1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
|
<chapter id="passdb">
<chapterinfo>
<author>
<firstname>Jelmer</firstname><surname>Vernooij</surname>
<affiliation>
<orgname>The Samba Team</orgname>
<address><email>jelmer@samba.org</email></address>
</affiliation>
</author>
<author>
<firstname>Gerald (Jerry)</firstname><surname>Carter</surname>
<affiliation>
<orgname>Samba Team</orgname>
<address><email>jerry@samba.org</email></address>
</affiliation>
</author>
<author>
<firstname>Olivier (lem)</firstname><surname>Lemaire</surname>
<affiliation>
<orgname>IDEALX</orgname>
<address><email>olem@IDEALX.org</email></address>
</affiliation>
</author>
<author>
<firstname>Jeremy</firstname><surname>Allison</surname>
<affiliation>
<orgname>Samba Team</orgname>
<address>
<email>jra@samba.org</email>
</address>
</affiliation>
</author>
<pubdate>February 2003</pubdate>
</chapterinfo>
<title>User information database</title>
<sect1>
<title>Introduction</title>
<para>Old windows clients send plain text passwords over the wire.
Samba can check these passwords by crypting them and comparing them
to the hash stored in the unix user database.
</para>
<para>
Newer windows clients send encrypted passwords (so-called
Lanman and NT hashes) over
the wire, instead of plain text passwords. The newest clients
will only send encrypted passwords and refuse to send plain text
passwords, unless their registry is tweaked.
</para>
<para>These passwords can't be converted to unix style encrypted
passwords. Because of that you can't use the standard unix
user database, and you have to store the Lanman and NT hashes
somewhere else. </para>
<para>Next to a differently encrypted passwords,
windows also stores certain data for each user
that is not stored in a unix user database, e.g.
workstations the user may logon from, the location where his/her
profile is stored, etc.
Samba retrieves and stores this information using a "passdb backend".
Commonly
available backends are LDAP, plain text file, MySQL and nisplus.
For more information, see the documentation about the
<command>passdb backend = </command> parameter.
</para>
</sect1>
<sect1>
<title>Important Notes About Security</title>
<para>The unix and SMB password encryption techniques seem similar
on the surface. This similarity is, however, only skin deep. The unix
scheme typically sends clear text passwords over the network when
logging in. This is bad. The SMB encryption scheme never sends the
cleartext password over the network but it does store the 16 byte
hashed values on disk. This is also bad. Why? Because the 16 byte hashed
values are a "password equivalent". You cannot derive the user's
password from them, but they could potentially be used in a modified
client to gain access to a server. This would require considerable
technical knowledge on behalf of the attacker but is perfectly possible.
You should thus treat the data stored in whatever
passdb backend you use (smbpasswd file, ldap, mysql) as though it contained the
cleartext passwords of all your users. Its contents must be kept
secret, and the file should be protected accordingly.</para>
<para>Ideally we would like a password scheme which neither requires
plain text passwords on the net or on disk. Unfortunately this
is not available as Samba is stuck with being compatible with
other SMB systems (WinNT, WfWg, Win95 etc). </para>
<warning>
<para>Note that Windows NT 4.0 Service pack 3 changed the
default for permissible authentication so that plaintext
passwords are <emphasis>never</emphasis> sent over the wire.
The solution to this is either to switch to encrypted passwords
with Samba or edit the Windows NT registry to re-enable plaintext
passwords. See the document WinNT.txt for details on how to do
this.</para>
<para>Other Microsoft operating systems which also exhibit
this behavior includes</para>
<simplelist>
<member>MS DOS Network client 3.0 with
the basic network redirector installed</member>
<member>Windows 95 with the network redirector
update installed</member>
<member>Windows 98 [se]</member>
<member>Windows 2000</member>
</simplelist>
<para><emphasis>Note :</emphasis>All current release of
Microsoft SMB/CIFS clients support authentication via the
SMB Challenge/Response mechanism described here. Enabling
clear text authentication does not disable the ability
of the client to participate in encrypted authentication.</para>
</warning>
<sect2>
<title>Advantages of SMB Encryption</title>
<simplelist>
<member>plain text passwords are not passed across
the network. Someone using a network sniffer cannot just
record passwords going to the SMB server.</member>
<member>WinNT doesn't like talking to a server
that isn't using SMB encrypted passwords. It will refuse
to browse the server if the server is also in user level
security mode. It will insist on prompting the user for the
password on each connection, which is very annoying. The
only things you can do to stop this is to use SMB encryption.
