Class: Rex::Post::Meterpreter::Extensions::Stdapi::Railgun::MultiCaller

Inherits:
Object
  • Object
show all
Includes:
DLLHelper
Defined in:
lib/rex/post/meterpreter/extensions/stdapi/railgun/multicall.rb

Overview

A easier way to call multiple functions in a single request

Instance Method Summary collapse

Methods included from DLLHelper

#asciiz_to_str, #assemble_buffer, #param_to_number, #str_to_ascii_z, #str_to_uni_z, #uniz_to_str

Constructor Details

#initialize(client, parent) ⇒ MultiCaller

Returns a new instance of MultiCaller.



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# File 'lib/rex/post/meterpreter/extensions/stdapi/railgun/multicall.rb', line 44

def initialize( client, parent )
	@parent = parent
	@client = client

	if( @client.platform =~ /x64/i )
		@native = 'Q'
	else
		@native = 'V'
	end
end

Instance Method Details

#call(functions) ⇒ Object 



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# File 'lib/rex/post/meterpreter/extensions/stdapi/railgun/multicall.rb', line 55

def call(functions)

	request = Packet.create_request('stdapi_railgun_api_multi')
	function_results = []
	layouts          = []
	functions.each do |f|
		dll_name,funcname,args = f
		dll_host = @parent.get_dll( dll_name )

		if not dll_host
			raise "DLL #{dll_name} has not been loaded"
		end

		function = dll_host.functions[funcname]
		if not function
			raise "DLL #{dll_name} function #{funcname} has not been defined"
		end

		raise "#{function.params.length} arguments expected. #{args.length} arguments provided." unless args.length == function.params.length
		#puts "process_function_call(function.windows_name,#{PP.pp(args, "")})"

		# We transmit the immediate stack and three heap-buffers:
		# in, inout and out. The reason behind the separation is bandwidth.
		# We don't want to transmit uninitialized data in or no-longer-needed data out.

		# out-only-buffers that are ONLY transmitted on the way BACK
		out_only_layout = {} # paramName => BufferItem
		out_only_size_bytes = 0
		#puts " assembling out-only buffer"
		function.params.each_with_index do |param_desc, param_idx|
			#puts " processing #{param_desc[1]}"

			# Special case:
			# The user can choose to supply a Null pointer instead of a buffer
			# in this case we don't need space in any heap buffer
			if param_desc[0][0,1] == 'P' # type is a pointer
				if args[param_idx] == nil
					next
				end
			end

			# we care only about out-only buffers
			if param_desc[2] == "out"
				raise "error in param #{param_desc[1]}: Out-only buffers must be described by a number indicating their size in bytes " unless args[param_idx].class == Fixnum
				buffer_size = args[param_idx]
				# bump up the size for an x64 pointer
				if( @native == 'Q' and buffer_size == 4 )
					args[param_idx] = 8
					buffer_size = args[param_idx]
				end
				
				if( @native == 'Q' )
					raise "Please pass 8 for 'out' PDWORDS, since they require a buffer of size 8" unless buffer_size == 8
				elsif( @native == 'V' )
					raise "Please pass 4 for 'out' PDWORDS, since they require a buffer of size 4" unless buffer_size == 4
				end

				out_only_layout[param_desc[1]] = BufferItem.new(param_idx, out_only_size_bytes, buffer_size, param_desc[0])
				out_only_size_bytes += buffer_size
			end
		end

		tmp = assemble_buffer("in", function, args)
		in_only_layout = tmp[0]
		in_only_buffer = tmp[1]

		tmp = assemble_buffer("inout", function, args)
		inout_layout = tmp[0]
		inout_buffer = tmp[1]


		# now we build the stack
		# every stack dword will be described by two dwords:
		# first dword describes second dword:
		#	0 - literal,
		#	1 = relative to in-only buffer
		#	2 = relative to out-only buffer
		#	3 = relative to inout buffer

		# (literal numbers and pointers to buffers we have created)
		literal_pairs_blob = ""
		#puts " assembling literal stack"
		function.params.each_with_index do |param_desc, param_idx|
			#puts "  processing (#{param_desc[0]}, #{param_desc[1]}, #{param_desc[2]})"
			buffer = nil
			# is it a pointer to a buffer on our stack
			if ["PDWORD", "PWCHAR", "PCHAR", "PBLOB"].include? param_desc[0]
				#puts "   pointer"
				if args[param_idx] == nil # null pointer?
					buffer = [0].pack(@native) # type: DWORD  (so the dll does not rebase it)
					buffer += [0].pack(@native) # value: 0
				elsif param_desc[2] == "in"
					buffer = [1].pack(@native)
					buffer += [in_only_layout[param_desc[1]].addr].pack(@native)
				elsif param_desc[2] == "out"
					buffer = [2].pack(@native)
					buffer += [out_only_layout[param_desc[1]].addr].pack(@native)
				elsif param_desc[2] == "inout"
					buffer = [3].pack(@native)
					buffer += [inout_layout[param_desc[1]].addr].pack(@native)
				else
					raise "unexpected direction"
				end
			else
				#puts "   not a pointer"
				# it's not a pointer
				buffer = [0].pack(@native)
				case param_desc[0]
					when "LPVOID", "HANDLE"
						num     = param_to_number(args[param_idx])
						buffer += [num].pack(@native)
					when "DWORD"
						num     = param_to_number(args[param_idx])
						buffer += [num % 4294967296].pack(@native)
					when "WORD"
						num     = param_to_number(args[param_idx])
						buffer += [num % 65536].pack(@native)
					when "BYTE"
						num     = param_to_number(args[param_idx])
						buffer += [num % 256].pack(@native)
					when "BOOL"
						case args[param_idx]
							when true
								buffer += [1].pack('V')
							when false
								buffer += [0].pack('V')
							else
								raise "param #{param_desc[1]}: true or false expected"
						end
					else
						raise "unexpected type for param #{param_desc[1]}"
				end
			end

