Difference between revisions of "OpenLDAP"
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[[Category:Networking]] | [[Category:Networking]] | ||
[[ru:openLDAP]] | [[ru:openLDAP]] | ||
+ | {{Related articles start}} | ||
+ | {{Related|LDAP Authentication}} | ||
+ | {{Related|LDAP Hosts}} | ||
+ | {{Related articles end}} | ||
− | + | OpenLDAP is an open-source implementation of the LDAP protocol. An LDAP server basically is a non-relational database which is optimised for accessing, but not writing, data. It is mainly used as an address book (for e.g. email clients) or authentication backend to various services (such as Samba, where it is used to emulate a domain controller, or [[LDAP Authentication|Linux system authentication]], where it replaces {{ic|/etc/passwd}}) and basically holds the user data. | |
− | OpenLDAP, | + | Commands related 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. |
− | If you are totally new to those concepts, [http://www.brennan.id.au/20-Shared_Address_Book_LDAP.html this] is an good introduction that is easy to understand and that will get you started, even if you are new to everything LDAP. | + | Directory services are an enormous topic. Configuration can therefore be complex. This page is a starting point for a basic OpenLDAP installation and a sanity check. If you are totally new to those concepts, [http://www.brennan.id.au/20-Shared_Address_Book_LDAP.html this] is an good introduction that is easy to understand and that will get you started, even if you are new to everything LDAP. |
== Installation == | == Installation == | ||
Line 18: | Line 22: | ||
{{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}}. | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
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). | ||
Line 38: | Line 31: | ||
Now we delete the default root password and create a strong one: | 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 | + | # sed -i "/rootpw/ d" /etc/openldap/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 | + | # echo "rootpw $(slappasswd)" >> /etc/openldap/slapd.conf #add a line which includes the hashed password output from slappasswd |
− | + | You will likely want to add some typically used [http://www.openldap.org/doc/admin24/schema.html schemas] to the top of {{ic|slapd.conf}}: | |
{{bc| | {{bc| | ||
include /etc/openldap/schema/cosine.schema | include /etc/openldap/schema/cosine.schema | ||
Line 48: | Line 41: | ||
}} | }} | ||
− | + | You will likely want to add some typically used [http://www.openldap.org/doc/admin24/tuning.html#Indexes indexes] to the bottom of {{ic|slapd.conf}}: | |
{{bc| | {{bc| | ||
index uid pres,eq | index uid pres,eq | ||
Line 57: | Line 50: | ||
}} | }} | ||
− | + | 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 ({{bug|38408}}): | ||
+ | # systemd-tmpfiles --create slapd.conf | ||
+ | |||
+ | {{Note|With OpenLDAP 2.4 the configuration of {{ic|slapd.config}} is deprecated. From this version on all configuration settings are stored in {{ic|/etc/openldap/slapd.d/}}.}} | ||
− | + | To store the recent changes in {{ic|slapd.conf}} to the new {{ic|slapd-config}} configuration settings, we have to delete the old configuration files first: | |
− | + | # rm -rf /etc/openldap/slapd.d/* | |
− | + | ||
− | + | Then we generate the new configuration with: | |
+ | |||
+ | # slapdtest -f /etc/openldap/slapd.conf -F /etc/openldap/slapd.d/ | ||
+ | |||
+ | This last command has to be run every time you change {{ic|slapd.conf}}. | ||
+ | |||
+ | Check if everything succeeded and finally start the slapd daemon with {{ic|slapd.service}} [[systemd#Using units|using systemd]]. | ||
+ | |||
+ | {{note|Index the directory after you populate it. You should stop slapd before doing this. | ||
+ | # slapindex | ||
+ | # chown ldap:ldap /var/lib/openldap/openldap-data/* | ||
+ | }} | ||
=== The client === | === The client === | ||
− | The client is | + | The client config file is located at {{ic|/etc/openldap/ldap.conf}}. |
− | + | 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, like: | |
− | + | ||
+ | {{hc|/etc/openldap/ldap.conf|2= | ||
+ | BASE dc=example,dc=com | ||
+ | URI ldap://localhost | ||
+ | }} | ||
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 | + | |
− | * If you decide to use self-signed certificates, | + | * 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, add a {{ic|TLS_REQCERT allow}} line to {{ic|ldap.conf}} | ||
=== 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. | ||
Line 88: | Line 104: | ||
{{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, you must have a certificate. For testing purposes, a ''self-signed'' certificate will suffice. To learn more about certificates, see [[OpenSSL]]. | ||
− | |||
{{Warning|OpenLDAP cannot use a certificate that has a password associated to it.}} | {{Warning|OpenLDAP cannot use a certificate that has a password associated to it.}} | ||
==== 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/}} ( | + | Now that the certificate files have been created copy them to {{ic|/etc/openldap/ssl/}} (create this directory if it doesn't exist) 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: | |
