.. _authentication:

Authentication setup

====================

Users can be authenticated in different ways. By default, Kallithea

uses its internal user database. Alternative authentication

methods include LDAP, PAM, Crowd, and container-based authentication.

.. _ldap-setup:

LDAP Authentication

-------------------

Kallithea supports LDAP authentication. In order

to use LDAP, you have to install the python-ldap_ package. This package is

available via PyPI, so you can install it by running::

    pip install python-ldap

.. note:: ``python-ldap`` requires some libraries to be installed on

          your system, so before installing it check that you have at

          least the ``openldap`` and ``sasl`` libraries.

Choose *Admin > Authentication*, click the ``kallithea.lib.auth_modules.auth_ldap`` button

and then *Save*, to enable the LDAP plugin and configure its settings.

Here's a typical LDAP setup::

 Connection settings

 Enable LDAP          = checked

 Host                 = host.example.com

 Account              = <account>

 Password             = <password>

 Connection Security  = LDAPS

 Certificate Checks   = DEMAND

 Search settings

 Base DN              = CN=users,DC=host,DC=example,DC=org

 LDAP Filter          = (&(objectClass=user)(!(objectClass=computer)))

 LDAP Search Scope    = SUBTREE

 Attribute mappings

 Login Attribute      = uid

 First Name Attribute = firstName

 Last Name Attribute  = lastName

 Email Attribute      = mail

If your user groups are placed in an Organisation Unit (OU) structure, the Search Settings configuration differs::

 Search settings

 Base DN              = DC=host,DC=example,DC=org

 LDAP Filter          = (&(memberOf=CN=your user group,OU=subunit,OU=unit,DC=host,DC=example,DC=org)(objectClass=user))

 LDAP Search Scope    = SUBTREE

.. _enable_ldap:

Enable LDAP : required

    Whether to use LDAP for authenticating users.

.. _ldap_host:

Host : required

    LDAP server hostname or IP address. Can be also a comma separated

    list of servers to support LDAP fail-over.

.. _Port:

Port : optional

    Defaults to 389 for PLAIN un-encrypted LDAP and START_TLS.

    Defaults to 636 for LDAPS.

.. _ldap_account:

Account : optional

    Only required if the LDAP server does not allow anonymous browsing of

    records.  This should be a special account for record browsing.  This

    will require `LDAP Password`_ below.

.. _LDAP Password:

Password : optional

    Only required if the LDAP server does not allow anonymous browsing of

    records.

.. _Enable LDAPS:

Connection Security : required

    Defines the connection to LDAP server

    PLAIN

        Plain unencrypted LDAP connection.

        This will by default use `Port`_ 389.

    LDAPS

        Use secure LDAPS connections according to `Certificate

        Checks`_ configuration.

        This will by default use `Port`_ 636.

    START_TLS

        Use START TLS according to `Certificate Checks`_ configuration on an

        apparently "plain" LDAP connection.

        This will by default use `Port`_ 389.

.. _Certificate Checks:

Certificate Checks : optional

    How SSL certificates verification is handled -- this is only useful when

    `Enable LDAPS`_ is enabled.  Only DEMAND or HARD offer full SSL security

    with mandatory certificate validation, while the other options are

    susceptible to man-in-the-middle attacks.

    NEVER

        A serve certificate will never be requested or checked.

    ALLOW

        A server certificate is requested.  Failure to provide a

        certificate or providing a bad certificate will not terminate the

        session.

    TRY

        A server certificate is requested.  Failure to provide a

        certificate does not halt the session; providing a bad certificate

        halts the session.

    DEMAND

        A server certificate is requested and must be provided and

        authenticated for the session to proceed.

    HARD

        The same as DEMAND.

.. _Custom CA Certificates:

Custom CA Certificates : optional

    Directory used by OpenSSL to find CAs for validating the LDAP server certificate.

    Python 2.7.10 and later default to using the system certificate store, and

    this should thus not be necessary when using certificates signed by a CA

    trusted by the system.

    It can be set to something like `/etc/openldap/cacerts` on older systems or

    if using self-signed certificates.

.. _Base DN:

Base DN : required

    The Distinguished Name (DN) where searches for users will be performed.

    Searches can be controlled by `LDAP Filter`_ and `LDAP Search Scope`_.

.. _LDAP Filter:

LDAP Filter : optional

    A LDAP filter defined by RFC 2254.  This is more useful when `LDAP

    Search Scope`_ is set to SUBTREE.  The filter is useful for limiting

    which LDAP objects are identified as representing Users for

    authentication.  The filter is augmented by `Login Attribute`_ below.

    This can commonly be left blank.

.. _LDAP Search Scope:

LDAP Search Scope : required

    This limits how far LDAP will search for a matching object.

    BASE

        Only allows searching of `Base DN`_ and is usually not what you

        want.

    ONELEVEL

        Searches all entries under `Base DN`_, but not Base DN itself.

    SUBTREE

        Searches all entries below `Base DN`_, but not Base DN itself.

        When using SUBTREE `LDAP Filter`_ is useful to limit object

        location.

.. _Login Attribute:

Login Attribute : required

    The LDAP record attribute that will be matched as the USERNAME or

    ACCOUNT used to connect to Kallithea.  This will be added to `LDAP

    Filter`_ for locating the User object.  If `LDAP Filter`_ is specified as

    "LDAPFILTER", `Login Attribute`_ is specified as "uid" and the user has

    connected as "jsmith" then the `LDAP Filter`_ will be augmented as below

    ::

        (&(LDAPFILTER)(uid=jsmith))

.. _ldap_attr_firstname:

First Name Attribute : required

    The LDAP record attribute which represents the user's first name.

.. _ldap_attr_lastname:

Last Name Attribute : required

    The LDAP record attribute which represents the user's last name.

.. _ldap_attr_email:

Email Attribute : required

    The LDAP record attribute which represents the user's email address.

If all data are entered correctly, and python-ldap_ is properly installed

users should be granted access to Kallithea with LDAP accounts.  At this

time user information is copied from LDAP into the Kallithea user database.

This means that updates of an LDAP user object may not be reflected as a

user update in Kallithea.

If You have problems with LDAP access and believe You entered correct

information check out the Kallithea logs, any error messages sent from LDAP

will be saved there.

Active Directory

^^^^^^^^^^^^^^^^

Kallithea can use Microsoft Active Directory for user authentication.  This

is done through an LDAP or LDAPS connection to Active Directory.  The

following LDAP configuration settings are typical for using Active

Directory ::

 Base DN              = OU=SBSUsers,OU=Users,OU=MyBusiness,DC=v3sys,DC=local

 Login Attribute      = sAMAccountName

 First Name Attribute = givenName

 Last Name Attribute  = sn

 Email Attribute     = mail

All other LDAP settings will likely be site-specific and should be

appropriately configured.

Authentication by container or reverse-proxy

--------------------------------------------

Kallithea supports delegating the authentication

of users to its WSGI container, or to a reverse-proxy server through which all

clients access the application.

When these authentication methods are enabled in Kallithea, it uses the

username that the container/proxy (Apache or Nginx, etc.) provides and doesn't

perform the authentication itself. The authorization, however, is still done by

Kallithea according to its settings.

When a user logs in for the first time using these authentication methods,

a matching user account is created in Kallithea with default permissions. An

administrator can then modify it using Kallithea's admin interface.

It's also possible for an administrator to create accounts and configure their

permissions before the user logs in for the first time, using the :ref:`create-user` API.

Container-based authentication

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In a container-based authentication setup, Kallithea reads the user name from

the ``REMOTE_USER`` server variable provided by the WSGI container.

After setting up your container (see :ref:`apache_mod_wsgi`), you'll need

to configure it to require authentication on the location configured for

Kallithea.

Proxy pass-through authentication

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In a proxy pass-through authentication setup, Kallithea reads the user name

from the ``X-Forwarded-User`` request header, which should be configured to be

sent by the reverse-proxy server.

After setting up your proxy solution (see :ref:`apache_virtual_host_reverse_proxy`,

:ref:`apache_subdirectory` or :ref:`nginx_virtual_host`), you'll need to

configure the authentication and add the username in a request header named

``X-Forwarded-User``.

For example, the following config section for Apache sets a subdirectory in a

reverse-proxy setup with basic auth:

.. code-block:: apache

    <Location /someprefix>

      ProxyPass http://127.0.0.1:5000/someprefix

      ProxyPassReverse http://127.0.0.1:5000/someprefix

      SetEnvIf X-Url-Scheme https HTTPS=1

      AuthType Basic

      AuthName "Kallithea authentication"

      AuthUserFile /srv/kallithea/.htpasswd

      Require valid-user

      RequestHeader unset X-Forwarded-User

      RewriteEngine On

      RewriteCond %{LA-U:REMOTE_USER} (.+)

      RewriteRule .* - [E=RU:%1]

      RequestHeader set X-Forwarded-User %{RU}e

    </Location>

Setting metadata in container/reverse-proxy

"""""""""""""""""""""""""""""""""""""""""""

When a new user account is created on the first login, Kallithea has no information about

the user's email and full name. So you can set some additional request headers like in the

example below. In this example the user is authenticated via Kerberos and an Apache

mod_python fixup handler is used to get the user information from a LDAP server. But you

could set the request headers however you want.

.. code-block:: apache

    <Location /someprefix>

      ProxyPass http://127.0.0.1:5000/someprefix

      ProxyPassReverse http://127.0.0.1:5000/someprefix

      SetEnvIf X-Url-Scheme https HTTPS=1

      AuthName "Kerberos Login"

      AuthType Kerberos

      Krb5Keytab /etc/apache2/http.keytab

      KrbMethodK5Passwd off

      KrbVerifyKDC on

      Require valid-user

      PythonFixupHandler ldapmetadata

      RequestHeader set X_REMOTE_USER %{X_REMOTE_USER}e

      RequestHeader set X_REMOTE_EMAIL %{X_REMOTE_EMAIL}e

      RequestHeader set X_REMOTE_FIRSTNAME %{X_REMOTE_FIRSTNAME}e

      RequestHeader set X_REMOTE_LASTNAME %{X_REMOTE_LASTNAME}e

    </Location>

.. code-block:: python

    from mod_python import apache

    import ldap

    LDAP_SERVER = "ldaps://server.mydomain.com:636"

    LDAP_USER = ""

    LDAP_PASS = ""

    LDAP_ROOT = "dc=mydomain,dc=com"

    LDAP_FILTER = "sAMAccountName=%s"

    LDAP_ATTR_LIST = ['sAMAccountName','givenname','sn','mail']

    def fixuphandler(req):

        if req.user is None:

            # no user to search for

            return apache.OK

        else:

            try:

                if('\\' in req.user):

                    username = req.user.split('\\')[1]

                elif('@' in req.user):

                    username = req.user.split('@')[0]

                else:

                    username = req.user

                l = ldap.initialize(LDAP_SERVER)

                l.simple_bind_s(LDAP_USER, LDAP_PASS)

                r = l.search_s(LDAP_ROOT, ldap.SCOPE_SUBTREE, LDAP_FILTER % username, attrlist=LDAP_ATTR_LIST)

                req.subprocess_env['X_REMOTE_USER'] = username

                req.subprocess_env['X_REMOTE_EMAIL'] = r[0][1]['mail'][0].lower()

                req.subprocess_env['X_REMOTE_FIRSTNAME'] = "%s" % r[0][1]['givenname'][0]

                req.subprocess_env['X_REMOTE_LASTNAME'] = "%s" % r[0][1]['sn'][0]

            except Exception, e:

                apache.log_error("error getting data from ldap %s" % str(e), apache.APLOG_ERR)

            return apache.OK

.. note::

   If you enable proxy pass-through authentication, make sure your server is

   only accessible through the proxy. Otherwise, any client would be able to

   forge the authentication header and could effectively become authenticated

   using any account of their liking.

.. _python-ldap: http://www.python-ldap.org/

.. _overview:

=====================

Installation overview

=====================

Some overview and some details that can help understanding the options when

installing Kallithea.

Python environment

------------------

**Kallithea** is written entirely in Python_ and requires Python version

2.6 or higher. Python 3.x is currently not supported.

Given a Python installation, there are different ways of providing the

environment for running Python applications. Each of them pretty much

corresponds to a ``site-packages`` directory somewhere where packages can be

installed.

Kallithea itself can be run from source or be installed, but even when running

from source, there are some dependencies that must be installed in the Python

environment used for running Kallithea.

- Packages *could* be installed in Python's ``site-packages`` directory ... but

  that would require running pip_ as root and it would be hard to uninstall or

  upgrade and is probably not a good idea unless using a package manager.

- Packages could also be installed in ``~/.local`` ... but that is probably

  only a good idea if using a dedicated user per application or instance.

- Finally, it can be installed in a virtualenv_. That is a very lightweight

  "container" where each Kallithea instance can get its own dedicated and

  self-contained virtual environment.

We recommend using virtualenv for installing Kallithea.

Installation methods

--------------------

Kallithea must be installed on a server. Kallithea is installed in a Python

environment so it can use packages that are installed there and make itself

available for other packages.

