trusty (3) ReverseProxy::FormFiller.3pm.gz
NAME
ReverseProxy::FormFiller - Let Apache fill and submit any html form in place of the user
VERSION
Version 0.2
SYNOPSIS
ReverseProxy::FormFiller makes an Apache server, positioned as a frontal server or as a reverse-proxy,
fill and (possibly) submit html forms in place of users.
This is particularly intended for authentication forms, if you want users to be authenticated with some
account, but if you don't want them to know and type any password. But it also works with any html POST
form.
ReverseProxy::FormFiller is based on Apache2 mod_perl filters. So, you have to enable mod_perl.
Basic Example
Assume you want all users requesting auth.example.com to be authenticated as "jdoe", but you don't want
to publish jdoe's password. If auth.example.com's authentication form is located at
http://auth.example.com/login.php and looks like
<form id="authForm" method="POST" action="/login/">
<div>login: <input type="text" name="login"></div>
<div>password: <input type="password" name="password"></div>
<div><input type="submit" value="Log in"></div>
</form>
create an Apache virtualhost called myauth.example.com, looking like :
<VirtualHost *>
ServerName myauth.example.com
PerlModule ReverseProxy::FormFiller
PerlSetVar FormFillerParamFile "/etc/apache2/FormFiller/example"
ProxyPass / http://auth.example.com/
ProxyPassReverse / http://auth.example.com/
<Location /login.php>
RequestHeader unset Accept-Encoding
Header unset Content-Length
PerlOutputFilterHandler ReverseProxy::FormFiller::output
</Location>
<Location /login/>
PerlInputFilterHandler ReverseProxy::FormFiller::input
</Location>
</VirtualHost>
and create a ReverseProxy::FormFiller config file at /etc/apache2/FormFiller/example, looking like
form => '#authForm',
submit => "true",
publicFormData => {
login => "jdoe",
password => "fake",
},
secretFormData => {
password => "secret",
},
Elaborate example
Assume you want some people to be authenticated as "user", and some other as "admin".
Besides, assume just submit form does not work, but it is necessary to click on the button, since it will
execute a javascript function.
Finally, assume jQuery is not loaded by the web page displaying the form.
/etc/apache2/FormFiller/example will look like
jQueryUrl => 'http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js',
form => '#authForm',
submit => "button[type=submit]",
publicFormData => {
login => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin" : "user"',
password => "fake",
},
secretFormData => {
password => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin-secret" : "user-secret"',
},
Screwy example
Assume you have two authentication forms in the same page, one for the morning and another one for the
afternoon :
/etc/apache2/FormFiller/example will look like
form => '(localtime)[2] >= 12 ? "#morningForm" : "#afternoonForm"',
submit => "false",
publicFormData => {
login => "jdoe", # so, user believe he'll be authenticated as "jdoe"
password => "fake",
},
secretFormData => {
# but actually, he'll be authenticated as "admin" or as "user"
login => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin" : "user"',
password => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin-secret" : "user-secret"',
},
Details of Apache config
Load Module
This is done by
PerlModule ReverseProxy::FormFiller
This directive has to appear once in Apache config. It can be set in server config or in a <VirtualHost>
container.
Set config parameters
This is done by
PerlSetVar FormFillerParamFile "/etc/apache2/FormFiller/example"
This directive can be set in server config or in a any container directive (as a <VirtualHost> container,
a <Location> container or a <Directory> container). It is applied only to requests matching the
corresponding container directive.
This directive can be set several times, so a single server can manage several forms (typically, on
different virtualhosts, but you can also manage several forms in the same virtualhost).
Filter response body
When Apache has received the response from the remote server (if Apache is used as a reverse-proxy) or
from the backend server (if used as a frontend), it rewrites html so as to fill the form and possibly
submitting it or clicking on a button.
Actually, this is done not by directly overwriting the form, but by including some javascript filling and
submitting the form.
This is done by the directive
PerlOutputFilterHandler ReverseProxy::FormFiller::output
Besides, ReverseProxy::FormFiller::output can not (or not yet) read zipped contents, so HTTP request
headers "Content-encoding" have to be removed. This is done by the directive
RequestHeader unset Accept-Encoding
And ReverseProxy::FormFiller::output can not (or not yet) set Content-Length response header to the
modified response body's length. So, remove Content-Length response header to avoid some bugs:
Header unset Content-Length
For performances, it is better to handle only html pages containing the aimed form. So, you should place
these directives in a container directive matching the form URL (as a <Location> directive), so as not to
filter any html content.
