src/monkeysphere-host



#!/usr/bin/env bash

# monkeysphere-host: Monkeysphere host admin tool
#
# The monkeysphere scripts are written by:
# Jameson Rollins <jrollins@finestructure.net>
# Jamie McClelland <jm@mayfirst.org>
# Daniel Kahn Gillmor <dkg@fifthhorseman.net>
# Micah Anderson <micah@riseup.net>
#
# They are Copyright 2008-2009, and are all released under the GPL,
# version 3 or later.

########################################################################
set -e

# set the pipefail option so pipelines fail on first command failure
set -o pipefail

PGRM=$(basename $0)

SYSSHAREDIR=${MONKEYSPHERE_SYSSHAREDIR:-"/usr/share/monkeysphere"}
export SYSSHAREDIR
. "${SYSSHAREDIR}/common" || exit 1

SYSDATADIR=${MONKEYSPHERE_SYSDATADIR:-"/var/lib/monkeysphere"}
export SYSDATADIR

# sharedir for host functions
MHSHAREDIR="${SYSSHAREDIR}/mh"

# datadir for host functions
MHDATADIR="${SYSDATADIR}/host"

# host pub key files
HOST_KEY_PUB="${SYSDATADIR}/ssh_host_rsa_key.pub"
HOST_KEY_PUB_GPG="${SYSDATADIR}/ssh_host_rsa_key.pub.gpg"

# UTC date in ISO 8601 format if needed
DATE=$(date -u '+%FT%T')

# unset some environment variables that could screw things up
unset GREP_OPTIONS

# default return code
RETURN=0

########################################################################
# FUNCTIONS
########################################################################

usage() {
    cat <<EOF >&2
usage: $PGRM <subcommand> [options] [args]
Monkeysphere host admin tool.

subcommands:
 show-key (s)                        output all host key information
 set-expire (e) EXPIRE               set host key expiration
 add-hostname (n+) NAME[:PORT]       add hostname user ID to host key
 revoke-hostname (n-) NAME[:PORT]    revoke hostname user ID
 add-revoker (o) FINGERPRINT         add a revoker to the host key
 revoke-key (r)                      revoke host key
 publish-key (p)                     publish host key to keyserver

 expert <expert-subcommand>          run expert command
 expert help                         expert command help

 version (v)                         show version number
 help (h,?)                          this help

EOF
}

# function to interact with the gpg keyring
gpg_host() {
    GNUPGHOME="$GNUPGHOME_HOST" gpg "$@"
}

# command to list the info about the host key, in colon format
gpg_host_list() {
    gpg_host --list-keys --with-colons --fixed-list-mode \
    --with-fingerprint --with-fingerprint \
    "0x${HOST_FINGERPRINT}!"

}

# command for edit key scripts, takes scripts on stdin
gpg_host_edit() {
    gpg_host --quiet --command-fd 0 --edit-key \
    "0x${HOST_FINGERPRINT}!" "$@"
}

# export the host key to stdout
gpg_host_export() {
    gpg_host --export --armor --export-options export-minimal \
    "0x${HOST_FINGERPRINT}!"
}

# export the host secret key to the monkeysphere ssh sec key file
# NOTE: assumes that the primary key is the proper key to use
create_ssh_sec_file() {
    log debug "creating ssh secret key file..."
    (umask 077 && \
    gpg_host --export-secret-key "$HOST_FINGERPRINT" | \
    openpgp2ssh "$HOST_FINGERPRINT" > "${MHDATADIR}/ssh_host_rsa_key")
    log info "SSH host secret key file: ${MHDATADIR}/ssh_host_rsa_key"
}

# export the host public key to the monkeysphere ssh pub key file
create_ssh_pub_file() {
    log debug "creating ssh public key file..."
    ssh-keygen -y -f "${MHDATADIR}/ssh_host_rsa_key" > "$HOST_KEY_PUB"
    log info "SSH host public key file: $HOST_KEY_PUB"
}

