Auth_radius Module

Jan Janak

   FhG Fokus

Juha Heinanen

   Song Networks

Stelios Sidiroglou-Douskos

Bogdan-Andrei Iancu

   voice-system.ro

Edited by

Jan Janak

   Copyright © 2002, 2003 FhG FOKUS

   Copyright © 2005 voice-system.ro
     __________________________________________________________

   Table of Contents
   1. User's Guide

        1.1. Overview
        1.2. Additional Credentials
        1.3. Dependencies

              1.3.1. OpenSER Modules
              1.3.2. External Libraries or Applications

        1.4. Exported Parameters

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

        1.5. Exported Functions

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

   2. Developer's Guide
   3. Frequently Asked Questions

   List of Examples
   1-1. "SIP-AVP" RADIUS AVP exmaples
   1-2. radius_config parameter usage
   1-3. service_type parameter usage
   1-4. radius_www_authorize usage
   1-5. proxy_authorize usage
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Chapter 1. User's 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 OpenSER 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)
....
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1.3. Dependencies

1.3.1. OpenSER 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
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1.3.2. External Libraries or Applications

   The following libraries or applications must be installed
   before compilling OpenSER 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
   "/opt/etc/radiusclient-ng/radiusclient.conf".

   Example 1-2. radius_config parameter usage
modparam("auth_radius", "radius_config", "/etc/radiusclient.conf")
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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)
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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 1-4. radius_www_authorize usage
...
if (!radius_www_authorize("siphub.net")) {
        www_challenge("siphub.net", "1");
};
...
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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 1-5. 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
...
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Chapter 2. Developer's Guide

   The module does not provide any API to use in other OpenSER
   modules.
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Chapter 3. Frequently Asked Questions

   3.1. Where can I find more about OpenSER?
   3.2. Where can I post a question about this module?
   3.3. How can I report a bug?

   3.1. Where can I find more about OpenSER?

   Take a look at http://www.openser.org/.

   3.2. Where can I post a question about this module?

   First at all check if your question was already answered on one
   of our mailing lists:

     * User Mailing List -
       http://lists.openser.org/cgi-bin/mailman/listinfo/users
     * Developer Mailing List -
       http://lists.openser.org/cgi-bin/mailman/listinfo/devel

   E-mails regarding any stable OpenSER release should be sent to
   <users@lists.openser.org> and e-mails regarding development
   versions should be sent to <devel@lists.openser.org>.

   If you want to keep the mail private, send it to
   <team@lists.openser.org>.

   3.3. How can I report a bug?

   Please follow the guidelines provided at:
   http://sourceforge.net/tracker/?group_id=139143.
