/mandos/trunk

#!/bin/sh -e

# 

# Mandos key generator - create a new OpenPGP key for a Mandos client

# 

# Copyright © 2008 Teddy Hogeborn & Björn Påhlsson

# 

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU 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 General Public License for more details.

# 

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# 

# Contact the authors at <mandos@fukt.bsnet.se>.

# 

VERSION="1.0"

KEYDIR="/etc/keys/mandos"

KEYTYPE=DSA

KEYLENGTH=2048

SUBKEYTYPE=ELG-E

SUBKEYLENGTH=2048

KEYNAME="`hostname --fqdn 2>/dev/null || hostname`"

KEYEMAIL=""

KEYCOMMENT="Mandos client key"

KEYEXPIRE=0

FORCE=no

KEYCOMMENT_ORIG="$KEYCOMMENT"

mode=keygen

if [ ! -d "$KEYDIR" ]; then

    KEYDIR="/etc/mandos/keys"

fi

# Parse options

TEMP=`getopt --options vhd:t:l:n:e:c:x:f \

    --longoptions version,help,password,dir:,type:,length:,subtype:,sublength:,name:,email:,comment:,expire:,force \

    --name "$0" -- "$@"`

help(){

basename="`basename $0`"

cat <<EOF

Usage: $basename [ -v | --version ]

       $basename [ -h | --help ]

   Key creation:

       $basename [ OPTIONS ]

   Encrypted password creation:

       $basename { -p | --password } [ --name NAME ] [ --dir DIR]

Key creation options:

  -v, --version         Show program's version number and exit

  -h, --help            Show this help message and exit

  -d DIR, --dir DIR     Target directory for key files

  -t TYPE, --type TYPE  Key type.  Default is DSA.

  -l BITS, --length BITS

                        Key length in bits.  Default is 2048.

  -s TYPE, --subtype TYPE

                        Subkey type.  Default is ELG-E.

  -L BITS, --sublength BITS

                        Subkey length in bits.  Default is 2048.

  -n NAME, --name NAME  Name of key.  Default is the FQDN.

  -e ADDRESS, --email ADDRESS

                        Email address of key.  Default is empty.

  -c TEXT, --comment TEXT

                        Comment field for key.  The default value is

                        "Mandos client key".

  -x TIME, --expire TIME

                        Key expire time.  Default is no expiration.

                        See gpg(1) for syntax.

  -f, --force           Force overwriting old keys.

Password creation options:

  -p, --password        Create an encrypted password using the keys in

                        the key directory.  All options other than

                        --dir and --name are ignored.

EOF

}

eval set -- "$TEMP"

while :; do

    case "$1" in

	-p|--password) mode=password; shift;;

	-d|--dir) KEYDIR="$2"; shift 2;;

	-t|--type) KEYTYPE="$2"; shift 2;;

	-s|--subtype) SUBKEYTYPE="$2"; shift 2;;

	-l|--length) KEYLENGTH="$2"; shift 2;;

	-L|--sublength) SUBKEYLENGTH="$2"; shift 2;;

	-n|--name) KEYNAME="$2"; shift 2;;

	-e|--email) KEYEMAIL="$2"; shift 2;;

	-c|--comment) KEYCOMMENT="$2"; shift 2;;

	-x|--expire) KEYEXPIRE="$2"; shift 2;;

	-f|--force) FORCE=yes; shift;;

	-v|--version) echo "$0 $VERSION"; exit;;

	-h|--help) help; exit;;

	--) shift; break;;

	*) echo "Internal error" >&2; exit 1;;

    esac

done

if [ "$#" -gt 0 ]; then

    echo "Unknown arguments: '$@'" >&2

    exit 1

fi

SECKEYFILE="$KEYDIR/seckey.txt"

PUBKEYFILE="$KEYDIR/pubkey.txt"

# Check for some invalid values

if [ ! -d "$KEYDIR" ]; then

    echo "$KEYDIR not a directory" >&2

    exit 1

fi

if [ ! -r "$KEYDIR" ]; then

    echo "Directory $KEYDIR not readable" >&2

    exit 1

fi

if [ "$mode" = keygen ]; then

    if [ ! -w "$KEYDIR" ]; then

	echo "Directory $KEYDIR not writeable" >&2

	exit 1

    fi

    if [ -z "$KEYTYPE" ]; then

	echo "Empty key type" >&2

	exit 1

    fi

    if [ -z "$KEYNAME" ]; then

	echo "Empty key name" >&2

	exit 1

    fi

    if [ -z "$KEYLENGTH" ] || [ "$KEYLENGTH" -lt 512 ]; then

	echo "Invalid key length" >&2

	exit 1

    fi

    if [ -z "$KEYEXPIRE" ]; then

	echo "Empty key expiration" >&2

	exit 1

    fi

    # Make FORCE be 0 or 1

    case "$FORCE" in

	[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]) FORCE=1;;

