metasploit-framework/lib/rex/ole/difat.rb

143 lines
2.1 KiB
Ruby

# -*- coding: binary -*-
##
# $Id$
# Version: $Revision$
##
##
# Rex::OLE - an OLE implementation
# written in 2010 by Joshua J. Drake <jduck [at] metasploit.com>
##
module Rex
module OLE
class DIFAT
def initialize stg
@stg = stg
@entries = []
end
#
# convenience access to entries
#
def []=(idx,expr)
@entries[idx] = expr
end
def [](idx)
@entries[idx]
end
def +(expr)
@entries += expr
self
end
def <<(expr)
@entries << expr
end
def length
@entries.length
end
def slice!(start,stop)
@entries.slice!(start,stop)
end
def reset
@entries = []
end
def each
@entries.each { |el|
yield el
}
end
#
# woop
#
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
#
# low-level functions
#
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
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
end
end
end