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bpo-45385: Fix reference leak from descr_check #28719

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Merged
corona10 merged 1 commit into from
Oct 7, 2021
Merged

bpo-45385: Fix reference leak from descr_check #28719

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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2021-10-06-21-20-11.bpo-45385.CTUT8s.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fix reference leak from descr_check. Patch by Dong-hee Na.
76 changes: 37 additions & 39 deletions Objects/descrobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -72,22 +72,16 @@ wrapperdescr_repr(PyWrapperDescrObject *descr)
}

static int
descr_check(PyDescrObject *descr, PyObject *obj, PyObject **pres)
descr_check(PyDescrObject *descr, PyObject *obj)
{
if (obj == NULL) {
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Py_INCREF(descr);
*pres = (PyObject *)descr;
return 1;
}
if (!PyObject_TypeCheck(obj, descr->d_type)) {
PyErr_Format(PyExc_TypeError,
"descriptor '%V' for '%.100s' objects "
"doesn't apply to a '%.100s' object",
descr_name((PyDescrObject *)descr), "?",
descr->d_type->tp_name,
Py_TYPE(obj)->tp_name);
*pres = NULL;
return 1;
return -1;
}
return 0;
}
Expand Down Expand Up @@ -137,10 +131,12 @@ classmethod_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
static PyObject *
method_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
{
PyObject *res;

if (descr_check((PyDescrObject *)descr, obj, &res))
return res;
if (obj == NULL) {
return Py_NewRef(descr);
}
if (descr_check((PyDescrObject *)descr, obj) < 0) {
return NULL;
}
if (descr->d_method->ml_flags & METH_METHOD) {
if (PyType_Check(type)) {
return PyCMethod_New(descr->d_method, obj, NULL, descr->d_common.d_type);
Expand All @@ -159,10 +155,12 @@ method_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
static PyObject *
member_get(PyMemberDescrObject *descr, PyObject *obj, PyObject *type)
{
PyObject *res;

if (descr_check((PyDescrObject *)descr, obj, &res))
return res;
if (obj == NULL) {
return Py_NewRef(descr);
}
if (descr_check((PyDescrObject *)descr, obj) < 0) {
return NULL;
}

if (descr->d_member->flags & PY_AUDIT_READ) {
if (PySys_Audit("object.__getattr__", "Os",
Expand All @@ -177,10 +175,12 @@ member_get(PyMemberDescrObject *descr, PyObject *obj, PyObject *type)
static PyObject *
getset_get(PyGetSetDescrObject *descr, PyObject *obj, PyObject *type)
{
PyObject *res;

if (descr_check((PyDescrObject *)descr, obj, &res))
return res;
if (obj == NULL) {
return Py_NewRef(descr);
}
if (descr_check((PyDescrObject *)descr, obj) < 0) {
return NULL;
}
if (descr->d_getset->get != NULL)
return descr->d_getset->get(obj, descr->d_getset->closure);
PyErr_Format(PyExc_AttributeError,
Expand All @@ -193,16 +193,17 @@ getset_get(PyGetSetDescrObject *descr, PyObject *obj, PyObject *type)
static PyObject *
wrapperdescr_get(PyWrapperDescrObject *descr, PyObject *obj, PyObject *type)
{
PyObject *res;

if (descr_check((PyDescrObject *)descr, obj, &res))
return res;
if (obj == NULL) {
return Py_NewRef(descr);
}
if (descr_check((PyDescrObject *)descr, obj) < 0) {
return NULL;
}
return PyWrapper_New((PyObject *)descr, obj);
}

static int
descr_setcheck(PyDescrObject *descr, PyObject *obj, PyObject *value,

@Fidget-Spinner Fidget-Spinner Oct 6, 2021

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Wow, why did this (and the code below) change too? I don't think this was buggy, though the new code improves readability/makes it easier to understand.

I'm guessing for consistency reasons?

@vstinner vstinner Oct 6, 2021

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I asked @corona10 to mention compiler warnings in the commit message. I cannot see compiler warnings in https://bugs.python.org/issue45385, in the PR description, or in the commit message.

@corona10 corona10 Oct 6, 2021

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I'm guessing for consistency reasons?

Yes and it improve the readability :)

int *pres)
descr_setcheck(PyDescrObject *descr, PyObject *obj, PyObject *value)
{
assert(obj != NULL);
if (!PyObject_TypeCheck(obj, descr->d_type)) {
Expand All @@ -212,32 +213,30 @@ descr_setcheck(PyDescrObject *descr, PyObject *obj, PyObject *value,
descr_name(descr), "?",
descr->d_type->tp_name,
Py_TYPE(obj)->tp_name);
*pres = -1;
return 1;
return -1;
}
return 0;
}

static int
member_set(PyMemberDescrObject *descr, PyObject *obj, PyObject *value)
{
int res;

if (descr_setcheck((PyDescrObject *)descr, obj, value, &res))
return res;
if (descr_setcheck((PyDescrObject *)descr, obj, value) < 0) {
return -1;
}
return PyMember_SetOne((char *)obj, descr->d_member, value);
}

static int
getset_set(PyGetSetDescrObject *descr, PyObject *obj, PyObject *value)
{
int res;

if (descr_setcheck((PyDescrObject *)descr, obj, value, &res))
return res;
if (descr->d_getset->set != NULL)
if (descr_setcheck((PyDescrObject *)descr, obj, value) < 0) {
return -1;
}
if (descr->d_getset->set != NULL) {
return descr->d_getset->set(obj, value,
descr->d_getset->closure);
}
PyErr_Format(PyExc_AttributeError,
"attribute '%V' of '%.100s' objects is not writable",
descr_name((PyDescrObject *)descr), "?",
Expand All @@ -264,8 +263,7 @@ method_check_args(PyObject *func, PyObject *const *args, Py_ssize_t nargs, PyObj
return -1;
}
PyObject *self = args[0];
PyObject *dummy;
if (descr_check((PyDescrObject *)func, self, &dummy)) {
if (descr_check((PyDescrObject *)func, self) < 0) {
return -1;
}
if (kwnames && PyTuple_GET_SIZE(kwnames)) {
Expand Down