# -*- fundamental -*-
+# This is part of CGI::Auth::Flexible, a perl CGI authentication module.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version, with the "CAF Login Exception"
+# as published by Ian Jackson (version 1, or at your option any
+# later version) as an Additional Permission.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+
+
=head1 NAME
CGI::Auth::Flexible - web authentication optionally using cookies
=head3 Simple applications
-The simplist usage is to call C<< $request->check_ok() >> which will
+The simplest usage is to call C<< $request->check_ok() >> which will
check the user's authentication. If the user is not logged in it will
generate a login form (or redirection or other appropriate page) and
-return false; your application should not then processing that request
+return false; your application should not then process that request
any further. If the user is logged in it will return true.
Various hooks are provided to customise the responses generated by
After C<check_ok> returns true you should go ahead and process the
request; you can use C<< $request->get_username >> to find out which
user the request came from.
+You may also need to call C<check_mutate> and/or C<check_nonpage>
+- see below.
-=head2 Sophisticated applications
+=head3 Sophisticated applications
If you want to handle the control flow and to generate login forms,
redirections, etc., yourself, you can say
C<< $divert = $request->check_divert >>. This returns undef if
-the user is logged in, or I<divert spec> if some kind of login
+the user is logged in, or
a I<divert spec> if some kind of login
page or diversion should be generated. See L</DIVERT SPEC> below for
details of how to deal with the return value.
=head3 Mutation-ignorant applications
-By default CGI::Auth::Flexible does not permit external links into
-your site. All GET requests give a "click to continue" page which
+By default CGI::Auth::Flexible does not permit external deep links
+into your site.
+All GET requests give a "click to continue" page which
submits a form which loads your app's main page. In this
configuration all your application's forms and AJAX requests should
-use C<POST>. This restriction arises from complicated deficiencies
-in the web's security architecture.
+use C<POST>.
Such applications are also not able to provide user-specific CSS
stylesheets, javascript, favicons, etc.
+This restriction arises from complicated deficiencies
+in the web's security architecture.
+
=head3 Mutation-aware applications
The alternative is for your application to always make a special check
CGI::Auth::Generic. This form parameter will be checked by
C<check_ok>/C<check_divert> and should be ignored by your application.
-By default the hidden parameter is called C<caf_assochash>.
+By default the hidden parameter is called C<caf__assochash>.
After calling C<check_ok> or C<check_divert> the value to put in your
form can be obtained from C<secret_hidden_val>; C<secret_hidden_html>
been called. (In the case of C<check_ok> it won't normally be sensible
to call these functions unless C<check_ok> returned true.)
+=over
+
=item C<< $authreq->get_divert() >>
Returns the value previously returned by C<check_divert>.
is well and the request should proceed, or it will die, like
C<check_mutate>.
+=back
+
=head1 RESPONSE-RELATED FUNCTIONS AND METHODS
+=over
+
=item C<< $authreq->url_with_query_params($params, [$nonpagetype]) >>
Convenience function which returns a url for a GET request to this
cookie in the forms generated by C<check_ok>. You may also set it
yourself (and indeed you must do so if you use C<check_divert>).
+=item C<< $authreq->_chain_params() >>
+
+Returns a hash of the "relevant" parameters to this request, in a form
+suitable for C<url_with_query_params>. This is all of the query
+parameters which are not related to CGI::Auth::Flexible. The
+PATH_INFO from the request is returned as the parameter C<< '' >>.
+
=back
=head1 OTHER FUNCTIONS AND METHODS
I<$reqtype> is the request type (the value which will be passed to
C<check_nonpage> and C<need_add_hidden>. If you are supporting a new
-I<$reqtype> you shouuld coordinate with CGI::Auth::Flexible upstrea,
+I<$reqtype> you shouuld coordinate with CGI::Auth::Flexible upstream,
or other users, to assign a unique request type name.
This method may be called on an authreq or a verifier, in which case
C<< XMLHttpRequest >> returning data of some other kind. (Possibly
confidential for the user.)
-=back.
+=back
=head1 DIVERT SPEC
=item C<Params>
+Provided with diversion kinds which involve
+generating a redirection or indirection,
+perhaps via a login form.
+
The extra hidden form parameters (and the C<PATH_INFO>) which should
be set when the subsequent request bounces back from the client, in
the form used by C<url_with_query_params>.
We should redirect to our actual application, with the specified
parameters. (The user has just logged in.)
+=item C<STALE>
+
+The user is logged in but the incoming form submission looks like it
+was from a stale login session. Alternatively, it may have been
+generated by an attacker's cross-site-scripting attack.
+
+Naive applications should generate a small page with a form or link to
+our own main page without any parameters.
+
+A sophisticated application could infer from the submitted form
+parameters what the user was allegedly trying to do. We could then
+generate a fresh page showing what the intended action was, with a
+fresh form which (if the user confirm) would resubmit that action.
+B<Great care> must be taken to avoid relying on the sanity and
+coherence of the incoming form parameters. We B<MUST NOT> simply
+reproduce the incoming parameters in the new form. It is essential
+that the visual appearance of the generated form correctly shows to
+the user what the action is that will be taken if the form is
+submitted. If that action is dangerous, the form should not look like
+the kind of confirmation pages which the user is likely to simply
+click through without thinking.
+
=item C<MAINPAGEONLY>
We should generate our main page but B<ignoring all form parameters>
(Applications which set C<promise_check_mutate> do not see this divert
kind.)
+=back
+
+Applications should die if they are presented with a divert kind that
+they don't recognise.
+
=head1 SETTINGS
C<new_verifier> and C<new_request> each take a list of settings, as
function won't also be described in the section on the module's
functions.
-=over
-
=head2 GENERAL SETTINGS
+=over
+
=item C<dir>
The directory CGI::Auth::Generic should use for its data storage.
If you want users to be able to explicitly log out, you need to
provide a logout button, something like
-C<< <input type="submit" name="caf_logout" ...>>
+C<< <input type="submit" name="caf_logout" ... >>
The default is C<['caf_logout']>
The default is 1.
-=back
-
=item C<< get_url($cgi,$authreq) >>
Hook which returns the URL of this web application. By default, we
Returns the HTTP method as a string. The default is to call
C<< $cgi->request_method() >>.
-=back
-
=item C<< is_https($cgi,$authreq) >>
Returns a boolean indicating whether the request was over an encrypted
Some of CAF's HTML-generating functions need to invent form parameter
names. They will all start with this string. Default: C<caf__>.
+=back
+
=head2 SETTINGS FOR SOURCE CODE DOWNLOAD FACILITY
=over
+=item C<srcdump_needlogin>
+
+Boolean: do users need to log in to be able to download the source
+code for the whole application ? Default: 0.
+
=item C<srcdump_param_name>
Form parameter name used to indicate that this is a source download
xxx document @default_db_setup_statements
xxx bugs wrong default random on Linux
+
xxx bugs wrong default random on *BSD
+
xxx bugs keys not shared should be in db
+
xxx rename caf_assocsecret default cookie name
+
xxx mention relationship between login_timeout and cookies
~ian / cgi-auth-flexible.git / blobdiff