Tomb/src/tomb

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#!/bin/bash
#
# Tomb
#
# a simple commandline tool to create and operate encrypted storage
#
# Copyleft (C) 2007-2010 Denis Roio <jaromil@dyne.org>
#
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# Tomb development is supported by: NOONE.
# Would you like to support it and engrave your name on this software?
# Contact me!
#
# thanks to Gabriele "Asbesto Molesto" Zaverio
# for suggesting the perfect name for this tool.
#
# 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, write to:
# Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
VERSION=0.8
DATE=Aug/2010
PATH=/usr/bin:/usr/sbin:/bin:/sbin
# standard output message routines
# it's always useful to wrap them, in case we change behaviour later
notice() { echo "[*] $1"; }
act() { echo " . $1"; }
error() { echo "[!] $1"; }
func() { if [ $DEBUG ]; then echo "[D] $1"; fi }
# which dd command to use
which dcfldd > /dev/null
if [ $? = 0 ]; then
DD="dcfldd"
else
DD=dd
fi
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# which wipe command to use
which wipe > /dev/null
if [ $? = 0 ]; then
WIPE="wipe -f -s -q"
else
WIPE="rm -f"
fi
# usb auto detect
# tested on ubuntu 10.04 - please test and patch on other systems if you can
ask_usbkey() {
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notice "looking for key $1 on usb"
echo -n " . please insert your usb key "
plugged=false
while [ "$plugged" != "true" ]; do
dmesg | tail -n 12 | grep -q 'new.*USB device'
if [ $? = 0 ]; then plugged=true; fi
echo -n "."
sleep .5
done
echo
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echo -n " . usb key inserted, opening "
attached=false
while [ "$attached" != "true" ]; do
dmesg | tail -n 3| grep -q 'Attached.*removable disk'
if [ $? = 0 ]; then attached=true; fi
echo -n "."
sleep .5
done
# get the first partition
usbpart=`dmesg |tail -n 8 | grep ' sd.:' |cut -d: -f2 |tr -d ' '`
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# what that it is mounted
mounted=false
while [ "$mounted" != "true" ]; do
cat /proc/mounts | tail -n 2 | grep -q $usbpart
if [ $? = 0 ]; then mounted=true; fi
echo -n "."
sleep .5
done
# check where it is mounted
usbmount=`cat /proc/mounts | awk -v p=$usbpart '{ if( $1 == "/dev/" p) print $2 }'`
echo
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act "usb key mounted on $usbmount"
export usbkey_mount=$usbmount
return 0
}
# user interface (just to ask the password)
ask_password() {
xhost 2>/dev/null
if [ $? = 0 ]; then # we have access to the X display
if [ -x /usr/bin/ssh-askpass ]; then # debian has this
export scolopendro="`ssh-askpass "Tomb: provide the password to unlock"`"
return
fi
else # we'll collect the password from commandline
act "Tomb: provide the password to unlock"
echo -n " > "
read -s scolopendro
export scolopendro
fi
# just in case we'd like to have dialog supported too:
# dialog --backtitle "This file is encrypted for privacy protection" \
# --title "Security check" --insecure \
# --passwordbox "Enter password:" 10 30 2> /var/run/.scolopendro
}
############################
### main()
###
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notice "Tomb - simple commandline tool for encrypted storage"
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act "version $VERSION ($DATE) by Jaromil @ dyne.org"
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act ""
func "invoked with args \"$*\" "
func "running on `date`"
OPTS=`getopt -o hvs:k: -n 'tomb' -- "$@"`
while true; do
case "$1" in
-h)
notice "Syntax: tomb [options] command [file] [mountpoint | size]"
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act ""
notice "Options:"
act "-h print this help"
act "-v print out the version information for this tool"
act "-s size of the storage file when creating one (in MBytes)"
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act "-k path to the key to use for decryption"
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act ""
notice "Commands:"
act "create create a new encrypted storage FILE and keys"
act "mount mount an existing storage FILE on MOUNTPOINT"
act "umount unmounts a mounted storage MOUNTPOINT"
echo; exit 2 ;;
-v)
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# print out the GPL license in this file
cat $0 | awk '
