def add_for_fuzzing(self, state, variable, tries):
"""
Will try to fuzz the variable, setting it to different values.
The tries parameter must be an array of :
- min: if you want to add the minimum value possible
- max: if you want to add the maximum value possible
- a number: to try that number
- None: a random number that works, you can repeat it.
"""
# TODO: If the fuzzer is used, then I will generate tons of branches
# that are equivalent... There should be a way to deduplicate them,
# but it's not trivial.
if not self.fuzz:
raise utils.InterpreterError(state, "Fuzzer is disabled")
if not self.fuzzed:
self.fuzzed = True
logger.warning("Fuzzer got used (forced concretization). "
"We will lose accuracy and risk state explosion.")
to_try = set()
nb_random = 0
for t in tries: # pylint:disable=invalid-name
if isinstance(t, numbers.Number) and state.solver.solution(
variable, t):
to_try.add(t)
elif t is min:
to_try.add(state.solver.min(variable))
elif t is max:
to_try.add(state.solver.max(variable))
elif t is None:
nb_random += 1
if nb_random:
to_try |= set(state.solver.eval(variable, nb_random))
logger.debug("Fuzzing will try %s in %s.", variable, to_try)
state.depth += 1 if len(
to_try
) == 1 else 10 # Lower the priority of what we got by fuzzing.
for value in to_try:
new_state = state.copy()
new_state.solver.add(variable == value)
self.add_branch(new_state)
def write(self, addr, size, value):
if size < 1:
raise utils.CodeError("size < 1 in Memory.write")
if addr + size >= MEMORY_SIZE:
raise utils.CodeError("overflow in Memory.write")
if value.size() // 8 != size:
raise utils.InterpreterError("BVV size doesn't match size in Memory.write")
logger.debug(
"%s.write(%i, %i, %r)" % (self.__class__.__name__, addr, size, value)
)
for iaddr, ivalue in list(self._mem.items()):
isize = ivalue.size() // 8
raddr = iaddr - addr
rend = iaddr + isize - addr
# equal
if raddr == 0 and rend == size:
break
# completely overlaps
elif raddr <= 0 and rend >= size:
if raddr < 0:
self._mem[iaddr] = _slice(ivalue, 0, -raddr)
self._mem[addr + size] = _slice(ivalue, -raddr + size, None)
# completely inside (not strictly)
elif raddr >= 0 and rend <= size:
del self._mem[iaddr]
# end inside
elif 0 < rend < size:
self._mem[iaddr] = _slice(ivalue, 0, -raddr)
# start inside
elif 0 < raddr < size:
del self._mem[iaddr]
self._mem[addr + size] = _slice(ivalue, size - raddr, None)
self._mem[addr] = value
def exec_branch(self, state): # pylint:disable=invalid-name
"""Execute forward from a state, queuing new states if needed."""
logger.debug("Constraints: %s", state.solver.constraints)
def solution(variable):
"""Returns the solution. There must be one or we fail."""
solutions = state.solver.eval(variable, 2)
if len(solutions) > 1:
raise MultipleSolutionsError(
"Multiple solutions for %s (%#x)" %
(variable, self.code[state.pc]))
solution = solutions[0]
return solution if isinstance(solution,
numbers.Number) else solution.value
self.code.pc = state.pc
while True:
if state.pc >= len(self.code):
return True
op = self.code[state.pc]
self.code.pc += 1
self.coverage[state.pc] += 1
logger.debug("NEW STEP")
logger.debug("Memory: %s", state.memory)
logger.debug("Stack: %s", state.stack)
logger.debug("PC: %i, %#x", state.pc, op)
assert self.code.pc == state.pc + 1
assert isinstance(op, numbers.Number)
assert all(
isinstance(i, claripy.ast.base.BV) for i in
state.stack), "The stack musty only contains claripy BV's"
# Trivial operations first
if not self.code.is_valid_opcode(state.pc):
raise utils.CodeError("Trying to execute PUSH data")
elif op == 254: # INVALID opcode
raise utils.CodeError("designed INVALID opcode")
elif op == opcode_values.JUMPDEST:
pass
elif op == opcode_values.ADD:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(s0 + s1)
elif op == opcode_values.SUB:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(s0 - s1)
elif op == opcode_values.MUL:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(s0 * s1)
elif op == opcode_values.DIV:
# We need to use claripy.LShR instead of a division if possible,
# because the solver is bad dealing with divisions, better
# with shifts. And we need shifts to handle the solidity ABI
# for function selection.
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1) # pylint:disable=invalid-name
except MultipleSolutionsError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0 / s1))
else:
if s1 == 0:
state.stack_push(BVV_0)
elif s1 == 1:
state.stack_push(s0)
elif s1 & (s1 - 1) == 0:
exp = int(math.log(s1, 2))
state.stack_push(s0.LShR(exp))
else:
state.stack_push(s0 / s1)
elif op == opcode_values.SDIV:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1)
except MultipleSolutionsError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0.SDiv(s1)))
else:
state.stack_push(BVV_0 if s1 == 0 else s0.SDiv(s1))
elif op == opcode_values.MOD:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1)
except MultipleSolutionsError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0 % s1))
else:
state.stack_push(BVV_0 if s1 == 0 else s0 % s1)
elif op == opcode_values.SMOD:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1)
except MultipleSolutionsError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0.SMod(s1)))
else:
state.stack_push(BVV_0 if s1 == 0 else s0.SMod(s1))
elif op == opcode_values.ADDMOD:
s0, s1, s2 = state.stack_pop(), state.stack_pop(
), state.stack_pop()
try:
s2 = solution(s2)
except MultipleSolutionsError:
state.stack_push(claripy.If(s2 == 0, BVV_0,
(s0 + s1) % s2))
else:
state.stack_push(BVV_0 if s2 == 0 else (s0 + s1) % s2)
elif op == opcode_values.MULMOD:
s0, s1, s2 = state.stack_pop(), state.stack_pop(
), state.stack_pop()
try:
s2 = solution(s2)
except MultipleSolutionsError:
state.stack_push(claripy.If(s2 == 0, BVV_0,
(s0 * s1) % s2))
else:
state.stack_push(BVV_0 if s2 == 0 else (s0 * s1) % s2)
elif op == opcode_values.SHL:
shift, value = state.stack_pop(), state.stack_pop()
state.stack_push(value << shift)
elif op == opcode_values.SHR:
shift, value = state.stack_pop(), state.stack_pop()
state.stack_push(value.LShR(shift))
elif op == opcode_values.SAR:
shift, value = state.stack_pop(), state.stack_pop()
state.stack_push(claripy.RotateRight(value, shift))
elif op == opcode_values.EXP:
base, exponent = state.stack_pop(), state.stack_pop()
base_sol = solution(base)
if base_sol == 2:
state.stack_push(1 << exponent)
else:
try:
exponent_sol = solution(exponent)
except MultipleSolutionsError:
state.stack_push(exponent) # restore stack
state.stack_push(base)
self.add_for_fuzzing(state, exponent,
EXP_EXPONENT_FUZZ)
return False
else:
state.stack_push(
claripy.BVV(base_sol**exponent_sol, 256))
elif op == opcode_values.LT:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(bool_to_bv(claripy.ULT(s0, s1)))
elif op == opcode_values.GT:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(bool_to_bv(claripy.UGT(s0, s1)))
elif op == opcode_values.SLT:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(bool_to_bv(claripy.SLT(s0, s1)))
elif op == opcode_values.SGT:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(bool_to_bv(claripy.SGT(s0, s1)))
elif op == opcode_values.SIGNEXTEND:
# TODO: Use Claripy's SignExt that should do exactly that.
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
# s0 is the number of bits. s1 the number we want to extend.
s0 = solution(s0)
if s0 <= 31:
sign_bit = 1 << (s0 * 8 + 7)
state.stack_push(
claripy.If(
s1 & sign_bit == 0,
s1 & (sign_bit - 1),
s1 | ((1 << 256) - sign_bit),
))
else:
state.stack_push(s1)
elif op == opcode_values.EQ:
s0, s1 = state.stack_pop(), state.stack_pop()
state.stack_push(bool_to_bv(s0 == s1))
elif op == opcode_values.ISZERO:
state.stack_push(bool_to_bv(state.stack_pop() == BVV_0))
elif op == opcode_values.AND:
s0, s1 = state.stack_pop(), state.stack_pop()
state.stack_push(s0 & s1)
elif op == opcode_values.OR:
s0, s1 = state.stack_pop(), state.stack_pop()
state.stack_push(s0 | s1)
elif op == opcode_values.XOR:
s0, s1 = state.stack_pop(), state.stack_pop()
state.stack_push(s0 ^ s1)
elif op == opcode_values.NOT:
state.stack_push(~state.stack_pop())
elif op == opcode_values.BYTE:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(
s1.LShR(claripy.If(s0 > 31, 32, 31 - s0) * 8) & 0xFF)
elif op == opcode_values.PC:
state.stack_push(bvv(state.pc))
elif op == opcode_values.GAS:
state.stack_push(state.env.gas)
elif op == opcode_values.ADDRESS:
state.stack_push(state.env.address)
elif op == opcode_values.BALANCE:
addr = solution(state.stack_pop())
if addr != solution(state.env.address):
raise utils.InterpreterError(
state,
"Can only query balance of the current contract for now"
)
state.stack_push(state.env.balance)
elif op == opcode_values.ORIGIN:
state.stack_push(state.env.origin)
elif op == opcode_values.CALLER:
state.stack_push(state.env.caller)
elif op == opcode_values.CALLVALUE:
state.stack_push(state.env.value)
elif op == opcode_values.BLOCKHASH:
block_num = state.stack_pop()
if block_num not in state.env.block_hashes:
state.env.block_hashes[block_num] = claripy.BVS(
"blockhash[%s]" % block_num, 256)
state.stack_push(state.env.block_hashes[block_num])
elif op == opcode_values.TIMESTAMP:
state.stack_push(state.env.block_timestamp)
elif op == opcode_values.NUMBER:
state.stack_push(state.env.block_number)
elif op == opcode_values.COINBASE:
state.stack_push(state.env.coinbase)
elif op == opcode_values.DIFFICULTY:
state.stack_push(state.env.difficulty)
elif op == opcode_values.POP:
state.stack_pop()
elif op == opcode_values.JUMP:
addr = solution(state.stack_pop())
if addr >= len(self.code
) or self.code[addr] != opcode_values.JUMPDEST:
raise utils.CodeError("Invalid jump (%i)" % addr)
state.pc = addr
self.add_branch(state)
return False
elif op == opcode_values.JUMPI:
addr, condition = solution(
state.stack_pop()), state.stack_pop()
state_false = state.copy()
state.solver.add(condition != BVV_0)
state_false.solver.add(condition == BVV_0)
state_false.pc += 1
self.add_branch(state_false)
state.pc = addr
if (state.pc >= len(self.code)
or self.code[state.pc] != opcode_values.JUMPDEST):
raise utils.CodeError("Invalid jump (%i)" % (state.pc - 1))
self.add_branch(state)
return False
elif opcode_values.PUSH1 <= op <= opcode_values.PUSH32:
pushnum = op - opcode_values.PUSH1 + 1
raw_value = self.code.read(pushnum)
state.pc += pushnum
state.stack_push(
bvv(int.from_bytes(raw_value, byteorder="big")))
elif opcode_values.DUP1 <= op <= opcode_values.DUP16:
depth = op - opcode_values.DUP1 + 1
state.stack_push(state.stack[-depth])
elif opcode_values.SWAP1 <= op <= opcode_values.SWAP16:
depth = op - opcode_values.SWAP1 + 1
temp = state.stack[-depth - 1]
state.stack[-depth - 1] = state.stack[-1]
state.stack[-1] = temp
elif opcode_values.LOG0 <= op <= opcode_values.LOG4:
depth = op - opcode_values.LOG0
mstart, msz = (state.stack_pop(), state.stack_pop())
topics = [state.stack_pop() for x in range(depth)]
elif op == opcode_values.SHA3:
start, length = solution(state.stack_pop()), solution(
state.stack_pop())
memory = state.memory.read(start, length)
state.stack_push(Sha3(memory))
elif op == opcode_values.STOP:
return True
elif op == opcode_values.RETURN:
return True
elif op == opcode_values.CALLDATALOAD:
index = state.stack_pop()
try:
index_sol = solution(index)
except MultipleSolutionsError:
state.stack_push(index) # restore the stack
self.add_for_fuzzing(state, index, CALLDATALOAD_INDEX_FUZZ)
return False
state.stack_push(state.env.calldata.read(index_sol, 32))
elif op == opcode_values.CALLDATASIZE:
state.stack_push(state.env.calldata_size)
elif op == opcode_values.CALLDATACOPY:
old_state = state.copy()
mstart, dstart, size = (
state.stack_pop(),
state.stack_pop(),
state.stack_pop(),
)
mstart, dstart = solution(mstart), solution(dstart)
try:
size = solution(size)
except MultipleSolutionsError:
self.add_for_fuzzing(old_state, size,
CALLDATACOPY_SIZE_FUZZ)
return False
state.memory.copy_from(state.env.calldata, mstart, dstart,
size)
elif op == opcode_values.CODESIZE:
state.stack_push(bvv(len(self.code)))
elif op == opcode_values.EXTCODESIZE:
addr = state.stack_pop()
if (addr == state.env.address).is_true():
state.stack_push(bvv(len(self.code)))
else:
# TODO: Improve that... It's clearly not constraining enough.
state.stack_push(claripy.BVS("EXTCODESIZE[%s]" % addr,
256))
elif op == opcode_values.EXTCODECOPY:
old_state = state.copy()
addr = state.stack_pop()
mem_start = solution(state.stack_pop())
code_start = solution(state.stack_pop())
size = state.stack_pop()
try:
size = solution(size)
except MultipleSolutionsError:
# TODO: Fuzz.
# self.add_for_fuzzing(old_state, size, [])
# return False
raise
state.memory.write(
mem_start,
size,
claripy.BVS("EXTCODE[%s from %s]" % (addr, code_start),
size * 8),
)
elif op == opcode_values.CODECOPY:
mem_start, code_start, size = [
solution(state.stack_pop()) for _ in range(3)
]
for i in range(size):
if code_start + i < len(state.env.code):
state.memory.write(
mem_start + i,
1,
claripy.BVV(state.env.code[code_start + i], 8),
)
else:
state.memory.write(mem_start + i, 1, claripy.BVV(0, 8))
elif op == opcode_values.MLOAD:
index = solution(state.stack_pop())
state.stack_push(state.memory.read(index, 32))
elif op == opcode_values.MSTORE:
index, value = solution(state.stack_pop()), state.stack_pop()
state.memory.write(index, 32, value)
elif op == opcode_values.MSTORE8:
index, value = solution(state.stack_pop()), state.stack_pop()
state.memory.write(index, 1, value[7:0])
elif op == opcode_values.MSIZE:
state.stack_push(bvv(state.memory.size()))
elif op == opcode_values.SLOAD:
state.pc += 1
key = state.stack_pop()
for w_key, w_value in state.storage_written.items():
read_written = [w_key == key]
if state.solver.satisfiable(
extra_constraints=read_written):
new_state = state.copy()
new_state.solver.add(read_written)
new_state.stack_push(w_value)
self.add_branch(new_state)
state.solver.add(w_key != key)
if state.solver.satisfiable():
assert key not in state.storage_written
if key not in state.storage_read:
state.storage_read[key] = claripy.BVS(
"storage[%s]" % key, 256)
state.stack_push(state.storage_read[key])
self.add_branch(state)
return
elif op == opcode_values.SSTORE:
state.pc += 1
key = state.stack_pop()
value = state.stack_pop()
for w_key, w_value in state.storage_written.items():
read_written = [w_key == key]
if state.solver.satisfiable(
extra_constraints=read_written):
new_state = state.copy()
new_state.solver.add(read_written)
new_state.storage_written[w_key] = value
self.add_branch(new_state)
state.solver.add(w_key != key)
if state.solver.satisfiable():
assert key not in state.storage_written
state.storage_written[key] = value
self.add_branch(state)
return
elif op == opcode_values.CALL:
state.pc += 1
# pylint:disable=unused-variable
gas, to_, value, meminstart, meminsz, memoutstart, memoutsz = (
state.stack_pop() for _ in range(7))
# First possibility: the call fails
# (always possible with a call stack big enough)
state_fail = state.copy()
state_fail.stack_push(BVV_0)
self.add_branch(state_fail)
# Second possibility: success.
state.calls.append((memoutsz, memoutstart, meminsz, meminstart,
value, to_, gas))
memoutsz = solution(memoutsz)
if memoutsz != 0:
# If we expect some output, let's constraint the call to
# be to a contract that we do control. Otherwise it could
# return anything...
state.solver.add(to_[159:0] == utils.DEFAULT_CALLER[159:0])
memoutstart = solution(memoutstart)
state.memory.write(
memoutstart,
memoutsz,
claripy.BVS("CALL_RETURN[%s]" % to_, memoutsz * 8),
)
state.stack_push(BVV_1)
self.add_branch(state)
return False
elif op == opcode_values.DELEGATECALL:
state.pc += 1
# pylint:disable=unused-variable
gas, to_, meminstart, meminsz, memoutstart, memoutsz = (
state.stack_pop() for _ in range(6))
# First possibility: the call fails
# (always possible with a call stack big enough)
state_fail = state.copy()
state_fail.stack_push(BVV_0)
self.add_branch(state_fail)
# If the call is to a specific contract we don't control,
# don't assume it could return anything, or even be successful.
# So we say we need to be able to call an arbitrary contract.
state.solver.add(to_[159:0] == utils.DEFAULT_CALLER[159:0])
# Second possibility: success.
state.calls.append(
(memoutsz, memoutstart, meminsz, meminstart, to_, gas))
memoutsz = solution(memoutsz)
if memoutsz != 0:
memoutstart = solution(memoutstart)
state.memory.write(
memoutstart,
memoutsz,
claripy.BVS("DELEGATECALL_RETURN[%s]" % to_,
memoutsz * 8),
)
state.stack_push(BVV_1)
self.add_branch(state)
return False
elif op == opcode_values.RETURNDATASIZE:
state.stack_push(claripy.BVS("RETURNDATASIZE", 256))
elif op == opcode_values.RETURNDATACOPY:
old_state = state.copy()
mem_start_position = solution(state.stack_pop())
returndata_start_position = solution(state.stack_pop())
size = state.stack_pop()
try:
size = solution(size)
except MultipleSolutionsError:
self.add_for_fuzzing(old_state, size,
RETURNDATACOPY_SIZE_FUZZ)
return False
state.memory.write(mem_start_position, size,
claripy.BVS("RETURNDATACOPY", size * 8))
elif op == opcode_values.SELFDESTRUCT:
state.selfdestruct_to = state.stack[-1]
return True
elif op == opcode_values.REVERT:
return False
else:
raise utils.InterpreterError(state, "Unknown opcode %#x" % op)
state.pc += 1
def exec_branch(self, state): # pylint:disable=invalid-name
"""Execute forward from a state, queuing new states if needed."""
logger.debug("Constraints: %s", state.solver.constraints)
def solution(variable):
"""Returns the solution. There must be one or we fail."""
solutions = state.solver.eval(variable, 2)
if len(solutions) > 1:
raise ValueError("Ambiguous solution for %s (%s)" %
(variable, self.code[state.pc]))
solution = solutions[0]
return solution if isinstance(solution,
numbers.Number) else solution.value
state.score += 1
self.code.pc = state.pc
while True:
if state.pc >= len(self.code):
return True
op = self.code.next()
self.coverage[state.pc] += 1
logger.debug("NEW STEP")
logger.debug("Memory: %s", state.memory)
logger.debug("Stack: %s", state.stack)
logger.debug("PC: %i, %s", state.pc, op)
assert self.code.pc == state.pc + 1
assert isinstance(op, numbers.Number)
assert all(
hasattr(i, "symbolic") for i in
state.stack), "The stack musty only contains claripy BV's"
# Trivial operations first
if not self.code.is_valid_opcode(state.pc):
raise utils.CodeError("Trying to execute PUSH data")
elif op == 254: # INVALID opcode
raise utils.CodeError("designed INVALID opcode")
elif op == opcode_values.JUMPDEST:
pass
elif op == opcode_values.ADD:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(s0 + s1)
elif op == opcode_values.SUB:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(s0 - s1)
elif op == opcode_values.MUL:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(s0 * s1)
elif op == opcode_values.DIV:
# We need to use claripy.LShR instead of a division if possible,
# because the solver is bad dealing with divisions, better
# with shifts. And we need shifts to handle the solidity ABI
# for function selection.
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1) # pylint:disable=invalid-name
except ValueError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0 / s1))
else:
if s1 == 0:
state.stack_push(BVV_0)
elif s1 == 1:
state.stack_push(s0)
elif s1 & (s1 - 1) == 0:
exp = int(math.log(s1, 2))
state.stack_push(s0.LShR(exp))
else:
state.stack_push(s0 / s1)
elif op == opcode_values.SDIV:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1)
except ValueError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0.SDiv(s1)))
else:
state.stack_push(BVV_0 if s1 == 0 else s0.SDiv(s1))
elif op == opcode_values.MOD:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1)
except ValueError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0 % s1))
else:
state.stack_push(BVV_0 if s1 == 0 else s0 % s1)
elif op == opcode_values.SMOD:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
try:
s1 = solution(s1)
except ValueError:
state.stack_push(claripy.If(s1 == 0, BVV_0, s0.SMod(s1)))
else:
state.stack_push(BVV_0 if s1 == 0 else s0.SMod(s1))
elif op == opcode_values.ADDMOD:
s0, s1, s2 = state.stack_pop(), state.stack_pop(
), state.stack_pop()
try:
s2 = solution(s2)
except ValueError:
state.stack_push(claripy.If(s2 == 0, BVV_0,
(s0 + s1) % s2))
else:
state.stack_push(BVV_0 if s2 == 0 else (s0 + s1) % s2)
elif op == opcode_values.MULMOD:
s0, s1, s2 = state.stack_pop(), state.stack_pop(
), state.stack_pop()
try:
s2 = solution(s2)
except ValueError:
state.stack_push(claripy.If(s2 == 0, BVV_0,
(s0 * s1) % s2))
else:
state.stack_push(BVV_0 if s2 == 0 else (s0 * s1) % s2)
elif op == opcode_values.EXP:
base, exponent = solution(state.stack_pop()), state.stack_pop()
if base == 2:
state.stack_push(1 << exponent)
else:
exponent = solution(exponent)
state.stack_push(claripy.BVV(base**exponent, 256))
elif op == opcode_values.LT:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(claripy.ULT(s0, s1))
elif op == opcode_values.GT:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(claripy.UGT(s0, s1))
elif op == opcode_values.SLT:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(claripy.SLT(s0, s1))
elif op == opcode_values.SGT:
s0, s1 = (
not_bool(state.stack_pop()),
not_bool(state.stack_pop()),
) # pylint:disable=invalid-name
state.stack_push(claripy.SGT(s0, s1))
elif op == opcode_values.SIGNEXTEND:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
# s0 is the number of bits. s1 the number we want to extend.
s0 = solution(s0)
if s0 <= 31:
sign_bit = 1 << (s0 * 8 + 7)
state.stack_push(
claripy.If(
s1 & sign_bit == 0,
s1 & (sign_bit - 1),
s1 | ((1 << 256) - sign_bit),
))
else:
state.stack_push(s1)
elif op == opcode_values.EQ:
s0, s1 = state.stack_pop(), state.stack_pop()
if isinstance(s0, claripy.ast.Bool) and isinstance(
s1, claripy.ast.Bool):
state.stack_push(s0 == s1)
else:
state.stack_push(not_bool(s0) == not_bool(s1))
elif op == opcode_values.ISZERO:
condition = state.stack_pop()
if isinstance(condition, claripy.ast.Bool):
state.stack_push(claripy.Not(condition))
else:
state.stack_push(condition == BVV_0)
elif op == opcode_values.AND:
s0, s1 = make_consistent(state.stack_pop(), state.stack_pop())
if isinstance(s0, claripy.ast.Bool) and isinstance(
s1, claripy.ast.Bool):
state.stack_push(s0 and s1)
else:
state.stack_push(s0 & s1)
elif op == opcode_values.OR:
s0, s1 = make_consistent(state.stack_pop(), state.stack_pop())
if isinstance(s0, claripy.ast.Bool) and isinstance(
