docs/docbook/projdoc/winbind.sgml

   1 <chapter id="winbind">
   2
   3 <chapterinfo>
   4         <authorgroup>
   5         <author>
   6                 <firstname>Tim</firstname><surname>Potter</surname>
   7                 <affiliation>
   8                         <orgname>Samba Team</orgname>
   9                         <address><email>tpot@linuxcare.com.au</email></address>
  10                 </affiliation>
  11         </author>
  12         &author.tridge;
  13         &author.jht;
  14         <author>
  15                 <firstname>Naag</firstname><surname>Mummaneni</surname>
  16                 <affiliation>
  17                         <address><email>getnag@rediffmail.com</email></address>
  18                 </affiliation>
  19         </author>
  20         &author.jelmer;
  21         &author.jht;
  22         </authorgroup>
  23         <pubdate>27 June 2002</pubdate>
  24 </chapterinfo>
  25
  26 <title>Unified Logons between Windows NT and UNIX using Winbind</title>
  27
  28 <sect1>
  29         <title>Abstract</title>
  30
  31         <para>Integration of UNIX and Microsoft Windows NT through
  32         a unified logon has been considered a "holy grail" in heterogeneous
  33         computing environments for a long time. We present
  34         <emphasis>winbind</emphasis>, a component of the Samba suite
  35         of programs as a solution to the unified logon problem. Winbind
  36         uses a UNIX implementation
  37         of Microsoft RPC calls, Pluggable Authentication Modules, and the Name
  38         Service Switch to allow Windows NT domain users to appear and operate
  39         as UNIX users on a UNIX machine. This paper describes the winbind
  40         system, explaining the functionality it provides, how it is configured,
  41         and how it works internally.</para>
  42 </sect1>
  43
  44
  45 <sect1>
  46         <title>Introduction</title>
  47
  48         <para>It is well known that UNIX and Microsoft Windows NT have
  49         different models for representing user and group information and
  50         use different technologies for implementing them. This fact has
  51         made it difficult to integrate the two systems in a satisfactory
  52         manner.</para>
  53
  54         <para>One common solution in use today has been to create
  55         identically named user accounts on both the UNIX and Windows systems
  56         and use the Samba suite of programs to provide file and print services
  57         between the two. This solution is far from perfect however, as
  58         adding and deleting users on both sets of machines becomes a chore
  59         and two sets of passwords are required both of which
  60         can lead to synchronization problems between the UNIX and Windows
  61         systems and confusion for users.</para>
  62
  63         <para>We divide the unified logon problem for UNIX machines into
  64         three smaller problems:</para>
  65
  66         <itemizedlist>
  67                 <listitem><para>Obtaining Windows NT user and group information
