def testReplace(self):
old_env = env.Env(b"")
new_env = old_env.clean_copy()
state = State(new_env)
state.storage_written[old_env.caller] = old_env.value
state.replace(functools.partial(env.replace, old_env, state.env))
self.assertIs(state.storage_written[new_env.caller], new_env.value)
def test_sha3_key(self):
"""Exercise solidity-like mappings, with the key being a sha3."""
state = State(self.env)
state_write = state.copy()
# Arbitrary write input[1], at SHA3(input[0])
state_write.storage_written = {
Sha3(self.env.calldata.read(4, 32)): self.env.calldata.read(36, 32)
}
# Needs that: storage[SHA3(input[0])] == 43, made possible by the previous call
state_selfdestruct = state.copy()
state_selfdestruct.selfdestruct_to = self.env.calldata.read(36, 32)
storage_input = claripy.BVS("storage[SHA3(input)]", 256)
state_selfdestruct.storage_read = {
Sha3(self.env.calldata.read(4, 32)): storage_input
}
state_selfdestruct.solver.add(storage_input == 0xDEADBEEF101010)
storage = {
55186156870478567193644641351382124067713781048612400765092754877653207859685: 0
}
self.assertTrue(
self.check_states([state_write, state_selfdestruct], mock_storage=storage)
)
self.assertFalse(self.check_states([state_selfdestruct], mock_storage=storage))
self.assertFalse(self.check_states([state_write]))
def test_write_write_and_selfdestruct(self):
state = State(self.env)
# Anybody can set owner
state_write1 = state.copy()
state_write1.storage_written = {utils.bvv(0): self.env.calldata.read(4, 32)}
# Onlyowner: set a magic constant allowing the selfdestruct bug, at an
# user-controlled storage key.
state_write2 = state.copy()
read_0 = claripy.BVS("storage[0]", 256)
state_write2.storage_read = {utils.bvv(0): read_0}
state_write2.storage_written = {
self.env.calldata.read(36, 32): self.env.calldata.read(4, 32)
}
state_write2.solver.add(read_0 == self.env.caller)
# Suicide, when owner and magic constant set
state_selfdestruct = state.copy()
read_0 = claripy.BVS("storage[0]", 256)
read_40 = claripy.BVS("storage[4]", 256)
state_selfdestruct.storage_read = {utils.bvv(0): read_0, utils.bvv(40): read_40}
state_selfdestruct.solver.add(self.env.caller == read_0)
state_selfdestruct.solver.add(read_40 == 1337)
state_selfdestruct.selfdestruct_to = self.env.caller
states = [state_write1, state_write2, state_selfdestruct]
random.shuffle(states)
storage = {0: 123456789, 40: 387642}
for s in itertools.combinations(states, 2):
self.assertFalse(self.check_states(s, mock_storage=storage))
self.assertTrue(self.check_states(states, mock_storage=storage))
def test_sha3_value2(self):
"""Same as above, but we need to pass the computed SHA3."""
state = State(self.env)
state_write = state.copy()
state_write.storage_written = {
utils.bvv(0): Sha3(self.env.calldata.read(4, 32))
}
state_selfdestruct = state.copy()
state_selfdestruct.selfdestruct_to = self.env.calldata.read(36, 32)
storage_input = claripy.BVS("storage[0]", 256)
state_selfdestruct.storage_read = {utils.bvv(0): storage_input}
state_selfdestruct.solver.add(
storage_input == self.env.calldata.read(4, 32))
state_selfdestruct.solver.add(storage_input != 0)
storage = {0: 0}
self.assertTrue(
self.check_states([state_write, state_selfdestruct],
mock_storage=storage))
self.assertFalse(
self.check_states([state_selfdestruct], mock_storage=storage))
self.assertFalse(self.check_states([state_write],
mock_storage=storage))
def test_symbolic_storage(self):
"""Specific test for using a storage key that cannot be symbolized."""
