Class: Rex::OLE::DIFAT

Inherits:
Object
  • Object
show all
Defined in:
lib/rex/ole/difat.rb

Direct Known Subclasses

FAT, MiniFAT

Instance Method Summary collapse

Constructor Details

#initialize(stg) ⇒ DIFAT

Returns a new instance of DIFAT.



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# File 'lib/rex/ole/difat.rb', line 16

def initialize stg
	@stg = stg
	@entries = []
end

Instance Method Details

#+(expr) ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 32

def +(expr)
	@entries += expr
	self
end

#<<(expr) ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 37

def <<(expr)
	@entries << expr
end

#[](idx) ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 28

def [](idx)
	@entries[idx]
end

#[]=(idx, expr) ⇒ Object

convenience access to entries



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# File 'lib/rex/ole/difat.rb', line 24

def []=(idx,expr)
	@entries[idx] = expr
end

#each ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 53

def each
	@entries.each { |el|
		yield el
	}
end

#length ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 41

def length
	@entries.length
end

#read ⇒ Object

low-level functions



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# File 'lib/rex/ole/difat.rb', line 86

def read
	@entries = []

	# start with the header part
	@entries += @stg.header._sectFat

	# double indirect fat
	sect = @stg.header._sectDifStart
	while (sect != SECT_END)
		if (@entries.include?(sect))
			raise RuntimeError, 'Sector chain loop detected (0x%08x)' % sect
		end

		@entries << sect
		buf = @stg.read_sector(sect, @stg.header.sector_size)

		# the last sect ptr in the block becomes the next entry
		sect = Util.get32(buf, ((@stg.header.idx_per_sect)-1) * 4)
	end

	# don't need these free ones, but it doesn't hurt to keep them.
	#@difat.delete(SECT_FREE)
end

#reset ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 49

def reset
	@entries = []
end

#slice!(start, stop) ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 45

def slice!(start,stop)
	@entries.slice!(start,stop)
end

#to_s ⇒ Object

woop



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# File 'lib/rex/ole/difat.rb', line 62

def to_s
	ret = "{ "
	@entries.each { |el|
		ret << ", " if (ret.length > 2)
		case el
		when SECT_END
			ret << "END"
		when SECT_DIF
			ret << "DIF"
		when SECT_FAT
			ret << "FAT"
		when SECT_FREE
			ret << "FREE"
		else
			ret << "0x%x" % el
		end
	}
	ret << " }"
	ret
end

#write ⇒ Object 



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# File 'lib/rex/ole/difat.rb', line 110

def write
	len = @entries.length
	first109 = @entries.dup

	rest = nil
	if (len > 109)
		rest = first109.slice!(109,len)
	end

	@stg.header._sectFat = []
	@stg.header._sectFat += first109
	if (len < 109)
		need = 109 - len
		need.times {
			@stg.header._sectFat << SECT_FREE
		}
	end

	if (rest and rest.length > 0)
		raise RuntimeError, 'TODO: support writing DIF properly!'
		# may require adding more fat sectors :-/
		#@stg.header._csectDif = rest.length
		#@stg.header._sectDifStart = idx
	end

	@stg.header._csectFat = len
end