#
# = net/ntlm.rb
#
# An NTLM Authentication Library for Ruby
#
# This code is a derivative of "dbf2.rb" written by yrock
# and Minero Aoki. You can find original code here:
# http://jp.rubyist.net/magazine/?0013-CodeReview
# -------------------------------------------------------------
# Copyright (c) 2005,2006 yrock
# 
# This program is free software.
# You can distribute/modify this program under the terms of the
# Ruby License.
#
# 2006-02-11 refactored by Minero Aoki
# -------------------------------------------------------------
#
# All protocol information used to write this code stems from
# "The NTLM Authentication Protocol" by Eric Glass. The author 
# would thank to him for this tremendous work and making it 
# available on the net.
# http://davenport.sourceforge.net/ntlm.html
# -------------------------------------------------------------
# Copyright (c) 2003 Eric Glass
#
# Permission to use, copy, modify, and distribute this document
# for any purpose and without any fee is hereby granted,
# provided that the above copyright notice and this list of
# conditions appear in all copies. 
# -------------------------------------------------------------
#
# The author also looked Mozilla-Firefox-1.0.7 source code,
# namely, security/manager/ssl/src/nsNTLMAuthModule.cpp and
# Jonathan Bastien-Filiatrault's libntlm-ruby.
# "http://x2a.org/websvn/filedetails.php?
# repname=libntlm-ruby&path=%2Ftrunk%2Fntlm.rb&sc=1"
# The latter has a minor bug in its separate_keys function.
# The third key has to begin from the 14th character of the 
# input string instead of 13th:)
#--
# $Id$
#++

require 'base64'
require 'openssl'
require 'openssl/digest'
require 'kconv'

module Net  #:nodoc:
  module NTLM

    module VERSION #:nodoc:
      MAJOR = 0
      MINOR = 1
      TINY  = 1
      STRING = [MAJOR, MINOR, TINY].join('.')
    end

    SSP_SIGN = "NTLMSSP\0"
    BLOB_SIGN = 0x00000101
    LM_MAGIC = "KGS!@\#$%"
    TIME_OFFSET = 11644473600
    MAX64 = 0xffffffffffffffff
    
    FLAGS = {
      :UNICODE              => 0x00000001,
      :OEM                  => 0x00000002,
      :REQUEST_TARGET       => 0x00000004,
  #   :UNKNOWN              => 0x00000008,
      :SIGN                 => 0x00000010,
      :SEAL                 => 0x00000020,
  #   :UNKNOWN              => 0x00000040,
      :NETWARE              => 0x00000100,
      :NTLM                 => 0x00000200,
  #   :UNKNOWN              => 0x00000400,
  #   :UNKNOWN              => 0x00000800,
      :DOMAIN_SUPPLIED      => 0x00001000,
      :WORKSTATION_SUPPLIED => 0x00002000,
      :LOCAL_CALL           => 0x00004000,
      :ALWAYS_SIGN          => 0x00008000,
      :TARGET_TYPE_DOMAIN   => 0x00010000,
      :TARGET_INFO          => 0x00800000,
      :NTLM2_KEY            => 0x00080000,
      :KEY128               => 0x20000000,
      :KEY56                => 0x80000000
    }
    
    FLAG_KEYS = FLAGS.keys.sort{|a, b| FLAGS[a] <=> FLAGS[b] }

    DEFAULT_FLAGS = {
      :TYPE1 => FLAGS[:UNICODE] | FLAGS[:OEM] | FLAGS[:REQUEST_TARGET] | FLAGS[:NTLM] | FLAGS[:ALWAYS_SIGN] | FLAGS[:NTLM2_KEY],
      :TYPE2 => FLAGS[:UNICODE],
      :TYPE3 => FLAGS[:UNICODE] | FLAGS[:REQUEST_TARGET] | FLAGS[:NTLM] | FLAGS[:ALWAYS_SIGN] | FLAGS[:NTLM2_KEY]
    }

