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Debian Samba 3 / LDAP / PHP LDAP Admin HOWTO

This was written while I was working for Kangare Software Engineering in Kiribati. This document details how to install and configure a working Samba 3 / LDAP system on Debian Sarge. Much of this applies to other distros as well, I use a similar setup for Fedora 3 for instance.

This is a work in progress. It's not entirely completed yet.
This describes the simplest case: LDAP, Samba and PHP LDAP Admin are running on the same host, so no attempt at security is made.

Prerequisites

Other Documentation:

There is excellent documentation in the samba-doc package (/usr/share/doc/samba-doc/htmldocs/). In particular read the Samba-Guide.

Network Setup

Software

We're going to use the following:

Procedure

Installing Slapd

  1. Install the LDAP server:
    $ apt-get install slapd
    Answer the following questions:
    DNS domain name: nomis52.net
    Name of organisation: Nomis52.net
    Admin password: password
    Confirm password: password
    Allow LDAP v2: yes
    
  2. I'm only allowing LDAP v2 here because I authenticate web users against LDAP with Apache 1.3. If you don't intend to do this, you can safely turn it off.

Installing phpldapadmin

  1. Phpldapadmin requires a webserver to work. If this is a new install, we'll need to install apache. If you already have apache installed skip this step.

    We're using apache-ssl here as we don't want our admin LDAP password being sent over the network in clear text.
    $ apt-get install apache-ssl

    And answer with the following

    Enable SuExec: no
    Country Name: AU
    State: WA
    Locality: Perth
    Organisation Name: Nomis52.net
    Organisational Unit Name: Home
    Host Name:	debian.nomis52.net
    Contact Email: root@nomis52.net
    
  2. Next we install phpldapadmin which provides a web interface for managing information in LDAP

    $ apt-get install phpldapadmin
    And use the following to answer the questions
    Authentication type: session
    Configure webserver: apache-ssl
    Restart: yes
    
  3. Phpldapadmin requires a utility called mkntpwd to create the Samba password hashes. This used to be included in smbldap-tools but doesn't appear to be included in Debian (there is a ITP here) .

    You can download mkntpwd.tar.gz. Then run the following:

    You'll need the following packages installed: make, gcc and libc-dev.
    $ tar -zxf mkntpwd.tar.gz $ cd mkntpwd $ make $ cp mkntpwd /usr/local/bin

    Check by running:

    $ mkntpwd

    And you should get the help message displayed

Installing Samba

  1. Now install samba and the samba-doc package

    $ apt-get install samba samba-doc

    And answer with the following:

    Domain Name: nomis52
    Use Password Encryption: Yes
    Modify smb.conf to use WINS settings via DHCP: No
    How to run Samba: daemons
    Create password database: Yes
    

Configuring and Populating LDAP

  1. slapd needs the Samba schema to work. Do the following:

    $ cd /usr/share/doc/samba-doc/examples/LDAP $ gunzip samba.schema.gz $ cp samba.schema /etc/ldap/schema/

    Now add the following line to /etc/ldap/slapd.conf after the other includes:

    include /etc/ldap/schema/samba.schema

    And restart slapd:

    $ /etc/init.d/slapd restart
  2. We now need to create containers in LDAP for our users, groups and machines. Log into phpldapadmin by going to https://debian.nomis52.net/phpldapadmin/ (obviously insert your address here).

    Login with the password for the admin LDAP user.

    Expand the root of the tree, then click "Create New Entry Here"

    Select "Organizational Unit" (ou):

    Call the ou "users":

    And confirm.

    Then repeat the steps, adding two more ou's called groups and machines. You're tree should now look something like so:

Configuring Samba

  1. Time now to configure Samba. Open the /etc/samba/smb.conf file and find the line:

    passdb backend = tdbsam guest

    This needs to be replaced with the following

    passdb backend = ldapsam:ldap://127.0.0.1 ldap suffix = dc=nomis52,dc=net ldap machine suffix = ou=machines ldap user suffix = ou=users ldap group suffix = ou=groups ldap admin dn = cn=admin,dc=nomis52,dc=net ldap delete dn = no # be a PDC domain logons = yes # allow user privileges enable privileges = yes
  2. Run testparm to make sure the Samba config doesn't contain any errors.
  3. Provide Samba with the root LDAP password like so:

    $ smbpasswd -w password
  4. Restart Samba:

    $/etc/init.d/samba restart
  5. Take a look a phpldapadmin, and you should see that an entry sambaDomainName=NOMIS52 has been created as below:

    Copy the value of sambaSID (eg S-1-5-21-2620819820-906013693-4274777306 ), we'll need it in the next section.

