[denyhosts] Cleanup syntax

Signed-off-by: Olivier Mehani <shtrom@ssji.net>

1 files changed, 50 insertions, 50 deletions

diff --git a/openbsd/denyhost.sh b/openbsd/denyhost.sh
index da59588..4a149dc 100755
--- a/openbsd/denyhost.sh
+++ b/openbsd/denyhost.sh
@@ -17,7 +17,7 @@
 # also be a good idea)
 #
 
-LOCAL_ADDR=root@`hostname`
+LOCAL_ADDR=root@$(hostname)
 HTTP_LOG=/srv/www/logs/access_log
 HTTP_PATTERN="etc.passwd"
 SSH_LOG=/var/log/authlog
@@ -27,57 +27,57 @@ EXPIRY=604800 # s; 1w
 BLOCKERS_FILE=/etc/blockers.list
 TMP_DIR=/tmp
 
-PATH=/usr/local/bin:$PATH
+PATH=/usr/local/bin:${PATH}
 
 PIDFILE=/var/run/denyhost.sh.pid
 
 MAIL=mail
 
 # Exit if another instance is already running.
-if test -e $PIDFILE && kill -0 `cat $PIDFILE` 2>/dev/null; then
-  echo "$0 process already running (`cat $PIDFILE`), exiting" >&2
+if test -e ${PIDFILE} && kill -0 $(cat ${PIDFILE}) 2>/dev/null; then
+  echo "$0 process already running ($(cat ${PIDFILE})), exiting" >&2
   exit 0
 else
-  echo $$ > $PIDFILE
+  echo $$ > ${PIDFILE}
 fi
 
 function process_ip
 {
-	HOST_FILE=`mktemp ${TMP_DIR}/denyhost.host.XXXXXX`
-	host $IP > $HOST_FILE
-	HOSTS=`gsed -n "s/.*\(:\|domain name pointer\) \(.\+\)/\2/p" $HOST_FILE | \
-		gsed ':a N;s/\n/, /g; ta'`
-
-	WHOIS_FILE=`mktemp ${TMP_DIR}/denyhost.whois.XXXXXX`
-	whois $IP > $WHOIS_FILE
-	ABUSE=`extract_email $WHOIS_FILE`
-
-	HTTP_HOST_LOG=`mktemp ${TMP_DIR}/denyhost.host_http.log.XXXXXX`
-	grep $IP $HTTP_FILTERED_LOG > $HTTP_HOST_LOG
-
-	SSH_HOST_LOG=`mktemp ${TMP_DIR}/denyhost.host_ssh.log.XXXXXX`
-	grep $IP $SSH_FILTERED_LOG > $SSH_HOST_LOG
-	LOGINS=`gsed -n "s/.*sshd\[[0-9]\+\]: \(Invalid user\|Failed password for\( invalid user\)\?\) \([^[:space:]]\+\) from.*/\3/p" $SSH_HOST_LOG | \
-		sort | uniq | gsed ':a N;s/\n/, /g; ta'`
-
-	if [ -z "$ABUSE" ]; then
-		NETS=`gsed -n "s/.*\(NET-[-0-9]\+\).*/\1/p" $WHOIS_FILE`
-		for NET in $NETS; do
-			whois $NET >> $WHOIS_FILE
+	HOST_FILE=$(mktemp ${TMP_DIR}/denyhost.host.XXXXXX)
+	host ${IP} > ${HOST_FILE}
+	HOSTS=$(gsed -n "s/.*\(:\|domain name pointer\) \(.\+\)/\2/p" ${HOST_FILE} | \
+		gsed ':a N;s/\n/, /g; ta')
+
+	WHOIS_FILE=$(mktemp ${TMP_DIR}/denyhost.whois.XXXXXX)
+	whois ${IP} > ${WHOIS_FILE}
+	ABUSE=$(extract_email ${WHOIS_FILE})
+
+	HTTP_HOST_LOG=$(mktemp ${TMP_DIR}/denyhost.host_http.log.XXXXXX)
+	grep ${IP} ${HTTP_FILTERED_LOG} > ${HTTP_HOST_LOG}
+
+	SSH_HOST_LOG=$(mktemp ${TMP_DIR}/denyhost.host_ssh.log.XXXXXX)
+	grep ${IP} ${SSH_FILTERED_LOG} > ${SSH_HOST_LOG}
+	LOGINS=$(gsed -n "s/.*sshd\[[0-9]\+\]: \(Invalid user\|Failed password for\( invalid user\)\?\) \([^[:space:]]\+\) from.*/\3/p" ${SSH_HOST_LOG} | \
+		sort | uniq | gsed ':a N;s/\n/, /g; ta')
+
+	if [ -z "${ABUSE}" ]; then
+		NETS=$(gsed -n "s/.*\(NET-[-0-9]\+\).*/\1/p" ${WHOIS_FILE})
+		for NET in ${NETS}; do
+			whois ${NET} >> ${WHOIS_FILE}
 		done
-		ABUSE=`extract_email $WHOIS_FILE`
+		ABUSE=$(extract_email ${WHOIS_FILE})
 	fi
 