s1, claripy.ast.Bool):
state.stack_push(s0 or s1)
else:
state.stack_push(s0 | s1)
elif op == opcode_values.XOR:
s0, s1 = make_consistent(state.stack_pop(), state.stack_pop())
state.stack_push(s0 ^ s1)
elif op == opcode_values.NOT:
state.stack_push(~state.stack_pop())
elif op == opcode_values.BYTE:
s0, s1 = (
state.stack_pop(),
state.stack_pop(),
) # pylint:disable=invalid-name
state.stack_push(
s1.LShR(claripy.If(s0 > 31, 32, 31 - s0) * 8) & 0xFF)
elif op == opcode_values.PC:
state.stack_push(bvv(state.pc))
elif op == opcode_values.GAS:
state.stack_push(state.env.gas)
elif op == opcode_values.ADDRESS:
state.stack_push(state.env.address)
elif op == opcode_values.BALANCE:
addr = solution(state.stack_pop())
if addr != solution(state.env.address):
raise utils.InterpreterError(
state,
"Can only query balance of the current contract for now"
)
state.stack_push(state.env.balance)
elif op == opcode_values.ORIGIN:
state.stack_push(state.env.origin)
elif op == opcode_values.CALLER:
state.stack_push(state.env.caller)
elif op == opcode_values.CALLVALUE:
state.stack_push(state.env.value)
elif op == opcode_values.BLOCKHASH:
block_num = state.stack_pop()
if block_num not in state.env.block_hashes:
state.env.block_hashes[block_num] = claripy.BVS(
"blockhash[%s]" % block_num, 256)
state.stack_push(state.env.block_hashes[block_num])
elif op == opcode_values.TIMESTAMP:
state.stack_push(state.env.block_timestamp)
elif op == opcode_values.NUMBER:
state.stack_push(state.env.block_number)
elif op == opcode_values.COINBASE:
state.stack_push(state.env.coinbase)
elif op == opcode_values.DIFFICULTY:
state.stack_push(state.env.difficulty)
elif op == opcode_values.POP:
state.stack_pop()
elif op == opcode_values.JUMP:
addr = solution(state.stack_pop())
if addr >= len(self.code
) or self.code[addr] != opcode_values.JUMPDEST:
raise utils.CodeError("Invalid jump (%i)" % addr)
state.pc = addr
self.add_branch(state)
return False
elif op == opcode_values.JUMPI:
addr, condition = solution(
state.stack_pop()), state.stack_pop()
state_false = state.copy()
if isinstance(condition, claripy.ast.Bool):
state.solver.add(condition)
state_false.solver.add(claripy.Not(condition))
else:
state.solver.add(condition != 0)
state_false.solver.add(condition == 0)
state_false.pc += 1
self.add_branch(state_false)
state.pc = addr
if (state.pc >= len(self.code)
or self.code[state.pc] != opcode_values.JUMPDEST):
raise utils.CodeError("Invalid jump (%i)" % (state.pc - 1))
self.add_branch(state)
return False
elif opcode_values.PUSH1 <= op <= opcode_values.PUSH32:
pushnum = op - opcode_values.PUSH1 + 1
raw_value = self.code.read(pushnum)
state.pc += pushnum
state.stack_push(
bvv(int.from_bytes(raw_value, byteorder="big")))
elif opcode_values.DUP1 <= op <= opcode_values.DUP16:
depth = op - opcode_values.DUP1 + 1
state.stack_push(state.stack[-depth])
elif opcode_values.SWAP1 <= op <= opcode_values.SWAP16:
depth = op - opcode_values.SWAP1 + 1
temp = state.stack[-depth - 1]
state.stack[-depth - 1] = state.stack[-1]
state.stack[-1] = temp
elif opcode_values.LOG0 <= op <= opcode_values.LOG4:
depth = op - opcode_values.LOG0
mstart, msz = (state.stack_pop(), state.stack_pop())
topics = [state.stack_pop() for x in range(depth)]
elif op == opcode_values.SHA3:
start, length = solution(state.stack_pop()), solution(
state.stack_pop())
memory = state.memory.read(start, length)
state.stack_push(Sha3(memory))
elif op == opcode_values.STOP:
return True
elif op == opcode_values.RETURN:
return True
elif op == opcode_values.CALLDATALOAD:
indexes = state.stack_pop()
try:
index = solution(indexes)
except ValueError: # Multiple solutions, let's fuzz.
