#!/bin/sh
#
# Tomb v3, the Crypto Undertaker portable version 3
#
# A commandline tool to easily operate encryption of secret data
#
# {{{ License

# Copyright (C) 2007-2022 Dyne.org Foundation
#
# Tomb is designed, written and maintained by Denis Roio <jaromil@dyne.org>
#
# Please refer to the AUTHORS file for more information.
#
# This source code is free software; you can redistribute it and/or
# modify it under the terms of the GNU Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This source code 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.	Please refer
# to the GNU Public License for more details.
#
# You should have received a copy of the GNU Public License along with
# this source code; if not, , see <https://www.gnu.org/licenses/>.

# }}} - License

# {{{ Global variables

VERSION="3.1.0"
DATE="Nov/2022"
TOMBEXEC="$0"
TMPDIR="${TMP:-/tmp}"
TOMBTMPFILES=""
PATH="${PATH}:.:/usr/local/bin"
exitcode=0
# }}}

# {{{ Logging functions

_success() {
	echo "[*] " "$1" "$2" "$3" "$4" 1>&2
}
_message() {
	echo " .  " "$1" "$2" "$3" "$4" 1>&2
}
_warning() {
	echo "[W] " "$1" "$2" "$3" "$4" 1>&2
}
_verbose() {
	echo "[D] " "$1" "$2" "$3" "$4" 1>&2
}
_error() {
	echo "[!] " "$1" "$2" "$3" "$4" 1>&2
	exitcode=1
}
_failure() {
	echo "[!!] " "$1" "$2" "$3" "$4" 1>&2
	exitcode=1
	exit 1
}

# }}}

_success "Starting Tomb v$VERSION"

# {{{ Internal functions

_random_string() {
	len=${1:-32}
	[ "$1" != "" ] && {
		echo "print(O.random($len):base58())" | zenroom 2>/dev/null
	}
	return $?
}

_tmp_create() {
	[ -d "$TMPDIR" ] || {
		# we create the tempdir with the sticky bit on
		mkdir -m 1777 "$TMPDIR"
		[ $? = 0 ] || {
			_failure "Fatal error creating the temporary directory: %s" "$TMPDIR"
		}
	}
	tfile="${TMPDIR}/`_random_string 64`"	# Temporary file
	umask 066
	[ $? = 0 ] || {
		_failure "Fatal error setting the permission umask for temporary files"
	}
	[ -r "$tfile" ] && {
		_failure "Someone is messing up with us trying to hijack temporary files."
	}
	touch "$tfile"
	[ $? = 0 ] || {
		_failure "Fatal error creating a temporary file: %s" "$tfile"
	}
	_verbose "Created tempfile: ::1 temp file::" "$tfile"
	TOMBTMP="$tfile"
	TOMBTMPFILES="$TOMBTMPFILES:$tfile"
	return 0
}

# }}}

# {{{ FreeBSD
freebsd_mount() {
	file="$1"
	mnt="$2"
	_verbose `veracrypt -l "$file"`
	loop=`veracrypt -l "$file" | awk '{print $3}'`
	_verbose "fsck $loop"
	fsck.ext4 -p -C0 "$loop"
	lklfuse -o type=ext4 "${loop}" "$mnt"
	return $?
}

freebsd_close() {
	file="$1"
	md=`veracrypt -l "$file" | awk '{print $3}'`
	# umount "$mnt"
	_verbose "md: $md"
	mnt=`pgrep -lf "lklfuse.*$md" | awk '{print $6}'`
	_verbose "mnt: $mnt"
	lkl=`pgrep -f "lklfuse.*$md" | awk '{print $1}'`
	_verbose "kill $lkl (lklfuse on $md)"
	# trying to deail with lklfuse bug
	# https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=239831
	renice -20 $lkl
	kill $lkl
	sync
	sleep 1
	kill -9 $lkl
	# lkl should have really exited now
	_verbose "veracrypt -d $file"
	veracrypt  --text --non-interactive -d "$file"
	return $?
}
# }}}