# export the host public key to the monkeysphere gpg pub key file
create_gpg_pub_file() {
    log debug "creating openpgp public key file..."
    gpg_host_export > "$HOST_KEY_PUB_GPG"
    log info "GPG host public key file: $HOST_KEY_PUB_GPG"
}

# load the host fingerprint into the fingerprint variable, using the
# export gpg pub key file
load_fingerprint() {
    if [ -f "$HOST_KEY_PUB_GPG" ] ; then
    HOST_FINGERPRINT=$( \
        (FUBAR=$(mktemp -d) && export GNUPGHOME="$FUBAR" \
        && gpg --quiet --import \
        && gpg --quiet --list-keys --with-colons --with-fingerprint \
        && rm -rf "$FUBAR") <"$HOST_KEY_PUB_GPG" \
        | grep '^fpr:' | cut -d: -f10 )
    else
    HOST_FINGERPRINT=
    fi
}

# load the host fingerprint into the fingerprint variable, using the
# gpg host secret key
load_fingerprint_secret() {
    HOST_FINGERPRINT=$( \
    gpg_host --quiet --list-secret-key \
    --with-colons --with-fingerprint \
    | grep '^fpr:' | cut -d: -f10 )
}

# output host key ssh fingerprint
load_ssh_fingerprint() {
    [ -f "$HOST_KEY_PUB" ] || return 0
    HOST_FINGERPRINT_SSH=$(ssh-keygen -l -f "$HOST_KEY_PUB" \
    | awk '{ print $1, $2, $4 }')
}

# fail if host key present
check_host_key() {
    [ -z "$HOST_FINGERPRINT" ] \
    || failure "An OpenPGP host key already exists."
}

# fail if host key not present
check_host_no_key() {
    [ "$HOST_FINGERPRINT" ] \
    || failure "You don't appear to have a Monkeysphere host key on this server.  Please run 'monkeysphere-host expert import-key' first."
}

# output the index of a user ID on the host key
# return 1 if user ID not found
find_host_userid() {
    local userID="$1"
    local tmpuidMatch
    local line

    # match to only ultimately trusted user IDs
    tmpuidMatch="u:$(echo $userID | gpg_escape)"

    # find the index of the requsted user ID
    # NOTE: this is based on circumstantial evidence that the order of
    # this output is the appropriate index
    line=$(gpg_host_list | egrep '^(uid|uat):' | cut -f2,10 -d: | \
    grep -n -x -F "$tmpuidMatch" 2>/dev/null)

    if [ "$line" ] ; then
    echo ${line%%:*}
    return 0
    else
    return 1
    fi
}

# show info about the host key
show_key() {
    gpg_host --fingerprint --list-key --list-options show-unusable-uids \
    "0x${HOST_FINGERPRINT}!" 2>/dev/null
    # FIXME: make sure expiration date is shown

    echo "OpenPGP fingerprint: $HOST_FINGERPRINT"

    load_ssh_fingerprint

    if [ "$HOST_FINGERPRINT_SSH" ] ; then
    echo "ssh fingerprint: $HOST_FINGERPRINT_SSH"
    else
    log error "SSH host key not found."
    fi

    # FIXME: other relevant key parameters?
}

########################################################################
# MAIN
########################################################################

# unset variables that should be defined only in config file
unset KEYSERVER
unset MONKEYSPHERE_USER

# load configuration file
[ -e ${MONKEYSPHERE_HOST_CONFIG:="${SYSCONFIGDIR}/monkeysphere-host.conf"} ] && . "$MONKEYSPHERE_HOST_CONFIG"

