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Revise laser to work using keccak store

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pull/501/head
Joran Honig 6 years ago
parent 90f5622939
commit bac076098c
2 changed files with 105 additions and 21 deletions
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  1. 122
      mythril/laser/ethereum/instructions.py
  2. 4
      mythril/laser/ethereum/svm.py

122
mythril/laser/ethereum/instructions.py
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@ -2,22 +2,24 @@ import binascii
import logging
from copy import copy, deepcopy
import ethereum.opcodes as opcodes
from ethereum import utils
from z3 import Extract, UDiv, simplify, Concat, ULT, UGT, BitVecNumRef, Not, \
is_false, is_expr, ExprRef, URem, SRem
from z3 import BitVecVal, If, BoolRef
is_false, is_expr, ExprRef, URem, SRem, BitVec, Solver, is_true, BitVecVal, If, BoolRef, Or
import mythril.laser.ethereum.util as helper
from mythril.laser.ethereum import util
from mythril.laser.ethereum.call import get_call_parameters
from mythril.laser.ethereum.state import GlobalState, MachineState, Environment, CalldataType
from mythril.laser.ethereum.state import GlobalState, CalldataType
import mythril.laser.ethereum.natives as natives
from mythril.laser.ethereum.transaction import MessageCallTransaction, TransactionEndSignal, TransactionStartSignal, ContractCreationTransaction
from mythril.laser.ethereum.transaction import MessageCallTransaction, TransactionStartSignal, ContractCreationTransaction
from mythril.laser.ethereum.keccak import KeccakFunctionManager
TT256 = 2 ** 256
TT256M1 = 2 ** 256 - 1
keccak_function_manager: KeccakFunctionManager = KeccakFunctionManager()
class StackUnderflowException(Exception):
pass
@ -341,12 +343,12 @@ class Instruction:
except AttributeError:
logging.debug("CALLDATALOAD: Unsupported symbolic index")
state.stack.append(global_state.new_bitvec(
"calldata_" + str(environment.active_account.contract_name) + str(len(global_state.current_transaction.caller)) +"[" + str(simplify(op0)) + "]", 256))
"calldata_" + str(environment.active_account.contract_name) + "[" + str(simplify(op0)) + "]", 256))
return [global_state]
except IndexError:
logging.debug("Calldata not set, using symbolic variable instead")
state.stack.append(global_state.new_bitvec(
"calldata_" + str(environment.active_account.contract_name) +str(global_state.current_transaction.caller)+ "[" + str(simplify(op0)) + "]", 256))
"calldata_" + str(environment.active_account.contract_name) + "[" + str(simplify(op0)) + "]", 256))
return [global_state]
if type(b) == int:
@ -482,6 +484,8 @@ class Instruction:
@instruction
def sha3_(self, global_state):
global keccak_function_manager
state = global_state.mstate
environment = global_state.environment
op0, op1 = state.stack.pop(), state.stack.pop()
@ -493,7 +497,7 @@ class Instruction:
# Can't access symbolic memory offsets
if is_expr(op0):
op0 = simplify(op0)
state.stack.append(global_state.new_bitvec("KECCAC_mem[" + str(op0) + "]", 256))
state.stack.append(BitVec("KECCAC_mem[" + str(op0) + "]", 256))
return [global_state]
try:
@ -504,18 +508,17 @@ class Instruction:
i += 1
# FIXME: broad exception catch
except:
argument = str(state.memory[index]).replace(" ", "_")
svar = str(state.memory[index])
svar = svar.replace(" ", "_")
state.stack.append(global_state.new_bitvec("keccac_" + svar, 256))
result = BitVec("KECCAC[{}]".format(argument), 256)
keccak_function_manager.add_keccak(result, state.memory[index])
state.stack.append(result)
return [global_state]
keccac = utils.sha3(utils.bytearray_to_bytestr(data))
logging.debug("Computed SHA3 Hash: " + str(binascii.hexlify(keccac)))
keccak = utils.sha3(utils.bytearray_to_bytestr(data))
logging.debug("Computed SHA3 Hash: " + str(binascii.hexlify(keccak)))
state.stack.append(BitVecVal(util.concrete_int_from_bytes(keccac, 0), 256))
state.stack.append(BitVecVal(util.concrete_int_from_bytes(keccak, 0), 256))
return [global_state]
@instruction
@ -727,26 +730,68 @@ class Instruction:
@instruction
def sload_(self, global_state):
global keccak_function_manager
state = global_state.mstate
index = state.stack.pop()
logging.debug("Storage access at index " + str(index))
try:
index = util.get_concrete_int(index)
except AttributeError:
index = str(index)
return self._sload_helper(global_state, index)
except AttributeError:
if not keccak_function_manager.is_keccak(index):
return self._sload_helper(global_state, str(index))
storage_keys = global_state.environment.active_account.storage.keys()
keccak_keys = list(filter(keccak_function_manager.is_keccak, storage_keys))
results = []
constraints = []
for keccak_key in keccak_keys:
key_argument = keccak_function_manager.get_argument(keccak_key)
index_argument = keccak_function_manager.get_argument(index)
constraints.append((keccak_key, key_argument == index_argument))
for (keccak_key, constraint) in constraints:
if constraint in state.constraints:
results += self._sload_helper(global_state, keccak_key, [constraint])
if len(results) > 0:
return results
for (keccak_key, constraint) in constraints:
results += self._sload_helper(copy(global_state), keccak_key, [constraint])
if len(results) > 0:
return results
return self._sload_helper(global_state, str(index))
def _sload_helper(self, global_state, index, constraints=None):
try:
data = global_state.environment.active_account.storage[index]
except KeyError:
data = global_state.new_bitvec("storage_" + str(index), 256)
global_state.environment.active_account.storage[index] = data
state.stack.append(data)
if constraints is not None:
global_state.mstate.constraints += constraints
global_state.mstate.stack.append(data)
return [global_state]
def _get_constraints(self, keccak_keys, this_key, argument):
global keccak_function_manager
for keccak_key in keccak_keys:
if keccak_key == this_key:
continue
keccak_argument = keccak_function_manager.get_argument(keccak_key)
yield keccak_argument != argument
@instruction
def sstore_(self, global_state):
global keccak_function_manager
state = global_state.mstate
index, value = state.stack.pop(), state.stack.pop()
@ -754,17 +799,52 @@ class Instruction:
try:
index = util.get_concrete_int(index)
return self._sstore_helper(global_state, index, value)
except AttributeError:
index = str(index)
is_keccak = keccak_function_manager.is_keccak(index)
if not is_keccak:
return self._sstore_helper(global_state, str(index), value)
storage_keys = global_state.environment.active_account.storage.keys()
keccak_keys = filter(keccak_function_manager.is_keccak, storage_keys)
solver = Solver()
solver.set(timeout=1000)
results = []
new = False
for keccak_key in keccak_keys:
key_argument = keccak_function_manager.get_argument(keccak_key)
index_argument = keccak_function_manager.get_argument(index)
if is_true(key_argument == index_argument):
return self._sstore_helper(copy(global_state), keccak_key, value, key_argument == index_argument)
results += self._sstore_helper(copy(global_state), keccak_key, value, key_argument == index_argument)
new = Or(new, key_argument != index_argument)
if len(results) > 0:
results += self._sstore_helper(copy(global_state), str(index), value, new)
return results
return self._sstore_helper(global_state, str(index), value)
def _sstore_helper(self, global_state, index, value, constraint=None):
try:
global_state.environment.active_account = deepcopy(global_state.environment.active_account)
global_state.accounts[
global_state.environment.active_account.address] = global_state.environment.active_account
global_state.environment.active_account.storage[index] = value
global_state.environment.active_account.storage[index] =\
value if not isinstance(value, ExprRef) else simplify(value)
except KeyError:
logging.debug("Error writing to storage: Invalid index")
if constraint is not None:
global_state.mstate.constraints.append(constraint)
return [global_state]
@instruction

4
mythril/laser/ethereum/svm.py
Unescape View File

@ -185,6 +185,10 @@ class LaserEVM:
elif opcode == "JUMPI":
for state in new_states:
self._new_node_state(state, JumpType.CONDITIONAL, state.mstate.constraints[-1])
elif opcode in ("SLOAD", "SSTORE") and len(new_states) > 1:
for state in new_states:
self._new_node_state(state, JumpType.CONDITIONAL, state.mstate.constraints[-1])
elif opcode in ("CALL", 'CALLCODE', 'DELEGATECALL', 'STATICCALL'):
assert len(new_states) <= 1
for state in new_states:

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