139 lines
2.3 KiB
Ruby
139 lines
2.3 KiB
Ruby
# -*- coding: binary -*-
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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 DIFAT
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def initialize stg
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@stg = stg
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@entries = []
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end
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#
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# convenience access to entries
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#
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def []=(idx,expr)
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@entries[idx] = expr
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end
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def [](idx)
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@entries[idx]
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end
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def +(expr)
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@entries += expr
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self
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end
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def <<(expr)
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@entries << expr
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end
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def length
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@entries.length
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end
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def slice!(start,stop)
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@entries.slice!(start,stop)
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end
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def reset
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@entries = []
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end
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def each
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@entries.each { |el|
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yield el
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}
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end
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#
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# woop
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#
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def to_s
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ret = "{ "
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@entries.each { |el|
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ret << ", " if (ret.length > 2)
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case el
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when SECT_END
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ret << "END"
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when SECT_DIF
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ret << "DIF"
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when SECT_FAT
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ret << "FAT"
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when SECT_FREE
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ret << "FREE"
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else
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ret << "0x%x" % el
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end
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}
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ret << " }"
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ret
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end
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#
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# low-level functions
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#
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def read
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@entries = []
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# start with the header part
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@entries += @stg.header._sectFat
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# double indirect fat
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sect = @stg.header._sectDifStart
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while (sect != SECT_END)
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if (@entries.include?(sect))
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raise RuntimeError, 'Sector chain loop detected (0x%08x)' % sect
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end
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@entries << sect
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buf = @stg.read_sector(sect, @stg.header.sector_size)
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# the last sect ptr in the block becomes the next entry
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sect = Util.get32(buf, ((@stg.header.idx_per_sect)-1) * 4)
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end
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# don't need these free ones, but it doesn't hurt to keep them.
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#@difat.delete(SECT_FREE)
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end
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def write
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len = @entries.length
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first109 = @entries.dup
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rest = nil
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if (len > 109)
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rest = first109.slice!(109,len)
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end
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@stg.header._sectFat = []
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@stg.header._sectFat += first109
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if (len < 109)
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need = 109 - len
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need.times {
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@stg.header._sectFat << SECT_FREE
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}
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end
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if (rest and rest.length > 0)
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raise RuntimeError, 'TODO: support writing DIF properly!'
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# may require adding more fat sectors :-/
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#@stg.header._csectDif = rest.length
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#@stg.header._sectDifStart = idx
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end
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@stg.header._csectFat = len
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end
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end
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end
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end
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