-	if [ -z "$ABUSE" ]; then
+	if [ -z "${ABUSE}" ]; then
 		DEST_ADDR="${LOCAL_ADDR}"
-		SUBJECT="Host $IP (admin unknown) is compromised"
+		SUBJECT="Host ${IP} (admin unknown) is compromised"
 	else
-		DEST_ADDR="$ABUSE"
-		CC="-c $LOCAL_ADDR"
-		SUBJECT="Host $IP is compromised"
+		DEST_ADDR="${ABUSE}"
+		CC="-c ${LOCAL_ADDR}"
+		SUBJECT="Host ${IP} is compromised"
 	fi
 		(
-	if [ -n "$ABUSE" ]; then
+	if [ -n "${ABUSE}" ]; then
 		cat << EOF
 Greetings,
 
@@ -85,7 +85,7 @@ Greetings,
 <shtrom-admin@ssji.net> ]
 
 Unauthorised login attempts have recently been observed from an IP address
-in one of your administrative ranges ($IP), as identified by WHOIS
+in one of your administrative ranges (${IP}), as identified by WHOIS
 information.
 
 Please find below reports from the blocking system, including logs of
@@ -96,23 +96,23 @@ message to its administrator in charge.
 
 EOF
 	fi
-	echo "Offending IP: $IP"
-	echo "Hostnames: $HOSTS"
-	echo "Abuse addresses: $ABUSE"
-	echo "Usernames tried: $LOGINS"
+	echo "Offending IP: ${IP}"
+	echo "Hostnames: ${HOSTS}"
+	echo "Abuse addresses: ${ABUSE}"
+	echo "Usernames tried: ${LOGINS}"
 	echo
 	echo "Host and WHOIS information:"
-	cat $HOST_FILE
-	cat $WHOIS_FILE
+	cat ${HOST_FILE}
+	cat ${WHOIS_FILE}
 	echo
 	echo "Incriminating logs (HTTP):"
-	cat $HTTP_HOST_LOG
+	cat ${HTTP_HOST_LOG}
 	echo
 	echo "Incriminating logs (SSH):"
-	cat $SSH_HOST_LOG
-	) | $MAIL ${CC} -s "${SUBJECT}" $DEST_ADDR
+	cat ${SSH_HOST_LOG}
+	) | ${MAIL} ${CC} -s "${SUBJECT}" ${DEST_ADDR}
 
-	rm -f $HOST_FILE $WHOIS_FILE $SSH_HOST_LOG $HTTP_HOST_LOG
+	rm -f ${HOST_FILE} ${WHOIS_FILE} ${SSH_HOST_LOG} ${HTTP_HOST_LOG}
 }
 
 function extract_email
@@ -134,7 +134,7 @@ function extract_email
 		sort | uniq | gsed ':a N;s/\n/, /g; ta'
 }
 
-NEW_BLOCKERS_FILE=`mktemp ${TMP_DIR}/denyhost.blockers.list.XXXXXX`
+NEW_BLOCKERS_FILE=$(mktemp ${TMP_DIR}/denyhost.blockers.list.XXXXXX)
 
 # HTTP exploiters
 grep ${HTTP_PATTERN} ${HTTP_LOG} \
@@ -144,7 +144,7 @@ grep ${HTTP_PATTERN} ${HTTP_LOG} \
 	> ${NEW_BLOCKERS_FILE}
 
 # SSH exploiters
-SSH_FILTERED_LOG=`mktemp ${TMP_DIR}/denyhost.ssh.log.XXXXXX`
+SSH_FILTERED_LOG=$(mktemp ${TMP_DIR}/denyhost.ssh.log.XXXXXX)
 	> ${SSH_FILTERED_LOG}
 gsed -n " \
 		/Received disconnect/d; \
@@ -152,15 +152,15 @@ gsed -n " \
 		" ${SSH_LOG} \
 	| sort \
 	| uniq -c \
-	| gsed "/^ *[1-$authtries] */d;s/.* //" \
+	| gsed "/^ *[1-${authtries}] */d;s/.* //" \
 	>> ${NEW_BLOCKERS_FILE}
 
-for IP in `cat $NEW_BLOCKERS_FILE | sort | uniq | grep -v -f ${BLOCKERS_FILE}`; do
-	process_ip $IP
+for IP in $(cat ${NEW_BLOCKERS_FILE} | sort | uniq | grep -v -f ${BLOCKERS_FILE}); do
+	process_ip ${IP}
 done
 
 # Flush entries older than a week
-pfctl -t kiddies -T expire $EXPIRY 1>/dev/null 2>&1
+pfctl -t kiddies -T expire ${EXPIRY} 1>/dev/null 2>&1
 
 # Add new entries
 pfctl -t kiddies -Tadd -f ${NEW_BLOCKERS_FILE} 1>/dev/null 2>&1