  68                 </para></listitem>
  69
  70                 <listitem><para>Authenticating Windows NT users
  71                 </para></listitem>
  72
  73                 <listitem><para>Password changing for Windows NT users
  74                 </para></listitem>
  75         </itemizedlist>
  76
  77
  78         <para>Ideally, a prospective solution to the unified logon problem
  79         would satisfy all the above components without duplication of
  80         information on the UNIX machines and without creating additional
  81         tasks for the system administrator when maintaining users and
  82         groups on either system. The winbind system provides a simple
  83         and elegant solution to all three components of the unified logon
  84         problem.</para>
  85 </sect1>
  86
  87
  88 <sect1>
  89         <title>What Winbind Provides</title>
  90
  91         <para>Winbind unifies UNIX and Windows NT account management by
  92         allowing a UNIX box to become a full member of a NT domain. Once
  93         this is done the UNIX box will see NT users and groups as if
  94         they were native UNIX users and groups, allowing the NT domain
  95         to be used in much the same manner that NIS+ is used within
  96         UNIX-only environments.</para>
  97
  98         <para>The end result is that whenever any
  99         program on the UNIX machine asks the operating system to lookup
 100         a user or group name, the query will be resolved by asking the
 101         NT domain controller for the specified domain to do the lookup.
 102         Because Winbind hooks into the operating system at a low level
 103         (via the NSS name resolution modules in the C library) this
 104         redirection to the NT domain controller is completely
 105         transparent.</para>
 106
 107         <para>Users on the UNIX machine can then use NT user and group
 108         names as they would use "native" UNIX names. They can chown files
 109         so that they are owned by NT domain users or even login to the
 110         UNIX machine and run a UNIX X-Window session as a domain user.</para>
 111
 112         <para>The only obvious indication that Winbind is being used is
 113         that user and group names take the form DOMAIN\user and
 114         DOMAIN\group. This is necessary as it allows Winbind to determine
 115         that redirection to a domain controller is wanted for a particular
 116         lookup and which trusted domain is being referenced.</para>
 117
 118         <para>Additionally, Winbind provides an authentication service
 119         that hooks into the Pluggable Authentication Modules (PAM) system
 120         to provide authentication via a NT domain to any PAM enabled
 121         applications. This capability solves the problem of synchronizing
 122         passwords between systems since all passwords are stored in a single
 123         location (on the domain controller).</para>
 124
 125         <sect2>
 126                 <title>Target Uses</title>
 127
 128                 <para>Winbind is targeted at organizations that have an
 129                 existing NT based domain infrastructure into which they wish
 130                 to put UNIX workstations or servers. Winbind will allow these
 131                 organizations to deploy UNIX workstations without having to
 132                 maintain a separate account infrastructure. This greatly
 133                 simplifies the administrative overhead of deploying UNIX
 134                 workstations into a NT based organization.</para>
 135
 136                 <para>Another interesting way in which we expect Winbind to
 137                 be used is as a central part of UNIX based appliances. Appliances
 138                 that provide file and print services to Microsoft based networks
 139                 will be able to use Winbind to provide seamless integration of
 140                 the appliance into the domain.</para>
 141         </sect2>
 142 </sect1>
 143
 144
 145
 146 <sect1>
 147         <title>How Winbind Works</title>
 148
 149         <para>The winbind system is designed around a client/server
 150         architecture. A long running <command>winbindd</command> daemon
 151         listens on a UNIX domain socket waiting for requests
 152         to arrive. These requests are generated by the NSS and PAM
 153         clients and processed sequentially.</para>
 154
 155         <para>The technologies used to implement winbind are described
 156         in detail below.</para>
 157
 158         <sect2>
 159                 <title>Microsoft Remote Procedure Calls</title>
 160
 161                 <para>Over the last few years, efforts have been underway
 162                 by various Samba Team members to decode various aspects of
 163                 the Microsoft Remote Procedure Call (MSRPC) system. This
 164                 system is used for most network related operations between
 165                 Windows NT machines including remote management, user authentication
 166                 and print spooling. Although initially this work was done
 167                 to aid the implementation of Primary Domain Controller (PDC)
 168                 functionality in Samba, it has also yielded a body of code which
 169                 can be used for other purposes.</para>
 170
 171                 <para>Winbind uses various MSRPC calls to enumerate domain users
 172                 and groups and to obtain detailed information about individual
 173                 users or groups. Other MSRPC calls can be used to authenticate
 174                 NT domain users and to change user passwords. By directly querying
 175                 a Windows PDC for user and group information, winbind maps the
 176                 NT account information onto UNIX user and group names.</para>
 177         </sect2>
 178
 179         <sect2>
 180                 <title>Microsoft Active Directory Services</title>
 181
 182                 <para>
 183                 Since late 2001, Samba has gained the ability to
 184                 interact with Microsoft Windows 2000 using its 'Native
 185                 Mode' protocols, rather than the NT4 RPC services.
 186                 Using LDAP and Kerberos, a domain member running
 187                 winbind can enumerate users and groups in exactly the
 188                 same way as a Win2k client would, and in so doing
 189                 provide a much more efficient and
 190                 effective winbind implementation.
 191                 </para>
 192         </sect2>
 193
 194         <sect2>
 195                 <title>Name Service Switch</title>
 196
 197                 <para>The Name Service Switch, or NSS, is a feature that is
 198                 present in many UNIX operating systems. It allows system
 199                 information such as hostnames, mail aliases and user information
 200                 to be resolved from different sources. For example, a standalone
 201                 UNIX workstation may resolve system information from a series of
 202                 flat files stored on the local filesystem. A networked workstation
 203                 may first attempt to resolve system information from local files,
 204                 and then consult a NIS database for user information or a DNS server
 205                 for hostname information.</para>
 206
 207                 <para>The NSS application programming interface allows winbind
 208                 to present itself as a source of system information when
 209                 resolving UNIX usernames and groups.  Winbind uses this interface,
 210                 and information obtained from a Windows NT server using MSRPC
 211                 calls to provide a new source of account enumeration.  Using standard
 212                 UNIX library calls, one can enumerate the users and groups on
 213                 a UNIX machine running winbind and see all users and groups in
 214                 a NT domain plus any trusted domain as though they were local
 215                 users and groups.</para>
 216
 217                 <para>The primary control file for NSS is
 218                 <filename>/etc/nsswitch.conf</filename>.
 219                 When a UNIX application makes a request to do a lookup
 220                 the C library looks in <filename>/etc/nsswitch.conf</filename>
 221                 for a line which matches the service type being requested, for
 222                 example the "passwd" service type is used when user or group names
 223                 are looked up. This     config line species which implementations
 224                 of that service should be tried and in what order. If the passwd
 225                 config line is:</para>
 226
 227                 <para><command>passwd: files example</command></para>
 228
 229                 <para>then the C library will first load a module called
 230                 <filename>/lib/libnss_files.so</filename> followed by
 231                 the module <filename>/lib/libnss_example.so</filename>. The
 232                 C library will dynamically load each of these modules in turn
 233                 and call resolver functions within the modules to try to resolve
 234                 the request. Once the request is resolved the C library returns the
 235                 result to the application.</para>
 236
 237                 <para>This NSS interface provides a very easy way for Winbind
 238                 to hook into the operating system. All that needs to be done
 239                 is to put <filename>libnss_winbind.so</filename> in <filename>/lib/</filename>
 240                 then add "winbind" into <filename>/etc/nsswitch.conf</filename> at
 241                 the appropriate place. The C library will then call Winbind to
 242                 resolve user and group names.</para>
 243         </sect2>
 244
 245         <sect2>
 246                 <title>Pluggable Authentication Modules</title>
 247
 248                 <para>Pluggable Authentication Modules, also known as PAM,
 249                 is a system for abstracting authentication and authorization
 250                 technologies. With a PAM module it is possible to specify different
 251                 authentication methods for different system applications without
 252                 having to recompile these applications. PAM is also useful
 253                 for implementing a particular policy for authorization. For example,
 254                 a system administrator may only allow console logins from users
 255                 stored in the local password file but only allow users resolved from
 256                 a NIS database to log in over the network.</para>
 257
 258                 <para>Winbind uses the authentication management and password
 259                 management PAM interface to integrate Windows NT users into a
 260                 UNIX system. This allows Windows NT users to log in to a UNIX
 261                 machine and be authenticated against a suitable Primary Domain
 262                 Controller. These users can also change their passwords and have
 263                 this change take effect directly on the Primary Domain Controller.
