Ubuntu 11.04安装配置 OpenLDAP
LDAP is an acronym for Lightweight Directory Access Protocol, it is a simplified version of the X.500 protocol. The directory setup in this section will be used for authentication. Nevertheless, LDAP can be used in numerous ways: authentication, shared directory (for mail clients), address book, etc.
To describe LDAP quickly, all information is stored in a tree structure. With OpenLDAP you have freedom to determine the directory arborescence (the Directory Information Tree: the DIT) yourself. We will begin with a basic tree containing two nodes below the root:
"People" node where your users will be stored
"Groups" node where your groups will be stored
Before beginning, you should determine what the root of your LDAP directory will be. By default, your tree will be determined by your Fully Qualified Domain Name (FQDN). If your domain is example.com (which we will use in this example), your root node will be dc=example,dc=com.
Installation
First, install the OpenLDAP server daemon slapd and ldap-utils, a package containing LDAP management utilities:
sudo apt-get install slapd ldap-utils
By default slapd is configured with minimal options needed to run the slapd daemon.
The configuration example in the following sections will match the domain name of the server. For example, if the machine's Fully Qualified Domain Name (FQDN) is ldap.example.com, the default suffix will be dc=example,dc=com.
Populating LDAP
OpenLDAP uses a separate directory which contains the cn=config Directory Information Tree (DIT). The cn=config DIT is used to dynamically configure the slapd daemon, allowing the modification of schema definitions, indexes, ACLs, etc without stopping the service.
The backend cn=config directory has only a minimal configuration and will need additional configuration options in order to populate the frontend directory. The frontend will be populated with a "classical" scheme that will be compatible with address book applications and with Unix Posix accounts. Posix accounts will allow authentication to various applications, such as web applications, email Mail Transfer Agent (MTA) applications, etc.
For external applications to authenticate using LDAP they will each need to be specifically configured to do so. Refer to the individual application documentation for details. |
Remember to change dc=example,dc=com in the following examples to match your LDAP configuration. |
First, some additional schema files need to be loaded. In a terminal enter:
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/ldap/schema/cosine.ldif sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/ldap/schema/nis.ldif sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/ldap/schema/inetorgperson.ldif
Next, copy the following example LDIF file, naming it backend.example.com.ldif, somewhere on your system:
# Load dynamic backend modules
dn: cn=module,cn=config
objectClass: olcModuleList
cn: module
olcModulepath: /usr/lib/ldap
olcModuleload: back_hdb.la
# Database settings
dn: olcDatabase=hdb,cn=config
objectClass: olcDatabaseConfig
objectClass: olcHdbConfig
olcDatabase: {1}hdb
olcSuffix: dc=example,dc=com
olcDbDirectory: /var/lib/ldap
olcRootDN: cn=admin,dc=example,dc=com
olcRootPW: secret
olcDbConfig: set_cachesize 0 2097152 0
olcDbConfig: set_lk_max_objects 1500
olcDbConfig: set_lk_max_locks 1500
olcDbConfig: set_lk_max_lockers 1500
olcDbIndex: objectClass eq
olcLastMod: TRUE
olcDbCheckpoint: 512 30
olcAccess: to attrs=userPassword by dn="cn=admin,dc=example,dc=com" write by anonymous auth by self write by * none
olcAccess: to attrs=shadowLastChange by self write by * read
olcAccess: to dn.base="" by * read
olcAccess: to * by dn="cn=admin,dc=example,dc=com" write by * read
Change olcRootPW: secret to a password of your choosing. |
Now add the LDIF to the directory:
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f backend.example.com.ldif
The frontend directory is now ready to be populated. Create a frontend.example.com.ldif with the following contents:
# Create top-level object in domain dn: dc=example,dc=com objectClass: top objectClass: dcObject objectclass: organization o: Example Organization dc: Example description: LDAP Example # Admin user. dn: cn=admin,dc=example,dc=com objectClass: simpleSecurityObject objectClass: organizationalRole cn: admin description: LDAP administrator userPassword: secret dn: ou=people,dc=example,dc=com objectClass: organizationalUnit ou: people dn: ou=groups,dc=example,dc=com objectClass: organizationalUnit ou: groups dn: uid=john,ou=people,dc=example,dc=com objectClass: inetOrgPerson objectClass: posixAccount objectClass: shadowAccount uid: john sn: Doe givenName: John cn: John Doe displayName: John Doe uidNumber: 1000 gidNumber: 10000 userPassword: password gecos: John Doe loginShell: /bin/bash homeDirectory: /home/john shadowExpire: -1 shadowFlag: 0 shadowWarning: 7 shadowMin: 8 shadowMax: 999999 shadowLastChange: 10877 mail: [email protected] postalCode: 31000 l: Toulouse o: Example mobile: +33 (0)6 xx xx xx xx homePhone: +33 (0)5 xx xx xx xx title: System Administrator postalAddress: initials: JD dn: cn=example,ou=groups,dc=example,dc=com objectClass: posixGroup cn: example gidNumber: 10000
In this example the directory structure, a user, and a group have been setup. In other examples you might see theobjectClass: top added in every entry, but that is the default behaviour so you do not have to add it explicitly.
