Fix/natives (#1302)

* Fix precompiles

* Fix black

* Deal with TypeError

mythril/laser/ethereum/call.py

@@ -10,7 +10,7 @@ import mythril.laser.ethereum.util as util
 from mythril.laser.ethereum import natives
 from mythril.laser.ethereum.instruction_data import calculate_native_gas
 from mythril.laser.ethereum.state.account import Account
-from mythril.laser.ethereum.natives import PRECOMPILE_COUNT
+from mythril.laser.ethereum.natives import PRECOMPILE_COUNT, PRECOMPILE_FUNCTIONS
 from mythril.laser.ethereum.state.calldata import (
     BaseCalldata,
     SymbolicCalldata,
@@ -249,11 +249,10 @@ def native_call(
         log.debug("CALL with symbolic start or offset not supported")
         return [global_state]
 
-    contract_list = ["ecrecover", "sha256", "ripemd160", "identity"]
     call_address_int = int(callee_address, 16)
     native_gas_min, native_gas_max = calculate_native_gas(
         global_state.mstate.calculate_extension_size(mem_out_start, mem_out_sz),
-        contract_list[call_address_int - 1],
+        PRECOMPILE_FUNCTIONS[call_address_int - 1].__name__,
     )
     global_state.mstate.min_gas_used += native_gas_min
     global_state.mstate.max_gas_used += native_gas_max
@@ -263,7 +262,11 @@ def native_call(
     except natives.NativeContractException:
         for i in range(mem_out_sz):
             global_state.mstate.memory[mem_out_start + i] = global_state.new_bitvec(
-                contract_list[call_address_int - 1] + "(" + str(call_data) + ")", 8
+                PRECOMPILE_FUNCTIONS[call_address_int - 1].__name__
+                + "("
+                + str(call_data)
+                + ")",
+                8,
             )
         return [global_state]
 

mythril/laser/ethereum/instruction_data.py

@@ -199,7 +199,7 @@ def calculate_native_gas(size: int, contract: str):
     :param contract:
     :return:
     """
-    gas_value = None
+    gas_value = 0
     word_num = ceil32(size) // 32
     if contract == "ecrecover":
         gas_value = opcodes.GECRECOVER
@@ -210,7 +210,9 @@ def calculate_native_gas(size: int, contract: str):
     elif contract == "identity":
         gas_value = opcodes.GIDENTITYBASE + word_num * opcodes.GIDENTITYWORD
     else:
-        raise ValueError("Unknown contract type {}".format(contract))
+        # TODO: Add gas for other precompiles, computation should be shifted to natives.py
+        #  as some data isn't available here
+        pass
     return gas_value, gas_value
 
 

mythril/laser/ethereum/natives.py

@@ -213,9 +213,10 @@ def native_contracts(address: int, data: BaseCalldata) -> List[int]:
     :return:
     """
 
-    if isinstance(data, ConcreteCalldata):
-        concrete_data = data.concrete(None)
-    else:
+    if not isinstance(data, ConcreteCalldata):
         raise NativeContractException()
-
-    return PRECOMPILE_FUNCTIONS[address - 1](concrete_data)
+    concrete_data = data.concrete(None)
+    try:
+        return PRECOMPILE_FUNCTIONS[address - 1](concrete_data)
+    except TypeError:
+        raise NativeContractException