Adds concrete codecopy test

mythril/laser/ethereum/instructions.py

@@ -549,7 +549,7 @@ class Instruction:
         for i in range(concrete_size):
             try:
                 global_state.mstate.memory[concrete_memory_offset + i] =\
-                    int(bytecode[concrete_code_offset + i: concrete_code_offset + i + 2], 16)
+                    int(bytecode[2*(concrete_code_offset + i): 2*(concrete_code_offset + i + 1)], 16)
             except IndexError:
                 global_state.mstate.memory[concrete_memory_offset + i] = \
                     BitVec("code({})".format(global_state.environment.active_account.contract_name), 256)

tests/instructions/codecopy_test.py

@@ -0,0 +1,20 @@
+from mythril.disassembler.disassembly import Disassembly
+from mythril.laser.ethereum.state import MachineState, GlobalState, Environment, Account
+from mythril.laser.ethereum.instructions import Instruction
+
+
+def test_codecopy_concrete():
+    # Arrange
+    active_account = Account("0x0", code= Disassembly("60606040"))
+    environment = Environment(active_account, None, None, None, None, None)
+    og_state = GlobalState(None, environment, None, MachineState(gas=10000000))
+
+    og_state.mstate.stack = [2, 2, 2]
+    instruction = Instruction("codecopy", dynamic_loader=None)
+
+    # Act
+    new_state = instruction.evaluate(og_state)[0]
+
+    # Assert
+    assert new_state.mstate.memory[2] == 96
+    assert new_state.mstate.memory[3] == 64