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

function errorquit {
    echo -e "Error: $1"
    [[ "$1" = "syntax" ]] && (echo; usage)
    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"
}

# Check for root
[[ "$UID" -ne 0 ]] && errorquit "run with root permission\n"

# Check dependencies
[[ `type -P dd` ]] || errorquit "Error: The 'dd' program is missing"
[[ `type -P losetup` ]] || errorquit "Error: The 'losetup' program is missing"
[[ `type -P cryptsetup` ]] || errorquit "Error: The 'cryptsetup' program is missing"
[[ `type -P mkfs` ]] || errorquit "Error: The 'mkfs' program is missing"

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

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

case "$1" in
    c)
        if [ -z "$2" -o -z "$3" -o -z "$4" ]; then errorquit "syntax"; fi
        [[ -f "$2" ]] && errorquit "$2 already exists"
        LOOPDEV=`losetup -f`
        CONTAINER=`echo "$2" | sed s/"[^\/]*\/"//g | sed s/"\.".*$//g`
        dd bs=1M count="$4" if=/dev/urandom of="$2" || errorquit "couldn't create create image file"
        losetup "$LOOPDEV" "$2" || errorquit "couldn't setup loop device (${LOOPDEV})"
        cryptsetup -c aes-xts-plain -y -s 512 luksFormat "$LOOPDEV" || errorquit "couldn't encrypt image file"
        cryptsetup luksOpen "$LOOPDEV" "$CONTAINER" || errorquit "couldn't decrypt $CONTAINER"
        mkfs -t "$3" "/dev/mapper/${CONTAINER}" || errorquit "mkfs failed for filesystem type: $3"
        cryptsetup luksClose "$CONTAINER" || errorquit "couldn't close encryption for $CONTAINER"
        sleep 1
        losetup -d "$LOOPDEV" || errorquit "couldn't close loop device (${LOOPDEV})"
        ;;
    m)
        if [ -z "$2" -o -z "$3" ]; then errorquit "syntax"; fi
        [[ ! -f "$2" ]] && errorquit "$2 does not exist"
        [[ -d "$3" ]] || errorquit "$3 does not exist"
        LOOPDEV=$(losetup -f)
        CONTAINER=$(echo "$LOOPDEV" | sed s/"[^\/]*\/"//g | sed s/"\.".*$//g)
        losetup "$LOOPDEV" "$2" || errorquit "couldn't setup loop device (${LOOPDEV})"
        cryptsetup luksOpen "$LOOPDEV" "$CONTAINER" || errorquit "couldn't decrypt $CONTAINER"
        mount "/dev/mapper/${CONTAINER}" "$3" || errorquit "couldn't mount /dev/mapper/${CONTAINER} on $3"
        ;;
    u)
        if [ -z "$2" ]; then errorquit "syntax"; fi
        MOUNT=`mount | grep $(echo "$2" | sed s/"\/"$//)`
        [[ -z "$MOUNT" ]] && errorquit "$2 is not mounted"
        LOOPDEV=`echo "$MOUNT" | sed s/\ .*//g | sed s/"\/mapper"//`
        CONTAINER=`echo "$LOOPDEV" | sed s/"[^\/]*\/"//g | sed s/"\.".*$//g`
        umount "$2" || errorquit "Couldn't unmount $2"
        cryptsetup luksClose "$CONTAINER" || errorquit "couldn't close encryption for $CONTAINER"
        sleep 1
        losetup -d "$LOOPDEV" || errorquit "couldn't close loop device (${LOOPDEV})"
        ;;
    generic)
        usage
        ;;
esac