mirror of https://github.com/ConsenSys/mythril
JoranHonig
5 years ago
committed by
GitHub
commit
5faac03012
@ -1,30 +0,0 @@ |
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from mythril.support.support_utils import Singleton |
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class AnalysisArgs(object, metaclass=Singleton): |
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""" |
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This module helps in preventing args being sent through multiple of classes to reach analysis modules |
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""" |
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def __init__(self): |
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self._loop_bound = 3 |
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self._solver_timeout = 10000 |
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def set_loop_bound(self, loop_bound: int): |
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if loop_bound is not None: |
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self._loop_bound = loop_bound |
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def set_solver_timeout(self, solver_timeout: int): |
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if solver_timeout is not None: |
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self._solver_timeout = solver_timeout |
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@property |
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def loop_bound(self): |
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return self._loop_bound |
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@property |
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def solver_timeout(self): |
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return self._solver_timeout |
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analysis_args = AnalysisArgs() |
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@ -0,0 +1,112 @@ |
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"""This module contains the detection code for predictable variable |
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dependence.""" |
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import logging |
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from copy import copy |
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from mythril.analysis.module.base import DetectionModule, EntryPoint |
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from mythril.analysis.report import Issue |
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from mythril.exceptions import UnsatError |
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from mythril.analysis import solver |
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from mythril.analysis.swc_data import TX_ORIGIN_USAGE |
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from mythril.laser.ethereum.state.global_state import GlobalState |
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from typing import List |
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log = logging.getLogger(__name__) |
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class TxOriginAnnotation: |
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"""Symbol annotation added to a variable that is initialized with a call to the ORIGIN instruction.""" |
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def __init__(self) -> None: |
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pass |
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class TxOrigin(DetectionModule): |
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"""This module detects whether control flow decisions are made based on the transaction origin.""" |
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name = "Control flow depends on tx.origin" |
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swc_id = TX_ORIGIN_USAGE |
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description = "Check whether control flow decisions are influenced by tx.origin" |
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entry_point = EntryPoint.CALLBACK |
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pre_hooks = ["JUMPI"] |
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post_hooks = ["ORIGIN"] |
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def _execute(self, state: GlobalState) -> None: |
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""" |
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:param state: |
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:return: |
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""" |
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if state.get_current_instruction()["address"] in self.cache: |
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return |
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issues = self._analyze_state(state) |
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for issue in issues: |
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self.cache.add(issue.address) |
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self.issues.extend(issues) |
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@staticmethod |
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def _analyze_state(state: GlobalState) -> list: |
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""" |
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:param state: |
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:return: |
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""" |
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issues = [] |
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if state.get_current_instruction()["opcode"] == "JUMPI": |
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# We're in JUMPI prehook |
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for annotation in state.mstate.stack[-2].annotations: |
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if isinstance(annotation, TxOriginAnnotation): |
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constraints = copy(state.world_state.constraints) |
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try: |
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transaction_sequence = solver.get_transaction_sequence( |
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state, constraints |
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) |
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except UnsatError: |
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continue |
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description = ( |
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"The tx.origin environment variable has been found to influence a control flow decision. " |
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"Note that using tx.origin as a security control might cause a situation where a user " |
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"inadvertently authorizes a smart contract to perform an action on their behalf. It is " |
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"recommended to use msg.sender instead." |
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) |
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severity = "Low" |
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""" |
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Note: We report the location of the JUMPI instruction. Usually this maps to an if or |
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require statement. |
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""" |
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issue = Issue( |
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contract=state.environment.active_account.contract_name, |
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function_name=state.environment.active_function_name, |
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address=state.get_current_instruction()["address"], |
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swc_id=TX_ORIGIN_USAGE, |
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bytecode=state.environment.code.bytecode, |
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title="Dependence on tx.origin", |
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severity=severity, |
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description_head="Use of tx.origin as a part of authorization control.", |
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description_tail=description, |
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gas_used=(state.mstate.min_gas_used, state.mstate.max_gas_used), |
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transaction_sequence=transaction_sequence, |
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) |
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issues.append(issue) |
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else: |
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# In ORIGIN posthook |
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state.mstate.stack[-1].annotate(TxOriginAnnotation()) |
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return issues |
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detector = TxOrigin() |
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@ -1,85 +0,0 @@ |
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"""This module contains the detection code for deprecated op codes.""" |
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from mythril.analysis.report import Issue |
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from mythril.analysis.swc_data import DEPRECATED_FUNCTIONS_USAGE |
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from mythril.analysis.module.base import DetectionModule, EntryPoint |
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from mythril.laser.ethereum.state.global_state import GlobalState |
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import logging |
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log = logging.getLogger(__name__) |
