docs/docbook/projdoc/winbind.sgml

   1 <chapter id="winbind">
   2
   3
   4 <chapterinfo>
   5         <authorgroup>
   6         <author>
   7                 <firstname>Tim</firstname><surname>Potter</surname>
   8                 <affiliation>
   9                         <orgname>Samba Team</orgname>
  10                         <address><email>tpot@linuxcare.com.au</email></address>
  11                 </affiliation>
  12         </author>
  13         <author>
  14                 <firstname>Andrew</firstname><surname>Tridgell</surname>
  15                 <affiliation>
  16                         <orgname>Samba Team</orgname>
  17                         <address><email>tridge@linuxcare.com.au</email></address>
  18                 </affiliation>
  19         </author>
  20         <author>
  21                 <firstname>John</firstname><surname>Trostel</surname>
  22                 <affiliation>
  23                         <orgname>Snapserver</orgname>
  24                         <address><email>jtrostel@snapserver.com</email></address>
  25                 </affiliation>
  26         </author>
  27         <author>
  28                 <firstname>Naag</firstname><surname>Mummaneni</surname>
  29                 <affiliation>
  30                         <address><email>getnag@rediffmail.com</email></address>
  31                 </affiliation>
  32         </author>
  33         <author>
  34                 <firstname>Jelmer</firstname><surname>Vernooij</surname>
  35                 <affiliation>
  36                         <address><email>jelmer@nl.linux.org</email></address>
  37                 </affiliation>
  38         </author>
  39         </authorgroup>
  40         <pubdate>27 June 2002</pubdate>
  41 </chapterinfo>
  42
  43 <title>Unified Logons between Windows NT and UNIX using Winbind</title>
  44
  45 <sect1>
  46         <title>Abstract</title>
  47
  48         <para>Integration of UNIX and Microsoft Windows NT through
  49         a unified logon has been considered a "holy grail" in heterogeneous
  50         computing environments for a long time. We present
  51         <emphasis>winbind</emphasis>, a component of the Samba suite
  52         of programs as a solution to the unified logon problem. Winbind
  53         uses a UNIX implementation
  54         of Microsoft RPC calls, Pluggable Authentication Modules, and the Name
  55         Service Switch to allow Windows NT domain users to appear and operate
  56         as UNIX users on a UNIX machine. This paper describes the winbind
  57         system, explaining the functionality it provides, how it is configured,
  58         and how it works internally.</para>
  59 </sect1>
  60
  61
  62 <sect1>
  63         <title>Introduction</title>
  64
  65         <para>It is well known that UNIX and Microsoft Windows NT have
  66         different models for representing user and group information and
  67         use different technologies for implementing them. This fact has
  68         made it difficult to integrate the two systems in a satisfactory
  69         manner.</para>
  70
  71         <para>One common solution in use today has been to create
  72         identically named user accounts on both the UNIX and Windows systems
  73         and use the Samba suite of programs to provide file and print services
  74         between the two. This solution is far from perfect however, as
  75         adding and deleting users on both sets of machines becomes a chore
  76         and two sets of passwords are required both of which
  77         can lead to synchronization problems between the UNIX and Windows
  78         systems and confusion for users.</para>
  79
  80         <para>We divide the unified logon problem for UNIX machines into
  81         three smaller problems:</para>
  82
  83         <itemizedlist>
  84                 <listitem><para>Obtaining Windows NT user and group information
  85                 </para></listitem>
  86
  87                 <listitem><para>Authenticating Windows NT users
  88                 </para></listitem>
  89
  90                 <listitem><para>Password changing for Windows NT users
  91                 </para></listitem>
  92         </itemizedlist>
  93
  94
  95         <para>Ideally, a prospective solution to the unified logon problem
  96         would satisfy all the above components without duplication of
  97         information on the UNIX machines and without creating additional
  98         tasks for the system administrator when maintaining users and
  99         groups on either system. The winbind system provides a simple
 100         and elegant solution to all three components of the unified logon
 101         problem.</para>
 102 </sect1>
 103
 104
 105 <sect1>
 106         <title>What Winbind Provides</title>
 107
 108         <para>Winbind unifies UNIX and Windows NT account management by
 109         allowing a UNIX box to become a full member of a NT domain. Once
 110         this is done the UNIX box will see NT users and groups as if
 111         they were native UNIX users and groups, allowing the NT domain
 112         to be used in much the same manner that NIS+ is used within
 113         UNIX-only environments.</para>
 114
 115         <para>The end result is that whenever any
 116         program on the UNIX machine asks the operating system to lookup
 117         a user or group name, the query will be resolved by asking the
 118         NT domain controller for the specified domain to do the lookup.
 119         Because Winbind hooks into the operating system at a low level
 120         (via the NSS name resolution modules in the C library) this
 121         redirection to the NT domain controller is completely
 122         transparent.</para>
 123
 124         <para>Users on the UNIX machine can then use NT user and group
 125         names as they would use "native" UNIX names. They can chown files
 126         so that they are owned by NT domain users or even login to the
 127         UNIX machine and run a UNIX X-Window session as a domain user.</para>
 128
 129         <para>The only obvious indication that Winbind is being used is
 130         that user and group names take the form DOMAIN\user and
 131         DOMAIN\group. This is necessary as it allows Winbind to determine
 132         that redirection to a domain controller is wanted for a particular
 133         lookup and which trusted domain is being referenced.</para>
 134
 135         <para>Additionally, Winbind provides an authentication service
 136         that hooks into the Pluggable Authentication Modules (PAM) system
 137         to provide authentication via a NT domain to any PAM enabled
 138         applications. This capability solves the problem of synchronizing
 139         passwords between systems since all passwords are stored in a single
 140         location (on the domain controller).</para>
 141
 142         <sect2>
 143                 <title>Target Uses</title>
 144
 145                 <para>Winbind is targeted at organizations that have an
 146                 existing NT based domain infrastructure into which they wish
 147                 to put UNIX workstations or servers. Winbind will allow these
 148                 organizations to deploy UNIX workstations without having to
 149                 maintain a separate account infrastructure. This greatly
 150                 simplifies the administrative overhead of deploying UNIX
 151                 workstations into a NT based organization.</para>
 152
 153                 <para>Another interesting way in which we expect Winbind to
 154                 be used is as a central part of UNIX based appliances. Appliances
 155                 that provide file and print services to Microsoft based networks
 156                 will be able to use Winbind to provide seamless integration of
 157                 the appliance into the domain.</para>
 158         </sect2>
 159 </sect1>
 160
 161
 162
 163 <sect1>
 164         <title>How Winbind Works</title>
 165
 166         <para>The winbind system is designed around a client/server
 167         architecture. A long running <command>winbindd</command> daemon
 168         listens on a UNIX domain socket waiting for requests
 169         to arrive. These requests are generated by the NSS and PAM
 170         clients and processed sequentially.</para>
 171
 172         <para>The technologies used to implement winbind are described
 173         in detail below.</para>
 174
 175         <sect2>
 176                 <title>Microsoft Remote Procedure Calls</title>
 177
 178                 <para>Over the last two years, efforts have been underway
 179                 by various Samba Team members to decode various aspects of
 180                 the Microsoft Remote Procedure Call (MSRPC) system. This
 181                 system is used for most network related operations between
 182                 Windows NT machines including remote management, user authentication
 183                 and print spooling. Although initially this work was done
 184                 to aid the implementation of Primary Domain Controller (PDC)
 185                 functionality in Samba, it has also yielded a body of code which
 186                 can be used for other purposes.</para>
 187
 188                 <para>Winbind uses various MSRPC calls to enumerate domain users
 189                 and groups and to obtain detailed information about individual
 190                 users or groups. Other MSRPC calls can be used to authenticate
 191                 NT domain users and to change user passwords. By directly querying
 192                 a Windows PDC for user and group information, winbind maps the
 193                 NT account information onto UNIX user and group names.</para>
 194         </sect2>
 195
 196         <sect2>
 197                 <title>Name Service Switch</title>
 198
 199                 <para>The Name Service Switch, or NSS, is a feature that is
 200                 present in many UNIX operating systems. It allows system
 201                 information such as hostnames, mail aliases and user information
 202                 to be resolved from different sources. For example, a standalone
 203                 UNIX workstation may resolve system information from a series of
 204                 flat files stored on the local filesystem. A networked workstation
 205                 may first attempt to resolve system information from local files,
 206                 and then consult a NIS database for user information or a DNS server
 207                 for hostname information.</para>
 208
 209                 <para>The NSS application programming interface allows winbind
 210                 to present itself as a source of system information when
 211                 resolving UNIX usernames and groups.  Winbind uses this interface,
 212                 and information obtained from a Windows NT server using MSRPC
 213                 calls to provide a new source of account enumeration.  Using standard
 214                 UNIX library calls, one can enumerate the users and groups on
 215                 a UNIX machine running winbind and see all users and groups in
 216                 a NT domain plus any trusted domain as though they were local
 217                 users and groups.</para>
 218
 219                 <para>The primary control file for NSS is
 220                 <filename>/etc/nsswitch.conf</filename>.
 221                 When a UNIX application makes a request to do a lookup
 222                 the C library looks in <filename>/etc/nsswitch.conf</filename>
 223                 for a line which matches the service type being requested, for
 224                 example the "passwd" service type is used when user or group names
 225                 are looked up. This     config line species which implementations
 226                 of that service should be tried and in what order. If the passwd
 227                 config line is:</para>
 228
 229                 <para><command>passwd: files example</command></para>
 230
 231                 <para>then the C library will first load a module called
 232                 <filename>/lib/libnss_files.so</filename> followed by
 233                 the module <filename>/lib/libnss_example.so</filename>. The
 234                 C library will dynamically load each of these modules in turn
 235                 and call resolver functions within the modules to try to resolve
 236                 the request. Once the request is resolved the C library returns the
 237                 result to the application.</para>
 238
 239                 <para>This NSS interface provides a very easy way for Winbind
 240                 to hook into the operating system. All that needs to be done
 241                 is to put <filename>libnss_winbind.so</filename> in <filename>/lib/</filename>
 242                 then add "winbind" into <filename>/etc/nsswitch.conf</filename> at
 243                 the appropriate place. The C library will then call Winbind to
 244                 resolve user and group names.</para>
 245         </sect2>
 246
 247         <sect2>
 248                 <title>Pluggable Authentication Modules</title>
 249
 250                 <para>Pluggable Authentication Modules, also known as PAM,
 251                 is a system for abstracting authentication and authorization
 252                 technologies. With a PAM module it is possible to specify different
 253                 authentication methods for different system applications without
 254                 having to recompile these applications. PAM is also useful
 255                 for implementing a particular policy for authorization. For example,
 256                 a system administrator may only allow console logins from users
 257                 stored in the local password file but only allow users resolved from
 258                 a NIS database to log in over the network.</para>
 259
 260                 <para>Winbind uses the authentication management and password
 261                 management PAM interface to integrate Windows NT users into a
 262                 UNIX system. This allows Windows NT users to log in to a UNIX
 263                 machine and be authenticated against a suitable Primary Domain
 264                 Controller. These users can also change their passwords and have
 265                 this change take effect directly on the Primary Domain Controller.
 266                 </para>
 267
 268                 <para>PAM is configured by providing control files in the directory
 269                 <filename>/etc/pam.d/</filename> for each of the services that
 270                 require authentication. When an authentication request is made
 271                 by an application the PAM code in the C library looks up this
 272                 control file to determine what modules to load to do the
 273                 authentication check and in what order. This interface makes adding
 274                 a new authentication service for Winbind very easy, all that needs
 275                 to be done is that the <filename>pam_winbind.so</filename> module
 276                 is copied to <filename>/lib/security/</filename> and the PAM
 277                 control files for relevant services are updated to allow
 278                 authentication via winbind. See the PAM documentation
 279                 for more details.</para>
 280         </sect2>
 281
 282
 283         <sect2>
 284                 <title>User and Group ID Allocation</title>
 285
 286                 <para>When a user or group is created under Windows NT
 287                 is it allocated a numerical relative identifier (RID). This is
 288                 slightly different to UNIX which has a range of numbers that are
 289                 used to identify users, and the same range in which to identify
 290                 groups. It is winbind's job to convert RIDs to UNIX id numbers and
 291                 vice versa.  When winbind is configured it is given part of the UNIX
 292                 user id space and a part of the UNIX group id space in which to
 293                 store Windows NT users and groups. If a Windows NT user is
 294                 resolved for the first time, it is allocated the next UNIX id from
 295                 the range. The same process applies for Windows NT groups. Over
 296                 time, winbind will have mapped all Windows NT users and groups
 297                 to UNIX user ids and group ids.</para>
 298
 299                 <para>The results of this mapping are stored persistently in
 300                 an ID mapping database held in a tdb database). This ensures that
 301                 RIDs are mapped to UNIX IDs in a consistent way.</para>
 302         </sect2>
 303
 304
 305         <sect2>
 306                 <title>Result Caching</title>
 307
 308                 <para>An active system can generate a lot of user and group
 309                 name lookups. To reduce the network cost of these lookups winbind
 310                 uses a caching scheme based on the SAM sequence number supplied
 311                 by NT domain controllers.  User or group information returned
 312                 by a PDC is cached by winbind along with a sequence number also
 313                 returned by the PDC. This sequence number is incremented by
 314                 Windows NT whenever any user or group information is modified. If
 315                 a cached entry has expired, the sequence number is requested from
 316                 the PDC and compared against the sequence number of the cached entry.
 317                 If the sequence numbers do not match, then the cached information
 318                 is discarded and up to date information is requested directly
 319                 from the PDC.</para>
 320         </sect2>
 321 </sect1>
 322
 323
 324 <sect1>
 325         <title>Installation and Configuration</title>
 326
 327 <para>
 328 Many thanks to John Trostel <ulink
 329 url="mailto:jtrostel@snapserver.com">jtrostel@snapserver.com</ulink>
 330 for providing the HOWTO for this section.
 331 </para>
 332
 333 <para>
 334 This HOWTO describes how to get winbind services up and running
 335 to control access and authenticate users on your Linux box using
 336 the winbind services which come with SAMBA 2.2.2.
 337 </para>
 338
 339 <para>
 340 There is also some Solaris specific information in
 341 <filename>docs/textdocs/Solaris-Winbind-HOWTO.txt</filename>.
 342 Future revisions of this document will incorporate that
 343 information.
 344 </para>
 345
 346
 347
 348 <sect2>
 349 <title>Introduction</title>
 350
 351 <para>
 352 This HOWTO describes the procedures used to get winbind up and
 353 running on my RedHat 7.1 system.  Winbind is capable of providing access
 354 and authentication control for Windows Domain users through an NT
 355 or Win2K PDC for 'regular' services, such as telnet a nd ftp, as
 356 well for SAMBA services.
 357 </para>
 358
 359 <para>
 360 This HOWTO has been written from a 'RedHat-centric' perspective, so if
 361 you are using another distribution, you may have to modify the instructions
 362 somewhat to fit the way your distribution works.
 363 </para>
 364
 365
 366 <itemizedlist>
 367 <listitem>
 368         <para>
 369         <emphasis>Why should I to this?</emphasis>
 370         </para>
 371
 372         <para>This allows the SAMBA administrator to rely on the
 373         authentication mechanisms on the NT/Win2K PDC for the authentication
 374         of domain members.  NT/Win2K users no longer need to have separate
 375         accounts on the SAMBA server.
 376         </para>
 377 </listitem>
 378
 379 <listitem>
 380         <para>
 381         <emphasis>Who should be reading this document?</emphasis>
 382         </para>
 383
 384         <para>
 385         This HOWTO is designed for system administrators.  If you are
 386         implementing SAMBA on a file server and wish to (fairly easily)
 387         integrate existing NT/Win2K users from your PDC onto the
 388         SAMBA server, this HOWTO is for you.  That said, I am no NT or PAM
 389         expert, so you may find a better or easier way to accomplish
 390         these tasks.
 391         </para>
 392 </listitem>
 393 </itemizedlist>
 394 </sect2>
 395
 396
 397 <sect2>
 398 <title>Requirements</title>
 399
 400 <para>
 401 If you have a samba configuration file that you are currently
 402 using... <emphasis>BACK IT UP!</emphasis>  If your system already uses PAM,
 403 <emphasis>back up the <filename>/etc/pam.d</filename> directory
 404 contents!</emphasis> If you haven't already made a boot disk,
 405 <emphasis>MAKE ONE NOW!</emphasis>
 406 </para>
 407
 408 <para>
 409 Messing with the pam configuration files can make it nearly impossible
 410 to log in to yourmachine. That's why you want to be able to boot back
 411 into your machine in single user mode and restore your
 412 <filename>/etc/pam.d</filename> back to the original state they were in if
 413 you get frustrated with the way things are going.  ;-)
 414 </para>
 415
 416 <para>
 417 The latest version of SAMBA (version 3.0 as of this writing), now
 418 includes a functioning winbindd daemon.  Please refer to the
 419 <ulink url="http://samba.org/">main SAMBA web page</ulink> or,
 420 better yet, your closest SAMBA mirror site for instructions on
 421 downloading the source code.
 422 </para>
 423
 424 <para>
 425 To allow Domain users the ability to access SAMBA shares and
 426 files, as well as potentially other services provided by your
 427 SAMBA machine, PAM (pluggable authentication modules) must
 428 be setup properly on your machine.  In order to compile the
 429 winbind modules, you should have at least the pam libraries resident
 430 on your system.  For recent RedHat systems (7.1, for instance), that
 431 means <filename>pam-0.74-22</filename>.  For best results, it is helpful to also
 432 install the development packages in <filename>pam-devel-0.74-22</filename>.
 433 </para>
 434
 435 </sect2>
 436
 437
 438 <sect2>
 439 <title>Testing Things Out</title>
 440
 441 <para>
 442 Before starting, it is probably best to kill off all the SAMBA
 443 related daemons running on your server.  Kill off all <command>smbd</command>,
 444 <command>nmbd</command>, and <command>winbindd</command> processes that may
 445 be running.  To use PAM, you will want to make sure that you have the
 446 standard PAM package (for RedHat) which supplies the <filename>/etc/pam.d</filename>
 447 directory structure, including the pam modules are used by pam-aware
 448 services, several pam libraries, and the <filename>/usr/doc</filename>
 449 and <filename>/usr/man</filename> entries for pam.  Winbind built better
 450 in SAMBA if the pam-devel package was also installed.  This package includes
 451 the header files needed to compile pam-aware applications. For instance,
 452 my RedHat system has both <filename>pam-0.74-22</filename> and
 453 <filename>pam-devel-0.74-22</filename> RPMs installed.
 454 </para>
 455
 456 <sect3>
 457 <title>Configure and compile SAMBA</title>
 458
 459 <para>
 460 The configuration and compilation of SAMBA is pretty straightforward.
 461 The first three steps may not be necessary depending upon
 462 whether or not you have previously built the Samba binaries.
 463 </para>
 464
 465 <para><programlisting>
 466 <prompt>root#</prompt> <command>autoconf</command>
 467 <prompt>root#</prompt> <command>make clean</command>
 468 <prompt>root#</prompt> <command>rm config.cache</command>
 469 <prompt>root#</prompt> <command>./configure --with-winbind</command>
 470 <prompt>root#</prompt> <command>make</command>
 471 <prompt>root#</prompt> <command>make install</command>
 472 </programlisting></para>
 473
 474
 475 <para>
 476 This will, by default, install SAMBA in <filename>/usr/local/samba</filename>.
 477 See the main SAMBA documentation if you want to install SAMBA somewhere else.
 478 It will also build the winbindd executable and libraries.
 479 </para>
 480
 481 </sect3>
 482
 483 <sect3>
 484 <title>Configure <filename>nsswitch.conf</filename> and the
 485 winbind libraries</title>
 486
 487 <para>
 488 The libraries needed to run the <command>winbindd</command> daemon
 489 through nsswitch need to be copied to their proper locations, so
 490 </para>
 491
 492 <para>
 493 <prompt>root#</prompt> <command>cp ../samba/source/nsswitch/libnss_winbind.so /lib</command>
 494 </para>
 495
 496 <para>
 497 I also found it necessary to make the following symbolic link:
 498 </para>
 499
 500 <para>
 501 <prompt>root#</prompt> <command>ln -s /lib/libnss_winbind.so /lib/libnss_winbind.so.2</command>
 502 </para>
 503
 504 <para>And, in the case of Sun solaris:</para>
 505 <para>
 506 <prompt>root#</prompt> <command>ln -s /usr/lib/libnss_winbind.so /usr/lib/libnss_winbind.so.1</command>
 507 <prompt>root#</prompt> <command>ln -s /usr/lib/libnss_winbind.so /usr/lib/nss_winbind.so.1</command>
 508 <prompt>root#</prompt> <command>ln -s /usr/lib/libnss_winbind.so /usr/lib/nss_winbind.so.2</command>
 509 </para>
 510
 511 <para>
 512 Now, as root you need to edit <filename>/etc/nsswitch.conf</filename> to
 513 allow user and group entries to be visible from the <command>winbindd</command>
 514 daemon.  My <filename>/etc/nsswitch.conf</filename> file look like
 515 this after editing:
 516 </para>
 517
 518 <para><programlisting>
 519         passwd:     files winbind
 520         shadow:     files
 521         group:      files winbind
 522 </programlisting></para>
 523
 524 <para>
 525 The libraries needed by the winbind daemon will be automatically
 526 entered into the <command>ldconfig</command> cache the next time
 527 your system reboots, but it
 528 is faster (and you don't need to reboot) if you do it manually:
 529 </para>
 530
 531 <para>
 532 <prompt>root#</prompt> <command>/sbin/ldconfig -v | grep winbind</command>
 533 </para>
 534
 535 <para>
 536 This makes <filename>libnss_winbind</filename> available to winbindd
 537 and echos back a check to you.
