Python: Add tests for nested assignment

python/ql/test/library-tests/taint/general/Contexts.expected

@@ -1,5 +1,8 @@
 WARNING: Type CallContext has been deprecated and may be removed in future (Contexts.ql:6,6-17)
 WARNING: Type CallContext has been deprecated and may be removed in future (Contexts.ql:7,14-25)
+| assignment.py:1 | p0 = simple.test | Function test |
+| assignment.py:1 | p1 = simple.test | Function test |
+| assignment.py:1 | p2 = simple.test | Function test |
 | carrier.py:4 | p1 = explicit.carrier | Function __init__ |
 | carrier.py:4 | p1 = simple.test | Function __init__ |
 | carrier.py:10 | p0.attr = simple.test | Function get_attr |

python/ql/test/library-tests/taint/general/TestDefn.expected

@@ -1,3 +1,6 @@
+| assignment.py:5 | SOURCE | assignment.py:5 | Taint simple.test | a |
+| assignment.py:7 | a | assignment.py:7 | Taint simple.test | b |
+| assignment.py:13 | SOURCE | assignment.py:13 | Taint simple.test | t2 |
 | carrier.py:4 | ParameterDefinition | carrier.py:4 | Taint explicit.carrier | arg |
 | carrier.py:4 | ParameterDefinition | carrier.py:4 | Taint simple.test | arg |
 | carrier.py:10 | ParameterDefinition | carrier.py:10 | Taint .attr = simple.test | self |

python/ql/test/library-tests/taint/general/TestSource.expected

@@ -1,3 +1,5 @@
+| assignment.py:5 | SOURCE | simple.test |
+| assignment.py:13 | SOURCE | simple.test |
 | carrier.py:17 | SOURCE | simple.test |
 | carrier.py:21 | TAINT_CARRIER_SOURCE | explicit.carrier |
 | carrier.py:25 | SOURCE | simple.test |

python/ql/test/library-tests/taint/general/TestStep.expected

@@ -103,6 +103,7 @@
 | scissors | rockpaperscissors.py:29 | SCISSORS |  | --> | scissors | rockpaperscissors.py:31 | x |  |
 | scissors | rockpaperscissors.py:30 | x |  | --> | paper | rockpaperscissors.py:30 | Attribute() |  |
 | scissors | rockpaperscissors.py:31 | x |  | --> | scissors | rockpaperscissors.py:6 | arg | p0 = scissors |
+| sequence of simple.test | assignment.py:13 | Tuple |  | --> | sequence of [simple.test] | assignment.py:13 | Tuple |  |
 | sequence of simple.test | test.py:168 | List |  | --> | sequence of simple.test | test.py:170 | l |  |
 | sequence of simple.test | test.py:168 | List |  | --> | sequence of simple.test | test.py:174 | l |  |
 | sequence of simple.test | test.py:170 | SSA variable x |  | --> | sequence of simple.test | test.py:172 | x |  |
@@ -112,6 +113,13 @@
 | sequence of simple.test | test.py:208 | List |  | --> | sequence of simple.test | test.py:209 | seq |  |
 | sequence of simple.test | test.py:209 | seq |  | --> | simple.test | test.py:209 | For |  |
 | sequence of simple.test | test.py:213 | flow_in_generator() |  | --> | simple.test | test.py:213 | For |  |
+| simple.test | assignment.py:5 | SOURCE |  | --> | sequence of simple.test | assignment.py:5 | Tuple |  |
+| simple.test | assignment.py:5 | SOURCE |  | --> | simple.test | assignment.py:6 | a |  |
+| simple.test | assignment.py:5 | SOURCE |  | --> | simple.test | assignment.py:7 | a |  |
+| simple.test | assignment.py:7 | a |  | --> | sequence of simple.test | assignment.py:7 | Tuple |  |
+| simple.test | assignment.py:7 | a |  | --> | simple.test | assignment.py:8 | b |  |
+| simple.test | assignment.py:13 | SOURCE |  | --> | sequence of simple.test | assignment.py:13 | Tuple |  |
+| simple.test | assignment.py:13 | SOURCE |  | --> | simple.test | assignment.py:14 | t2 |  |
 | simple.test | carrier.py:4 | arg | p1 = simple.test | --> | simple.test | carrier.py:5 | arg | p1 = simple.test |
 | simple.test | carrier.py:17 | SOURCE |  | --> | .attr = simple.test | carrier.py:17 | ImplicitCarrier() |  |
 | simple.test | carrier.py:17 | SOURCE |  | --> | simple.test | carrier.py:4 | arg | p1 = simple.test |

python/ql/test/library-tests/taint/general/TestTaint.expected

@@ -0,0 +1,8 @@
+| assignment.py:6 | swap_taint | a | simple.test |
+| assignment.py:6 | swap_taint | b | NO TAINT |
+| assignment.py:8 | swap_taint | a | NO TAINT |
+| assignment.py:8 | swap_taint | b | simple.test |
+| assignment.py:14 | nested_assignment | s1 | NO TAINT |
+| assignment.py:14 | nested_assignment | s2 | NO TAINT |
+| assignment.py:14 | nested_assignment | t1 | NO TAINT |
+| assignment.py:14 | nested_assignment | t2 | simple.test |

python/ql/test/library-tests/taint/general/TestTaint.ql

@@ -0,0 +1,18 @@
+import python
+import semmle.python.security.TaintTracking
+import TaintLib
+
+from Call call, Expr arg, string taint_string
+where
+    call.getLocation().getFile().getShortName() = "assignment.py" and
+    call.getFunc().(Name).getId() = "test" and
+    arg = call.getAnArg() and
+    (
+        not exists(TaintedNode tainted | tainted.getAstNode() = arg) and
+        taint_string = "NO TAINT"
+        or
+        exists(TaintedNode tainted | tainted.getAstNode() = arg |
+            taint_string = tainted.getTaintKind().toString()
+        )
+    )
+select arg.getLocation().toString(), call.getScope().(Function).getName(), arg.toString(), taint_string

python/ql/test/library-tests/taint/general/TestVar.expected

@@ -1,3 +1,7 @@
+| assignment.py:5 | a_0 | assignment.py:5 | Taint simple.test |
+| assignment.py:6 | a_1 | assignment.py:6 | Taint simple.test |
+| assignment.py:7 | b_1 | assignment.py:7 | Taint simple.test |
+| assignment.py:13 | t2_0 | assignment.py:13 | Taint simple.test |
 | carrier.py:4 | arg_0 | carrier.py:4 | Taint explicit.carrier |
 | carrier.py:4 | arg_0 | carrier.py:4 | Taint simple.test |
 | carrier.py:5 | self_1 | carrier.py:5 | Taint .attr = explicit.carrier |

python/ql/test/library-tests/taint/general/assignment.py

@@ -0,0 +1,14 @@
+def test(*args):
+    pass
+
+def swap_taint():
+    a, b = SOURCE, "safe"
+    test(a, b)
+    a, b = b, a
+    test(a, b)
+
+def nested_assignment():
+    # A contrived example, that is a bit silly (and is not even iterable unpacking).
+    # We do handle this case though.
+    ((t1, s1), t2, s2) = ((SOURCE, "safe"), SOURCE, "safe")
+    test(t1, s1, t2, s2)