@ -2,51 +2,37 @@
Module detecting dangerous use of block . timestamp
"""
from slither . core . declarations import Function
from slither . analyses . data_dependency . data_dependency import is_tainted , is_dependent
from slither . core . declarations . solidity_variables import ( SolidityFunction ,
SolidityVariableComposed )
from typing import List , Tuple
from slither . analyses . data_dependency . data_dependency import is_dependent
from slither . core . cfg . node import Node
from slither . core . declarations import Function , Contract
from slither . core . declarations . solidity_variables import ( SolidityVariableComposed , SolidityVariable )
from slither . detectors . abstract_detector import ( AbstractDetector ,
DetectorClassification )
from slither . slithir . operations import Binary , BinaryType
class Timestamp ( AbstractDetector ) :
"""
"""
ARGUMENT = ' timestamp '
HELP = ' Dangerous usage of `block.timestamp` '
IMPACT = DetectorClassification . LOW
CONFIDENCE = DetectorClassification . MEDIUM
WIKI = ' https://github.com/crytic/slither/wiki/Detector-Documentation#block-timestamp '
WIKI_TITLE = ' Block timestamp '
WIKI_DESCRIPTION = ' Dangerous usage of `block.timestamp`. `block.timestamp` can be manipulated by miners. '
WIKI_EXPLOIT_SCENARIO = ''' " Bob ' s contract relies on `block.timestamp` for its randomness. Eve is a miner and manipulates `block.timestamp` to exploit Bob ' s contract. '''
WIKI_RECOMMENDATION = ' Avoid relying on `block.timestamp`. '
def timestamp ( self , func ) :
"""
"""
def _timestamp ( func : Function ) - > List [ Node ] :
ret = set ( )
for node in func . nodes :
if node . contains_require_or_assert ( ) :
for var in node . variables_read :
if is_dependent ( var , SolidityVariableComposed ( ' block.timestamp ' ) , func . contract ) :
ret . add ( node )
if is_dependent ( var , SolidityVariable ( ' now ' ) , func . contract ) :
ret . add ( node )
for ir in node . irs :
if isinstance ( ir , Binary ) and BinaryType . return_bool ( ir . type ) :
for var in ir . read :
if is_dependent ( var , SolidityVariableComposed ( ' block.timestamp ' ) , func . contract ) :
ret . add ( node )
if is_dependent ( var , SolidityVariable ( ' now ' ) , func . contract ) :
ret . add ( node )
return list ( ret )
def detect_dangerous_timestamp ( self , contract ) :
def _detect_dangerous_timestamp ( contract : Contract ) - > List [ Tuple [ Function , List [ Node ] ] ] :
"""
Args :
contract ( Contract )
@ -55,18 +41,35 @@ class Timestamp(AbstractDetector):
"""
ret = [ ]
for f in [ f for f in contract . functions if f . contract_declarer == contract ] :
nodes = self . timestamp ( f )
nodes = _ timestamp( f )
if nodes :
ret . append ( ( f , nodes ) )
return ret
class Timestamp ( AbstractDetector ) :
"""
"""
ARGUMENT = ' timestamp '
HELP = ' Dangerous usage of `block.timestamp` '
IMPACT = DetectorClassification . LOW
CONFIDENCE = DetectorClassification . MEDIUM
WIKI = ' https://github.com/crytic/slither/wiki/Detector-Documentation#block-timestamp '
WIKI_TITLE = ' Block timestamp '
WIKI_DESCRIPTION = ' Dangerous usage of `block.timestamp`. `block.timestamp` can be manipulated by miners. '
WIKI_EXPLOIT_SCENARIO = ''' " Bob ' s contract relies on `block.timestamp` for its randomness. Eve is a miner and manipulates `block.timestamp` to exploit Bob ' s contract. '''
WIKI_RECOMMENDATION = ' Avoid relying on `block.timestamp`. '
def _detect ( self ) :
"""
"""
results = [ ]
for c in self . contracts :
dangerous_timestamp = self . detect_dangerous_timestamp ( c )
dangerous_timestamp = _ detect_dangerous_timestamp( c )
for ( func , nodes ) in dangerous_timestamp :
info = [ func , " uses timestamp for comparisons \n " ]