#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# Generates an email client cert for use with IMAP clients

# See:
#   http://strange.systems/certificate-based-auth-with-dovecot-sendmail
#   http://help.fabasoftfolio.com/index.php?topic=doc/Installation-and-Configuration-of-Fabasoft-Folio-IMAP-Service/client-certificate-authentication.htm

# License
# =======
#
# Copyright (C) 2015 Bob Mottram <bob@robotics.uk.to>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

USERNAME=
COUNTRY_CODE="US"
AREA="Free Speech Zone"
LOCATION="Freedomville"
ORGANISATION="Freedombone"
UNIT="Freedombone Unit"
EXTENSIONS=""

function show_help {
    echo ''
    echo 'freedombone-clientcert -u [username]'
    echo ''
    echo 'Creates email certificates for use with IMAP clients'
    echo ''
    echo '     --help                  Show help'
    echo '  -u --username [name]       Username'
    echo ''
    exit 0
}

while [[ $# > 1 ]]
do
key="$1"

case $key in
    --help)
    show_help
    ;;
    -u|--username)
    shift
    USERNAME="$1"
    ;;
    *)
    # unknown option
    ;;
esac
shift
done

if [ ! $USERNAME ]; then
    echo 'No username specified'
    exit 5748
fi

if [ ! -d /home/$USERNAME ]; then
    echo "User $USERNAME not found"
    exit 76239
fi

if [ -d /home/$USERNAME/emailcert ]; then
    echo 'Client certs were already for created'
    exit 2953
fi

if [ ! -f /etc/dovecot/passwd-file ]; then
    touch /etc/dovecot/passwd-file
fi

# Add a user password
if ! grep -q "$USERNAME:{plain}" /etc/dovecot/passwd-file; then
  echo "$USERNAME:{plain}::::::nopassword" >> /etc/dovecot/passwd-file
fi

chmod 600 /etc/dovecot/passwd-file

# create a user cert
freedombone-addcert -h $USERNAME --nodh ""

if [ ! -f /etc/ssl/private/$USERNAME.key ]; then
    echo 'User certificates were not created'
    rm -rf /home/$USERNAME/emailcert
    exit 74835
fi

# create a certificate request
openssl req -new -sha256 -subj \
        "/O=$ORGANISATION/OU=$UNIT/C=$COUNTRY_CODE/ST=$AREA/L=$LOCATION/CN=$USERNAME" \
        -key /etc/ssl/private/$USERNAME.key \
        -out /etc/ssl/requests/$USERNAME.csr

if [ ! -f /etc/ssl/requests/$USERNAME.csr ]; then
    echo 'Certificate request was not created'
    rm -rf /home/$USERNAME/emailcert
    exit 83520
fi

# sign the certificate request
cd /etc/ssl
openssl ca -config /etc/ssl/dovecot-ca.cnf \
        -in /etc/ssl/requests/$USERNAME.csr \
        -out /etc/ssl/certs/$USERNAME.cer

if [ ! -f /etc/ssl/certs/$USERNAME.cer ]; then
    echo 'Authentication certificate was not created'
    rm -rf /home/$USERNAME/emailcert
    exit 343569
fi

# move the cert to the user's home
mkdir /home/$USERNAME/emailcert
mv /etc/ssl/certs/$USERNAME.cer /home/$USERNAME/emailcert
cp /etc/ssl/certs/dovecot-ca.crt /home/$USERNAME/emailcert
mv /etc/ssl/private/$USERNAME.key /home/$USERNAME/emailcert
mv /etc/ssl/certs/$USERNAME.crt /home/$USERNAME/emailcert
openssl pkcs12 -export -in /home/$USERNAME/emailcert/$USERNAME.cer \
        -out /home/$USERNAME/emailcert/$USERNAME.p12 \
        -inkey /home/$USERNAME/emailcert/$USERNAME.key \
        -certfile /home/$USERNAME/emailcert/dovecot-ca.crt \
        -password pass:""

# make an install script
echo '#!/bin/bash' > /home/$USERNAME/emailcert/install.sh
echo "sudo mv $USERNAME.crt /etc/ssl/certs" >> \
     /home/$USERNAME/emailcert/install.sh
echo "sudo mv $USERNAME.key /etc/ssl/private" >> \
     /home/$USERNAME/emailcert/install.sh
echo 'exit 0' >> /home/$USERNAME/emailcert/install.sh

# set permissions for the user
chmod -R 755 /home/$USERNAME/emailcert
chown -R $USERNAME:$USERNAME /home/$USERNAME/emailcert
chmod +x /home/$USERNAME/emailcert/install.sh

shred -zu /etc/ssl/requests/$USERNAME.csr

echo 'Email authentication certificate created. You can obtain it on the client with:'
echo ''
echo "      scp -P 2222 -r $USERNAME@$HOSTNAME:/home/$USERNAME/emailcert ~/"
echo ''

exit 0