Add the entries to the LDAP directory:
sudo ldapadd -x -D cn=admin,dc=example,dc=com -W -f frontend.example.com.ldif
We can check that the content has been correctly added with the ldapsearch utility. Execute a search of the LDAP directory:
ldapsearch -xLLL -b "dc=example,dc=com" uid=john sn givenName cn
dn: uid=john,ou=people,dc=example,dc=com
cn: John Doe
sn: Doe
givenName: John
Just a quick explanation:
-x: will not use SASL authentication method, which is the default.
-LLL: disable printing LDIF schema information.
Further Configuration
The cn=config tree can be manipulated using the utilities in the ldap-utils package. For example:
Use ldapsearch to view the tree, entering the admin password set during installation or reconfiguration:
sudo ldapsearch -LLL -Y EXTERNAL -H ldapi:/// -b cn=config dnSASL/EXTERNAL authentication started SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth SASL SSF: 0 dn: cn=config dn: cn=module{0},cn=config dn: cn=schema,cn=config dn: cn={0}core,cn=schema,cn=config dn: cn={1}cosine,cn=schema,cn=config dn: cn={2}nis,cn=schema,cn=config dn: cn={3}inetorgperson,cn=schema,cn=config dn: olcDatabase={-1}frontend,cn=config dn: olcDatabase={0}config,cn=config dn: olcDatabase={1}hdb,cn=configThe output above is the current configuration options for the cn=config backend database. Your output may be vary.
As an example of modifying the cn=config tree, add another attribute to the index list using ldapmodify:
sudo ldapmodify -Y EXTERNAL -H ldapi:///SASL/EXTERNAL authentication started SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth SASL SSF: 0dn: olcDatabase={1}hdb,cn=config add: olcDbIndex olcDbIndex: uidNumber eqmodifying entry "olcDatabase={1}hdb,cn=config"Once the modification has completed, press Ctrl+D to exit the utility.
ldapmodify can also read the changes from a file. Copy and paste the following into a file named
uid_index.ldif:dn: olcDatabase={1}hdb,cn=config add: olcDbIndex olcDbIndex: uid eq,pres,subThen execute ldapmodify:
sudo ldapmodify -Y EXTERNAL -H ldapi:/// -f uid_index.ldifSASL/EXTERNAL authentication started SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth SASL SSF: 0 modifying entry "olcDatabase={1}hdb,cn=config"The file method is very useful for large changes.
Adding additional schemas to slapd requires the schema to be converted to LDIF format. The
/etc/ldap/schemadirectory contains some schema files already converted to LDIF format as demonstrated in the previous section. Fortunately, the slapd program can be used to automate the conversion. The following example will add thedyngroup.schema:First, create a conversion
schema_convert.conffile containing the following lines:include /etc/ldap/schema/core.schema include /etc/ldap/schema/collective.schema include /etc/ldap/schema/corba.schema include /etc/ldap/schema/cosine.schema include /etc/ldap/schema/duaconf.schema include /etc/ldap/schema/dyngroup.schema include /etc/ldap/schema/inetorgperson.schema include /etc/ldap/schema/java.schema include /etc/ldap/schema/misc.schema include /etc/ldap/schema/nis.schema include /etc/ldap/schema/openldap.schema include /etc/ldap/schema/ppolicy.schema
Next, create a temporary directory to hold the output:
mkdir /tmp/ldif_outputNow using slapcat convert the schema files to LDIF:
slapcat -f schema_convert.conf -F /tmp/ldif_output -n0 -s "cn={5}dyngroup,cn=schema,cn=config" > /tmp/cn=dyngroup.ldifAdjust the configuration file name and temporary directory names if yours are different. It may be worthwhile to keep the
ldif_outputdirectory around in case you want to add additional schemas in the future.The "cn={5}" index number may change according to the configuration ordering. To find out the correct number execute the following:
slapcat -f schema_convert.conf -F /tmp/ldif_output -n 0 | grep dyngroupReplace dyngroup with the appropriate schema name.
