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gh-89811: Check for valid tp_version_tag in specializer (GH-113558)

This commit is contained in:
Peter Lazorchak 2024-01-10 21:33:05 -08:00 committed by GitHub
parent c65ae26f2b
commit f653caa5a8
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4 changed files with 243 additions and 3 deletions
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185
Lib/test/test_type_cache.py
View File

@ -1,5 +1,6 @@
""" Tests for the internal type cache in CPython. """
import unittest
import dis
from test import support
from test.support import import_helper
try:
@ -8,8 +9,11 @@ except ImportError:
_clear_type_cache = None
# Skip this test if the _testcapi module isn't available.
type_get_version = import_helper.import_module('_testcapi').type_get_version
type_assign_version = import_helper.import_module('_testcapi').type_assign_version
_testcapi = import_helper.import_module("_testcapi")
type_get_version = _testcapi.type_get_version
type_assign_specific_version_unsafe = _testcapi.type_assign_specific_version_unsafe
type_assign_version = _testcapi.type_assign_version
type_modified = _testcapi.type_modified
@support.cpython_only
@ -56,6 +60,183 @@ class TypeCacheTests(unittest.TestCase):
self.assertNotEqual(type_get_version(C), 0)
self.assertNotEqual(type_get_version(C), c_ver)
def test_type_assign_specific_version(self):
"""meta-test for type_assign_specific_version_unsafe"""
class C:
pass
type_assign_version(C)
orig_version = type_get_version(C)
self.assertNotEqual(orig_version, 0)
type_modified(C)
type_assign_specific_version_unsafe(C, orig_version + 5)
type_assign_version(C) # this should do nothing
new_version = type_get_version(C)
self.assertEqual(new_version, orig_version + 5)
_clear_type_cache()
@support.cpython_only
class TypeCacheWithSpecializationTests(unittest.TestCase):
def tearDown(self):
_clear_type_cache()
def _assign_and_check_valid_version(self, user_type):
type_modified(user_type)
type_assign_version(user_type)
self.assertNotEqual(type_get_version(user_type), 0)
def _assign_and_check_version_0(self, user_type):
type_modified(user_type)
type_assign_specific_version_unsafe(user_type, 0)
self.assertEqual(type_get_version(user_type), 0)
def _all_opnames(self, func):
return set(instr.opname for instr in dis.Bytecode(func, adaptive=True))
def _check_specialization(self, func, arg, opname, *, should_specialize):
self.assertIn(opname, self._all_opnames(func))
for _ in range(100):
func(arg)
if should_specialize:
self.assertNotIn(opname, self._all_opnames(func))
else:
self.assertIn(opname, self._all_opnames(func))
def test_class_load_attr_specialization_user_type(self):
class A:
def foo(self):
pass
self._assign_and_check_valid_version(A)
def load_foo_1(type_):
type_.foo
self._check_specialization(load_foo_1, A, "LOAD_ATTR", should_specialize=True)
del load_foo_1
self._assign_and_check_version_0(A)
def load_foo_2(type_):
return type_.foo
self._check_specialization(load_foo_2, A, "LOAD_ATTR", should_specialize=False)
def test_class_load_attr_specialization_static_type(self):
self._assign_and_check_valid_version(str)
self._assign_and_check_valid_version(bytes)
def get_capitalize_1(type_):
return type_.capitalize
self._check_specialization(get_capitalize_1, str, "LOAD_ATTR", should_specialize=True)
self.assertEqual(get_capitalize_1(str)('hello'), 'Hello')
self.assertEqual(get_capitalize_1(bytes)(b'hello'), b'Hello')
del get_capitalize_1
# Permanently overflow the static type version counter, and force str and bytes
# to have tp_version_tag == 0
for _ in range(2**16):
type_modified(str)
type_assign_version(str)
type_modified(bytes)
type_assign_version(bytes)
self.assertEqual(type_get_version(str), 0)
self.assertEqual(type_get_version(bytes), 0)
def get_capitalize_2(type_):
return type_.capitalize
self._check_specialization(get_capitalize_2, str, "LOAD_ATTR", should_specialize=False)
self.assertEqual(get_capitalize_2(str)('hello'), 'Hello')
self.assertEqual(get_capitalize_2(bytes)(b'hello'), b'Hello')
def test_property_load_attr_specialization_user_type(self):
class G:
@property
def x(self):
return 9
self._assign_and_check_valid_version(G)
def load_x_1(instance):
instance.x
self._check_specialization(load_x_1, G(), "LOAD_ATTR", should_specialize=True)
del load_x_1
self._assign_and_check_version_0(G)
def load_x_2(instance):
instance.x
self._check_specialization(load_x_2, G(), "LOAD_ATTR", should_specialize=False)
def test_store_attr_specialization_user_type(self):
class B:
__slots__ = ("bar",)
self._assign_and_check_valid_version(B)
def store_bar_1(type_):
type_.bar = 10
self._check_specialization(store_bar_1, B(), "STORE_ATTR", should_specialize=True)
del store_bar_1
self._assign_and_check_version_0(B)
def store_bar_2(type_):
type_.bar = 10
self._check_specialization(store_bar_2, B(), "STORE_ATTR", should_specialize=False)
def test_class_call_specialization_user_type(self):
class F:
def __init__(self):
pass
self._assign_and_check_valid_version(F)
def call_class_1(type_):
type_()
self._check_specialization(call_class_1, F, "CALL", should_specialize=True)
del call_class_1
self._assign_and_check_version_0(F)
def call_class_2(type_):
type_()
self._check_specialization(call_class_2, F, "CALL", should_specialize=False)
def test_to_bool_specialization_user_type(self):
class H:
pass
self._assign_and_check_valid_version(H)
def to_bool_1(instance):
not instance
self._check_specialization(to_bool_1, H(), "TO_BOOL", should_specialize=True)
del to_bool_1
self._assign_and_check_version_0(H)
def to_bool_2(instance):
not instance
self._check_specialization(to_bool_2, H(), "TO_BOOL", should_specialize=False)
if __name__ == "__main__":
unittest.main()

