firewall-whitelist

#!/usr/bin/ruby
#
# NAME
#
#   firewall-whitelist -- Automatically whitelist IP addresses.
#
# SYNOPSIS
#
#  Options:
#
#   --prefix      The directory to operate upon.
#
#  Help Options:
#
#   --help        Show the help information for this script.
#   --verbose     Show debugging information.
#
# This script is designed to automatically whitelist IP addresses which
# have been used to successfully login via SSH.
#
# It does this by parsing the output of the "last" command, and creating
# entries in /etc/symbiosis/firewall/whitelist.d/
#
# AUTHOR
#
#   Steve Kemp <steve@bytemark.co.uk>
#

#
#  Modules we require
#

require 'getoptlong'
require 'ipaddr'

opts = GetoptLong.new(
    [ '--help',    '-h', GetoptLong::NO_ARGUMENT ],
    [ '--verbose', '-v', GetoptLong::NO_ARGUMENT ],
    [ '--prefix',  '-p', GetoptLong::REQUIRED_ARGUMENT ]
)


#
#  The options set by the command line.
#
$HELP    = false
$VERBOSE = false
$PREFIX  = "/etc/symbiosis/firewall/whitelist.d"

opts.each do |opt,arg|
  case opt
    when '--help'
      $HELP = true
    when '--verbose'
      $VERBOSE = true
    when '--prefix'
      $PREFIX = arg
  end
end


#
# CAUTION! Here be quality kode.
#
if $HELP
  # Open the file, stripping the shebang line
  lines = File.open(__FILE__){|fh| fh.readlines}[2..-1]

  lines.each do |line|
    line.chomp!
    break if line.empty?
    puts line[2..-1].to_s
  end

  exit 0
end


#
#  Expire old entries first of all, then add new ones.
#
puts "Expiring old whitelist entries" if ( $VERBOSE )

expired = 0

if ( File.directory?( $PREFIX ) )
  Dir.foreach( $PREFIX ) do |entry|
    if ( ( entry =~ /\.auto$/i ) &&
         (File.mtime( "#{$PREFIX}/#{entry}" ) <  ( Time.now - 8 * 24 * 60 * 60 ) ) )
    then
      puts "Removing #{$PREFIX}/#{entry}" if ( $VERBOSE )
      File.unlink("#{$PREFIX}/#{entry}")
      expired += 1
    end
  end
end
puts "Expiring done - removed #{expired} file(s)" if ( $VERBOSE )



ip_addresses = {}


#
#  Run last to find the IPs, store unique ones in a hash.
#
IO.popen("/usr/bin/last -i") {|pipe| pipe.readlines}.each do |l|
  next unless l =~ /[ \t]((\d{1,3}\.){3,3}\d{1,3}|[0-9a-f:]+)[ \t]/
  ip_addresses[ $1 ] = 1
end


#
#  Did we update?
#
updated=false

#
#  Iterate over each IP
#
ip_addresses.each_key do |ip|
  if ( ( ip =~ /^([0-9]+)\.([0-9]+)\.([0-9]+)\.([0-9]+)$/ ) &&
       ( ip !~ /^(127|0)\./ ) )

    puts "Found IP address: #{ip}" if ( $VERBOSE )

    if ( File.exists?( "/etc/symbiosis/firewall/whitelist.d/#{ip}.auto" ) )
      puts "\tAlready whitelisted" if ( $VERBOSE )
    else
      # ensure the directory exists.
      if ( ! File.directory?( "/etc/symbiosis/firewall/whitelist.d" ) )
        system( "mkdir -p /etc/symbiosis/firewall/whitelist.d" )
      end

      # create the file
      system( "touch /etc/symbiosis/firewall/whitelist.d/#{ip}.auto" )

      updated=true
      puts "\tAdding to whitelist" if ( $VERBOSE )
    end
  end
end



#
#  Finally re-run the firewall if we updated, or if we removed
# an expired entry.
#
if ( ( updated ) || ( expired ) )

  puts "Updated whitelist, re-running firewall" if ( $VERBOSE )

  system( "/usr/bin/firewall" )
end