NAME
Apache::AuthCookieURL - Perl Authentication and Authorization or session management via cookies or URL munging
SYNOPSIS
In httpd.conf
# Your module that overrides AuthCookieURL methods
PerlModule My::AuthCookieURLHandler
# Or to use simple session generation w/o persistence
#PerlModule Apache::AuthCookieURL
## Some settings -- "Whatever" is set by AuthName ##
# most can be set within <directory> sections
# Send expires with cookie
PerlSetVar WhateverExpires +90d
# Other cookie settings
#PerlSetVar WhateverDomain some.domain
# This can only be set to "/" if using URL sessions
#PerlSetVar WhateverPath /path
#PerlSetVar WhateverSecure 1
# Login script to call
PerlSetVar WhateverLoginScript /login.pl
# Or for just session management without a login script
#PerlSetVar WhateverLoginScript NONE
# Debugging options
#PerlSetVar AuthCookieURLDebug 5
# Disable cookies (only URL based sessions)
#PerlSetVar WhateverNoCookie 1
# Define a string that indicates to AuthCookieURL
# what a session looks like
# This can only be in main config
#PerlSetVar SessionPrefix Session-
# This block enables URL session handling
PerlTransHandler Apache::AuthCookieURLHandler->URLsession
ErrorDocument 302 /MISSING
ErrorDocument 301 /MISSING
<Location /MISSING>
SetHandler perl-script
PerlHandler Apache::AuthCookieURLHandler->error_document
</Location>
<Location /protected>
AuthType Apache::AuthCookieURLHandler
AuthName Whatever
PerlAuthenHandler Apache::AuthCookieURLHandler->authenticate
PerlAuthzHandler Apache::AuthCookieURLHandler->authorize
require valid-user
</Location>
# provide open access to some areas below
<Location /protected/open>
PerlSetVar DisableAuthCookieURL 1
</Location>
# or if the entire directory tree was protected
<Location /images>
PerlSetVar DisableAuthCookieURL 1
</Location>
# Make sure the login script can be run
<Files login.pl>
Options +ExecCGI
SetHandler perl-script
PerlHandler Apache::Registry
</Files>
# LOGIN is the action defined by the login.pl script
<Files LOGIN>
AuthType Apache::AuthCookieURLHandler
AuthName Whatever
SetHandler perl-script
PerlHandler Apache::AuthCookieURLHandler->login
</Files>
# Note: If protecting the entire web site (from root down) then
# the action *must* be C</LOGIN> as the module looks for this string.
# better to just invalidate the session, of course
<Files LOGOUT>
AuthType Apache::AuthCookieURLHandler
PerlSetVar WhateverLogoutURI /
AuthName Whatever
SetHandler perl-script
PerlHandler Apache::AuthCookieURLHandler->logout
</Files>DESCRIPTION
** Warning: beta software. This should be used for testing purposes only. That said, there are a few people using it and I've been using it for a few months without problem. The interface may change (or disappear) without notice. Please report any problems or comments back to Bill Moseley <moseley@hank.org>.
This module is a modification of Ken Williams <ken@forum.swarthmore.edu> Apache::AuthCookie. Please see perldoc Apache::AuthCookie for complete instructions. As this is intended to be a drop-in replacement for Apache::AuthCookie you may wish to install and test with Ken's Apache::AuthCookie before trying AuthCookieURL.
Basically, this module allows you to catch any unauthenticated access and redirect to a login script that you define. The login script posts credentials (e.g. username and password) and your module can then validate and provide a session key. The session key is sent in a cookie, and also in a munged URL and a redirect is issued and the process starts all over.
Typically, you will write your own module that will override methods in Apache::AuthCookieURL. These methods are described completely in Ken's Apache::AuthCookie. Your methods will be used to generate and validate session keys. You can use Apache::AuthCookieURL without overriding its methods and then AuthCookieURL can be used as a simple session manager.
With this module you should be able to enable session management for an entire site using <Location />, and then allow access to, say, the images directory, and also require password access to other locations. One issue at this point is that the session key is stripped from URLs in a Trans handler. So you would need to use cookies to use different session keys for different parts of your web tree.
Apache::AuthCookieURL adds the following features to Apache::AuthCookie.
URL munging
If the PerlTransHandler is enabled in httpd.conf the session key will also be placed in the URL. The session will be removed from the URL if cookies are enabled on the next request. Typically, someone visiting your site with cookies enabled will never see the munged URL.
To make URL sessions work you must use relative links in your documents so the client/browser knows to place the session key on all links. CGI scripts can also access the session information via the environment.
Simple Session Management
If the login script is set to `NONE' with PerlSetVar WhateverLoginScript NONE then Apache::AuthCookeURL acts like a simple session manager: your module will provide a new session key if one is not provided with the request, or if the one provided is invalid.
