1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 12. Mapping MS Windows and Unix Groups</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="SAMBA Project Documentation"><link rel="up" href="optional.html" title="Part III. Advanced Configuration"><link rel="previous" href="passdb.html" title="Chapter 11. Account Information Databases"><link rel="next" href="AccessControls.html" title="Chapter 13. File, Directory and Share Access Controls"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 12. Mapping MS Windows and Unix Groups</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="passdb.html">Prev</a> </td><th width="60%" align="center">Part III. Advanced Configuration</th><td width="20%" align="right"> <a accesskey="n" href="AccessControls.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="groupmapping"></a>Chapter 12. Mapping MS Windows and Unix Groups</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Jean François</span> <span class="surname">Micouleau</span></h3></div></div><div><div class="author"><h3 class="author"><span class="firstname">Gerald</span> <span class="othername">(Jerry)</span> <span class="surname">Carter</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:jerry@samba.org">jerry@samba.org</a>></tt></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:jht@samba.org">jht@samba.org</a>></tt></p></div></div></div></div></div><div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="groupmapping.html#id2921449">Features and Benefits</a></dt><dt><a href="groupmapping.html#id2921551">Discussion</a></dt><dd><dl><dt><a href="groupmapping.html#id2921742">Example Configuration</a></dt></dl></dd><dt><a href="groupmapping.html#id2921806">Configuration Scripts</a></dt><dd><dl><dt><a href="groupmapping.html#id2921820">Sample smb.conf add group script</a></dt><dt><a href="groupmapping.html#id2921889">Script to configure Group Mapping</a></dt></dl></dd><dt><a href="groupmapping.html#id2921981">Common Errors</a></dt><dd><dl><dt><a href="groupmapping.html#id2921997">Adding Groups Fails</a></dt><dt><a href="groupmapping.html#id2922057">Adding MS Windows Groups to MS Windows Groups Fails</a></dt></dl></dd></dl></div><p>
2 Starting with Samba-3, new group mapping functionality is available to create associations
3 between Windows group SIDs and UNIX groups. The <i class="parameter"><tt>groupmap</tt></i> subcommand
4 included with the <span class="application">net</span> tool can be used to manage these associations.
5 </p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>
6 The first immediate reason to use the group mapping on a Samba PDC, is that
7 the <i class="parameter"><tt>domain admin group</tt></i> has been removed and should no longer
8 be specified in <tt class="filename">smb.conf</tt>. This parameter was used to give the listed users membership
9 in the <tt class="constant">Domain Admins</tt> Windows group which gave local admin rights on their workstations
10 (in default configurations).
11 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2921449"></a>Features and Benefits</h2></div></div><div></div></div><p>
12 Samba allows the administrator to create MS Windows NT4 / 200x group accounts and to
13 arbitrarily associate them with Unix/Linux group accounts.
15 Group accounts can be managed using the MS Windows NT4 or MS Windows 200x MMC tools
16 so long as appropriate interface scripts have been provided to <tt class="filename">smb.conf</tt>.
18 Administrators should be aware that where <tt class="filename">smb.conf</tt> group interface scripts make
19 direct calls to the Unix/Linux system tools (eg: the shadow utilities, <b class="command">groupadd</b>,
20 <b class="command">groupdel</b>, <b class="command">groupmod</b>) then the resulting Unix/Linux group names will be subject
21 to any limits imposed by these tools. If the tool does NOT allow upper case characters
22 or space characters, then the creation of an MS Windows NT4 / 200x style group of
23 <i class="parameter"><tt>Engineering Managers</tt></i> will attempt to create an identically named
24 Unix/Linux group, an attempt that will of course fail!
26 There are several possible work-arounds for the operating system tools limitation. One
27 method is to use a script that generates a name for the Unix/Linux system group that
28 fits the operating system limits, and that then just passes the Unix/Linux group id (GID)
29 back to the calling Samba interface. This will provide a dynamic work-around solution.