</member>
</simplelist>
</sect2>
<sect2>
<title>Advantages of non-encrypted passwords</title>
<simplelist>
<member>plain text passwords are not kept
on disk. </member>
<member>uses same password file as other unix
services such as login and ftp</member>
<member>you are probably already using other
services (such as telnet and ftp) which send plain text
passwords over the net, so sending them for SMB isn't
such a big deal.</member>
</simplelist>
</sect2>
</sect1>
<sect1>
<title>The smbpasswd Command</title>
<para>The smbpasswd utility is a utility similar to the
<command>passwd</command> or <command>yppasswd</command> programs.
It maintains the two 32 byte password fields
in the passdb backend. </para>
<para><command>smbpasswd</command> works in a client-server mode
where it contacts the local smbd to change the user's password on its
behalf. This has enormous benefits - as follows.</para>
<para><command>smbpasswd</command> has the capability
to change passwords on Windows NT servers (this only works when
the request is sent to the NT Primary Domain Controller if you
are changing an NT Domain user's password).</para>
<para>To run smbpasswd as a normal user just type :</para>
<para><prompt>$ </prompt><userinput>smbpasswd</userinput></para>
<para><prompt>Old SMB password: </prompt><userinput><type old value here -
or hit return if there was no old password></userinput></para>
<para><prompt>New SMB Password: </prompt><userinput><type new value>
</userinput></para>
<para><prompt>Repeat New SMB Password: </prompt><userinput><re-type new value
</userinput></para>
<para>If the old value does not match the current value stored for
that user, or the two new values do not match each other, then the
password will not be changed.</para>
<para>If invoked by an ordinary user it will only allow the user
to change his or her own Samba password.</para>
<para>If run by the root user smbpasswd may take an optional
argument, specifying the user name whose SMB password you wish to
change. Note that when run as root smbpasswd does not prompt for
or check the old password value, thus allowing root to set passwords
for users who have forgotten their passwords.</para>
<para><command>smbpasswd</command> is designed to work in the same way
and be familiar to UNIX users who use the <command>passwd</command> or
<command>yppasswd</command> commands.</para>
<para>For more details on using <command>smbpasswd</command> refer
to the man page which will always be the definitive reference.</para>
</sect1>
<!--
<sect1>
<title>The <command>pdbedit</command> command</title>
FIXME
</sect1>
-->
<sect1>
<title>Plain text</title>
<para>
Older versions of samba retrieved user information from the unix user database
and eventually some other fields from the file <filename>/etc/samba/smbpasswd</filename>
or <filename>/etc/smbpasswd</filename>. When password encryption is disabled, no
data is stored at all.
</para>
</sect1>
<sect1>
<title>TDB</title>
<para>Samba can also store the user data in a "TDB" (Trivial Database). Using this backend
doesn't require any additional configuration. This backend is recommended for new installations who
don't require LDAP.
</para>
</sect1>
<sect1>
<title>LDAP</title>
<sect2>
<title>Introduction</title>
<para>
This document describes how to use an LDAP directory for storing Samba user
account information traditionally stored in the smbpasswd(5) file. It is
assumed that the reader already has a basic understanding of LDAP concepts
and has a working directory server already installed. For more information
on LDAP architectures and Directories, please refer to the following sites.
</para>
<itemizedlist>
<listitem><para>OpenLDAP - <ulink url="http://www.openldap.org/">http://www.openldap.org/</ulink></para></listitem>
<listitem><para>iPlanet Directory Server - <ulink url="http://iplanet.netscape.com/directory">http://iplanet.netscape.com/directory</ulink></para></listitem>
</itemizedlist>
<para>
Note that <ulink url="http://www.ora.com/">O'Reilly Publishing</ulink> is working on
a guide to LDAP for System Administrators which has a planned release date of
early summer, 2002.