 264                 </para>
 265
 266                 <para>PAM is configured by providing control files in the directory
 267                 <filename>/etc/pam.d/</filename> for each of the services that
 268                 require authentication. When an authentication request is made
 269                 by an application the PAM code in the C library looks up this
 270                 control file to determine what modules to load to do the
 271                 authentication check and in what order. This interface makes adding
 272                 a new authentication service for Winbind very easy, all that needs
 273                 to be done is that the <filename>pam_winbind.so</filename> module
 274                 is copied to <filename>/lib/security/</filename> and the PAM
 275                 control files for relevant services are updated to allow
 276                 authentication via winbind. See the PAM documentation
 277                 for more details.</para>
 278         </sect2>
 279
 280
 281         <sect2>
 282                 <title>User and Group ID Allocation</title>
 283
 284                 <para>When a user or group is created under Windows NT
 285                 is it allocated a numerical relative identifier (RID). This is
 286                 slightly different to UNIX which has a range of numbers that are
 287                 used to identify users, and the same range in which to identify
 288                 groups. It is winbind's job to convert RIDs to UNIX id numbers and
 289                 vice versa.  When winbind is configured it is given part of the UNIX
 290                 user id space and a part of the UNIX group id space in which to
 291                 store Windows NT users and groups. If a Windows NT user is
 292                 resolved for the first time, it is allocated the next UNIX id from
 293                 the range. The same process applies for Windows NT groups. Over
 294                 time, winbind will have mapped all Windows NT users and groups
 295                 to UNIX user ids and group ids.</para>
 296
 297                 <para>The results of this mapping are stored persistently in
 298                 an ID mapping database held in a tdb database). This ensures that
 299                 RIDs are mapped to UNIX IDs in a consistent way.</para>
 300         </sect2>
 301
 302
 303         <sect2>
 304                 <title>Result Caching</title>
 305
 306                 <para>An active system can generate a lot of user and group
 307                 name lookups. To reduce the network cost of these lookups winbind
 308                 uses a caching scheme based on the SAM sequence number supplied
 309                 by NT domain controllers.  User or group information returned
 310                 by a PDC is cached by winbind along with a sequence number also
 311                 returned by the PDC. This sequence number is incremented by
 312                 Windows NT whenever any user or group information is modified. If
 313                 a cached entry has expired, the sequence number is requested from
 314                 the PDC and compared against the sequence number of the cached entry.
 315                 If the sequence numbers do not match, then the cached information
 316                 is discarded and up to date information is requested directly
 317                 from the PDC.</para>
 318         </sect2>
 319 </sect1>
 320
 321
 322 <sect1>
 323         <title>Installation and Configuration</title>
 324
 325 <para>
 326 Many thanks to John Trostel <ulink
 327 url="mailto:jtrostel@snapserver.com">jtrostel@snapserver.com</ulink>
 328 for providing the HOWTO for this section.
 329 </para>
 330
 331 <para>
 332 This HOWTO describes how to get winbind services up and running
 333 to control access and authenticate users on your Linux box using
 334 the winbind services which come with SAMBA 2.2.2.
 335 </para>
 336
 337 <sect2>
 338 <title>Introduction</title>
 339
 340 <para>
 341 This HOWTO describes the procedures used to get winbind up and
 342 running on my RedHat 7.1 system.  Winbind is capable of providing access
 343 and authentication control for Windows Domain users through an NT
 344 or Win2K PDC for 'regular' services, such as telnet a nd ftp, as
 345 well for SAMBA services.
 346 </para>
 347
 348 <para>
 349 This HOWTO has been written from a 'RedHat-centric' perspective, so if
 350 you are using another distribution, you may have to modify the instructions
 351 somewhat to fit the way your distribution works.
 352 </para>
 353
 354
 355 <itemizedlist>
 356 <listitem>
 357         <para>
 358         <emphasis>Why should I to this?</emphasis>
 359         </para>
 360
 361         <para>This allows the SAMBA administrator to rely on the
 362         authentication mechanisms on the NT/Win2K PDC for the authentication
 363         of domain members.  NT/Win2K users no longer need to have separate
 364         accounts on the SAMBA server.
 365         </para>
 366 </listitem>
 367
 368 <listitem>
 369         <para>
 370         <emphasis>Who should be reading this document?</emphasis>
 371         </para>
 372
 373         <para>
 374         This HOWTO is designed for system administrators.  If you are
 375         implementing SAMBA on a file server and wish to (fairly easily)
 376         integrate existing NT/Win2K users from your PDC onto the
 377         SAMBA server, this HOWTO is for you.  That said, I am no NT or PAM
 378         expert, so you may find a better or easier way to accomplish
 379         these tasks.
 380         </para>
 381 </listitem>
 382 </itemizedlist>
 383 </sect2>
 384
 385
 386 <sect2>
 387 <title>Requirements</title>
 388
 389 <para>
 390 If you have a samba configuration file that you are currently
 391 using... <emphasis>BACK IT UP!</emphasis>  If your system already uses PAM,
 392 <emphasis>back up the <filename>/etc/pam.d</filename> directory
 393 contents!</emphasis> If you haven't already made a boot disk,
 394 <emphasis>MAKE ONE NOW!</emphasis>
 395 </para>
 396
 397 <para>
 398 Messing with the pam configuration files can make it nearly impossible
 399 to log in to yourmachine. That's why you want to be able to boot back
 400 into your machine in single user mode and restore your
 401 <filename>/etc/pam.d</filename> back to the original state they were in if
 402 you get frustrated with the way things are going.  ;-)
 403 </para>
 404
 405 <para>
 406 The latest version of SAMBA (version 3.0 as of this writing), now
 407 includes a functioning winbindd daemon.  Please refer to the
 408 <ulink url="http://samba.org/">main SAMBA web page</ulink> or,
 409 better yet, your closest SAMBA mirror site for instructions on
 410 downloading the source code.