 538 </para>
 539
 540 </sect3>
 541
 542
 543 <sect3>
 544 <title>Configure smb.conf</title>
 545
 546 <para>
 547 Several parameters are needed in the smb.conf file to control
 548 the behavior of <command>winbindd</command>. Configure
 549 <filename>smb.conf</filename> These are described in more detail in
 550 the <ulink url="winbindd.8.html">winbindd(8)</ulink> man page.  My
 551 <filename>smb.conf</filename> file was modified to
 552 include the following entries in the [global] section:
 553 </para>
 554
 555 <para><programlisting>
 556 [global]
 557      &lt;...&gt;
 558      # separate domain and username with '+', like DOMAIN+username
 559      <ulink url="winbindd.8.html#WINBINDSEPARATOR">winbind separator</ulink> = +
 560      # use uids from 10000 to 20000 for domain users
 561      <ulink url="winbindd.8.html#WINBINDUID">winbind uid</ulink> = 10000-20000
 562      # use gids from 10000 to 20000 for domain groups
 563      <ulink url="winbindd.8.html#WINBINDGID">winbind gid</ulink> = 10000-20000
 564      # allow enumeration of winbind users and groups
 565      <ulink url="winbindd.8.html#WINBINDENUMUSERS">winbind enum users</ulink> = yes
 566      <ulink url="winbindd.8.html#WINBINDENUMGROUP">winbind enum groups</ulink> = yes
 567      # give winbind users a real shell (only needed if they have telnet access)
 568      <ulink url="winbindd.8.html#TEMPLATEHOMEDIR">template homedir</ulink> = /home/winnt/%D/%U
 569      <ulink url="winbindd.8.html#TEMPLATESHELL">template shell</ulink> = /bin/bash
 570 </programlisting></para>
 571
 572 </sect3>
 573
 574
 575 <sect3>
 576 <title>Join the SAMBA server to the PDC domain</title>
 577
 578 <para>
 579 Enter the following command to make the SAMBA server join the
 580 PDC domain, where <replaceable>DOMAIN</replaceable> is the name of
 581 your Windows domain and <replaceable>Administrator</replaceable> is
 582 a domain user who has administrative privileges in the domain.
 583 </para>
 584
 585
 586 <para>
 587 <prompt>root#</prompt> <command>/usr/local/samba/bin/net rpc join -S PDC -U Administrator</command>
 588 </para>
 589
 590
 591 <para>
 592 The proper response to the command should be: "Joined the domain
 593 <replaceable>DOMAIN</replaceable>" where <replaceable>DOMAIN</replaceable>
 594 is your DOMAIN name.
 595 </para>
 596
 597 </sect3>
 598
 599
 600 <sect3>
 601 <title>Start up the winbindd daemon and test it!</title>
 602
 603 <para>
 604 Eventually, you will want to modify your smb startup script to
 605 automatically invoke the winbindd daemon when the other parts of
 606 SAMBA start, but it is possible to test out just the winbind
 607 portion first.  To start up winbind services, enter the following
 608 command as root:
 609 </para>
 610
 611 <para>
 612 <prompt>root#</prompt> <command>/usr/local/samba/bin/winbindd</command>
 613 </para>
 614
 615 <para>
 616 I'm always paranoid and like to make sure the daemon
 617 is really running...
 618 </para>
 619
 620 <para>
 621 <prompt>root#</prompt> <command>ps -ae | grep winbindd</command>
 622 </para>
 623 <para>
 624 This command should produce output like this, if the daemon is running
 625 </para>
 626 <para>
 627 3025 ?        00:00:00 winbindd
 628 </para>
 629
 630 <para>
 631 Now... for the real test, try to get some information about the
 632 users on your PDC
 633 </para>
 634
 635 <para>
 636 <prompt>root#</prompt> <command>/usr/local/samba/bin/wbinfo -u</command>
 637 </para>
 638
 639 <para>
 640 This should echo back a list of users on your Windows users on
 641 your PDC.  For example, I get the following response:
 642 </para>
 643
 644 <para><programlisting>
 645 CEO+Administrator
 646 CEO+burdell
 647 CEO+Guest
 648 CEO+jt-ad
 649 CEO+krbtgt
 650 CEO+TsInternetUser
 651 </programlisting></para>
 652
 653 <para>
 654 Obviously, I have named my domain 'CEO' and my <parameter>winbind
 655 separator</parameter> is '+'.
