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diff --git a/docs/docbook/projdoc/Samba-LDAP-HOWTO.sgml b/docs/docbook/projdoc/Samba-LDAP-HOWTO.sgml new file mode 100644 index 0000000000..f294ddd1ff --- /dev/null +++ b/docs/docbook/projdoc/Samba-LDAP-HOWTO.sgml @@ -0,0 +1,593 @@ +<chapter id="samba-ldap-howto"> + +<chapterinfo> + <author> + <firstname>Gerald (Jerry)</firstname><surname>Carter</surname> + <affiliation> + <orgname>Samba Team</orgname> + <address><email>jerry@samba.org</email></address> + </affiliation> + <firstname>Olivier (lem)</firstname><surname>Lemaire</surname> + <affiliation> + <orgname>IDEALX</orgname> + <address><email>olem@IDEALX.org</email></address> + </affiliation> + </author> + + + <pubdate> (13 Jan 2002) </pubdate> +</chapterinfo> + +<title>Storing Samba's User/Machine Account information in an LDAP Directory</title> + +<sect1> +<title>Purpose</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> + +</sect1> + + +<sect1> +<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> + +</sect1> + +<sect1> +<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> + +</sect1> + + + + +<sect1> +<title>Schema and Relationship to the RFC 2307 posixAccount</title> + + +<para> +Samba 2.2.3 includes the necessary schema file for OpenLDAP 2.0 in +<filename>examples/LDAP/samba.schema</filename>. (Note that this schema +file has been modified since the experimental support initially included +in 2.2.2). 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> +</sect1> + +<sect1> +<title>Configuring Samba with LDAP</title> + + +<sect2> +<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> +</sect2> + + +<sect2> +<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> + + +</sect2> +</sect1> + + +<sect1> +<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 2.2.3, the group management system is based on posix +groups. This meand that Samba make usage of the posixGroup objectclass. +For now, there is no NT-like group system management (global and local +groups). +</para> + +</sect1> + +<sect1> +<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> + + +</sect1> + + + +<sect1> +<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> + + +</sect1> + + + +<sect1> +<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> + + +</sect1> + + + +<sect1> +<title>Comments</title> + + +<para> +Please mail all comments regarding this HOWTO to <ulink +url="mailto:jerry@samba.org">jerry@samba.org</ulink>. This documents was +last updated to reflect the Samba 2.2.3 release. + +</para> + + +</sect1> + + +</chapter> |