Class: DRab::DRabMessage

Inherits:
Object
  • Object
show all
Defined in:
lib/drab/drab.rb

Defined Under Namespace

Modules: Types

Constant Summary collapse

BLACKLISTED_BASIC_OBJECT_METHODS = 
Set.new([
    "send",
    "__send__",
    "method",
    "methods",
    "inspect",
    "private_methods",
    "protected_methods",
    "public_method",
    "public_methods",
    "public_send",
    "singleton_class",
    "singleton_method",
    "singleton_methods",
    "taint",
    "trust",
    "untaint",
    "untrust",
    "instance_eval",
    "instance_exec",
    "method_missing",
    "singleton_method_added",
    "singleton_method_removed",
    "instance_variables",
    "instance_variable_get",
    "instance_variable_set",
    "instance_variable_defined?",
    "remove_instance_variable",
])
BLACKLISTED_MODULE_METHODS = 
Set.new([
    "used_modules",
    "alias_method",
    "append_features",
    "attr",
    "attr_reader",
    "attr_accessor",
    "attr_writer",
    "define_method",
    "extend_object",
    "extended",
    "include",
    "included",
    "included_modules",
    "instance_method",
    "instance_methods",
    "module_eval",
    "module_exec",
    "prepend",
    "private_class_method",
    "private_constant",
    "private_instance_methods",
    "protected_instance_methods",
    "public_class_method",
    "public_instance_method",
    "public_instance_methods",
    "remove_class_variable",
    "constants",
    "nesting",
    "ancestors",
    "autoload",
    "class_eval",
    "class_exec",
    "class_variable_get",
    "class_variable_set",
    "class_variables",
    "const_get",
    "const_set",
    "const_missing",
    "deprecate_constants",
    "method_added",
    "method_removed",
    "method_undefined",
    "method_function",
    "prepend_features",
    "prepended",
    "private",
    "refine",
    "remove_const",
    "remove_method",
    "undef_method",
    "using",
])
BLACKLISTED_REPL_METHODS = 
Set.new([
    "pry",
    "binding",
    "__binding__",
    "remote_pry",
    "remote_pray",
    "pry_remote",
    "pray_remote"
])

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ DRabMessage

Returns a new instance of DRabMessage.



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# File 'lib/drab/drab.rb', line 180

def initialize(config)
  @load_limit = config[:load_limit]
  @argc_limit = config[:argc_limit]
end

Instance Method Details

#dump(obj, error = false, as_json = false) ⇒ Object 



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# File 'lib/drab/drab.rb', line 185

def dump(obj, error=false, as_json = false)
  if as_json
    str = JSON::dump(obj)
    return [str.size].pack('N') + str
  end

  if obj.is_a?(DRabUndumped)
    obj = make_proxy(obj, error)
  elsif obj.is_a?(Proc)
    obj = make_proxy(obj, error)        
  elsif obj.is_a?(DRabArray)
    p = dump(DRabArray::Token.new(obj.get.size), error)
    obj.get.each { |o| p += dump(o) }
    return p
  end

  begin
    str = Marshal::dump(obj)
  rescue
    #str = Marshal::dump(make_proxy(obj, error))
    STDERR.puts "failed to marshal value of type " + obj.class.to_s + ", not exposing a proxy"
    str = Marshal::dump(nil)
  end
  [str.size].pack('N') + str
end

#kill_instance_methods(obj, msg) ⇒ Object 



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# File 'lib/drab/drab.rb', line 509

def kill_instance_methods(obj, msg)
  if [ "object_id", "__id__" ].include?(msg)
    return
  end

  if obj.is_a?(DRabUndumped)
    if obj.class.class_variable_get(:@@drab_whitelist).include?("to_s")
      if msg === "respond_to?"
        return
      end
    end
    if obj.class.class_variable_get(:@@drab_whitelist).include?(msg)
      return
    else
      puts "unwhitelisted method call attempted: #{msg} on" + obj.class.to_s
      raise Exception.new("unwhitelisted method call attempted")
    end
  end
  
  if BLACKLISTED_BASIC_OBJECT_METHODS.include?(msg)
    puts "dangerous BasicObject method called: #{msg} on " + obj.class.to_s
    raise Exception.new("dangerous BasicObject method called")
  end

  if BLACKLISTED_MODULE_METHODS.include?(msg)
    puts "dangerous Module method called: #{msg} on " + obj.class.to_s
    raise Exception.new("dangerous Module method called")
  end

  if BLACKLISTED_REPL_METHODS.include?(msg)
    puts "dangerous repl method called: #{msg} on " + obj.class.to_s
    raise Exception.new("dangerous repl method called")
  end

end

#load(soc, as_json = false) ⇒ Object

Raises:



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# File 'lib/drab/drab.rb', line 211

def load(soc, as_json = false)
  begin
    sz = soc.read(4)
  rescue
    raise(DRabConnError, $!.message, $!.backtrace)
  end
  raise(DRabConnError, 'connection closed') if sz.nil?
  raise(DRabConnError, 'premature header') if sz.size < 4
  sz = sz.unpack('N')[0]
  raise(DRabConnError, "too large packet #{sz}") if @load_limit < sz
  begin
    str = soc.read(sz)
  rescue
    raise(DRabConnError, $!.message, $!.backtrace)
  end
  raise(DRabConnError, 'connection closed') if str.nil?
  raise(DRabConnError, 'premature marshal format(can\'t read)') if str.size < sz
  
  if not as_json
    begin
      typ, structure = parse_marshal(str)
    rescue Exception => e
    end
  end

  DRab.mutex.synchronize do
    begin
      save = Thread.current[:drab_untaint]
      Thread.current[:drab_untaint] = []
      if as_json
        JSON::load(str)
      else
        if typ.between?(Types::Bln, Types::Arr)
          Marshal::load(str)
        elsif typ === Types::Err
          Exception.new(s.to_s)
        else
          STDERR.puts "got weird object: " + str.inspect + "\nwith structure: " + structure.inspect
          nil
        end
      end
    rescue NameError, ArgumentError => e
      puts e
      puts e.backtrace
      DRabUnknown.new($!, str)
    ensure
      Thread.current[:drab_untaint].each do |x|
        x.untaint
      end
      Thread.current[:drab_untaint] = save
    end
  end
end

#match_structures(template, target) ⇒ Object 



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# File 'lib/drab/drab.rb', line 281

def match_structures(template, target)
  begin
    if not (template.is_a?(Array) and target.is_a?(Array))
      return false
    end

    if template.size != target.size
      return false
    end

    return (0...template.size).collect do |n|
      if template[n].is_a?(Array)
        hld = match_structures(template[n], target[n])
        if !hld
          return [false]
        else
          next hld
        end
      end

      if template[n] === target[n]
        next true
      end

      if template[n].is_a?(String) and target[n].is_a?(String)
        if template[n] === "*"
          next true
        elsif template[n].start_with?("*")
          next target[n].end_with?(template[n][1..-1])
        elsif template[n].end_with?("*")
          next target[n].start_with?(template[n][0..-2])
        else
          return [false]
        end
      end
    end.inject { |t, n| t and n }
  rescue Exception => e
    STDERR.puts e
    STDERR.puts e.backtrace
  end     
  return false
end

#parse_marshal(str) ⇒ Object 



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# File 'lib/drab/drab.rb', line 337

def parse_marshal(str)
  begin
    # i don't know why, but if this runs in the current thread,
    # the __recursive_key__ state in PP, as invoked by pry, gets mangled
    msthread = Thread.new { Thread.current[:structure] = Marshal::Structure::load(str) }
    msthread.join
    parsed_str = msthread[:structure]
    if parsed_str === :true or parsed_str === :false
      return Types::Bln
    elsif parsed_str === :nil
      return Types::Nil
    elsif parsed_str === [:symbol, 0, "write"] # :write
      return Types::Sym
    elsif parsed_str === [:symbol, 0, "readline"] # :readline
      return Types::Sym
    elsif parsed_str.size === 2 and parsed_str[0] === :fixnum and parsed_str[1].is_a?(Integer)
      return Types::Num
    elsif match_structures([ # json DRab::DRabObject
      :user_defined,
      0,
      [:symbol, 0, "DRab::DRabObject"],
      "*"
    ], parsed_str)
      return [Types::DRb, parsed_str]
    elsif match_structures([ # json DRab::DRabObject
      :instance_variables,
      [
        :user_defined,
        0,
        [:symbol, 0, "DRab::DRabObject"],
        "*"
      ],
      1,
      [:symbol, 1, "E"],
      :true
    ], parsed_str)
      return [Types::DRb, parsed_str]
    elsif match_structures([ # string
      :string,
      0,
      "*"
    ], parsed_str)
      return Types::Str
    elsif match_structures([ # string
      :instance_variables,
      [:string, 0, "*"],
      1,
      [:symbol, 0, "E"],
      :false
    ], parsed_str)
      return Types::Str
    elsif match_structures([ # json DRab::DRabArray::Token
      :instance_variables,
      [
        :user_defined,
        0,
        [:symbol, 0, "DRab::DRabArray::Token"],
        "*"
      ],
      1,
      [:symbol, 1, "E"],
      :true
    ], parsed_str)
      return [Types::Arr, parsed_str]
    elsif match_structures([
      [:object, 0, [:symbol, 0, "*Error"]]
    ], parsed_str[0..2])
      return [Types::Err, parsed_str]
    else
      return [Types::Ukn, parsed_str]
    end
  rescue Exception => e
    STDERR.puts e
    STDERR.puts e.backtrace
  end
  return [Types::Ukn, parsed_str]
end

