Changed instructions out-of-bounds behavior to return halt instruction. (#1223)

mythril/laser/ethereum/evm_exceptions.py

@@ -41,9 +41,3 @@ class WriteProtection(VmException):
     """A VM exception denoting that a write operation is executed on a write protected environment"""
 
     pass
-
-
-class ProgramCounterException(VmException):
-    """A VM exception denoting an invalid PC value (No stop instruction is reached)."""
-
-    pass

mythril/laser/ethereum/state/global_state.py

@@ -9,7 +9,6 @@ from mythril.laser.ethereum.cfg import Node
 from mythril.laser.ethereum.state.environment import Environment
 from mythril.laser.ethereum.state.machine_state import MachineState
 from mythril.laser.ethereum.state.annotation import StateAnnotation
-from mythril.laser.ethereum.evm_exceptions import ProgramCounterException
 
 if TYPE_CHECKING:
     from mythril.laser.ethereum.state.world_state import WorldState
@@ -95,13 +94,12 @@ class GlobalState:
 
         :return:
         """
-
         instructions = self.environment.code.instruction_list
-        if self.mstate.pc >= len(instructions):
+        try:
-            raise ProgramCounterException(
+            return instructions[self.mstate.pc]
-                "PC: {} can not be reached.".format(self.mstate.pc)
+        except KeyError:
-            )
+            new_instruction = {"address": self.mstate.pc, "opcode": "STOP"}
-        return instructions[self.mstate.pc]
+            return new_instruction
 
     @property
     def current_transaction(