</para>
<para>
Two additional Samba resources which may prove to be helpful are
</para>
<itemizedlist>
<listitem><para>The <ulink url="http://www.unav.es/cti/ldap-smb/ldap-smb-3-howto.html">Samba-PDC-LDAP-HOWTO</ulink>
maintained by Ignacio Coupeau.</para></listitem>
<listitem><para>The NT migration scripts from <ulink url="http://samba.idealx.org/">IDEALX</ulink> that are
geared to manage users and group in such a Samba-LDAP Domain Controller configuration.
</para></listitem>
</itemizedlist>
</sect2>
<sect2>
<title>Introduction</title>
<para>
Traditionally, when configuring <ulink url="smb.conf.5.html#ENCRYPTPASSWORDS">"encrypt
passwords = yes"</ulink> in Samba's <filename>smb.conf</filename> file, user account
information such as username, LM/NT password hashes, password change times, and account
flags have been stored in the <filename>smbpasswd(5)</filename> file. There are several
disadvantages to this approach for sites with very large numbers of users (counted
in the thousands).
</para>
<itemizedlist>
<listitem><para>
The first is that all lookups must be performed sequentially. Given that
there are approximately two lookups per domain logon (one for a normal
session connection such as when mapping a network drive or printer), this
is a performance bottleneck for lareg sites. What is needed is an indexed approach
such as is used in databases.
</para></listitem>
<listitem><para>
The second problem is that administrators who desired to replicate a
smbpasswd file to more than one Samba server were left to use external
tools such as <command>rsync(1)</command> and <command>ssh(1)</command>
and wrote custom, in-house scripts.
</para></listitem>
<listitem><para>
And finally, the amount of information which is stored in an
smbpasswd entry leaves no room for additional attributes such as
a home directory, password expiration time, or even a Relative
Identified (RID).
</para></listitem>
</itemizedlist>
<para>
As a result of these defeciencies, a more robust means of storing user attributes
used by smbd was developed. The API which defines access to user accounts
is commonly referred to as the samdb interface (previously this was called the passdb
API, and is still so named in the CVS trees). In Samba 2.2.3, enabling support
for a samdb backend (e.g. <parameter>--with-ldapsam</parameter> or
<parameter>--with-tdbsam</parameter>) requires compile time support.
</para>
<para>
When compiling Samba to include the <parameter>--with-ldapsam</parameter> autoconf
option, smbd (and associated tools) will store and lookup user accounts in
an LDAP directory. In reality, this is very easy to understand. If you are
comfortable with using an smbpasswd file, simply replace "smbpasswd" with
"LDAP directory" in all the documentation.
</para>
<para>
There are a few points to stress about what the <parameter>--with-ldapsam</parameter>
does not provide. The LDAP support referred to in the this documentation does not
include:
</para>
<itemizedlist>
<listitem><para>A means of retrieving user account information from
an Windows 2000 Active Directory server.</para></listitem>
<listitem><para>A means of replacing /etc/passwd.</para></listitem>
</itemizedlist>
<para>
The second item can be accomplished by using LDAP NSS and PAM modules. LGPL
versions of these libraries can be obtained from PADL Software
(<ulink url="http://www.padl.com/">http://www.padl.com/</ulink>). However,
the details of configuring these packages are beyond the scope of this document.
</para>
</sect2>
<sect2>
<title>Supported LDAP Servers</title>
<para>
The LDAP samdb code in 2.2.3 has been developed and tested using the OpenLDAP
2.0 server and client libraries. The same code should be able to work with
Netscape's Directory Server and client SDK. However, due to lack of testing
so far, there are bound to be compile errors and bugs. These should not be
hard to fix. If you are so inclined, please be sure to forward all patches to
<ulink url="samba-patches@samba.org">samba-patches@samba.org</ulink> and
<ulink url="jerry@samba.org">jerry@samba.org</ulink>.
