cti-python-stix2/stix2/patterns.py

440 lines
14 KiB
Python

"""Classes to aid in working with the STIX 2 patterning language.
"""
import base64
import binascii
import datetime
import re
from .utils import parse_into_datetime
def escape_quotes_and_backslashes(s):
return s.replace(u'\\', u'\\\\').replace(u"'", u"\\'")
class _Constant(object):
pass
class StringConstant(_Constant):
def __init__(self, value):
self.value = value
def __str__(self):
return "'%s'" % escape_quotes_and_backslashes(self.value)
class TimestampConstant(_Constant):
def __init__(self, value):
try:
self.value = parse_into_datetime(value)
except Exception:
raise ValueError("must be a datetime object or timestamp string.")
def __str__(self):
return "t%s" % repr(self.value)
class IntegerConstant(_Constant):
def __init__(self, value):
try:
self.value = int(value)
except Exception:
raise ValueError("must be an integer.")
def __str__(self):
return "%s" % self.value
class FloatConstant(_Constant):
def __init__(self, value):
try:
self.value = float(value)
except Exception:
raise ValueError("must be a float.")
def __str__(self):
return "%s" % self.value
class BooleanConstant(_Constant):
def __init__(self, value):
if isinstance(value, bool):
self.value = value
return
trues = ['true', 't']
falses = ['false', 'f']
try:
if value.lower() in trues:
self.value = True
return
elif value.lower() in falses:
self.value = False
return
except AttributeError:
if value == 1:
self.value = True
return
elif value == 0:
self.value = False
return
raise ValueError("must be a boolean value.")
def __str__(self):
return str(self.value).lower()
_HASH_REGEX = {
"MD5": ("^[a-fA-F0-9]{32}$", "MD5"),
"MD6": ("^[a-fA-F0-9]{32}|[a-fA-F0-9]{40}|[a-fA-F0-9]{56}|[a-fA-F0-9]{64}|[a-fA-F0-9]{96}|[a-fA-F0-9]{128}$", "MD6"),
"RIPEMD160": ("^[a-fA-F0-9]{40}$", "RIPEMD-160"),
"SHA1": ("^[a-fA-F0-9]{40}$", "SHA-1"),
"SHA224": ("^[a-fA-F0-9]{56}$", "SHA-224"),
"SHA256": ("^[a-fA-F0-9]{64}$", "SHA-256"),
"SHA384": ("^[a-fA-F0-9]{96}$", "SHA-384"),
"SHA512": ("^[a-fA-F0-9]{128}$", "SHA-512"),
"SHA3224": ("^[a-fA-F0-9]{56}$", "SHA3-224"),
"SHA3256": ("^[a-fA-F0-9]{64}$", "SHA3-256"),
"SHA3384": ("^[a-fA-F0-9]{96}$", "SHA3-384"),
"SHA3512": ("^[a-fA-F0-9]{128}$", "SHA3-512"),
"SSDEEP": ("^[a-zA-Z0-9/+:.]{1,128}$", "ssdeep"),
"WHIRLPOOL": ("^[a-fA-F0-9]{128}$", "WHIRLPOOL"),
}
class HashConstant(StringConstant):
def __init__(self, value, type):
key = type.upper().replace('-', '')
if key in _HASH_REGEX:
vocab_key = _HASH_REGEX[key][1]
if not re.match(_HASH_REGEX[key][0], value):
raise ValueError("'%s' is not a valid %s hash" % (value, vocab_key))
self.value = value
class BinaryConstant(_Constant):
def __init__(self, value):
try:
base64.b64decode(value)
self.value = value
except (binascii.Error, TypeError):
raise ValueError("must contain a base64 encoded string")
def __str__(self):
return "b'%s'" % self.value
class HexConstant(_Constant):
def __init__(self, value):
if not re.match('^([a-fA-F0-9]{2})+$', value):
raise ValueError("must contain an even number of hexadecimal characters")
self.value = value
def __str__(self):
return "h'%s'" % self.value
class ListConstant(_Constant):
def __init__(self, values):
self.value = values
def __str__(self):
return "(" + ", ".join([("%s" % make_constant(x)) for x in self.value]) + ")"
def make_constant(value):
if isinstance(value, _Constant):
return value
try:
return parse_into_datetime(value)
except ValueError:
pass
if isinstance(value, str):
return StringConstant(value)
elif isinstance(value, bool):
return BooleanConstant(value)
elif isinstance(value, int):
return IntegerConstant(value)
elif isinstance(value, float):
return FloatConstant(value)
elif isinstance(value, list):
return ListConstant(value)
else:
raise ValueError("Unable to create a constant from %s" % value)
class _ObjectPathComponent(object):
@staticmethod
def create_ObjectPathComponent(component_name):
if component_name.endswith("_ref"):
return ReferenceObjectPathComponent(component_name)
elif component_name.find("[") != -1:
parse1 = component_name.split("[")
return ListObjectPathComponent(parse1[0], parse1[1][:-1])
else:
return BasicObjectPathComponent(component_name)
class BasicObjectPathComponent(_ObjectPathComponent):
def __init__(self, property_name, is_key=False):
self.property_name = property_name
# TODO: set is_key to True if this component is a dictionary key
# self.is_key = is_key
def __str__(self):
return self.property_name
class ListObjectPathComponent(_ObjectPathComponent):
def __init__(self, property_name, index):
self.property_name = property_name
self.index = index
def __str__(self):
return "%s[%s]" % (self.property_name, self.index)
class ReferenceObjectPathComponent(_ObjectPathComponent):
def __init__(self, reference_property_name):
self.property_name = reference_property_name
def __str__(self):
return self.property_name
class ObjectPath(object):
def __init__(self, object_type_name, property_path):
self.object_type_name = object_type_name
self.property_path = [x if isinstance(x, _ObjectPathComponent) else
_ObjectPathComponent.create_ObjectPathComponent(x)
for x in property_path]
def __str__(self):
return "%s:%s" % (self.object_type_name, ".".join(["%s" % x for x in self.property_path]))
def merge(self, other):
self.property_path.extend(other.property_path)
return self
@staticmethod
def make_object_path(lhs):
path_as_parts = lhs.split(":")
return ObjectPath(path_as_parts[0], path_as_parts[1].split("."))
class _PatternExpression(object):
pass
class _ComparisonExpression(_PatternExpression):
def __init__(self, operator, lhs, rhs, negated=False):
if operator == "=" and isinstance(rhs, (ListConstant, list)):
self.operator = "IN"
else:
self.operator = operator
if isinstance(lhs, ObjectPath):
self.lhs = lhs
else:
self.lhs = ObjectPath.make_object_path(lhs)
if isinstance(rhs, _Constant):
self.rhs = rhs
else:
self.rhs = make_constant(rhs)
self.negated = negated
self.root_type = self.lhs.object_type_name
def __str__(self):
if self.negated:
return "%s NOT %s %s" % (self.lhs, self.operator, self.rhs)
else:
return "%s %s %s" % (self.lhs, self.operator, self.rhs)
class EqualityComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(EqualityComparisonExpression, self).__init__("=", lhs, rhs, negated)
class GreaterThanComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(GreaterThanComparisonExpression, self).__init__(">", lhs, rhs, negated)
class LessThanComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(LessThanComparisonExpression, self).__init__("<", lhs, rhs, negated)
class GreaterThanEqualComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(GreaterThanEqualComparisonExpression, self).__init__(">=", lhs, rhs, negated)
class LessThanEqualComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(LessThanEqualComparisonExpression, self).__init__("<=", lhs, rhs, negated)
class InComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(InComparisonExpression, self).__init__("IN", lhs, rhs, negated)
class LikeComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(LikeComparisonExpression, self).__init__("LIKE", lhs, rhs, negated)
class MatchesComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(MatchesComparisonExpression, self).__init__("MATCHES", lhs, rhs, negated)
class IsSubsetComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(IsSubsetComparisonExpression, self).__init__("ISSUBSET", lhs, rhs, negated)
class IsSupersetComparisonExpression(_ComparisonExpression):
def __init__(self, lhs, rhs, negated=False):
super(IsSupersetComparisonExpression, self).__init__("ISSUPERSET", lhs, rhs, negated)
class _BooleanExpression(_PatternExpression):
def __init__(self, operator, operands):
