Class: Rex::Post::Meterpreter::Tlv

Inherits:
Object
  • Object
show all
Defined in:
lib/rex/post/meterpreter/packet.rb

Overview

Base TLV (Type-Length-Value) class

Direct Known Subclasses

GroupTlv

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type, value = nil, compress = false) ⇒ Tlv

Returns an instance of a TLV.



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# File 'lib/rex/post/meterpreter/packet.rb', line 113

def initialize(type, value = nil, compress=false)
	@type     = type
	@compress = compress
	
	if (value != nil)
		if (type & TLV_META_TYPE_STRING == TLV_META_TYPE_STRING)
			if (value.kind_of?(Fixnum))
				@value = value.to_s
			else
				@value = value.dup
			end
		else
			@value = value
		end
	end
end

Instance Attribute Details

#compress ⇒ Object

Returns the value of attribute compress.



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# File 'lib/rex/post/meterpreter/packet.rb', line 102

def compress
  @compress
end

#type ⇒ Object

Returns the value of attribute type.



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# File 'lib/rex/post/meterpreter/packet.rb', line 102

def type
  @type
end

#value ⇒ Object

Returns the value of attribute value.



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# File 'lib/rex/post/meterpreter/packet.rb', line 102

def value
  @value
end

Instance Method Details

#from_r(raw) ⇒ Object

Translates the raw format of the TLV into a sanitize version.



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# File 'lib/rex/post/meterpreter/packet.rb', line 266

def from_r(raw)
	self.value  = nil

	length, self.type = raw.unpack("NN");

	# check if the tlv value has been compressed...
	if( self.type & TLV_META_TYPE_COMPRESSED == TLV_META_TYPE_COMPRESSED )
		# set this TLV as using compression
		@compress = true
		# remove the TLV_META_TYPE_COMPRESSED flag from the tlv type to restore the 
		# tlv type to its origional, allowing for transparent data compression.
		self.type = self.type ^ TLV_META_TYPE_COMPRESSED
		# decompress the compressed data (skipping the length and type DWORD's)
		raw_decompressed = Rex::Text.zlib_inflate( raw[8..length-1] )
		# update the length to reflect the decompressed data length (+8 for the length and type DWORD's)
		length = raw_decompressed.length + 8
		# update the raw buffer with the new length, decompressed data and updated type.
		raw = [length, self.type].pack("NN") + raw_decompressed
	end
	
	if (self.type & TLV_META_TYPE_STRING == TLV_META_TYPE_STRING)
		if (raw.length > 0)
			self.value = raw[8..length-2]
		else
			self.value = nil
		end
	elsif (self.type & TLV_META_TYPE_UINT == TLV_META_TYPE_UINT)
		self.value = raw.unpack("NNN")[2]
	elsif (self.type & TLV_META_TYPE_QWORD == TLV_META_TYPE_QWORD)
		self.value = raw.unpack("NNQ")[2] 		
		self.value = self.ntohq( self.value )
	elsif (self.type & TLV_META_TYPE_BOOL == TLV_META_TYPE_BOOL)
		self.value = raw.unpack("NNc")[2]

		if (self.value == 1)
			self.value = true
		else
			self.value = false
		end
	else
		self.value = raw[8..length-1]
	end

	return length;
end

#inspect ⇒ Object 



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# File 'lib/rex/post/meterpreter/packet.rb', line 130

def inspect
	utype = type ^ TLV_META_TYPE_COMPRESSED
	meta = case (utype & TLV_META_MASK)
		when TLV_META_TYPE_STRING; "STRING"
		when TLV_META_TYPE_UINT; "INT"
		when TLV_META_TYPE_RAW; "RAW"
		when TLV_META_TYPE_BOOL; "BOOL"
		when TLV_META_TYPE_QWORD; "QWORD"
		when TLV_META_TYPE_GROUP; "GROUP"
		when TLV_META_TYPE_COMPLEX; "COMPLEX"
		else; 'unknown-meta-type'
		end
	stype = case type
		when PACKET_TYPE_REQUEST; "Request"
		when PACKET_TYPE_RESPONSE; "Response"
		when TLV_TYPE_REQUEST_ID; "REQUEST-ID"
		when TLV_TYPE_METHOD; "METHOD"
		when TLV_TYPE_RESULT; "RESULT"
		when TLV_TYPE_EXCEPTION; "EXCEPTION"
		when TLV_TYPE_STRING; "STRING"
		when TLV_TYPE_UINT; "UINT"
		when TLV_TYPE_BOOL; "BOOL"

