Module: PEdump::SigParser

Defined in:
lib/pedump/sig_parser.rb

Defined Under Namespace

Classes: OrBlock

Constant Summary collapse

DATA_ROOT = 
File.dirname(File.dirname(File.dirname(__FILE__)))
TEXT_SIGS_FILES = 
[
  File.join(DATA_ROOT, "data", "userdb.txt"),
  File.join(DATA_ROOT, "data", "signatures.txt"),
  File.join(DATA_ROOT, "data", "fs.txt")
]

Class Method Summary collapse

Class Method Details

._add_sig(sigs, sig, args = {}) ⇒ Object

XXX “BxE9rczi GxE1bor”.force_encoding(‘binary’).to_yaml: RuntimeError: expected SCALAR, SEQUENCE-START, MAPPING-START, or ALIAS



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# File 'lib/pedump/sig_parser.rb', line 122

def _add_sig sigs, sig, args = {}
  raise "null RE: #{sig.inspect}" unless sig.re

  # bad sigs
  return if sig.re[/\A538BD833C0A30:::::/]
  return if sig.name == "Name of the Packer v1.0"
  return if sig.re == "54 68 69 73 20 70 72 6F 67 72 61 6D 20 63 61 6E 6E 6F 74 20 62 65 20 72 75 6E 20 69 6E 20 44 4F 53 20 6D 6F" # dos stub

  sig.name.sub!(/^\*\s+/,    '')
  sig.name.sub!(/\s+\(h\)$/, '')
  sig.name.sub!(/version (\d)/i,"v\\1")
  sig.name.sub!(/Microsoft/i, "MS")
  sig.name.sub!(/ or /i, " / ")
  sig.name.sub! 'RLP ','RLPack '
  sig.name.sub! '.beta', ' beta'
  sig.name.sub! '(com)','[com]'
  sig.name = sig.name.split(/\s*-+>\s*/).join(' -> ') # fix spaces around '->'

  sig.re = sig.re.strip.upcase.tr(':','?')
  sig.re = sig.re.scan(/../).join(' ') if sig.re.split.first.size > 2
  if sigs[sig.re]
    a = [sig, sigs[sig.re]].map{ |x| x.name.upcase.split('->').first.tr('V ','') }
    return if a[0][a[1]] || a[1][a[0]]

    new_name = _merge_names(sigs[sig.re].name, sig.name)
    if new_name && new_name != sig.name && new_name != sigs[sig.re].name
      puts "[.] sig name join: #{new_name}" if args[:verbose]
      sigs[sig.re].name = new_name
    end
  else
    # new sig
    sigs[sig.re] = sig
  end
end

._diff(res) ⇒ Object

range of common difference between N given sigs



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# File 'lib/pedump/sig_parser.rb', line 342

def _diff res
  raise "diff sizes" if res.map(&:size).uniq.size != 1
  size = res.first.size

  dstart  = nil
  dend    = size - 1
  prev_eq = true

  size.times do |i|
    eq = res.map{ |re| re[i] }.uniq.size == 1
    if eq != prev_eq
      if eq
        # end of current diff
        dend = i-1
      else
        # start of new diff
        return nil if dstart # return nil if it's a 2nd diff
        dstart = i
      end
    end
    prev_eq = eq
  end
  r = dstart..dend
  r == (0..(size-1)) ? nil : r
end

._join(a, sep = '') ⇒ Object 



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# File 'lib/pedump/sig_parser.rb', line 203

def _join a, sep=''
  a.map do |x|
    case x
    when OrBlock
      '(' + _join(x, '|') + ')'
    when Array
      _join x
    when String
      x
    end
  end.join(sep)
end

._merge(sigs) ⇒ Object

merge array of signatures into one signature



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# File 'lib/pedump/sig_parser.rb', line 369

def _merge sigs
  sizes = sigs.map(&:re).map(&:size)

  if sizes.uniq.size != 1
    puts "[?] wrong sizes: #{sizes.inspect}"
    return nil
  end

  res = sigs.map(&:re)
  diff = _diff res
  return nil unless diff

  ref = res.first
  ref[0...diff.first] + [OrBlock.new(res.map{ |re| re[diff] })] + ref[(diff.last+1)..-1]
end

._merge_names(name1, name2) ⇒ Object 



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# File 'lib/pedump/sig_parser.rb', line 157

def _merge_names name1, name2
  a = [name1, name2].map{ |x| x.split('->').first.split }

  d = [a[0]-a[1], a[1]-a[0]] # different words
  d.map! do |x|
    x - [
      'EXE','[EXE]',
      'vx.x','v?.?',
      'DLL','(DLL)','[DLL]',
      '[LZMA]','(LZMA)','LZMA',
      '-','~','(pack)','(1)','(2)',
      '19??'
    ]
  end
  return if d.all?(&:empty?) # no different words

