1. Auth_radius Module

Jan Janak

   FhG Fokus
   <jan@iptel.org>

Juha Heinanen

   Song Networks
   <jh@song.fi>

Stelios Sidiroglou-Douskos

   Copyright © 2002, 2003 FhG FOKUS
     __________________________________________________________________

   1.1. Overview
   1.2. Dependencies
   1.3. Parameters

        1.3.1. radius_config (string)
        1.3.2. service_type (integer)
        1.3.3. use_ruri_flag (integer)

   1.4. Functions

        1.4.1. radius_www_authorize(realm)
        1.4.2. radius_proxy_authorize(realm)

1.1. Overview

   This module contains functions that are used to perform authentication
   using a Radius server. Basically the proxy will pass along the
   credentials to the radius server which will in turn send a reply
   containing result of the authentication. So basically the whole
   authentication is done in the Radius server. Before sending the request
   to the radius server we perform some sanity checks over the credentials
   to make sure that only well formed credentials will get to the server.
   We have implemented radius authentication according to
   draft-sterman-aaa-sip-00. This module requires radiusclient library
   version 0.5.0 or higher which is available from
   http://developer.berlios.de/projects/radiusclient-ng/.

1.2. Dependencies

   The module depends on the following modules (in the other words the
   listed modules must be loaded before this module):
     * auth.  Generic authentication functions.

1.3. Parameters

1.3.1. radius_config (string)

   This is the location of the configuration file of radius client
   libraries.

   Default value is "/usr/local/etc/radiusclient/radiusclient.conf".

   Example 1. radius_config parameter usage
modparam("auth_radius", "radius_config", "/etc/radiusclient.conf")

1.3.2. service_type (integer)

   This is the value of the Service-Type radius attribute to be used. The
   default should be fine for most people. See your radius client include
   files for numbers to be put in this parameter if you need to change it.

   Default value is "15".

   Example 2. service_type usage
modparam("auth_radius", "service_type", 15)

1.3.3. use_ruri_flag (integer)

   When this parameter is set to the value other than "-1" and the request
   being authenticated has flag with matching number set via setflag()
   function, use Request URI instead of uri parameter value from the
   Authorization / Proxy-Authorization header field to perform RADIUS
   authentication. This is intended to provide workaround for misbehaving
   NAT / routers / ALGs that alter request in the transit, breaking
   authentication. At the time of this writing, certain versions of
   Linksys WRT54GL are known to do that.

   Default value is "-1".

   Example 3. use_ruri_flag usage
modparam("auth_radius", "use_ruri_flag", 22)

1.4. Functions

1.4.1. radius_www_authorize(realm)

   The function verifies credentials according to RFC2617. If the
   credentials are verified successfully then the function will succeed
   and mark the credentials as authorized (marked credentials can be later
   used by some other functions). If the function was unable to verify the
   credentials for some reason then it will fail and the script should
   call www_challenge which will challenge the user again.

   This function will, in fact, perform sanity checks over the received
   credentials and then pass them along to the radius server which will
   verify the credentials and return whether they are valid or not.

   Meaning of the parameter is as follows:
     * realm - Realm is a opaque string that the user agent should present
       to the user so he can decide what username and password to use.
       Usually this is domain of the host the server is running on.
       If an empty string "" is used then the server will generate it from
       the request. In case of REGISTER requests To header field domain
       will be used (because this header field represents a user being
       registered), for all other messages From header field domain will
       be used.

   Example 4. radius_www_authorize usage
...
if (!radius_www_authorize("iptel.org")) {
    www_challenge("iptel.org", "1");
};
...

1.4.2. radius_proxy_authorize(realm)

   The function verifies credentials according to RFC2617. If the
   credentials are verified successfully then the function will succeed
   and mark the credentials as authorized (marked credentials can be later
   used by some other functions). If the function was unable to verify the
   credentials for some reason then it will fail and the script should
   call proxy_challenge which will challenge the user again.

   This function will, in fact, perform sanity checks over the received
   credentials and then pass them along to the radius server which will
   verify the credentials and return whether they are valid or not.

   Meaning of the parameter is as follows:
     * realm - Realm is a opaque string that the user agent should present
       to the user so he can decide what username and password to use.
       Usually this is domain of the host the server is running on.
       If an empty string "" is used then the server will generate it from
       the request. From header field domain will be used as realm.

   Example 5. proxy_authorize usage
...
if (!radius_proxy_authorize("")) {
    proxy_challenge("", "1");  # Realm will be autogenerated
};
...