 411 </para>
 412
 413 <para>
 414 To allow Domain users the ability to access SAMBA shares and
 415 files, as well as potentially other services provided by your
 416 SAMBA machine, PAM (pluggable authentication modules) must
 417 be setup properly on your machine.  In order to compile the
 418 winbind modules, you should have at least the pam libraries resident
 419 on your system.  For recent RedHat systems (7.1, for instance), that
 420 means <filename>pam-0.74-22</filename>.  For best results, it is helpful to also
 421 install the development packages in <filename>pam-devel-0.74-22</filename>.
 422 </para>
 423
 424 </sect2>
 425
 426
 427 <sect2>
 428 <title>Testing Things Out</title>
 429
 430 <para>
 431 Before starting, it is probably best to kill off all the SAMBA
 432 related daemons running on your server.  Kill off all <command>smbd</command>,
 433 <command>nmbd</command>, and <command>winbindd</command> processes that may
 434 be running.  To use PAM, you will want to make sure that you have the
 435 standard PAM package (for RedHat) which supplies the <filename>/etc/pam.d</filename>
 436 directory structure, including the pam modules are used by pam-aware
 437 services, several pam libraries, and the <filename>/usr/doc</filename>
 438 and <filename>/usr/man</filename> entries for pam.  Winbind built better
 439 in SAMBA if the pam-devel package was also installed.  This package includes
 440 the header files needed to compile pam-aware applications. For instance,
 441 my RedHat system has both <filename>pam-0.74-22</filename> and
 442 <filename>pam-devel-0.74-22</filename> RPMs installed.
 443 </para>
 444
 445 <sect3>
 446 <title>Configure and compile SAMBA</title>
 447
 448 <para>
 449 The configuration and compilation of SAMBA is pretty straightforward.
 450 The first three steps may not be necessary depending upon
 451 whether or not you have previously built the Samba binaries.
 452 </para>
 453
 454 <para><programlisting>
 455 <prompt>root#</prompt> <command>autoconf</command>
 456 <prompt>root#</prompt> <command>make clean</command>
 457 <prompt>root#</prompt> <command>rm config.cache</command>
 458 <prompt>root#</prompt> <command>./configure</command>
 459 <prompt>root#</prompt> <command>make</command>
 460 <prompt>root#</prompt> <command>make install</command>
 461 </programlisting></para>
 462
 463
 464 <para>
 465 This will, by default, install SAMBA in <filename>/usr/local/samba</filename>.
 466 See the main SAMBA documentation if you want to install SAMBA somewhere else.
 467 It will also build the winbindd executable and libraries.
 468 </para>
 469
 470 </sect3>
 471
 472 <sect3>
 473 <title>Configure <filename>nsswitch.conf</filename> and the
 474 winbind libraries</title>
 475
 476 <para>
 477 The libraries needed to run the <command>winbindd</command> daemon
 478 through nsswitch need to be copied to their proper locations, so
 479 </para>
 480
 481 <para>
 482 <prompt>root#</prompt> <command>cp ../samba/source/nsswitch/libnss_winbind.so /lib</command>
 483 </para>
 484
 485 <para>
 486 I also found it necessary to make the following symbolic link:
 487 </para>
 488
 489 <para>
 490 <prompt>root#</prompt> <command>ln -s /lib/libnss_winbind.so /lib/libnss_winbind.so.2</command>
 491 </para>
 492
 493 <para>And, in the case of Sun solaris:</para>
 494 <para>
 495 <prompt>root#</prompt> <command>ln -s /usr/lib/libnss_winbind.so /usr/lib/libnss_winbind.so.1</command>
 496 <prompt>root#</prompt> <command>ln -s /usr/lib/libnss_winbind.so /usr/lib/nss_winbind.so.1</command>
 497 <prompt>root#</prompt> <command>ln -s /usr/lib/libnss_winbind.so /usr/lib/nss_winbind.so.2</command>
 498 </para>
 499
 500 <para>
 501 Now, as root you need to edit <filename>/etc/nsswitch.conf</filename> to
 502 allow user and group entries to be visible from the <command>winbindd</command>
 503 daemon.  My <filename>/etc/nsswitch.conf</filename> file look like
 504 this after editing:
 505 </para>
 506
 507 <para><programlisting>
 508         passwd:     files winbind
 509         shadow:     files
 510         group:      files winbind
 511 </programlisting></para>
 512
 513 <para>
 514 The libraries needed by the winbind daemon will be automatically
 515 entered into the <command>ldconfig</command> cache the next time
 516 your system reboots, but it
 517 is faster (and you don't need to reboot) if you do it manually:
 518 </para>
 519
 520 <para>
 521 <prompt>root#</prompt> <command>/sbin/ldconfig -v | grep winbind</command>
 522 </para>
 523
 524 <para>
 525 This makes <filename>libnss_winbind</filename> available to winbindd
 526 and echos back a check to you.
