Encrypts old mails for Dovecot mail-crypt-plugin

encrypt_maildir.sh

#!/usr/local/bin/bash
#
# Encrypt/Decrypt/Check emails with Dovecot's mail-crpyt-plugin
# This script will encrypt/decrypt emails in-place
# Please read: https://wiki.dovecot.org/Design/Dcrypt and https://wiki2.dovecot.org/Plugins/MailCrypt
#
# Update variables with your keys and patch otherwise you will loose data!
#
# I take no responsibility for data loos this script may cause
#
# IMPORTANT:
# BEFORE USE ADD THIS MAGIC(5) TO YOUR LOCAL MAGIC DATABASE:
# 0      string          CRYPTED             MailCrypt

count=0
processed=0
tempfile=$(mktemp)

uid=_vmail
gid=_vmail
maildir_path=/home/mailstore/maildir
private_key_path=/etc/dovecot/crypt/master.key
public_key_path=/etc/dovecot/crypt/master.pub

if [ "$1" == "" ]; then
    echo "Missing user folder"
    exit 1
  elif [ "$2" == "" ]; then
    echo "Missing folder name (ex. .Archives)"
    exit 1
fi

case $3 in
  encrypt) mode=encrypt; text_d="Encrypting"
  ;;
  decrypt) mode=decrypt; text_d="Decrypting"
  ;;
  check) mode=check; text_d="Checking"
  ;;
  *)  echo "Unknown mode. Modes: [encrypt|decrypt|check]"; exit 1
esac

_encrypt(){
  touch -r "$mailmessage" $tempfile
  doveadm fs put crypt private_key_path=$private_key_path:public_key_path=$public_key_path:posix:prefix=$maildir_path/$userdir/Maildir/"$box"/ $message $message
  touch -r $tempfile "$mailmessage"
  chown $uid:$gid "$mailmessage"
}

_decrypt(){
  touch -r "$mailmessage" $tempfile
  doveadm fs get crypt private_key_path=$private_key_path:public_key_path=$public_key_path:posix:prefix=$maildir_path/$userdir/Maildir/"$box"/ $message > .tempdecrypted
  mv .tempdecrypted "$message"
  touch -r $tempfile "$mailmessage"
  chmod 0600 "$message"
  chown $uid:$gid "$mailmessage"
}

# special case for cur
if [ "$2" == "cur" ];then
    box="cur"
  else
    box="$2/cur"
fi

userdir="$1"

if [ ! -d $maildir_path/$userdir/Maildir/"$box"/ ];then
  echo "Folder do not exist: $maildir_path/$userdir/Maildir/$box/"
  exit 1
fi

totalfiles=$(find $maildir_path/$userdir/Maildir/"$box"/ -type f | wc -l | xargs)
echo
echo "$text_d mails in $maildir_path/$userdir/Maildir/$box/"
echo "Found $totalfiles, processing..."
echo ". plain text" 
echo "* encrypted "
echo "< encryptinge"
echo "> decrypting"
echo

# operate in context
cd $maildir_path/$userdir/Maildir/"$box"/
for mailmessage in $maildir_path/$userdir/Maildir/"$box"/*; do
  message=$(basename "$mailmessage")
  testfiletype=$(file -b "$mailmessage")
  if [ "$testfiletype" != "MailCrypt" ]  ;then
      echo -n "."
      if [ "$mode" == "encrypt" ];then
        _encrypt
        echo -n "<"
      fi
    else
      echo -n "*"
      if [ "$mode" == "decrypt" ];then
        _decrypt
        echo -n ">"
      fi
  fi
  count=$(($count + 1))
  processed=$(($processed + 1))
  if [ $count == 10 ];then
    echo -n "$processed/$totalfiles"
    echo -e
    count=0
  fi


done
rm -f $tempfile

echo -e "\n\nDone"