Introduction to OpenLDAP
The OpenLDAP package provides an
open source implementation of the Lightweight Directory Access
Protocol.
![[Note]](../images/note.png)
Note
Development versions of BLFS may not build or run some packages
properly if LFS or dependencies have been updated since the most
recent stable versions of the books.
Package Information
Additional Downloads
OpenLDAP Dependencies
Recommended
Cyrus SASL-2.1.28
Optional
GnuTLS-3.8.8, unixODBC-2.3.12, MariaDB-11.4.4 or
PostgreSQL-17.1 or MySQL, OpenSLP, WiredTiger,
and Berkeley
DB (deprecated) (for slapd, also deprecated)
Installation of OpenLDAP
Note
If you only need to install the client side ldap* binaries, corresponding
man pages, libraries and header files (referred to as a
“client-only” install), issue these commands
instead of the following ones (no test suite available):
patch -Np1 -i ../openldap-2.6.8-consolidated-1.patch &&
autoconf &&
./configure --prefix=/usr \
--sysconfdir=/etc \
--disable-static \
--enable-dynamic \
--disable-debug \
--disable-slapd &&
make depend &&
make
Then, as the root user:
make install
There should be a dedicated user and group to take control of the
slapd daemon after it
is started. Issue the following commands as the root user:
groupadd -g 83 ldap &&
useradd -c "OpenLDAP Daemon Owner" \
-d /var/lib/openldap -u 83 \
-g ldap -s /bin/false ldap
Install OpenLDAP by running the
following commands:
patch -Np1 -i ../openldap-2.6.8-consolidated-1.patch &&
autoconf &&
./configure --prefix=/usr \
--sysconfdir=/etc \
--localstatedir=/var \
--libexecdir=/usr/lib \
--disable-static \
--disable-debug \
--with-tls=openssl \
--with-cyrus-sasl \
--without-systemd \
--enable-dynamic \
--enable-crypt \
--enable-spasswd \
--enable-slapd \
--enable-modules \
--enable-rlookups \
--enable-backends=mod \
--disable-sql \
--disable-wt \
--enable-overlays=mod &&
make depend &&
make
The tests are fragile, and errors may cause the tests to abort
prior to finishing. Some errors may happen due to timing problems.
The tests take around an hour, and the time is CPU independent due
to delays in the tests. On most systems, the tests will run up to
the test065-proxyauth for mdb test.
To test the results, issue: make
test.
Now, as the root user:
make install &&
sed -e "s/\.la/.so/" -i /etc/openldap/slapd.{conf,ldif}{,.default} &&
install -v -dm700 -o ldap -g ldap /var/lib/openldap &&
install -v -dm700 -o ldap -g ldap /etc/openldap/slapd.d &&
chmod -v 640 /etc/openldap/slapd.{conf,ldif} &&
chown -v root:ldap /etc/openldap/slapd.{conf,ldif} &&
install -v -dm755 /usr/share/doc/openldap-2.6.8 &&
cp -vfr doc/{drafts,rfc,guide} \
/usr/share/doc/openldap-2.6.8
Command Explanations
--disable-static: This
switch prevents installation of static versions of the libraries.
--disable-debug: This
switch disables the debugging code in OpenLDAP.
--enable-dynamic: This
switch forces the OpenLDAP
libraries to be dynamically linked to the executable programs.
--enable-crypt: This switch
enables using crypt(3) passwords.
--enable-spasswd: This
switch enables SASL password
verification.
--enable-modules: This
switch enables dynamic module support.
--enable-rlookups: This
switch enables reverse lookups of client hostnames.
--enable-backends: This
switch enables all available backends.
--enable-overlays: This
switch enables all available overlays.
--disable-sql: This switch
explicitly disables the SQL backend. Omit this switch if a SQL
server is installed and you are going to use a SQL backend.
--disable-wt: This switch
explicitly disables the WiredTiger backend. Omit this switch if
WiredTiger is installed and you are going to use a WiredTiger
backend.
--libexecdir=/usr/lib: This
switch controls where the /usr/lib/openldap directory is installed.
Everything in that directory is a library, so it belongs under
/usr/lib instead of /usr/libexec.
--enable-slp: This switch enables SLPv2
support. Use it if you have installed OpenSLP.
--disable-versioning: This switch
disables symbol versioning in the OpenLDAP libraries. The default is to have
symbol versioning. Note that if you have built applications using
this package with symbol versioning, and remove the symbols, the
applications may fail to run.
Note
You can run ./configure
--help to see if there are other switch you can
pass to the configure command to enable
other options or dependency packages.
install ...,
chown ..., and
chmod ...: Having
slapd configuration files and ldap databases in /var/lib/openldap
readable by anyone is a SECURITY ISSUE, especially since a file
stores the admin password in PLAIN TEXT. That's why mode 640 and
root:ldap ownership were used. The owner is root, so only root can
modify the file, and group is ldap, so that the group which owns
slapd daemon could read but not modify the file in case of a
security breach.
Configuring OpenLDAP
Config Files
-
For LDAP client: /etc/openldap/ldap.conf and ~/.ldaprc
-
For LDAP server, two configuration mechanisms are used: a
legacy /etc/openldap/slapd.conf configuration
file and the recommended slapd-config system, using an
LDIF database stored in /etc/openldap/slapd.d.
Configuration Information
Configuring the slapd servers can be complex.
Securing the LDAP directory, especially if you are storing
non-public data such as password databases, can also be a
challenging task. In order to set up OpenLDAP, you'll need to modify either the
/etc/openldap/slapd.conf file (old
method), or the /etc/openldap/slapd.ldif file and then use
ldapadd to create
the LDAP configuration database in /etc/openldap/slapd.d (recommended by the
OpenLDAP documentation).
![[Warning]](../images/warning.png)
Warning
The instructions above install an empty LDAP structure and a
default /etc/openldap/slapd.conf
file, which are suitable for testing the build and other
packages using LDAP. Do not use them on a production server.
Resources to assist you with topics such as choosing a directory
configuration, backend and database definitions, access control
settings, running as a user other than root and setting a chroot environment include:
Boot Script
To automate the startup of the LDAP server at system bootup,
install the /etc/rc.d/init.d/slapd init script
included in the blfs-bootscripts-20240913 package using
the following command:
make install-slapd
Note
You'll need to modify /etc/sysconfig/slapd to include the
parameters needed for your specific configuration. See the
slapd man page
for parameter information.
Testing the Configuration
Start the LDAP server using the init
script:
/etc/rc.d/init.d/slapd start
Verify access to the LDAP server with the following command:
ldapsearch -x -b '' -s base '(objectclass=*)' namingContexts
The expected result is:
# extended LDIF
#
# LDAPv3
# base <> with scope baseObject
# filter: (objectclass=*)
# requesting: namingContexts
#
#
dn:
namingContexts: dc=my-domain,dc=com
# search result
search: 2
result: 0 Success
# numResponses: 2
# numEntries: 1