</para>
</sect2>
<sect2>
<title>Schema and Relationship to the RFC 2307 posixAccount</title>
<para>
Samba 3.0 includes the necessary schema file for OpenLDAP 2.0 in
<filename>examples/LDAP/samba.schema</filename>. The sambaAccount objectclass is given here:
</para>
<para><programlisting>
objectclass ( 1.3.1.5.1.4.1.7165.2.2.2 NAME 'sambaAccount' SUP top STRUCTURAL
DESC 'Samba Account'
MUST ( uid $ rid )
MAY ( cn $ lmPassword $ ntPassword $ pwdLastSet $ logonTime $
logoffTime $ kickoffTime $ pwdCanChange $ pwdMustChange $ acctFlags $
displayName $ smbHome $ homeDrive $ scriptPath $ profilePath $
description $ userWorkstations $ primaryGroupID $ domain ))
</programlisting></para>
<para>
The samba.schema file has been formatted for OpenLDAP 2.0. The OID's are
owned by the Samba Team and as such is legal to be openly published.
If you translate the schema to be used with Netscape DS, please
submit the modified schema file as a patch to <ulink
url="jerry@samba.org">jerry@samba.org</ulink>
</para>
<para>
Just as the smbpasswd file is mean to store information which supplements a
user's <filename>/etc/passwd</filename> entry, so is the sambaAccount object
meant to supplement the UNIX user account information. A sambaAccount is a
<constant>STRUCTURAL</constant> objectclass so it can be stored individually
in the directory. However, there are several fields (e.g. uid) which overlap
with the posixAccount objectclass outlined in RFC2307. This is by design.
</para>
<!--olem: we should perhaps have a note about shadowAccounts too as many
systems use them, isn'it ? -->
<para>
In order to store all user account information (UNIX and Samba) in the directory,
it is necessary to use the sambaAccount and posixAccount objectclasses in
combination. However, smbd will still obtain the user's UNIX account
information via the standard C library calls (e.g. getpwnam(), et. al.).
This means that the Samba server must also have the LDAP NSS library installed
and functioning correctly. This division of information makes it possible to
store all Samba account information in LDAP, but still maintain UNIX account
information in NIS while the network is transitioning to a full LDAP infrastructure.
</para>
</sect2>
<sect2>
<title>Configuring Samba with LDAP</title>
<sect3>
<title>OpenLDAP configuration</title>
<para>
To include support for the sambaAccount object in an OpenLDAP directory
server, first copy the samba.schema file to slapd's configuration directory.
</para>
<para>
<prompt>root# </prompt><command>cp samba.schema /etc/openldap/schema/</command>
</para>
<para>
Next, include the <filename>samba.schema</filename> file in <filename>slapd.conf</filename>.
The sambaAccount object contains two attributes which depend upon other schema
files. The 'uid' attribute is defined in <filename>cosine.schema</filename> and
the 'displayName' attribute is defined in the <filename>inetorgperson.schema</filename>
file. Both of these must be included before the <filename>samba.schema</filename> file.
</para>
<para><programlisting>
## /etc/openldap/slapd.conf
## schema files (core.schema is required by default)
include /etc/openldap/schema/core.schema
## needed for sambaAccount
include /etc/openldap/schema/cosine.schema
include /etc/openldap/schema/inetorgperson.schema
include /etc/openldap/schema/samba.schema
## uncomment this line if you want to support the RFC2307 (NIS) schema
## include /etc/openldap/schema/nis.schema
....
</programlisting></para>
<para>
It is recommended that you maintain some indices on some of the most usefull attributes,
like in the following example, to speed up searches made on sambaAccount objectclasses
(and possibly posixAccount and posixGroup as well).
</para>
<para><programlisting>
# Indices to maintain
## required by OpenLDAP 2.0
index objectclass eq
## support pb_getsampwnam()
index uid pres,eq
## support pdb_getsambapwrid()
index rid eq
## uncomment these if you are storing posixAccount and
## posixGroup entries in the directory as well
##index uidNumber eq
##index gidNumber eq
##index cn eq
##index memberUid eq
</programlisting></para>
</sect3>
<sect3>
<title>Configuring Samba</title>
<!--lem: <title>smb.conf LDAP parameters</title> -->
<para>
The following parameters are available in smb.conf only with <parameter>--with-ldapsam</parameter>
was included with compiling Samba.