Edit the
/tmp/cn\=dyngroup.ldiffile, changing the following attributes:dn: cn=dyngroup,cn=schema,cn=config ... cn: dyngroup
And remove the following lines from the bottom of the file:
structuralObjectClass: olcSchemaConfig entryUUID: 10dae0ea-0760-102d-80d3-f9366b7f7757 creatorsName: cn=config createTimestamp: 20080826021140Z entryCSN: 20080826021140.791425Z#000000#000#000000 modifiersName: cn=config modifyTimestamp: 20080826021140Z
The attribute values will vary, just be sure the attributes are removed.
Finally, using the ldapadd utility, add the new schema to the directory:
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /tmp/cn\=dyngroup.ldif
There should now be a dn: cn={4}dyngroup,cn=schema,cn=config entry in the cn=config tree.
LDAP Replication
LDAP often quickly becomes a highly critical service to the network. Multiple systems will come to depend on LDAP for authentication, authorization, configuration, etc. It is a good idea to setup a redundant system through replication.
Replication is achieved using the Syncrepl engine. Syncrepl allows the changes to be synced using a consumer, providermodel. A provider sends directory changes to consumers.
Provider Configuration
The following is an example of a Single-Master configuration. In this configuration one OpenLDAP server is configured as aprovider and another as a consumer.
First, configure the provider server. Copy the following to a file named
provider_sync.ldif:# Add indexes to the frontend db. dn: olcDatabase={1}hdb,cn=config changetype: modify add: olcDbIndex olcDbIndex: entryCSN eq - add: olcDbIndex olcDbIndex: entryUUID eq #Load the syncprov and accesslog modules. dn: cn=module{0},cn=config changetype: modify add: olcModuleLoad olcModuleLoad: syncprov - add: olcModuleLoad olcModuleLoad: accesslog # Accesslog database definitions dn: olcDatabase={2}hdb,cn=config objectClass: olcDatabaseConfig objectClass: olcHdbConfig olcDatabase: {2}hdb olcDbDirectory: /var/lib/ldap/accesslog olcSuffix: cn=accesslog olcRootDN: cn=admin,dc=example,dc=com olcDbIndex: default eq olcDbIndex: entryCSN,objectClass,reqEnd,reqResult,reqStart # Accesslog db syncprov. dn: olcOverlay=syncprov,olcDatabase={2}hdb,cn=config changetype: add objectClass: olcOverlayConfig objectClass: olcSyncProvConfig olcOverlay: syncprov olcSpNoPresent: TRUE olcSpReloadHint: TRUE # syncrepl Provider for primary db dn: olcOverlay=syncprov,olcDatabase={1}hdb,cn=config changetype: add objectClass: olcOverlayConfig objectClass: olcSyncProvConfig olcOverlay: syncprov olcSpNoPresent: TRUE # accesslog overlay definitions for primary db dn: olcOverlay=accesslog,olcDatabase={1}hdb,cn=config objectClass: olcOverlayConfig objectClass: olcAccessLogConfig olcOverlay: accesslog olcAccessLogDB: cn=accesslog olcAccessLogOps: writes olcAccessLogSuccess: TRUE # scan the accesslog DB every day, and purge entries older than 7 days olcAccessLogPurge: 07+00:00 01+00:00The AppArmor profile for slapd will need to be adjusted for the accesslog database location. Edit
/etc/apparmor.d/usr.sbin.slapdadding:/var/lib/ldap/accesslog/ r, /var/lib/ldap/accesslog/** rwk,
Then create the directory, reload the apparmor profile, and copy the
DB_CONFIGfile:sudo -u openldap mkdir /var/lib/ldap/accesslog sudo -u openldap cp /var/lib/ldap/DB_CONFIG /var/lib/ldap/accesslog/ sudo /etc/init.d/apparmor reload
Using the -u openldap option with the sudo commands above removes the need to adjust permissions for the new directory later.