 527 </para>
 528
 529 </sect3>
 530
 531
 532 <sect3>
 533 <title>Configure smb.conf</title>
 534
 535 <para>
 536 Several parameters are needed in the smb.conf file to control
 537 the behavior of <command>winbindd</command>. Configure
 538 <filename>smb.conf</filename> These are described in more detail in
 539 the <ulink url="winbindd.8.html">winbindd(8)</ulink> man page.  My
 540 <filename>smb.conf</filename> file was modified to
 541 include the following entries in the [global] section:
 542 </para>
 543
 544 <para><programlisting>
 545 [global]
 546      &lt;...&gt;
 547      # separate domain and username with '+', like DOMAIN+username
 548      <ulink url="winbindd.8.html#WINBINDSEPARATOR">winbind separator</ulink> = +
 549      # use uids from 10000 to 20000 for domain users
 550      <ulink url="winbindd.8.html#WINBINDUID">winbind uid</ulink> = 10000-20000
 551      # use gids from 10000 to 20000 for domain groups
 552      <ulink url="winbindd.8.html#WINBINDGID">winbind gid</ulink> = 10000-20000
 553      # allow enumeration of winbind users and groups
 554      <ulink url="winbindd.8.html#WINBINDENUMUSERS">winbind enum users</ulink> = yes
 555      <ulink url="winbindd.8.html#WINBINDENUMGROUP">winbind enum groups</ulink> = yes
 556      # give winbind users a real shell (only needed if they have telnet access)
 557      <ulink url="winbindd.8.html#TEMPLATEHOMEDIR">template homedir</ulink> = /home/winnt/%D/%U
 558      <ulink url="winbindd.8.html#TEMPLATESHELL">template shell</ulink> = /bin/bash
 559 </programlisting></para>
 560
 561 </sect3>
 562
 563
 564 <sect3>
 565 <title>Join the SAMBA server to the PDC domain</title>
 566
 567 <para>
 568 Enter the following command to make the SAMBA server join the
 569 PDC domain, where <replaceable>DOMAIN</replaceable> is the name of
 570 your Windows domain and <replaceable>Administrator</replaceable> is
 571 a domain user who has administrative privileges in the domain.
 572 </para>
 573
 574
 575 <para>
 576 <prompt>root#</prompt> <command>/usr/local/samba/bin/net join -S PDC -U Administrator</command>
 577 </para>
 578
 579
 580 <para>
 581 The proper response to the command should be: "Joined the domain
 582 <replaceable>DOMAIN</replaceable>" where <replaceable>DOMAIN</replaceable>
 583 is your DOMAIN name.
 584 </para>
 585
 586 </sect3>
 587
 588
 589 <sect3>
 590 <title>Start up the winbindd daemon and test it!</title>
 591
 592 <para>
 593 Eventually, you will want to modify your smb startup script to
 594 automatically invoke the winbindd daemon when the other parts of
 595 SAMBA start, but it is possible to test out just the winbind
 596 portion first.  To start up winbind services, enter the following
 597 command as root:
 598 </para>
 599
 600 <para>
 601 <prompt>root#</prompt> <command>/usr/local/samba/bin/winbindd</command>
 602 </para>
 603
 604 <para>
 605 Winbindd can now also run in 'dual daemon mode'. This will make it
 606 run as 2 processes. The first will answer all requests from the cache,
 607 thus making responses to clients faster. The other will
 608 update the cache for the query that the first has just responded.
 609 Advantage of this is that responses stay accurate and are faster.
 610 You can enable dual daemon mode by adding '-B' to the commandline:
 611 </para>
 612
 613 <para>
 614 <prompt>root#</prompt> <command>/usr/local/samba/bin/winbindd -B</command>
 615 </para>
 616
 617 <para>
 618 I'm always paranoid and like to make sure the daemon
 619 is really running...
 620 </para>
 621
 622 <para>
 623 <prompt>root#</prompt> <command>ps -ae | grep winbindd</command>
 624 </para>
 625 <para>
 626 This command should produce output like this, if the daemon is running
 627 </para>
 628 <para>
 629 3025 ?        00:00:00 winbindd
 630 </para>
 631
 632 <para>
 633 Now... for the real test, try to get some information about the
 634 users on your PDC
 635 </para>
 636
 637 <para>
 638 <prompt>root#</prompt> <command>/usr/local/samba/bin/wbinfo -u</command>
 639 </para>
 640
 641 <para>
 642 This should echo back a list of users on your Windows users on
 643 your PDC.  For example, I get the following response:
 644 </para>
 645
 646 <para><programlisting>
 647         CEO+Administrator
 648         CEO+burdell
 649         CEO+Guest
 650         CEO+jt-ad
 651         CEO+krbtgt
 652         CEO+TsInternetUser
 653 </programlisting></para>
 654
 655 <para>
 656 Obviously, I have named my domain 'CEO' and my <parameter>winbind
 657 separator</parameter> is '+'.
 658 </para>
 659
 660 <para>
 661 You can do the same sort of thing to get group information from
 662 the PDC:
 663 </para>
 664
 665 <para><programlisting>
 666 <prompt>root#</prompt> <command>/usr/local/samba/bin/wbinfo -g</command>
 667         CEO+Domain Admins
 668         CEO+Domain Users
 669         CEO+Domain Guests
 670         CEO+Domain Computers
 671         CEO+Domain Controllers
 672         CEO+Cert Publishers
 673         CEO+Schema Admins
 674         CEO+Enterprise Admins
 675         CEO+Group Policy Creator Owners
 676 </programlisting></para>
 677
 678 <para>
 679 The function 'getent' can now be used to get unified
 680 lists of both local and PDC users and groups.
 681 Try the following command:
 682 </para>
 683
 684 <para>
 685 <prompt>root#</prompt> <command>getent passwd</command>
 686 </para>
 687
 688 <para>
 689 You should get a list that looks like your <filename>/etc/passwd</filename>
 690 list followed by the domain users with their new uids, gids, home
 691 directories and default shells.