state = State(self.env)
storage = {10: 1}
# We write to an arbitrary address
state_write = state.copy()
state_write.storage_written[state_write.env.calldata.read(
4, 32)] = state_write.env.calldata.read(36, 32)
# We send twice what we receive, but only if we have 1 at two arbitrary
# keys.
state_send = state.copy()
storage_a = claripy.BVS("storage[a]", 256)
storage_b = claripy.BVS("storage[b]", 256)
k_a = state_send.env.calldata.read(4, 32)
k_b = state_send.env.calldata.read(36, 32)
state_send.storage_read[k_a] = storage_a
state_send.storage_read[k_b] = storage_b
state_send.solver.add(storage_a == 1)
state_send.solver.add(storage_b == 1)
state_send.calls.append(self.get_call((state.env.value * 128) / 64))
# If k_a == 10 and k_b == 10, it works!
self.assertTrue(self.check_states([state_send], mock_storage=storage))
state_send.solver.add(k_a != k_b)
self.assertFalse(self.check_states([state_send], mock_storage=storage))
self.assertFalse(self.check_states([state_write],
mock_storage=storage))
# Now we have to first write, then send.
bug = self.check_states([state_send, state_write],
mock_storage=storage)
self.assertTrue(bug)
self.assertEqual(len(bug[1]), 2)
# If we force k_a to be != 10, we can use k_b == 10 instead.
state_send.solver.add(k_a != 10)
bug = self.check_states([state_send, state_write],
mock_storage=storage)
self.assertTrue(bug)
self.assertEqual(len(bug[1]), 2)
# If we force both, it's impossible and we have to do two writes.
state_send.solver.add(k_b != 10)
bug = self.check_states([state_send, state_write],
mock_storage=storage)
self.assertTrue(bug)
self.assertEqual(len(bug[1]), 3)
def testSameHashIfDifferentOrder(self):
a = State()
b = State()
self.assertEqual(hash(a), hash(b))
e = env.Env(b"")
a.solver.add(e.value == 1)
a.solver.add(e.block_timestamp == 2)
# Same thing, different order
b.solver.add(e.block_timestamp == 2)
b.solver.add(e.value == 1)
self.assertEqual(hash(a), hash(b))
def test_write_and_selfdestruct(self):
state = State(self.env)
state_write = state.copy()
state_write.storage_written = {utils.bvv(0): self.env.calldata.read(4, 32)}
state_selfdestruct = state.copy()
state_selfdestruct.selfdestruct_to = self.env.calldata.read(4, 32)
storage_0 = claripy.BVS("storage[0]", 256)
state_selfdestruct.storage_read = {utils.bvv(0): storage_0}
state_selfdestruct.solver.add(storage_0 == 0xDEADBEEF0101)
storage = {0: 0xBAD1DEA}
self.assertTrue(
self.check_states([state_write, state_selfdestruct], mock_storage=storage)
)
self.assertFalse(self.check_states([state_selfdestruct], mock_storage=storage))
self.assertFalse(self.check_states([state_write]))
def setUp(self):
self.env = Env(b"",
caller=utils.DEFAULT_CALLER,
address=utils.DEFAULT_ADDRESS)
self.state = State(self.env)
self.analyzer = Analyzer(
address=self.env.address,
caller=self.env.caller,
max_wei_to_send=Web3.toWei(10, "ether"),
min_wei_to_receive=Web3.toWei(1, "milliether"),
)
def check_states(self, states, timeout, max_depth):
states = [state for state in states if state.is_interesting()]
if not states:
return
# Each state must have its own independent environment
assert not self.reference_states
# For each state, a list of equivalent state, but each in a different
# env so that they can be stacked together.
self.reference_states = []
for state in states:
self.reference_states.append(
[with_new_env(state) for _ in range(max_depth)])
# Add it to the paths to explore
self.path_queue.append((State(), [self.reference_states[-1][0]]))
# Recursive exploration
last_path_len = 0
time_start = time.process_time()
while self.path_queue:
initial_composite_state, path = self.path_queue.popleft()
if len(path) > last_path_len:
logger.log(
utils.INFO_INTERACTIVE,
"Now scanning paths of length %i.",
len(path),
)
last_path_len = len(path)
if len(path) > max_depth:
logger.debug("Over the max allowed depth, stopping.")