− | + | # mv slapdcert.pem slapdkey.pem /etc/openldap/ssl/ | |
− | + | # chmod -R 744 /etc/openldap/ssl/ | |
− | + | # chmod 400 /etc/openldap/ssl/slapdkey.pem | |
− | chmod 400 slapdkey.pem | + | # chmod 444 /etc/openldap/ssl/slapdcert.pem |
− | chmod 444 slapdcert.pem | + | # chown ldap /etc/openldap/ssl/slapdkey.pem |
− | }} | + | |
+ | The {{ic|/etc/openldap/slapd.d}} folder and it's files should be owned by {{ic|ldap}} user and group: | ||
+ | # chown -R ldap:ldap /etc/openldap/slapd.d/ | ||
==== Configure slapd for SSL ==== | ==== Configure slapd for SSL ==== | ||
Line 112: | Line 131: | ||
{{bc| | {{bc| | ||
# Certificate/SSL Section | # Certificate/SSL Section | ||
− | TLSCipherSuite HIGH:MEDIUM: | + | TLSCipherSuite HIGH:MEDIUM:-SSLv2 |
TLSCertificateFile /etc/openldap/ssl/slapdcert.pem | TLSCertificateFile /etc/openldap/ssl/slapdcert.pem | ||
TLSCertificateKeyFile /etc/openldap/ssl/slapdkey.pem | TLSCertificateKeyFile /etc/openldap/ssl/slapdkey.pem | ||
Line 122: | Line 141: | ||
==== 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 change {{ic|ExecStart}} to: | ||
+ | {{hc|/etc/systemd/system/slapd.service|<nowiki> | ||
+ | ExecStart=/usr/bin/slapd -u ldap -g ldap -h "ldaps:///"</nowiki>}} | ||
− | ' | + | Localhost connections don't need to use SSL. So, if you want to access the server locally you should change the {{ic|ExecStart}} line to: |
+ | ExecStart=/usr/bin/slapd -u ldap -g ldap -h "ldap://127.0.0.1 ldaps:///" | ||
− | + | Then reenable and start it: | |
+ | # systemctl daemon-reload | ||
+ | # systemctl restart slapd.service | ||
− | + | If {{ic|slapd}} started successfully you can enable it with: | |
+ | # systemctl enable slapd.service | ||
+ | |||
+ | {{Note|If you created a self-signed certificate above, be sure to add {{ic|TLS_REQCERT allow}} to {{ic|/etc/openldap/ldap.conf}} on the client, or it 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 148: | Line 179: | ||
== 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 14:11, 13 January 2014
OpenLDAP is an open-source implementation of the LDAP protocol. An LDAP server basically is a non-relational database which is optimised for accessing, but not writing, data. It is mainly used as an address book (for e.g. email clients) or authentication backend to various services (such as Samba, where it is used to emulate a domain controller, or Linux system authentication, where it replaces /etc/passwd
) and basically holds the user data.
Commands related to OpenLDAP that begin with ldap
(like ldapsearch
) are client-side utilities, while commands that begin with slap
(like slapcat
) are server-side.
Directory services are an enormous topic. Configuration can therefore be 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" /etc/openldap/slapd.conf #find the line with rootpw and delete it # echo "rootpw $(slappasswd)" >> /etc/openldap/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 (FS#38408):
# systemd-tmpfiles --create slapd.conf
slapd.config
is deprecated. From this version on all configuration settings are stored in /etc/openldap/slapd.d/
.To store the recent changes in slapd.conf
to the new slapd-config
configuration settings, we have to delete the old configuration files first:
# rm -rf /etc/openldap/slapd.d/*
Then we generate the new configuration with:
# slapdtest -f /etc/openldap/slapd.conf -F /etc/openldap/slapd.d/
This last command has to be run every time you change slapd.conf
.
Check if everything succeeded and finally start the slapd daemon with slapd.service
using systemd.
# 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, like:
/etc/openldap/ldap.conf
BASE dc=example,dc=com URI ldap://localhost
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
line toldap.conf
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, you must have a certificate. For testing purposes, a self-signed certificate will suffice. To learn more about certificates, see OpenSSL.
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/
(create this directory if it doesn't exist) 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:
# mv slapdcert.pem slapdkey.pem /etc/openldap/ssl/ # chmod -R 744 /etc/openldap/ssl/ # chmod 400 /etc/openldap/ssl/slapdkey.pem # chmod 444 /etc/openldap/ssl/slapdcert.pem # chown ldap /etc/openldap/ssl/slapdkey.pem
The /etc/openldap/slapd.d
folder and it's files should be owned by ldap
user and group:
# chown -R ldap:ldap /etc/openldap/slapd.d/
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 change ExecStart
to:
/etc/systemd/system/slapd.service
ExecStart=/usr/bin/slapd -u ldap -g ldap -h "ldaps:///"
Localhost connections don't need to use SSL. So, if you want to access the server locally you should change the ExecStart
line to:
ExecStart=/usr/bin/slapd -u ldap -g ldap -h "ldap://127.0.0.1 ldaps:///"
Then reenable and start it:
# systemctl daemon-reload # systemctl restart slapd.service
If slapd
started successfully you can enable it with:
# systemctl enable slapd.service
TLS_REQCERT allow
to /etc/openldap/ldap.conf
on the client, or it 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.