#!/usr/bin/perl
# Copyright 2005-2006 Messiah College. All rights reserved.
# Jason Long <jlong@messiah.edu>
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.
use strict;
use warnings;
package Mail::DKIM::Canonicalization::DkCommon;
use base "Mail::DKIM::Canonicalization::Base";
use Carp;
sub init
{
my $self = shift;
$self->SUPER::init;
$self->{myheaders} = [];
}
# similar to code in DkimCommon.pm
sub add_header
{
my $self = shift;
my ($line) = @_;
#croak "header parse error \"$line\"" unless ($line =~ /:/);
$line =~ s/\015\012\z//s;
push @{$self->{myheaders}},
$self->canonicalize_header($line . "\015\012");
}
sub finish_header
{
my $self = shift;
# RFC4870, 3.3:
# h = A colon-separated list of header field names that identify the
# headers presented to the signing algorithm. If present, the
# value MUST contain the complete list of headers in the order
# presented to the signing algorithm.
#
# In the presence of duplicate headers, a signer may include
# duplicate entries in the list of headers in this tag. If a
# header is included in this list, a verifier must include all
# occurrences of that header, subsequent to the "DomainKey-
# Signature:" header in the verification.
#
# RFC4870, 3.4.2.1:
# * Each line of the email is presented to the signing algorithm in
# the order it occurs in the complete email, from the first line of
# the headers to the last line of the body.
# * If the "h" tag is used, only those header lines (and their
# continuation lines if any) added to the "h" tag list are included.
# check if signature specifies a list of headers
my @sig_header_names = $self->{Signature}->headerlist;
my @sig_headers;
if (@sig_header_names)
{
# - first, group all header fields with the same name together
# (using a hash of arrays)
my %heads;
foreach my $line (@{$self->{myheaders}})
{
next unless $line =~ /^([^\s:]+)\s*:/;
my $field_name = lc $1;
$heads{$field_name} ||= [];
push @{$heads{$field_name}}, $line;
}
# - second, count how many times each header field name appears
# in the h= tag
my %counts;
foreach my $field_name (@sig_header_names)
{
$heads{lc $field_name} ||= [];
$counts{lc $field_name}++;
}
# - finally, working backwards through the h= tag,
# collect the headers we will be signing (last to first).
# Normally, one occurrence of a name in the h= tag
# correlates to one occurrence of that header being presented
# to canonicalization, but if (working backwards) we are
# at the first occurrence of that name, and there are
# multiple headers of that name, then put them all in.
#
while (my $field_name = pop @sig_header_names)
{
$counts{lc $field_name}--;
if ($counts{lc $field_name} > 0)
{
# this field is named more than once in the h= tag,
# so only take the last occuring of that header
my $line = pop @{$heads{lc $field_name}};
unshift @sig_headers, $line if defined $line;
}
else
{
unshift @sig_headers, @{$heads{lc $field_name}};
$heads{lc $field_name} = [];
}
}
}
else
{
@sig_headers = @{$self->{myheaders}};
}
# iterate through each header, in the order determined above
foreach my $line (@sig_headers)
{
if ($line =~ /^(from|sender)\s*:(.*)$/i)
{
my $field = $1;
my $content = $2;
$self->{interesting_header}->{lc $field} = $content;
}
$self->output($line);
}
$self->output($self->canonicalize_body("\015\012"));
}
sub add_body
{
my $self = shift;
my ($multiline) = @_;
$self->output($self->canonicalize_body($multiline));
}
sub finish_body
{
}
sub finish_message
{
}
1;
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