1. Auth_db Module

Jan Janak

   FhG Fokus
   <jan@iptel.org>

Jakob Schlyter

   <jakob@schlyter.se>

   Copyright © 2002, 2003 FhG FOKUS
     __________________________________________________________________

   1.1. Overview
   1.2. Dependencies
   1.3. Parameters

        1.3.1. db_url (string)
        1.3.2. user_column (string)
        1.3.3. domain_column (string)
        1.3.4. password_column (string)
        1.3.5. rpid_column (string)
        1.3.6. calculate_ha1 (integer)
        1.3.7. plain_password_column (string)
        1.3.8. password_column_2 (string)
        1.3.9. use_rpid (integer)

   1.4. Functions

        1.4.1. www_authorize(realm, table)
        1.4.2. proxy_authorize(realm, table)

1.1. Overview

   This module contains all authentication related functions that need the
   access to the database. This module should be used together with auth
   module, it cannot be used independently because it depends on the
   module. Select this module if you want to use database to store
   authentication information like subscriber usernames and passwords. If
   you want to use radius authentication, then use auth_radius instead.

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.
     * database.  Any database module (currently mysql, postgres, dbtext)

1.3. Parameters

1.3.1. db_url (string)

   This is URL of the database to be used. Value of the parameter depends
   on the database module used. For example for mysql and postgres modules
   this is something like mysql://username:password@host:port/database.
   For dbtext module (which stores data in plaintext files) it is
   directory in which the database resides.

   Default value is "mysql://serro:47serro11@localhost/ser".

   Example 1. db_url parameter usage
modparam("auth_db", "db_url", "mysql://foo:bar@foobar.org/ser")

1.3.2. user_column (string)

   This is the name of the column holding usernames. Default value is fine
   for most people. Use the parameter if you really need to change it.

   Default value is "username".

   Example 2. user_column usage
modparam("auth_db", "user_column", "user")

1.3.3. domain_column (string)

   This is the name of the column holding domains of users. Default value
   is fine for most people. Use the parameter if you really need to change
   it.

   Default value is "domain".

   Example 3. domain_column usage
modparam("auth_db", "domain_column", "domain")

1.3.4. password_column (string)

   This is the name of the column holding passwords. Passwords can be
   either stored as plain text or pre-calculated HA1 strings. HA1 strings
   are MD5 hashes of username, password, and realm. HA1 strings are more
   safe because the server doesn't need to know plaintext passwords and
   they cannot be obtained from HA1 strings.

   Default value is "ha1".

   Example 4. password_column usage
modparam("auth_db", "password_column", "password")

1.3.5. rpid_column (string)

   This is the name of the column holding information for the
   Remote-Party-ID header field. Default value is fine for most people.
   Use the parameter if you really need to change it.

   Default value is "rpid".

   Example 5. rpid_column usage
modparam("auth_db", "rpid_column", "remote_party_id")

1.3.6. calculate_ha1 (integer)

   This parameter tells server whether it should read plaintext password
   from the database or HA1 string. If the parameter is set to 1 then the
   server will assume that the column pointed to by plain_password_column
   contains plaintext passwords and it will calculate HA1 strings on the
   fly.

   If the parameter is set to 0 then the server assumes that the database
   contains HA1 strings directly and will not calculate them. In this case
   it will use value of password_column as name of column with HA1
   password. If username parameter of credentials contains also @domain
   (some user agents put domain in username parameter), then column
   pointed to by password_column_2 parameter will be used instead. This
   column should also contain HA1 strings but they should be calculated
   including the domain in the username parameter (as opposed to
   password_column which (when containing HA1 strings) should always
   contains HA1 strings calculated without domain in username.

   This ensures that the authentication will always work when using
   pre-calculated HA1 string, not depending on the presence of the domain
   in username.

   Default value of this parameter is 0.

   Example 6. calculate_ha1usage
modparam("auth_db", "calculate_ha1", 1)

1.3.7. plain_password_column (string)

   This parameter holds the name of column holding plain text password.
   This column is used when calculate_ha1 is set.

   Default value is "password".

   Example 7. plain_password_column usage
modparam("auth_db", "plain_password_column", "password")

1.3.8. password_column_2 (string)

   As described in the previous section this parameter contains name of
   column holding pre-calculated HA1 string that were calculated including
   the domain in the username. This parameter is used only when
   calculate_ha1 is set to 0 and user agent send a credentials containing
   the domain in the username.

   Default value of the parameter is ha1b.

   Example 8. password_column_2 usage
modparam("auth_db", "password_column_2", "ha1_2")

1.3.9. use_rpid (integer)

   This parameter specifies whether the server should fetch a value for
   the Remote-Party-ID header field from the database.

   If the parameter is set to 1 the server expects to find a value for
   this header in the column specified by the rpid_column parameter.

   Default value of this parameter is 0.

   Example 9. use_rpidusage
modparam("auth_db", "use_rpid", 1)

1.4. Functions

1.4.1. www_authorize(realm, table)

   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.

   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.
       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.
     * table.  Table to be used to lookup usernames and passwords (usually
       subscribers table).

   Example 10. www_authorize usage
...
if (www_authorize("iptel.org", "subscriber")) {
    www_challenge("iptel.org", "1");
};
...

1.4.2. proxy_authorize(realm, table)

   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.

   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.
       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.
     * table - Table to be used to lookup usernames and passwords (usually
       subscribers table).

   Example 11. proxy_authorize usage
...
if (!proxy_authorize("", "subscriber)) {
    proxy_challenge("", "1");  # Realm will be autogenerated
};
...
