cannot chdir to /root from /tmp/msg-1487427712-24006-0: Keine Berechtigung, aborting. at /usr/share/perl5/MIME/Parser/Filer.pm line 715.

%sudo   ALL = NOPASSWD: ALL

    # Example procmailrc rule
    :0
    * ^To: <username>@<domain>.<tld>
    | sudo /home/<username>/bin/decrypt.pl

#!/usr/bin/perl -w

use Mail::GPG;
use MIME::Parser;
use Email::Sender::Simple qw(sendmail);
use Email::Simple;
use Email::Simple::Creator;
use strict;
#no strict 'refs';
my $passphrase = 'XXX';
my @lines;
my $tmpdir = '/tmp';

########
# Main #
########

my $stdin = &stdin();
my $unencrypted_body = &parse_email($stdin);
mail_it( $$unencrypted_body );
if ($unencrypted_body) {

    foreach ($$unencrypted_body) {
        chomp $_;
        push( @lines, $_ );
        print "$_\n"; ## Debugging
    }
}


###############
# Subroutines #
###############

sub stdin {
    #Process stdin
    my $stdin = '';

   while(<ARGV>){
   $stdin .= $_;
   }

   if ($stdin eq '') {
        die ("Error: stdin appears to have no content.");
   }

    return $stdin;
}

sub parse_email {

    my $stdin = shift @_;
    my $decoded_body_sref;
    my $entity;

    #Create new MIME Parser obj
    my $parser = MIME::Parser->new;

    #Configure MIME Parser
    $parser->decode_bodies(0);
    $parser->output_under($tmpdir);

    #Parse the email from stdin
    eval { $entity = $parser->parse_data($stdin) };

    # See Mail::GPG for reasoning
    # http://search.cpan.org/~jred/Mail-GPG-1.0.7/lib/Mail/GPG.pm#METHODS_FOR_PARSING,_DECRYPTION_AND_VERIFICATION
    if ( $entity->effective_type ne 'multipart/signed' and
         $entity->effective_type ne 'multipart/encrypted' ) {

            #delete tmp files
            $parser->filer->purge;

            #enable docode_bodies
            $parser->decode_bodies(1);

            #Parse the email from stdin
            eval { $entity = $parser->parse_data($stdin) };

            #decrypt
            eval { $decoded_body_sref = &decode($entity) };
            if ($@) {
                warn ("Error: $@");
            }

            #delete tmp files
            $parser->filer->purge;
    }
    else {

        #decrypt
        eval { $decoded_body_sref = &decode($entity) };
        if ($@) {
            warn ("Error $@");
        }

        #delete tmp files
        $parser->filer->purge;

    }

    return $decoded_body_sref;
}

sub decode {

    my $entity = shift @_;

    #Create new Mail GPG obj
    my $mg = Mail::GPG->new;

    #Decrypt the email from stdin
    my ($decrypted_entity, $result) = $mg->decrypt (
        entity     => $entity,
        passphrase => $passphrase
    );

    #Get a reference to the decoded message body
    my $decoded_body_sref = $result->get_gpg_stdout;
    return $decoded_body_sref;
}
# ***NEW*** own subroutine for mail sending
sub mail_it {
    my $mailtext = shift;
    my $to      = 'chris@localhost';
    my $from    = 'root@localhost';
    my $subject = 'Test Email from decrypt.pl';

my $email = Email::Simple->create(
  header => [
    To      => $to,
    From    => $from,
    Subject => $subject,
  ],
  body => $mailtext,
);
sendmail($email);
}