		when TLV_TYPE_LENGTH; "LENGTH"
		when TLV_TYPE_DATA; "DATA"
		when TLV_TYPE_FLAGS; "FLAGS"

		when TLV_TYPE_CHANNEL_ID; "CHANNEL-ID"
		when TLV_TYPE_CHANNEL_TYPE; "CHANNEL-TYPE"
		when TLV_TYPE_CHANNEL_DATA; "CHANNEL-DATA"
		when TLV_TYPE_CHANNEL_DATA_GROUP; "CHANNEL-DATA-GROUP"
		when TLV_TYPE_CHANNEL_CLASS; "CHANNEL-CLASS"
		when TLV_TYPE_CHANNEL_PARENTID; "CHANNEL-PARENTID"

		when TLV_TYPE_SEEK_WHENCE; "SEEK-WHENCE"
		when TLV_TYPE_SEEK_OFFSET; "SEEK-OFFSET"
		when TLV_TYPE_SEEK_POS; "SEEK-POS"

		when TLV_TYPE_EXCEPTION_CODE; "EXCEPTION-CODE"
		when TLV_TYPE_EXCEPTION_STRING; "EXCEPTION-STRING"

		when TLV_TYPE_LIBRARY_PATH; "LIBRARY-PATH"
		when TLV_TYPE_TARGET_PATH; "TARGET-PATH"
		when TLV_TYPE_MIGRATE_PID; "MIGRATE-PID"
		when TLV_TYPE_MIGRATE_LEN; "MIGRATE-LEN"
		when TLV_TYPE_MIGRATE_PAYLOAD; "MIGRATE-PAYLOAD"
		when TLV_TYPE_MIGRATE_ARCH; "MIGRATE-ARCH"

		# Extension classes don't exist yet, so can't use their constants
		# here.
		#when Extensions::Stdapi::TLV_TYPE_IP;           'ip-address'
		else; "unknown-#{type}"
		end
	val = value.inspect
	if val.length > 50
		val = val[0,50] + ' ..."'
	end
	"#<#{self.class} type=#{stype} #{self.class.to_s =~ /Packet/ ? "tlvs=#{@tlvs.inspect}" : "meta=#{meta} value=#{val}"} >"
end

#meta_type?(meta) ⇒ Boolean

Checks to see if a TLVs meta type is equivalent to the meta type passed.

Returns:

  • (Boolean) 


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# File 'lib/rex/post/meterpreter/packet.rb', line 199

def meta_type?(meta)
	return (self.type & meta == meta)
end

#to_r ⇒ Object

Converts the TLV to raw.



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# File 'lib/rex/post/meterpreter/packet.rb', line 226

def to_r
	raw = value.to_s;

	if (self.type & TLV_META_TYPE_STRING == TLV_META_TYPE_STRING)
		raw += "\x00"
	elsif (self.type & TLV_META_TYPE_UINT == TLV_META_TYPE_UINT)
		raw = [value].pack("N")
	elsif (self.type & TLV_META_TYPE_QWORD == TLV_META_TYPE_QWORD)
		raw = [ self.htonq( value.to_i ) ].pack("Q")
	elsif (self.type & TLV_META_TYPE_BOOL == TLV_META_TYPE_BOOL)
		if (value == true)
			raw = [1].pack("c")
		else
			raw = [0].pack("c")
		end
	end
	
	# check if the tlv is to be compressed...
	if( @compress )
		raw_uncompressed = raw
		# compress the raw data
		raw_compressed = Rex::Text.zlib_deflate( raw_uncompressed )
		# check we have actually made the raw data smaller...
		# (small blobs often compress slightly larger then the origional) 
		# if the compressed data is not smaller, we dont use the compressed data
		if( raw_compressed.length < raw_uncompressed.length )
			# if so, set the TLV's type to indicate compression is used
			self.type = self.type | TLV_META_TYPE_COMPRESSED
			# update the raw data with the uncompressed data length + compressed data
			# (we include the uncompressed data length as the C side will need to know this for decompression)
			raw = [ raw_uncompressed.length ].pack("N") + raw_compressed
		end
	end
	
	return [raw.length + 8, self.type].pack("NN") + raw
end

#type?(type) ⇒ Boolean

Checks to see if the TLVs type is equivalent to the type passed.

Returns:

  • (Boolean) 


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# File 'lib/rex/post/meterpreter/packet.rb', line 206

def type?(type)
	return self.type == type
end

#value?(value) ⇒ Boolean

Checks to see if the TLVs value is equivalent to the value passed.

Returns:

  • (Boolean) 


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# File 'lib/rex/post/meterpreter/packet.rb', line 213

def value?(value)
	return self.value == value
end