def get_call_from_state(state: GlobalState) -> Union[Call, None]:
"""
:param state:
:return:
"""
instruction = state.get_current_instruction()
op = instruction["opcode"]
stack = state.mstate.stack
if op in ("CALL", "CALLCODE"):
gas, to, value, meminstart, meminsz, memoutstart, memoutsz = (
get_variable(stack[-1]),
get_variable(stack[-2]),
get_variable(stack[-3]),
get_variable(stack[-4]),
get_variable(stack[-5]),
get_variable(stack[-6]),
get_variable(stack[-7]),
)
if to.type == VarType.CONCRETE and to.val < 5:
return None
if meminstart.type == VarType.CONCRETE and meminsz.type == VarType.CONCRETE:
return Call(
state.node,
state,
None,
op,
to,
gas,
value,
state.mstate.memory[meminstart.val:meminsz.val * 4],
)
else:
return Call(state.node, state, None, op, to, gas, value)
else:
gas, to, meminstart, meminsz, memoutstart, memoutsz = (
get_variable(stack[-1]),
get_variable(stack[-2]),
get_variable(stack[-3]),
get_variable(stack[-4]),
get_variable(stack[-5]),
get_variable(stack[-6]),
)
return Call(state.node, state, None, op, to, gas)
def test_concrete_call_symbolic_to():
# arrange
address = "0x10"
active_account = Account(address)
active_account.code = Disassembly("00")
environment = Environment(active_account, None, None, None, None, None)
state = GlobalState(None, environment, None)
state.mstate.memory = ["placeholder", "calldata_bling_0"]
node = Node("example")
node.contract_name = "the contract name"
node.function_name = "the function name"
to = Variable("calldata_3", VarType.SYMBOLIC)
meminstart = Variable(1, VarType.CONCRETE)
call = Call(node, state, None, None, to, None)
# act
issues = _concrete_call(call, state, address, meminstart)
# assert
issue = issues[0]
assert issue.address == address
assert issue.contract == node.contract_name
assert issue.function == node.function_name
assert issue.title == "Call data forwarded with delegatecall()"
assert issue.type == "Informational"
assert (
issue.description
== "This contract forwards its call data via DELEGATECALL in its fallback function."
" This means that any function in the called contract can be executed."
" Note that the callee contract will have access to the storage of the "
"calling contract.\n DELEGATECALL target: calldata_3"
)
def test_delegate_call(sym_mock, concrete_mock, curr_instruction):
# arrange
# sym_mock = mocker.patch.object(delegatecall, "_symbolic_call")
# concrete_mock = mocker.patch.object(delegatecall, "_concrete_call")
sym_mock.return_value = []
concrete_mock.return_value = []
curr_instruction.return_value = {"address": "0x10"}
active_account = Account("0x10")
active_account.code = Disassembly("00")
environment = Environment(active_account, None, None, None, None, None)
state = GlobalState(None, environment, Node)
state.mstate.memory = ["placeholder", "calldata_bling_0"]
state.mstate.stack = [1, 2, 3]
assert state.get_current_instruction() == {"address": "0x10"}
node = Node("example")
node.contract_name = "the contract name"
node.function_name = "fallback"
to = Variable("storage_1", VarType.SYMBOLIC)
call = Call(node, state, None, "DELEGATECALL", to, None)
statespace = MagicMock()
statespace.calls = [call]
# act
execute(statespace)
# assert
assert concrete_mock.call_count == 1
assert sym_mock.call_count == 1
def test_concrete_call():
# arrange
address = "0x10"
state = GlobalState(None, None)
state.mstate.memory = ["placeholder", "calldata_bling_0"]
node = Node("example")
node.contract_name = "the contract name"
node.function_name = "the function name"
to = Variable(1, VarType.CONCRETE)
meminstart = Variable(1, VarType.CONCRETE)
call = Call(node, state, None, None, to, None)
# act
issues = _concrete_call(call, state, address, meminstart)
# assert
issue = issues[0]
assert issue.address == address
assert issue.contract == node.contract_name
assert issue.function == node.function_name
assert issue.title == "Call data forwarded with delegatecall()"
assert issue.type == 'Informational'
assert issue.description == "This contract forwards its call data via DELEGATECALL in its fallback function." \
" This means that any function in the called contract can be executed." \
" Note that the callee contract will have access to the storage of the " \
"calling contract.\n DELEGATECALL target: 0x1"
def test_symbolic_call_storage_to(mocker):
# arrange
address = "0x10"
active_account = Account(address)
environment = Environment(active_account, None, None, None, None, None)
state = GlobalState(None, environment)
state.mstate.memory = ["placeholder", "calldata_bling_0"]
node = Node("example")
node.contract_name = "the contract name"
node.function_name = "the function name"
to = Variable("storage_1", VarType.SYMBOLIC)
call = Call(node, state, None, "Type: ", to, None)
mocker.patch.object(SymExecWrapper, "__init__", lambda x, y: None)
statespace = SymExecWrapper(1)
mocker.patch.object(statespace, 'find_storage_write')
statespace.find_storage_write.return_value = "Function name"
# act
issues = _symbolic_call(call, state, address, statespace)
# assert
issue = issues[0]
assert issue.address == address
assert issue.contract == node.contract_name
assert issue.function == node.function_name
assert issue.title == 'Type: to a user-supplied address'
assert issue.type == 'Informational'
assert issue.description == 'This contract delegates execution to a contract address in storage slot 1.' \
' This storage slot can be written to by calling the function `Function name`. ' \
'Be aware that the called contract gets unrestricted access to this contract\'s state.'
def test_symbolic_call_calldata_to(mocker):
# arrange
address = "0x10"
state = GlobalState(None, None, None)
state.mstate.memory = ["placeholder", "calldata_bling_0"]
node = Node("example")
node.contract_name = "the contract name"
node.function_name = "the function name"
to = Variable("calldata", VarType.SYMBOLIC)
call = Call(node, state, None, "Type: ", to, None)
mocker.patch.object(SymExecWrapper, "__init__", lambda x, y: None)
statespace = SymExecWrapper(1)
mocker.patch.object(statespace, "find_storage_write")
statespace.find_storage_write.return_value = "Function name"
# act
issues = _symbolic_call(call, state, address, statespace)
# assert
issue = issues[0]
assert issue.address == address
assert issue.contract == node.contract_name
assert issue.function == node.function_name
assert issue.title == "Type: to a user-supplied address"
assert issue.type == "Informational"
assert (
issue.description ==
"This contract delegates execution to a contract address obtained from calldata. "
"Be aware that the called contract gets unrestricted access to this contract's state."
)
def test_delegate_call_not_fallback(sym_mock, concrete_mock):
# arrange
# sym_mock = mocker.patch.object(delegatecall, "_symbolic_call")
# concrete_mock = mocker.patch.object(delegatecall, "_concrete_call")
sym_mock.return_value = []
concrete_mock.return_value = []
node = Node("example")
node.function_name = "not_fallback"
to = Variable("storage_1", VarType.SYMBOLIC)
call = Call(node, None, None, "DELEGATECALL", to, None)
statespace = MagicMock()
statespace.calls = [call]
# act
issues = execute(statespace)
# assert
assert issues == []
assert concrete_mock.call_count == 0
assert sym_mock.call_count == 0