Configure Phpldapadmin

  1. Edit the file /usr/share/phpldapadmin/templates/template_config.php . Find the lines that look like:

    // uncomment to set the base dn of posix groups // default is set to the base dn of the server //$base_posix_groups="ou=People,dc=example,dc=com"; $samba3_domains[] = array( 'name' => 'My Samba domain Name', 'sid' => 'S-1-5-21-4147564533-719371898-3834029857' ); // The base dn of samba group. (CUSTOMIZE) //$samba_base_groups = "ou=Groups,ou=samba,dc=example,dc=org";

    and change it to:

    // uncomment to set the base dn of posix groups // default is set to the base dn of the server $base_posix_groups="ou=groups,dc=nomis52,dc=net"; $samba3_domains[] = array( 'name' => 'nomis52', 'sid' => 'S-1-5-21-2620819820-906013693-4274777306' ); // The base dn of samba group. (CUSTOMIZE) $samba_base_groups = "ou=groups,dc=nomis52,dc=net";

    Where the sid was the one obtained from phpldapadmin above.

Add Default Groups

  1. We need to create some default groups. Using phpladpadmin add the following three Samba 3 Group Mappings under ou=groups:

    Unix name Samba Name gid Samba Sid
    admins Domain Admins 20000 Built-In -> Domain Admins
    users Domain Users 20001 Built-In -> Domain Users
    guests Domain Guests 20002 Built-In -> Domain Guests

    The example below shows the admins group being created:

Setting up Unix Authentication

Next we want to set up the Linux machine so that LDAP users appear as 'normal' Unix users.

  1. Install the libnss-ldap package and configure:

    $ apt-get install libnss-ldap
    LDAP Server Host: 127.0.0.1
    DN of Search Base: dc=nomis52,dc=net
    LDAP Version: 3
    Database requires login: no
    Make config readable by owner only: yes
    
  2. Edit the file /etc/nsswitch.conf to look like the following:

    passwd: compat ldap group: compat ldap shadow: compat ldap

    This will search the local database (/etc/passwd) first, then LDAP. You may want it the other way round. YMMV

  3. Now use the getent utility to confirm that the groups created above show up:

    $ getent group ssh:x:103: users:x:20001: guests:x:20002: admins:x:20000: ...
  4. Install the libpam-ldap package

    $ apt-get install libpam-ldap
    Make local root db admin: yes
    Database requires logging in : no
    Root login account : cn=admin,dc=nomis52,dc=net
    Root password : password
    Crypt : MD5
    
  5. Samba requires an Administrator user (with a uidNumber of 0) to join Windows machines to the domain. I don't like having a root user in LDAP able to logon to the Linux workstations, so I add a filter to /etc/pam_ldap.conf . If you don't mind this (or want a single root account over all the machines) skip this step.

    Add the following line to /etc/pam-ldap.conf

    pam_filter !(uidNumber=0)

    Which does not allow a user with a uidNumber of 0 to login using LDAP

  6. The following files need to be edited to configure PAM for LDAP:

    /etc/pam.d/common-account

    # Comment out the next line #account required pam_unix.so # and add these two account sufficient pam_ldap.so account required pam_unix.so try_first_pass

    /etc/pam.d/common-auth

    # comment out the next line #auth required pam_unix.so nullok_secure # and add these two auth sufficient pam_ldap.so auth required pam_unix.so nullok_secure use_first_pass

    /etc/pam.d/common-password

    # comment out the next line #password required pam_unix.so nullok obscure min=4 max=8 md5 # and add these two password sufficient pam_ldap.so password required pam_unix.so nullok obscure min=4 max=8 md5 use_first_pass
  7. At this point you probably want to restart ssh and samba

    $ /etc/init.d/ssh restart $ /etc/init.d/samba restart
  8. Finally install the name service caching daemon:

    $apt-get install nscd

Add Users

  1. Ok now we can finally add some users. You'll need an Administrator (uid=0) and at least one other user. Create a new Samba 3 User(s) under ou=users like so:

    Uid First Name User Name User Password Encryption Windows Group
    0 Admin Administrator password MD5 Domain Admins
    10000 Simon simon ******** MD5 Domain Admins
  2. At this point we can use getent to verify that nss is working correctly on the Linux system.

    $ getent passwd simon:x:10000:20000:Simon Newton:/home/simon:/bin/bash Administrator:x:0:20000:admin :/home/administrator:/bin/bash ...
  3. Finally we need to add home directories for our users:

    $ mkdir /home/simon $ cp /etc/skel/.* /home/simon/ $ chown -R simon /home/simon $ chgrp -R users /home/simon

Testing

  1. First try logging in (at the console or via ssh) with a LDAP user.

  2. Then try connecting to the Samba server. If you have problems check the Samba log files in /var/log/samba (/var/log/samba/log.machinename would be a good place to start).

Creating Shares and Assigning Rights

Todo

Joining Machines to the Domain

You've got two options here; either we can add machines manually into LDAP, or we can setup a script to add them automatically (my preferred option).

Manual

  1. Create a Samba 3 NT Machine under ou=machines in LDAP. Use the following:

    Machine Name UID Number
    quigon 30000

    Where "quigon" is the name of the Windows machine. I start the machine's uid numbers from 30000. You'll need to do this for every workstation in use.

