cryptobox/cryptobox

#!/usr/bin/env bash

##############################################################
#                                                            #
#  CryptoBox                                                 #
#                                                            #
#  A script that wraps cryptsetup, mkfs and losetup to make  #
#  it easy to create, mount and unmount encrypted image      #
#  files using LUKS.                                         #
#                                                            #
##############################################################

NAME=`echo $0 | grep -o -e "[^\/]*$"`

# Check for root
[[ "$UID" -ne 0 ]] && (echo -e "Error: Please run this script with root permissions\n"; exit 1)

# Check dependencies
[[ `type -P dd` ]] || (echo "Error: The 'dd' program is missing"; exit 1)
[[ `type -P losetup` ]] || (echo "Error: The 'losetup' program is missing"; exit 1)
[[ `type -P cryptsetup` ]] || (echo "Error: The 'cryptsetup' program is missing"; exit 1)
[[ `type -P mkfs` ]] || (echo "Error: The 'mkfs' program is missing"; exit 1)

# Load modules if they aren't present
[[ `lsmod | grep loop` ]] || echo "loading 'loop' module"; modprobe loop || (echo "Error: failed to load 'loop' module"; exit 1)
[[ `lsmod | grep dm_mod` ]] || echo "loading 'dm_mod' module"; modprobe dm_mod || (echo "Error: failed to load 'dm_mod' module"; exit 1)

function usage {
    echo -e "${NAME}: create and mount encrypted images\n"
    echo "Usage: ${NAME} option arguments"
    echo -e "\tc (create) -> $NAME c filename.img filesystem size-in-mb"
    echo -e "\tm (mount) -> $NAME m filename.img /mount/point"
    echo -e "\tu (umount) -> $NAME u /mount/point"
}

if [ -z "$1" ]; then
    usage
    exit 1
elif [ ! "$1" = "c" -a ! "$1" = "m" -a ! "$1" = "u" ]; then
    echo "syntax error"
    usage
    exit 1
fi

case "$1" in
    "c")
        if [ -z "$2" -o -z "$3" -o -z "$4" ]; then
            echo "syntax error"
            usage
            exit 1
        fi
        if [ -f "$2" ]; then
            echo "error: $2 already exists"
            exit 1
        fi
        LOOPDEV=`losetup -f`
        CONTAINER=`echo "$2" | sed s/"[^\/]*\/"//g | sed s/"\.".*$//g`
        dd bs=1M count="$4" if=/dev/urandom of="$2"
        losetup $LOOPDEV "$2"
        cryptsetup -c aes-xts-plain -y -s 512 luksFormat $LOOPDEV
        cryptsetup luksOpen $LOOPDEV $CONTAINER
        mkfs -t "$3" /dev/mapper/$CONTAINER || echo "error: mkfs failed for filesystem type: $3"
        cryptsetup luksClose $CONTAINER
        losetup -d $LOOPDEV
        ;;
    "m")
        if [ -z "$2" -o -z "$3" ]; then echo -e "Error: syntax\n"; usage; exit 1; fi
        [[ ! -f "$2" ]] && (echo "Error: $2 does not exist"; exit 1)
        [[ -d "$3" ]] || (echo "Error: $3 does not exist"; exit 1)
        LOOPDEV=$(losetup -f)
        CONTAINER=$(echo $LOOPDEV | sed s/"[^\/]*\/"//g | sed s/"\.".*$//g)
        losetup $LOOPDEV "$2"
        cryptsetup luksOpen $LOOPDEV $CONTAINER
        mount /dev/mapper/$CONTAINER "$3"
        ;;
    "u")
        if [ -z "$2" ]; then
            echo "syntax error"
            usage
            exit 1
        fi
        MOUNT=`mount | grep $(echo "$2" | sed s/"\/"$//)`
        if [ -z "$MOUNT" ]; then
            echo "error: $2 is not mounted"
            exit 1
        fi
        LOOPDEV=`echo $MOUNT | sed s/\ .*//g | sed s/"\/mapper"//`
        CONTAINER=`echo $LOOPDEV | sed s/"[^\/]*\/"//g | sed s/"\.".*$//g`
        umount "$2"
        cryptsetup luksClose $CONTAINER
        losetup -d $LOOPDEV
        ;;
    generic)
        usage
        ;;
esac