gw_menu

#!/bin/sh
#
# Copyright (c) 2016 Alex Holst, Holst Sikkerhed <href:www.holstsikkerhed.dk>
# 
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
# 
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# 
# Menu wrapper for gateway machines. Ctrl-C is ignored and user input is never
# passed to the command line. 
umask 077

HELP=/etc/gw_menu/help
HOSTS=/etc/gw_menu/hosts
USERHOSTS=/etc/gw_menu/hosts.$USER
GREETING=/etc/gw_menu/greeting
USERIP=`echo $SSH_CLIENT | awk '{ print $1 }'`

trap "" 2

if [ -f $GREETING ]; then
	grep -v "^#" $GREETING
fi

if [ ! -f $USERHOSTS ]; then
	echo Sorry, your account is not authorized to connect at this time.
	echo Please ask as indicated above to have your access reinstated.
	logger -i -t gw_menu $USERHOSTS does not exist: $USER login from $USERIP rejected.
	exit 1
fi

if [ ! -f $HOSTS ]; then
	echo Sorry, logins are not allowed at this time.
	logger -i -t gw_menu $HOSTS does not exist: $USER login from $USERIP rejected.
	exit 1
fi

	logger -i -t gw_menu $USER logged in from $USERIP

while true
do
	echo "`hostname -s`> \c"
	if read line
	then
		case "$line" in
		"")     continue;;
		esac

		set -- $line
		case "$1" in
		uptime)	uptime;;
		time) TZ=UTC date
			TZ=NZ date
			date;;
		finger|who|w) finger;;
		help)   grep -v "^#" $HELP
						while read h comments; do grep "$h" $HOSTS < $USERHOSTS; done;
						printf "\n";;
		exit|quit|bye|logout)   exit;;
		motd)   grep -v "^#" $GREETING;;
		# If the user input is not a command, it may be a hostname to
		# connect to. We do strict checking against the list of known
		# hostnames, and if there's a match we connect to the system.
				# Output from grep command, not user input, is passed to the
				# command line. 
		*)	if match=`grep "^$1$" $HOSTS` ; then
				logger -i -t gw_menu $USER connected to $match
				ssh $match
				logger -i -t gw_menu $USER disconnected from $match
								unset $match
			else
				# User input was not listed in the host file.
				echo "Unknown command or host: $line."
				echo "Enter 'help' for help."
				logger -i -t gw_menu "$USER Unknown command or host: $line"
			fi
		esac
	else
		break
	fi
done
exit