</para>
<itemizedlist>
<listitem><para><ulink url="smb.conf.5.html#LDAPSSL">ldap ssl</ulink></para></listitem>
<listitem><para><ulink url="smb.conf.5.html#LDAPSERVER">ldap server</ulink></para></listitem>
<listitem><para><ulink url="smb.conf.5.html#LDAPADMINDN">ldap admin dn</ulink></para></listitem>
<listitem><para><ulink url="smb.conf.5.html#LDAPSUFFIX">ldap suffix</ulink></para></listitem>
<listitem><para><ulink url="smb.conf.5.html#LDAPFILTER">ldap filter</ulink></para></listitem>
<listitem><para><ulink url="smb.conf.5.html#LDAPPORT">ldap port</ulink></para></listitem>
</itemizedlist>
<para>
These are described in the <ulink url="smb.conf.5.html">smb.conf(5)</ulink> man
page and so will not be repeated here. However, a sample smb.conf file for
use with an LDAP directory could appear as
</para>
<para><programlisting>
## /usr/local/samba/lib/smb.conf
[global]
security = user
encrypt passwords = yes
netbios name = TASHTEGO
workgroup = NARNIA
# ldap related parameters
# define the DN to use when binding to the directory servers
# The password for this DN is not stored in smb.conf. Rather it
# must be set by using 'smbpasswd -w <replaceable>secretpw</replaceable>' to store the
# passphrase in the secrets.tdb file. If the "ldap admin dn" values
# changes, this password will need to be reset.
ldap admin dn = "cn=Samba Manager,ou=people,dc=samba,dc=org"
# specify the LDAP server's hostname (defaults to locahost)
ldap server = ahab.samba.org
# Define the SSL option when connecting to the directory
# ('off', 'start tls', or 'on' (default))
ldap ssl = start tls
# define the port to use in the LDAP session (defaults to 636 when
# "ldap ssl = on")
ldap port = 389
# specify the base DN to use when searching the directory
ldap suffix = "ou=people,dc=samba,dc=org"
# generally the default ldap search filter is ok
# ldap filter = "(&(uid=%u)(objectclass=sambaAccount))"
</programlisting></para>
</sect3>
</sect2>
<sect2>
<title>Accounts and Groups management</title>
<para>
As users accounts are managed thru the sambaAccount objectclass, you should
modify you existing administration tools to deal with sambaAccount attributes.
</para>
<para>
Machines accounts are managed with the sambaAccount objectclass, just
like users accounts. However, it's up to you to stored thoses accounts
in a different tree of you LDAP namespace: you should use
"ou=Groups,dc=plainjoe,dc=org" to store groups and
"ou=People,dc=plainjoe,dc=org" to store users. Just configure your
NSS and PAM accordingly (usually, in the /etc/ldap.conf configuration
file).
</para>
<para>
In Samba release 3.0, the group management system is based on posix
groups. This means that Samba make usage of the posixGroup objectclass.
For now, there is no NT-like group system management (global and local
groups).
</para>
</sect2>
<sect2>
<title>Security and sambaAccount</title>
<para>
There are two important points to remember when discussing the security
of sambaAccount entries in the directory.
</para>
<itemizedlist>
<listitem><para><emphasis>Never</emphasis> retrieve the lmPassword or
ntPassword attribute values over an unencrypted LDAP session.</para></listitem>
<listitem><para><emphasis>Never</emphasis> allow non-admin users to
view the lmPassword or ntPassword attribute values.</para></listitem>
</itemizedlist>
<para>
These password hashes are clear text equivalents and can be used to impersonate
the user without deriving the original clear text strings. For more information
on the details of LM/NT password hashes, refer to the <ulink
url="ENCRYPTION.html">ENCRYPTION chapter</ulink> of the Samba-HOWTO-Collection.
</para>
<para>
To remedy the first security issue, the "ldap ssl" smb.conf parameter defaults
to require an encrypted session (<command>ldap ssl = on</command>) using
the default port of 636
when contacting the directory server. When using an OpenLDAP 2.0 server, it
is possible to use the use the StartTLS LDAP extended operation in the place of
LDAPS. In either case, you are strongly discouraged to disable this security
(<command>ldap ssl = off</command>).
</para>
<para>
Note that the LDAPS protocol is deprecated in favor of the LDAPv3 StartTLS
extended operation. However, the OpenLDAP library still provides support for
the older method of securing communication between clients and servers.
</para>
<para>
The second security precaution is to prevent non-administrative users from
harvesting password hashes from the directory. This can be done using the
following ACL in <filename>slapd.conf</filename>:
</para>
<para><programlisting>
## allow the "ldap admin dn" access, but deny everyone else
access to attrs=lmPassword,ntPassword
by dn="cn=Samba Admin,ou=people,dc=plainjoe,dc=org" write
by * none
</programlisting></para>
</sect2>
<sect2>
<title>LDAP specials attributes for sambaAccounts</title>
<para>
The sambaAccount objectclass is composed of the following attributes:
</para>
<itemizedlist>
<listitem><para><constant>lmPassword</constant>: the LANMAN password 16-byte hash stored as a character
representation of a hexidecimal string.</para></listitem>
<listitem><para><constant>ntPassword</constant>: the NT password hash 16-byte stored as a character
representation of a hexidecimal string.</para></listitem>
<listitem><para><constant>pwdLastSet</constant>: The integer time in seconds since 1970 when the
<constant>lmPassword</constant> and <constant>ntPassword</constant> attributes were last set.
</para></listitem>
<listitem><para><constant>acctFlags</constant>: string of 11 characters surrounded by square brackets []
representing account flags such as U (user), W(workstation), X(no password expiration), and
D(disabled).</para></listitem>
<listitem><para><constant>logonTime</constant>: Integer value currently unused</para></listitem>
<listitem><para><constant>logoffTime</constant>: Integer value currently unused</para></listitem>
<listitem><para><constant>kickoffTime</constant>: Integer value currently unused</para></listitem>
<listitem><para><constant>pwdCanChange</constant>: Integer value currently unused</para></listitem>
<listitem><para><constant>pwdMustChange</constant>: Integer value currently unused</para></listitem>
<listitem><para><constant>homeDrive</constant>: specifies the drive letter to which to map the
UNC path specified by homeDirectory. The drive letter must be specified in the form "X:"
where X is the letter of the drive to map. Refer to the "logon drive" parameter in the
smb.conf(5) man page for more information.</para></listitem>
<listitem><para><constant>scriptPath</constant>: The scriptPath property specifies the path of
the user's logon script, .CMD, .EXE, or .BAT file. The string can be null. The path
is relative to the netlogon share. Refer to the "logon script" parameter in the
smb.conf(5) man page for more information.</para></listitem>
<listitem><para><constant>profilePath</constant>: specifies a path to the user's profile.
This value can be a null string, a local absolute path, or a UNC path. Refer to the
"logon path" parameter in the smb.conf(5) man page for more information.</para></listitem>
<listitem><para><constant>smbHome</constant>: The homeDirectory property specifies the path of
the home directory for the user. The string can be null. If homeDrive is set and specifies
a drive letter, homeDirectory should be a UNC path. The path must be a network
UNC path of the form \\server\share\directory. This value can be a null string.
Refer to the "logon home" parameter in the smb.conf(5) man page for more information.
</para></listitem>
<listitem><para><constant>userWorkstation</constant>: character string value currently unused.
</para></listitem>
<listitem><para><constant>rid</constant>: the integer representation of the user's relative identifier
(RID).</para></listitem>
<listitem><para><constant>primaryGroupID</constant>: the relative identifier (RID) of the primary group
of the user.</para></listitem>
</itemizedlist>
<para>
The majority of these parameters are only used when Samba is acting as a PDC of
a domain (refer to the <ulink url="Samba-PDC-HOWTO.html">Samba-PDC-HOWTO</ulink> for details on
how to configure Samba as a Primary Domain Controller). The following four attributes
are only stored with the sambaAccount entry if the values are non-default values:
</para>
<itemizedlist>
<listitem><para>smbHome</para></listitem>
<listitem><para>scriptPath</para></listitem>
<listitem><para>logonPath</para></listitem>
<listitem><para>homeDrive</para></listitem>
</itemizedlist>
<para>
These attributes are only stored with the sambaAccount entry if
the values are non-default values. For example, assume TASHTEGO has now been
configured as a PDC and that <command>logon home = \\%L\%u</command> was defined in
its <filename>smb.conf</filename> file. When a user named "becky" logons to the domain,
the <parameter>logon home</parameter> string is expanded to \\TASHTEGO\becky.