# {{{ Linux
# usage: _mount /tmp/.veracrypt_ mountpoint
linux_mount() {
	file="$1"
	mnt="$2"
	veralist=`veracrypt -l "$file" | awk '{print($2,":",$3,":",$4)}'`
	[ "$veralist" = "" ] && {
		_error "Cannot mount tomb not yet mapped " "$file"
		return 1
	}
	loop=`echo $veralist | cut -d: -f2 | xargs`
	[ "`echo $veralist | cut -d: -f3 | xargs`" != "-" ] && {
		_error "Tomb already mounted " "$file on $loop"
		return 1
	}
	_verbose "fsck $loop"
	fsck.ext4 -p -C0 "$loop" 1>&2
	_verbose "linux_mount $mnt"
	mount "$loop" "$mnt"
	return $?
}
# }}}

# {{{ POSIX portable

# usage: echo PASSWORD | posix_create file size pim
posix_create() {
	file="$1" # must not exist
	size="$2" # size in bytes
	pim="$3" # any number
	_verbose "posix_create $file $size $pim"
	veracrypt --text --non-interactive --stdin \
		 -m nokernelcrypto \
		 -c "$file" --volume-type normal \
		 --hash sha512 --encryption serpent-aes \
		 --filesystem none --size "${size}" --pim "$pim" \
		 --random-source /dev/urandom -k ''
	return $?
}

posix_format() {
	file="$1"
	loop=`veracrypt -l "$file" | awk '{print $3}'`
	_verbose "posix_format: ${loop}"
	mkfs.ext4 -L "`basename $file`" "$loop" # -E root_owner="${user_uid}:${user_gid}" "$loop"
	return $?
}

# usage: echo PASSWORD | posix_map file pim
posix_map() {
	file="$1"
	pim="$2"
	_verbose "posix_map $file $pim"
	veracrypt --text --non-interactive --stdin \
			  --protect-hidden no -m nokernelcrypto \
			  -k '' --pim "$pim" --filesystem none \
			  "$file"
	return $?
}

posix_close() {
	file="$1"
	_verbose "posix_close $file"
	veracrypt --text --non-interactive -d "$file"
	return $?
}
# }}}

# {{{ Initialization

system="unknown"
create=""
format=""
map=""
mount=""
close=""

tomb_init() {
	system="`uname -s`"
	case "$system" in
		FreeBSD)
cat <<EOF
create=posix_create
format=posix_format
map=posix_map
mount=freebsd_mount
close=freebsd_close
EOF
			;;
		Linux)
cat <<EOF
create=posix_create
format=posix_format
map=posix_map
mount=linux_mount
close=posix_close
EOF
			;;
		*)
			_failure "Unsupported system: %s" "$system"
	esac
	echo "system=$system"
	# _verbose "system detected: %s" $system
}

# }}}


# {{{ Main
[ "$1" = "source" ] && return 0
eval "`tomb_init`"
tombfile=""
tombsize=""
PIM=69

cmd="$1"
shift 1

case "$cmd" in
	dig)
		args=2
		while [ $args -gt 0 ]; do
			[ "$1" = '-s' ] && { tombsize="$2"; shift 2; }
			[ "$1" != "" ] && { tombfile="$1"; shift 1; }
			args=$(( $args - 1 ))
		done

		[ "$tombfile" = "" ] && _failure "Missing path to tomb"
		[ "$tombsize" = "" ] && _failure "Size argument missing, use -s"
		# TODO: check if size is integer
		# [ "$tombsize" -ge 10 ] || _failure "Tombs can't be smaller than 10 mebibytes"
		[ -e "$tombfile" ] && {
			_error "A tomb exists already. I'm not digging here:"
			ls -l "$tombfile"; exit 1
		}
		_message "Commanded to dig tomb " "$tombfile" " sized $tombsize MiB"
		touch "$tombfile" || _failure "Error creating the tomb " "$tombfile"
		# dd if=/dev/urandom bs=1048576 count=$tombsize of="$tombfile" || {
		# 	_failure "Error creating the tomb " "$tombfile"
		# 	exit 1
		# }
		bytesize="$(( $tombsize * 1048576 ))"
		[ "$bytesize" = "" ] &&
			_failure "Error reading tomb size " "$tombsize"
		if [ "$system" = "Linux" ]; then
			fallocate -x -l "$bytesize" "$tombfile" ||
				_failure "Error creating the tomb " "$tombfile"
		else
			dd if=/dev/zero of="$tombfile" count="$tombsize" bs=1048576 ||
				_failure "Error creating the tomb " "$tombfile of $tombsize MiB"
		fi
		;;

