Auth_radius Module

Jan Janak

   FhG Fokus
   <jan@iptel.org>

Juha Heinanen

   Song Networks
   <jh@song.fi>

Stelios Sidiroglou-Douskos

Bogdan-Andrei Iancu

   voice-system.ro
   <bogdan@voice-system.ro>

Edited by

Jan Janak

   <jan@iptel.org>

   Copyright  2002, 2003 FhG FOKUS

   Copyright  2005 voice-system.ro
   Revision History
   Revision $Revision: 3898 $ $Date: 2008-03-08 01:03:56 +0200
                              (Sat, 08 Mar 2008) $
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Additional Credentials
        1.3. Dependencies

              1.3.1. OpenSIPS Modules
              1.3.2. External Libraries or Applications

        1.4. Exported Parameters

              1.4.1. radius_config (string)
              1.4.2. service_type (integer)
              1.4.3. use_ruri_flag (integer)

        1.5. Exported Functions

              1.5.1. radius_www_authorize(realm)
              1.5.2. radius_proxy_authorize(realm [, uri_user])

   List of Examples

   1.1. "SIP-AVP" RADIUS AVP exmaples
   1.2. radius_config parameter usage
   1.3. service_type parameter usage
   1.4. use_ruri_flag parameter usage
   1.5. radius_www_authorize usage
   1.6. proxy_authorize usage

Chapter 1. Admin Guide

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-ng
   library version 0.5.0 or higher which is available from
   http://developer.berlios.de/projects/radiusclient-ng/.

1.2. Additional Credentials

   When performing authentification, the RADIUS server may include
   in the response additional credentials. This scheme is very
   useful in fetching additional user information from the RADIUS
   server without making extra queries.

   The additional credentials are embedded in the RADIUS reply as
   AVPs "SIP-AVP". The syntax of the value is:
     * value = SIP_AVP_NAME SIP_AVP_VALUE
     * SIP_AVP_NAME = STRING_NAME | '#'ID_NUMBER
     * SIP_AVP_VALUE = ':'STRING_VALUE | '#'NUMBER_VALUE

   All additional credentials will be stored as OpenSIPS AVPs
   (SIP_AVP_NAME = SIP_AVP_VALUE).

   The RPID value may be fetch via this mechanism.

   Example 1.1. "SIP-AVP" RADIUS AVP exmaples
....
"email:joe@yahoo.com"
    - STRING NAME AVP (email) with STRING VALUE (joe@yahoo.com)
"#14:joe@yahoo.com"
    - ID AVP (14) with STRING VALUE (joe@yahoo.com)
"age#28"
    - STRING NAME AVP (age) with INTEGER VALUE (28)
"#14#28"
    - ID AVP (14) with INTEGER VALUE (28)
....

1.3. Dependencies

1.3.1. OpenSIPS Modules

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

1.3.2. External Libraries or Applications

   The following libraries or applications must be installed
   before compilling OpenSIPS with this module loaded:
     * radiusclient-ng 0.5.0 or higher -- library and development
       files. See
       http://developer.berlios.de/projects/radiusclient-ng/.

1.4. Exported Parameters

1.4.1. radius_config (string)

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

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

   Example 1.2. radius_config parameter usage
modparam("auth_radius", "radius_config", "/etc/radiusclient.conf")

1.4.2. 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 1.3. service_type parameter usage
modparam("auth_radius", "service_type", 15)

1.4.3. 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 1.4. use_ruri_flag parameter usage
modparam("auth_radius", "use_ruri_flag", 22)

1.5. Exported Functions

1.5.1. 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.

   Negative codes may be interpreted as follows:
     * -5 (generic error) - some generic error occurred and no
       reply was sent out;
     * -4 (no credentials) - credentials were not found in
       request;
     * -3 (stale nonce) - stale nonce;

   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.
       The string may contain pseudo variables.

   This function can be used from REQUEST_ROUTE.

   Example 1.5. radius_www_authorize usage
...
if (!radius_www_authorize("siphub.net")) {
        www_challenge("siphub.net", "1");
};
...

1.5.2. radius_proxy_authorize(realm [, uri_user])

   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. For more about the
   negative return codes, see the above function.

   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 parameters 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. This is usually one of the domains the
       proxy is responsible for. If an empty string "" is used
       then the server will generate realm from host part of From
       header field URI.
       The string may contain pseudo variables.
     * uri_user - Uri_user is an optional pseudo variable
       parameter whose value, if present, will be given to Radius
       server as value of SIP-URI-User check item. If uri_user
       pseudo variable parameter is not present, the server will
       generate SIP-URI-User check item value from user part of
       To/From URI.

   This function can be used from REQUEST_ROUTE.

   Example 1.6. proxy_authorize usage
...
if (!radius_proxy_authorize("")) {   # Realm and URI user will be autoge
nerated
        proxy_challenge("", "1");
};
...
if (!radius_proxy_authorize("$pd", "$pU")) { # Realm and URI user are ta
ken
        proxy_challenge("$pd", "1");         # from P-Preferred-Identity
};                                           # header field
...