31 Another work-around is to manually create a Unix/Linux group, then manually create the
32 MS Windows NT4 / 200x group on the Samba server and then use the <b class="command">net groupmap</b>
33 tool to connect the two to each other.
34 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2921551"></a>Discussion</h2></div></div><div></div></div><p>
35 When installing <span class="application">MS Windows NT4 / 200x</span> on a computer, the installation
36 program creates default users and groups, notably the <tt class="constant">Administrators</tt> group,
37 and gives that group privileges necessary privileges to perform essential system tasks.
38 eg: Ability to change the date and time or to kill (or close) any process running on the
41 The 'Administrator' user is a member of the 'Administrators' group, and thus inherits
42 'Administrators' group privileges. If a 'joe' user is created to be a member of the
43 'Administrator' group, 'joe' has exactly the same rights as 'Administrator'.
45 When an MS Windows NT4 / W200x is made a domain member, the "Domain Admins" group of the
46 PDC is added to the local 'Administrators' group of the workstation. Every member of the
47 'Domain Administrators' group inherits the rights of the local 'Administrators' group when
48 logging on the workstation.
50 The following steps describe how to make Samba PDC users members of the 'Domain Admins' group?
51 </p><div class="orderedlist"><ol type="1"><li><p>
52 create a unix group (usually in <tt class="filename">/etc/group</tt>), let's call it domadm
53 </p></li><li><p>add to this group the users that must be Administrators. For example
54 if you want joe, john and mary, your entry in <tt class="filename">/etc/group</tt> will
56 </p><pre class="programlisting">
57 domadm:x:502:joe,john,mary
60 Map this domadm group to the "Domain Admins" group by running the command:
62 </p><pre class="screen">
63 <tt class="prompt">root# </tt><b class="userinput"><tt>net groupmap add ntgroup="Domain Admins" unixgroup=domadm</tt></b>
66 The quotes around "Domain Admins" are necessary due to the space in the group name.
67 Also make sure to leave no whitespace surrounding the equal character (=).
68 </p></li></ol></div><p>
69 Now joe, john and mary are domain administrators!
71 It is possible to map any arbitrary UNIX group to any Windows NT4 / 200x group as well as
72 making any UNIX group a Windows domain group. For example, if you wanted to include a
73 UNIX group (e.g. acct) in a ACL on a local file or printer on a domain member machine,
74 you would flag that group as a domain group by running the following on the Samba PDC:
76 </p><pre class="screen">
77 <tt class="prompt">root# </tt><b class="userinput"><tt>net groupmap add rid=1000 ntgroup="Accounting" unixgroup=acct</tt></b>
80 Be aware that the RID parameter is a unsigned 32 bit integer that should
81 normally start at 1000. However, this rid must not overlap with any RID assigned
82 to a user. Verifying this is done differently depending on on the passdb backend
83 you are using. Future versions of the tools may perform the verification automatically,
84 but for now the burden is on you.
85 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2921742"></a>Example Configuration</h3></div></div><div></div></div><p>
86 You can list the various groups in the mapping database by executing
87 <b class="command">net groupmap list</b>. Here is an example:
89 </p><pre class="screen">
90 <tt class="prompt">root# </tt> <b class="userinput"><tt>net groupmap list</tt></b>
91 System Administrators (S-1-5-21-2547222302-1596225915-2414751004-1002) -> sysadmin
92 Domain Admins (S-1-5-21-2547222302-1596225915-2414751004-512) -> domadmin
93 Domain Users (S-1-5-21-2547222302-1596225915-2414751004-513) -> domuser
94 Domain Guests (S-1-5-21-2547222302-1596225915-2414751004-514) -> domguest
97 For complete details on <b class="command">net groupmap</b>, refer to the net(8) man page.
98 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2921806"></a>Configuration Scripts</h2></div></div><div></div></div><p>
99 Everyone needs tools. Some of us like to create our own, others prefer to use canned tools
100 (ie: prepared by someone else for general use).