If the smbHome attribute exists in the entry "uid=becky,ou=people,dc=samba,dc=org",
this value is used. However, if this attribute does not exist, then the value
of the <parameter>logon home</parameter> parameter is used in its place. Samba
will only write the attribute value to the directory entry is the value is
something other than the default (e.g. \\MOBY\becky).
</para>
</sect2>
<sect2>
<title>Example LDIF Entries for a sambaAccount</title>
<para>
The following is a working LDIF with the inclusion of the posixAccount objectclass:
</para>
<para><programlisting>
dn: uid=guest2, ou=people,dc=plainjoe,dc=org
ntPassword: 878D8014606CDA29677A44EFA1353FC7
pwdMustChange: 2147483647
primaryGroupID: 1201
lmPassword: 552902031BEDE9EFAAD3B435B51404EE
pwdLastSet: 1010179124
logonTime: 0
objectClass: sambaAccount
uid: guest2
kickoffTime: 2147483647
acctFlags: [UX ]
logoffTime: 2147483647
rid: 19006
pwdCanChange: 0
</programlisting></para>
<para>
The following is an LDIF entry for using both the sambaAccount and
posixAccount objectclasses:
</para>
<para><programlisting>
dn: uid=gcarter, ou=people,dc=plainjoe,dc=org
logonTime: 0
displayName: Gerald Carter
lmPassword: 552902031BEDE9EFAAD3B435B51404EE
primaryGroupID: 1201
objectClass: posixAccount
objectClass: sambaAccount
acctFlags: [UX ]
userPassword: {crypt}BpM2ej8Rkzogo
uid: gcarter
uidNumber: 9000
cn: Gerald Carter
loginShell: /bin/bash
logoffTime: 2147483647
gidNumber: 100
kickoffTime: 2147483647
pwdLastSet: 1010179230
rid: 19000
homeDirectory: /home/tashtego/gcarter
pwdCanChange: 0
pwdMustChange: 2147483647
ntPassword: 878D8014606CDA29677A44EFA1353FC7
</programlisting></para>
</sect2>
</sect1>
<sect1>
<title>MySQL</title>
<sect2>
<title>Building</title>
<para>To build the plugin, run <command>make bin/pdb_mysql.so</command>
in the <filename>source/</filename> directory of samba distribution.
</para>
<para>Next, copy pdb_mysql.so to any location you want. I
strongly recommend installing it in $PREFIX/lib or /usr/lib/samba/</para>
</sect2>
<sect2>
<title>Creating the database</title>
<para>
You either can set up your own table and specify the field names to pdb_mysql (see below
for the column names) or use the default table. The file <filename>examples/pdb/mysql/mysql.dump</filename>
contains the correct queries to create the required tables. Use the command :
<command>mysql -u<replaceable>username</replaceable> -h<replaceable>hostname</replaceable> -p<replaceable>password</replaceable> <replaceable>databasename</replaceable> < <filename>/path/to/samba/examples/pdb/mysql/mysql.dump</filename></command>
</para>
</sect2>
<sect2>
<title>Configuring</title>
<para>This plugin lacks some good documentation, but here is some short info:</para>
<para>Add a the following to the <command>passdb backend</command> variable in your <filename>smb.conf</filename>:
<programlisting>
passdb backend = [other-plugins] plugin:/location/to/pdb_mysql.so:identifier [other-plugins]
</programlisting>
</para>
<para>The identifier can be any string you like, as long as it doesn't collide with
the identifiers of other plugins or other instances of pdb_mysql. If you
specify multiple pdb_mysql.so entries in 'passdb backend', you also need to
use different identifiers!
</para>
<para>
Additional options can be given thru the smb.conf file in the [global] section.