Automatic

  1. Install the following Perl Modules:

    $ apt-get install libnet-ldap-perl libcrypt-smbhash-perl
  2. Copy the smbldap-useradd script (and the config files) from the Samba-doc package. I put this in /usr/local/smbldaptools

    $ mkdir /usr/local/smbldaptools $ cd /usr/share/doc/samba-doc/LDAP/examples/smbldaptools/ $ cp smbldap_bind.conf smbldap_tools.pm.gz smbldap.conf.gz smbldap-useradd.gz /usr/local/smbldaptools/ $ gunzip /usr/local/smbldaptools/*.gz $ cd /usr/local/smbldaptools $ chmod go-r * $ chmod u+x smbldap-useradd

    Edit the /usr/local/smbldaptools/smbldap.conf file to look something like this (the lines I changed are below):

    SID="S-1-5-21-3131077580-1338128831-1697195685" suffix="dc=nomis52,dc=net" usersdn="ou=users,${suffix}" computersdn="ou=machines,${suffix}" groupsdn="ou=groups,${suffix}" sambaUnixIdPooldn="sambaDomainName=NOMIS52,${suffix}" hash_encrypt="MD5"

    Edit /usr/local/smbldaptools/smbldap_bind.conf:

    slaveDN="cn=admin,dc=nomis52,dc=net" slavePw="password" masterDN="cn=admin,dc=nomis52,dc=net" masterPw="password"

    Edit /usr/local/smbldaptools/smbldap_tools.pm to point to the correct config file:

    my $smbldap_conf="/usr/local/smbldaptools/smbldap.conf"; my $smbldap_bind_conf="/usr/local/smbldaptools/smbldap_bind.conf";
  3. Browse to the sambaDomainName=NOMIS52 object in phpldapadmin. Click on add value under the object class attributes and choose sambaUnixIdPool. Click next and then enter a starting uid and gid number. (In this case the gid number won't be used. I start my machine accounts at 30000.

  4. Test out the script by running:

    $./smbldap-useradd -w "quigon"

    It should return without printing any output.

    If that works, go and delete the new object uid=quigon$ in the machines ou. Also you may want to reset the uidNumber in the sambaDomainName=NOMIS52 object to 30000 (it will have been updated to 30001 now) .

  5. Finally add the following to the smb.conf file:

    add machine script = /usr/local/smbldaptools/smbldap-useradd -w "%u"
  6. Lastly, often we want to allow a normal user(s) to add machines to the domain. We can grant a user the rights to add machines to the domain using the following (done on the Linux machine):

    net rpc -UAdministrator rights grant simon SeMachineAccountPrivilege

    This grants the user "simon" the rights to join machines to the domain. If you get an error back like:

    Failed to grant privileges for simon (NT_STATUS_NO_SUCH_PRIVILEGE)

    it means you don't have enable privileges = yes in your smb.conf file

Password Changes

It would be nice to allow users to change thier LDAP passwords from Windows. Some documentation makes use of the smbldap-password script to do this, but I've found adding:

ldap password sync = yes

to the smb.conf file works fine

Logon Scripts

I use KiXtart to write the logon scripts.

  1. Create a netlogon share, and give the admins group write access to it

    $ mkdir /data/samba/netlogon $ chgrp admins /data/samba/netlogon

    Add the following to smb.conf:

    # put this in the main section logon script = logon.bat # share for the logon scripts [netlogon] comment = Network logon service path = /data/samba/netlogon write list = "@admins" guest ok = Yes
  2. Logon to a Windows machine as a user in the Domain Admins group. You should have write access to the netlogon share. Download KiXstart, extract, and put the following files into the netlogon share:

    • KIX32.EXE
    • KX32.DLL
  3. Create a logon.bat in the netlogon share. You need to edit this from Windows to get the carriage returns in DOS style rather than *nix style.

    \\debian\netlogon\kix32 \\debian\netlogon\logon.kix /f
  4. Create a file logon.kix. This will get executed when user's logon. You can mount shares, sync the time etc. Here is an example

    ; logon script for nomis52.net setconsole('hide') ; delete all mapped drives USE * /delete ; sync time $timeserver = "\\debian" Settime $timeserver IF INGROUP("NOMIS52\Domain Admins") use n: \\debian\netlogon ENDIF ; add more drive mappings here ; map homedirectory use u: @HOMEDIR
  5. Logoff and login again, and check that the script is working. If it doesn't work you can run the script as a user with debug mode turned on. See the Kixtart docsumentation for more details.

Roaming Profiles

Work in progress..
[profiles] path = /data/samba/profiles comment = Profiles read only = no browseable = yes profile acls = Yes browsable = no root preexec = /etc/samba/scripts/mk_profile "%u"

We also want to hide those annoying desktop.ini files, and the RECYCLER folder that gets created on network shares. You can get Samba to set the hidden attribute on these files with the following.

hide files = /desktop.ini/RECYCLER/

Hiding Samba Password Hashes

By default the attributes sambaLMPassword and sambaNTPassword are accessible to all users (even anonymous ones). If you're not happy about this you can restrict access to the admin user and the user that owns the object by changing the lines in /etc/ldap/slapd.conf from :

access to attrs=userPassword by dn="cn=admin,dc=nomis52,dc=net" write by anonymous auth by self write by * none
to
access to attrs=userPassword,sambaLMPassword,sambaNTPassword by dn="cn=admin,dc=nomis52,dc=net" write by anonymous auth by self write by * none