#recv_reply(stream) ⇒ Object 



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# File 'lib/drab/drab.rb', line 636

def recv_reply(stream)
  recv_secret(stream)
  succ = load(stream)
  result = load(stream)
  if result.is_a?(DRabArray::Token)
    r = result.size.times.collect {|| load(stream) }
    [succ, r]
  else
    [succ, result]
  end
end

#recv_request(stream) ⇒ Object

/jtd

Raises:



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# File 'lib/drab/drab.rb', line 596

def recv_request(stream)
  recv_secret(stream)
  ref = load(stream, true)
  if not ref.is_a? Integer and not ref.is_a? NilClass
    raise Exception.new "non-numeric ref id"
  end
  ro = DRab.to_obj(ref)

  msg = load(stream, true)
  if not msg.is_a? String
    raise Exception.new "non-string msg name"
  end

  #note: obviously, blacklisting a few things is not enough, we also need
  #      to make sure that arbitrary objects can't just be wrapped by id
  #      or deserialized, and maybe do to limit the sorts of
  #      objects that can be passed to only primative or "DRab-aware" types.
  kill_instance_methods(ro, msg)

  argc = load(stream, true)
  if not argc.is_a? Integer
    raise Exception.new "non-numeric argc"
  end
  raise(DRabConnError, "too many arguments") if @argc_limit < argc
  argv = Array.new(argc, nil)
  argc.times do |n|
    argv[n] = load(stream)
  end
  block = nil

  return ro, msg, argv, block
end

#recv_secret(stream) ⇒ Object 



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# File 'lib/drab/drab.rb', line 565

def recv_secret(stream)
  if DRab.current_server.secret != nil
    shared_secret = DRab.current_server.secret
    received_secret = nil

    begin
      sz = stream.read(4)
    rescue
      raise(DRabConnError, $!.message, $!.backtrace)
    end
    raise(DRabConnError, 'connection closed') if sz.nil?
    raise(DRabConnError, 'secret size wrong size') if sz.size != 4
    sz = sz.unpack('N')[0]
    raise(DRabConnError, 'secret size wrong') if sz != shared_secret.size
    begin
      received_secret = stream.read(sz)
    rescue
      raise(DRabConnError, $!.message, $!.backtrace)
    end
    raise(DRabConnError, 'connection closed') if received_secret.nil?
    raise(DRabConnError, 'premature secret (can\'t read)') if received_secret.size < sz

    if received_secret.length != shared_secret.length
      stream.close
    elsif !secure_compare(shared_secret, received_secret)
      stream.close
    end
  end
end

#secure_compare(a, b) ⇒ Object

taken from rails/ActiveSupport/MessageVerifier/secure_compare



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# File 'lib/drab/drab.rb', line 555

def secure_compare(a, b)
  return false unless a.bytesize == b.bytesize

  l = a.unpack "C#{a.bytesize}"

  res = 0
  b.each_byte { |byte| res |= byte ^ l.shift }
  res == 0
end

#send_reply(stream, succ, result) ⇒ Object 



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# File 'lib/drab/drab.rb', line 629

def send_reply(stream, succ, result)
  send_secret(stream)
  stream.write(dump(succ) + dump(result, !succ))
rescue
  raise(DRabConnError, $!.message, $!.backtrace)
end

#send_request(stream, ref, msg_id, arg, b) ⇒ Object 



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# File 'lib/drab/drab.rb', line 265

def send_request(stream, ref, msg_id, arg, b)
  ary = []
  ary.push(dump(ref.__drabref, false, true))
  ary.push(dump(msg_id.id2name, false, true))
  ary.push(dump(arg.length, false, true))
  arg.each do |e|
    ary.push(dump(e))
  end
  #ary.push(dump(b))

  send_secret(stream)
  stream.write(ary.join(''))
rescue
  raise(DRabConnError, $!.message, $!.backtrace)
end

#send_secret(stream) ⇒ Object

jtd: adding symkey auth here



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# File 'lib/drab/drab.rb', line 547

def send_secret(stream)
  if DRab.current_server.secret != nil
    shared_secret = DRab.current_server.secret
    stream.write([shared_secret.size].pack('N') + shared_secret)
  end
end