self.operator = operator
self.operands = []
for arg in operands:
if not hasattr(self, "root_type"):
self.root_type = arg.root_type
elif self.root_type and (self.root_type != arg.root_type) and operator == "AND":
raise ValueError("All operands to an 'AND' expression must have the same object type")
elif self.root_type and (self.root_type != arg.root_type):
self.root_type = None
self.operands.append(arg)
def __str__(self):
sub_exprs = []
for o in self.operands:
sub_exprs.append("%s" % o)
return (" " + self.operator + " ").join(sub_exprs)
class AndBooleanExpression(_BooleanExpression):
def __init__(self, operands):
super(AndBooleanExpression, self).__init__("AND", operands)
class OrBooleanExpression(_BooleanExpression):
def __init__(self, operands):
super(OrBooleanExpression, self).__init__("OR", operands)
class ObservationExpression(_PatternExpression):
def __init__(self, operand):
self.operand = operand
def __str__(self):
return "[%s]" % self.operand
class _CompoundObservationExpression(_PatternExpression):
def __init__(self, operator, operands):
self.operator = operator
self.operands = operands
def __str__(self):
sub_exprs = []
for o in self.operands:
sub_exprs.append("%s" % o)
return (" " + self.operator + " ").join(sub_exprs)
class AndObservationExpression(_CompoundObservationExpression):
def __init__(self, operands):
super(AndObservationExpression, self).__init__("AND", operands)
class OrObservationExpression(_CompoundObservationExpression):
def __init__(self, operands):
super(OrObservationExpression, self).__init__("OR", operands)
class FollowedByObservationExpression(_CompoundObservationExpression):
def __init__(self, operands):
super(FollowedByObservationExpression, self).__init__("FOLLOWEDBY", operands)
class ParentheticalExpression(_PatternExpression):
def __init__(self, exp):
self.expression = exp
if hasattr(exp, "root_type"):
self.root_type = exp.root_type
def __str__(self):
return "(%s)" % self.expression
class _ExpressionQualifier(_PatternExpression):
pass
class RepeatQualifier(_ExpressionQualifier):
def __init__(self, times_to_repeat):
if isinstance(times_to_repeat, IntegerConstant):
self.times_to_repeat = times_to_repeat
elif isinstance(times_to_repeat, int):
self.times_to_repeat = IntegerConstant(times_to_repeat)
else:
raise ValueError("%s is not a valid argument for a Repeat Qualifier" % times_to_repeat)
def __str__(self):
return "REPEATS %s TIMES" % self.times_to_repeat
class WithinQualifier(_ExpressionQualifier):
def __init__(self, number_of_seconds):
if isinstance(number_of_seconds, IntegerConstant):
self.number_of_seconds = number_of_seconds
elif isinstance(number_of_seconds, int):
self.number_of_seconds = IntegerConstant(number_of_seconds)
else:
raise ValueError("%s is not a valid argument for a Within Qualifier" % number_of_seconds)
def __str__(self):
return "WITHIN %s SECONDS" % self.number_of_seconds
class StartStopQualifier(_ExpressionQualifier):
def __init__(self, start_time, stop_time):
if isinstance(start_time, TimestampConstant):
self.start_time = start_time
elif isinstance(start_time, datetime.date):
self.start_time = TimestampConstant(start_time)
else:
raise ValueError("%s is not a valid argument for a Start/Stop Qualifier" % start_time)
if isinstance(stop_time, TimestampConstant):
self.stop_time = stop_time
elif isinstance(stop_time, datetime.date):
self.stop_time = TimestampConstant(stop_time)
else:
raise ValueError("%s is not a valid argument for a Start/Stop Qualifier" % stop_time)
def __str__(self):
return "START %s STOP %s" % (self.start_time, self.stop_time)
class QualifiedObservationExpression(_PatternExpression):
def __init__(self, observation_expression, qualifier):
self.observation_expression = observation_expression
self.qualifier = qualifier
def __str__(self):
return "%s %s" % (self.observation_expression, self.qualifier)