state.stack_push(indexes) # restore the stack
self.add_for_fuzzing(state, indexes, CALLDATASIZE_FUZZ)
return False
state.solver.add(state.env.calldata_size >= index + 32)
state.stack_push(state.env.calldata.read(index, 32))
elif op == opcode_values.CALLDATASIZE:
state.stack_push(state.env.calldata_size)
elif op == opcode_values.CALLDATACOPY:
old_state = state.copy()
mstart, dstart, size = (
state.stack_pop(),
state.stack_pop(),
state.stack_pop(),
)
mstart, dstart = solution(mstart), solution(dstart)
try:
size = solution(size)
except ValueError:
self.add_for_fuzzing(old_state, size, CALLDATASIZE_FUZZ)
return False
state.memory.copy_from(state.env.calldata, mstart, dstart,
size)
state.solver.add(state.env.calldata_size >= dstart + size)
elif op == opcode_values.CODESIZE:
state.stack_push(bvv(len(self.code)))
elif op == opcode_values.EXTCODESIZE:
addr = state.stack_pop()
if (addr == state.env.address).is_true():
state.stack_push(bvv(len(self.code)))
else:
# TODO: Improve that... It's clearly not constraining enough.
state.stack_push(claripy.BVS("EXTCODESIZE[%s]" % addr,
256))
elif op == opcode_values.CODECOPY:
mem_start, code_start, size = [
solution(state.stack_pop()) for _ in range(3)
]
for i in range(size):
if code_start + i < len(state.env.code):
state.memory.write(
mem_start + i,
1,
claripy.BVV(state.env.code[code_start + i], 8),
)
else:
state.memory.write(mem_start + i, 1, claripy.BVV(0, 8))
elif op == opcode_values.MLOAD:
index = solution(state.stack_pop())
state.stack_push(state.memory.read(index, 32))
elif op == opcode_values.MSTORE:
index, value = solution(state.stack_pop()), not_bool(
state.stack_pop())
state.memory.write(index, 32, value)
elif op == opcode_values.MSTORE8:
index, value = solution(state.stack_pop()), not_bool(
state.stack_pop())
state.memory.write(index, 1, value[7:0])
elif op == opcode_values.MSIZE:
state.stack_push(bvv(state.memory.size()))
elif op == opcode_values.SLOAD:
# TODO: This is inaccurate, because the storage can change
# in a single transaction.
# See commit d98cab834f8f359f01ef805256d179f5529ebe30.
key = state.stack_pop()
if key in state.storage_written:
state.stack_push(state.storage_written[key])
else:
if key not in state.storage_read:
state.storage_read[key] = claripy.BVS(
"storage[%s]" % key, 256)
state.stack_push(state.storage_read[key])
elif op == opcode_values.SSTORE:
# TODO: This is inaccurate, because the storage can change
# in a single transaction.
# See commit d98cab834f8f359f01ef805256d179f5529ebe30.
key = state.stack_pop()
value = state.stack_pop()
state.storage_written[key] = value
elif op == opcode_values.CALL:
state.pc += 1
# First possibility: the call fails
# (always possible with a call stack big enough)
state_fail = state.copy()
state_fail.stack_push(claripy.BoolV(False))
self.add_branch(state_fail)
# Second possibility: success.
state.calls.append(state.stack[-7:])
# pylint:disable=unused-variable
gas, to_, value, meminstart, meminsz, memoutstart, memoutsz = (
state.stack_pop() for _ in range(7))
if solution(memoutsz) != 0:
raise utils.InterpreterError(state,
"CALL seems to return data")
if solution(meminsz) != 0:
raise utils.InterpreterError(state,
"CALL seems to take data")
state.stack_push(claripy.BoolV(True))
self.add_branch(state)
return False
elif op == opcode_values.SELFDESTRUCT:
state.selfdestruct_to = state.stack[-1]
return True
elif op == opcode_values.REVERT:
return False
else:
raise utils.InterpreterError(state, "Unknown opcode %s" % op)
state.pc += 1