2
Misc/NEWS.d/next/Core and Builtins/2024-01-03-12-19-37.gh-issue-89811.cZOj6d.rst Normal file
View File

@ -0,0 +1,2 @@
Check for a valid ``tp_version_tag`` before performing bytecode specializations that
rely on this value being usable.

29
Modules/_testcapimodule.c
View File

@ -2409,6 +2409,32 @@ type_get_version(PyObject *self, PyObject *type)
return res;
}
static PyObject *
type_modified(PyObject *self, PyObject *type)
{
if (!PyType_Check(type)) {
PyErr_SetString(PyExc_TypeError, "argument must be a type");
return NULL;
}
PyType_Modified((PyTypeObject *)type);
Py_RETURN_NONE;
}
// Circumvents standard version assignment machinery - use with caution and only on
// short-lived heap types
static PyObject *
type_assign_specific_version_unsafe(PyObject *self, PyObject *args)
{
PyTypeObject *type;
unsigned int version;
if (!PyArg_ParseTuple(args, "Oi:type_assign_specific_version_unsafe", &type, &version)) {
return NULL;
}
assert(!PyType_HasFeature(type, Py_TPFLAGS_IMMUTABLETYPE));
type->tp_version_tag = version;
type->tp_flags |= Py_TPFLAGS_VALID_VERSION_TAG;
Py_RETURN_NONE;
}
static PyObject *
type_assign_version(PyObject *self, PyObject *type)
@ -3342,6 +3368,9 @@ static PyMethodDef TestMethods[] = {
{"test_py_is_macros", test_py_is_macros, METH_NOARGS},
{"test_py_is_funcs", test_py_is_funcs, METH_NOARGS},
{"type_get_version", type_get_version, METH_O, PyDoc_STR("type->tp_version_tag")},
{"type_modified", type_modified, METH_O, PyDoc_STR("PyType_Modified")},
{"type_assign_specific_version_unsafe", type_assign_specific_version_unsafe, METH_VARARGS,
PyDoc_STR("forcefully assign type->tp_version_tag")},
{"type_assign_version", type_assign_version, METH_O, PyDoc_STR("PyUnstable_Type_AssignVersionTag")},
{"type_get_tp_bases", type_get_tp_bases, METH_O},
{"type_get_tp_mro", type_get_tp_mro, METH_O},

