From d6bc09e2e9bb8cf4c6801e07d6a9bf561476eb2e Mon Sep 17 00:00:00 2001
From: Nikhil Parasaram <tommycjniko@gmail.com>
Date: Tue, 19 Jun 2018 20:46:09 +0530
Subject: [PATCH] add typecheck for the contracts

---
 mythril/laser/ethereum/natives.py | 18 ++++++++++++++----
 mythril/laser/ethereum/svm.py     | 16 +++++++++++-----
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/mythril/laser/ethereum/natives.py b/mythril/laser/ethereum/natives.py
index 98607165..e32ab81a 100644
--- a/mythril/laser/ethereum/natives.py
+++ b/mythril/laser/ethereum/natives.py
@@ -1,10 +1,11 @@
 # -*- coding: utf8 -*-
+
 import copy
 import hashlib
+
 import coincurve
 
 from py_ecc.secp256k1 import N as secp256k1n
-
 from mythril.laser.ethereum.helper import ALL_BYTES, bytearray_to_int, concrete_int_to_bytes, sha3, zpad
 
 
@@ -40,7 +41,10 @@ def extract32(data, i):
 
 
 def ecrecover(data):
-    data = bytearray(data)
+    try:
+        data = bytearray(data)
+    except TypeError:
+        return "ecrecover_"+str(data)
     message = b''.join(map(lambda x: ALL_BYTES[x], data[0:32]))
     v = extract32(data, 32)
     r = extract32(data, 64)
@@ -56,12 +60,18 @@ def ecrecover(data):
 
 
 def sha256(data):
-    data = bytes(data)
+    try:
+        data = bytes(data)
+    except TypeError:
+        return "sha256_"+str(data)
     return hashlib.sha256(data).digest()
 
 
 def ripemd160(data):
-    data = bytes(data)
+    try:
+        data = bytes(data)
+    except TypeError:
+        return "ripemd160_"+str(data)
     return 12*[0]+[i for i in hashlib.new('ripemd160', data).digest()]
 
 
diff --git a/mythril/laser/ethereum/svm.py b/mythril/laser/ethereum/svm.py
index d2f003ee..1c24eeaf 100644
--- a/mythril/laser/ethereum/svm.py
+++ b/mythril/laser/ethereum/svm.py
@@ -994,12 +994,14 @@ class LaserEVM:
                         state.stack.append(ret)
                         continue
 
-                if int(callee_address, 16) < 5 and int(callee_address, 16) > 0:
+                if 0 < int(callee_address, 16) < 5:
 
                     logging.info("Native contract called: " + callee_address)
                     calldata, calldata_type = self._get_calldata(meminstart, meminsz, state, pad=False)
                     if calldata == [] and calldata_type == CalldataType.SYMBOLIC:
                         logging.debug("CALL with symbolic data not supported")
+                        ret = BitVec("retval_" + str(instr['address']), 256)
+                        state.stack.append(ret)
                         continue
 
                     data = natives.native_contracts(int(callee_address, 16 ), calldata)
@@ -1008,14 +1010,18 @@ class LaserEVM:
                         mem_out_sz = memoutsz.as_long()
                     except AttributeError:
                         logging.debug("CALL with symbolic start or offset not supported")
+                        ret = BitVec("retval_" + str(instr['address']), 256)
+                        state.stack.append(ret)
                         continue
 
                     state.mem_extend(mem_out_start, mem_out_sz)
-                    for i in range(min(len(data), mem_out_sz)):     # If more data is used then it's chopped off
-                        state.memory[mem_out_start+i] = data[i]
+                    try:
+                        for i in range(min(len(data), mem_out_sz)):     # If more data is used then it's chopped off
+                            state.memory[mem_out_start+i] = data[i]
+                    except:
+                       state.memory[mem_out_start] = BitVec(data, 256)
+                    state.stack.append(1)
 
-                    ret = BitVec("retval_" + str(instr['address']), 256)
-                    state.stack.append(ret)
                     continue
 
                 try: