Apache module mod_intercept_form_submit
=======================================

Apache module to intercept submission of application login forms. It
retrieves the login and password information from the POST HTTP
request, runs PAM authentication with those credentials, and sets the
REMOTE_USER environment variable if the authentication passes.

Module configuration
--------------------

The module needs to be configured for Location that the application
uses to process the login form POST requests. The configuration has to
specify three values:

    InterceptFormPAMService name_of_the_PAM_service

      The PAM service to authenticate against.

    InterceptFormLogin the_login_field_name

      Name of the login field in the login form, and thus the login
      parameter in the POST request.

    InterceptFormPassword the_password_field_name

      Name of the password field in the login form, and thus the
      password parameter in the POST request.

All three parameters need to be specified or the interception will not
be enabled.

Optionally, list of logins to ignore (never attempt to authenticate)
can be specified:

    InterceptFormLoginSkip one_login or_more_logins

Example:

    <Location /users/login>
      InterceptFormPAMService http_application_sss
      InterceptFormLogin login[login]
      InterceptFormPassword login[password]
      InterceptFormLoginSkip admin
    </Location>

The PAM service needs to be configured. For the above shown
http_application_sss example, file /etc/pam.d/http_application_sss
could be created with content

    auth    required   pam_sss.so

to authenticate against sssd.

On SELinux enabled systems, boolean allow_httpd_mod_auth_pam needs to
be enabled:

    setsebool -P allow_httpd_mod_auth_pam 1

Building from sources
---------------------

When building from sources, command

    apxs -i -a -c mod_intercept_form_submit.c -lpam -Wall -pedantic

should build and install the module.

License
-------

Copyright 2013 Jan Pazdziora

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.