Difference between revisions of "OpenLDAP"
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[[Category:Networking]] | [[Category:Networking]] | ||
[[ru:openLDAP]] | [[ru:openLDAP]] | ||
+ | {{Out of date|slapd.conf(5) is deprecated; use slapd-config(5)}} | ||
+ | |||
+ | OpenLDAP is an open-source implementation of the LDAP protocol. It is mainly used as an address book (for e.g. email clients) or authentication backend to various services (the most famous one being Samba, which is used to emulate a domain controller) and basically holds the user data. | ||
+ | |||
+ | The closest analogue to real life, would be the telephone directory. Another generalised explanation of what an LDAP server does is that it is a database (which it basically is, but it is not relational) which is optimised for accessing the data and not writing them. | ||
− | {{ | + | Commands relate to OpenLDAP that begin with {{ic|ldap}} (like {{ic|ldapsearch}}) are client-side utilities while commands that begin with {{ic|slap}} (like {{ic|slapcat}}) are server-side. |
OpenLDAP, LDAP & Directory services are an enormous topic. Configuration is therefore complex. This page is a starting point for a basic OpenLDAP installation and a sanity check. | OpenLDAP, LDAP & Directory services are an enormous topic. Configuration is therefore complex. This page is a starting point for a basic OpenLDAP installation and a sanity check. | ||
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{{Note|If you already have an OpenLDAP database on your machine, remove it by deleting everything inside {{ic|/var/lib/openldap/openldap-data/}}.}} | {{Note|If you already have an OpenLDAP database on your machine, remove it by deleting everything inside {{ic|/var/lib/openldap/openldap-data/}}.}} | ||
− | + | The server configuration file is located at {{ic|/etc/openldap/slapd.conf}}. | |
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Edit the suffix and rootdn. The suffix typically is your domain name but it does not have to be. It depends on how you use your directory. We will use ''example'' for the domain name, and ''com'' for the tld. The rootdn is your LDAP administrator's name (we'll use ''root'' here). | Edit the suffix and rootdn. The suffix typically is your domain name but it does not have to be. It depends on how you use your directory. We will use ''example'' for the domain name, and ''com'' for the tld. The rootdn is your LDAP administrator's name (we'll use ''root'' here). | ||
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}} | }} | ||
− | {{ | + | Now prepare the database directory. You will need to copy the default config file and set the proper ownership: |
+ | # cp /etc/openldap/DB_CONFIG.example /var/lib/openldap/openldap-data/DB_CONFIG | ||
+ | # chown ldap:ldap /var/lib/openldap/openldap-data/DB_CONFIG | ||
+ | |||
+ | Now prepare the run directory: | ||
+ | # mkdir /run/openldap | ||
+ | # chown ldap:ldap /run/openldap | ||
+ | |||
+ | Finally you can start the slapd daemon with {{ic|slapd.service}} [[systemd#Using units|using systemd]]. | ||
+ | |||
+ | If you want to use SSL, see [[#OpenLDAP over TLS]]. | ||
+ | |||
+ | {{note|Index the directory after you populate it. You should stop slapd before doing this. | ||
# slapindex | # slapindex | ||
# chown ldap:ldap /var/lib/openldap/openldap-data/* | # chown ldap:ldap /var/lib/openldap/openldap-data/* | ||
}} | }} | ||
− | + | === The client === | |
− | + | {{Note|Keep in mind that your apps that require LDAP auth use it, so if something goes wrong with LDAP, do not waste your time with the app, start debugging the client instead.}} | |
− | |||
− | |||
− | |||
− | + | The client config file is located at {{ic|/etc/openldap/ldap.conf}}. | |
− | The client is | ||
− | + | It is quite simple: you'll only have to alter {{ic|BASE}} to reflect the suffix of the server, and {{ic|URI}} to reflect the address of the server. | |
− | It is | ||
If you decide to use SSL: | If you decide to use SSL: | ||
− | * The protocol (ldap or ldaps) in the URI entry has to conform with the slapd configuration | + | * The protocol (ldap or ldaps) in the {{ic|URI}} entry has to conform with the slapd configuration |
− | * If you decide to use self-signed certificates, | + | * If you decide to use self-signed certificates, add a {{ic|TLS_REQCERT allow}} entry |
=== Test your new OpenLDAP installation === | === Test your new OpenLDAP installation === | ||
This is easy, just run the command below: | This is easy, just run the command below: | ||
− | ldapsearch -x | + | $ ldapsearch -x '(objectclass=*)' |