  # [["v1.14/v1.20"], ["v1.14,", "v1.20"]]]
  # [["EXEShield", "v0.3b/v0.3", "v0.6"], ["Shield", "v0.3b,", "v0.3"]]]
  2.times do |i|
    return if d[i].all? do |x|
      x = x.downcase.delete(',-').sub(/tm$/,'')
      d[1-i].any? do |y|
        y = y.downcase.delete(',-').sub(/tm$/,'')
        y[x]
      end
    end
  end

  a = name1.split
  b = name2.split
  new_name_head = []
  while a.any? && b.any? && a.first.upcase == b.first.upcase
    new_name_head << a.shift
    b.shift
  end
  new_name_tail = []
  while a.any? && b.any? && a.last.upcase == b.last.upcase
    new_name_tail.unshift a.pop
    b.pop
  end
  new_name = new_name_head
  new_name << [a.join(' '), b.join(' ')].delete_if{|x| x.empty?}.join(' / ')
  new_name += new_name_tail
  new_name = new_name.join(' ')
end

._optimize(sigs) ⇒ Object 



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# File 'lib/pedump/sig_parser.rb', line 227

def _optimize sigs
  nfound   = 0
  min_sz   = 6
  max_diff = 6
  sigs.each_with_index do |sig1,idx|
    #break if idx == 100
    next if sig1.re.size < min_sz
    next if sig1.name['PseudoSigner']

    sigs[(idx+1)..-1].each do |sig2|
      next if sig2.re.size < min_sz
      next if sig2.name['PseudoSigner']

      if rd = _re_diff(sig1.re, sig2.re, max_diff)
        if    rd.all?{ |x| x[0].nil? || x[0] == '.' } && sig2.re.size >= sig1.re.size
          if new_name = _merge_names(sig2.name, sig1.name)
            #pp ["FIRST", sig1.name, sig2.name, new_name, sig1.re.join, sig2.re.join] if new_name
            sig1.name = new_name
          end
          sig2.ep_only ||= sig1.ep_only
          sig2.re = []
        elsif rd.all?{ |x| x[1].nil? || x[1] == '.' } && sig1.re.size >= sig2.re.size
          if new_name = _merge_names(sig2.name, sig1.name)
            #pp ["SECOND", sig1.name, sig2.name, new_name, sig1.re.join, sig2.re.join] if new_name
            sig2.name = new_name
          end
          sig1.re = []
          sig1.ep_only ||= sig2.ep_only
          break
        else
          next
        end
        nfound += 1
      end
    end
  end

  sigs.delete_if{ |sig| sig.re.empty? }
end

._re_diff(a, b, max_cnt = 1000) ⇒ Object 



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# File 'lib/pedump/sig_parser.rb', line 216

def _re_diff a,b, max_cnt = 1000
  r = []
  [a,b].map(&:size).max.times.map do |i|
    if a[i] != b[i]
      r << [a[i],b[i]]
      return nil if r.size > max_cnt
    end
  end
  r
end

.optimize(sigs) ⇒ Object 



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# File 'lib/pedump/sig_parser.rb', line 267

def optimize sigs
  # replaces all duplicate names with references to one name
  # saves ~30k out of ~200k mem
  h = {}
  sigs.each do |sig|
    sig.name = (h[sig.name] ||= sig.name)
  end

  print "[.] sigs merge: #{sigs.size}"; _optimize(sigs); puts  " -> #{sigs.size}"

  # try to merge signatures with same name, size & ep_only
  sigs.group_by{ |sig|
    [sig.re.size, sig.name, sig.ep_only]
  }.values.each do |a|
    next if a.size == 1
    if merged_re = _merge(a)
      a.first.re = merged_re
      a[1..-1].each{ |sig| sig.re = nil }
    end
  end
  print "[.] sigs merge: #{sigs.size}"; sigs.delete_if{ |x| x.re.nil? }; puts  " -> #{sigs.size}"


  # 361 entries of ["VMProtect v1.25 (PolyTech)", true, "h....\xE8...."])
  sigs.group_by{ |sig|
    [sig.name, sig.ep_only, sig.re[0,10].join]
  }.each do |k,entries|
    next if entries.size < 10
    #printf "%5d  %s\n", entries.size, k
    prefix = entries.first.re[0,10]
    infix  = entries.map{ |sig| sig.re[10..-1] }

    entries.first.re   = prefix + [OrBlock.new(infix)]
    entries.first.size = entries.map(&:size).max

    entries[1..-1].each{ |sig| sig.re = nil }
  end
  print "[.] sigs merge: #{sigs.size}"; sigs.delete_if{ |x| x.re.nil? }; puts  " -> #{sigs.size}"


