#!/bin/sh
#
#     tiger - A UN*X security checking system
#     Copyright (C) 2003 Ryan Bradetich
#
#    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 2, 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.
#
#     Please see the file `COPYING' for the complete copyright notice.
#
# check_ssh - Checks for configuration directives in the SSH configuration
#             file.
#
# 09/19/2003 - jfs - Applied patch from Ryan Braderitch fixing typoes (sp?)
# 09/03/2003 - jfs - Removed PermitRootLogin since that's checked by check_root
#             (and belongs there, IMHO) also added failsafe checks for 
#             SSHD_CONFIG which might not be configured in some systems
# 06/30/2003 - rbradetich@uswest.net - first release
#
# TODO:
#   - Add additional directives that can be checked.
#   - Figure out a clever method for integrating the default checks with the
#     normal checks.
#   - Currently suited for OpenSSH needs to be tested with other SSH daemons
#-----------------------------------------------------------------------------
#
TigerInstallDir='.'

#
# Set default base directory.
# Order or preference:
#      -B option
#      TIGERHOMEDIR environment variable
#      TigerInstallDir installed location
#
basedir=${TIGERHOMEDIR:=$TigerInstallDir}

for parm
do
   case $parm in
   -B) basedir=$2; break;;
   esac
done

#
# Verify that a config file exists there, and if it does
# source it.
#
[ ! -r $basedir/config ] && {
  echo "--ERROR-- [init002e] No 'config' file in \`$basedir'."
  exit 1
}

. $basedir/config

. $BASEDIR/initdefs

#
# If run in test mode (-t) this will verify that all required
# elements are set.
#
[ "$Tiger_TESTMODE" = 'Y' ] && {
  haveallfiles BASEDIR || exit 1
  
  echo "--CONFIG-- [init003c] $0: Configuration ok..."
  exit 0
}

#------------------------------------------------------------------------

echo
echo "# Checking sshd_config configuration files..."

haveallfiles BASEDIR || exit 1

#
# Parse the Protocol line and verify only allowed protocols are specified.
# Return 0 if the protocol is not in the approved protocol list, otherwise
# return 1.
#
parse_Protocol()
{
	line=$1

	[ -z "$Tiger_SSH_Protocol" ] && return 1
	while [ -n "$line" ]
	do
		proto=${line%%,*}
		line=${line##${proto}}
		line=${line##,}

		eval "case \"$proto\" in
			$Tiger_SSH_Protocol)
				;;
			*)
				return 0
				;;
		esac"
	done
	return 1
}

#
# Generic parsing routine for SSH Daemon directivies. 
# Return 0 if the value is not in the approved list, otherwise
# return 1.
#
parse_directive()
{
	value=$1
	list=$2

	[ -z "$list" ] && return 1
	eval "case $value in
		$list)
			return 1
			;;
		*)
			return 0
			;;
	esac"
}

#
# Parse the specified sshd_config file.
#
parse_sshd_config_file()
{
	# Declare some variables to see if specified attributes are specified
	# or if we need to check the defaults.
	found_Protocol=0
	found_RhostsAuthentication=0
	found_PasswordAuthentication=0

	while read line
	do
		line=${line%%\#*}
		[[ "$line" = Protocol* ]] && {
			found_Protocol=1
			parse_Protocol ${line##Protocol } $1 && {
				message WARN ssh001w "" "Protocol $proto is enabled in $file"
			}	
		}


		[[ "$line" = RhostsAuthentication* ]] && {
			found_RhostsAuthentication=1
			parse_directive ${line##RhostsAuthentication } $Tiger_SSH_RhostsAuthentication && {
				message WARN ssh003w "" "The RhostsAuthentication directive in $1 is set to the unapproved value: ${line##RhostsAuthentication }."
			}
		}

		[[ "$line" = PasswordAuthentication* ]] && {
			found_PasswordAuthentication=1
			parse_directive ${line##PasswordAuthentication } $Tiger_SSH_PasswordAuthentication && {
				message WARN ssh004w "" "The PasswordAuthentication directive in $1 is set to the unapproved value: ${line##PasswordAuthentication }."
			}
		}
	done < $1

	# Check the default values if the entry was not specified.
	[ $found_Protocol = 0 ] && parse_Protocol "2,1" && {
		message WARN ssh001w "" "Protocol $proto is enabled in $file"
	}
	[ $found_RhostsAuthentication = 0 ] && parse_directive "no" $Tiger_SSH_RhostsAuthentication && {
		message WARN ssh003w "" "The RhostsAuthentication directive in $1 is set to the unapproved default value: no."
	}
	[ $found_PasswordAuthentication = 0 ] && parse_directive "yes" $Tiger_SSH_PasswordAuthentication && {
		message WARN ssh004w "" "The PasswordAuthentication directive in $1 is set to the unapproved defult value: yes."
	}
}

# If SSHD_CONFIG is not defined we use some sane values
[ -z "$SSHD_CONFIG" ] && {
if [ -f /usr/local/etc/sshd_config ]; then
  SSHD_CONFIG=/usr/local/etc/sshd_config
elif [ -f /etc/sshd_config ]; then
  SSHD_CONFIG=/etc/sshd_config
elif [ -f /etc/ssh2/sshd2_config ]; then
  SSHD_CONFIG=/etc/ssh2/sshd2_config
elif [ -f /etc/ssh/sshd_config ]; then
  SSHD_CONFIG=/etc/ssh/sshd_config
fi
}

# Main loop, check all the specified sshd_config files.
if [ -z "$SSHD_CONFIG" ] 
then
	for file in $SSHD_CONFIG
	do
		[ -r "$file" ] && parse_sshd_config_file $file
	done
else
	message FAIL ssh005w "" "Cannot find a configuration file for SSH."
fi

exit 0
