template toolkit output filtering lint tests
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NAME
    Template::Directive::XSSAudit - TT2 output filtering lint testing

SYNOPSIS
      use Template;
      use Template::Directive::XSSAudit;

      my $tt = Template->new({
          FACTORY => "Template::Directive::XSSAudit"
      });

      my $input = <<'END';
      Hello [% exploitable.goodness %] World!
      How would you like to [% play.it.safe | html %] today?
      END

      my $out  = '';
      $tt->process(\$input, {}, \$out) || die $tt->error();

      # output on STDOUT... via default on_error handler
      # see the documentation of on_error for explanation of the
      # output format of the default error handler
      #input file   NO_FILTERS  line:1    exploitable.goodness

DESCRIPTION
    This module will help you perform basic lint tests of your template
    toolkit files.

    It is intended to parse through all GET items, and make sure that at
    least one "good" filter is used to escape it.

    A callback may be provided so that the errors may be handled in a way
    that makes sense for the project at hand. See "on_error" for more
    details.

    There is another callback which can be provided named "on_filtered".
    This is triggered when a variable is successfully filtered. By default
    there is no implementation. See "on_filtered" for more details.

    Additionally, a list of filter names may be provided, instructing the
    module to require that certain filters be used for output escaping in
    the tests.

    Have a look at the t/*.t files that come with the distribution as they
    leverage the "on_error()" callback routine.

IMPORTANT NOTES ON SECURITY
    This tool is NOT a substitude for code and security reviews as it is NOT
    context aware. This means if you use a html filter in javascript context
    or css context or html attribute context, you would not be escaping
    things properly and this tool would not catch that.

    You also need to make sure that your "good" filters are actually doing
    their job and escaping things properly.

    All of this to say, don't let this give you a false sense of security.

EXPORTS
    None.

METHODS
    Template::Directive::XSSAudit->on_error ( [ coderef ] )
        This method is called on every variable involved in a template
        toolkit 'GET' which was not filtered properly.

        The callback will be executed in one of two cases:

         - The variable in question has NO output filtering
         - The variable is filtered but none of the filters 
           were found in the C<good_filter> list.

        A default implementation is provided which will simply "warn" any
        problems which are found with the following information (tab
        delimited):

          <file_name> <error_type> line:<line_no> <filters used csv>

        If you call this method without a subroutine reference, it will
        simply return you the current implementation.

        If you provide your own callback, it will be passed one parameter
        which is a hash reference containing the following keys.

        variable_name
            This is a string represending the variable name which was found
            to be incorrectly escaped.

        filtered_by
            This will contain an array reference containing the names of the
            filters which were applied to the variable name.

            If there are entries in this list, it means that no filter in
            the good filter list was found to apply to the variable. See
            "good_filter" for more information.

            In the case of variables with no filters, this will be an empty
            array reference.

        file_name
            The line number in the template file where the problem occurred.

            This is parsed out as best as can be done but it may come back
            as an empty string in many cases. It is a convenience item and
            should not be relied on for any sort of automation.

        file_line
            The line number in the template file where the problem occurred.

            This is parsed out as best as can be done but it may come back
            as an empty string in many cases. It is a convenience item and
            should not be relied on for any sort of automation.

    Template::Directive::XSSAudit->on_filtered ( [ coderef ] )
        This method is called on every variable involved in a template
        toolkit 'GET' which was filtered satisfactorily.

        By default, no implementation is given so if you want this to do
        anything, you'll have to provide a coderef yourself.

        The callback and function works just like "on_error" so see the
        documentation for that method for more details.

    Template::Directive::XSSAudit->good_filters ( [ arrayref ] )
        This method will return the current list of "good" filters to you as
        an array reference. eg.

          [ 'html', 'uri' ]

        If you pass an array reference of strings, it will also set the list
        of good filters. The defaults are simply 'html' and 'uri' but I will
        be adding more int the future.

SEE ALSO
    Template <http://github.com/captin411/template-directive-xssaudit/>
    <http://www.owasp.org/index.php/Category:OWASP_Encoding_Project/>
    <http://ha.ckers.org/xss.html>

BUGS
    Please report bugs using the CPAN Request Tracker at
    <http://rt.cpan.org/>

AUTHOR
    David Bartle <dbartle@mediatemple.net>

    This work was sponsored by my employer, (mt) Media Temple, Inc.

COPYRIGHT
    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    The full text of the license can be found in the LICENSE file included
    with this module.