			#puts "   adding pair to blob"
			literal_pairs_blob += buffer
			#puts "   buffer size %X" % buffer.length
			#puts "   blob size so far: %X" % literal_pairs_blob.length
		end

		#puts "\n\nsending Stuff to meterpreter"

		group = Rex::Post::Meterpreter::GroupTlv.new(TLV_TYPE_RAILGUN_MULTI_GROUP)
		group.add_tlv(TLV_TYPE_RAILGUN_SIZE_OUT, out_only_size_bytes)
		group.add_tlv(TLV_TYPE_RAILGUN_STACKBLOB, literal_pairs_blob)
		group.add_tlv(TLV_TYPE_RAILGUN_BUFFERBLOB_IN, in_only_buffer)
		group.add_tlv(TLV_TYPE_RAILGUN_BUFFERBLOB_INOUT, inout_buffer)
		group.add_tlv(TLV_TYPE_RAILGUN_DLLNAME, dll_name )
		group.add_tlv(TLV_TYPE_RAILGUN_FUNCNAME, function.windows_name)
		request.tlvs << group

		layouts << [inout_layout, out_only_layout]
	end

	call_results = []
	res = @client.send_request(request)
	res.each(TLV_TYPE_RAILGUN_MULTI_GROUP) do |val|
		call_results << val
	end

	functions.each do |f|
		dll_name,funcname,args = f
		dll_host = @parent.get_dll( dll_name )
		function = dll_host.functions[funcname]
		response = call_results.shift
		inout_layout, out_only_layout = layouts.shift

		rec_inout_buffers = response.get_tlv_value(TLV_TYPE_RAILGUN_BACK_BUFFERBLOB_INOUT)
		rec_out_only_buffers = response.get_tlv_value(TLV_TYPE_RAILGUN_BACK_BUFFERBLOB_OUT)
		rec_return_value = response.get_tlv_value(TLV_TYPE_RAILGUN_BACK_RET)
		rec_last_error = response.get_tlv_value(TLV_TYPE_RAILGUN_BACK_ERR)

		# The hash the function returns
		return_hash={"GetLastError" => rec_last_error}

		#process return value
		case function.return_type
			when "LPVOID", "HANDLE"
				if( @native == 'Q' )
					return_hash["return"] = rec_return_value
				else
					return_hash["return"] = rec_return_value % 4294967296
				end
			when "DWORD"
				return_hash["return"] = rec_return_value % 4294967296
			when "WORD"
				return_hash["return"] = rec_return_value % 65536
			when "BYTE"
				return_hash["return"] = rec_return_value % 256
			when "BOOL"
				return_hash["return"] = (rec_return_value != 0)
			when "VOID"
				return_hash["return"] = nil
			else
				raise "unexpected return type: #{function.return_type}"
		end
		#puts return_hash
		#puts "out_only_layout:"
		#puts out_only_layout


		# process out-only buffers
		#puts "processing out-only buffers:"
		out_only_layout.each_pair do |param_name, buffer_item|
			#puts "   #{param_name}"
			buffer = rec_out_only_buffers[buffer_item.addr, buffer_item.length_in_bytes]
			case buffer_item.datatype
				when "PDWORD"
					return_hash[param_name] = buffer.unpack('V')[0]
				when "PCHAR"
					return_hash[param_name] = asciiz_to_str(buffer)
				when "PWCHAR"
					return_hash[param_name] = uniz_to_str(buffer)
				when "PBLOB"
					return_hash[param_name] = buffer
				else
					raise "unexpected type in out-only buffer of #{param_name}: #{buffer_item.datatype}"
			end
		end
		#puts return_hash

		# process in-out buffers
		#puts "processing in-out buffers:"
		inout_layout.each_pair do |param_name, buffer_item|
			#puts "   #{param_name}"
			buffer = rec_inout_buffers[buffer_item.addr, buffer_item.length_in_bytes]
			case buffer_item.datatype
				when "PDWORD"
					return_hash[param_name] = buffer.unpack('V')[0]
				when "PCHAR"
					return_hash[param_name] = asciiz_to_str(buffer)
				when "PWCHAR"
					return_hash[param_name] = uniz_to_str(buffer)
				when "PBLOB"
					return_hash[param_name] = buffer
				else
					raise "unexpected type in in-out-buffer of #{param_name}: #{buffer_item.datatype}"
			end
		end
		#puts return_hash
		#puts "finished"

		function_results << return_hash
	end
	function_results
end