#        # merge signatures with same prefix & suffix
#        # most ineffecient part :)
#        sigs.group_by{ |sig|
#          [sig.name, sig.ep_only, sig.re.index{ |x| x.is_a?(Array)}]
#        }.values.each do |a|
#          next if a.size == 1
#          next unless idx = a.first.re.index{ |x| x.is_a?(Array) }
#          a.group_by{ |sig| [sig.re[0...idx], sig.re[(idx+1)..-1]] }.each do |k,entries|
#            # prefix |            infix          | suffix
#            # s o m    [[b r e r o] [e w h a t]]   h e r e
#            prefix, suffix = k
#            infix = entries.map{ |sig| sig.re[idx] }
#            #infix = [['f','o','o']]
#            merged_re = prefix + infix + suffix
#            max_size = entries.map(&:size).max
#            entries.each{ |sig| sig.re = merged_re; sig.size = max_size }
#          end
#        end
#        print "[.] sigs merge: #{sigs.size}"; sigs.uniq!; puts  " -> #{sigs.size}"

   # stats
#        aa = []
#        6.upto(20) do |len|
#          sigs.group_by{ |sig| [sig.re[0,len].join, sig.name, sig.ep_only] }.each do |a,b|
#            aa << [b.size, a[0], [b.map(&:size).min, b.map(&:size).max].join(' .. ') ] if b.size > 2
#          end
#        end
#        aa.sort_by(&:first).each do |sz,prefix,name|
#          printf "%5d  %-50s %s\n", sz, prefix.inspect, name
#        end

  sigs
end

.parse(args = {}) ⇒ Object

parse text signatures



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# File 'lib/pedump/sig_parser.rb', line 17

def parse args = {}
  args[:fnames] ||= TEXT_SIGS_FILES
  sigs = {}; sig = nil

  args[:fnames].each do |fname|
    n0 = sigs.size
    File.open(fname,'r:utf-8') do |f|
      while line = f.gets
        case line.strip
        when /^[<;#]/, /^$/ # comments & blank lines
          next
        when /^\[(.+)=(.+)\]$/
          _add_sig(sigs, Packer.new($1, $2, true), args )
        when /^\[([^=]+)\]$/
          sig = Packer.new($1)
        when /^signature = (.+)$/
          sig.re = $1
          _add_sig(sigs, sig, args)
        when /^ep_only = (.+)$/
          sig.ep_only = ($1.strip.downcase == 'true')
        else raise line
        end
      end
    end
    puts "[=] #{sigs.size-n0} sigs from #{File.basename(fname)}\n\n" if args[:verbose]
  end

  bins = Hash.new{ |k,v| k[v] = ''.force_encoding('binary') }

  # convert strings to Regexps
  sigs = sigs.values
  sigs.each_with_index do |sig,idx|
    sig.re =
      sig.re.split(' ').tap do |a|
        sig.size = a.size
      end.map do |x|
        case x
        when /\A\?\?\Z/
          bins[sig] << '.'
          '.'
        when /\A.\?/,/\?.\Z/
          puts "[?] #{x.inspect} -> \"??\" in #{sig.name}" if args[:verbose]
          bins[sig] << '.'
          '.'
        when /\A[a-f0-9]{2}\Z/i
          x = x.to_i(16).chr
          bins[sig] << x
          args[:raw] ? x : Regexp::escape(x)
        else
          puts "[?] unknown re element: #{x.inspect} in #{sig.inspect}" if args[:verbose]
          "BAD_RE"
          break
        end
      end
    if sig.name[/-+>/]
      a = sig.name.split(/-+>/,2).map(&:strip)
      sig.name = "#{a[0]} (#{a[1]})"
    end
    sig.re.pop while sig.re.last == '??'
  end
  sigs.delete_if{ |sig| !sig.re || sig.re.index('BAD_RE') }
  return sigs if args[:raw]

#        require 'awesome_print'
#        bins.each do |bin_sig, bin|
#          next if bin.size < 5
#          #next unless bin_sig.name['UPX']
#
#          bin_re = Regexp.new(bin_sig.re.join, Regexp::MULTILINE)
#          was = false
#          sigs.each do |sig|
#            next if sig.size < 5 || sig == bin_sig
#            #next unless sig.name['UPX']
#
#            re = Regexp.new(sig.re.join, Regexp::MULTILINE)
#            if bin.index(re) == 0
#              rd = _re_diff(bin_re.source, re.source)
#              if rd.any? && rd.size <= 4
#                #if sig.name.split.first.upcase != bin_sig.name.split.first.upcase
#                  puts "\n[.] #{bin_sig.name.yellow}\n#{bin_re.source.inspect.red}" unless was
#                  puts "[=] #{sig.name}"
#                  puts re.source.inspect.green
#                  p rd
#                  was = true
#                #end
#              end
#            end
#          end
#        end


  optimize sigs if args[:optimize]

  # convert re-arrays to Regexps
  sigs.each do |sig|
    sig.re = Regexp.new( _join(sig.re), Regexp::MULTILINE )
  end

  sigs
end