return
if DEBUG_MARK_PATH and all(
is_function(s, f) for s, f in zip(path, DEBUG_MARK_PATH)):
logger.warning("DEBUG_MARK_PATH len %i", len(path))
logger.warning("path: %s", path)
breakpoint()
new_composite_states = self._append_state(initial_composite_state,
path[-1])
for composite_state in new_composite_states:
solver = self._search_path(composite_state, path)
if solver is not None:
return composite_state, path, solver
if timeout and time.process_time() - time_start > timeout:
logger.debug("Timeout at depth %i, stopping.", len(path))
return
def test_env_replace_merge_with_recursive_hash(self):
old_env = env.Env(b"")
new_env = old_env.clean_copy()
old_state = State(old_env)
old_state.solver.add(Sha3(Sha3(old_env.caller)) == Sha3(old_env.value))
self.assertTrue(old_state.solver.satisfiable())
self.assertFalse(
old_state.solver.satisfiable(
extra_constraints=[old_env.value == 5]))
new_state = old_state.copy()
new_state.replace(functools.partial(env.replace, old_env, new_env))
new_state.replace(new_state.solver.regenerate_hash_symbols())
self.assertTrue(new_state.solver.satisfiable())
self.assertFalse(
new_state.solver.satisfiable(
extra_constraints=[new_env.value == 5]))
self.assertTrue(
new_state.solver.satisfiable(
extra_constraints=[old_env.value == 5]))
new_state.solver.add(old_env.value == new_env.value)
self.assertTrue(new_state.solver.satisfiable())
self.assertFalse(
new_state.solver.satisfiable(
extra_constraints=[new_env.value == 5]))
self.assertFalse(
new_state.solver.satisfiable(
extra_constraints=[old_env.value == 5]))
old_state.solver = old_state.solver.combine([new_state.solver])
self.assertTrue(new_state.solver.satisfiable())
self.assertEqual(len(old_state.solver.constraints), 3)
self.assertEqual(len(old_state.solver.hashes),
len(new_state.solver.hashes) * 2)
def test_sha3_value1(self):
"""Exercise comparison of two SHA3 (as values)."""
state = State(self.env)
state_write = state.copy()
state_write.storage_written = {
utils.bvv(0): Sha3(self.env.calldata.read(4, 32))
}
state_selfdestruct = state.copy()
state_selfdestruct.selfdestruct_to = self.env.calldata.read(36, 32)
storage_input = claripy.BVS("storage[0]", 256)
state_selfdestruct.storage_read = {utils.bvv(0): storage_input}
state_selfdestruct.solver.add(
storage_input == Sha3(self.env.calldata.read(4, 32))
)
storage = {0: 0}
self.assertTrue(
self.check_states([state_write, state_selfdestruct], mock_storage=storage)
)
self.assertFalse(self.check_states([state_selfdestruct], mock_storage=storage))
self.assertFalse(self.check_states([state_write], mock_storage=storage))
def __init__(self, env):
self.code = env.code
logger.debug("Initializing symbolic machine with source code: %s",
self.code)
# For use by heapq only. Contains couples (score, state).
self.branch_queue = []
self.states_seen = set()
self.coverage = [0] * len(self.code)
# List of all normal/good terminations of the contract
self.outcomes = []
# List of all the place where we didn't know how to continue execution
self.partial_outcomes = []
self.fuzz = True
self.code_errors = collections.Counter()
self.interpreter_errors = collections.Counter()
self.add_branch(State(env))
def test_with_new_env(self):
env = Env(b"")
state = State(env)
storage_0 = claripy.BVS("storage[0]", 256)
storage_1 = claripy.BVS("storage[0]", 256)
storage_2 = claripy.BVS("storage[0]", 256)
state.storage_read[utils.bvv(0)] = storage_0
state.storage_read[utils.bvv(1)] = storage_1
state.storage_read[utils.bvv(2)] = storage_2
state.storage_written[utils.bvv(0)] = utils.bvv(0)
state.storage_written[utils.bvv(1)] = utils.bvv(0)
state.storage_written[utils.bvv(2)] = utils.bvv(0)
state.calls.append([
utils.bvv(1),
storage_0 + storage_1 + storage_2,
utils.bvv(2),
5 * (storage_0 + storage_1 + storage_2),
])
state.solver.add(storage_0 == 42)
state.solver.add(storage_1 == 0)
state.solver.add(storage_2 == 0)
self.assertEqual(state.solver.eval(state.calls[0][1], 2), (42, ))
for i in range(3):
new_state = with_new_env(state)
self.assertIsNot(state.env.value, new_state.env.value)
self.assertIsNot(state.storage_read[utils.bvv(0)],
new_state.storage_read[utils.bvv(0)])
self.assertIsNot(state.storage_read[utils.bvv(1)],
new_state.storage_read[utils.bvv(1)])
self.assertIsNot(state.storage_read[utils.bvv(2)],
new_state.storage_read[utils.bvv(2)])
self.assertNotEqual(new_state.solver.eval(state.calls[0][1], 2),
(42, ))
self.assertEqual(new_state.solver.eval(new_state.calls[0][1], 2),
(42, ))
def __init__(self, env, fuzz=True):
self.code = env.code
logger.debug("Initializing symbolic machine with source code: %s",
self.code)