 692 </para>
 693
 694 <para>
 695 The same thing can be done for groups with the command
 696 </para>
 697
 698 <para>
 699 <prompt>root#</prompt> <command>getent group</command>
 700 </para>
 701
 702 </sect3>
 703
 704
 705 <sect3>
 706 <title>Fix the init.d startup scripts</title>
 707
 708 <sect4>
 709 <title>Linux</title>
 710
 711 <para>
 712 The <command>winbindd</command> daemon needs to start up after the
 713 <command>smbd</command> and <command>nmbd</command> daemons are running.
 714 To accomplish this task, you need to modify the startup scripts of your system.
 715 They are located at <filename>/etc/init.d/smb</filename> in RedHat and
 716 <filename>/etc/init.d/samba</filename> in Debian.
 717 script to add commands to invoke this daemon in the proper sequence.  My
 718 startup script starts up <command>smbd</command>,
 719 <command>nmbd</command>, and <command>winbindd</command> from the
 720 <filename>/usr/local/samba/bin</filename> directory directly.  The 'start'
 721 function in the script looks like this:
 722 </para>
 723
 724 <para><programlisting>
 725 start() {
 726         KIND="SMB"
 727         echo -n $"Starting $KIND services: "
 728         daemon /usr/local/samba/bin/smbd $SMBDOPTIONS
 729         RETVAL=$?
 730         echo
 731         KIND="NMB"
 732         echo -n $"Starting $KIND services: "
 733         daemon /usr/local/samba/bin/nmbd $NMBDOPTIONS
 734         RETVAL2=$?
 735         echo
 736         KIND="Winbind"
 737         echo -n $"Starting $KIND services: "
 738         daemon /usr/local/samba/bin/winbindd
 739         RETVAL3=$?
 740         echo
 741         [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] &amp;&amp; \
 742                 touch /var/lock/subsys/smb || RETVAL=1
 743         return $RETVAL
 744 }
 745 </programlisting></para>
 746
 747 <para>If you would like to run winbindd in dual daemon mode, replace
 748 the line
 749 <programlisting>
 750         daemon /usr/local/samba/bin/winbindd
 751 </programlisting>
 752
 753 in the example above with:
 754
 755 <programlisting>
 756         daemon /usr/local/samba/bin/winbindd -B
 757 </programlisting>.
 758 </para>
 759
 760 <para>
 761 The 'stop' function has a corresponding entry to shut down the
 762 services and looks like this:
 763 </para>
 764
 765 <para><programlisting>
 766 stop() {
 767         KIND="SMB"
 768         echo -n $"Shutting down $KIND services: "
 769         killproc smbd
 770         RETVAL=$?
 771         echo
 772         KIND="NMB"
 773         echo -n $"Shutting down $KIND services: "
 774         killproc nmbd
 775         RETVAL2=$?
 776         echo
 777         KIND="Winbind"
 778         echo -n $"Shutting down $KIND services: "
 779         killproc winbindd
 780         RETVAL3=$?
 781         [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] &amp;&amp; \
 782                  rm -f /var/lock/subsys/smb
 783         echo ""
 784         return $RETVAL
 785 }
 786 </programlisting></para>
 787 </sect4>
 788
 789 <sect4>
 790 <title>Solaris</title>
 791
 792 <para>Winbind doesn't work on solaris 9, see the <link linkend="winbind-solaris9">Portability</link> chapter for details.</para>
 793
 794 <para>On solaris, you need to modify the
 795 <filename>/etc/init.d/samba.server</filename> startup script. It usually
 796 only starts smbd and nmbd but should now start winbindd too. If you
 797 have samba installed in <filename>/usr/local/samba/bin</filename>,
 798 the file could contains something like this:
 799 </para>
 800
 801 <para><programlisting>
 802         ##
 803         ## samba.server
 804         ##
 805
 806         if [ ! -d /usr/bin ]
 807         then                    # /usr not mounted
 808                 exit
 809         fi
 810
 811         killproc() {            # kill the named process(es)
 812                 pid=`/usr/bin/ps -e |
 813                      /usr/bin/grep -w $1 |
 814                      /usr/bin/sed -e 's/^  *//' -e 's/ .*//'`
 815                 [ "$pid" != "" ] &amp;&amp; kill $pid
 816         }
 817
 818         # Start/stop processes required for samba server
 819
 820         case "$1" in
 821
 822         'start')
 823         #
 824         # Edit these lines to suit your installation (paths, workgroup, host)
 825         #
 826         echo Starting SMBD
 827            /usr/local/samba/bin/smbd -D -s \
 828                 /usr/local/samba/smb.conf
 829
 830         echo Starting NMBD
 831            /usr/local/samba/bin/nmbd -D -l \
 832                 /usr/local/samba/var/log -s /usr/local/samba/smb.conf
 833
 834         echo Starting Winbind Daemon
 835            /usr/local/samba/bin/winbindd
 836            ;;
 837
 838         'stop')
 839            killproc nmbd
 840            killproc smbd
 841            killproc winbindd
 842            ;;
 843
 844         *)
 845            echo "Usage: /etc/init.d/samba.server { start | stop }"
 846            ;;
 847         esac
 848 </programlisting></para>
 849
 850 <para>
 851 Again, if you would like to run samba in dual daemon mode, replace
 852 <programlisting>
 853         /usr/local/samba/bin/winbindd
 854 </programlisting>
 855
 856 in the script above with:
 857
 858 <programlisting>
 859         /usr/local/samba/bin/winbindd -B
 860 </programlisting>
 861 </para>
 862
 863 </sect4>
 864
 865 <sect4>
 866 <title>Restarting</title>
 867 <para>
 868 If you restart the <command>smbd</command>, <command>nmbd</command>,
 869 and <command>winbindd</command> daemons at this point, you
 870 should be able to connect to the samba server as a domain member just as
 871 if you were a local user.
