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gh-104614: Make Sure ob_type is Always Set Correctly by PyType_Ready() (gh-105122)

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When I added the relevant condition to type_ready_set_bases() in gh-103912, I had missed that the function also sets tp_base and ob_type (if necessary).  That led to problems for third-party static types.

We fix that here, by making those extra operations distinct and by adjusting the condition to be more specific.
This commit is contained in:
Eric Snow 2023-06-01 16:28:31 -06:00 • committed by GitHub
parent 3698fda06e
commit 146939306a
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GPG key ID: 4AEE18F83AFDEB23
4 changed files with 128 additions and 17 deletions
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60
Objects/typeobject.c
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@ -306,11 +306,14 @@ clear_tp_bases(PyTypeObject *self)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
if (_Py_IsMainInterpreter(_PyInterpreterState_GET())) {
if (self->tp_bases != NULL
&& PyTuple_GET_SIZE(self->tp_bases) > 0)
{
assert(_Py_IsImmortal(self->tp_bases));
_Py_ClearImmortal(self->tp_bases);
if (self->tp_bases != NULL) {
if (PyTuple_GET_SIZE(self->tp_bases) == 0) {
Py_CLEAR(self->tp_bases);
}
else {
assert(_Py_IsImmortal(self->tp_bases));
_Py_ClearImmortal(self->tp_bases);
}
}
}
return;
@ -352,11 +355,14 @@ clear_tp_mro(PyTypeObject *self)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
if (_Py_IsMainInterpreter(_PyInterpreterState_GET())) {
if (self->tp_mro != NULL
&& PyTuple_GET_SIZE(self->tp_mro) > 0)
{
assert(_Py_IsImmortal(self->tp_mro));
_Py_ClearImmortal(self->tp_mro);
if (self->tp_mro != NULL) {
if (PyTuple_GET_SIZE(self->tp_mro) == 0) {
Py_CLEAR(self->tp_mro);
}
else {
assert(_Py_IsImmortal(self->tp_mro));
_Py_ClearImmortal(self->tp_mro);
}
}
}
return;
@ -6996,12 +7002,8 @@ type_ready_pre_checks(PyTypeObject *type)
static int
type_ready_set_bases(PyTypeObject *type)
type_ready_set_base(PyTypeObject *type)
{
if (lookup_tp_bases(type) != NULL) {
return 0;
}
/* Initialize tp_base (defaults to BaseObject unless that's us) */
PyTypeObject *base = type->tp_base;
if (base == NULL && type != &PyBaseObject_Type) {
@ -7025,6 +7027,12 @@ type_ready_set_bases(PyTypeObject *type)
}
}
return 0;
}
static int
type_ready_set_type(PyTypeObject *type)
{
/* Initialize ob_type if NULL. This means extensions that want to be
compilable separately on Windows can call PyType_Ready() instead of
initializing the ob_type field of their type objects. */
@ -7032,11 +7040,25 @@ type_ready_set_bases(PyTypeObject *type)
NULL when type is &PyBaseObject_Type, and we know its ob_type is
not NULL (it's initialized to &PyType_Type). But coverity doesn't
know that. */
PyTypeObject *base = type->tp_base;
if (Py_IS_TYPE(type, NULL) && base != NULL) {
Py_SET_TYPE(type, Py_TYPE(base));
}
/* Initialize tp_bases */
return 0;
}
static int
type_ready_set_bases(PyTypeObject *type)
{
if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
if (!_Py_IsMainInterpreter(_PyInterpreterState_GET())) {
assert(lookup_tp_bases(type) != NULL);
return 0;
}
assert(lookup_tp_bases(type) == NULL);
}
PyObject *bases = lookup_tp_bases(type);
if (bases == NULL) {
PyTypeObject *base = type->tp_base;
@ -7446,6 +7468,12 @@ type_ready(PyTypeObject *type, int rerunbuiltin)
if (type_ready_set_dict(type) < 0) {
goto error;
}
if (type_ready_set_base(type) < 0) {
goto error;
}
if (type_ready_set_type(type) < 0) {
goto error;
}
if (type_ready_set_bases(type) < 0) {
goto error;
}