#
# Copyright (c) 2006-2018 Wade Alcorn - wade@bindshell.net
# Browser Exploitation Framework (BeEF) - http://beefproject.com
# See the file 'doc/COPYING' for copying permission
#

# Remove Thin 'Server' response header
Thin.send :remove_const, :SERVER
Thin::SERVER = nil

module BeEF
  module Core
    class Server
      include Singleton

      # @note Grabs the version of beef the framework is deployed on
      VERSION = BeEF::Core::Configuration.instance.get('beef.version')

      attr_reader :root_dir, :url, :configuration, :command_urls, :mounts, :semaphore

      def initialize
        @configuration = BeEF::Core::Configuration.instance
        beef_proto = configuration.get("beef.http.https.enable") == true ? "https" : "http"
        beef_host = @configuration.get("beef.http.public") || @configuration.get("beef.http.host")
        beef_port = @configuration.get("beef.http.public_port") || @configuration.get("beef.http.port")
        @url = "#{beef_proto}://#{beef_host}:#{beef_port}"
        @root_dir = File.expand_path('../../../', __FILE__)
        @command_urls = {}
        @mounts = {}
        @rack_app
        @semaphore = Mutex.new
      end

      def to_h
        {
            'beef_version'  => VERSION,
            'beef_url'      => @url,
            'beef_root_dir' => @root_dir,
            'beef_host'     => @configuration.get('beef.http.host'),
            'beef_port'     => @configuration.get('beef.http.port'),
            'beef_public'   => @configuration.get('beef.http.public'),
            'beef_public_port' => @configuration.get('beef.http.public_port'),
            'beef_hook'     => @configuration.get('beef.http.hook_file'),
            'beef_proto'    => @configuration.get('beef.http.https.enable') == true ? 'https' : 'http',
            'client_debug'  => @configuration.get('beef.client_debug')
        }
      end

      #
      # Mounts a handler, can either be a hard or soft mount
      #
      # @param [String] url The url to mount
      # @param [Class] http_handler_class Class to call once mount is triggered
      # @param args Arguments to pass to the http handler class
      #
      def mount(url, http_handler_class, args = nil)
        # argument type checking
        raise Exception::TypeError, '"url" needs to be a string' unless url.string?

        if args.nil?
          @mounts[url] = http_handler_class
        else
          @mounts[url] = http_handler_class, *args
        end
        print_debug "Server: mounted handler '#{url}'"
      end

      #
      # Unmounts handler
      #
      # @param [String] url URL to unmount.
      #
      def unmount(url)
        raise Exception::TypeError, '"url" needs to be a string' unless url.string?
        @mounts.delete url
      end

      #
      # Reload the URL map (used by the NetworkStack AssetHandler to mount new URLs at runtime)
      #
      def remap
        @rack_app.remap @mounts
      end

      #
      # Prepares the BeEF http server.
      #
      def prepare
        # Create http handler for the javascript hook file
        mount(@configuration.get("beef.http.hook_file").to_s, BeEF::Core::Handlers::HookedBrowsers.new)

        # Create handler for the initialization checks (Browser Details)
        mount('/init', BeEF::Core::Handlers::BrowserDetails)

        # Dynamically get the list of all the http handlers using the API and register them
        BeEF::API::Registrar.instance.fire(BeEF::API::Server, 'mount_handler', self)

        # Rack mount points
        @rack_app = Rack::URLMap.new(@mounts)

        return if @http_server

        # Set the logging level of Thin to match the config 
        Thin::Logging.silent = true
        if @configuration.get('beef.http.debug') == true
          Thin::Logging.silent = false
          Thin::Logging.debug = true
        end

        # Create the BeEF http server
        @http_server = Thin::Server.new(
          @configuration.get('beef.http.host'),
          @configuration.get('beef.http.port'),
          @rack_app)

        # Configure SSL/TLS
        return unless @configuration.get('beef.http.https.enable') == true

        openssl_version = OpenSSL::OPENSSL_VERSION
        if openssl_version =~ / 1\.0\.1([a-f])? /
          print_warning "Warning: #{openssl_version} is vulnerable to Heartbleed (CVE-2014-0160)."
          print_more 'Upgrade OpenSSL to version 1.0.1g or newer.'
        end

        cert_key = @configuration.get 'beef.http.https.key'
        unless cert_key.start_with? '/'
          cert_key = File.expand_path cert_key, $root_dir
        end
        unless File.exist? cert_key
          print_error "Error: #{cert_key} does not exist"
          exit 1
        end

        cert = @configuration.get 'beef.http.https.cert'
        unless cert.start_with? '/'
          cert = File.expand_path cert, $root_dir
        end
        unless File.exist? cert
          print_error "Error: #{cert} does not exist"
          exit 1
        end

        @http_server.ssl = true
        @http_server.ssl_options = {
          :private_key_file => cert_key,
          :cert_chain_file  => cert,
          :verify_peer      => false
        }

        if Digest::SHA256.hexdigest(File.read(cert)).eql?('ccbc5e0a998eac18c1b60bbb14b439529c26e7ea4d824172df4991c3acc49cc4') ||
           Digest::SHA256.hexdigest(File.read(cert_key)).eql?('300266e04bbda70f9f81a38d33973572d161f8d20bc8e2d6758f2bd6130f3825')
          print_warning 'Warning: Default SSL cert/key in use.'
          print_more 'Use the ./tools/generate-certificate utility to generate a new certificate.'
        end
      end

      #
      # Starts the BeEF http server
      #
      def start
        @http_server.start
      rescue RuntimeError => e
        # port is in use
        raise unless e.message.include? 'no acceptor'
        print_error "Another process is already listening on port #{@configuration.get('beef.http.port')}, or you're trying to bind BeEF to an invalid IP."
        print_error 'Is BeEF already running? Exiting...'
        exit 127
      end
    end
  end
end
