def native_call(
global_state: GlobalState,
callee_address: Union[str, BitVec],
call_data: BaseCalldata,
memory_out_offset: Union[int, Expression],
memory_out_size: Union[int, Expression],
) -> Optional[List[GlobalState]]:
if (
isinstance(callee_address, BitVec)
or not 0 < int(callee_address, 16) <= PRECOMPILE_COUNT
):
return None
log.debug("Native contract called: " + callee_address)
try:
mem_out_start = util.get_concrete_int(memory_out_offset)
mem_out_sz = util.get_concrete_int(memory_out_size)
except TypeError:
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],
)
global_state.mstate.min_gas_used += native_gas_min
global_state.mstate.max_gas_used += native_gas_max
global_state.mstate.mem_extend(mem_out_start, mem_out_sz)
try:
data = natives.native_contracts(call_address_int, call_data)
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
)
return [global_state]
for i in range(
min(len(data), mem_out_sz)
): # If more data is used then it's chopped off
global_state.mstate.memory[mem_out_start + i] = data[i]
retval = global_state.new_bitvec(
"retval_" + str(global_state.get_current_instruction()["address"]), 256
)
global_state.mstate.stack.append(retval)
global_state.node.constraints.append(retval == 1)
return [global_state]
def __init__(self, call_state: GlobalState, constraints: List) -> None:
"""
Initialize DelegateCall Annotation
:param call_state: Call state
"""
self.call_state = call_state
self.constraints = constraints
self.return_value = call_state.new_bitvec(
"retval_{}".format(call_state.get_current_instruction()["address"]), 256
)