  # module functions
    class << self
      def decode_utf16le(str)
        Kconv.kconv(swap16(str), Kconv::ASCII, Kconv::UTF16)
      end

      def encode_utf16le(str)
        swap16(Kconv.kconv(str, Kconv::UTF16, Kconv::ASCII))
      end
    
      def pack_int64le(val)
          [val & 0x00000000ffffffff, val >> 32].pack("V2")
      end
      
      def swap16(str)
        str.unpack("v*").pack("n*")
      end

      def split7(str)
        s = str.dup
        until s.empty?
          (ret ||= []).push s.slice!(0, 7)
        end
        ret
      end
    
      def gen_keys(str)
        split7(str).map{ |str7| 
          bits = split7(str7.unpack("B*")[0]).inject('')\
            {|ret, tkn| ret += tkn + (tkn.gsub('1', '').size % 2).to_s }
          [bits].pack("B*")
        }
      end
      
      def apply_des(plain, keys)
        dec = OpenSSL::Cipher::DES.new
        keys.map {|k|
          dec.key = k
          dec.encrypt.update(plain)
        }
      end
      
      def lm_hash(password)
        keys = gen_keys password.upcase.ljust(14, "\0")
        apply_des(LM_MAGIC, keys).join
      end   
      
      def ntlm_hash(password, opt = {})
        pwd = password.dup
        unless opt[:unicode]
          pwd = encode_utf16le(pwd)
        end
        OpenSSL::Digest::MD4.digest pwd
      end

      def ntlmv2_hash(user, password, target, opt={})
        ntlmhash = ntlm_hash(password, opt)
        userdomain = (user + target).upcase
        unless opt[:unicode]
          userdomain = encode_utf16le(userdomain)
        end
        OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, ntlmhash, userdomain)
      end

      # responses
      def lm_response(arg)
        begin
          hash = arg[:lm_hash]
          chal = arg[:challenge]
        rescue
          raise ArgumentError
        end
        chal = NTL::pack_int64le(chal) if chal.is_a?(Integer)
        keys = gen_keys hash.ljust(21, "\0")
        apply_des(chal, keys).join
      end
      
      def ntlm_response(arg)
        hash = arg[:ntlm_hash]
        chal = arg[:challenge]
        chal = NTL::pack_int64le(chal) if chal.is_a?(Integer)
        keys = gen_keys hash.ljust(21, "\0")
        apply_des(chal, keys).join
      end

      def ntlmv2_response(arg, opt = {})
        begin
          key = arg[:ntlmv2_hash]
          chal = arg[:challenge]
          ti = arg[:target_info]
        rescue
          raise ArgumentError
        end
        chal = NTL::pack_int64le(chal) if chal.is_a?(Integer)
        
        if opt[:client_challenge]
          cc  = opt[:client_challenge]
        else
          cc = rand(MAX64)
        end
        cc = NTLM::pack_int64le(cc) if cc.is_a?(Integer)

        if opt[:timestamp]
          ts = opt[:timestamp]
        else
          ts = Time.now.to_i
        end
        # epoch -> milsec from Jan 1, 1601
        ts = 10000000 * (ts + TIME_OFFSET)

        blob = Blob.new
        blob.timestamp = ts
        blob.challenge = cc
        blob.target_info = ti
        
        bb = blob.serialize
        OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, key, chal + bb) + bb
      end
      
      def lmv2_response(arg, opt = {})
        key = arg[:ntlmv2_hash]
        chal = arg[:challenge]
        
        chal = NTLM::pack_int64le(chal) if chal.is_a?(Integer)

        if opt[:client_challenge]
          cc  = opt[:client_challenge]
        else
          cc = rand(MAX64)
        end
        cc = NTLM::pack_int64le(cc) if cc.is_a?(Integer)

        OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, key, chal + cc) + cc
      end
      
      def ntlm2_session(arg, opt = {})
        begin
          passwd_hash = arg[:ntlm_hash]
          chal = arg[:challenge]
        rescue
          raise ArgumentError
        end

        if opt[:client_challenge]
          cc  = opt[:client_challenge]
        else
          cc = rand(MAX64)
        end
        cc = NTLM::pack_int64le(cc) if cc.is_a?(Integer)

        keys = gen_keys passwd_hash.ljust(21, "\0")
        session_hash = OpenSSL::Digest::MD5.digest(chal + cc).slice(0, 8)
        response = apply_des(session_hash, keys).join
        [cc.ljust(24, "\0"), response]
      end
    end


    # base classes for primitives
    class Field
      attr_accessor :active, :value

      def initialize(opts)
        @value  = opts[:value]
        @active = opts[:active].nil? ? true : opts[:active]
      end
      
      def size
        @active ? @size : 0
      end
    end

    class String < Field
      def initialize(opts)
        super(opts)
        @size = opts[:size]
      end
      
      def parse(str, offset=0)
        if @active and str.size >= offset + @size
          @value = str[offset, @size]
          @size
        else
          0
        end
      end
      
      def serialize
        if @active
          @value
        else
          ""
        end
      end
      
      def value=(val)
        @value = val
        @size = @value.nil? ? 0 : @value.size
        @active = (@size > 0)
      end
    end


    class Int16LE < Field
      def initialize(opt)
        super(opt)
        @size = 2
      end
      def parse(str, offset=0)
        if @active and str.size >= offset + @size
          @value = str[offset, @size].unpack("v")[0]
          @size
        else
          0
        end
      end
      
      def serialize
        [@value].pack("v")
      end
    end

    class Int32LE < Field
      def initialize(opt)
        super(opt)
        @size = 4
      end

      def parse(str, offset=0)
        if @active and str.size >= offset + @size
          @value = str.slice(offset, @size).unpack("V")[0]
          @size
        else
          0
        end
      end

      def serialize
        [@value].pack("V") if @active
      end
    end

    class Int64LE < Field
      def initialize(opt)
        super(opt)
        @size = 8
      end

      def parse(str, offset=0)
        if @active and str.size >= offset + @size
          d, u = str.slice(offset, @size).unpack("V2")
          @value = (u * 0x100000000 + d)
          @size
        else
          0
        end
      end
      
      def serialize
        [@value & 0x00000000ffffffff, @value >> 32].pack("V2") if @active
      end
    end

    # base class of data structure
    class FieldSet
      class << FieldSet
        def define(&block)
          c = Class.new(self)
          def c.inherited(subclass)
            proto = @proto
            subclass.instance_eval {
              @proto = proto
            }
          end
          c.module_eval(&block)
          c
        end
        
        def string(name, opts)
          add_field(name, String, opts)
        end
        
        def int16LE(name, opts)
          add_field(name, Int16LE, opts)
        end

        def int32LE(name, opts)
          add_field(name, Int32LE, opts)
        end

        def int64LE(name, opts)
          add_field(name, Int64LE, opts)
        end
        
        def security_buffer(name, opts)
          add_field(name, SecurityBuffer, opts)
        end

        def prototypes
          @proto
        end
        
        def names
          @proto.map{|n, t, o| n}
        end

        def types
          @proto.map{|n, t, o| t}
        end
        
        def opts
          @proto.map{|n, t, o| o}
        end
        
        private
        
        def add_field(name, type, opts)
          (@proto ||= []).push [name, type, opts]
          define_accessor name
        end
        
        def define_accessor(name)
          module_eval(<<-End, __FILE__, __LINE__ + 1)
          def #{name}
            self['#{name}'].value
          end
            
          def #{name}=(val)
            self['#{name}'].value = val
          end
          End
        end 
      end
      
      def initialize
        @alist = self.class.prototypes.map{ |n, t, o| [n, t.new(o)] }
      end
      
      def serialize
        @alist.map{|n, f| f.serialize }.join
      end
      
      def parse(str, offset=0)
        @alist.inject(offset){|cur, a|  cur += a[1].parse(str, cur)}
      end

      def size
        @alist.inject(0){|sum, a| sum += a[1].size}
      end

      def [](name)
        a = @alist.assoc(name.to_s.intern)
        raise ArgumentError, "no such field: #{name}" unless a
        a[1]
      end
      
      def []=(name, val)
        a = @alist.assoc(name.to_s.intern)
        raise ArgumentError, "no such field: #{name}" unless a
        a[1] = val
      end
      
      def enable(name)
        self[name].active = true
      end
      
      def disable(name)
        self[name].active = false
      end
    end


    Blob = FieldSet.define {
      int32LE    :blob_signature,   {:value => BLOB_SIGN}
      int32LE    :reserved,         {:value => 0}
      int64LE    :timestamp,      {:value => 0}
      string     :challenge,      {:value => "", :size => 8}
      int32LE    :unknown1,     {:value => 0}
      string     :target_info,      {:value => "", :size => 0}
      int32LE    :unknown2,         {:value => 0}
    }

