#!/bin/sh

# Not needed in this version of the script
set -e

PROGPATH=$( echo $0 | sed -e 's,[\\/][^\\/][^\\/]*$,,' )
REVISION="0.1"

. $PROGPATH/utils.sh

# 
# Help function
#
usage() {
	cat <<EOF
Usage :
  $0 -h	
  $0 -H host -p port [-P protocol (tcp/udp)] [-S starttls-scheme (smtp)]
EOF
}

#
# Parameters management
#
CHECKED_PROTOCOL="tcp"	# it's almost always TCP so we don't bother to ask
OPENSSL_OPTIONS=""
while getopts hH:p:P:S: f; do
	case "$f" in
		'h')
			usage
			exit
			;;

		'H')
			CHECKED_HOSTNAME="$OPTARG"
			;;

		'p')
			CHECKED_PORT="$( printf "%d" "$OPTARG" )"
			;;

		'P')
			CHECKED_PROTOCOL="$OPTARG"
			;;

		'S')
			OPENSSL_OPTIONS="$OPENSSL_OPTIONS -starttls $OPTARG"
			;;

		\?)
			usage
			exit 1
			;;
	esac
done
if [ -z "$CHECKED_HOSTNAME" ]; then echo "ERROR empty parameter 'hostname'"; exit $STATE_UNKNOWN; fi
if [ -z "$CHECKED_PORT" ];     then echo "ERROR empty parameter 'port'";     exit $STATE_UNKNOWN; fi



# We get all TLSA record for the host
# FIXME: make a loop
# return example : "1 1 1 4A2403E87DBC4354570C5FDE24348EAED50B7791E4E2C3FC1D79B487 DDB9CC2C"
REQUEST_RECORD="_$CHECKED_PORT._$CHECKED_PROTOCOL.$CHECKED_HOSTNAME"
TLSA_RECORD="$( dig "$REQUEST_RECORD" TLSA +short | sed 's/^\([0-3]\)[[:space:]]\([01]\)[[:space:]]\([01]\)[[:space:]]/\1;\2;\3;/' | sed 's/[[:space:]]//g' )"
if [ -z "$TLSA_RECORD" ]; then echo "ERROR no TLSA record at $REQUEST_RECORD"; exit $STATE_CRITICAL; fi
if [ -z "$( echo "$TLSA_RECORD" | sed -n '/^.;/p' )" ]; then echo "ERROR record malformed or too modern for this plugin"; exit $STATE_CRITICAL; fi
CPT=0
OUTPUT_STATUS=$STATE_OK
OUTPUT_DETAILS=""
MATCH_NUMBER=0
for LINE in $TLSA_RECORD; do
	CERTIFICATE_USAGE="$( echo "$LINE" | cut -d ';' -f 1 )"
	SELECTOR="$(          echo "$LINE" | cut -d ';' -f 2 )"
	MATCHING_TYPE="$(     echo "$LINE" | cut -d ';' -f 3 )"
	DATA="$(              echo "$LINE" | cut -d ';' -f 4 )"

	# PKI verification (TODO: to implement)
	if [ "$CERTIFICATE_USAGE" -eq "0" ] || [ "$CERTIFICATE_USAGE" -eq "1" ]; then
		OUTPUT_DETAILS="$OUTPUT_DETAILS (PKI check not implemented)"
	fi

	# Pointer
	if [ "$CERTIFICATE_USAGE" -eq "1" ] || [ "$CERTIFICATE_USAGE" -eq "3" ]; then
		# Check the certificate directly
		case "$MATCHING_TYPE" in
			'0')
				# Entire info in base64
				# TODO
				;;
			'1')
				# SHA-256
				OPENSSL_RESULT="$( openssl s_client $OPENSSL_OPTIONS -connect $CHECKED_HOSTNAME:$CHECKED_PORT -servername $CHECKED_HOSTNAME </dev/null 2>/dev/null | openssl x509 -pubkey -noout | openssl rsa -pubin -outform DER 2>/dev/null | openssl dgst -sha256 | tr a-z A-Z | sed 's/.*[[:space:]]//' )"
				;;
			'2')
				# SHA-512
				OPENSSL_RESULT="$( openssl s_client $OPENSSL_OPTIONS -connect $CHECKED_HOSTNAME:$CHECKED_PORT -servername $CHECKED_HOSTNAME </dev/null 2>/dev/null | openssl x509 -pubkey -noout | openssl rsa -pubin -outform DER 2>/dev/null | openssl dgst -sha512 | tr a-z A-Z | sed 's/.*[[:space:]]//' )"
				;;
		esac
		if [ "$( echo "$DATA" | tr a-z A-Z )" = "$OPENSSL_RESULT" ]; then
			OUTPUT_DETAILS="$OUTPUT_DETAILS $( echo $LINE | sed 's/^\(.\{8\}\).*\(.\{3\}\)$/\1...\2/' )-ok"
			MATCH_NUMBER=$(( $MATCH_NUMBER + 1 ))
		else
			OUTPUT_DETAILS="$OUTPUT_DETAILS $( echo $LINE | sed 's/^\(.\{8\}\).*\(.\{3\}\)$/\1...\2/' )-NO"
		fi
	else
		# Check one of the trust anchor
		# TODO: to implement
		OUTPUT_DETAILS="$OUTPUT_DETAILS (trust anchor check not implemented)"
	fi
done
if [ "$MATCH_NUMBER" -eq 0 ]; then
	echo "ERROR no match $OUTPUT_DETAILS"
	exit $STATE_CRITICAL
else
	echo "OK $OUTPUT_DETAILS"
	exit $STATE_OK
fi