From 1125c34ddb4eddddf4dc423482cf72bbba24cdcb Mon Sep 17 00:00:00 2001
From: Bernhard Mueller <bernhard.mueller11@gmail.com>
Date: Sun, 30 Jun 2019 09:34:34 +0200
Subject: [PATCH] Modify loop detection to trigger after >2 iterations

---
 mythril/analysis/modules/dos.py | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/mythril/analysis/modules/dos.py b/mythril/analysis/modules/dos.py
index 14053991..36b9b940 100644
--- a/mythril/analysis/modules/dos.py
+++ b/mythril/analysis/modules/dos.py
@@ -19,7 +19,7 @@ class VisitsAnnotation(StateAnnotation):
 
     def __init__(self) -> None:
         self.loop_start = None
-        self.jump_targets = []  # type: List[int]
+        self.jump_targets = {}  # type: Dict[int]
 
     def __copy__(self):
         result = VisitsAnnotation()
@@ -76,13 +76,19 @@ class DOS(DetectionModule):
             annotation = annotations[0]
 
         if opcode in ["JUMP", "JUMPI"]:
+
+            if annotation.loop_start is not None:
+                return []
+
             target = util.get_concrete_int(state.mstate.stack[-1])
 
-            if annotation.loop_start is None:
-                if target in annotation.jump_targets:
-                    annotation.loop_start = address
-                else:
-                    annotation.jump_targets.append(target)
+            if target in annotation.jump_targets:
+                annotation.jump_targets[target] += 1
+            else:
+                annotation.jump_targets[target] = 1
+
+            if annotation.jump_targets[target] > 2:
+                annotation.loop_start = target
 
         elif annotation.loop_start is not None: