From f1d88ff8186813e2c2ad3d431ac57329b9dd145a Mon Sep 17 00:00:00 2001
From: Bernhard Mueller <bernhard.mueller11@gmail.com>
Date: Sat, 20 Jan 2018 11:03:34 +0700
Subject: [PATCH] Add workaround to prevent crash when dynamic contract address
 is encountered in bytecode

---
 mythril/analysis/modules/integer_underflow.py | 3 ++-
 mythril/ether/ethcontract.py                  | 9 ++++++++-
 mythril/ether/util.py                         | 1 +
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/mythril/analysis/modules/integer_underflow.py b/mythril/analysis/modules/integer_underflow.py
index 1ae9d601..d74b930e 100644
--- a/mythril/analysis/modules/integer_underflow.py
+++ b/mythril/analysis/modules/integer_underflow.py
@@ -38,7 +38,8 @@ def execute(statespace):
                     continue
 
                 if (re.search(r'calldatasize_', str(op0))) \
-                    or (re.search(r'256\*.*If\(1', str(op0), re.DOTALL) or re.search(r'256\*.*If\(1', str(op1), re.DOTALL)):
+                    or (re.search(r'256\*.*If\(1', str(op0), re.DOTALL) or re.search(r'256\*.*If\(1', str(op1), re.DOTALL)) \
+                    or (re.search(r'32 \+.*calldata', str(op0), re.DOTALL) or re.search(r'32 \+.*calldata', str(op1), re.DOTALL)):
 
                     # Filter for patterns that contain possible (but apparently non-exploitable) Integer underflows.
 
diff --git a/mythril/ether/ethcontract.py b/mythril/ether/ethcontract.py
index 5a5f3ffe..dd5622d6 100644
--- a/mythril/ether/ethcontract.py
+++ b/mythril/ether/ethcontract.py
@@ -8,11 +8,18 @@ class ETHContract(persistent.Persistent):
 
     def __init__(self, code, creation_code="", name="", address=""):
 
-        self.code = code
         self.creation_code = creation_code
         self.name = name
         self.address = address
 
+        # Workaround: We currently do not support compile-time linking.
+        # Dynamic contract addresses of the format __[contract-name]_____________ are replaced with a generic address
+
+        code = re.sub(r'(_+[A-Za-z0-9]+_+)', 'aa' * 20, code)
+
+        self.code = code
+
+
     def as_dict(self):
 
         return {
diff --git a/mythril/ether/util.py b/mythril/ether/util.py
index 350e08c2..98c7f7d1 100644
--- a/mythril/ether/util.py
+++ b/mythril/ether/util.py
@@ -9,6 +9,7 @@ import re
 
 
 def safe_decode(hex_encoded_string):
+
     if (hex_encoded_string.startswith("0x")):
         return bytes.fromhex(hex_encoded_string[2:])
     else: