ckanext-ldap

A CKAN extension that provides LDAP authentication.

Overview

This plugin provides LDAP authentication for CKAN.

Features include:

Imports username, full name, email and description;
Can match against several LDAP fields (eg. username or full name);
Allows to have LDAP only authentication, or combine LDAP and basic CKAN authentication;
Can add LDAP users to a given organization automatically;
Works with Active Directory.

Installation

Path variables used below:

$INSTALL_FOLDER (i.e. where CKAN is installed), e.g. /usr/lib/ckan/default
$CONFIG_FILE, e.g. /etc/ckan/default/development.ini

Installing from PyPI

pip install ckanext-ldap

Installing from source

Clone the repository into the src folder:

cd $INSTALL_FOLDER/src
git clone https://github.com/NaturalHistoryMuseum/ckanext-ldap.git

Activate the virtual env:
```
. $INSTALL_FOLDER/bin/activate
```

Install via pip:

pip install $INSTALL_FOLDER/src/ckanext-ldap

Installing in editable mode

Installing from a pyproject.toml in editable mode (i.e. pip install -e) requires setuptools>=64; however, CKAN 2.9 requires setuptools==44.1.0. See our CKAN fork for a version of v2.9 that uses an updated setuptools if this functionality is something you need.

Post-install setup

Add 'ldap' to the list of plugins in your $CONFIG_FILE:
```
ckan.plugins = ... ldap
```

Configuration

These are the options that can be specified in your .ini config file.

LDAP configuration [REQUIRED]

Name	Description	Options
`ckanext.ldap.uri`	The URI of the LDAP server, of the form ldap://example.com. You can use the URI to specify TLS (use 'ldaps' protocol), and the port number (suffix ':port').	True/False
`ckanext.ldap.base_dn`	The base dn in which to perform the search. Example: 'ou=USERS,dc=example,dc=com'.
`ckanext.ldap.search.filter`	This is the search string that is sent to the LDAP server, in which '{login}' is replaced by the user name provided by the user. Example: 'sAMAccountName={login}'. The search performed here must return exactly 0 or 1 entry.
`ckanext.ldap.username`	The LDAP attribute that will be used as the CKAN username. This must be unique.
`ckanext.ldap.email`	The LDAP attribute to map to the user's email address. This must be unique.