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DESCRIPTION = """ |
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Check for usage of deprecated opcodes |
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""" |
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class DeprecatedOperations(DetectionModule): |
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"""This module checks for the usage of deprecated op codes.""" |
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name = "Usage of deprecated instructions" |
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swc_id = DEPRECATED_FUNCTIONS_USAGE |
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description = DESCRIPTION |
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entry_point = EntryPoint.CALLBACK |
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pre_hooks = ["ORIGIN", "CALLCODE"] |
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def _execute(self, state: GlobalState) -> None: |
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""" |
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:param state: |
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:return: |
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""" |
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if state.get_current_instruction()["address"] in self.cache: |
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return |
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issues = self._analyze_state(state) |
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self.issues.extend(issues) |
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def _analyze_state(self, state): |
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""" |
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:param state: |
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:return: |
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""" |
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node = state.node |
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instruction = state.get_current_instruction() |
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if instruction["opcode"] == "ORIGIN": |
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log.debug("ORIGIN in function " + node.function_name) |
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title = "Use of tx.origin" |
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description_head = "Use of tx.origin is deprecated." |
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description_tail = ( |
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"The smart contract retrieves the transaction origin (tx.origin) using msg.origin. " |
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"Use of msg.origin is deprecated and the instruction may be removed in the future. " |
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"Use msg.sender instead.\nSee also: " |
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"https://solidity.readthedocs.io/en/develop/security-considerations.html#tx-origin" |
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) |
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swc_id = DEPRECATED_FUNCTIONS_USAGE |
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elif instruction["opcode"] == "CALLCODE": |
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log.debug("CALLCODE in function " + state.environment.active_function_name) |
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title = "Use of callcode" |
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description_head = "Use of callcode is deprecated." |
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description_tail = ( |
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"The callcode method executes code of another contract in the context of the caller account. " |
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"Due to a bug in the implementation it does not persist sender and value over the call. It was " |
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"therefore deprecated and may be removed in the future. Use the delegatecall method instead." |
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) |
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swc_id = DEPRECATED_FUNCTIONS_USAGE |
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else: |
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return [] |
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issue = Issue( |
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contract=state.environment.active_account.contract_name, |
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function_name=state.environment.active_function_name, |
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address=instruction["address"], |
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title=title, |
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bytecode=state.environment.code.bytecode, |
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swc_id=swc_id, |
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severity="Medium", |
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description_head=description_head, |
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description_tail=description_tail, |
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) |
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return [issue] |
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detector = DeprecatedOperations() |
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@ -0,0 +1,49 @@ |
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from functools import lru_cache |
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from z3 import sat, unknown |
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from mythril.support.support_args import args |
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from mythril.laser.smt import Optimize |
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from mythril.laser.ethereum.time_handler import time_handler |
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from mythril.exceptions import UnsatError |
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import logging |
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log = logging.getLogger(__name__) |
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# LRU cache works great when used in powers of 2 |
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@lru_cache(maxsize=2 ** 23) |
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def get_model(constraints, minimize=(), maximize=(), enforce_execution_time=True): |
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""" |
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Returns a model based on given constraints as a tuple |
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:param constraints: Tuple of constraints |
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:param minimize: Tuple of minimization conditions |
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:param maximize: Tuple of maximization conditions |
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:param enforce_execution_time: Bool variable which enforces --execution-timeout's time |
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:return: |
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""" |
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s = Optimize() |
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timeout = args.solver_timeout |
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if enforce_execution_time: |
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timeout = min(timeout, time_handler.time_remaining() - 500) |
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if timeout <= 0: |
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raise UnsatError |
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s.set_timeout(timeout) |
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for constraint in constraints: |
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if type(constraint) == bool and not constraint: |
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raise UnsatError |
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constraints = [constraint for constraint in constraints if type(constraint) != bool] |
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for constraint in constraints: |
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s.add(constraint) |
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for e in minimize: |
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s.minimize(e) |
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for e in maximize: |
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s.maximize(e) |
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result = s.check() |
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if result == sat: |
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return s.model() |
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elif result == unknown: |
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log.debug("Timeout encountered while solving expression using z3") |
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raise UnsatError |
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@ -0,0 +1,12 @@ |
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class Args: |
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""" |
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This module helps in preventing args being sent through multiple of classes to reach |
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any analysis/laser module |
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""" |
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def __init__(self): |
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self.solver_timeout = 10000 |
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self.sparse_pruning = True |
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args = Args() |
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