Really Simple Session Management
Apache::AuthCookieURL provides default authen_cred() and authen_ses_key() methods that generates a (questionably) random session key. This means you can use AuthCookieURL directly without subclassing for really simple session management without any persistence of session keys.
Unless you are not subclassing this module (and using the default methods provide), your own module must define two methods: authen_cred() and authen_ses_key(), and then subclass by including Apache::AuthCookieURL in your module's @ISA array. Again, please see Apache::AuthCookie for complete documentation.
authen_cred()
This method verifies the credentials (e.g. username/password) and returns a session key. If the credentials are not acceptable then you can return a list, with the second element being an error message that is placed in a cookie. This allows your login script to display a failure reason. This method is needed since a redirect is done before your login script is executed again. Of course, this requires that the client has cookies enabled.
Another method is to return a session key that is really an error code and generate messages based on that returned session (error) code.
authen_ses_key()
This method's job is to validate and convert a session key into a username and return it. AuthCookieURL places the returned value into $ENV{REMOTE_USER}.
CONFIGURATION SETTINGS
Configuration settings are set with the PerlSetVar directive:
PerlSetVar WhateverExpires +90d"Whatever" is whatever the current AuthName is set. I think I might remove this and instead just use the settings as Apache dir_merge returns them. In other words, if you want a setting to override a global setting, then use it within a <directory>, <file>, or <location> section.
AuthCookieURLDebug
Sets the debugging level. Since some debugging info is generated in the Trans handler this needs to be set in the main httpd config. Default is 0.
Example: PerlSetVar AuthCookieURLDebug 5
SessionPrefix
SessionPrefix sets the prefix used by the Trans handler to recognize the session in the URL (thus needs to be set in the main config), and to create the session ID. Default is 'Session-'.
Example: PerlSetVar SessionPrefix ID-
WhateverCache
UNLESS set then $r->no_cache(1) will be called when processing the login and logout requests. Defaults to unset and thus $r->no_cache(1) IS called.
Example: PerlSetVar WhateverCache 1
WhateverLogoutURI
Sets where you are redirected after requesting the logout URL (see SYNOPSIS). Defaults to '/'.
Example: PerlSetVar WhateverLogoutURI /gone.html
DisableAuthCookieURL
This causes the Authen and Authz handlers to return OK. In other words,
<Location /protected/notprotected> PerlSetVar DisableAuthCookieURL 1 </Location>Allows full access to the notprotected directory.
WhateverLoginScript
This sets the Login script to be executed when authorization is required (no valid session key was sent by cookie or URL). This login script can be a CGI script, Apache::Registry script, or a mod_perl handler.
If set to `NONE' then AuthCookieURL will be in simple session management mode. AuthCookieURL->login will be called which calls authen_cred() to generate a session key. authen_cred() should just return a session key without checking the credentials.
If you do not override AuthCookieURL::authen_cred(), then AuthCookieURL::authen_cred() simply returns this for a session key.
return time . $$ . int rand $$;Example: PerlSetVar WhateverLoginScript /login.pl PerlSetVar WhateverLoginScript NONE
WhateverNoCookie
Turns off cookies.
Example: PerlSetVar WhateverNoCookie 1
Whatever(Path|Expires|Domain|Secure)
These all control the values sent in cookies. Path, if used, must be '/' if using URL-based sessions.
Example: PerlSetVar WhateverPath /
ENVIRONMENT AND NOTES
Apache::AuthCookieURL sets some environment variables and Apache notes:
authen_ses_key() returns a value that is placed in $ENV{REMOTE_USER}. authen_ses_key() normally converts the session key into a username.
$ENV{SESSION} contains the current session key
$ENV{AuthCookieURLReason} contains the reason authentication failed. Either 'no_session_provided' or 'bad_session_provided'.
$r->notes( 'URI_Session' ) is the session extracted from the URI
$r->notes('Session_prefix') is the prefix used with the session keys, of course.
$r->notes( 'SESSION' ) is the full session, including the prefix.
WARNING
URL munging has security issues. Session keys can get written to access logs, cached by browsers, leak outside your site, and are broken if your pages use absolute links to other pages on-site.
TO DO
Apache::AuthCookieURL uses error documents to try to fixup any redirects. The obvious example is when a request is made for a directory without a trailing slash and Apache issues a redirect. (Actually, AuthCookieURL tries to detect this case and rewrite the URL before Apache redirects.) I wish I knew a better way to fixup Location: headers in redirects without sub-requesting every request. There's no way to catch a CGI script or module that might issue a Location: header or REDIRECT. I guess that's left for Apache 2.0 when all output can be filtered.
REQUIRED
mod_perl 1.24, Apache::Cookie
AUTHOR
Bill Moseley <moseley@hank.org> made minor changes to Ken Williams' <ken@forum.swarthmore.edu> Apache::AuthCookie.
Thanks very much to Ken for Apache::AuthCookie.
VERSION
$Revision: 1.3 $