</para>
<para><programlisting>
identifier:mysql host - host name, defaults to 'localhost'
identifier:mysql password
identifier:mysql user - defaults to 'samba'
identifier:mysql database - defaults to 'samba'
identifier:mysql port - defaults to 3306
identifier:table - Name of the table containing users
</programlisting></para>
<para>
<emphasis>
WARNING: since the password for the mysql user is stored in the
smb.conf file, you should make the the smb.conf file
readable only to the user that runs samba. This is considered a security
bug and will be fixed soon.</emphasis>
</para>
<para>Names of the columns in this table(I've added column types those columns should have first):</para>
<para><programlisting>
identifier:logon time column - int(9)
identifier:logoff time column - int(9)
identifier:kickoff time column - int(9)
identifier:pass last set time column - int(9)
identifier:pass can change time column - int(9)
identifier:pass must change time column - int(9)
identifier:username column - varchar(255) - unix username
identifier:domain column - varchar(255) - NT domain user is part of
identifier:nt username column - varchar(255) - NT username
identifier:fullname column - varchar(255) - Full name of user
identifier:home dir column - varchar(255) - Unix homedir path
identifier:dir drive column - varchar(2) - Directory drive path (eg: 'H:')
identifier:logon script column - varchar(255) - Batch file to run on client side when logging on
identifier:profile path column - varchar(255) - Path of profile
identifier:acct desc column - varchar(255) - Some ASCII NT user data
identifier:workstations column - varchar(255) - Workstations user can logon to (or NULL for all)
identifier:unknown string column - varchar(255) - unknown string
identifier:munged dial column - varchar(255) - ?
identifier:uid column - int(9) - Unix user ID (uid)
identifier:gid column - int(9) - Unix user group (gid)
identifier:user sid column - varchar(255) - NT user SID
identifier:group sid column - varchar(255) - NT group ID
identifier:lanman pass column - varchar(255) - encrypted lanman password
identifier:nt pass column - varchar(255) - encrypted nt passwd
identifier:plain pass column - varchar(255) - plaintext password
identifier:acct control column - int(9) - nt user data
identifier:unknown 3 column - int(9) - unknown
identifier:logon divs column - int(9) - ?
identifier:hours len column - int(9) - ?
identifier:unknown 5 column - int(9) - unknown
identifier:unknown 6 column - int(9) - unknown
</programlisting></para>
<para>
Eventually, you can put a colon (:) after the name of each column, which
should specify the column to update when updating the table. You can also
specify nothing behind the colon - then the data from the field will not be
updated.
</para>
</sect2>
<sect2>
<title>Using plaintext passwords or encrypted password</title>
<para>
I strongly discourage the use of plaintext passwords, however, you can use them:
</para>
<para>
If you would like to use plaintext passwords, set 'identifier:lanman pass column' and 'identifier:nt pass column' to 'NULL' (without the quotes) and 'identifier:plain pass column' to the name of the column containing the plaintext passwords.
</para>
<para>
If you use encrypted passwords, set the 'identifier:plain pass column' to 'NULL' (without the quotes). This is the default.
</para>
</sect2>
<sect2>
<title>Getting non-column data from the table</title>
<para>
It is possible to have not all data in the database and making some 'constant'.
</para>
<para>
For example, you can set 'identifier:fullname column' to :
<command>CONCAT(First_name,' ',Sur_name)</command>
</para>
<para>
Or, set 'identifier:workstations column' to :
<command>NULL</command></para>
<para>See the MySQL documentation for more language constructs.</para>
</sect2>
</sect1>
<sect1>
<title>Passdb XML plugin</title>
<sect2>
<title>Building</title>
<para>This module requires libxml2 to be installed.</para>
<para>To build pdb_xml, run: <command>make bin/pdb_xml.so</command> in
the directory <filename>source/</filename>. </para>
</sect2>
<sect2>
<title>Usage</title>
<para>The usage of pdb_xml is pretty straightforward. To export data, use:
<command>pdbedit -e plugin:/usr/lib/samba/pdb_xml.so:filename</command>
(where filename is the name of the file to put the data in)
</para>
<para>
To import data, use:
<command>pdbedit -i plugin:/usr/lib/samba/pdb_xml.so:filename -e current-pdb</command>
Where filename is the name to read the data from and current-pdb to put it in.
</para>
</sect2>
</sect1>
</chapter>
|