 656 </para>
 657
 658 <para>
 659 You can do the same sort of thing to get group information from
 660 the PDC:
 661 </para>
 662
 663 <para><programlisting>
 664 <prompt>root#</prompt> <command>/usr/local/samba/bin/wbinfo -g</command>
 665 CEO+Domain Admins
 666 CEO+Domain Users
 667 CEO+Domain Guests
 668 CEO+Domain Computers
 669 CEO+Domain Controllers
 670 CEO+Cert Publishers
 671 CEO+Schema Admins
 672 CEO+Enterprise Admins
 673 CEO+Group Policy Creator Owners
 674 </programlisting></para>
 675
 676 <para>
 677 The function 'getent' can now be used to get unified
 678 lists of both local and PDC users and groups.
 679 Try the following command:
 680 </para>
 681
 682 <para>
 683 <prompt>root#</prompt> <command>getent passwd</command>
 684 </para>
 685
 686 <para>
 687 You should get a list that looks like your <filename>/etc/passwd</filename>
 688 list followed by the domain users with their new uids, gids, home
 689 directories and default shells.
 690 </para>
 691
 692 <para>
 693 The same thing can be done for groups with the command
 694 </para>
 695
 696 <para>
 697 <prompt>root#</prompt> <command>getent group</command>
 698 </para>
 699
 700 </sect3>
 701
 702
 703 <sect3>
 704 <title>Fix the init.d startup scripts</title>
 705
 706 <sect4>
 707 <title>Linux</title>
 708
 709 <para>
 710 The <command>winbindd</command> daemon needs to start up after the
 711 <command>smbd</command> and <command>nmbd</command> daemons are running.
 712 To accomplish this task, you need to modify the startup scripts of your system. They are located at <filename>/etc/init.d/smb</filename> in RedHat and
 713 <filename>/etc/init.d/samba</filename> in Debian.
 714 script to add commands to invoke this daemon in the proper sequence.  My
 715 startup script starts up <command>smbd</command>,
 716 <command>nmbd</command>, and <command>winbindd</command> from the
 717 <filename>/usr/local/samba/bin</filename> directory directly.  The 'start'
 718 function in the script looks like this:
 719 </para>
 720
 721 <para><programlisting>
 722 start() {
 723         KIND="SMB"
 724         echo -n $"Starting $KIND services: "
 725         daemon /usr/local/samba/bin/smbd $SMBDOPTIONS
 726         RETVAL=$?
 727         echo
 728         KIND="NMB"
 729         echo -n $"Starting $KIND services: "
 730         daemon /usr/local/samba/bin/nmbd $NMBDOPTIONS
 731         RETVAL2=$?
 732         echo
 733         KIND="Winbind"
 734         echo -n $"Starting $KIND services: "
 735         daemon /usr/local/samba/bin/winbindd
 736         RETVAL3=$?
 737         echo
 738         [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] &amp;&amp; touch /var/lock/subsys/smb || \
 739            RETVAL=1
 740         return $RETVAL
 741 }
 742 </programlisting></para>
 743
 744 <para>
 745 The 'stop' function has a corresponding entry to shut down the
 746 services and look s like this:
 747 </para>
 748
 749 <para><programlisting>
 750 stop() {
 751         KIND="SMB"
 752         echo -n $"Shutting down $KIND services: "
 753         killproc smbd
 754         RETVAL=$?
 755         echo
 756         KIND="NMB"
 757         echo -n $"Shutting down $KIND services: "
 758         killproc nmbd
 759         RETVAL2=$?
 760         echo
 761         KIND="Winbind"
 762         echo -n $"Shutting down $KIND services: "
 763         killproc winbindd
 764         RETVAL3=$?
 765         [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] &amp;&amp; rm -f /var/lock/subsys/smb
 766         echo ""
 767         return $RETVAL
 768 }
 769 </programlisting></para>
 770 </sect4>
 771
 772 <sect4>
 773 <title>Solaris</title>
 774
 775 <para>On solaris, you need to modify the
 776 <filename>/etc/init.d/samba.server</filename> startup script. It usually
 777 only starts smbd and nmbd but should now start winbindd too. If you
 778 have samba installed in <filename>/usr/local/samba/bin</filename>,
 779 the file could contains something like this:
 780 </para>
 781
 782 <para><programlisting>
 783 ##
 784 ## samba.server
 785 ##
 786
 787 if [ ! -d /usr/bin ]
 788 then                    # /usr not mounted
 789         exit
 790 fi
 791
 792 killproc() {            # kill the named process(es)
 793         pid=`/usr/bin/ps -e |
 794              /usr/bin/grep -w $1 |
 795              /usr/bin/sed -e 's/^  *//' -e 's/ .*//'`
 796         [ "$pid" != "" ] &amp;&amp; kill $pid
 797 }
 798
 799 # Start/stop processes required for samba server
 800
 801 case "$1" in
 802
 803 'start')
 804 #
 805 # Edit these lines to suit your installation (paths, workgroup, host)
 806 #
 807 echo Starting SMBD
 808    /usr/local/samba/bin/smbd -D -s \
 809         /usr/local/samba/smb.conf
 810
 811 echo Starting NMBD
 812    /usr/local/samba/bin/nmbd -D -l \
 813         /usr/local/samba/var/log -s /usr/local/samba/smb.conf
 814
 815 echo Starting Winbind Daemon
 816    /usr/local/samba/bin/winbindd
 817    ;;
 818
 819 'stop')
 820    killproc nmbd
 821    killproc smbd
 822    killproc winbindd
 823    ;;
 824
 825 *)
 826    echo "Usage: /etc/init.d/samba.server { start | stop }"
 827    ;;
 828 esac
 829 </programlisting></para>
 830 </sect4>
 831
 832 <sect4>
 833 <title>Restarting</title>
 834 <para>
 835 If you restart the <command>smbd</command>, <command>nmbd</command>,
 836 and <command>winbindd</command> daemons at this point, you
 837 should be able to connect to the samba server as a domain member just as
 838 if you were a local user.
