Added wrapper for the Melkor mutator

Added a wrapper for the IO Active's Melkor ELF mutator. It requires the following patch:

joxeankoret/Melkor_ELF_Fuzzer@d1fb577

In order to add the 2 new mutators the following SQL commands must be executed:

 * insert into mutation_engines (name, description, command, date) values ('Melkor mutator', 'Melkor is a very intuitive and easy-to-use ELF file format fuzzer to find functional and security bugs in ELF parsers.' , '%NIGHTMARE_PATH%/mutators/melkor_mutator.py %TEMPLATES_PATH%/%FOLDER% 10 %OUTPUT%', current_date);

 * insert into mutation_engines (name, description, command, date) values ('Melkor mutator multiple', 'This is a wrapper using Melkor mutator to create a zip file with multiple fuzzed samples inside. Useful to fuzz Antivirus engines.', '%NIGHTMARE_PATH%/mutators/melkor_mutator_multiple.py %TEMPLATES_PATH%/%FOLDER% 20 %OUTPUT%', current_date);

mutators/melkor_mutator.py

@@ -0,0 +1,81 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+"""
+Nightmare Fuzzing Project
+@author: joxean
+"""
+
+import os
+import sys
+
+from shutil import rmtree
+from tempfile import mkdtemp
+
+#-----------------------------------------------------------------------
+class CMelkorMutator:
+  def __init__(self, input):
+    self.input = input
+
+  def get_diff(self, inbuf, outbuf):
+    ret = []
+    b1 = bytearray(inbuf)
+    b2 = bytearray(outbuf)
+    for i in range(len(inbuf)):
+      if b1[i] != b2[i]:
+        ret.append(str(i))
+    return ret
+
+  def read_directory(self, tmpdir):
+    base_file = os.path.basename(self.input)
+    base_dir = os.path.join(tmpdir, "orcs_%s" % base_file)
+    filename = os.path.join(base_dir, "Report_%s.txt" % base_file)
+    additional = open(filename, "rb").readlines()
+
+    filename = os.path.join(base_dir, "orc_0001")
+    return open(filename, "rb").read(), additional
+
+  def replace(self, output):
+    tmpdir = mkdtemp()
+    try:
+      old_dir = os.getcwd()
+      os.chdir(tmpdir)
+      os.system("melkor -a -q -n 1 %s" % self.input)
+      os.chdir(old_dir)
+
+      new_buf, additional = self.read_directory(tmpdir)
+      diff = self.get_diff(open(self.input, "rb").read(), new_buf)
+
+      # And, finally, write the output file
+      f = open(output, "wb")
+      f.write(new_buf)
+      f.close()
+
+      # ...and the .diff file too
+      f = open(output + ".diff", "wb")
+      f.write("# Original file created by 'Melkor Mutator' was %s\n" % self.input)
+      f.write("\n".join(diff))
+      f.write("\n")
+      for line in additional:
+        line = line.strip("\r").strip("\n")
+        f.write("# %s\n" % line)
+      f.close()
+    except:
+      print "Exception: %s" % sys.exc_info()[1]
+    finally:
+      rmtree(tmpdir)
+
+#-----------------------------------------------------------------------
+def main(input_file, output_file):
+  replacer = CMelkorMutator(input_file)
+  replacer.replace(output_file)
+
+#-----------------------------------------------------------------------
+def usage():
+  print "Usage:", sys.argv[0], "<input file> <output file>"
+
+if __name__ == "__main__":
+  if len(sys.argv) != 3:
+    usage()
+  else:
+    main(sys.argv[1], sys.argv[2])
+

mutators/melkor_mutator_multiple.py

@@ -0,0 +1,61 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+"""
+Nightmare Fuzzing Project
+This mutator creates a ZIP file with various mutated files inside.
+@author: joxean
+"""
+
+import os
+import sys
+import random
+import zipfile
+import tempfile
+
+from melkor_mutator import main as melkor_replace
+
+#-----------------------------------------------------------------------
+class CMultipleMelkorMutator:
+  def __init__(self, samples_path, total, output_zip):
+    self.samples_path = samples_path
+    self.total = total
+    self.output_zip = output_zip
+
+  def mutate(self):
+    with zipfile.ZipFile(self.output_zip, "w") as fuzz_zip:
+      fuzz_zip.comment = "NIGHTMARE"
+      for i in range(self.total):
+        name = tempfile.mktemp()
+        while 1:
+          template = random.choice(os.listdir(self.samples_path))
+          template = os.path.join(self.samples_path, template)
+          if os.path.isfile(template):
+            break
+          continue
+
+        melkor_replace(template, name)
+        try:
+          fuzz_zip.write(name)
+
+          # Add also the .diff file if it was created:
+          if os.path.exists(name + ".diff"):
+            fuzz_zip.write(name + ".diff")
+            os.remove(name + ".diff")
+          os.remove(name)
+        except:
+          print "Error:", sys.exc_info()[1]
+
+#-----------------------------------------------------------------------
+def main(path, number, output):
+  mutator = CMultipleMelkorMutator(path, int(number), output)
+  mutator.mutate()
+
+#-----------------------------------------------------------------------
+def usage():
+  print "Usage:", sys.argv[0], "samples_path #samples output_zip"
+
+if __name__ == "__main__":
+  if len(sys.argv) != 4:
+    usage()
+  else:
+    main(sys.argv[1], sys.argv[2], sys.argv[3])