#3298 - SSL monitoring script for icinga

check_ssl_cert.sh

 #!/bin/sh
 
-# Icinga plugin that checks how many days are left until SSL certificate expires
-# Usage: <PluginDir>/check_ssl_cert -H <HOSTNAME> -P <PORT> -c <CRITICAL> -w <WARNING>
+# Icinga plugin that checks how many days are left
+# until SSL certificate expires.
+# Usage:
+# $PLUGIN_DIR/check_ssl_cert.sh -H $HOST -P $PORT -c $CRITICAL -w $WARNING
 
-PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin"
-export PATH
-PROGNAME=`basename $0`
-PROGPATH=`echo $0 | sed -e 's,[\\/][^\\/][^\\/]*$,,'`
-
-. $PROGPATH/utils.sh
+get_ssl_expiry_date() {
+  openssl s_client -connect "$1:$2" </dev/null 2>/dev/null \
+  | openssl x509 -noout -enddate 2>/dev/null
+}
 
 CURRENT_DATE=`date +%y%m%d`
-HOST=$2
-PORT=$4
-CRITICAL=$6
-WARNING=$8
+HOST="$2"
+PORT="$4"
+CRITICAL="$6"
+WARNING="$8"
+STATE_OK=0
+STATE_WARNING=1
+STATE_CRITICAL=2
+STATE_UNKNOWN=3
+OUTPUT=`get_ssl_expiry_date "$HOST" "$PORT"`
 
-DAY=`echo | openssl s_client -connect "$HOST":$PORT 2>/dev/null | openssl x509 -noout -enddate 2>/dev/null | awk '{print $2}'`
-
-if [ ! $DAY ]
+if [ -z "$OUTPUT" ]
 then
   echo "UNKNOWN - Could not connect to $HOST via port $PORT"
-  exit $STATE_UNKNOWN
+  exit "$STATE_UNKNOWN"
 fi
 
-MONTH=`echo | openssl s_client -connect "$HOST":$PORT 2>/dev/null | openssl x509 -noout -enddate | awk '{print $1}'`
-MONTH=`echo ${MONTH#*=}`
-YEAR=`echo | openssl s_client -connect "$HOST":$PORT 2>/dev/null | openssl x509 -noout -enddate | awk '{print $4}'`
+DAY=`echo "$OUTPUT" | awk '{printf "02d", $2}'`
+MONTH=`echo "$OUTPUT" | awk '{print $1}' | cut -c 10-`
+YEAR=`echo "$OUTPUT" | awk '{print $4}'`
 
-case $MONTH in
+case "$MONTH" in
+
   "Jan")
     MONTH="01"
     ;;
   "Feb")
     MONTH="02"
     ;;
   "Mar")
     MONTH="03"
     ;;
   "Apr")
@@ skipping 17 matching lines @@
   "Oct")
     MONTH="10"
     ;;
   "Nov")
     MONTH="11"
     ;;
   "Dec")
     MONTH="12"
     ;;
   "*")
+    echo "An error occured"
+    exit 1
+    ;;
 esac
 
-DIFF=$(( ($(date --date="$YEAR$MONTH$DAY" +%s) - $(date --date="$CURRENT_DATE" +%s) )/(60*60*24) ))
+EXPIRY_DATE_IN_SEC=`date -d "${YEAR}${MONTH}${DAY}" +%s`
+CURRENT_DATE_IN_SEC=`date -d "$CURRENT_DATE" +%s`
+DIFFERENCE=`expr \( "$EXPIRY_DATE_IN_SEC" - "$CURRENT_DATE_IN_SEC" \) / 86400`
 
-if [ $DIFF -le $CRITICAL ]
+if [ "$DIFFERENCE" -le "$CRITICAL" ]
 then
   echo "CRITICAL - $HOST: SSL certificate has been expired!"
-  exit $STATE_CRITICAL
-elif [ $DIFF -le $WARNING ] && [ $DIFF -gt $CRITICAL ]
+  exit "$STATE_CRITICAL"
+elif [ "$DIFFERENCE" -le "$WARNING" ]
 then
-  echo "WARNING - $HOST: SSL certificate will be expired in $DIFF days!"
-  exit $STATE_WARNING
-elif [ $DIFF -gt $WARNING ]
+  echo "WARNING - $HOST: SSL certificate will be expired in $DIFFERENCE days!"
+  exit "$STATE_WARNING"
+elif [ "$DIFFERENCE" -gt "$WARNING" ]
 then
-  echo "OK - $HOST: SSL certificate will be expired in $DIFF days"
-  exit $STATE_OK
+  echo "OK - $HOST: SSL certificate will be expired in $DIFFERENCE days"
+  exit "$STATE_OK"
 else
   echo "UNKNOWN - $HOST: Could not retrieve data"
-  exit $STATE_UNKNOWN
+  exit "$STATE_UNKNOWN"
 fi