101 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2921820"></a>Sample <tt class="filename">smb.conf</tt> add group script</h3></div></div><div></div></div><p>
102 A script to great complying group names for use by the Samba group interfaces:
104 </p><div class="example"><a name="id2921843"></a><p class="title"><b>Example 12.1. smbgrpadd.sh</b></p><pre class="programlisting">
108 # Add the group using normal system groupadd tool.
111 thegid=`cat /etc/group | grep smbtmpgrp00 | cut -d ":" -f3`
113 # Now change the name to what we want for the MS Windows networking end
114 cp /etc/group /etc/group.bak
115 cat /etc/group.bak | sed s/smbtmpgrp00/$1/g > /etc/group
117 # Now return the GID as would normally happen.
122 The <tt class="filename">smb.conf</tt> entry for the above script would look like:
123 </p><pre class="programlisting">
124 add group script = /path_to_tool/smbgrpadd.sh %g
126 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2921889"></a>Script to configure Group Mapping</h3></div></div><div></div></div><p>
127 In our example we have created a Unix/Linux group called <i class="parameter"><tt>ntadmin</tt></i>.
128 Our script will create the additional groups <i class="parameter"><tt>Engineers, Marketoids, Gnomes</tt></i>:
130 </p><pre class="programlisting">
133 net groupmap modify ntgroup="Domain Admins" unixgroup=ntadmin
134 net groupmap modify ntgroup="Domain Users" unixgroup=users
135 net groupmap modify ntgroup="Domain Guests" unixgroup=nobody
136 net groupmap modify ntgroup="Administrators" unixgroup=root
137 net groupmap modify ntgroup="Users" unixgroup=users
138 net groupmap modify ntgroup="Guests" unixgroup=nobody
139 net groupmap modify ntgroup="System Operators" unixgroup=sys
140 net groupmap modify ntgroup="Account Operators" unixgroup=root
141 net groupmap modify ntgroup="Backup Operators" unixgroup=bin
142 net groupmap modify ntgroup="Print Operators" unixgroup=lp
143 net groupmap modify ntgroup="Replicators" unixgroup=daemon
144 net groupmap modify ntgroup="Power Users" unixgroup=sys
150 #net groupmap add ntgroup="Engineers" unixgroup=Engineers type=d
151 #net groupmap add ntgroup="Marketoids" unixgroup=Marketoids type=d
152 #net groupmap add ntgroup="Gnomes" unixgroup=Gnomes type=d
155 Of course it is expected that the administrator will modify this to suit local needs.
156 For information regarding the use of the <b class="command">net groupmap</b> tool please
157 refer to the man page.
158 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2921981"></a>Common Errors</h2></div></div><div></div></div><p>
159 At this time there are many little surprises for the unwary administrator. In a real sense
160 it is imperative that every step of automated control scripts must be carefully tested
161 manually before putting them into active service.
162 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2921997"></a>Adding Groups Fails</h3></div></div><div></div></div><p>
163 This is a common problem when the <b class="command">groupadd</b> is called directly
164 by the Samba interface script for the <i class="parameter"><tt>add group script</tt></i> in
165 the <tt class="filename">smb.conf</tt> file.
167 The most common cause of failure is an attempt to add an MS Windows group account
168 that has either an upper case character and/or a space character in it.
170 There are three possible work-arounds. Firstly, use only group names that comply
171 with the limitations of the Unix/Linux <b class="command">groupadd</b> system tool.
172 The second involves use of the script mentioned earlier in this chapter, and the
173 third option is to manually create a Unix/Linux group account that can substitute
174 for the MS Windows group name, then use the procedure listed above to map that group
175 to the MS Windows group.
176 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2922057"></a>Adding MS Windows Groups to MS Windows Groups Fails</h3></div></div><div></div></div><p>
177 Samba-3 does NOT support nested groups from the MS Windows control environment.
178 </p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="passdb.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="optional.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="AccessControls.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 11. Account Information Databases </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 13. File, Directory and Share Access Controls</td></tr></table></div></body></html>