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package Koha::XSLT::Security; |
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# Copyright 2019 Prosentient Systems, Rijksmuseum |
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# |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it under the |
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# terms of the GNU General Public License as published by the Free Software |
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# Foundation; either version 3 of the License, or (at your option) any later |
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# version. |
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# |
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# Koha is distributed in the hope that it will be useful, but WITHOUT ANY |
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR |
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# A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License along |
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# with Koha; if not, write to the Free Software Foundation, Inc., |
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
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=head1 NAME |
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Koha::XSLT::Security - Add security features to Koha::XSLT::Base |
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=head1 SYNOPSIS |
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use Koha::XSLT::Security; |
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my $secu = Koha::XSLT::Security->new; |
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$secu->register_callbacks; |
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$secu->set_parser_options($parser); |
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=head1 DESCRIPTION |
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This object allows you to apply security options to Koha::XSLT::Base. |
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It looks for parser options in koha-conf.xml. |
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=cut |
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use Modern::Perl; |
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use Data::Dumper qw/Dumper/; |
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use XML::LibXSLT; |
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use C4::Context; |
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use base qw(Class::Accessor); |
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=head1 METHODS |
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=head2 new |
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Creates object, checks if koha-conf.xml contains additional configuration |
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options, and checks if XML::LibXSLT::Security is present. |
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=cut |
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sub new { |
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my ($class) = @_; |
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my $self = {}; |
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my $conf = C4::Context->config('koha_xslt_security'); |
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if( $conf && ref($conf) eq 'HASH' ) { |
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$self->{_options} = $conf; |
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} |
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my $security = eval { XML::LibXSLT::Security->new }; |
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if( $security ) { |
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$self->{_security_obj} = $security; |
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} else { |
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warn "No XML::LibXSLT::Security object: $@"; #TODO Move to about ? |
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} |
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return bless $self, $class; |
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} |
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=head2 register_callbacks |
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Register LibXSLT security callbacks |
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=cut |
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sub register_callbacks { |
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my $self = shift; |
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my $security = $self->{_security_obj}; |
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return if !$security; |
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$security->register_callback( read_file => sub { |
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warn "read_file called in XML::LibXSLT"; |
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#i.e. when using the exsl:document() element or document() function (to read a XML file) |
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my ($tctxt,$value) = @_; |
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return 0; |
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}); |
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$security->register_callback( write_file => sub { |
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warn "write_file called in XML::LibXSLT"; |
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#i.e. when using the exsl:document element (or document() function?) (to write an output file of many possible types) |
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#e.g. |
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#<exsl:document href="file:///tmp/breached.txt"> |
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# <xsl:text>breached!</xsl:text> |
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#</exsl:document> |
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my ($tctxt,$value) = @_; |
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return 0; |
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}); |
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$security->register_callback( read_net => sub { |
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warn "read_net called in XML::LibXSLT"; |
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#i.e. when using the document() function (to read XML from the network) |
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#e.g. <xsl:copy-of select="document('http://localhost')" /> |
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my ($tctxt,$value) = @_; |
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return 0; |
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}); |
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$security->register_callback( write_net => sub { |
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warn "write_net called in XML::LibXSLT"; |
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#NOTE: it's unknown how one would invoke this, but covering our bases anyway |
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my ($tctxt,$value) = @_; |
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return 0; |
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}); |
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} |
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=head2 set_callbacks |
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my $xslt = XML::LibXSLT->new; |
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$security->set_callbacks( $xslt ); |
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Apply registered callbacks to a specific xslt instance. |
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=cut |
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sub set_callbacks { |
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my ($self, $xslt) = @_; |
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my $security = $self->{_security_obj}; |
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return if !$security; |
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$xslt->security_callbacks( $security ); |
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} |
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=head2 set_parser_options |
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$security->set_parser_options($parser); |
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If koha-conf.xml includes koha_xslt_security options, set them. |
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We start with implementing expand_entities. |
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=cut |
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sub set_parser_options { |
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my ($self, $parser) = @_; |
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my $conf = $self->{_options}; |
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return if !$conf; |
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if( exists $conf->{expand_entities} && $conf->{expand_entities} eq '0' ) { |
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# we only disable expanding, if we find an explicit 0 |
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_set_option($parser, 'expand_entities', 0); |
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} |
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} |
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sub _set_option { |
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my ($parser, $option_name, $value) = @_; |
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if( $parser->option_exists($option_name) ) { |
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$parser->set_option($option_name, $value); |
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} |
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#TODO Should we warn if it does not exist? |
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} |
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=head1 AUTHOR |
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David Cook, Prosentient Systems |
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Marcel de Rooy, Rijksmuseum Netherlands |
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=cut |
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1; |