 839 </para>
 840 </sect4>
 841 </sect3>
 842
 843 <sect3>
 844 <title>Configure Winbind and PAM</title>
 845
 846 <para>
 847 If you have made it this far, you know that winbindd and samba are working
 848 together.  If you want to use winbind to provide authentication for other
 849 services, keep reading.  The pam configuration files need to be altered in
 850 this step.  (Did you remember to make backups of your original
 851 <filename>/etc/pam.d</filename> files? If not, do it now.)
 852 </para>
 853
 854 <para>
 855 You will need a pam module to use winbindd with these other services.  This
 856 module will be compiled in the <filename>../source/nsswitch</filename> directory
 857 by invoking the command
 858 </para>
 859
 860 <para>
 861 <prompt>root#</prompt> <command>make nsswitch/pam_winbind.so</command>
 862 </para>
 863
 864 <para>
 865 from the <filename>../source</filename> directory.  The
 866 <filename>pam_winbind.so</filename> file should be copied to the location of
 867 your other pam security modules.  On my RedHat system, this was the
 868 <filename>/lib/security</filename> directory. On Solaris, the pam security
 869 modules reside in <filename>/usr/lib/security</filename>.
 870 </para>
 871
 872 <para>
 873 <prompt>root#</prompt> <command>cp ../samba/source/nsswitch/pam_winbind.so /lib/security</command>
 874 </para>
 875
 876 <sect4>
 877 <title>Linux/FreeBSD-specific PAM configuration</title>
 878
 879 <para>
 880 The <filename>/etc/pam.d/samba</filename> file does not need to be changed. I
 881 just left this fileas it was:
 882 </para>
 883
 884
 885 <para><programlisting>
 886 auth    required        /lib/security/pam_stack.so service=system-auth
 887 account required        /lib/security/pam_stack.so service=system-auth
 888 </programlisting></para>
 889
 890 <para>
 891 The other services that I modified to allow the use of winbind
 892 as an authentication service were the normal login on the console (or a terminal
 893 session), telnet logins, and ftp service.  In order to enable these
 894 services, you may first need to change the entries in
 895 <filename>/etc/xinetd.d</filename> (or <filename>/etc/inetd.conf</filename>).
 896 RedHat 7.1 uses the new xinetd.d structure, in this case you need
 897 to change the lines in <filename>/etc/xinetd.d/telnet</filename>
 898 and <filename>/etc/xinetd.d/wu-ftp</filename> from
 899 </para>
 900
 901 <para><programlisting>
 902 enable = no
 903 </programlisting></para>
 904
 905 <para>
 906 to
 907 </para>
 908
 909 <para><programlisting>
 910 enable = yes
 911 </programlisting></para>
 912
 913 <para>
 914 For ftp services to work properly, you will also need to either
 915 have individual directories for the domain users already present on
 916 the server, or change the home directory template to a general
 917 directory for all domain users.  These can be easily set using
 918 the <filename>smb.conf</filename> global entry
 919 <command>template homedir</command>.
 920 </para>
 921
 922 <para>
 923 The <filename>/etc/pam.d/ftp</filename> file can be changed
 924 to allow winbind ftp access in a manner similar to the
 925 samba file.  My <filename>/etc/pam.d/ftp</filename> file was
 926 changed to look like this:
 927 </para>
 928
 929 <para><programlisting>
 930 auth       required     /lib/security/pam_listfile.so item=user sense=deny file=/etc/ftpusers onerr=succeed
 931 auth       sufficient   /lib/security/pam_winbind.so
 932 auth       required     /lib/security/pam_stack.so service=system-auth
 933 auth       required     /lib/security/pam_shells.so
 934 account    sufficient   /lib/security/pam_winbind.so
 935 account    required     /lib/security/pam_stack.so service=system-auth
 936 session    required     /lib/security/pam_stack.so service=system-auth
 937 </programlisting></para>
 938
 939 <para>
 940 The <filename>/etc/pam.d/login</filename> file can be changed nearly the
 941 same way.  It now looks like this:
 942 </para>
 943
 944 <para><programlisting>
 945 auth       required     /lib/security/pam_securetty.so
 946 auth       sufficient   /lib/security/pam_winbind.so
 947 auth       sufficient   /lib/security/pam_unix.so use_first_pass
 948 auth       required     /lib/security/pam_stack.so service=system-auth
 949 auth       required     /lib/security/pam_nologin.so
 950 account    sufficient   /lib/security/pam_winbind.so
 951 account    required     /lib/security/pam_stack.so service=system-auth
 952 password   required     /lib/security/pam_stack.so service=system-auth
 953 session    required     /lib/security/pam_stack.so service=system-auth
 954 session    optional     /lib/security/pam_console.so
 955 </programlisting></para>
 956
 957 <para>
 958 In this case, I added the <command>auth sufficient /lib/security/pam_winbind.so</command>
 959 lines as before, but also added the <command>required pam_securetty.so</command>
 960 above it, to disallow root logins over the network.  I also added a
 961 <command>sufficient /lib/security/pam_unix.so use_first_pass</command>
 962 line after the <command>winbind.so</command> line to get rid of annoying
 963 double prompts for passwords.
