LDAP Alpine

The Lightweight Directory Access Protocol (LDAP) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network.

This image is based on Alpine Linux and OpenLDAP.

Customisation

Override the following environment variables when running the docker container to customise LDAP:

VARIABLE	DESCRIPTION	DEFAULT
ORGANISATION_NAME	Organisation name	Example Ltd
SUFFIX	Organisation distinguished name	dc=example,dc=com
ROOT_USER	Root username	admin
ROOT_PW	Root password	password
USER_UID	Initial user's uid	pgarrett
USER_GIVEN_NAME	Initial user's given name	Phill
USER_SURNAME	Initial user's surname	Garrett
USER_EMAIL	Initial user's email	pgarrett@example.com
USER_PW	Initial user's password	password
ACCESS_CONTROL	Global access control	access to * by * read
LOG_LEVEL	LDAP logging level, see below for valid values.	stats

For example:

docker run -t -p 389:389 \
  -e ORGANISATION_NAME="Beispiel gmbh" \
  -e SUFFIX="dc=beispiel,dc=de" \
  -e ROOT_PW="geheimnis" \
  pgarrett/ldap-alpine

Search for user:

ldapsearch -x -b "dc=beispiel,dc=de" "uid=pgarrett"

Logging Levels

NAME	DESCRIPTION
any	enable all debugging (warning! lots of messages will be output)
trace	trace function calls
packets	debug packet handling
args	heavy trace debugging
conns	connection management
BER	print out packets sent and received
filter	search filter processing
config	configuration processing
ACL	access control list processing
stats	stats log connections/operations/results
stats2	stats log entries sent
shell	print communication with shell backends
parse	print entry parsing debugging
sync	syncrepl consumer processing
none	only messages that get logged whatever log level is set

Custom ldif files

*.ldif files can be used to add lots of people to the organisation on startup.

Copy ldif files to /ldif and the container will execute them. This can be done either by extending this Dockerfile with your own:

FROM pgarrett/ldap-alpine
COPY my-users.ldif /ldif/

Or by mounting your scripts directory into the container:

docker run -t -p 389:389 -v /my-ldif:/ldif pgarrett/ldap-alpine

Persist data

The container uses a standard mdb backend. To persist this database outside the container mount /var/lib/openldap/openldap-data. For example:

docker run -t -p 389:389 -v /my-backup:/var/lib/openldap/openldap-data pgarrett/ldap-alpine

Transport Layer Security

The container can be started using the encrypted LDAPS protocol. You must provide all three TLS environment variables.

VARIABLE	DESCRIPTION	EXAMPLE
CA_FILE	PEM-format file containing certificates for the CA's that slapd will trust	/etc/ssl/certs/ca.pem
KEY_FILE	The slapd server private key	/etc/ssl/certs/public.key
CERT_FILE	The slapd server certificate	/etc/ssl/certs/public.crt
TLS_VERIFY_CLIENT	Slapd option for client certificate verification	try, never, demand

Note these variables inform the entrypoint script (executed on startup) where to find the SSL certificates inside the container. So the certificates must also be mounted at runtime too, for example:

docker run -t -p 389:389 \
  -v /my-certs:/etc/ssl/certs \
  -e CA_FILE /etc/ssl/certs/ca.pem \
  -e KEY_FILE /etc/ssl/certs/public.key \
  -e CERT_FILE /etc/ssl/certs/public.crt \
  pgarrett/ldap-alpine

Where /my-certs on the host contains the three certificate files ca.pem, public.key and public.crt.

To disable client certificates set TLS_VERIFY_CLIENT to never or try.

Access Control

Global access to your directory can be configured via the ACCESS_CONTROL environment variable.

The default policy allows anyone and everyone to read anything but restricts updates to rootdn.

access to * by * read

Note rootdn can always read and write everything!

You can find detailed documentation on access control here https://www.openldap.org/doc/admin24/access-control.html

This following access control allows the user to modify their entry, allows anonymous to authenticate against these entries, and allows all others to read these entries:

docker run -t -p 389:389 \
  -e ACCESS_CONTROL="access to * by self write by anonymous auth by users read" \
  pgarrett/ldap-alpine

Now ldapsearch -x -b "dc=example,dc=com" "uid=pgarret" will return no results.

In order to search you will need to authenticate (bind) first:

ldapsearch -D "uid=pgarrett,ou=Users,dc=example,dc=com" -w password -b "dc=example,dc=com" "uid=pgarrett"