30
Python/specialize.c
View File

@ -586,6 +586,7 @@ _PyCode_Quicken(PyCodeObject *code)
static int function_kind(PyCodeObject *code);
static bool function_check_args(PyObject *o, int expected_argcount, int opcode);
static uint32_t function_get_version(PyObject *o, int opcode);
static uint32_t type_get_version(PyTypeObject *t, int opcode);
static int
specialize_module_load_attr(
@ -874,6 +875,9 @@ _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name)
PyObject *descr = NULL;
DescriptorClassification kind = analyze_descriptor(type, name, &descr, 0);
assert(descr != NULL || kind == ABSENT || kind == GETSET_OVERRIDDEN);
if (type_get_version(type, LOAD_ATTR) == 0) {
goto fail;
}
switch(kind) {
case OVERRIDING:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_OVERRIDING_DESCRIPTOR);
@ -1057,6 +1061,9 @@ _Py_Specialize_StoreAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name)
}
PyObject *descr;
DescriptorClassification kind = analyze_descriptor(type, name, &descr, 1);
if (type_get_version(type, STORE_ATTR) == 0) {
goto fail;
}
switch(kind) {
case OVERRIDING:
SPECIALIZATION_FAIL(STORE_ATTR, SPEC_FAIL_ATTR_OVERRIDING_DESCRIPTOR);
@ -1183,6 +1190,9 @@ specialize_class_load_attr(PyObject *owner, _Py_CODEUNIT *instr,
PyObject *descr = NULL;
DescriptorClassification kind = 0;
kind = analyze_descriptor((PyTypeObject *)owner, name, &descr, 0);
if (type_get_version((PyTypeObject *)owner, LOAD_ATTR) == 0) {
return -1;
}
switch (kind) {
case METHOD:
case NON_DESCRIPTOR:
@ -1455,6 +1465,18 @@ function_get_version(PyObject *o, int opcode)
return version;
}
/* Returning 0 indicates a failure. */
static uint32_t
type_get_version(PyTypeObject *t, int opcode)
{
uint32_t version = t->tp_version_tag;
if (version == 0) {
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_OUT_OF_VERSIONS);
return 0;
}
return version;
}
void
_Py_Specialize_BinarySubscr(
PyObject *container, PyObject *sub, _Py_CODEUNIT *instr)
@ -1726,6 +1748,9 @@ specialize_class_call(PyObject *callable, _Py_CODEUNIT *instr, int nargs)
}
if (tp->tp_new == PyBaseObject_Type.tp_new) {
PyFunctionObject *init = get_init_for_simple_managed_python_class(tp);
if (type_get_version(tp, CALL) == 0) {
return -1;
}
if (init != NULL) {
if (((PyCodeObject *)init->func_code)->co_argcount != nargs+1) {
SPECIALIZATION_FAIL(CALL, SPEC_FAIL_WRONG_NUMBER_ARGUMENTS);
@ -2466,7 +2491,10 @@ _Py_Specialize_ToBool(PyObject *value, _Py_CODEUNIT *instr)
SPECIALIZATION_FAIL(TO_BOOL, SPEC_FAIL_OUT_OF_VERSIONS);
goto failure;
}
uint32_t version = Py_TYPE(value)->tp_version_tag;
uint32_t version = type_get_version(Py_TYPE(value), TO_BOOL);
if (version == 0) {
goto failure;
}
instr->op.code = TO_BOOL_ALWAYS_TRUE;
write_u32(cache->version, version);
assert(version);