packet filter assistance script

Signed-off-by: Georg <georg@lysergic.dev>

scripts/sh/pf.sh

@@ -0,0 +1,129 @@
+#!/bin/sh
+# 
+# Helps you edit a production packet filter configuration and reduces the risk of doing something really bad.
+# 
+# Author: Georg Pfuetzenreuter <georg@lysergic.dev>
+# Last edit: 02/11/2021
+#
+# This assumes .ssh/config being configured to ssh into your router with a user having write access to /tmp/* and $prodfile as well as having doas permissions for `pfctl -f $prodfile`.
+
+editor="$(which vim)"
+prodfile="/etc/pf.conf"
+backupfile="/tmp/pf.conf.bak-$(date -u +%d%m%y-%H%M)"
+stagefile="/tmp/pf.conf-work-$USER-$(date -u +%d%m%y-%H%M)"
+
+gethostaddress () {
+        ssh -G "$host" |grep hostname |awk '{print $2}' |head -n1
+}
+
+init () {
+        hostaddress=$(gethostaddress)
+        if nc -nz $hostaddress 22 2>/dev/null; then
+                workfile="/tmp/pf.conf.$host-$USER-$(date -u +%d%m%y-%H%M)"
+                ssh -q $host cp $prodfile $backupfile
+                scp -q $host:$prodfile $workfile
+                edit
+        else
+                echo "Host not reachable."
+        fi
+}
+
+
+edit () {
+        if [ ! -f "$workfile" ]; then
+                echo "Could not create workfile."
+                exit 1
+        else
+                $editor "$workfile"
+                scp -q $workfile $host:$stagefile
+                check
+        fi
+}
+
+check () {
+        echo "$stagefile"
+        ssh -q $host pfctl -nf $stagefile
+        result="$?"
+        case $result in
+                0 ) edit_ok
+                ;;
+                1 ) edit_failed
+                ;;
+                * ) echo "$result - Unhandled condition. Aborting." && exit 1
+                ;;
+        esac
+}
+
+edit_ok () {
+        echo "Syntax OK. Type YES to deploy changes or anything else to abort."
+        read choice
+        if [ "$choice" = "YES" ]; then
+                deploy
+        else
+                #rollback
+                abort
+        fi
+}
+
+edit_failed () {
+        echo "Syntax error. [e]dit or [a]bort?"
+        read choice
+        if [ "$choice" = "e" ]; then
+                edit
+        elif [ "$choice" = "a" ]; then
+                abort
+                echo "OK. Exiting."
+        else
+                echo "Invalid choice. Let's try this again."
+                edit_failed
+        fi
+}
+
+abort () {
+        rm $workfile
+        ssh -q $host rm $stagefile
+}
+
+rollback () {
+        ssh -q $host cp $backupfile $prodfile
+        ssh -q $host pfctl -nf $prodfile
+        result="$?"
+        case $result in
+                0 ) echo "Rollback ok." && exit
+                ;;
+                1 ) echo "Rollback failed. You NEED to investigate this."
+                ;;
+                * ) echo "Unhandled rollback return code. Investigate this!"
+                ;;
+        esac
+
+}
+
+deploy () {
+        ssh -q $host cp $stagefile $prodfile
+        ssh -q $host pfctl -nf $prodfile
+        result="$?"
+        case $result in
+                0 )
+                ssh -q $host doas pfctl -f $prodfile
+                echo "OK."
+                ssh -q $host rm $stagefile
+                rm $workfile
+                ;;
+                1 )
+                echo "Deployment failed. Initiating rollback."
+                rollback
+                ;;
+                * ) echo "Unhandled condition. Investigate this! Initiating rollback."
+                rollback
+                ;;
+        esac
+}
+
+if [ -z "$1" ]; then
+        echo "Missing argument. Specify a host."
+        exit 1
+else
+        host="$1"
+        init
+fi