 872 </para>
 873 </sect4>
 874 </sect3>
 875
 876 <sect3>
 877 <title>Configure Winbind and PAM</title>
 878
 879 <para>
 880 If you have made it this far, you know that winbindd and samba are working
 881 together.  If you want to use winbind to provide authentication for other
 882 services, keep reading.  The pam configuration files need to be altered in
 883 this step.  (Did you remember to make backups of your original
 884 <filename>/etc/pam.d</filename> files? If not, do it now.)
 885 </para>
 886
 887 <para>
 888 You will need a pam module to use winbindd with these other services.  This
 889 module will be compiled in the <filename>../source/nsswitch</filename> directory
 890 by invoking the command
 891 </para>
 892
 893 <para>
 894 <prompt>root#</prompt> <command>make nsswitch/pam_winbind.so</command>
 895 </para>
 896
 897 <para>
 898 from the <filename>../source</filename> directory.  The
 899 <filename>pam_winbind.so</filename> file should be copied to the location of
 900 your other pam security modules.  On my RedHat system, this was the
 901 <filename>/lib/security</filename> directory. On Solaris, the pam security
 902 modules reside in <filename>/usr/lib/security</filename>.
 903 </para>
 904
 905 <para>
 906 <prompt>root#</prompt> <command>cp ../samba/source/nsswitch/pam_winbind.so /lib/security</command>
 907 </para>
 908
 909 <sect4>
 910 <title>Linux/FreeBSD-specific PAM configuration</title>
 911
 912 <para>
 913 The <filename>/etc/pam.d/samba</filename> file does not need to be changed. I
 914 just left this fileas it was:
 915 </para>
 916
 917
 918 <para><programlisting>
 919         auth    required        /lib/security/pam_stack.so service=system-auth
 920         account required        /lib/security/pam_stack.so service=system-auth
 921 </programlisting></para>
 922
 923 <para>
 924 The other services that I modified to allow the use of winbind
 925 as an authentication service were the normal login on the console (or a terminal
 926 session), telnet logins, and ftp service.  In order to enable these
 927 services, you may first need to change the entries in
 928 <filename>/etc/xinetd.d</filename> (or <filename>/etc/inetd.conf</filename>).
 929 RedHat 7.1 uses the new xinetd.d structure, in this case you need
 930 to change the lines in <filename>/etc/xinetd.d/telnet</filename>
 931 and <filename>/etc/xinetd.d/wu-ftp</filename> from
 932 </para>
 933
 934 <para><programlisting>
 935         enable = no
 936 </programlisting></para>
 937
 938 <para>
 939 to
 940 </para>
 941
 942 <para><programlisting>
 943         enable = yes
 944 </programlisting></para>
 945
 946 <para>
 947 For ftp services to work properly, you will also need to either
 948 have individual directories for the domain users already present on
 949 the server, or change the home directory template to a general
 950 directory for all domain users.  These can be easily set using
 951 the <filename>smb.conf</filename> global entry
 952 <command>template homedir</command>.
 953 </para>
 954
 955 <para>
 956 The <filename>/etc/pam.d/ftp</filename> file can be changed
 957 to allow winbind ftp access in a manner similar to the
 958 samba file.  My <filename>/etc/pam.d/ftp</filename> file was
 959 changed to look like this:
 960 </para>
 961
 962 <para><programlisting>
 963         auth       required     /lib/security/pam_listfile.so item=user sense=deny \
 964                  file=/etc/ftpusers onerr=succeed
 965         auth       sufficient   /lib/security/pam_winbind.so
 966         auth       required     /lib/security/pam_stack.so service=system-auth
 967         auth       required     /lib/security/pam_shells.so
 968         account    sufficient   /lib/security/pam_winbind.so
 969         account    required     /lib/security/pam_stack.so service=system-auth
 970         session    required     /lib/security/pam_stack.so service=system-auth
 971 </programlisting></para>
 972
 973 <para>
 974 The <filename>/etc/pam.d/login</filename> file can be changed nearly the
 975 same way.  It now looks like this:
 976 </para>
 977
 978 <para><programlisting>
 979         auth       required     /lib/security/pam_securetty.so
 980         auth       sufficient   /lib/security/pam_winbind.so
 981         auth       sufficient   /lib/security/pam_unix.so use_first_pass
 982         auth       required     /lib/security/pam_stack.so service=system-auth
 983         auth       required     /lib/security/pam_nologin.so
 984         account    sufficient   /lib/security/pam_winbind.so
 985         account    required     /lib/security/pam_stack.so service=system-auth
 986         password   required     /lib/security/pam_stack.so service=system-auth
 987         session    required     /lib/security/pam_stack.so service=system-auth
 988         session    optional     /lib/security/pam_console.so
 989 </programlisting></para>
 990
 991 <para>
 992 In this case, I added the <command>auth sufficient /lib/security/pam_winbind.so</command>
 993 lines as before, but also added the <command>required pam_securetty.so</command>
 994 above it, to disallow root logins over the network.  I also added a
 995 <command>sufficient /lib/security/pam_unix.so use_first_pass</command>
 996 line after the <command>winbind.so</command> line to get rid of annoying
 997 double prompts for passwords.
