metasploit-framework/lib/rex/encoder/ndr.rb

require "rex/text"

module Rex
module Encoder
module NDR

	# Provide padding to align the string to the 32bit boundary
	def NDR.align(string)
		return "\x00" * ((4 - (string.length & 3)) & 3)
	end

	# Encode a 4 byte long
	# use to encode:
	#       long element_1;
	def NDR.long(string)
		return [string].pack('V')
	end
	
	# Encode a 2 byte short
	# use to encode:
	#       short element_1;
	def NDR.short(string)
		return [string].pack('v')
	end
	
	# Encode a single byte
	# use to encode:
	#       byte element_1;
	def NDR.byte(string)
		return [string].pack('c')
	end

	# Encode a byte array
	# use to encode:
	#       char  element_1
	def NDR.UniConformantArray(string)
		return long(string.length) + string + align(string)
	end

	# Encode a string
	# use to encode:
	#       char *element_1;
	def NDR.string(string)
		string << "\x00" # null pad
		return long(string.length) + long(0) + long(string.length) + string + align(string)
	end
	
	# Encode a string
	# use to encode:
	#       w_char *element_1;
	def NDR.wstring(string)
		string << "\x00" # null pad
		return long(string.length) + long(0) + long(string.length) + Rex::Text.to_unicode(string) + align(Rex::Text.to_unicode(string))
	end
	
	# Encode a string and make it unique
	# use to encode:
	#       [unique] w_char *element_1;
	def NDR.uwstring(string)
		string << "\x00" # null pad
		return long(rand(0xffffffff))+long(string.length) + long(0) + long(string.length) + Rex::Text.to_unicode(string) + align(Rex::Text.to_unicode(string))
	end

	# Encode a string that is already unicode encoded
	# use to encode:
	#       w_char *element_1;
	def NDR.wstring_prebuilt(string)
		# if the string len is odd, thats bad!
		if string.length % 2 > 0
			string << "\x00"
		end
		len = string.length / 2;
		return long(len) + long(0) + long(len) + string + align(string)
	end

	# alias to wstring, going away soon
	def NDR.UnicodeConformantVaryingString(string)
		NDR.wstring(string)
	end

	# alias to wstring_prebuilt, going away soon
	def NDR.UnicodeConformantVaryingStringPreBuilt(string)
		NDR.wstring_prebuilt(string)
	end

end
end
end