fixed up encoding, made payload generation pimper

git-svn-id: file:///home/svn/incoming/trunk@2746 4d416f70-5f16-0410-b530-b9f4589650da

lib/msf/base/simple/payload.rb

@@ -19,13 +19,14 @@ class Payload
 	#
 	# opts can have:
 	#
-	#   Encoder   => A encoder module instance.
-	#   Badchars  => A string of bad characters.
-	#   Format    => The format to represent the data as: ruby, perl, c, raw
-	#   Options   => A hash of options to set.
-	#   OptionStr => A string of options in VAR=VAL form separated by
-	#                whitespace.
-	#   NoComment => Disables prepention of a comment
+	#   Encoder     => A encoder module instance.
+	#   Badchars    => A string of bad characters.
+	#   Format      => The format to represent the data as: ruby, perl, c, raw
+	#   Options     => A hash of options to set.
+	#   OptionStr   => A string of options in VAR=VAL form separated by
+	#                  whitespace.
+	#   NoComment   => Disables prepention of a comment
+	#   NopSledSize => The number of NOPs to use
 	#
 	# raises:
 	#
@@ -43,30 +44,28 @@ class Payload
 		end
 
 		# Generate the payload
-		buf = payload.generate
-
-		# If an encoder was specified, encode the generated payload
-		if (opts['Encoder'])
-			buf = opts['Encoder'].encode(buf, opts['Badchars'])
-		end
+		e = EncodedPayload.create(payload,
+				'BadChars' => opts['BadChars'],
+				'MinNops'  => opts['NopSledSize'],
+				'Encoder'  => opts['Encoder'])
 
 		fmt = opts['Format'] || 'raw'
 
 		# Save off the original payload length
-		len = buf.length
+		len = e.encoded.length
 
 		# Serialize the generated payload to some sort of format
-		buf = Buffer.transform(buf, fmt)
+		buf = Buffer.transform(e.encoded, fmt)
 
 		# Prepend a comment
 		if (fmt != 'raw' and opts['NoComment'] != true)
 			((ds = payload.datastore.to_s) and ds.length > 0) ? ds += "\n" : ds = ''
-			
 			buf = Buffer.comment(
 				"#{payload.refname} - #{len} bytes\n" +
 				"http://www.metasploit.com\n" +
 				"#{ds}" + 
-				((opts['Encoder']) ? "Encoder=" + opts['Encoder'].refname + "\n" : ''), fmt) + buf
+				((e.encoder) ? "Encoder: #{e.encoder.refname}\n" : '') +
+				((e.nop) ? "NOP generator: #{e.nop.refname}\n" : ''), fmt) + buf
 		end
 
 		return buf

lib/msf/core.rb

@@ -24,6 +24,9 @@ require 'msf/core/framework'
 require 'msf/core/session_manager'
 require 'msf/core/session'
 
+# Wrappers
+require 'msf/core/encoded_payload'
+
 # Pseudo-modules
 require 'msf/core/handler'
 

lib/msf/core/encoded_payload.rb

@@ -18,9 +18,9 @@ class EncodedPayload
 	#
 	# Creates an encoded payload instance
 	#
-	def self.create(framework, pinst, reqs)
+	def self.create(pinst, reqs)
 		# Create the encoded payload instance
-		p = EncodedPayload.new(framework, pinst, reqs)
+		p = EncodedPayload.new(pinst.framework, pinst, reqs)
 
 		p.generate
 
@@ -37,10 +37,12 @@ class EncodedPayload
 	# Generate the full encoded payload
 	#
 	def generate
-		raw           = nil
-		encoded       = nil
-		nop_sled_size = 0
-		nop_sled      = nil
+		self.raw           = nil
+		self.encoded       = nil
+		self.nop_sled_size = 0
+		self.nop_sled      = nil
+		self.encoder       = nil
+		self.nop           = nil
 
 		# Generate the raw version of the payload first
 		generate_raw()
@@ -52,7 +54,7 @@ class EncodedPayload
 		generate_sled()
 
 		# Finally, set the complete payload definition
-		encoded = (nop_sled || '') + encoded
+		self.encoded = (self.nop_sled || '') + self.encoded
 
 		# Return the complete payload
 		return encoded
@@ -63,7 +65,7 @@ class EncodedPayload
 	# raw attribute.
 	#
 	def generate_raw
-		raw = (reqs['Prepend'] || '') + pisnt.generate + (reqs['Append'] || '')
+		self.raw = (reqs['Prepend'] || '') + pinst.generate + (reqs['Append'] || '')
 	end
 
 	#
@@ -74,32 +76,44 @@ class EncodedPayload
 		# If the exploit has bad characters, we need to run the list of encoders
 		# in ranked precedence and try to encode without them.
 		if (reqs['BadChars'])
-			pinst.compatible_encoders.each { |enc|
-				encoder = enc.new
+			encoders = pinst.compatible_encoders
+
+			# If the caller had a preferred encoder, try to find it and prefix it
+			if ((reqs['Encoder']) and
+			    (preferred = framework.encoders[reqs['Encoder']]))
+				encoders.unshift(preferred)
+			elsif (reqs['Encoder'])
+				wlog("#{pinst.refname}: Failed to find preferred encoder #{reqs['Encoder']}")
+			end
+
+			encoders.each { |encmod|
+				self.encoder = encmod.new
 			
 				# Try encoding with the current encoder
 				begin
-					p.encoded = encoder.encode(raw, reqs['BadChars'])
+					self.encoded = self.encoder.encode(self.raw, reqs['BadChars'])
 				rescue
 					wlog("#{pinst.refname}: Failed to encode payload with encoder #{encoder.refname}: #{$!}",
 						'core', LEV_1)
+					next
 				end
 
-				# Minimum number of NOPs to use
-				min = reqs['MinNops'] || 0
-
 				# Check to see if we have enough room for the minimum requirements
 				if ((reqs['Space']) and
-				    (reqs['Space'] < encoded.length + min))
+				    (reqs['Space'] < self.encoded.length + min))
 					wlog("#{pinst.refname}: Encoded payload version is too large with encoder #{encoder.refname}",
 						'core', LEV_1)
 					next
 				end
+
+				break
 			}
 			
 			# If the encoded payload is nil, raise an exception saying that we
 			# suck at life.
-			if (encoded == nil)
+			if (self.encoded == nil)
+				encoder = nil
+
 				raise NoEncodersSucceededError, 
 					"#{pinst.refname}: All encoders failed to encode.",
 					caller
@@ -107,11 +121,11 @@ class EncodedPayload
 		# If there are no bad characters, then the raw is the same as the
 		# encoded
 		else
-			encoded = raw
+			self.encoded = raw
 		end
 
 		# Prefix the prepend encoder value
-		encoded = (reqs['PrependEncoder'] || '') + encoded
+		self.encoded = (reqs['PrependEncoder'] || '') + self.encoded
 	end
 
 	#
@@ -121,48 +135,52 @@ class EncodedPayload
 		min   = reqs['MinNops'] || 0
 		space = reqs['Space']
 
-		nop_sled_size = 0
+		self.nop_sled_size = min
 
 		# Calculate the number of NOPs to pad out the buffer with based on the
 		# requirements.  If there was a space requirement, check to see if
 		# there's any room at all left for a sled.
 		if ((space) and 
 			 (space > encoded.length))
-			nop_sled_size = reqs['Space'] - encoded.length
+			self.nop_sled_size = reqs['Space'] - self.encoded.length
 		end
 
 		# If the maximum number of NOPs has been exceeded, wrap it back down.
 		if ((reqs['MaxNops']) and
 			 (reqs['MaxNops'] > sled_size))
-			nop_sled_size = reqs['MaxNops']
+			self.nop_sled_size = reqs['MaxNops']
 		end
 
 		# Now construct the actual sled
-		if (nop_sled_size > 0)
+		if (self.nop_sled_size > 0)
 			pinst.compatible_nops.each { |nopmod|
 				# Create an instance of the nop module
-				nop = nopmod.new
+				self.nop = nopmod.new
 	
 				begin
-					nop_sled = nop.generate_sled(nop_sled_size,
+					self.nop_sled = nop.generate_sled(nop_sled_size,
 						'BadChars'      => reqs['BadChars'],
 						'SaveRegisters' => reqs['SaveRegisters'])	
 				rescue
+					self.nop = nil
+
 					dlog("#{pinst.refname}: Nop generator #{nop.refname} failed to generate sled for payload: #{$!}",
 						'core', LEV_1)
 				end
+
+				break
 			}
 
-			if (nop_sled == nil)
+			if (self.nop_sled == nil)
 				raise NoNopsSucceededError, 
 					"#{pinst.refname}: All NOP generators failed to construct sled for.",
 					caller
 			end
 		else
-			nop_sled = ''
+			self.nop_sled = ''
 		end
 
-		return nop_sled
+		return self.nop_sled
 	end
 
 	#
@@ -182,6 +200,14 @@ class EncodedPayload
 	# The NOP sled itself
 	#
 	attr_reader :nop_sled
+	#
+	# The encoder that was used
+	#
+	attr_reader :encoder
+	#
+	# The NOP generator that was used
+	#
+	attr_reader :nop
 
 protected
 
@@ -190,6 +216,8 @@ protected
 	attr_writer :nop_sled_size
 	attr_writer :nop_sled
 	attr_writer :payload
+	attr_writer :encoder
+	attr_writer :nop
 
 	#
 	# The payload instance used to generate the payload

lib/msf/core/encoder.rb

@@ -116,10 +116,7 @@ class Encoder < Module
 			end
 		end
 
-		# Update the state with default decoder information
-		state.decoder_key_offset = decoder_key_offset
-		state.decoder_key_size   = decoder_key_size
-		state.decoder_key_pack   = decoder_key_pack
+		init_state(state)
 
 		# Save the buffer in the encoding state
 		state.badchars = badchars
@@ -200,6 +197,13 @@ class Encoder < Module
 
 protected
 
+	def init_state(state)
+		# Update the state with default decoder information
+		state.decoder_key_offset = decoder_key_offset
+		state.decoder_key_size   = decoder_key_size
+		state.decoder_key_pack   = decoder_key_pack
+	end
+
 	def find_key(buf, badchars)
 		key_bytes = [ ]
 		cur_key   = [ ]

lib/msf/core/encoder/xor_additive_feedback.rb

@@ -30,6 +30,8 @@ class Msf::Encoder::XorAdditiveFeedback < Msf::Encoder::Xor
 		key_bytes = integer_to_key_bytes(super(buf, badchars))
 		state = Msf::EncoderState.new
 		valid = false
+
+		init_state(state)
 	
 		# Save the original key_bytes so we can tell if we loop around
 		orig_key_bytes = key_bytes.dup

lib/msf/core/exploit.rb

@@ -179,7 +179,7 @@ class Exploit < Msf::Module
 		reqs['SaveRegisters'] = nop_save_registers
 
 		# Set the encoded payload to the result of the encoding process
-		encoded_payload = EncodedPayload.create(framework, real_payload, reqs)
+		encoded_payload = EncodedPayload.create(real_payload, reqs)
 
 		return encoded_payload
 	end

lib/msf/core/module_manager.rb

@@ -107,8 +107,8 @@ protected
 			b_name, b_mod = b
 
 			# Extract the ranking between the two modules
-			a_rank = a.const_defined?('Rank') ? a.const_get('Rank') : NormalRanking
-			b_rank = b.const_defined?('Rank') ? b.const_get('Rank') : NormalRanking
+			a_rank = a[1].const_defined?('Rank') ? a[1].const_get('Rank') : NormalRanking
+			b_rank = b[1].const_defined?('Rank') ? b[1].const_get('Rank') : NormalRanking
 
 			# Compare their relevant rankings.  Since we want highest to lowest,
 			# we compare b_rank to a_rank in terms of higher/lower precedence

lib/msf/core/payload.rb

@@ -170,8 +170,8 @@ class Payload < Msf::Module
 		encoders = []
 
 		framework.encoders.each_module_ranked(
-			'Arch' => self.arch) { |entry|
-			encoders << entry[1]
+			'Arch' => self.arch) { |name, mod|
+			encoders << mod
 		}
 
 		return encoders
@@ -184,8 +184,8 @@ class Payload < Msf::Module
 		nops = []
 
 		framework.nops.each_module_ranked(
-			'Arch' => self.arch) { |entry|
-			nops << entry[1]
+			'Arch' => self.arch) { |name, mod|
+			nops << mod
 		}
 
 		return nops

lib/msf/ui/console/command_dispatcher/payload.rb

@@ -12,6 +12,7 @@ class Payload
 		"-t" => [ true,  "The output type: ruby, perl, c, or raw."              ],
 		"-e" => [ true,  "The name of the encoder module to use."               ],
 		"-o" => [ true,  "A space separated list of options in VAR=VAL format." ],
+		"-s" => [ true,  "NOP sled length."                                     ],
 		"-h" => [ false, "Help banner."                                         ])
 
 	include Msf::Ui::Console::ModuleCommandDispatcher
@@ -29,9 +30,9 @@ class Payload
 
 		# Parse the arguments
 		encoder_name = nil
+		sled_size    = nil
 		option_str   = nil
 		badchars     = nil
-		encoder      = nil
 		type         = "ruby"
 
 		@@generate_opts.parse(args) { |opt, idx, val|
@@ -44,6 +45,8 @@ class Payload
 					encoder_name = val
 				when '-o'
 					option_str = val
+				when '-s'
+					sled_size = val.to_i
 				when '-h'
 					print(
 						"Usage: generate [options]\n\n" +
@@ -53,21 +56,15 @@ class Payload
 			end
 		}
 
-		# If an encoder name was specified, try to instantiate it 
-		if ((encoder_name) and
-		    (encoder = framework.modules.create(encoder_name)) == nil)
-			print_error("Invalid encoder specified: #{encoder_name}")
-			return false
-		end
-
 		# Generate the payload
 		begin
 			buf = Msf::Simple::Payload.generate(
 				mod, 
-				'Badchars'  => badchars,
-				'Encoder'   => encoder,
-				'Format'    => type,
-				'OptionStr' => option_str)
+				'BadChars'    => badchars,
+				'Encoder'     => encoder_name,
+				'Format'      => type,
+				'NopSledSize' => sled_size,
+				'OptionStr'   => option_str)
 		rescue
 			print_error("Payload generation failed: #{$!}")
 			return false

msfconsole

@@ -1,4 +1,7 @@
-#!/usr/bin/ruby -I../lib
+#!/usr/bin/ruby
+
+# Ghetto include for lib relative to the msfconsole script
+$:.unshift(File.join(File.dirname(__FILE__), '../lib'))
 
 require 'rex'
 require 'msf/ui'