Other options

Name	Description	Options	Default
`ckanext.ldap.ckan_fallback`	If true this will attempt to log in against the CKAN user database when no LDAP user exists.	True/False	False
`ckanext.ldap.prevent_edits`	If true, this will prevent LDAP users from editing their profile. Note that there is no problem in allowing users to change their details - even their user name can be changed. But you may prefer to keep things centralized in your LDAP server. Important: while this prevents the operation from happening, it won't actually remove the 'edit settings' button from the dashboard. You need to do this in your own template.	True/False	False
`ckanext.ldap.auth.dn`	DN to use if LDAP server requires authentication.
`ckanext.ldap.auth.password`	Password to use if LDAP server requires authentication.
`ckanext.ldap.auth.method`	Authentication method	SIMPLE, SASL
`ckanext.ldap.auth.mechanism`	SASL mechanism to use, if auth.method is set to SASL.
`ckanext.ldap.fullname`	The LDAP attribute to map to the user's full name.
`ckanext.ldap.about`	The LDAP attribute to map to the user's description.
`ckanext.ldap.organization.id`	If this is set, users that log in using LDAP will automatically get added to the given organization. Warning: Changing this parameter will only affect users that have not yet logged on. It will not modify the organization of users who have already logged on. Warning: The organization to which to add LDAP users must already exist; the first user logging in will not automatically create it and instead you will see a "500 Server Error" returned.
`ckanext.ldap.organization.role`	The role given to users added in the given organization ('admin', 'editor' or 'member'). Warning: Changing this parameter will only affect users that have not yet logged on. It will not modify the role of users who have already logged on. This is only used if `ckanext.ldap.organization.id` is set. There is currently no functionality for mapping LDAP groups to CKAN roles, so this just assigns the same role to every new LDAP user.	member, editor, admin	'member'
`ckanext.ldap.search.alt`	An alternative search string for the LDAP filter. If this is present and the search using `ckanext.ldap.search.filter` returns exactly 0 results, then a search using this filter will be performed. If this search returns exactly one result, then it will be accepted. You can use this for example in Active Directory to match against both username and fullname by setting `ckanext.ldap.search.filter` to 'sAMAccountName={login}' and `ckanext.ldap.search.alt` to 'name={login}'. The approach of using two separate filter strings (rather than one with an or statement) ensures that priority will always be given to the unique id match. `ckanext.ldap.search.alt` however can be used to match against more than one field. For example you could match against either the full name or the email address by setting `ckanext.ldap.search.alt` to '(\	(name={login})(mail={login}))'.
`ckanext.ldap.search.alt_msg`	A message that is output to the user when the search on `ckanext.ldap.search.filter` returns 0 results, and the search on `ckanext.ldap.search.alt` returns more than one result. Example: 'Please use your short account name instead'.
`ckanext.ldap.migrate`	If true this will change an existing CKAN user with the same username to an LDAP user. Otherwise, an exception `UserConflictError`is raised if LDAP-login with an already existing local CKAN username is attempted. This option provides a migration path from local CKAN authentication to LDAP authentication: Rename all users to their LDAP usernames and instruct them to login with their LDAP credentials. Migration then happens transparently.	True/False	False
`ckanext.ldap.debug_level`	python-ldap debug level. Security warning: it is strongly recommended to keep this parameter set to 0 (zero) on production systems, otherwise plaintext passwords will be logged by `python-ldap`	0-9	0
`ckanext.ldap.trace_level`	python-ldap trace level. Security warning: it is strongly recommended to keep this parameter set to 0 (zero) on production systems, otherwise plaintext passwords will be logged by `python-ldap`	0-9	0
`ckanext.ldap.allow_password_reset`	If true, allows LDAP users to reset their passwords, if false, disallows this functionality. Note that if this is true, the password that is reset is the CKAN user password, not the LDAP one. If set to false, the request to reset will be denied only if the user is an LDAP user, if not they will be allowed to reset regardless of the value of this option.	True/False	true
`ckanext.ldap.ignore_referrals`	If true, The plugin will ignore referral query results sent by the LDAP server. This might be necessary if your base_dn is at the domain level, but the LDAP server searches in multiple paths for the user, resulting in queries containing more than one result.	True/False	false

Usage

Example Test Configuration

To test that the extension is working correctly without having to set up an LDAP service yourself, you can try this config snippet:

ckanext.ldap.uri = ldap://ldap.forumsys.com:389
ckanext.ldap.base_dn = dc=example,dc=com
ckanext.ldap.search.filter = cn=*{login}*
ckanext.ldap.username = cn
ckanext.ldap.auth.dn = cn=read-only-admin,dc=example,dc=com
ckanext.ldap.email = mail
ckanext.ldap.auth.password = password
ckanext.ldap.auth.method = SIMPLE

See here for more information. Then just login with tesla or gauss for example with password as the password.

Commands

`ldap`

setup-org: create the organisation specified in ckanext.ldap.organization.id.
```
ckan -c $CONFIG_FILE ldap setup-org
```
initdb: ensure the tables needed by this extension exist.
```
ckan -c $CONFIG_FILE ldap initdb
```

Templates

This extension overrides templates/user/login.html and sets the form action to the LDAP login handler.

To use it elsewhere:

{% set ldap_action = h.get_login_action() %}
{% snippet "user/snippets/login_form.html", action=ldap_action, error_summary=error_summary %}

The helper function h.is_ldap_user() is also provided for templates.

Testing

There is a Docker compose configuration available in this repository to make it easier to run tests. The ckan image uses the Dockerfile in the docker/ folder.

To run the tests can be run against ckan 2.9.x and 2.10.x on Python3:

Build the required images:
```
docker compose build
```
Then run the tests. The root of the repository is mounted into the ckan container as a volume by the Docker compose configuration, so you should only need to rebuild the ckan image if you change the extension's dependencies.
```
# run tests against ckan 2.9.x
docker compose run latest

# run tests against ckan 2.10.x
docker compose run next
```