Lemonldap-NG
====================

Lemonldap::NG is a modular Web-SSO based on Apache::Session modules. It
simplifies the build of a protected area with a few changes in the application.

It manages both authentication and authorization and provides headers for
accounting. So you can have a full AAA protection for your web space as
described below.

 1 - Installation
 2 - Authentication, Authorization and Accounting mechanisms
     2.1 - Authentication
     2.2 - Authorization
     2.3 - Accounting
 3 - Session storage system
 4 - Logout system
 5 - Author
 6 - Copyright and licence

1 - INSTALLATION
================

Lemonldap::NG is a different project than Lemonldap and contains all you need
to use and administer it. So softwares, like Lemonldap webmin module, may not
work with Lemonldap::NG.

The Apache module part (Lemonldap::NG::Handler) works both with Apache 1.3.x
and 2.x ie mod_perl 1 and 2 (but not with mod_perl 1.99). Portal and Manager
act as CGI, so they can work everywhere.

See INSTALL file in the whole source tree of Lemonldap::NG for a complete
installation documentation.

To install this module type the following:

   perl Makefile.PL
   make
   make test
   make install

2 - AUTHENTICATION, AUTHORIZATION AND ACCOUNTING MECHANISMS
===========================================================

Warning: Lemonldap::NG configuration has to be edited using the manager unless
you know exactly what you are doing. The parameters discussed here are all in
the configuration tree.

2.1 - Authentication

If a user isn't authenticated and attemps to connect to an area protected by a
Lemonldap::NG compatible handler, he is redirected to a portal. The portal
authenticates user with a ldap bind by default, but you can also use another
authentication sheme like using x509 user certificates (see
Lemonldap::NG::Portal::AuthSSL(3) for more).

Lemonldap::NG use session cookies generated by Apache::Session so as secure as a
128-bit random cookie. You may use the securedCookie options to avoid session
hijacking.

You have to manage life of sessions by yourself since Lemonldap::NG knows
nothing about the L<Apache::Session> module you've choosed, but it's very easy
using a simple cron script because Lemonldap::NG::Portal stores the start
time in the _utime field.
By default, a session stay 10 minutes in the local storage, so in the worth
case, a user is authorized 10 minutes after he lost his rights.

2.2 - Authorization

Authorization is controled only by handlers because the portal knows nothing
about the way the user will choose. When configuring your Web-SSO, you have to:

 * choose the ldap attributes you want to use to manage accounting and
   authorization.
 * create Perl expressions to define user groups (using ldap attributes)
 * create an array foreach virtual host associating URI regular expressions and
   Perl expressions to use to grant access.

Example (See Lemonldap::NG::Common::Conf(3) to see how configuration is stored)

 * Exported variables :

   # Custom-Name    => LDAP attribute
     cn             => cn
     departmentUID  => departmentUID
     login          => uid

 * User groups :

   # Custom-Name => group definition
     group1      => { $departmentUID eq "unit1" or $login = "xavier.guimard" }

 * Area protection:

  # Each VirtualHost has its own configuration
  # associating URL regexp to Perl expression
    * www1.domain.com :
          ^/protected/.*$ => $groups =~ /\bgroup1\b/
          default         => accept
      },
    * www2.domain.com => {
          ^/site/.*$       => $uid eq "admin" or $groups =~ /\bgroup2\b/
          ^/(js|css)       => accept
          default          => deny
      },
  },

2.2.1 - Performance

You can use Perl expressions as complicated as you want and you can use all
the exported LDAP attributes (and create your own attributes: with 'macros'
mechanism) in groups evaluations, area protections or custom HTTP headers
(you just have to call them with a "$").

You have to be careful when choosing your expressions:

 * groups and macros are evaluated each time a user is redirected to the portal
 * virtual host rules and exported headers are evaluated for each request on a
   protected area.

It is also recommanded to use the groups mechanism to avoid having to evaluate
a long expression at each HTTP request:

  # Virtual hosts :
      ...
      www1.domain.com :
          ^/protected/.*$   => $groups =~ /\bgroup1\b/

You can also use LDAP filters, or Perl expression or mixed expressions in
groups definitions. Perl expressions has to be enclosed with {}:

 * group1 => (|(uid=xavier.guimard)(ou=unit1))
 * group1 => {$uid eq "xavier.guimard" or $ou eq "unit1"}
 * group1 => (|(uid=xavier.guimard){$ou eq "unit1"})

It is also recommanded to use Perl expressions to avoid requiering the LDAP
server more than 2 times per authentication.

2.3 - Accounting

2.3.1 - Logging portal access>

Lemonldap::NG::Portal doesn't log anything by default, but it's easy to
overload log method for normal portal access.

2.3.2 - Logging application access

Because a Web-SSO knows nothing about the protected application, it can't do
more than logging URL. As Apache does this fine, L<Lemonldap::NG::Handler>
gives it the name to used in logs. The whatToTrace parameter indicates
which variable Apache has to use ($uid by default).

The real accounting has to be done by the application itself which knows the
result of SQL transaction for example.

Lemonldap::NG can export HTTP headers either using a proxy or protecting
directly the application. By default, the Auth-User field is used but you can
change it using the exportedHeaders parameters (in the Manager, each virtual
host as custom headers branch). This parameters contains an associative array
per virtual host:

 * keys are the names of the choosen headers
 * values are Perl expressions where you can use user datas stored in the
   global storage.

Example:

 * www1.domain.com :
        Auth-User     => $uid
        Unit          => $ou
 * www2.domain.com :
        Authorization => "Basic ".encode_base64($employeeNumber.":dummy")
        Remote-IP     => $ip

3 - SESSION STORAGE SYSTEM

Lemonldap::NG use 3 levels of cache for authenticated users:

 * an Apache::Session::* module used by lemonldap::NG::Portal to store
   authenticated user parameters,
 * a Cache::Cache* module used by Lemonldap::NG::Handler to share authenticated
   users between Apache's threads or processus and of course between virtual
   hosts on the same machine
 * Lemonldap::NG::Handler variables : if the same user use the same thread or
   processus a second time, no request are needed to grant or refuse access.
   This is very efficient with HTTP/1.1 Keep-Alive system.

So the number of request to the central storage is limited to 1 per active
user each 10 minutes.

Lemonldap::NG is very fast, but you can increase performance using a 
Cache::Cache module that does not use disk access.

4 - LOGOUT SYSTEM

Lemonldap::NG provides a single logout system: you can use it by adding a link
to the portal with "logout=1" parameter in the portal (See
Lemonldap::NG::Portal) and/or by configuring handler to intercept some URL
(See Lemonldap::NG::Handler) directly in the manager interface or in apache
configuration file. The logout system:
 * delete session in the global session storage,
 * replace Lemonldap::NG cookie by '',
 * delete handler caches only if logout action was started from a protected
   application and only in the current Apache server. So in other servers,
   session is still in cache for 10 minutes maximum if the user was connected
   on it in the last 10 minutes.

5 - AUTHOR

Xavier Guimard, x.guimard@free.fr

6 - COPYRIGHT AND LICENSE

Copyright (C) 2005-2007 by Xavier Guimard x.guimard@free.fr

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.4 or,
at your option, any later version of Perl 5 you may have available.
