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", "jc-userdb.txt"),
  File.join(DATA_ROOT, "data", "fs.txt"),         # has special parse options!
]
SPECIAL_PARSE_OPTIONS = 
{
  File.join(DATA_ROOT, "data", "fs.txt") => {:fix1 => true}
}

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



134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
 
# File 'lib/pedump/sig_parser.rb', line 134

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.name == "Alias PIX/Vivid IMG Graphics format"
  return if sig.name == "JAR Archive"
  return if sig.name == "Turbo / Borland Pascal v7.x Unit"
  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.gsub!(/ V(\d)/, " v\\1") # V1.1 -> v1.1
  sig.name = sig.name.split(/\s*-+>\s*/).join(' -> ') # fix spaces around '->'
  sig.name = sig.name.split(' ').delete_if do |x|
    # delete words: vX.X, v?.?, ?.?, x.x
    x =~ /\Av?[?x]\.[?x]\Z/i
  end.join(' ')

  sig.re = sig.re.strip.upcase.tr(':','?')
  sig.re = sig.re.scan(/../).join(' ') if sig.re.split.first.size > 2

  # sig contains entirely zeroes or masks or only both
  a_bad = [%w'00', %w'??', %w'00 ??', %w'90', %w'90 ??']
  # ?a, 0? => ??, ??
  a_cur = sig.re.split.map{ |x| x['?'] ? '??' : x }.uniq.sort
  return if a_bad.include?(a_cur)

  # first byte is unique and all others are zeroes or masks
  a_cur = sig.re.split[1..-1].map{ |x| x['?'] ? '??' : x }.uniq.sort
  return if a_bad.include?(a_cur)

  # too short signatures
  if sig.re.split.delete_if{ |x| x['?'] }.size < 3
    require 'awesome_print'
    puts sig.inspect.red
  end

  # fs.txt contains a lot of signatures that copied from other sources
  # BUT have all 01 replaced with '??'
  # // replaced the file with filtered one (see 'fs-good' below) // zzz
  if args[:fix1]
    sigs.keys.each do |re|
      if re.gsub("01","??") == sig.re
        puts "[.] fix1: rejecting #{sig.name} - already present with 01 in place" if args[:verbose]
        return
      end
    end
#          File.open("fs-good.txt","a") do |f|
#            f << "[#{sig.name}=#{sig.re.tr(' ','')}]\n"
#          end
  end

  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



462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
 
# File 'lib/pedump/sig_parser.rb', line 462

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
  dstart ||= 0
  r = dstart..dend
  r == (0..(size-1)) ? nil : r
end

._join(a, sep = '') ⇒ Object 



294
295
296
297
298
299
300
301
302
303
304
305
 
# File 'lib/pedump/sig_parser.rb', line 294

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



490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
 
# File 'lib/pedump/sig_parser.rb', line 490

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 



209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
 
# File 'lib/pedump/sig_parser.rb', line 209

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]',
      'DLL','(DLL)','[DLL]',
      '[LZMA]','(LZMA)','LZMA',
      '-','~','(pack)','(1)','(2)',
      '19??',
      'with:', 'with?'
    ]
  end
  return if d.all?(&:empty?) # no different words => can keep ANY name


#        if name1 =~ /pecompact/i
#          require 'awesome_print'
#          puts "[d] #{name1}".yellow
#          puts "[d] #{name2}".yellow
#        end

  # [["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

#        require 'awesome_print'
#        puts "[d] #{name1.yellow} #{name2.green}"

  a = name1.split
  b = name2.split

  # merge common head
  new_name_head = []
  while a.any? && b.any? && a.first.upcase == b.first.upcase
    new_name_head << a.shift
    b.shift
  end

  # merge common tail
  new_name_tail = []
  while a.any? && b.any? && a.last.upcase == b.last.upcase
    new_name_tail.unshift a.pop
    b.pop
  end

  # rm common words from middle
  separators = [ "/", "->" ]
  was = true
  while was
    was = false
    b.each do |bw|
      next if bw == "/" || bw == "->"
      if a.include?(bw) || a.include?(bw+")") || a.include?("("+bw) || a.include?("(#{bw})")
        b -= [bw]
        was = true
        break
      end
    end
  end
  while separators.include?(b.last)
    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
#        if name1 =~ /pecompact/i
#          p a
#          p b
#          p new_name_tail
#        puts "[=] #{new_name.inspect}".red
#        end
  new_name = new_name.join(' ')
end

._name2wordonly(name) ⇒ Object 



360
361
362
 
# File 'lib/pedump/sig_parser.rb', line 360

def _name2wordonly name
  name.downcase.split(/[^a-z0-9_.]+/).join(' ').strip
end

._optimize(sigs) ⇒ Object 



318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
 
# File 'lib/pedump/sig_parser.rb', line 318

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)
#                  require 'pp'
#                  pp ["FIRST", sig1.name, sig2.name, new_name, sig1.re.join, sig2.re.join] if new_name =~ /pecompact/i
            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)
#                  require 'pp'
#                  pp ["SECOND", sig1.name, sig2.name, new_name, sig1.re.join, sig2.re.join] if new_name =~ /pecompact/i
            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 



307
308
309
310
311
312
313
314
315
316
 
# File 'lib/pedump/sig_parser.rb', line 307

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 



392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
 
# File 'lib/pedump/sig_parser.rb', line 392

def optimize sigs
  optimize_names sigs

  # XXX no optimize from now, prefer more precise sigs
  #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

.optimize_names(sigs) ⇒ Object 



364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
 
# File 'lib/pedump/sig_parser.rb', line 364

def optimize_names sigs
  # replaces all duplicate names with references to one name
  # saves ~30k out of ~200k mem
  h = {}

  # find shortest names
  sigs.each do |sig|
    t = _name2wordonly(sig.name)
    if h[t]
      # keep shortest name
      if h[t] != sig.name
        #print "[d] #{[h[t], sig.name].inspect} -> "
        h[t] = [h[t], sig.name].sort_by(&:size).first
        #puts h[t]
      else
        # fully identical names
      end
    else
      h[t] = sig.name
    end
  end

  # assign names back to sigs
  sigs.each{ |sig| sig.name = h[_name2wordonly(sig.name)] }

  puts "[.] sigs merge: #{h.size} unique names"
end

.parse(args = {}) ⇒ Object

parse text signatures



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
 
# File 'lib/pedump/sig_parser.rb', line 22

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

  args[:fnames].each do |fname|
    n0 = sigs.size; add_sig_args = args.dup
    add_sig_args.merge!(SPECIAL_PARSE_OPTIONS[fname] || {})
    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), add_sig_args )
        when /^\[([^=]+)\](\s+\/\/.+)?$/
          sig = Packer.new($1)
        when /^signature = (.+)$/
          sig.re = $1
          _add_sig(sigs, sig, add_sig_args)
        when /^ep_only = (.+)$/
          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
          if args[:raw]
            x
          elsif args[:raword]
            x.ord
          else
            Regexp::escape(x)
          end
        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 && sig.re.last == '??'
  end
  sigs.delete_if{ |sig| !sig.re || sig.re.index('BAD_RE') }
  return sigs if args[:raw] || args[:raword]

#        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