                                 </row>
654                                 <row>
655                                         <entry>Builtin Print Operators</entry>
656                                         <entry>550</entry>
657                                         <entry>Alias</entry>
658                                         <entry>No</entry>
659                                 </row>
660                                 <row>
661                                         <entry>Builtin Backup Operators</entry>
662                                         <entry>551</entry>
663                                         <entry>Alias</entry>
664                                         <entry>No</entry>
665                                 </row>
666                                 <row>
667                                         <entry>Builtin Replicator</entry>
668                                         <entry>552</entry>
669                                         <entry>Alias</entry>
670                                         <entry>No</entry>
671                                 </row>
672                                 <row>
673                                         <entry>Builtin RAS Servers</entry>
674                                         <entry>553</entry>
675                                         <entry>Alias</entry>
676                                         <entry>No</entry>
677                                 </row>
678                         </tbody>
679                 </tgroup>
680         </table>
681         </para>
683         </sect2>
685         <sect2>
686         <title>Example Configuration</title>
688                 <para>
689 <indexterm><primary>net</primary><secondary>groupmap</secondary><tertiary>list</tertiary></indexterm>
690                 You can list the various groups in the mapping database by executing
691                 <command>net groupmap list</command>. Here is an example:
692                 </para>
694                 <para>
695 <indexterm><primary>net</primary><secondary>groupmap</secondary></indexterm>
696 <screen>
697 &rootprompt; <userinput>net groupmap list</userinput>
698 Domain Admins (S-1-5-21-2547222302-1596225915-2414751004-512) -> domadmin
699 Domain Users (S-1-5-21-2547222302-1596225915-2414751004-513) -> domuser
700 Domain Guests (S-1-5-21-2547222302-1596225915-2414751004-514) -> domguest
701 </screen>
702                 </para>
704                 <para>
705                 For complete details on <command>net groupmap</command>, refer to the net(8) man page.
706                 </para>
708         </sect2>
710 </sect1>
712 <sect1>
713 <title>Configuration Scripts</title>
715         <para>
716         Everyone needs tools. Some of us like to create our own, others prefer to use canned tools
717         (i.e., prepared by someone else for general use). 
718         </para>
720         <sect2>
721         <title>Sample &smb.conf; Add Group Script</title>
723                 <para>
724                 <indexterm><primary>smbgrpadd.sh</primary></indexterm>
725                 <indexterm><primary>groupadd limitations</primary></indexterm>
726                 <indexterm><primary>smbgrpadd.sh</primary></indexterm>
727 <indexterm><primary>/etc/group</primary></indexterm>
728 <indexterm><primary>groupadd</primary></indexterm>
729                 A script to create complying group names for use by the Samba group interfaces
730                 is provided in <link linkend="smbgrpadd.sh">smbgrpadd.sh</link>. This script
731                 adds a temporary entry in the <filename>/etc/group</filename> file and then renames
732                 it to the desired name. This is an example of a method to get around operating
733                 system maintenance tool limitations such as those present in some version of the
734                 <command>groupadd</command> tool.
735 <example id="smbgrpadd.sh">
736 <title>smbgrpadd.sh</title>
737 <programlisting>
738 #!/bin/bash
740 # Add the group using normal system groupadd tool.
741 groupadd smbtmpgrp00
743 thegid=`cat /etc/group | grep ^smbtmpgrp00 | cut -d ":" -f3`
745 # Now change the name to what we want for the MS Windows networking end
746 cp /etc/group /etc/group.bak
747 cat /etc/group.bak | sed "s/^smbtmpgrp00/$1/g" > /etc/group
748 rm /etc/group.bak
750 # Now return the GID as would normally happen.
751 echo $thegid
752 exit 0
753 </programlisting>
754 </example>
755 </para>
757                 <para>
758                 The &smb.conf; entry for the above script shown in <link linkend="smbgrpadd">the configuration of
759                 &smb.conf; for the add group Script</link> demonstrates how it may be used.
761 <example id="smbgrpadd">
762 <title>Configuration of &smb.conf; for the add group Script</title>
763 <smbconfblock>
764 <smbconfsection name="[global]"/>
765 <smbconfoption name="add group script">/path_to_tool/smbgrpadd.sh &quot;%g&quot;</smbconfoption>
766 </smbconfblock>
767 </example>
768                 </para>
770         </sect2>
771         
772         <sect2>
773         <title>Script to Configure Group Mapping</title>
775         <para>
776 <indexterm><primary>initGroups.sh</primary></indexterm>
777         In our example we have created a UNIX/Linux group called <literal>ntadmin</literal>.
778         Our script will create the additional groups <literal>Orks</literal>, <literal>Elves</literal>, and <literal>Gnomes</literal>.
779         It is a good idea to save this shell script for later use just in case you ever need to rebuild your mapping database.
780         For the sake of convenience we elect to save this script as a file called <filename>initGroups.sh</filename>.
