ronin-rb/ronin-support

# frozen_string_literal: true
#
# Copyright (c) 2006-2023 Hal Brodigan (postmodern.mod3 at gmail.com)
#
# ronin-support is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# ronin-support is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with ronin-support.  If not, see <https://www.gnu.org/licenses/>.
#

require 'ronin/support/network/dns/idn'

begin
  require 'net/pop'
rescue LoadError => error
  warn "ronin/network/pop3 requires the net-pop gem be listed in the Gemfile."
  raise(error)
end

module Ronin
  module Support
    module Network
      module POP3
        #
        # Provides helper methods for communicating with POP3 services.
        #
        module Mixin
          # Default POP3 port
          DEFAULT_PORT = 110

          #
          # Creates a connection to the POP3 server.
          #
          # @param [String] host
          #   The host to connect to.
          #
          # @param [Integer] port
          #   The port the POP3 server is running on.
          #
          # @param [Boolean, Hash] ssl
          #   Additional SSL options.
          #
          # @option ssl [Boolean] :verify
          #   Specifies that the SSL certificate should be verified.
          #
          # @option ssl [String] :certs
          #   The path to the file containing CA certs of the server.
          #
          # @param [String] user
          #   The user to authenticate with when connecting to the POP3 server.
          #
          # @param [String] password
          #   The password to authenticate with when connecting to the POP3
          #   server.
          #
          # @yield [pop3]
          #   If a block is given, it will be passed the newly created POP3
          #   session. Once the block returns the POP3 session will be closed.
          #
          # @yieldparam [Net::POP3] pop3
          #   The newly created POP3 session.
          #
          # @return [Net::POP3, nil]
          #   The newly created POP3 session. If a block is given, `nil` will be
          #   returned.
          #
          # @api public
          #
          def pop3_connect(host, port: DEFAULT_PORT,
                                 ssl:  nil,
                                 user: ,
                                 password: )
            host = DNS::IDN.to_ascii(host)

            case ssl
            when Hash
              ssl        = true
              ssl_certs  = ssl[:certs]
              ssl_verify = SSL::VERIFY[ssl[:verify]]
            when TrueClass
              ssl        = true
              ssl_certs  = nil
              ssl_verify = nil
            else
              ssl        = false
              ssl_certs  = nil
              ssl_verify = false
            end

            pop3 = Net::POP3.new(host,port)
            pop3.enable_ssl(ssl_verify,ssl_certs) if ssl
            pop3.start(user,password)

            if block_given?
              begin
                yield pop3
              ensure
                pop3.finish
              end
            else
              return pop3
            end
          end
        end
      end
    end
  end
end