    SecurityBuffer = FieldSet.define {
      int16LE   :length,        {:value => 0}
      int16LE   :allocated,     {:value => 0}
      int32LE   :offset,        {:value => 0}
    }

    class SecurityBuffer
      attr_accessor :active
      def initialize(opts)
        super()
        @value  = opts[:value]
        @active = opts[:active].nil? ? true : opts[:active]
        @size = 8
      end
      
      def parse(str, offset=0)
        if @active and str.size >= offset + @size
          super(str, offset)
          @value = str[self.offset, self.length]
          @size
        else
          0
        end
      end
      
      def serialize
        super if @active
      end
      
      def value
        @value
      end
      
      def value=(val)
        @value = val
        self.length = self.allocated = val.size
      end
      
      def data_size
        @active ? @value.size : 0
      end
    end
    
    class Message < FieldSet
      class << Message
        def parse(str)
          m = Type0.new
          m.parse(str)
          case m.type
          when 1
            t = Type1.parse(str)
          when 2
            t = Type2.parse(str)
          when 3
            t = Type3.parse(str)
          else
            raise ArgumentError, "unknown type: #{m.type}"
          end
          t
        end
        
        def decode64(str)
          parse(Base64.decode64(str))
        end
      end
      
      def has_flag?(flag)
        (self[:flag].value & FLAGS[flag]) == FLAGS[flag]
      end
      
      def set_flag(flag)
        self[:flag].value  |= FLAGS[flag]
      end
      
      def dump_flags
        FLAG_KEYS.each{ |k| print(k, "=", flag?(k), "\n") }
      end
      
      def serialize
        deflag
        super + security_buffers.map{|n, f| f.value}.join
      end
      
      def encode64
        Base64.encode64(serialize).gsub(/\n/, '')
      end
      
      def decode64(str)
        parse(Base64.decode64(str))
      end
      
      alias head_size size

      def data_size
        security_buffers.inject(0){|sum, a| sum += a[1].data_size}
      end

      def size
        head_size + data_size
      end
      

      private

      def security_buffers
        @alist.find_all{|n, f| f.instance_of?(SecurityBuffer)}
      end
      
      def deflag
        security_buffers.inject(head_size){|cur, a|
          a[1].offset = cur
          cur += a[1].data_size
        }
      end
      
      def data_edge
        security_buffers.map{ |n, f| f.active ? f.offset : size}.min
      end

      # sub class definitions
      
      Type0 = Message.define {
        string        :sign,      {:size => 8, :value => SSP_SIGN}
        int32LE       :type,      {:value => 0}
      }
      
      Type1 = Message.define {
        string          :sign,         {:size => 8, :value => SSP_SIGN}
        int32LE         :type,         {:value => 1}
        int32LE         :flag,         {:value => DEFAULT_FLAGS[:TYPE1] }
        security_buffer :domain,       {:value => "", :active => false}
        security_buffer :workstation,  {:value => "", :active => false}
        string          :padding,      {:size => 0, :value => "", :active => false }
      }

      class Type1
        class << Type1
          def parse(str)
            t = new
            t.parse(str)
            t
          end
        end
        
        def parse(str)
          super(str)
          enable(:domain) if has_flag?(:DOMAIN_SUPPLIED)
          enable(:workstation) if has_flag?(:WORKSTATION_SUPPLIED)
          super(str)
          if ( (len = data_edge - head_size) > 0)
            self.padding = "\0" * len
            super(str)
          end
        end
      end
      