	[Nn][Oo]|[Ff][Aa][Ll][Ss][Ee]|*) FORCE=0;;

    esac

    if [ \( -e "$SECKEYFILE" -o -e "$PUBKEYFILE" \) \

	-a "$FORCE" -eq 0 ]; then

	echo "Refusing to overwrite old key files; use --force" >&2

	exit 1

    fi

    # Set lines for GnuPG batch file

    if [ -n "$KEYCOMMENT" ]; then

	KEYCOMMENTLINE="Name-Comment: $KEYCOMMENT"

    fi

    if [ -n "$KEYEMAIL" ]; then

	KEYEMAILLINE="Name-Email: $KEYEMAIL"

    fi

    # Create temporary gpg batch file

    BATCHFILE="`mktemp -t mandos-keygen-batch.XXXXXXXXXX`"

fi

if [ "$mode" = password ]; then

    # Create temporary encrypted password file

    SECFILE="`mktemp -t mandos-keygen-secfile.XXXXXXXXXX`"

fi

# Create temporary key ring directory

RINGDIR="`mktemp -d -t mandos-keygen-keyrings.XXXXXXXXXX`"

# Remove temporary files on exit

trap "

set +e; \

test -n \"$SECFILE\" && shred --remove \"$SECFILE\"; \

shred --remove \"$RINGDIR\"/sec*;

test -n \"$BATCHFILE\" && rm --force \"$BATCHFILE\"; \

rm --recursive --force \"$RINGDIR\";

stty echo; \

" EXIT

umask 077

if [ "$mode" = keygen ]; then

    # Create batch file for GnuPG

    cat >"$BATCHFILE" <<-EOF

	Key-Type: $KEYTYPE

	Key-Length: $KEYLENGTH

	#Key-Usage: encrypt,sign,auth

	Subkey-Type: $SUBKEYTYPE

	Subkey-Length: $SUBKEYLENGTH

	#Subkey-Usage: encrypt,sign,auth

	Name-Real: $KEYNAME

	$KEYCOMMENTLINE

	$KEYEMAILLINE

	Expire-Date: $KEYEXPIRE

	#Preferences: <string>

	#Handle: <no-spaces>

	#%pubring pubring.gpg

	#%secring secring.gpg

	%commit

	EOF

    # Generate a new key in the key rings

    gpg --quiet --batch --no-tty --no-options --enable-dsa2 \

	--homedir "$RINGDIR" --trust-model always \

	--gen-key "$BATCHFILE"

    rm --force "$BATCHFILE"

    # Backup any old key files

    if cp --backup=numbered --force "$SECKEYFILE" "$SECKEYFILE" \

	2>/dev/null; then

	shred --remove "$SECKEYFILE"

    fi

    if cp --backup=numbered --force "$PUBKEYFILE" "$PUBKEYFILE" \

	2>/dev/null; then

	rm --force "$PUBKEYFILE"

    fi

    FILECOMMENT="Mandos client key for $KEYNAME"

    if [ "$KEYCOMMENT" != "$KEYCOMMENT_ORIG" ]; then

	FILECOMMENT="$FILECOMMENT ($KEYCOMMENT)"

    fi

    if [ -n "$KEYEMAIL" ]; then

	FILECOMMENT="$FILECOMMENT <$KEYEMAIL>"

    fi

    # Export keys from key rings to key files

    gpg --quiet --batch --no-tty --no-options --enable-dsa2 \

	--homedir "$RINGDIR" --armor --export-options export-minimal \

	--comment "$FILECOMMENT" --output "$SECKEYFILE" \

	--export-secret-keys

    gpg --quiet --batch --no-tty --no-options --enable-dsa2 \

	--homedir "$RINGDIR" --armor --export-options export-minimal \

	--comment "$FILECOMMENT" --output "$PUBKEYFILE" --export

fi

if [ "$mode" = password ]; then

    # Import keys into temporary key rings

    gpg --quiet --batch --no-tty --no-options --enable-dsa2 \

	--homedir "$RINGDIR" --trust-model always --armor \

	--import "$SECKEYFILE"

    gpg --quiet --batch --no-tty --no-options --enable-dsa2 \

	--homedir "$RINGDIR" --trust-model always --armor \

	--import "$PUBKEYFILE"

    # Get fingerprint of key

    FINGERPRINT="`gpg --quiet --batch --no-tty --no-options \

	--enable-dsa2 --homedir \"$RINGDIR\" --trust-model always \

	--fingerprint --with-colons \

	| sed --quiet \

	--expression='/^fpr:/{s/^fpr:.*:\\([0-9A-Z]*\\):\$/\\1/p;q}'`"

    test -n "$FINGERPRINT"

    FILECOMMENT="Encrypted password for a Mandos client"

    stty -echo

    echo -n "Enter passphrase: " >&2

    head --lines=1 | tr --delete '\n' \

	| gpg --quiet --batch --no-tty --no-options --enable-dsa2 \

	--homedir "$RINGDIR" --trust-model always --armor --encrypt \

	--recipient "$FINGERPRINT" --comment "$FILECOMMENT" \

	> "$SECFILE"

    echo >&2

    stty echo

    cat <<-EOF

	[$KEYNAME]

	host = $KEYNAME

	fingerprint = $FINGERPRINT

	secret =

EOF

    sed --quiet --expression='

	/^-----BEGIN PGP MESSAGE-----$/,/^-----END PGP MESSAGE-----$/{

	    /^$/,${

		# Remove 24-bit Radix-64 checksum

		s/=....$//

		# Indent four spaces

		/^[^-]/s/^/    /p

	    }

	}' < "$SECFILE"

fi

trap - EXIT

set +e

# Remove the password file, if any

if [ -n "$SECFILE" ]; then

    shred --remove "$SECFILE"

fi

# Remove the key rings

shred --remove "$RINGDIR"/sec*

rm --recursive --force "$RINGDIR"