781         This script is given in <link linkend="set-group-map">intGroups.sh</link>.
782 <indexterm><primary>initGroups.sh</primary></indexterm>
783 <example id="set-group-map">
784 <title>Script to Set Group Mapping</title>
785 <programlisting>
786 #!/bin/bash
788 net groupmap add ntgroup="Domain Admins" unixgroup=ntadmin rid=512 type=d
789 net groupmap add ntgroup="Domain Users" unixgroup=users rid=513 type=d
790 net groupmap add ntgroup="Domain Guests" unixgroup=nobody rid=514 type=d
792 groupadd Orks
793 groupadd Elves
794 groupadd Gnomes
796 net groupmap add ntgroup="Orks"   unixgroup=Orks   type=d
797 net groupmap add ntgroup="Elves"  unixgroup=Elves  type=d
798 net groupmap add ntgroup="Gnomes" unixgroup=Gnomes type=d
799 </programlisting>
800 </example>
801         </para>
803         <para>
804         Of course it is expected that the administrator will modify this to suit local needs.
805         For information regarding the use of the <command>net groupmap</command> tool please
806         refer to the man page.
807         </para>
809         <note><para>
810         Versions of Samba-3 prior to 3.0.23 automatically create default group mapping for the
811         <literal>Domain Admins, Domain Users</literal> and <literal>Domain Guests</literal> Windows
812         groups, but do not map them to UNIX GIDs. This was a cause of administrative confusion and 
813         trouble. Commencing with Samba-3.0.23 this anomaly has been fixed - thus all Windows groups
814         must now be manually and explicitly created and mapped to a valid UNIX GID by the Samba 
815         administrator.
816         </para></note>
818         </sect2>
820 </sect1>
822 <sect1>
823 <title>Common Errors</title>
825 <para>
826 At this time there are many little surprises for the unwary administrator. In a real sense
827 it is imperative that every step of automated control scripts be carefully tested
828 manually before putting it into active service.
829 </para>
831         <sect2>
832         <title>Adding Groups Fails</title>
834                 <para>
835 <indexterm><primary>groupadd</primary></indexterm>
836                 This is a common problem when the <command>groupadd</command> is called directly
837                 by the Samba interface script for the <smbconfoption name="add group script"/> in
838                 the &smb.conf; file.
839                 </para>
841                 <para>
842 <indexterm><primary>uppercase character</primary></indexterm>
843 <indexterm><primary>space character</primary></indexterm>
844                 The most common cause of failure is an attempt to add an MS Windows group account
845                 that has an uppercase character and/or a space character in it.
846                 </para>
848                 <para>
849 <indexterm><primary>groupadd</primary></indexterm>
850                 There are three possible workarounds. First, use only group names that comply
851                 with the limitations of the UNIX/Linux <command>groupadd</command> system tool.
852                 Second, it involves the use of the script mentioned earlier in this chapter, and
853                 third is the option is to manually create a UNIX/Linux group account that can substitute
854                 for the MS Windows group name, then use the procedure listed above to map that group
855                 to the MS Windows group.
856                 </para>
858         </sect2>
860         <sect2>
861         <title>Adding Domain Users to the Workstation Power Users Group</title>
863                 <para><quote>
864                 What must I do to add domain users to the Power Users group?
865                 </quote></para>
867                 <para>
868 <indexterm><primary>Domain Users group</primary></indexterm>
869                 The Power Users group is a group that is local to each Windows 200x/XP Professional workstation.
870                 You cannot add the Domain Users group to the Power Users group automatically, it must be done on
871                 each workstation by logging in as the local workstation <emphasis>administrator</emphasis> and
872                 then using the following procedure:
873                 </para>
875                 <procedure>
876                         <step><para>
877                         Click <guimenu>Start -> Control Panel -> Users and Passwords</guimenu>.
878                         </para></step>
880                         <step><para>
881                         Click the <guimenuitem>Advanced</guimenuitem> tab.
882                         </para></step>
884                         <step><para>
885                         Click the <guibutton>Advanced</guibutton> button.
886                         </para></step>
888                         <step><para>
889                         Click <constant>Groups</constant>.
890                         </para></step>
892                         <step><para>
893                         Double-click <constant>Power Users</constant>. This will launch the panel to add users or groups
894                         to the local machine <constant>Power Users</constant> group.
895                         </para></step>
897                         <step><para>
898                         Click the <guibutton>Add</guibutton> button.
899                         </para></step>
901                         <step><para>
902                         Select the domain from which the <constant>Domain Users</constant> group is to be added.
903                         </para></step>
905                         <step><para>
906                         Double-click the <constant>Domain Users</constant> group.
907                         </para></step>
909                         <step><para>
910                         Click the <guibutton>OK</guibutton> button. If a logon box is presented during this process, 
911                         please remember to enter the connect as <constant>DOMAIN\UserName</constant>, that is, for the
912                         domain <constant>MIDEARTH</constant> and the user <constant>root</constant> enter
913                         <constant>MIDEARTH\root</constant>.
914                         </para></step>
915                 </procedure>
916         </sect2>
918 </sect1>
920 </chapter>