Commit a2d7634

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Merge pull request #167 from bcaller/method-propagation

Taint propagates from methods of tainted objects

2 parents d2a8189 + 8811343 commit a2d7634Copy full SHA for a2d7634

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2 files changed

+29

-17

lines changed

pyt/cfg
- stmt_visitor.py
tests/vulnerabilities
- vulnerabilities_test.py

2 files changed

+29

-17

lines changed

`‎pyt/cfg/stmt_visitor.py‎`

Lines changed: 12 additions & 15 deletions

Original file line number	Diff line number	Diff line change
`@@ -11,6 +11,7 @@`
`11`	`11`	`)`
`12`	`12`	`from ..core.ast_helper import (`
`13`	`13`	`generate_ast,`
	`14`	`+ get_call_names,`
`14`	`15`	`get_call_names_as_string`
`15`	`16`	`)`
`16`	`17`	`from ..core.module_definitions import (`
`@@ -472,14 +473,6 @@ def assignment_call_node(self, left_hand_label, ast_node):`
`472`	`473`	`call = self.visit(ast_node.value)`
`473`	`474`	`call_label = call.left_hand_side`
`474`	`475`
`475`		`- if isinstance(call, BBorBInode):`
`476`		`- # Necessary to know e.g.`
`477`		- # `image_name = image_name.replace('..', '')`
`478`		`- # is a reassignment.`
`479`		`- vars_visitor = VarsVisitor()`
`480`		`- vars_visitor.visit(ast_node.value)`
`481`		`- call.right_hand_side_variables.extend(vars_visitor.result)`
`482`		`-`
`483`	`476`	`call_assignment = AssignmentCallNode(`
`484`	`477`	`left_hand_label + ' = ' + call_label,`
`485`	`478`	`left_hand_label,`
`@@ -572,7 +565,7 @@ def visit_While(self, node):`
`572`	`565`
`573`	`566`	`return self.loop_node_skeleton(test, node)`
`574`	`567`
`575`		`- def add_blackbox_or_builtin_call(self, node, blackbox):`
	`568`	`+ def add_blackbox_or_builtin_call(self, node, blackbox):# noqa: C901`
`576`	`569`	`"""Processes a blackbox or builtin function when it is called.`
`577`	`570`	`Nothing gets assigned to ret_func_foo in the builtin/blackbox case.`
`578`	`571`
`@@ -597,14 +590,14 @@ def add_blackbox_or_builtin_call(self, node, blackbox):`
`597`	`590`	`saved_function_call_index = self.function_call_index`
`598`	`591`	`self.undecided = False`
`599`	`592`
`600`		`- call_label = LabelVisitor()`
`601`		`- call_label.visit(node)`
	`593`	`+ call_label_visitor = LabelVisitor()`
	`594`	`+ call_label_visitor.visit(node)`
`602`	`595`
`603`		`- index = call_label.result.find('(')`
	`596`	`+ call_function_label = call_label_visitor.result[:call_label_visitor.result.find('(')]`
`604`	`597`
`605`	`598`	`# Create e.g. ~call_1 = ret_func_foo`
`606`	`599`	`LHS = CALL_IDENTIFIER + 'call_' + str(saved_function_call_index)`
`607`		`- RHS = 'ret_' + call_label.result[:index] + '('`
	`600`	`+ RHS = 'ret_' + call_function_label + '('`
`608`	`601`
`609`	`602`	`call_node = BBorBInode(`
`610`	`603`	`label='',`
`@@ -613,7 +606,7 @@ def add_blackbox_or_builtin_call(self, node, blackbox):`
`613`	`606`	`right_hand_side_variables=[],`
`614`	`607`	`line_number=node.lineno,`
`615`	`608`	`path=self.filenames[-1],`
`616`		`- func_name=call_label.result[:index]`
	`609`	`+ func_name=call_function_label`
`617`	`610`	`)`
`618`	`611`	`visual_args = list()`
`619`	`612`	`rhs_vars = list()`
`@@ -657,6 +650,11 @@ def add_blackbox_or_builtin_call(self, node, blackbox):`
`657`	`650`	# `scrypt.outer(scrypt.inner(image_name), scrypt.other_inner(image_name))`
`658`	`651`	`last_return_value_of_nested_call.connect(call_node)`
`659`	`652`
	`653`	`+ call_names = list(get_call_names(node.func))`
	`654`	`+ if len(call_names) > 1:`
	`655`	`+ # taint is a RHS variable (self) of taint.lower()`
	`656`	`+ rhs_vars.append(call_names[0])`
	`657`	`+`
`660`	`658`	`if len(visual_args) > 0:`
`661`	`659`	`for arg in visual_args:`
`662`	`660`	`RHS = RHS + arg + ", "`
`@@ -667,7 +665,6 @@ def add_blackbox_or_builtin_call(self, node, blackbox):`
`667`	`665`	`call_node.label = LHS + " = " + RHS`
`668`	`666`
`669`	`667`	`call_node.right_hand_side_variables = rhs_vars`
`670`		`- # Used in get_sink_args, not using right_hand_side_variables because it is extended in assignment_call_node`
`671`	`668`	`rhs_visitor = RHSVisitor()`
`672`	`669`	`rhs_visitor.visit(node)`
`673`	`670`	`call_node.args = rhs_visitor.result`

`‎tests/vulnerabilities/vulnerabilities_test.py‎`

Lines changed: 17 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -111,8 +111,9 @@ def test_build_sanitiser_node_dict(self):`
`111`	`111`
`112`	`112`	`self.assertEqual(sanitiser_dict['escape'][0], cfg.nodes[3])`
`113`	`113`
`114`		`- def run_analysis(self, path):`
`115`		`- self.cfg_create_from_file(path)`
	`114`	`+ def run_analysis(self, path=None):`
	`115`	`+ if path:`
	`116`	`+ self.cfg_create_from_file(path)`
`116`	`117`	`cfg_list = [self.cfg]`
`117`	`118`
`118`	`119`	`FrameworkAdaptor(cfg_list, [], [], is_flask_route_function)`
`@@ -468,6 +469,20 @@ def test_yield(self):`
`468`	`469`
`469`	`470`	`self.assertAlphaEqual(str(vuln), EXPECTED_VULNERABILITY_DESCRIPTION)`
`470`	`471`
	`472`	`+ def test_method_of_taint(self):`
	`473`	`+ def assert_vulnerable(fixture):`
	`474`	`+ tree = ast.parse('TAINT = request.args.get("")\n' + fixture + '\nexecute(result)')`
	`475`	`+ self.cfg_create_from_ast(tree)`
	`476`	`+ vulnerabilities = self.run_analysis()`
	`477`	`+ self.assert_length(vulnerabilities, expected_length=1, msg=fixture)`
	`478`	`+`
	`479`	`+ assert_vulnerable('result = TAINT')`
	`480`	`+ assert_vulnerable('result = TAINT.lower()')`
	`481`	`+ assert_vulnerable('result = str(TAINT)')`
	`482`	`+ assert_vulnerable('result = str(TAINT.lower())')`
	`483`	`+ assert_vulnerable('result = repr(str("%s" % TAINT.lower().upper()))')`
	`484`	`+ assert_vulnerable('result = repr(str("{}".format(TAINT.lower())))')`
	`485`	`+`
`471`	`486`
`472`	`487`	`class EngineDjangoTest(VulnerabilitiesBaseTestCase):`
`473`	`488`	`def run_analysis(self, path):`

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2 files changed

2 files changed

`‎pyt/cfg/stmt_visitor.py‎`

`‎tests/vulnerabilities/vulnerabilities_test.py‎`

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