 998 </para>
 999
1000 </sect4>
1001
1002 <sect4>
1003 <title>Solaris-specific configuration</title>
1004
1005 <para>
1006 The /etc/pam.conf needs to be changed. I changed this file so that my Domain
1007 users can logon both locally as well as telnet.The following are the changes
1008 that I made.You can customize the pam.conf file as per your requirements,but
1009 be sure of those changes because in the worst case it will leave your system
1010 nearly impossible to boot.
1011 </para>
1012
1013 <para><programlisting>
1014         #
1015         #ident  "@(#)pam.conf   1.14    99/09/16 SMI"
1016         #
1017         # Copyright (c) 1996-1999, Sun Microsystems, Inc.
1018         # All Rights Reserved.
1019         #
1020         # PAM configuration
1021         #
1022         # Authentication management
1023         #
1024         login   auth required   /usr/lib/security/pam_winbind.so
1025         login   auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
1026         login   auth required   /usr/lib/security/$ISA/pam_dial_auth.so.1 try_first_pass
1027         #
1028         rlogin  auth sufficient /usr/lib/security/pam_winbind.so
1029         rlogin  auth sufficient /usr/lib/security/$ISA/pam_rhosts_auth.so.1
1030         rlogin  auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
1031         #
1032         dtlogin auth sufficient /usr/lib/security/pam_winbind.so
1033         dtlogin auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
1034         #
1035         rsh     auth required   /usr/lib/security/$ISA/pam_rhosts_auth.so.1
1036         other   auth sufficient /usr/lib/security/pam_winbind.so
1037         other   auth required   /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass
1038         #
1039         # Account management
1040         #
1041         login   account sufficient      /usr/lib/security/pam_winbind.so
1042         login   account requisite       /usr/lib/security/$ISA/pam_roles.so.1
1043         login   account required        /usr/lib/security/$ISA/pam_unix.so.1
1044         #
1045         dtlogin account sufficient      /usr/lib/security/pam_winbind.so
1046         dtlogin account requisite       /usr/lib/security/$ISA/pam_roles.so.1
1047         dtlogin account required        /usr/lib/security/$ISA/pam_unix.so.1
1048         #
1049         other   account sufficient      /usr/lib/security/pam_winbind.so
1050         other   account requisite       /usr/lib/security/$ISA/pam_roles.so.1
1051         other   account required        /usr/lib/security/$ISA/pam_unix.so.1
1052         #
1053         # Session management
1054         #
1055         other   session required        /usr/lib/security/$ISA/pam_unix.so.1
1056         #
1057         # Password management
1058         #
1059         #other   password sufficient     /usr/lib/security/pam_winbind.so
1060         other   password required       /usr/lib/security/$ISA/pam_unix.so.1
1061         dtsession auth required /usr/lib/security/$ISA/pam_unix.so.1
1062         #
1063         # Support for Kerberos V5 authentication (uncomment to use Kerberos)
1064         #
1065         #rlogin auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1066         #login  auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1067         #dtlogin        auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1068         #other  auth optional   /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1069         #dtlogin        account optional /usr/lib/security/$ISA/pam_krb5.so.1
1070         #other  account optional /usr/lib/security/$ISA/pam_krb5.so.1
1071         #other  session optional /usr/lib/security/$ISA/pam_krb5.so.1
1072         #other  password optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass
1073 </programlisting></para>
1074
1075 <para>
1076 I also added a try_first_pass line after the winbind.so line to get rid of
1077 annoying double prompts for passwords.
1078 </para>
1079
1080 <para>
1081 Now restart your Samba and try connecting through your application that you
1082 configured in the pam.conf.
1083 </para>
1084
1085 </sect4>
1086
1087 </sect3>
1088
1089 </sect2>
1090
1091 </sect1>
1092
1093 <sect1>
1094         <title>Limitations</title>
1095
1096         <para>Winbind has a number of limitations in its current
1097         released version that we hope to overcome in future
1098         releases:</para>
1099
1100         <itemizedlist>
1101                 <listitem><para>Winbind is currently only available for
1102                 the Linux, Solaris and IRIX operating systems, although ports to other operating
1103                 systems are certainly possible. For such ports to be feasible,
1104                 we require the C library of the target operating system to
1105                 support the Name Service Switch and Pluggable Authentication
1106                 Modules systems. This is becoming more common as NSS and
1107                 PAM gain        support among UNIX vendors.</para></listitem>
1108
1109                 <listitem><para>The mappings of Windows NT RIDs to UNIX ids
1110                 is not made algorithmically and depends on the order in which
1111                 unmapped users or groups are seen by winbind. It may be difficult
1112                 to recover the mappings of rid to UNIX id mapping if the file
1113                 containing this information is corrupted or destroyed.</para>
1114                 </listitem>
1115
1116                 <listitem><para>Currently the winbind PAM module does not take
1117                 into account possible workstation and logon time restrictions
1118                 that may be been set for Windows NT users, this is
1119                 instead up to the PDC to enforce.</para></listitem>
1120         </itemizedlist>
1121 </sect1>
1122
1123
1124 <sect1>
1125         <title>Conclusion</title>
1126
1127         <para>The winbind system, through the use of the Name Service
1128         Switch, Pluggable Authentication Modules, and appropriate
1129         Microsoft RPC calls have allowed us to provide seamless
1130         integration of Microsoft Windows NT domain users on a
1131         UNIX system. The result is a great reduction in the administrative
1132         cost of running a mixed UNIX and NT network.</para>
1133
1134 </sect1>
1135
1136 </chapter>