 964 </para>
 965
 966 </sect4>
 967
 968 <sect4>
 969 <title>Solaris-specific configuration</title>
 970
 971 <para>
 972 The /etc/pam.conf needs to be changed. I changed this file so that my Domain
 973 users can logon both locally as well as telnet.The following are the changes
 974 that I made.You can customize the pam.conf file as per your requirements,but
 975 be sure of those changes because in the worst case it will leave your system
 976 nearly impossible to boot.
 977 </para>
 978
 979 <para><programlisting>
 980 #
 981 #ident  "@(#)pam.conf   1.14    99/09/16 SMI"
 982 #
 983 # Copyright (c) 1996-1999, Sun Microsystems, Inc.
 984 # All Rights Reserved.
 985 #
 986 # PAM configuration
 987 #
 988 # Authentication management
 989 #
 990 login   auth required   /usr/lib/security/pam_winbind.so
 991 login   auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
 992 login   auth required   /usr/lib/security/$ISA/pam_dial_auth.so.1 try_first_pass
 993 #
 994 rlogin  auth sufficient /usr/lib/security/pam_winbind.so
 995 rlogin  auth sufficient /usr/lib/security/$ISA/pam_rhosts_auth.so.1
 996 rlogin  auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
 997 #
 998 dtlogin auth sufficient /usr/lib/security/pam_winbind.so
 999 dtlogin auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
1000 #
1001 rsh     auth required   /usr/lib/security/$ISA/pam_rhosts_auth.so.1
1002 other   auth sufficient /usr/lib/security/pam_winbind.so
1003 other   auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
1004 #
1005 # Account management
1006 #
1007 login   account sufficient      /usr/lib/security/pam_winbind.so
1008 login   account requisite       /usr/lib/security/$ISA/pam_roles.so.1
1009 login   account required        /usr/lib/security/$ISA/pam_unix.so.1
1010 #
1011 dtlogin account sufficient      /usr/lib/security/pam_winbind.so
1012 dtlogin account requisite       /usr/lib/security/$ISA/pam_roles.so.1
1013 dtlogin account required        /usr/lib/security/$ISA/pam_unix.so.1
1014 #
1015 other   account sufficient      /usr/lib/security/pam_winbind.so
1016 other   account requisite       /usr/lib/security/$ISA/pam_roles.so.1
1017 other   account required        /usr/lib/security/$ISA/pam_unix.so.1
1018 #
1019 # Session management
1020 #
1021 other   session required        /usr/lib/security/$ISA/pam_unix.so.1
1022 #
1023 # Password management
1024 #
1025 #other   password sufficient     /usr/lib/security/pam_winbind.so
1026 other   password required       /usr/lib/security/$ISA/pam_unix.so.1
1027 dtsession auth required /usr/lib/security/$ISA/pam_unix.so.1
1028 #
1029 # Support for Kerberos V5 authentication (uncomment to use Kerberos)
1030 #
1031 #rlogin auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1032 #login  auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1033 #dtlogin        auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1034 #other  auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1035 #dtlogin        account optional /usr/lib/security/$ISA/pam_krb5.so.1
1036 #other  account optional /usr/lib/security/$ISA/pam_krb5.so.1
1037 #other  session optional /usr/lib/security/$ISA/pam_krb5.so.1
1038 #other  password optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1039 </programlisting></para>
1040
1041 <para>
1042 I also added a try_first_pass line after the winbind.so line to get rid of
1043 annoying double prompts for passwords.
1044 </para>
1045
1046 <para>
1047 Now restart your Samba and try connecting through your application that you
1048 configured in the pam.conf.
1049 </para>
1050
1051 </sect4>
1052
1053 </sect3>
1054
1055 </sect2>
1056
1057 </sect1>
1058
1059 <sect1>
1060         <title>Limitations</title>
1061
1062         <para>Winbind has a number of limitations in its current
1063         released version that we hope to overcome in future
1064         releases:</para>
1065
1066         <itemizedlist>
1067                 <listitem><para>Winbind is currently only available for
1068                 the Linux operating system, although ports to other operating
1069                 systems are certainly possible. For such ports to be feasible,
1070                 we require the C library of the target operating system to
1071                 support the Name Service Switch and Pluggable Authentication
1072                 Modules systems. This is becoming more common as NSS and
1073                 PAM gain        support among UNIX vendors.</para></listitem>
1074
1075                 <listitem><para>The mappings of Windows NT RIDs to UNIX ids
1076                 is not made algorithmically and depends on the order in which
1077                 unmapped users or groups are seen by winbind. It may be difficult
1078                 to recover the mappings of rid to UNIX id mapping if the file
1079                 containing this information is corrupted or destroyed.</para>
1080                 </listitem>
1081
1082                 <listitem><para>Currently the winbind PAM module does not take
1083                 into account possible workstation and logon time restrictions
1084                 that may be been set for Windows NT users.</para></listitem>
1085         </itemizedlist>
1086 </sect1>
1087
1088
1089 <sect1>
1090         <title>Conclusion</title>
1091
1092         <para>The winbind system, through the use of the Name Service
1093         Switch, Pluggable Authentication Modules, and appropriate
1094         Microsoft RPC calls have allowed us to provide seamless
1095         integration of Microsoft Windows NT domain users on a
1096         UNIX system. The result is a great reduction in the administrative
1097         cost of running a mixed UNIX and NT network.</para>
1098
1099 </sect1>
1100
1101 </chapter>