Two different cases will pretty much cover the options for how it can be

installed.

- The Kallithea source repository can be cloned and used -- it is kept stable and

  can be used in production. The Kallithea maintainers use the development

  branch in production. The advantage of installation from source and regularly

  updating it is that you take advantage of the most recent improvements. Using

  it directly from a DVCS also means that it is easy to track local customizations.

  Running ``pip install -e .`` in the source will use pip to install the

  necessary dependencies in the Python environment and create a

  ``.../site-packages/Kallithea.egg-link`` file there that points at the Kallithea

  source.

- Kallithea can also be installed from ready-made packages using a package manager.

  The official released versions are available on PyPI_ and can be downloaded and

  installed with all dependencies using ``pip install kallithea``.

  With this method, Kallithea is installed in the Python environment as any

  other package, usually as a ``.../site-packages/Kallithea-X-py2.7.egg/``

  directory with Python files and everything else that is needed.

  (``pip install kallithea`` from a source tree will do pretty much the same

  but build the Kallithea package itself locally instead of downloading it.)

Web server

----------

Kallithea is (primarily) a WSGI_ application that must be run from a web

server that serves WSGI applications over HTTP.

Kallithea itself is not serving HTTP (or HTTPS); that is the web server's

responsibility. Kallithea does however need to know its own user facing URL

(protocol, address, port and path) for each HTTP request. Kallithea will

usually use its own HTML/cookie based authentication but can also be configured

to use web server authentication.

There are several web server options:

- Kallithea uses the Gearbox_ tool as command line interface. Gearbox provides

  ``gearbox serve`` as a convenient way to launch a Python WSGI / web server

  from the command line. That is perfect for development and evaluation.

  Actual use in production might have different requirements and need extra

  work to make it manageable as a scalable system service.

  Gearbox comes with its own built-in web server but Kallithea defaults to use

  Waitress_. Gunicorn_ is also an option. These web servers have different

  limited feature sets.

  The web server used by ``gearbox`` is configured in the ``.ini`` file passed

  to it. The entry point for the WSGI application is configured

  in ``setup.py`` as ``kallithea.config.middleware:make_app``.

- `Apache httpd`_ can serve WSGI applications directly using mod_wsgi_ and a

  simple Python file with the necessary configuration. This is a good option if

  Apache is an option.

- uWSGI_ is also a full web server with built-in WSGI module.

- IIS_ can also server WSGI applications directly using isapi-wsgi_.

- A `reverse HTTP proxy <https://en.wikipedia.org/wiki/Reverse_proxy>`_

  can be put in front of another web server which has WSGI support.

  Such a layered setup can be complex but might in some cases be the right

  option, for example to standardize on one internet-facing web server, to add

  encryption or special authentication or for other security reasons, to

  provide caching of static files, or to provide load balancing or fail-over.

  Nginx_, Varnish_ and HAProxy_ are often used for this purpose, often in front

  of a ``gearbox serve`` that somehow is wrapped as a service.

The best option depends on what you are familiar with and the requirements for

performance and stability. Also, keep in mind that Kallithea mainly is serving

dynamically generated pages from a relatively slow Python process. Kallithea is

also often used inside organizations with a limited amount of users and thus no

continuous hammering from the internet.

.. _Python: http://www.python.org/

.. _Gunicorn: http://gunicorn.org/

.. _Waitress: http://waitress.readthedocs.org/en/latest/

.. _virtualenv: http://pypi.python.org/pypi/virtualenv

.. _Gearbox: http://turbogears.readthedocs.io/en/latest/turbogears/gearbox.html

.. _PyPI: https://pypi.python.org/pypi

.. _Apache httpd: http://httpd.apache.org/

.. _mod_wsgi: https://code.google.com/p/modwsgi/

.. _isapi-wsgi: https://github.com/hexdump42/isapi-wsgi

.. _uWSGI: https://uwsgi-docs.readthedocs.org/en/latest/

.. _nginx: http://nginx.org/en/

.. _iis: http://en.wikipedia.org/wiki/Internet_Information_Services

.. _pip: http://en.wikipedia.org/wiki/Pip_%28package_manager%29

.. _WSGI: http://en.wikipedia.org/wiki/Web_Server_Gateway_Interface

.. _HAProxy: http://www.haproxy.org/

.. _Varnish: https://www.varnish-cache.org/

.. _npm: https://www.npmjs.com/