-#!/bin/sh
+#!/usr/bin/env bash
# monkeysphere-ssh-proxycommand: MonkeySphere ssh ProxyCommand hook
#
# ProxyCommand monkeysphere-ssh-proxycommand %h %p
########################################################################
-SHARE=${MONKEYSPHERE_SHARE:-"/usr/share/monkeysphere"}
-. "${SHARE}/common" || exit 1
+PGRM=$(basename $0)
+SYSSHAREDIR=${MONKEYSPHERE_SYSSHAREDIR:-"/usr/share/monkeysphere"}
+export SYSSHAREDIR
+. "${SYSSHAREDIR}/common" || exit 1
+
+########################################################################
+# FUNCTIONS
########################################################################
usage() {
-cat <<EOF >&2
+ cat <<EOF >&2
usage: ssh -o ProxyCommand="$(basename $0) %h %p" ...
EOF
}
+log() {
+ echo "$@" >&2
+}
+
+output_no_valid_key() {
+ local sshKeyOffered
+ local userID
+ local type
+ local validity
+ local keyid
+ local uidfpr
+ local usage
+ local sshKeyGPG
+ local sshFingerprint
+
+ userID="ssh://${HOSTP}"
+
+ log "Monkeysphere found only OpenPGP keys for this host with*out* full validity."
+ log "host: $userID"
+ log
+
+ # retrieve the actual ssh key
+ sshKeyOffered=$(ssh-keyscan -t rsa -p "$PORT" "$HOST" 2>/dev/null | awk '{ print $2, $3 }')
+ # FIXME: should we do any checks for failed keyscans, eg host not
+ # found?
+
+ # output gpg info for userid and store
+ gpgOut=$(gpg --list-key --fixed-list-mode --with-colon \
+ --with-fingerprint --with-fingerprint \
+ ="$userID" 2>/dev/null)
+
+ # find all 'pub' and 'sub' lines in the gpg output, which each
+ # represent a retrieved key for the user ID
+ echo "$gpgOut" | cut -d: -f1,2,5,10,12 | \
+ while IFS=: read -r type validity keyid uidfpr usage ; do
+ case $type in
+ 'pub'|'sub')
+ # get the ssh key of the gpg key
+ sshKeyGPG=$(gpg2ssh "$keyid")
+
+ # if one of keys found matches the one offered by the
+ # host, then output info
+ if [ "$sshKeyGPG" = "$sshKeyOffered" ] ; then
+
+ # get the fingerprint of the ssh key
+ tmpkey=$(mktemp ${TMPDIR:-/tmp}/tmp.XXXXXXXXXX)
+ echo "$sshKeyGPG" > "$tmpkey"
+ sshFingerprint=$(ssh-keygen -l -f "$tmpkey" | awk '{ print $2 }')
+ rm -rf "$tmpkey"
+
+ # output gpg info
+ gpg --check-sigs \
+ --list-options show-uid-validity \
+ "$keyid" >&2
+
+ # output ssh fingerprint
+ log "RSA key fingerprint is ${sshFingerprint}."
+ log "Falling through to standard ssh host checking."
+ log
+ fi
+ ;;
+ esac
+ done
+}
+
########################################################################
# export the monkeysphere log level
HOST="$1"
PORT="$2"
-MS_HOME=${MS_HOME:-"${HOME}/.config/monkeysphere"}
-
if [ -z "$HOST" ] ; then
- echo "Host not specified." >&2
+ log "Host not specified."
usage
exit 255
fi
fi
URI="ssh://${HOSTP}"
+# specify keyserver checking. the behavior of this proxy command is
+# intentionally different than that of running monkeyesphere normally,
+# and keyserver checking is intentionally done under certain
+# circumstances. This can be overridden by setting the
+# MONKEYSPHERE_CHECK_KEYSERVER environment variable.
+
# if the host is in the gpg keyring...
if gpg --list-key ="${URI}" 2>&1 >/dev/null ; then
# do not check the keyserver
CHECK_KEYSERVER="true"
fi
fi
-
+# set and export the variable for use by monkeysphere
MONKEYSPHERE_CHECK_KEYSERVER=${MONKEYSPHERE_CHECK_KEYSERVER:="$CHECK_KEYSERVER"}
export MONKEYSPHERE_CHECK_KEYSERVER
# update the known_hosts file for the host
monkeysphere update-known_hosts "$HOSTP"
+# output on depending on the return of the update-known_hosts
+# subcommand, which is (ultimately) the return code of the
+# update_known_hosts function in common
+case $? in
+ 0)
+ # acceptable host key found so continue to ssh
+ true
+ ;;
+ 1)
+ # no hosts at all found so also continue (drop through to
+ # regular ssh host verification)
+ true
+ ;;
+ 2)
+ # at least one *bad* host key (and no good host keys) was
+ # found, so output some usefull information
+ output_no_valid_key
+ ;;
+ *)
+ # anything else drop through
+ true
+ ;;
+esac
+
# exec a netcat passthrough to host for the ssh connection
if [ -z "$NO_CONNECT" ] ; then
if (which nc 2>/dev/null >/dev/null); then