# For use by heapq only. Contains couples (score, state).
self.branch_queue = []
self.states_seen = set()
self.coverage = [0] * len(self.code)
# List of all normal/good terminations of the contract
self.outcomes = []
# List of all the place where we didn't know how to continue execution
self.partial_outcomes = []
# Do we want to enable fuzzing? (see add_for_fuzzing below)
self.fuzz = fuzz
# Did fuzzing got used?
self.fuzzed = False
# Errors that happened during execution. These are normal.
self.code_errors = collections.Counter()
# Errors of the interpreter / symbolic execution engine. Not cool :(
self.interpreter_errors = collections.Counter()
self.add_branch(State(env))
def testHashWorks(self):
state = State(env.Env(b""))
state.pc = 5
state.memory.write(0, 1, claripy.BVV(42, 8))
state.memory.write(10, 1, claripy.BVV(43, 8))
state.memory.write(20, 1, claripy.BVV(44, 8))
state_copy = state.copy()
self.assertEqual(hash(state), hash(state_copy))
state.pc = 6
self.assertNotEqual(hash(state), hash(state_copy))
state_copy.pc = 6
self.assertEqual(hash(state), hash(state_copy))
state.memory.write(10, 1, claripy.BVV(45, 8))
self.assertNotEqual(hash(state), hash(state_copy))
state_copy.memory.write(10, 1, claripy.BVV(45, 8))
self.assertEqual(hash(state), hash(state_copy))
state.stack_push(state.env.calldata.read(0, 1))
self.assertNotEqual(hash(state), hash(state_copy))
state_copy.stack_push(state_copy.env.calldata.read(0, 1))
self.assertEqual(hash(state), hash(state_copy))
def test_call_simple(self):
state = State(self.env)
state.calls.append(self.get_call(self.env.balance))
self.assertTrue(self.check_states([state]))
def test_selfdestruct_simple(self):
state = State(self.env)
state.selfdestruct_to = self.env.caller
self.assertTrue(self.check_states([state]))
def test_simple(self):
state = State(self.env)
self.assertFalse(self.check_states([state]))
def test_send_after_write(self):
state = State(self.env)
# We send storage[0]
state_send = state.copy()
storage_0 = claripy.BVS("storage[0]", 256)
state_send.storage_read = {utils.bvv(0): storage_0}
state_send.calls.append(self.get_call(storage_0))
# storage[0] is 0.5 ETH
storage = {0: Web3.toWei(0.5, "ether")}
self.assertTrue(self.check_states([state_send], mock_storage=storage))
# storage[0] is 0 ETH
storage = {0: 0}
self.assertFalse(self.check_states([state_send], mock_storage=storage))
# storage[0] is still 0 ETH initially, but we have an arbitrary write now
state_write = state.copy()
state_write.storage_written = {utils.bvv(0): self.env.calldata.read(4, 32)}
state_write.solver.add(self.env.calldata.read(0, 4) == 0x1337)
state_write.solver.add(self.env.calldata.read(4, 32) < Web3.toWei(1, "ether"))
self.assertFalse(self.check_states([state_write], mock_storage=storage))
self.assertTrue(
self.check_states([state_send, state_write], mock_storage=storage)
)
self.assertTrue(
self.check_states([state_write, state_send], mock_storage=storage)
)
# ...arbitrary write of 1 wei only, which is too little
state_write_0 = state_write.copy()
state_write_0.solver.add(self.env.calldata.read(4, 32) == 1)
self.assertFalse(
self.check_states([state_write_0, state_send], mock_storage=storage)
)
# ...arbitrary write only if the block timestamp is <10, which is impossible.
state_write_ts = state_write.copy()
state_write_ts.solver.add(self.env.block_timestamp < 10)
self.assertFalse(
self.check_states([state_write_ts, state_send], mock_storage=storage)
)
self.assertFalse(
self.check_states(
[state_write_0, state_send, state_write_ts], mock_storage=storage
)
)
# now we put all these state_write* together, so there is a solution.
self.assertTrue(
self.check_states(
[state_write_0, state_send, state_write, state_write_ts],
mock_storage=storage,
)
)
self.assertTrue(
self.check_states(
[state_write_0, state_write, state_write_ts, state_send],
mock_storage=storage,
)
)