158 lines
4.0 KiB
Perl
158 lines
4.0 KiB
Perl
package Email::SpoofingDemo::DKIM;
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use strict;
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use warnings;
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use v5.10;
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use utf8;
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use Exporter 'import';
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our @EXPORT_OK = qw(read_signing_table read_key_table
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write_signing_table write_key_table
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generate_dkim_key);
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sub generate_dkim_key {
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my ($domain, $selector, $key_size, $key_table_name, $key_dir, $signing_table_name) = @_;
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die if $domain =~ /\.\./;
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my $key_domain_dir = "$key_dir/$domain";
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# Generate the key
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system("mkdir", "-p", $key_domain_dir);
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system("opendkim-genkey",
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"-D", $key_domain_dir,
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"-d", $domain,
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"-s", $selector,
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"-b", $key_size);
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system("chown", "-R", "opendkim", $key_domain_dir);
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# Read in the public key
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my $public_key_file = "$key_domain_dir/$selector.txt";
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open(my $fh, '<', $public_key_file) or die "$key_domain_dir: $!";
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my $data = eval {
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local $/ = undef;
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my $raw_record = <$fh>;
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my ($owner, $class, $type, $data) = split(" ", $raw_record, 4);
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$data =~ s/\s*;.*$//;
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return $data;
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};
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close($fh);
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# Update key table
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my $key_table = read_key_table($key_table_name);
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push @{$key_table->{$domain}}, $selector;
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write_key_table($key_table_name, $key_dir, $key_table);
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# Update signing table if it’s the first key for the domain
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my $signing_table = read_signing_table($signing_table_name);
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if (not exists $signing_table->{$domain}) {
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$signing_table->{$domain} = $selector;
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write_signing_table($signing_table_name, $signing_table);
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}
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# Done!
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reload_opendkim();
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return $data;
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}
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sub read_signing_table {
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my ($filename) = @_;
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my %sign_table;
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open(my $fh, '<', $filename) or die "$filename: $!";
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while (<$fh>) {
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chomp;
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s/#.*$//;
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next if /^\s*$/;
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my ($domain_or_email, $key_id) = split(" ", $_, 2);
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my $domain = ($domain_or_email =~ s/^.*@//r);
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my $selector = ($key_id =~ s/\._domainkey.$domain$//r);
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$sign_table{$domain} = $selector;
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}
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close($fh);
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return \%sign_table;
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}
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sub write_signing_table {
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my ($filename, $contents) = @_;
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open(my $fh, '>', $filename) or die "$filename: $!";
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binmode($fh, ':utf8');
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print $fh <<'EOF';
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##
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## FORMAT DE LA TABLE
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##
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## <domaine ou adresse mail> <identifiant>
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##
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## L’adresse mail peut être un wildcard (ex. *@expediteur.example).
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##
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EOF
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for my $domain (sort keys %$contents) {
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my $selector = $contents->{$domain};
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my $key_id = "$selector._domainkey.$domain";
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printf $fh "%-30s %s\n", $domain, $key_id;
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}
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close($fh);
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}
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sub read_key_table {
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my ($filename) = @_;
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# We only care about the list of keys that exist for a given domain.
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# The rest of the data can be deduced from that mapping.
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my %key_table;
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open(my $fh, '<', $filename) or die "$filename: $!\n";
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while (<$fh>) {
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chomp;
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s/#.*$//;
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next if /^\s*$/;
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my ($key_id, $key_spec) = split(" ", $_, 2);
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my ($domain, $selector, $key_location) = split(":", $key_spec, 3);
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push @{$key_table{$domain}}, $selector;
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}
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return \%key_table;
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}
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sub write_key_table {
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my ($filename, $key_dir, $contents) = @_;
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open(my $fh, '>', $filename) or die "$filename: $!\n";
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binmode($fh, ':utf8');
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print $fh <<EOF;
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##
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## FORMAT DE LA TABLE
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##
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## <identifiant> <domaine>:<sélecteur>:<fichier>
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##
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EOF
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for my $domain (sort keys %$contents) {
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for my $selector (@{$contents->{$domain}}) {
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my $key_id = "$selector._domainkey.$domain";
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my $key_file = "$key_dir/$domain/$selector.private";
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printf $fh "%-30s %s:%s:%s\n", $key_id, $domain, $selector, $key_file;
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}
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}
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close($fh);
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}
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sub reload_opendkim {
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system(qw(killall -USR1 opendkim));
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return (($? >> 8) == 0);
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}
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1;
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