BEGIN { license=0 }
/^# This source/ { license=1 }
{ if(license==1) print " " $0 }
/MA 02139, USA.$/ { license=0 }
'
act ""
exit 0 ;;
-s) SIZE=$2; shift 2 ;;
-k) KEY=$2; shift 2 ;;
--) shift; break ;;
*) CMD=$1; FILE=$2; MOUNT=$3; break ;;
esac
done
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if [ -z $CMD ]; then
error "first argument missing, use -h for help"
exit 0
fi
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id | grep root > /dev/null
if [ $? != 0 ]; then
error "This program must be run as root to produce results"
exit 1
fi
func "command: $CMD for file $FILE"
tombdir=${HOME}/.tomb
tombtab=${tombdir}/fstab
if ! [ -r ${tombtab} ]; then
act "creating tomb filesystem tab in your home"
mkdir -p ${HOME}/.tomb
echo "# entombed filesystem information, see man tomb" > ${tombtab}
echo "# format here is similar to the system wide fstab" >> ${tombtab}
echo "# <file system> <mount point> <type> <options> <key>" >> ${tombtab}
fi
create_tomb() {
notice "Creating a new tomb in ${FILE}"
if [ -z $SIZE ]; then
if [ $MOUNT ]; then
SIZE=$MOUNT
else
error "size is not specified, please use -s option when creating a tomb"
exit 0
fi
fi
SIZE_4k=`expr \( $SIZE \* 1000 \) / 4`
act "Generating file of ${SIZE}Mb (${SIZE_4k} blocks of 4Kb)"
# TODO: use dd_rescue and/or dcfldd
$DD if=/dev/urandom bs=4k count=${SIZE_4k} of=${FILE}
# dd if=/dev/urandom bs=4k count=${SIZE_4k} of=${FILE}
if [ $? = 0 -a -e ${FILE} ]; then
act "OK: `ls -lh ${FILE}`"
else
error "Error creating the nest file ${FILE} : (dd if=/dev/zero of=${FILE} bs=4k count=$SIZE_4k)"
sleep 4
exit 0
fi
mkdir -p /tmp/tomb
modprobe dm-crypt
modprobe aes-i586
nstloop=`losetup -f` # get the number for next loopback device
losetup -f ${FILE} # allocates the next loopback for our file
keytmp=`tempfile`
act "Generating secret key..."
act "this operation takes time, computer use helps to gather more entropy."
cat /dev/random | dd bs=1 count=256 of=${keytmp}
notice "Setup your secret key file ${FILE}.gpg"
# here user is prompted for key password
gpg -o "${FILE}.gpg" --no-options --openpgp -c -a ${keytmp}
while [ $? = 2 ]; do
gpg -o "${FILE}.gpg" --no-options --openpgp -c -a ${keytmp}
done
act "formatting Luks mapped device"
# dm-crypt only supports sha1
# but we can use aes-cbc-essiv with sha256 for better security
# see http://clemens.endorphin.org/LinuxHDEncSettings
cryptsetup --batch-mode \
--cipher aes-cbc-essiv:sha256 --key-size 256 \
luksFormat ${nstloop} ${keytmp}
if ! [ $? = 0 ]; then
act "operation aborted."
exit 0
fi
cryptsetup --key-file ${keytmp} --cipher aes luksOpen ${nstloop} tomb.tmp
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$WIPE ${keytmp}
notice "Your tomb is read on ${FILE} and secured with key ${FILE}.gpg"
act "now plug an external usb device to save the key separately:"
ask_usbkey
if ! [ -w ${usbkey_mount} ]; then
error "cannot save the key in a separate place, move it yourself later."
else
mkdir -p ${usbkey_mount}/.tomb
cp -v ${FILE}.gpg ${usbkey_mount}/.tomb/
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chmod -R go-rwx ${usbkey_mount}/.tomb
rm -rf ${FILE}.gpg
fi
# cryptsetup luksDump ${nstloop}
act "formatting your Tomb with Ext4 filesystem"
mkfs.ext4 -q -F -j -L "`hostname`-`date +%s`" /dev/mapper/tomb.tmp
if [ $? = 0 ]; then
act "OK, encrypted storage succesfully formatted"
else
act "error formatting Tomb"
fi
sync
cryptsetup luksClose tomb.tmp
losetup -d ${nstloop}
notice "done creating $FILE encrypted storage (using Luks dm-crypt AES/SHA256)"
}
mount_tomb() {
if [ -z $KEY ]; then
enc_key="`basename ${FILE}.gpg`"
else
enc_key="$KEY"
fi
notice "mounting $FILE on mountpoint $MOUNT"
if [ -z $MOUNT ]; then
error "you need to specify a MOUNTPOINT for the mount command"
exit 0
fi
if ! [ -x $MOUNT ]; then
error "mountpoint $MOUNT doesn't exist"
exit 0
fi
# check if key file is present
if ! [ -r "${enc_key}" ]; then
error "encryption key ${enc_key} not found on disk"
error "use -k option to specify which key to use"
error "or provide a usb key, or press ctrl-c to abort"
ask_usbkey
# returns usbkey_mount, now check if the key is there
if [ -r ${usbkey_mount}/.tomb/${enc_key} ]; then
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enc_key=${usbkey_mount}/.tomb/${enc_key}
notice "key found on ${enc_key}"
else
error "key is missing."