− | Or | + | Or authenticating as the rootdn (replacing {{ic|-x}} by {{ic|-D <user> -W}}), using the example configuration we had above: |
− | ldapsearch | + | $ ldapsearch -D "cn=root,dc=example,dc=com" -W '(objectclass=*)' |
Now you should see some information about your database. | Now you should see some information about your database. | ||
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{{Note|[http://web.archive.org/web/20130211222328/http://www.openldap.org/pub/ksoper/OpenLDAP_TLS.html#4.0 upstream documentation] is much more useful/complete than this section}} | {{Note|[http://web.archive.org/web/20130211222328/http://www.openldap.org/pub/ksoper/OpenLDAP_TLS.html#4.0 upstream documentation] is much more useful/complete than this section}} | ||
− | If you access the | + | If you access the OpenLDAP server over the network and especially if you have sensitive data stored on the server you run the risk of someone sniffing your data which is sent clear-text. The next part will guide you on how to setup an SSL connection between the LDAP server and the client so the data will be sent encrypted. |
In order to use TLS, we must first create a certificate. You can have a certificate signed, or create your own Certificate Authority (CA), but for our purposed, a self-signed certificate will suffice. | In order to use TLS, we must first create a certificate. You can have a certificate signed, or create your own Certificate Authority (CA), but for our purposed, a self-signed certificate will suffice. | ||
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==== Create a self-signed certificate ==== | ==== Create a self-signed certificate ==== | ||
To create a ''self-signed'' certificate, type the following: | To create a ''self-signed'' certificate, type the following: | ||
− | + | $ openssl req -new -x509 -nodes -out slapdcert.pem -keyout slapdkey.pem -days 365 | |
You will be prompted for information about your LDAP server. Much of the information can be left blank. The most important information is the common name. This must be set to the DNS name of your LDAP server. If your LDAP server's IP address resolves to example.org but its server certificate shows a CN of bad.example.org, LDAP clients will reject the certificate and will be unable to negotiate TLS connections (apparently the results are wholly unpredictable). | You will be prompted for information about your LDAP server. Much of the information can be left blank. The most important information is the common name. This must be set to the DNS name of your LDAP server. If your LDAP server's IP address resolves to example.org but its server certificate shows a CN of bad.example.org, LDAP clients will reject the certificate and will be unable to negotiate TLS connections (apparently the results are wholly unpredictable). | ||
Now that the certificate files have been created copy them to {{ic|/etc/openldap/ssl/}} (if this directory doesn't exist create it) and secure them. | Now that the certificate files have been created copy them to {{ic|/etc/openldap/ssl/}} (if this directory doesn't exist create it) and secure them. | ||
− | + | {{ic|slapdcert.pem}} must be world readable because it contains the public key. {{ic|slapdkey.pem}} on the other hand should only be readable for the ldap user for security reasons: | |
− | + | # cp slapdcert.pem slapdkey.pem /etc/openldap/ssl/ | |
− | cp slapdcert.pem slapdkey.pem /etc/openldap/ssl/ | + | # chmod 400 slapdkey.pem |
− | + | # chmod 444 slapdcert.pem | |
− | chmod 400 slapdkey.pem | + | # chown ldap slapdkey.pem |
− | chmod 444 slapdcert.pem | ||
− | |||
==== Configure slapd for SSL ==== | ==== Configure slapd for SSL ==== | ||
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==== Start slapd with SSL ==== | ==== Start slapd with SSL ==== | ||
− | + | You will have to edit {{ic|slapd.service}} to change to protocol slapd listens on. | |
− | {{ | ||
− | |||
− | |||
+ | First, disable {{ic|slapd.service}} if it's enabled. | ||
+ | Then, copy the stock service to {{ic|/etc/systemd/system/}}: | ||
+ | # cp /usr/lib/systemd/system/slapd.service /etc/systemd/system/ | ||
− | + | Edit it, and add {{ic|-h "ldaps:///"}} to {{ic|ExecStart}}. It should look like this: | |
+ | {{hc|/etc/systemd/system/slapd.service|<nowiki> | ||
+ | ExecStart=/usr/bin/slapd -u ldap -g ldap -h "ldaps:///"</nowiki>}} | ||
− | + | Then reenable and start it: | |
+ | # systemctl daemon-reload | ||
+ | # systemctl enable slapd.service | ||
+ | # systemctl restart slapd.service | ||
− | + | Localhost connections don't need to use SSL so you could replace {{ic|"ldaps:///"}} by {{ic|"ldap://127.0.0.1 ldaps:///"}}. | |
