bpo-36842: Fix reference leak in tests by running out-of-proc

Lib/test/audit-tests.py

@@ -0,0 +1,269 @@
+"""This script contains the actual auditing tests.
+
+It should not be imported directly, but should be run by the test_audit
+module with arguments identifying each test.
+
+"""
+
+import contextlib
+import sys
+
+
+class TestHook:
+    """Used in standard hook tests to collect any logged events.
+
+    Should be used in a with block to ensure that it has no impact
+    after the test completes.
+    """
+
+    def __init__(self, raise_on_events=None, exc_type=RuntimeError):
+        self.raise_on_events = raise_on_events or ()
+        self.exc_type = exc_type
+        self.seen = []
+        self.closed = False
+
+    def __enter__(self, *a):
+        sys.addaudithook(self)
+        return self
+
+    def __exit__(self, *a):
+        self.close()
+
+    def close(self):
+        self.closed = True
+
+    @property
+    def seen_events(self):
+        return [i[0] for i in self.seen]
+
+    def __call__(self, event, args):
+        if self.closed:
+            return
+        self.seen.append((event, args))
+        if event in self.raise_on_events:
+            raise self.exc_type("saw event " + event)
+
+
+class TestFinalizeHook:
+    """Used in the test_finalize_hooks function to ensure that hooks
+    are correctly cleaned up, that they are notified about the cleanup,
+    and are unable to prevent it.
+    """
+
+    def __init__(self):
+        print("Created", id(self), file=sys.stdout, flush=True)
+
+    def __call__(self, event, args):
+        # Avoid recursion when we call id() below
+        if event == "builtins.id":
+            return
+
+        print(event, id(self), file=sys.stdout, flush=True)
+
+        if event == "cpython._PySys_ClearAuditHooks":
+            raise RuntimeError("Should be ignored")
+        elif event == "cpython.PyInterpreterState_Clear":
+            raise RuntimeError("Should be ignored")
+
+
+# Simple helpers, since we are not in unittest here
+def assertEqual(x, y):
+    if x != y:
+        raise AssertionError(f"{x!r} should equal {y!r}")
+
+
+def assertIn(el, series):
+    if el not in series:
+        raise AssertionError(f"{el!r} should be in {series!r}")
+
+
+def assertNotIn(el, series):
+    if el in series:
+        raise AssertionError(f"{el!r} should not be in {series!r}")
+
+
+def assertSequenceEqual(x, y):
+    if len(x) != len(y):
+        raise AssertionError(f"{x!r} should equal {y!r}")
+    if any(ix != iy for ix, iy in zip(x, y)):
+        raise AssertionError(f"{x!r} should equal {y!r}")
+
+
+@contextlib.contextmanager
+def assertRaises(ex_type):
+    try:
+        yield
+        assert False, f"expected {ex_type}"
+    except BaseException as ex:
+        if isinstance(ex, AssertionError):
+            raise
+        assert type(ex) is ex_type, f"{ex} should be {ex_type}"
+
+
+def test_basic():
+    with TestHook() as hook:
+        sys.audit("test_event", 1, 2, 3)
+        assertEqual(hook.seen[0][0], "test_event")
+        assertEqual(hook.seen[0][1], (1, 2, 3))
+
+
+def test_block_add_hook():
+    # Raising an exception should prevent a new hook from being added,
+    # but will not propagate out.
+    with TestHook(raise_on_events="sys.addaudithook") as hook1:
+        with TestHook() as hook2:
+            sys.audit("test_event")
+            assertIn("test_event", hook1.seen_events)
+            assertNotIn("test_event", hook2.seen_events)
+
+
+def test_block_add_hook_baseexception():
+    # Raising BaseException will propagate out when adding a hook
+    with assertRaises(BaseException):
+        with TestHook(
+            raise_on_events="sys.addaudithook", exc_type=BaseException
+        ) as hook1:
+            # Adding this next hook should raise BaseException
+            with TestHook() as hook2:
+                pass
+
+
+def test_finalize_hooks():
+    sys.addaudithook(TestFinalizeHook())
+
+
+def test_pickle():
+    import pickle
+
+    class PicklePrint:
+        def __reduce_ex__(self, p):
+            return str, ("Pwned!",)
+
+    payload_1 = pickle.dumps(PicklePrint())
+    payload_2 = pickle.dumps(("a", "b", "c", 1, 2, 3))
+
+    # Before we add the hook, ensure our malicious pickle loads
+    assertEqual("Pwned!", pickle.loads(payload_1))
+
+    with TestHook(raise_on_events="pickle.find_class") as hook:
+        with assertRaises(RuntimeError):
+            # With the hook enabled, loading globals is not allowed
+            pickle.loads(payload_1)
+        # pickles with no globals are okay
+        pickle.loads(payload_2)
+
+
+def test_monkeypatch():
+    class A:
+        pass
+
+    class B:
+        pass
+
+    class C(A):
+        pass
+
+    a = A()
+
+    with TestHook() as hook:
+        # Catch name changes
+        C.__name__ = "X"
+        # Catch type changes
+        C.__bases__ = (B,)
+        # Ensure bypassing __setattr__ is still caught
+        type.__dict__["__bases__"].__set__(C, (B,))
+        # Catch attribute replacement
+        C.__init__ = B.__init__
+        # Catch attribute addition
+        C.new_attr = 123
+        # Catch class changes
+        a.__class__ = B
+
+    actual = [(a[0], a[1]) for e, a in hook.seen if e == "object.__setattr__"]
+    assertSequenceEqual(
+        [(C, "__name__"), (C, "__bases__"), (C, "__bases__"), (a, "__class__")], actual
+    )
+
+
+def test_open():
+    # SSLContext.load_dh_params uses _Py_fopen_obj rather than normal open()
+    try:
+        import ssl
+
+        load_dh_params = ssl.create_default_context().load_dh_params
+    except ImportError:
+        load_dh_params = None
+
+    # Try a range of "open" functions.
+    # All of them should fail
+    with TestHook(raise_on_events={"open"}) as hook:
+        for fn, *args in [
+            (open, sys.argv[2], "r"),
+            (open, sys.executable, "rb"),
+            (open, 3, "wb"),
+            (open, sys.argv[2], "w", -1, None, None, None, False, lambda *a: 1),
+            (load_dh_params, sys.argv[2]),
+        ]:
+            if not fn:
+                continue
+            with assertRaises(RuntimeError):
+                fn(*args)
+
+    actual_mode = [(a[0], a[1]) for e, a in hook.seen if e == "open" and a[1]]
+    actual_flag = [(a[0], a[2]) for e, a in hook.seen if e == "open" and not a[1]]
+    assertSequenceEqual(
+        [
+            i
+            for i in [
+                (sys.argv[2], "r"),
+                (sys.executable, "r"),
+                (3, "w"),
+                (sys.argv[2], "w"),
+                (sys.argv[2], "rb") if load_dh_params else None,
+            ]
+            if i is not None
+        ],
+        actual_mode,
+    )
+    assertSequenceEqual([], actual_flag)
+
+
+def test_cantrace():
+    traced = []
+
+    def trace(frame, event, *args):
+        if frame.f_code == TestHook.__call__.__code__:
+            traced.append(event)
+
+    old = sys.settrace(trace)
+    try:
+        with TestHook() as hook:
+            # No traced call
+            eval("1")
+
+            # No traced call
+            hook.__cantrace__ = False
+            eval("2")
+
+            # One traced call
+            hook.__cantrace__ = True
+            eval("3")
+
+            # Two traced calls (writing to private member, eval)
+            hook.__cantrace__ = 1
+            eval("4")
+
+            # One traced call (writing to private member)
+            hook.__cantrace__ = 0
+    finally:
+        sys.settrace(old)
+
+    assertSequenceEqual(["call"] * 4, traced)
+
+
+if __name__ == "__main__":
+    from test.libregrtest.setup import suppress_msvcrt_asserts
+    suppress_msvcrt_asserts(False)
+
+    test = sys.argv[1]
+    globals()[test]()

