freedombone/src/freedombone-splitkey

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#!/bin/bash
#
# .---. . .
# | | |
# |--- .--. .-. .-. .-.| .-. .--.--. |.-. .-. .--. .-.
# | | (.-' (.-' ( | ( )| | | | )( )| | (.-'
# ' ' --' --' -' - -' ' ' -' -' -' ' - --'
#
# Freedom in the Cloud
#
# A script which splits a user's gpg key into fragments which
# may then be shared
# To get a random fragment
# get a random fragment
# fragment_files=($FRAGMENTS_DIR/*)
# FRAGMENT_FILE="${files[RANDOM % ${#files[@]}]}"
# License
# =======
#
# Copyright (C) 2015-2016 Bob Mottram <bob@freedombone.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
PROJECT_NAME='freedombone'
export TEXTDOMAIN=${PROJECT_NAME}-splitkey
export TEXTDOMAINDIR="/usr/share/locale"
# Dummy password to get around not being able to create a key without passphrase
BACKUP_DUMMY_PASSWORD='backup'
KEY_FRAGMENTS=3
MY_USERNAME=
MY_EMAIL_ADDRESS=
MY_NAME=
PASSWORD_FILE=
function show_help {
echo ''
echo $"${PROJECT_NAME}-splitkey -u [username] -n [number of fragments] -e [email address] --fullname [Full name]"
echo ''
exit 0
}
while [[ $# > 1 ]]
do
key="$1"
case $key in
-h|--help)
show_help
;;
-u|--user)
shift
MY_USERNAME="$1"
;;
-n|--fragments)
shift
KEY_FRAGMENTS=$1
;;
-e|--email)
shift
MY_EMAIL_ADDRESS=$1
;;
--fullname)
shift
MY_NAME=$1
;;
--passwordfile)
shift
PASSWORD_FILE=$1
;;
*)
# unknown option
;;
esac
shift
done
if [ ! $MY_USERNAME ]; then
show_help
fi
if [ ! -d /home/$MY_USERNAME ]; then
echo $"User $MY_USERNAME does not exist on the system"
exit 7270
fi
if [ ! -d /home/$MY_USERNAME/.gnupg ]; then
echo $'No gpg key found'
exit 5393
fi
if [ $PASSWORD_FILE ]; then
if [ ! -f $PASSWORD_FILE ]; then
echo $'Password file not found'
exit 62952
fi
fi
FRAGMENTS_DIR=/home/$MY_USERNAME/.gnupg_fragments
if [ -d $FRAGMENTS_DIR ]; then
exit 0
fi
# get the gpg key ID
if [ ! $MY_EMAIL_ADDRESS ]; then
MY_EMAIL_ADDRESS=$MY_USERNAME@$HOSTNAME
fi
KEYID=$(su -c "gpg --list-keys $MY_EMAIL_ADDRESS" - $MY_USERNAME | sed -n '2p' | sed 's/^[ \t]*//')
if [ ${#KEYID} -lt 4 ]; then
echo $"gpg key for $MY_EMAIL_ADDRESS was not found"
exit 3682
fi
MY_BACKUP_KEY_ID=$(gpg --list-keys "$MY_NAME (backup key)" | sed -n '2p' | sed 's/^[ \t]*//')
if [ ${#MY_BACKUP_KEY_ID} -lt 4 ]; then
echo $"gpg backup key for '$MY_NAME' was not found"
exit 58213
fi
# create the key file
mkdir -p $FRAGMENTS_DIR
chown $MY_USERNAME:$MY_USERNAME $FRAGMENTS_DIR
KEYS_FILE=$FRAGMENTS_DIR/keyshare.asc
gpg --output $FRAGMENTS_DIR/pubkey.txt --armor --export $KEYID
if [ ! "$?" = "0" ]; then
echo $"Unable to extract public key for $KEYID"
exit 7835
fi
if [ ! $PASSWORD_FILE ]; then
gpg --output $FRAGMENTS_DIR/privkey.txt \
--armor --export-secret-key $KEYID
else
echo "$(printf `cat $PASSWORD_FILE`)" | \
gpg --batch --passphrase-fd 0 \
--output $FRAGMENTS_DIR/privkey.txt \
--armor --export-secret-key $KEYID
fi
if [ ! "$?" = "0" ]; then
echo $"Unable to extract private key for $KEYID"
exit 7823
fi
gpg --output $FRAGMENTS_DIR/backup_pubkey.txt \
--armor --export $MY_BACKUP_KEY_ID
if [ ! "$?" = "0" ]; then
shred -zu $FRAGMENTS_DIR/privkey.txt
echo $"Unable to extract backup public key for $MY_BACKUP_KEY_ID"
exit 62928
fi
echo "$BACKUP_DUMMY_PASSWORD" | \
gpg --output $FRAGMENTS_DIR/backup_privkey.txt \
--batch --passphrase-fd 0 \
--armor --export-secret-key $MY_BACKUP_KEY_ID
if [ ! "$?" = "0" ]; then
shred -zu $FRAGMENTS_DIR/privkey.txt
echo $"Unable to extract backup private key for $MY_BACKUP_KEY_ID"
exit 13783
fi
# Ensure there aren't any permissions problems when running cat
chmod +r $FRAGMENTS_DIR/privkey.txt
chmod +r $FRAGMENTS_DIR/backup_privkey.txt
cat $FRAGMENTS_DIR/pubkey.txt \
$FRAGMENTS_DIR/privkey.txt \
$FRAGMENTS_DIR/backup_pubkey.txt \
$FRAGMENTS_DIR/backup_privkey.txt > $KEYS_FILE
shred -zu $FRAGMENTS_DIR/privkey.txt
shred -zu $FRAGMENTS_DIR/pubkey.txt
shred -zu $FRAGMENTS_DIR/backup_privkey.txt
shred -zu $FRAGMENTS_DIR/backup_pubkey.txt
KEY_SHARES=$((KEY_FRAGMENTS * 2))
gfsplit -n $KEY_FRAGMENTS -m $KEY_SHARES $KEYS_FILE
if [ ! "$?" = "0" ]; then
echo $"Unable to split the gpg key"
rm -rf $FRAGMENTS_DIR
if [ -f $KEYS_FILE ]; then
shred -zu $KEYS_FILE
fi
exit 63028
fi
shred -zu $KEYS_FILE
# set permissions
chown -R $MY_USERNAME:$MY_USERNAME $FRAGMENTS_DIR
chmod -R 600 $FRAGMENTS_DIR
echo $"$KEY_SHARES key shares created"
exit 0