+ | |||
+ | {{Note|If you created a self-signed certificate above be sure to add {{ic|TLS_REQCERT allow}} to {{ic|/etc/openldap/ldap.conf}} or you won't be able connect to the server.}} | ||
== Next Steps == | == Next Steps == | ||
− | You now have a basic | + | You now have a basic LDAP installation. The next step is to design your directory. The design is heavily dependent on what you are using it for. If you are new to LDAP, consider starting with a directory design recommended by the specific client services that will use the directory (PAM, [[Postfix]], etc). |
A directory for system authentication is the [[LDAP Authentication]] article. | A directory for system authentication is the [[LDAP Authentication]] article. | ||
+ | |||
+ | A nice web frontend is [[phpLDAPadmin]]. | ||
== Troubleshooting == | == Troubleshooting == | ||
Line 151: | Line 159: | ||
== See Also == | == See Also == | ||
− | * http://www.openldap.org/doc/admin24/ | + | * [http://www.openldap.org/doc/admin24/ Official OpenLDAP Software 2.4 Administrator's Guide] |
* [[phpLDAPadmin]] is a web interface tool in the style of phpMyAdmin. | * [[phpLDAPadmin]] is a web interface tool in the style of phpMyAdmin. | ||
− | * {{AUR|apachedirectorystudio2}} from the [[Arch User Repository]] is an Eclipse-based LDAP viewer. Works perfect | + | * [[LDAP Authentication]] |
+ | * {{AUR|apachedirectorystudio2}} from the [[Arch User Repository]] is an Eclipse-based LDAP viewer. Works perfect with OpenLDAP installations. |
Revision as of 01:16, 6 November 2013
OpenLDAP is an open-source implementation of the LDAP protocol. It is mainly used as an address book (for e.g. email clients) or authentication backend to various services (the most famous one being Samba, which is used to emulate a domain controller) and basically holds the user data.
The closest analogue to real life, would be the telephone directory. Another generalised explanation of what an LDAP server does is that it is a database (which it basically is, but it is not relational) which is optimised for accessing the data and not writing them.
Commands relate to OpenLDAP that begin with ldap
(like ldapsearch
) are client-side utilities while commands that begin with slap
(like slapcat
) are server-side.
OpenLDAP, LDAP & Directory services are an enormous topic. Configuration is therefore complex. This page is a starting point for a basic OpenLDAP installation and a sanity check.
If you are totally new to those concepts, this is an good introduction that is easy to understand and that will get you started, even if you are new to everything LDAP.
Contents
Installation
OpenLDAP contains both a LDAP server and client. Install it with the package openldap, available in the official repositories.
Configuration
The server
/var/lib/openldap/openldap-data/
.The server configuration file is located at /etc/openldap/slapd.conf
.
Edit the suffix and rootdn. The suffix typically is your domain name but it does not have to be. It depends on how you use your directory. We will use example for the domain name, and com for the tld. The rootdn is your LDAP administrator's name (we'll use root here).
suffix "dc=example,dc=com" rootdn "cn=root,dc=example,dc=com"
Now we delete the default root password and create a strong one:
# sed -i "/rootpw/ d" slapd.conf #find the line with rootpw and delete it # echo "rootpw $(slappasswd)" >> slapd.conf #add a line which includes the hashed password output from slappasswd
You will likely want to add some typically used schemas to the top of slapd.conf
:
include /etc/openldap/schema/cosine.schema include /etc/openldap/schema/inetorgperson.schema include /etc/openldap/schema/nis.schema
You will likely want to add some typically used indexes to the bottom of slapd.conf
:
index uid pres,eq index mail pres,sub,eq index cn pres,sub,eq index sn pres,sub,eq index dc eq
Now prepare the database directory. You will need to copy the default config file and set the proper ownership:
# cp /etc/openldap/DB_CONFIG.example /var/lib/openldap/openldap-data/DB_CONFIG # chown ldap:ldap /var/lib/openldap/openldap-data/DB_CONFIG
Now prepare the run directory:
# mkdir /run/openldap # chown ldap:ldap /run/openldap
Finally you can start the slapd daemon with slapd.service
using systemd.
If you want to use SSL, see #OpenLDAP over TLS.
# slapindex # chown ldap:ldap /var/lib/openldap/openldap-data/*
The client
The client config file is located at /etc/openldap/ldap.conf
.
It is quite simple: you'll only have to alter BASE
to reflect the suffix of the server, and URI
to reflect the address of the server.