Edit the file and change the olcRootDN to match your directory:
olcRootDN: cn=admin,dc=example,dc=com
Next, add the LDIF file using the ldapadd utility:
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f provider_sync.ldifRestart slapd:
sudo /etc/init.d/slapd restart
The Provider server is now configured, and it is time to configure a Consumer server.
Consumer Configuration
On the Consumer server configure it the same as the Provider except for the Syncrepl configuration steps.
Add the additional schema files:
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/ldap/schema/cosine.ldif sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/ldap/schema/nis.ldif sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/ldap/schema/inetorgperson.ldif
Also, create, or copy from the provider server, the
backend.example.com.ldif# Load dynamic backend modules dn: cn=module,cn=config objectClass: olcModuleList cn: module olcModulepath: /usr/lib/ldap olcModuleload: back_hdb.la # Database settings dn: olcDatabase=hdb,cn=config objectClass: olcDatabaseConfig objectClass: olcHdbConfig olcDatabase: {1}hdb olcSuffix: dc=example,dc=com olcDbDirectory: /var/lib/ldap olcRootDN: cn=admin,dc=example,dc=com olcRootPW: secret olcDbConfig: set_cachesize 0 2097152 0 olcDbConfig: set_lk_max_objects 1500 olcDbConfig: set_lk_max_locks 1500 olcDbConfig: set_lk_max_lockers 1500 olcDbIndex: objectClass eq olcLastMod: TRUE olcDbCheckpoint: 512 30 olcAccess: to attrs=userPassword by dn="cn=admin,dc=example,dc=com" write by anonymous auth by self write by * none olcAccess: to attrs=shadowLastChange by self write by * read olcAccess: to dn.base="" by * read olcAccess: to * by dn="cn=admin,dc=example,dc=com" write by * readAnd add the LDIF by entering:
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f backend.example.com.ldifDo the same with the
frontend.example.com.ldiffile listed above, and add it:sudo ldapadd -x -D cn=admin,dc=example,dc=com -W -f frontend.example.com.ldifThe two severs should now have the same configuration except for the Syncrepl options.
Now create a file named
consumer_sync.ldifcontaining:#Load the syncprov module. dn: cn=module{0},cn=config changetype: modify add: olcModuleLoad olcModuleLoad: syncprov # syncrepl specific indices dn: olcDatabase={1}hdb,cn=config changetype: modify add: olcDbIndex olcDbIndex: entryUUID eq - add: olcSyncRepl olcSyncRepl: rid=0 provider=ldap://ldap01.example.com bindmethod=simple binddn="cn=admin,dc=example,dc=com" credentials=secret searchbase="dc=example,dc=com" logbase="cn=accesslog" logfilter="(&(objectClass=auditWriteObject)(reqResult=0))" schemachecking=on type=refreshAndPersist retry="60 +" syncdata=accesslog - add: olcUpdateRef olcUpdateRef: ldap://ldap01.example.comYou will probably want to change the following attributes:
ldap01.example.com to your server's hostname.
binddn
credentials
searchbase
olcUpdateRef:
Add the LDIF file to the configuration tree:
sudo ldapadd -c -Y EXTERNAL -H ldapi:/// -f consumer_sync.ldif
The frontend database should now sync between servers. You can add additional servers using the steps above as the need arises.
The slapd daemon will send log information to 127.0.0.1 ldap01.example.com ldap01 . |
Setting up ACL
Authentication requires access to the password field, that should be not accessible by default. Also, in order for users to change their own password, using passwd or other utilities, shadowLastChange needs to be accessible once a user has authenticated.
To view the Access Control List (ACL) for the cn=config tree, use the ldapsearch utility:
sudo ldapsearch -c -Y EXTERNAL -H ldapi:/// -LLL -b cn=config olcDatabase=config olcAccess
SASL/EXTERNAL authentication started
SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
SASL SSF: 0
dn: olcDatabase={0}config,cn=config
olcAccess: {0}to * by dn.exact=gidNumber=0+uidNumber=0,cn=peercred,cn=external
,cn=auth manage by * break
To see the ACL for the frontend tree enter:
sudo ldapsearch -c -Y EXTERNAL -H ldapi:/// -LLL -b cn=config olcDatabase={1}hdb olcAccess
TLS and SSL
When authenticating to an OpenLDAP server it is best to do so using an encrypted session. This can be accomplished using Transport Layer Security (TLS) and/or Secure Sockets Layer (SSL).
The first step in the process is to obtain or create a certificate. Because slapd is compiled using the gnutls library, thecerttool utility will be used to create certificates.
First, install gnutls-bin by entering the following in a terminal:
sudo apt-get install gnutls-binNext, create a private key for the Certificate Authority (CA):
sudo sh -c "certtool --generate-privkey > /etc/ssl/private/cakey.pem"Create a
/etc/ssl/ca.infodetails file to self-sign the CA certificate containing:cn = Example Company ca cert_signing_key
Now create the self-signed CA certificate:
sudo certtool --generate-self-signed --load-privkey /etc/ssl/private/cakey.pem \ --template /etc/ssl/ca.info --outfile /etc/ssl/certs/cacert.pemMake a private key for the server:
sudo sh -c "certtool --generate-privkey > /etc/ssl/private/ldap01_slapd_key.pem"Replace ldap01 in the filename with your server's hostname. Naming the certificate and key for the host and service that will be using them will help keep filenames and paths straight.
To sign the server's certificate with the CA, create the
/etc/ssl/ldap01.infoinfo file containing:organization = Example Company cn = ldap01.example.com tls_www_server encryption_key signing_key
Create the server's certificate:
sudo certtool --generate-certificate --load-privkey /etc/ssl/private/ldap01_slapd_key.pem \ --load-ca-certificate /etc/ssl/certs/cacert.pem --load-ca-privkey /etc/ssl/private/cakey.pem \ --template /etc/ssl/ldap01.info --outfile /etc/ssl/certs/ldap01_slapd_cert.pem
Once you have a certificate, key, and CA cert installed, use ldapmodify to add the new configuration options:
sudo ldapmodify -Y EXTERNAL -H ldapi:///
Enter LDAP Password:
dn: cn=config
add: olcTLSCACertificateFile
olcTLSCACertificateFile: /etc/ssl/certs/cacert.pem
-
add: olcTLSCertificateFile
olcTLSCertificateFile: /etc/ssl/certs/ldap01_slapd_cert.pem
-
add: olcTLSCertificateKeyFile
olcTLSCertificateKeyFile: /etc/ssl/private/ldap01_slapd_key.pem
modifying entry "cn=config"
Adjust the |
Next, edit /etc/default/slapd uncomment the SLAPD_SERVICES option:
SLAPD_SERVICES="ldap:/// ldapi:/// ldaps:///"
Now the openldap user needs access to the certificate:
sudo adduser openldap ssl-cert sudo chgrp ssl-cert /etc/ssl/private/ldap01_slapd_key.pem sudo chmod g+r /etc/ssl/private/ldap01_slapd_key.pem
If the |
Finally, restart slapd:
sudo /etc/init.d/slapd restart
The slapd daemon should now be listening for LDAPS connections and be able to use STARTTLS during authentication.
If you run into troubles with the server not starting, check the /var/log/syslog. If you see errors like main: TLS init def ctx failed: -1, it is likely there is a configuration problem. Check that the certificate is signed by the authority from in the files configured, and that the ssl-cert group has read permissions on the private key. |
TLS Replication
If you have setup Syncrepl between servers, it is prudent to encrypt the replication traffic using Transport Layer Security (TLS). For details on setting up replication see the section called “LDAP Replication”.
Assuming you have followed the above instructions and created a CA certificate and server certificate on the Provider server. Follow the following instructions to create a certificate and key for the Consumer server.
Create a new key for the Consumer server:
mkdir ldap02-ssl cd ldap02-ssl certtool --generate-privkey > ldap02_slapd_key.pem
Creating a new directory is not strictly necessary, but it will help keep things organized and make it easier to copy the files to the Consumer server.
Next, create an info file,
ldap02.infofor the Consumer server, changing the attributes to match your locality and server:country = US state = North Carolina locality = Winston-Salem organization = Example Company cn = ldap02.salem.edu tls_www_client encryption_key signing_key
Create the certificate:
sudo certtool --generate-certificate --load-privkey ldap02_slapd_key.pem \ --load-ca-certificate /etc/ssl/certs/cacert.pem --load-ca-privkey /etc/ssl/private/cakey.pem \ --template ldap02.info --outfile ldap02_slapd_cert.pemCopy the
cacert.pemto the directory:cp /etc/ssl/certs/cacert.pem .The only thing left is to copy the
ldap02-ssldirectory to the Consumer server, then copyldap02_slapd_cert.pemandcacert.pemto/etc/ssl/certs, and copyldap02_slapd_key.pemto/etc/ssl/private.Once the files are in place adjust the cn=config tree by entering:
sudo ldapmodify -Y EXTERNAL -H ldapi:///Enter LDAP Password:dn: cn=config add: olcTLSCACertificateFile olcTLSCACertificateFile: /etc/ssl/certs/cacert.pem - add: olcTLSCertificateFile olcTLSCertificateFile: /etc/ssl/certs/ldap02_slapd_cert.pem - add: olcTLSCertificateKeyFile olcTLSCertificateKeyFile: /etc/ssl/private/ldap02_slapd_key.pemmodifying entry "cn=config"As with the Provider you can now edit
/etc/default/slapdand add the ldaps:/// parameter to the SLAPD_SERVICESoption.
Now that TLS has been setup on each server, once again modify the Consumer server's cn=config tree by entering the following in a terminal:
sudo ldapmodify -Y EXTERNAL -H ldapi:///
SASL/EXTERNAL authentication started
SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
SASL SSF: 0
dn: olcDatabase={1}hdb,cn=config
replace: olcSyncrepl
olcSyncrepl: {0}rid=0 provider=ldap://ldap01.example.com bindmethod=simple binddn="cn=ad
min,dc=example,dc=com" credentials=secret searchbase="dc=example,dc=com" logbas
e="cn=accesslog" logfilter="(&(objectClass=auditWriteObject)(reqResult=0))" s
chemachecking=on type=refreshAndPersist retry="60 +" syncdata=accesslog starttls=yes
modifying entry "olcDatabase={1}hdb,cn=config"
If the LDAP server hostname does not match the Fully Qualified Domain Name (FQDN) in the certificate, you may have to edit/etc/ldap/ldap.conf and add the following TLS options:
TLS_CERT /etc/ssl/certs/ldap02_slapd_cert.pem TLS_KEY /etc/ssl/private/ldap02_slapd_key.pem TLS_CACERT /etc/ssl/certs/cacert.pem
Finally, restart slapd on each of the servers:
sudo /etc/init.d/slapd restart
LDAP Authentication
Once you have a working LDAP server, the auth-client-config and libnss-ldap packages take the pain out of configuring an Ubuntu client to authenticate using LDAP. To install the packages from, a terminal prompt enter:
sudo apt-get install libnss-ldap
During the install a menu dialog will ask you connection details about your LDAP server.
If you make a mistake when entering your information you can execute the dialog again using:
sudo dpkg-reconfigure ldap-auth-config
The results of the dialog can be seen in /etc/ldap.conf. If your server requires options not covered in the menu edit this file accordingly.
Now that libnss-ldap is configured enable the auth-client-config LDAP profile by entering:
sudo auth-client-config -t nss -p lac_ldap
-t: only modifies
/etc/nsswitch.conf.-p: name of the profile to enable, disable, etc.
lac_ldap: the auth-client-config profile that is part of the ldap-auth-config package.
Using the pam-auth-update utility, configure the system to use LDAP for authentication:
sudo pam-auth-update
From the pam-auth-update menu, choose LDAP and any other authentication mechanisms you need.
You should now be able to login using user credentials stored in the LDAP directory.
If you are going to use LDAP to store Samba users you will need to configure the server to authenticate using LDAP. See the section called “Samba and LDAP” for details. |
User and Group Management
The ldap-utils package comes with multiple utilities to manage the directory, but the long string of options needed, can make them a burden to use. The ldapscripts package contains configurable scripts to easily manage LDAP users and groups.
To install the package, from a terminal enter:
sudo apt-get install ldapscripts
Next, edit the config file /etc/ldapscripts/ldapscripts.conf uncommenting and changing the following to match your environment:
SERVER=localhost BINDDN='cn=admin,dc=example,dc=com' BINDPWDFILE="/etc/ldapscripts/ldapscripts.passwd" SUFFIX='dc=example,dc=com' GSUFFIX='ou=Groups' USUFFIX='ou=People' MSUFFIX='ou=Computers' GIDSTART=10000 UIDSTART=10000 MIDSTART=10000
Now, create the ldapscripts.passwd file to allow authenticated access to the directory:
sudo sh -c "echo -n 'secret' > /etc/ldapscripts/ldapscripts.passwd" sudo chmod 400 /etc/ldapscripts/ldapscripts.passwd
Replace “secret” with the actual password for your LDAP admin user. |
The ldapscripts are now ready to help manage your directory. The following are some examples of how to use the scripts:
Create a new user:
sudo ldapadduser george exampleThis will create a user with uid george and set the user's primary group (gid) to example
Change a user's password:
sudo ldapsetpasswd george
Changing password for user uid=george,ou=People,dc=example,dc=comNew Password:New Password (verify):Delete a user:
sudo ldapdeleteuser georgeAdd a group:
sudo ldapaddgroup qaDelete a group:
sudo ldapdeletegroup qaAdd a user to a group:
sudo ldapaddusertogroup george qaYou should now see a memberUid attribute for the qa group with a value of george.
Remove a user from a group:
sudo ldapdeleteuserfromgroup george qaThe memberUid attribute should now be removed from the qa group.
The ldapmodifyuser script allows you to add, remove, or replace a user's attributes. The script uses the same syntax as the ldapmodify utility. For example:
sudo ldapmodifyuser george
# About to modify the following entry : dn: uid=george,ou=People,dc=example,dc=com objectClass: account objectClass: posixAccount cn: george uid: george uidNumber: 1001 gidNumber: 1001 homeDirectory: /home/george loginShell: /bin/bash gecos: george description: User account userPassword:: e1NTSEF9eXFsTFcyWlhwWkF1eGUybVdFWHZKRzJVMjFTSG9vcHk= # Enter your modifications here, end with CTRL-D. dn: uid=george,ou=People,dc=example,dc=comreplace: gecos gecos: George CarlinThe user's gecos should now be “George Carlin”.
Another great feature of ldapscripts, is the template system. Templates allow you to customize the attributes of user, group, and machine objectes. For example, to enable the user template edit
/etc/ldapscripts/ldapscripts.confchanging:UTEMPLATE="/etc/ldapscripts/ldapadduser.template"
There are sample templates in the
/etc/ldapscriptsdirectory. Copy or rename theldapadduser.template.samplefile to/etc/ldapscripts/ldapadduser.template:sudo cp /usr/share/doc/ldapscripts/examples/ldapadduser.template.sample /etc/ldapscripts/ldapadduser.templateEdit the new template to add the desired attributes. The following will create new user's as with an objectClass ofinetOrgPerson:
dn: uid=
, , objectClass: inetOrgPerson objectClass: posixAccount cn: sn: uid: uidNumber: gidNumber: homeDirectory: loginShell: gecos: description: User account title: Employee Notice the
option used for the ssn value. Using will configure ldapadduser to prompt you for the attribute value during user creation.
There are more useful scripts in the package, to see a full list enter: dpkg -L ldapscripts | grep bin
Resources
The OpenLDAP Ubuntu Wiki page has more details.
For more information see OpenLDAP Home Page
Though starting to show it's age, a great source for in depth LDAP information is O'Reilly's LDAP System Administration
Packt's Mastering OpenLDAP is a great reference covering newer versions of OpenLDAP.
For more information on auth-client-config see the man page: man auth-client-config.
For more details regarding the ldapscripts package see the man pages: man ldapscripts, man ldapadduser, man ldapaddgroup, etc.