-#!/bin/sh -e
+#!/usr/bin/env bash
-# MonkeySphere ssh ProxyCommand hook
-# Proxy command script to initiate a monkeysphere known_hosts update
-# before an ssh connection to host is established.
-# Can be added to ~/.ssh/config as follows:
-# ProxyCommand monkeysphere-ssh-proxycommand %h %p
+# monkeysphere-ssh-proxycommand: MonkeySphere ssh ProxyCommand hook
+#
+# The monkeysphere scripts are written by:
+# Jameson Rollins <jrollins@fifthhorseman.net>
+#
+# They are Copyright 2008, and are all released under the GPL, version 3
+# or later.
+
+# This is meant to be run as an ssh ProxyCommand to initiate a
+# monkeysphere known_hosts update before an ssh connection to host is
+# established. Can be added to ~/.ssh/config as follows:
+# ProxyCommand monkeysphere-ssh-proxycommand %h %p
+
+########################################################################
+PGRM=$(basename $0)
+
+SYSSHAREDIR=${MONKEYSPHERE_SYSSHAREDIR:-"/usr/share/monkeysphere"}
+export SYSSHAREDIR
+. "${SYSSHAREDIR}/common" || exit 1
+
+########################################################################
+# FUNCTIONS
+########################################################################
+
+usage() {
+ cat <<EOF >&2
+usage: ssh -o ProxyCommand="$(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
+
+ log "OpenPGP keys with*out* full validity found for this host:"
+ log
+
+ # retrieve the actual ssh key
+ sshKeyOffered=$(ssh-keyscan -t rsa -p "$PORT" "$HOST" 2>/dev/null | awk '{ print $2, $3 }')
+
+ userID="ssh://${HOSTP}"
+
+ # output gpg info for (exact) userid and store
+ gpgOut=$(gpg --list-key --fixed-list-mode --with-colon \
+ --with-fingerprint --with-fingerprint \
+ ="$userID" 2>/dev/null)
+
+ # loop over all lines in the gpg output and process.
+ 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
+export MONKEYSPHERE_LOG_LEVEL
+
+if [ "$1" = '--no-connect' ] ; then
+ NO_CONNECT='true'
+ shift 1
+fi
HOST="$1"
PORT="$2"
+if [ -z "$HOST" ] ; then
+ log "Host not specified."
+ usage
+ exit 255
+fi
+if [ -z "$PORT" ] ; then
+ PORT=22
+fi
+
+# set the host URI
+if [ "$PORT" != '22' ] ; then
+ HOSTP="${HOST}:${PORT}"
+else
+ HOSTP="${HOST}"
+fi
+URI="ssh://${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 ="${URI}" 2>&1 >/dev/null ; then
+ # do not check the keyserver
+ CHECK_KEYSERVER="false"
+
+# if the host is NOT in the keyring...
+else
+ # if the host key is found in the known_hosts file...
+ # FIXME: this only works for default known_hosts location
+ hostKey=$(ssh-keygen -F "$HOST" 2>/dev/null)
+
+ if [ "$hostKey" ] ; then
+ # do not check the keyserver
+ # FIXME: more nuanced checking should be done here to properly
+ # take into consideration hosts that join monkeysphere by
+ # converting an existing and known ssh key
+ CHECK_KEYSERVER="false"
+
+ # if the host key is not found in the known_hosts file...
+ else
+ # 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 "$HOST"
+monkeysphere update-known_hosts "$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 $? in
+ 0)
+ # acceptable host key found so continue to ssh
+ true
+ ;;
+ 1)
+ # no hosts at all found so also continue (drop through to
+ # regular ssh host verification)
+ true
+ ;;
+ 2)
+ # at least one *bad* host key (and no good host keys) was
+ # found, so output some usefull information
+ output_no_valid_key
+ ;;
+ *)
+ # anything else drop through
+ true
+ ;;
+esac
-# make a netcat connection to host for the ssh connection
-exec nc "$HOST" "$PORT"
+# exec a netcat passthrough to host for the ssh connection
+if [ -z "$NO_CONNECT" ] ; then
+ if (which nc 2>/dev/null >/dev/null); then
+ exec nc "$HOST" "$PORT"
+ elif (which socat 2>/dev/null >/dev/null); then
+ exec socat STDIO "TCP:$HOST:$PORT"
+ else
+ echo "Neither netcat nor socat found -- could not complete monkeysphere-ssh-proxycommand connection to $HOST:$PORT" >&2
+ exit 255
+ fi
+fi
projects / monkeysphere.git / blobdiff