Filter request body
When Apache receives a POST request from a client, it rewrites request POST body, replacing empty or fake
data with secret data. This is done by the directive
PerlInputFilterHandler ReverseProxy::FormFiller::input
For performances, it is better to handle only requests to the form "action" URL. So, you should place
this directive in a container directive matching this URL (as a <Location> directive), so as not to
filter any request.
ReverseProxy::FormFiller config parameters
ReverseProxy::FormFiller config file looks similar to a .ini file, but it is not. Actually it is simply a
hash content. So, don't forget commas ! In case of syntax error, you'll have a message "<config file>
content doesn't seem to be a valid perl hash" in Apache error logs.
jQueryUrl
URL to load jQuery, since ReverseProxy::FormFiller response filter relies on jQuery (any version >= 1.0)
Optional: if empty or not defined, jQuery is supposed to be already loaded in the web page
form
jQuery selector to the form to fill. For example :
form => "form#authForm",
or
form => "form:last",
Optional: if empty or not defined, first form in web page will be filled - i.e.,
form => "form:first",
This field may rely on perl functions and Apache environment vars, e.g
form => '(localtime)[2] >= 12 ? "#morningForm" : "#afternoonForm"',
or
form => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "#adminForm" : "#userForm"',
submit
To enable form autosubmit, or to automatically click on a button.
It may be "true" (autosubmit enabled), "false" (autosubmit disabled), or a jQuery selector to the button
to click on (this is sometimes useful, when clicking runs a javasript function). It also may rely on perl
functions and Apache environment vars (as same as "form" parameter).
Optional: if empty or not defined, autosubmit is disabled - that is, default value is "false".
For example,
submit => "true",
or
submit => 'button#login',
publicFormData
Form fields to fill in html form : these data will be seen by user.
Additionnaly, these fields will be controled in POST request when the form will be submitted, to prevent
malicious users to change any value.
As same as "submit" and "form" parameters, field values can rely on perl functions and Apache environment
vars.
For example,
publicFormData => {
company => "SnakeOilsInc",
user => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin" : "user"',
password => "hidden"
},
Note that these data are filled through jQuery method '.val()', so it works only with text inputs,
password inputs, select tags and textarea, but not with checkbox and radio buttons.
But all inputs
secretFormData
Form fields to fill in request body, in addition or in overload to publicFormData. The main with between
publicFormData is that these data will not be filled in the html form, so users can't see them.
Field values can rely on perl functions and Apache environment vars.
secretFormData => {
password => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin-secret" : "user-secret"',
},
AUTHOR
FX Deltombe, "<fxdeltombe at gmail.com>"
BUGS
Please report any bugs or feature requests to "bug-reverseproxy-formfiller at rt.cpan.org", or through
the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ReverseProxy-FormFiller
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ReverseProxy-FormFiller>. I will be notified, and then
you'll automatically be notified of progress on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc ReverseProxy::FormFiller
You can also look for information at:
• RT: CPAN's request tracker
http://rt.cpan.org/NoAuth/Bugs.html?Dist=ReverseProxy-FormFiller
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=ReverseProxy-FormFiller>
• AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/ReverseProxy-FormFiller <http://annocpan.org/dist/ReverseProxy-FormFiller>
• CPAN Ratings
http://cpanratings.perl.org/d/ReverseProxy-FormFiller <http://cpanratings.perl.org/d/ReverseProxy-
FormFiller>
• Search CPAN
http://search.cpan.org/dist/ReverseProxy-FormFiller/ <http://search.cpan.org/dist/ReverseProxy-
FormFiller/>
ACKNOWLEDGEMENTS
LICENSE AND COPYRIGHT
Copyright 2013 FX Deltombe.
This program is free software; you can redistribute it and/or modify it under the terms of either: the
GNU General Public License as published by the Free Software Foundation; or the Artistic License.
See http://dev.perl.org/licenses/ for more information.