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cti-python-stix2
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Merge pull request #545 from chisholm/complete_pattern_visitor 

Complete pattern visitor
pull/1/head
Chris Lenk 2022-05-02 11:00:34 -04:00 committed by GitHub
parent 17445a085c 3dba3f74f9
commit aac27374b3
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 198 additions and 51 deletions
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93
stix2/pattern_visitor.py
View File

@ -53,22 +53,32 @@ def same_boolean_operator(current_op, op_token):
class STIXPatternVisitorForSTIX2():
classes = {}
def __init__(self, parser_class, module_suffix=None, module_name=None):
self.parser_class = parser_class
if module_suffix and module_name:
self.module_suffix = module_suffix
self.module = importlib.import_module(module_name)
else:
self.module_suffix = self.module = None
def get_class(self, class_name):
if class_name in STIXPatternVisitorForSTIX2.classes:
return STIXPatternVisitorForSTIX2.classes[class_name]
else:
return None
klass = None
if self.module:
class_name_suffix = class_name + "For" + self.module_suffix
member = getattr(self.module, class_name_suffix, None)
if member and inspect.isclass(member):
klass = member
def instantiate(self, klass_name, *args):
klass_to_instantiate = None
if self.module_suffix:
klass_to_instantiate = self.get_class(klass_name + "For" + self.module_suffix)
if not klass_to_instantiate:
# use the classes in python_stix2
klass_to_instantiate = globals()[klass_name]
return klass_to_instantiate(*args)
if not klass:
klass = globals()[class_name]
return klass
def instantiate(self, klass_name, *args, **kwargs):
klass_to_instantiate = self.get_class(klass_name)
return klass_to_instantiate(*args, **kwargs)
# Visit a parse tree produced by STIXPatternParser#pattern.
def visitPattern(self, ctx):
@ -81,7 +91,7 @@ class STIXPatternVisitorForSTIX2():
if len(children) == 1:
return children[0]
else:
return FollowedByObservationExpression([children[0], children[2]])
return self.instantiate("FollowedByObservationExpression", [children[0], children[2]])
# Visit a parse tree produced by STIXPatternParser#observationExpressionOr.
def visitObservationExpressionOr(self, ctx):
@ -231,17 +241,17 @@ class STIXPatternVisitorForSTIX2():
if not check_for_valid_timetamp_syntax(children[3].value):
raise (ValueError("Stop time is not a legal timestamp"))
return StartStopQualifier(children[1], children[3])
return self.instantiate("StartStopQualifier", children[1], children[3])
# Visit a parse tree produced by STIXPatternParser#withinQualifier.
def visitWithinQualifier(self, ctx):
children = self.visitChildren(ctx)
return WithinQualifier(children[1])
return self.instantiate("WithinQualifier", children[1])
# Visit a parse tree produced by STIXPatternParser#repeatedQualifier.
def visitRepeatedQualifier(self, ctx):
children = self.visitChildren(ctx)
return RepeatQualifier(children[1])
return self.instantiate("RepeatQualifier", children[1])
# Visit a parse tree produced by STIXPatternParser#objectPath.
def visitObjectPath(self, ctx):
@ -326,26 +336,26 @@ class STIXPatternVisitorForSTIX2():
def visitTerminal(self, node):
if node.symbol.type == self.parser_class.IntPosLiteral or node.symbol.type == self.parser_class.IntNegLiteral:
return IntegerConstant(node.getText())
return self.instantiate("IntegerConstant", node.getText())
elif node.symbol.type == self.parser_class.FloatPosLiteral or node.symbol.type == self.parser_class.FloatNegLiteral:
return FloatConstant(node.getText())
return self.instantiate("FloatConstant", node.getText())
elif node.symbol.type == self.parser_class.HexLiteral:
return HexConstant(node.getText(), from_parse_tree=True)
return self.instantiate("HexConstant", node.getText(), from_parse_tree=True)
elif node.symbol.type == self.parser_class.BinaryLiteral:
return BinaryConstant(node.getText(), from_parse_tree=True)
return self.instantiate("BinaryConstant", node.getText(), from_parse_tree=True)
elif node.symbol.type == self.parser_class.StringLiteral:
if node.getText()[0] == "'" and node.getText()[-1] == "'":
return StringConstant(node.getText()[1:-1], from_parse_tree=True)
return self.instantiate("StringConstant", node.getText()[1:-1], from_parse_tree=True)
else:
raise ParseException("The pattern does not start and end with a single quote")
elif node.symbol.type == self.parser_class.BoolLiteral:
return BooleanConstant(node.getText())
return self.instantiate("BooleanConstant", node.getText())
elif node.symbol.type == self.parser_class.TimestampLiteral:
value = node.getText()
# STIX 2.1 uses a special timestamp literal syntax
if value.startswith("t"):
value = value[2:-1]
return TimestampConstant(value)
return self.instantiate("TimestampConstant", value)
else:
return node
@ -356,37 +366,14 @@ class STIXPatternVisitorForSTIX2():
aggregate = [nextResult]
return aggregate
# This class defines a complete generic visitor for a parse tree produced by STIXPatternParser.
class STIXPatternVisitorForSTIX21(STIXPatternVisitorForSTIX2, STIXPatternVisitor21):
classes = {}
def __init__(self, module_suffix, module_name):
if module_suffix and module_name:
self.module_suffix = module_suffix
if not STIXPatternVisitorForSTIX2.classes:
module = importlib.import_module(module_name)
for k, c in inspect.getmembers(module, inspect.isclass):
STIXPatternVisitorForSTIX2.classes[k] = c
else:
self.module_suffix = None
self.parser_class = STIXPatternParser21
super(STIXPatternVisitor21, self).__init__()
pass
class STIXPatternVisitorForSTIX20(STIXPatternVisitorForSTIX2, STIXPatternVisitor20):
classes = {}
def __init__(self, module_suffix, module_name):
if module_suffix and module_name:
self.module_suffix = module_suffix
if not STIXPatternVisitorForSTIX2.classes:
module = importlib.import_module(module_name)
for k, c in inspect.getmembers(module, inspect.isclass):
STIXPatternVisitorForSTIX2.classes[k] = c
else:
self.module_suffix = None
self.parser_class = STIXPatternParser20
super(STIXPatternVisitor20, self).__init__()
pass
def create_pattern_object(pattern, module_suffix="", module_name="", version=DEFAULT_VERSION):
@ -397,10 +384,14 @@ def create_pattern_object(pattern, module_suffix="", module_name="", version=DEF
if version == "2.1":
pattern_class = Pattern21
visitor_class = STIXPatternVisitorForSTIX21
parser_class = STIXPatternParser21
else:
pattern_class = Pattern20
visitor_class = STIXPatternVisitorForSTIX20
parser_class = STIXPatternParser20
pattern_obj = pattern_class(pattern)
builder = visitor_class(module_suffix, module_name)
builder = visitor_class(
parser_class, module_suffix, module_name,
)
return pattern_obj.visit(builder)

