class Calldata:
"""
Calldata class representing the calldata of a transaction
"""
def __init__(self, tx_id, starting_calldata=None):
"""
Constructor for Calldata
:param tx_id: unique value representing the transaction the calldata is for
:param starting_calldata: byte array representing the concrete calldata of a transaction
"""
self.tx_id = tx_id
if starting_calldata is not None:
self._calldata = []
self.calldatasize = BitVecVal(len(starting_calldata), 256)
self.concrete = True
else:
self._calldata = Array("{}_calldata".format(self.tx_id),
BitVecSort(256), BitVecSort(8))
self.calldatasize = BitVec("{}_calldatasize".format(self.tx_id),
256)
self.concrete = False
if self.concrete:
for calldata_byte in starting_calldata:
if type(calldata_byte) == int:
self._calldata.append(BitVecVal(calldata_byte, 8))
else:
self._calldata.append(calldata_byte)
def concretized(self, model):
result = []
for i in range(
get_concrete_int(
model.eval(self.calldatasize, model_completion=True))):
result.append(
get_concrete_int(
model.eval(self._calldata[i], model_completion=True)))
return result
def get_word_at(self, index: int):
return self[index:index + 32]
def __getitem__(self, item: Union[int, slice]) -> Any:
if isinstance(item, slice):
start, step, stop = item.start, item.step, item.stop
try:
if start is None:
start = 0
if step is None:
step = 1
if stop is None:
stop = self.calldatasize
current_index = (start if isinstance(start, BitVecRef) else
BitVecVal(start, 256))
dataparts = []
while simplify(current_index != stop):
dataparts.append(self[current_index])
current_index = simplify(current_index + step)
except Z3Exception:
raise IndexError("Invalid Calldata Slice")
values, constraints = zip(*dataparts)
result_constraints = []
for c in constraints:
result_constraints.extend(c)
return simplify(Concat(values)), result_constraints
if self.concrete:
try:
return self._calldata[get_concrete_int(item)], ()
except IndexError:
return BitVecVal(0, 8), ()
else:
constraints = [
Implies(self._calldata[item] != 0, UGT(self.calldatasize,
item))
]
return self._calldata[item], constraints
class Calldata:
"""
Calldata class representing the calldata of a transaction
"""
def __init__(self, tx_id, starting_calldata=None):
"""
Constructor for Calldata
:param tx_id: unique value representing the transaction the calldata is for
:param starting_calldata: byte array representing the concrete calldata of a transaction
"""
self.tx_id = tx_id
if starting_calldata:
self._calldata = []
self.calldatasize = BitVecVal(len(starting_calldata), 256)
self.concrete = True
else:
self._calldata = Array("{}_calldata".format(self.tx_id),
BitVecSort(256), BitVecSort(8))
self.calldatasize = BitVec("{}_calldatasize".format(self.tx_id),
256)
self.concrete = False
self.starting_calldata = starting_calldata or []
@property
def constraints(self):
constraints = []
if self.concrete:
for calldata_byte in self.starting_calldata:
if type(calldata_byte) == int:
self._calldata.append(BitVecVal(calldata_byte, 8))
else:
self._calldata.append(calldata_byte)
constraints.append(
self.calldatasize == len(self.starting_calldata))
else:
x = BitVec("x", 256)
constraints.append(
ForAll(x, Implies(self[x] != 0, UGT(self.calldatasize, x))))
return constraints
def concretized(self, model):
result = []
for i in range(
get_concrete_int(
model.eval(self.calldatasize, model_completion=True))):
result.append(
get_concrete_int(model.eval(self[i], model_completion=True)))
return result
def get_word_at(self, index: int):
return self[index:index + 32]
def __getitem__(self, item):
if isinstance(item, slice):
try:
current_index = (item.start if isinstance(
item.start, BitVecRef) else BitVecVal(item.start, 256))
dataparts = []
while simplify(current_index != item.stop):
dataparts.append(self[current_index])
current_index = simplify(current_index + 1)
except Z3Exception:
raise IndexError("Invalid Calldata Slice")
return simplify(Concat(dataparts))
if self.concrete:
try:
return self._calldata[get_concrete_int(item)]
except IndexError:
return BitVecVal(0, 8)
else:
return self._calldata[item]