If you decide to use SSL:
- The protocol (ldap or ldaps) in the
URI
entry has to conform with the slapd configuration - If you decide to use self-signed certificates, add a
TLS_REQCERT allow
entry
Test your new OpenLDAP installation
This is easy, just run the command below:
$ ldapsearch -x '(objectclass=*)'
Or authenticating as the rootdn (replacing -x
by -D <user> -W
), using the example configuration we had above:
$ ldapsearch -D "cn=root,dc=example,dc=com" -W '(objectclass=*)'
Now you should see some information about your database.
OpenLDAP over TLS
If you access the OpenLDAP server over the network and especially if you have sensitive data stored on the server you run the risk of someone sniffing your data which is sent clear-text. The next part will guide you on how to setup an SSL connection between the LDAP server and the client so the data will be sent encrypted.
In order to use TLS, we must first create a certificate. You can have a certificate signed, or create your own Certificate Authority (CA), but for our purposed, a self-signed certificate will suffice.
Create a self-signed certificate
To create a self-signed certificate, type the following:
$ openssl req -new -x509 -nodes -out slapdcert.pem -keyout slapdkey.pem -days 365
You will be prompted for information about your LDAP server. Much of the information can be left blank. The most important information is the common name. This must be set to the DNS name of your LDAP server. If your LDAP server's IP address resolves to example.org but its server certificate shows a CN of bad.example.org, LDAP clients will reject the certificate and will be unable to negotiate TLS connections (apparently the results are wholly unpredictable).
Now that the certificate files have been created copy them to /etc/openldap/ssl/
(if this directory doesn't exist create it) and secure them.
slapdcert.pem
must be world readable because it contains the public key. slapdkey.pem
on the other hand should only be readable for the ldap user for security reasons:
# cp slapdcert.pem slapdkey.pem /etc/openldap/ssl/ # chmod 400 slapdkey.pem # chmod 444 slapdcert.pem # chown ldap slapdkey.pem
Configure slapd for SSL
Edit the daemon configuration file (/etc/openldap/slapd.conf
) to tell LDAP where the certificate files reside by adding the following lines:
# Certificate/SSL Section TLSCipherSuite HIGH:MEDIUM:+SSLv2 TLSCertificateFile /etc/openldap/ssl/slapdcert.pem TLSCertificateKeyFile /etc/openldap/ssl/slapdkey.pem
The TLSCipherSuite specifies a list of OpenSSL ciphers from which slapd will choose when negotiating TLS connections, in decreasing order of preference. In addition to those specific ciphers, you can use any of the wildcards supported by OpenSSL. NOTE: HIGH, MEDIUM, and +SSLv2 are all wildcards.
openssl ciphers -v ALL
Start slapd with SSL
You will have to edit slapd.service
to change to protocol slapd listens on.
First, disable slapd.service
if it's enabled.
Then, copy the stock service to /etc/systemd/system/
:
# cp /usr/lib/systemd/system/slapd.service /etc/systemd/system/
Edit it, and add -h "ldaps:///"
to ExecStart
. It should look like this:
/etc/systemd/system/slapd.service
ExecStart=/usr/bin/slapd -u ldap -g ldap -h "ldaps:///"
Then reenable and start it:
# systemctl daemon-reload # systemctl enable slapd.service # systemctl restart slapd.service
Localhost connections don't need to use SSL so you could replace "ldaps:///"
by "ldap://127.0.0.1 ldaps:///"
.
TLS_REQCERT allow
to /etc/openldap/ldap.conf
or you won't be able connect to the server.Next Steps
You now have a basic LDAP installation. The next step is to design your directory. The design is heavily dependent on what you are using it for. If you are new to LDAP, consider starting with a directory design recommended by the specific client services that will use the directory (PAM, Postfix, etc).
A directory for system authentication is the LDAP Authentication article.
A nice web frontend is phpLDAPadmin.
Troubleshooting
If you notice that slapd seems to start but then stops, you may have a permission issue with the ldap datadir. Try running:
# chown ldap:ldap /var/lib/openldap/openldap-data/*
to allow slapd write access to its data directory as the user "ldap"
See Also
- Official OpenLDAP Software 2.4 Administrator's Guide
- phpLDAPadmin is a web interface tool in the style of phpMyAdmin.
- LDAP Authentication
- apachedirectorystudio2AUR from the Arch User Repository is an Eclipse-based LDAP viewer. Works perfect with OpenLDAP installations.