DESCRIPTION

This program is part of the DACS suite.

The autologin CGI program, in conjunction with appropriate Apache and DACS configuration, is used to automatically convert an identity already established by Apache into a DACS identity. After standard HTTP Basic or Digest Authentication (RFC 2617) has been performed successfully, autologin causes DACS credentials to be generated and returned. This capability lets DACS leverage any of Apache's existing authentication methods through simple configuration.

A user that has completed Basic or Digest Authentication (following a 401 Authorization Required response from the web server) invokes autologin. autologin generates credentials by constructing a request to dacs_authenticate(8). The value of the REMOTE_USER environment variable, as set by Apache, is used by dacs_authenticate to derive the DACS username.

OPTIONS

Only the standard dacsoptions command line arguments are recognized.

EXAMPLE

A typical use of autologin is to support coexistence on the same Web site of DACS-wrapped content, services. legacy applications, or content deployed under HTTP Basic or Digest Authentication. The following example illustrates configuration of Apache and DACS for the deployment under HTTP Basic Authentication of a web log application, Blogo. Blogo will be deployed within a DACS jurisdiction METALOGIC. The URI space of interest will be example.com/metalogic/*.

In the Apache configuration file httpd.conf, a Location is defined for the Blogo application under Basic Authentication:

<Location /metalogic/blogo>
  AuthType Basic
  AuthName "FedDev"
  AuthUserFile /local/etc/auth-file
  Require valid-user
# Note: For Apache 2.4, instead use:
# Require dacs-authz
</Location>

A Location under Basic Authentication also is defined where the autologin utility is deployed:

<Location /metalogic/dacs-native>
  AuthType Basic
  AuthName "FedDev"
  AuthUserFile /local/etc/auth-file
  Require valid-user
# Note: For Apache 2.4, instead use:
# Require dacs-authz
</Location>

At the same time, other content in METALOGIC is protected by DACS:

<Location /metalogic/dev>
  Allow from all
  AuthType DACS
  AuthDACS dacs-acs
  Require valid-user
# Note: For Apache 2.4, instead use:
# Require dacs-authz
</Location>

In the DACS configuration file, dacs.conf, jurisdiction METALOGIC is configured as follows:

<Jurisdiction uri="example.com/metalogic">

JURISDICTION_NAME "METALOGIC"

ACS_ERROR_HANDLER "902 https://example.com/metalogic/dacs-native/autologin\
?DACS_CONF=${Conf::DACS_CONF}&amp;JURISDICTION_URI=example.com/metalogic"

<!-- Authenticate using Apache Basic/Digest Auth. -->
<Auth id="native">
URL "https://example.com/metalogic/dacs/local_native_authenticate"
STYLE "native"
CONTROL "sufficient"
</Auth>

</Jurisdiction>

The preceding configuration results in the following behaviour. A user accessing Blogo directly (https://example.com/metalogic/blogo) is challenged to enter a valid username and password (with respect to the Apache accounts in /local/etc/auth-file). If the user subsequently accesses DACS content requiring DACS authentication but no DACS credentials are present:

If the user accesses DACS content without first visiting the Blogo application, the 902 event handler fires, resulting in a browser redirect to autologin. Since autologin is itself behind Basic Authentication, the user will be prompted for a username and password. Once Basic Authentication succeeds, autologin is invoked with REMOTE_USER set (and therefore so is dacs_authenticate) and the process described above is repeated.

autologin may also be used as the target of an explicit authentication link. For example:

<a href="https://example.com/metalogic/dacs-native/autologin?\
DACS_CONF=/local/dacs/federations/example.com/dacs.conf&\
DACS_SET_JURISDICTION=METALOGIC&\
JURISDICTION_URI=example.com/metalogic&\
DACS_ERROR_URL=https://example.com">Login</a>

Following the link above results first in a Basic Authentication challenge and then sets DACS credentials in jurisdiction METALOGIC.

NOTES

autologin cannot generate credentials in a jurisdiction other than the one in which autologin is deployed.

The behaviour of browsers with respect to the HTTP 401 Authorization status code may have undesired consequences. For example, browsers continually send username and password in any matching request. If a user does not exit the browser, this can result in DACS credentials automatically being regenerated long after their configured lifetime has expired. RFC 2617 provides no way for the server to "signout" a user, and neither do many browsers other than by ending the browser session or clearing browser history appropriately. This makes it inconvenient for a user to reauthenticate with respect to DACS using this technique.

DIAGNOSTICS

The program exits 0 if successful, 1 if an error occurred.

SEE ALSO

dacs_authenticate(8) (in particular, the native authentication style), dacs_autologin_ssl(8), dacs_acs(8), dacs.conf(5)

AUTHOR

Metalogic Software Corp. and Distributed Systems Software (www.dss.ca)

COPYING

Copyright © 2003-2018 Distributed Systems Software. See the LICENSE file that accompanies the distribution for licensing information.