exit 1
fi
fi
nstloop=`losetup -f`
losetup -f ${FILE}
act "check for a valid LUKS encrypted device"
cryptsetup isLuks ${nstloop}
if [ $? != 0 ]; then
# is it a LUKS encrypted nest? see cryptsetup(1)
error "$FILE is not a valid Luks encrypted storage file"
exit 0
fi
modprobe dm-crypt
modprobe aes-i586
# save date of mount in minutes since 1970
mapdate="`date +%s`"
mapdate="`echo ${mapdate}/60 | bc -l | cut -d. -f1`"
mapper="tomb.`basename $FILE | cut -d. -f1`.$mapdate.`basename $nstloop`"
notice "Password is required for key ${enc_key}"
for c in 1 2 3; do
ask_password
echo "${scolopendro}" \
| gpg --passphrase-fd 0 --no-tty --no-options \
-d "${enc_key}" 2>/dev/null \
| cryptsetup --key-file - luksOpen ${nstloop} ${mapper}
unset scolopendro
if [ -r /dev/mapper/${mapper} ]; then
break; # password was correct
fi
done
if ! [ -r /dev/mapper/${mapper} ]; then
error "failure mounting the encrypted file"
tail /var/log/messages
losetup -d ${nstloop}
return
fi
act "encrypted storage filesystem check"
fsck.ext4 -p -C0 /dev/mapper/${mapper}
mount -t ext4 -o rw,noatime,nodev /dev/mapper/${mapper} ${MOUNT}
notice "encrypted storage $FILE succesfully mounted on $MOUNT"
}
umount_tomb() {
if [ -z $FILE ]; then
how_many_tombs="`ls /dev/mapper/tomb* 2>/dev/null | wc -w`"
if [ $how_many_tombs = 0 ]; then
error "there is no tomb found to be mounted"
return
elif [ $how_many_tombs = 1 ]; then
mapper=`ls /dev/mapper/tomb* 2>/dev/null`
FILE=`mount | grep $mapper | awk '{print $3}'`
else
error "too many tombs mounted, please specify which to unmount:"
ls /dev/mapper/tomb*
echo
return
fi
else
if ! [ -r $FILE ]; then
error "tomb not found: $FILE"
error "please specify the full /dev/mapper/tomb* path"
return
fi
mapper=$FILE
FILE=`mount | grep $mapper | awk '{print $3}'`
fi
if [ "$mapper" = "" ]; then
error "$FILE is not mounted"
return
fi
mapper=`basename $mapper`
if ! [ -r /dev/mapper/${mapper} ]; then
error "tomb doesn't seems to be mounted:"
error "${mapper} is not present in /dev/mapper"
exit 1
fi
umount ${FILE}
if ! [ $? = 0 ]; then
error "error occurred in umount ${FILE}"
exit 0
fi
cryptsetup luksClose ${mapper}
if ! [ $? = 0 ]; then
error "error occurred in cryptsetup luksClose ${mapper}"
exit 0
fi
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losetup -d "/dev/`echo $mapper | cut -d. -f4`"
# echo ${nstloop} | grep loop 1>/dev/null 2>/dev/null
# # if it's a loopback then we need to do losetup -d
# if [ $? = 0 ]; then
# losetup -d ${nstloop}
# if ! [ $? = 0 ]; then
# error "error occurred in losetup -d ${nstloop}"
# exit 0
# fi
# fi
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notice "crypt storage ${mapper} unmounted"
}
case "$CMD" in
create) create_tomb ;;
format) format_tomb ;;
mount) mount_tomb ;;
umount) umount_tomb ;;
unmount) umount_tomb ;;
*) error "command \"$CMD\" not recognized"
act "try -h for help"
;;
esac