commit d3d14a431e23ed94102b78c80cdb37bc7ff9cfea
Author: Jonny007-MKD <me@jonny007-mkd.de>
Date:   Thu Feb 27 22:40:33 2020 +0100

    First script that parses nmaps output and checks for unexpected ports

diff --git a/check_nmap.sh b/check_nmap.sh
new file mode 100755
index 0000000..fc848ea
--- /dev/null
+++ b/check_nmap.sh
@@ -0,0 +1,146 @@
+#!/bin/bash
+
+function echoerr { echo "$@" 1>&2; }
+
+### Parse attributes ###
+
+INPUT=""
+DEBUG=false
+PORT_RANGE="1-65535"
+NMAP_ARGS=""
+KNOWN_PORTS=()
+while [[ $# -gt 0 ]]; do
+	case $1 in
+		-i|--input)
+			INPUT="$2"
+			if [ ! -f "$INPUT" ]; then
+				echoerr "The specified input file '$INPUT' does not exist"
+				exit 3
+			fi
+			shift;;
+		-h|--host)		HOST="$2"; shift;;
+		-d|--debug) 	DEBUG=true;;
+		-p|--portrange)	PORT_RANGE="$2"; shift;;
+		-k|--known)		KNOWN_PORTS+=($2); shift;;
+		--)				shift; NMAP_ARGS="$@"; shift $#;;
+		-?|--help)
+			echo "Check nmap portscan. Arguments:"
+			echo "--raid NAME: Raid name, e.g. md0"
+			echo "--input FILE: Read from this file. Default: /proc/mdstat"
+			exit 0
+			;;
+	esac
+	shift
+done
+
+if [ -z "$HOST" -a -z "$INPUT" ]; then
+	echoerr "Missing host argument (-h)"
+fi
+
+function log {
+	if $DEBUG; then
+		echo "  > $@"
+	fi
+}
+function logLine {
+	if $DEBUG; then
+		echo "  : $@"
+	fi
+}
+NL=$'\n'
+
+log "INPUT:       $INPUT"
+log "PORT_RANGE:  $PORT_RANGE"
+log "KNOWN_PORTS: ${KNOWN_PORTS[@]}"
+
+function runNmap {
+	local $portrange
+	if [ -n "$PORT_RANGE" ]; then
+		portrange="-p$PORT_RANGE"
+	else
+		portrange=""
+	fi
+
+	local $input
+	if [ -n "$INPUT" ]; then
+		while read -r line; do
+			parseLine "$line"
+		done < $INPUT
+	else
+		local $cmd
+		cmd="nmap $portrange $NMAP_ARGS -- $HOST"
+		log "$cmd"
+		while read -r line; do
+			parseLine "$line"
+		done <<< $($cmd)
+		result=$?
+		log "nmap exited with $result"
+		if [ $result -ne 0 ]; then
+			echoerr "CRITICAL - nmap exited with $result"
+			exit 2
+		fi
+	fi
+}
+
+NOW_PORTS=false
+OPEN_PORTS=()
+function parseLine {
+	local line="$1"
+	if ! $NOW_PORTS; then
+		if [[ "$line" == PORT*STATE*SERVICE ]]; then
+			NOW_PORTS=true
+		fi
+	else
+		if [ -z "$line" ]; then
+			NOW_PORTS=false
+		else
+			local x=${line/\/*}
+			OPEN_PORTS+=($x)
+		fi
+	fi
+}
+
+ERROR=false
+NEW_PORTS=()
+function comparePorts {
+	log ${KNOWN_PORTS[@]}
+	KNOWN_PORTS=($(for each in ${KNOWN_PORTS[@]}; do echo $each; done | sort))
+	log ${KNOWN_PORTS[@]}
+
+	for i in "${OPEN_PORTS[@]}"; do
+		skip=false
+		for j in "${KNOWN_PORTS[@]}"; do
+			if [ $j -eq $i ]; then
+				skip=true
+				break
+			fi
+		done
+		if ! $skip; then
+			log Unexpected open port: $i
+			NEW_PORTS+=($i)
+		fi
+	done
+	if [ ${#NEW_PORTS[@]} -gt 0 ]; then
+		ERROR=true
+	fi
+}
+
+function print {
+	if $ERROR; then
+		echo "CRITICAL - These ports should not be open: ${NEW_PORTS[@]}"
+	else
+		echo "OK"
+	fi
+
+
+	if $ERROR; then
+		exit 2
+	else
+		exit 0
+	fi
+}
+
+runNmap
+comparePorts
+print
+