18
stix2/test/v20/pattern_ast_overrides.py Normal file
View File

@ -0,0 +1,18 @@
"""
AST node class overrides for testing the pattern AST builder.
"""
from stix2.patterns import (
EqualityComparisonExpression, StartStopQualifier, StringConstant,
)
class EqualityComparisonExpressionForTesting(EqualityComparisonExpression):
pass
class StringConstantForTesting(StringConstant):
pass
class StartStopQualifierForTesting(StartStopQualifier):
pass

60
stix2/test/v20/test_pattern_expressions.py
View File

@ -5,8 +5,13 @@ import pytz
import stix2
from stix2.pattern_visitor import create_pattern_object
import stix2.patterns
import stix2.utils
# flake8 does not approve of star imports.
# flake8: noqa: F405
from .pattern_ast_overrides import *
def test_create_comparison_expression():
exp = stix2.EqualityComparisonExpression(
@ -587,3 +592,58 @@ def test_parsing_illegal_start_stop_qualified_expression():
def test_list_constant():
patt_obj = create_pattern_object("[network-traffic:src_ref.value IN ('10.0.0.0', '10.0.0.1', '10.0.0.2')]", version="2.0")
assert str(patt_obj) == "[network-traffic:src_ref.value IN ('10.0.0.0', '10.0.0.1', '10.0.0.2')]"
def test_ast_class_override_comp_equals():
patt_ast = create_pattern_object(
"[a:b=1]", "Testing", "stix2.test.v20.pattern_ast_overrides",
version="2.0",
)
assert isinstance(patt_ast, stix2.patterns.ObservationExpression)
assert isinstance(patt_ast.operand, EqualityComparisonExpressionForTesting)
assert str(patt_ast) == "[a:b = 1]"
def test_ast_class_override_string_constant():
patt_ast = create_pattern_object(
"[a:'b'[1].'c' < 'foo']", "Testing",
"stix2.test.v20.pattern_ast_overrides",
version="2.0",
)
assert isinstance(patt_ast, stix2.patterns.ObservationExpression)
assert isinstance(
patt_ast.operand, stix2.patterns.LessThanComparisonExpression,
)
assert isinstance(
patt_ast.operand.lhs.property_path[0].property_name,
str,
)
assert isinstance(
patt_ast.operand.lhs.property_path[1].property_name,
str,
)
assert isinstance(patt_ast.operand.rhs, StringConstantForTesting)
assert str(patt_ast) == "[a:'b'[1].c < 'foo']"
def test_ast_class_override_startstop_qualifier():
patt_ast = create_pattern_object(
"[a:b=1] START '1993-01-20T01:33:52.592Z' STOP '2001-08-19T23:50:23.129Z'",
"Testing", "stix2.test.v20.pattern_ast_overrides", version="2.0",
)
assert isinstance(patt_ast, stix2.patterns.QualifiedObservationExpression)
assert isinstance(
patt_ast.observation_expression, stix2.patterns.ObservationExpression,
)
assert isinstance(
patt_ast.observation_expression.operand,
EqualityComparisonExpressionForTesting,
)
assert isinstance(
patt_ast.qualifier, StartStopQualifierForTesting,
)
assert str(patt_ast) == "[a:b = 1] START '1993-01-20T01:33:52.592Z' STOP '2001-08-19T23:50:23.129Z'"