# set empty config variable with ones from the environment, or with
# defaults
LOG_LEVEL=${MONKEYSPHERE_LOG_LEVEL:=${LOG_LEVEL:="INFO"}}
KEYSERVER=${MONKEYSPHERE_KEYSERVER:=${KEYSERVER:="pool.sks-keyservers.net"}}
AUTHORIZED_USER_IDS=${MONKEYSPHERE_AUTHORIZED_USER_IDS:=${AUTHORIZED_USER_IDS:="%h/.monkeysphere/authorized_user_ids"}}
RAW_AUTHORIZED_KEYS=${MONKEYSPHERE_RAW_AUTHORIZED_KEYS:=${RAW_AUTHORIZED_KEYS:="%h/.ssh/authorized_keys"}}
MONKEYSPHERE_USER=${MONKEYSPHERE_MONKEYSPHERE_USER:=${MONKEYSPHERE_USER:="monkeysphere"}}

# other variables
CHECK_KEYSERVER=${MONKEYSPHERE_CHECK_KEYSERVER:="true"}
GNUPGHOME_HOST=${MONKEYSPHERE_GNUPGHOME_HOST:="${MHDATADIR}"}

# export variables needed in su invocation
export DATE
export MODE
export LOG_LEVEL
export MONKEYSPHERE_USER
export KEYSERVER
export GNUPGHOME_HOST
export GNUPGHOME
export HOST_FINGERPRINT=
export HOST_FINGERPRINT_SSH=

# get subcommand
COMMAND="$1"
[ "$COMMAND" ] || failure "Type '$PGRM help' for usage."
shift

case $COMMAND in
    'show-key'|'show'|'s')
    load_fingerprint
    check_host_no_key
    show_key
    ;;

    'set-expire'|'extend-key'|'e')
    load_fingerprint
    check_host_no_key
    source "${MHSHAREDIR}/set_expire"
    set_expire "$@"
    ;;

    'add-hostname'|'add-name'|'n+')
    load_fingerprint
    check_host_no_key
    source "${MHSHAREDIR}/add_hostname"
    add_hostname "$@"
    ;;

    'revoke-hostname'|'revoke-name'|'n-')
    load_fingerprint
    check_host_no_key
    source "${MHSHAREDIR}/revoke_hostname"
    revoke_hostname "$@"
    ;;

    'add-revoker'|'o')
    load_fingerprint
    check_host_no_key
    source "${MHSHAREDIR}/add_revoker"
    add_revoker "$@"
    ;;

    'revoke-key'|'r')
    load_fingerprint
    check_host_no_key
    source "${MHSHAREDIR}/revoke_key"
    revoke_key "$@"
    ;;

    'publish-key'|'publish'|'p')
    load_fingerprint
    check_host_no_key
    source "${MHSHAREDIR}/publish_key"
    publish_key
    ;;

    'expert')
    SUBCOMMAND="$1"
    shift
    case "$SUBCOMMAND" in
        'help'|'h'|'?')
        cat <<EOF
usage: $PGRM expert <subcommand> [options] [args]

expert subcommands:
 import-key (i) [NAME[:PORT]]        import existing ssh key to gpg
 gen-key (g) [NAME[:PORT]]           generate gpg key for the host
   --length (-l) BITS                  key length in bits (2048)
 diagnostics (d)                     monkeysphere host status

EOF
        ;;

        'import-key'|'i')
        load_fingerprint
        check_host_key
        source "${MHSHAREDIR}/import_key"
        import_key "$@"
        ;;

        'gen-key'|'g')
        load_fingerprint
        check_host_key
        source "${MHSHAREDIR}/gen_key"
        gen_key "$@"
        ;;

        'diagnostics'|'d')
        source "${MHSHAREDIR}/diagnostics"
        diagnostics
        ;;

        *)
        failure "Unknown expert subcommand: '$COMMAND'
Type '$PGRM help' for usage."
        ;;
    esac
    ;;

    'version'|'v')
    echo "$VERSION"
    ;;

    '--help'|'help'|'-h'|'h'|'?')
        usage
        ;;

    *)
        failure "Unknown command: '$COMMAND'
Type '$PGRM help' for usage."
        ;;
esac

exit "$RETURN"