	forge)
		args=1
	    [ "$1" = "" ] && _failure "Missing argument in command " "forge"
		while [ $args -gt 0 ]; do
			case "$1" in
				'-k') tombkey="$2";  shift 2 ;;
				*) tombkey="$1"; shift 1 ;;
			esac
			args=$(( $args - 1 ))
		done
		[ "$tombkey" = "" ] && _failure "Missing path to tomb key"
		[ -e "$tombkey" ] && {
			_error "A tomb key exists already. I'm not forging here:"
			ls -l "$tombkey"; exit 1
		}
		_message "Commanded to forge tomb key " "$tombkey"
		touch "$tombkey" || _failure "Error creating the tomb key " "$tombkey"
		cat <<EOF | zenroom -z | cut -d\" -f4 > "$tombkey"
		rule check version 2.0.0
		Given nothing
		When I create the random object of '64' bytes
		Then print the 'random object' as 'hex'
EOF
		 ;;

	lock)
		args=2
		while [ $args -gt 0 ]; do
			case "$1" in
				'-k') tombkey="$2";  shift 2 ;;
				*) tombfile="$1"; shift 1 ;;
			esac
			args=$(( $args - 1 ))
		done
		case "$system" in
			Linux)
				bytesize=`stat "$tombfile" | awk '/Size:/ {print $2; exit}'`
				;;
			*)
				bytesize=`stat -f '%z' "$tombfile"`
				;;
		esac
		_message "Commanded to lock tomb " "$tombfile with key $tombkey"
		[ "$tombfile" = "" ] && _failure "Missing path to tomb"
		[ -r "$tombfile" ] || _failure "Tomb file not readable"
		[ "$tombkey" = "" ] && _failure "Missing path to key"
		[ -r "$tombkey" ] || _failure "Key file not readable"
		"$create" "$tombfile" "$bytesize" "$PIM" < "$tombkey" || {
			_failure "Error creating the tomb " "$tombfile"
			exit 1
		}
		"$map" "$tombfile" "$PIM" < "$tombkey" ||
			_failure "Error mapping the tomb " "$tombfile with key $tombkey"
		"$format" "$tombfile" ||
			_error "Error formatting tomb " "$tombfile"
		"$close" "$tombfile"
		[ $exitcode = 0 ] &&
			_success "Success locking tomb " "$tombfile with key $tombkey"
		;;

	open)
		args=3
		while [ $args -gt 0 ]; do
			case "$1" in
				'-k') tombkey="$2";  shift 2 ;;
				*) if [ "$tombfile" = "" ]; then
					   tombfile="$1"
				   else
					   tombmount="$1"
				   fi
				   shift 1 ;;
			esac
			args=$(( $args - 1 ))
		done
		_message "Commanded to open tomb " "$tombfile with key $tombkey on $tombmount"
		[ "$tombfile" = "" ] && _failure "Missing path to tomb"
		[ -r "$tombfile" ] || _failure "Tomb file not readable"
		[ "$tombkey" = "" ] && _failure "Missing path to key"
		[ -r "$tombkey" ] || _failure "Key file not readable"
		[ "$tombmount" = "" ] && tombmount="`basename $tombfile`"
		"$map" "$tombfile" "$PIM" < "$tombkey"
		[ $? != 0 ] &&
			_failure "Error mapping the tomb " "$tombfile with key $tombkey"
		"$mount" "$tombfile" "$tombmount" || {
			"$close" "$tombfile"
			_failure "Error mounting the tomb " "$tombfile on $tombmount"
		}
		;;

	close)
		# args=1
		if [ "$1" = "all" ]; then
			"$close"
		elif [ -e "$1" ]; then
			"$close" "`realpath $1`" ||
				_failure "Error closing " "$1"
		elif [ "$1" = "" ]; then
			_failure "Missing argument: tomb file or mountpoint"
		else
			_failure "Wrong argument: $1"
		fi
		;;
	list)
		veracrypt -l
		;;
esac
# }}}

exit 0