18
stix2/test/v21/pattern_ast_overrides.py Normal file
View File

@ -0,0 +1,18 @@
"""
AST node class overrides for testing the pattern AST builder.
"""
from stix2.patterns import (
EqualityComparisonExpression, StartStopQualifier, StringConstant,
)
class EqualityComparisonExpressionForTesting(EqualityComparisonExpression):
pass
class StringConstantForTesting(StringConstant):
pass
class StartStopQualifierForTesting(StartStopQualifier):
pass

60
stix2/test/v21/test_pattern_expressions.py
View File

@ -6,8 +6,13 @@ from stix2patterns.exceptions import ParseException
import stix2
from stix2.pattern_visitor import create_pattern_object
import stix2.patterns
import stix2.utils
# flake8 does not approve of star imports.
# flake8: noqa: F405
from .pattern_ast_overrides import *
def test_create_comparison_expression():
exp = stix2.EqualityComparisonExpression(
@ -747,3 +752,58 @@ def test_parsing_multiple_slashes_quotes():
def test_parse_error():
with pytest.raises(ParseException):
create_pattern_object("[ file: name = 'weirdname]", version="2.1")
def test_ast_class_override_comp_equals():
patt_ast = create_pattern_object(
"[a:b=1]", "Testing", "stix2.test.v21.pattern_ast_overrides",
version="2.1",
)
assert isinstance(patt_ast, stix2.patterns.ObservationExpression)
assert isinstance(patt_ast.operand, EqualityComparisonExpressionForTesting)
assert str(patt_ast) == "[a:b = 1]"
def test_ast_class_override_string_constant():
patt_ast = create_pattern_object(
"[a:'b'[1].'c' < 'foo']", "Testing",
"stix2.test.v21.pattern_ast_overrides",
version="2.1",
)
assert isinstance(patt_ast, stix2.patterns.ObservationExpression)
assert isinstance(
patt_ast.operand, stix2.patterns.LessThanComparisonExpression,
)
assert isinstance(
patt_ast.operand.lhs.property_path[0].property_name,
str,
)
assert isinstance(
patt_ast.operand.lhs.property_path[1].property_name,
str,
)
assert isinstance(patt_ast.operand.rhs, StringConstantForTesting)
assert str(patt_ast) == "[a:'b'[1].c < 'foo']"
def test_ast_class_override_startstop_qualifier():
patt_ast = create_pattern_object(
"[a:b=1] START t'1993-01-20T01:33:52.592Z' STOP t'2001-08-19T23:50:23.129Z'",
"Testing", "stix2.test.v21.pattern_ast_overrides", version="2.1",
)
assert isinstance(patt_ast, stix2.patterns.QualifiedObservationExpression)
assert isinstance(
patt_ast.observation_expression, stix2.patterns.ObservationExpression,
)
assert isinstance(
patt_ast.observation_expression.operand,
EqualityComparisonExpressionForTesting,
)
assert isinstance(
patt_ast.qualifier, StartStopQualifierForTesting,
)
assert str(patt_ast) == "[a:b = 1] START t'1993-01-20T01:33:52.592Z' STOP t'2001-08-19T23:50:23.129Z'"