check for nop before growth

sins/mutation.py

@@ -4,6 +4,8 @@ from random import randint
 import ctypes
 import mmap
 
+from .disassemble import disasm
+
 seed_shell = b''.join([
     b'\x55',
     b'\x48\x89\xe5',
@@ -53,14 +55,14 @@ def generation(queue: Queue, shellcode: bytes):
 
 
 def growth(*, shellcode: bytes, length: int) -> bytes:
+    for mnemonic, op_str in disasm(shellcode):
+        if mnemonic == 'nop':
+            return bytes(shellcode)
+
+    if length <= len(shellcode):
+        return bytes(shellcode)
+
     shellcode = bytearray(shellcode)
-
+    shellcode += b'\x90'
-    # slow growth and stop shrinking
-    if length > len(shellcode):
-        growth = 1
-    else:
-        growth = 0
-
-    shellcode = shellcode + (b'\x90' * growth)
 
     return bytes(shellcode)

sins/orm.py

@@ -43,7 +43,7 @@ class ScrapNode(Base):
         self.image = child
         self.length = len(child)
         self.sha1sum
-        self.disasm = disasm(child)
+        self.disasm = str(disasm(child))
 
     def __repr__(self):
         values = {
@@ -66,12 +66,3 @@ class ScrapNode(Base):
         self.checksum = checksum.hexdigest()
 
         return self.checksum
-
-
-def disasm(shellcode: bytes) -> str:
-    opcodes = list()
-
-    for opcode in capstone.disasm(shellcode, 0):
-        opcodes += f'{opcode.mnemonic}    {opcode.op_str}\n'
-
-    return opcodes

sins/run.py

@@ -65,24 +65,21 @@ def sins():
             seed_data = seed_file.read()
 
         seed = ScrapNode(child=seed_data)
-
-        exists = session.query(ScrapNode).filter(
-            ScrapNode.checksum == seed.checksum)
-
-        if exists:
-            seed = exists[0]
-        else:
-            session.add(seed)
-            session.commit()
         logger.debug(f'args.seed:\n{seed}')
     elif recent:
         seed = recent
         logger.debug(f'recent:\n{seed}')
     else:
         seed = ScrapNode(child=seed_shell)
+        logger.debug(f'seed_shell:\n{seed}')
+
+    exists = session.query(ScrapNode).filter(ScrapNode.checksum == seed.checksum).all()
+
+    if exists:
+        seed = exists[0]
+    else:
         session.add(seed)
         session.commit()
-        logger.debug(f'seed_shell:\n{seed}')
 
     parent = seed
     queue = Queue()