100 lines
1.8 KiB
Ruby
100 lines
1.8 KiB
Ruby
##
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# $Id$
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# Version: $Revision$
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##
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##
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# Rex::OLE - an OLE implementation
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# written in 2010 by Joshua J. Drake <jduck [at] metasploit.com>
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##
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module Rex
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module OLE
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class FAT < DIFAT
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#
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# low-level functions
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#
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def read(difat)
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@entries = []
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cnt = left = @stg.header._csectFat
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difat.each { |fs|
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break if (left == 0)
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if (fs != SECT_FREE)
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buf = @stg.read_sector(fs, @stg.header.sector_size)
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arr = Util.get32array(buf)
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# hax!
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if (@entries[fs] == SECT_DIF)
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# chop the next ptr
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@entries += arr.slice!(0, arr.length - 1)
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else
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@entries += arr
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end
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left -= 1
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end
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}
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if (left != 0)
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raise RuntimeError, 'Only found %u of %u sectors' % [(cnt - left), cnt]
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end
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end
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def allocate_sector(type=nil)
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idx = @entries.index(SECT_FREE)
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if (not idx)
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# add a sector worth
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idx = @entries.length
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@stg.header.idx_per_sect.times {
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@entries << SECT_FREE
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}
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end
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# mark the sector as in use
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if (type)
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@entries[idx] = type
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else
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# default normal sectors to end of chain
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@entries[idx] = SECT_END
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end
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idx
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end
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def write(difat)
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# we build the difat as we write these..
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difat.reset
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# allocate the sectors
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fat_sects = []
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left = @entries.length
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while (left > 0)
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if (left > @stg.header.idx_per_sect)
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left -= @stg.header.idx_per_sect
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else
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left = 0
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end
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fat_sects << allocate_sector(SECT_FAT)
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end
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# write the fat into the difat/allocated sectors
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copy = @entries.dup
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fat_sects.each { |fs|
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part = copy.slice!(0, @stg.header.idx_per_sect)
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sbuf = Util.pack32array(part)
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if (sbuf.length != @stg.header.sector_size)
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raise RuntimeError, 'Unsupported number of fat sectors (not multiple of idx per sect)'
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end
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@stg.write_sector_raw(fs, sbuf)
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difat << fs
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}
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end
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end
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end
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end
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