Lib/test/libregrtest/setup.py

@@ -83,27 +83,7 @@ def setup_tests(ns):
     if ns.threshold is not None:
         gc.set_threshold(ns.threshold)
 
-    try:
-        import msvcrt
-    except ImportError:
-        pass
-    else:
-        msvcrt.SetErrorMode(msvcrt.SEM_FAILCRITICALERRORS|
-                            msvcrt.SEM_NOALIGNMENTFAULTEXCEPT|
-                            msvcrt.SEM_NOGPFAULTERRORBOX|
-                            msvcrt.SEM_NOOPENFILEERRORBOX)
-        try:
-            msvcrt.CrtSetReportMode
-        except AttributeError:
-            # release build
-            pass
-        else:
-            for m in [msvcrt.CRT_WARN, msvcrt.CRT_ERROR, msvcrt.CRT_ASSERT]:
-                if ns.verbose and ns.verbose >= 2:
-                    msvcrt.CrtSetReportMode(m, msvcrt.CRTDBG_MODE_FILE)
-                    msvcrt.CrtSetReportFile(m, msvcrt.CRTDBG_FILE_STDERR)
-                else:
-                    msvcrt.CrtSetReportMode(m, 0)
+    suppress_msvcrt_asserts(ns.verbose and ns.verbose >= 2)
 
     support.use_resources = ns.use_resources
 
@@ -114,6 +94,31 @@ def _test_audit_hook(name, args):
         sys.addaudithook(_test_audit_hook)
 
 
+def suppress_msvcrt_asserts(verbose):
+    try:
+        import msvcrt
+    except ImportError:
+        return
+
+    msvcrt.SetErrorMode(msvcrt.SEM_FAILCRITICALERRORS|
+                        msvcrt.SEM_NOALIGNMENTFAULTEXCEPT|
+                        msvcrt.SEM_NOGPFAULTERRORBOX|
+                        msvcrt.SEM_NOOPENFILEERRORBOX)
+    try:
+        msvcrt.CrtSetReportMode
+    except AttributeError:
+        # release build
+        return
+
+    for m in [msvcrt.CRT_WARN, msvcrt.CRT_ERROR, msvcrt.CRT_ASSERT]:
+        if verbose:
+            msvcrt.CrtSetReportMode(m, msvcrt.CRTDBG_MODE_FILE)
+            msvcrt.CrtSetReportFile(m, msvcrt.CRTDBG_FILE_STDERR)
+        else:
+            msvcrt.CrtSetReportMode(m, 0)
+
+
+
 def replace_stdout():
     """Set stdout encoder error handler to backslashreplace (as stderr error
     handler) to avoid UnicodeEncodeError when printing a traceback"""