      Type2 = Message.define{
        string        :sign,         {:size => 8, :value => SSP_SIGN}
        int32LE       :type,      {:value => 2}
        security_buffer   :target_name,  {:size => 0, :value => ""}
        int32LE       :flag,         {:value => DEFAULT_FLAGS[:TYPE2]}
        int64LE           :challenge,    {:value => 0}
        int64LE           :context,      {:value => 0, :active => false}
        security_buffer   :target_info,  {:value => "", :active => false}
        string        :padding,   {:size => 0, :value => "", :active => false }
      }
      
      class Type2
        class << Type2
          def parse(str)
            t = new
            t.parse(str)
            t
          end
        end
        
        def parse(str)
          super(str)
          if has_flag?(:TARGET_INFO)
            enable(:context)
            enable(:target_info)
            super(str)
          end
          if ( (len = data_edge - head_size) > 0)
            self.padding = "\0" * len
            super(str)
          end
        end
        
        def response(arg, opt = {})
          usr = arg[:user]
          pwd = arg[:password]
          if usr.nil? or pwd.nil?
            raise ArgumentError, "user and password have to be supplied"
          end
          
          if opt[:workstation]
            ws = opt[:workstation]
          else
            ws = ""
          end
          
          if opt[:client_challenge]
            cc  = opt[:client_challenge]
          else
            cc = rand(MAX64)
          end
          cc = NTLM::pack_int64le(cc) if cc.is_a?(Integer)
          opt[:client_challenge] = cc

          if has_flag?(:OEM) and opt[:unicode]
            usr = NTLM::decode_utf16le(usr)
            pwd = NTLM::decode_utf16le(pwd)
            ws  = NTLM::decode_utf16le(ws)
            opt[:unicode] = false
          end

          if has_flag?(:UNICODE) and !opt[:unicode]
            usr = NTLM::encode_utf16le(usr)
            pwd = NTLM::encode_utf16le(pwd)
            ws  = NTLM::encode_utf16le(ws)
            opt[:unicode] = true
          end

          tgt = self.target_name
          ti = self.target_info

          chal = self[:challenge].serialize
          
          if opt[:ntlmv2]
            ar = {:ntlmv2_hash => NTLM::ntlmv2_hash(usr, pwd, tgt, opt), :challenge => chal, :target_info => ti}
            lm_res = NTLM::lmv2_response(ar, opt)
            ntlm_res = NTLM::ntlmv2_response(ar, opt)
          elsif has_flag?(:NTLM2_KEY)
            ar = {:ntlm_hash => NTLM::ntlm_hash(pwd, opt), :challenge => chal}
            lm_res, ntlm_res = NTLM::ntlm2_session(ar, opt)
          else
            lm_res = NTLM::lm_response(pwd, chal)
            ntlm_res = NTLM::ntlm_response(pwd, chal)
          end
          
          Type3.create({
          	:lm_response => lm_res,
          	:ntlm_response => ntlm_res,
          	:domain => tgt,
            :user => usr,
            :workstation => ws,
            :flag => self.flag
          })
        end
      end
      
            
      Type3 = Message.define{
        string          :sign,          {:size => 8, :value => SSP_SIGN}
        int32LE         :type,          {:value => 3}
        security_buffer :lm_response,   {:value => ""}
        security_buffer :ntlm_response, {:value => ""}
        security_buffer :domain,        {:value => ""}
        security_buffer :user,          {:value => ""}
        security_buffer :workstation,   {:value => ""}
        security_buffer :session_key,   {:value => "", :active => false }
        int64LE         :flag,          {:value => 0, :active => false }
      }
      
      class Type3
        class << Type3
          def parse(str)
            t = new
            t.parse(str)
            t
          end
        
          def create(arg, opt ={})
            t = new
            t.lm_response = arg[:lm_response]
            t.ntlm_response = arg[:ntlm_response]
            t.domain = arg[:domain]
            t.user = arg[:user]
            t.workstation = arg[:workstation]
            
            if arg[:session_key]
              t.enable(:session_key)
              t.session_key = arg[session_key]
            end
            if arg[:flag]
              t.enable(:session_key)
              t.enable(:flag)
              t.flag = arg[:flag]
            end
            t
          end
        end
      end
    end
  end
end