bpo-29587: _PyErr_ChainExceptions() checks exception (GH-19902)

_PyErr_ChainExceptions() now ensures that the first parameter is an
exception type, as done by _PyErr_SetObject().

* The following function now check PyExceptionInstance_Check() in an
  assertion using a new _PyBaseExceptionObject_cast() helper
  function:

  * PyException_GetTraceback(), PyException_SetTraceback()
  * PyException_GetCause(), PyException_SetCause()
  * PyException_GetContext(), PyException_SetContext()

* PyExceptionClass_Name() now checks PyExceptionClass_Check() with an
  assertion.

* Remove XXX comment and add gi_exc_state variable to _gen_throw().

* Remove comment from test_generators
This commit is contained in:
Victor Stinner 2020-05-05 17:07:41 +02:00 committed by GitHub
parent 4e30ed3af0
commit b0be6b3b94
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 45 additions and 24 deletions

View File

@ -342,9 +342,6 @@ class GeneratorThrowTest(unittest.TestCase):
try:
yield
except Exception:
# Without the `gi_exc_state.exc_type != Py_None` in
# _gen_throw(), this line was causing a crash ("Segmentation
# fault (core dumped)") on e.g. Fedora 32.
raise RuntimeError
gen = g()

View File

@ -304,22 +304,33 @@ static PyGetSetDef BaseException_getset[] = {
};
static inline PyBaseExceptionObject*
_PyBaseExceptionObject_cast(PyObject *exc)
{
assert(PyExceptionInstance_Check(exc));
return (PyBaseExceptionObject *)exc;
}
PyObject *
PyException_GetTraceback(PyObject *self) {
PyBaseExceptionObject *base_self = (PyBaseExceptionObject *)self;
PyException_GetTraceback(PyObject *self)
{
PyBaseExceptionObject *base_self = _PyBaseExceptionObject_cast(self);
Py_XINCREF(base_self->traceback);
return base_self->traceback;
}
int
PyException_SetTraceback(PyObject *self, PyObject *tb) {
return BaseException_set_tb((PyBaseExceptionObject *)self, tb, NULL);
PyException_SetTraceback(PyObject *self, PyObject *tb)
{
return BaseException_set_tb(_PyBaseExceptionObject_cast(self), tb, NULL);
}
PyObject *
PyException_GetCause(PyObject *self) {
PyObject *cause = ((PyBaseExceptionObject *)self)->cause;
PyException_GetCause(PyObject *self)
{
PyObject *cause = _PyBaseExceptionObject_cast(self)->cause;
Py_XINCREF(cause);
return cause;
}
@ -328,13 +339,15 @@ PyException_GetCause(PyObject *self) {
void
PyException_SetCause(PyObject *self, PyObject *cause)
{
((PyBaseExceptionObject *)self)->suppress_context = 1;
Py_XSETREF(((PyBaseExceptionObject *)self)->cause, cause);
PyBaseExceptionObject *base_self = _PyBaseExceptionObject_cast(self);
base_self->suppress_context = 1;
Py_XSETREF(base_self->cause, cause);
}
PyObject *
PyException_GetContext(PyObject *self) {
PyObject *context = ((PyBaseExceptionObject *)self)->context;
PyException_GetContext(PyObject *self)
{
PyObject *context = _PyBaseExceptionObject_cast(self)->context;
Py_XINCREF(context);
return context;
}
@ -343,7 +356,7 @@ PyException_GetContext(PyObject *self) {
void
PyException_SetContext(PyObject *self, PyObject *context)
{
Py_XSETREF(((PyBaseExceptionObject *)self)->context, context);
Py_XSETREF(_PyBaseExceptionObject_cast(self)->context, context);
}
#undef PyExceptionClass_Name
@ -351,6 +364,7 @@ PyException_SetContext(PyObject *self, PyObject *context)
const char *
PyExceptionClass_Name(PyObject *ob)
{
assert(PyExceptionClass_Check(ob));
return ((PyTypeObject*)ob)->tp_name;
}

View File

@ -512,15 +512,15 @@ throw_here:
}
PyErr_Restore(typ, val, tb);
/* XXX It seems like we shouldn't have to check not equal to Py_None
here because exc_type should only ever be a class. But not including
this check was causing crashes on certain tests e.g. on Fedora. */
if (gen->gi_exc_state.exc_type && gen->gi_exc_state.exc_type != Py_None) {
Py_INCREF(gen->gi_exc_state.exc_type);
Py_XINCREF(gen->gi_exc_state.exc_value);
Py_XINCREF(gen->gi_exc_state.exc_traceback);
_PyErr_ChainExceptions(gen->gi_exc_state.exc_type,
gen->gi_exc_state.exc_value, gen->gi_exc_state.exc_traceback);
_PyErr_StackItem *gi_exc_state = &gen->gi_exc_state;
if (gi_exc_state->exc_type != NULL && gi_exc_state->exc_type != Py_None) {
Py_INCREF(gi_exc_state->exc_type);
Py_XINCREF(gi_exc_state->exc_value);
Py_XINCREF(gi_exc_state->exc_traceback);
_PyErr_ChainExceptions(gi_exc_state->exc_type,
gi_exc_state->exc_value,
gi_exc_state->exc_traceback);
}
return gen_send_ex(gen, Py_None, 1, 0);

View File

@ -107,7 +107,8 @@ _PyErr_SetObject(PyThreadState *tstate, PyObject *exception, PyObject *value)
if (exception != NULL &&
!PyExceptionClass_Check(exception)) {
_PyErr_Format(tstate, PyExc_SystemError,
"exception %R not a BaseException subclass",
"_PyErr_SetObject: "
"exception %R is not a BaseException subclass",
exception);
return;
}
@ -484,6 +485,15 @@ _PyErr_ChainExceptions(PyObject *exc, PyObject *val, PyObject *tb)
return;
PyThreadState *tstate = _PyThreadState_GET();
if (!PyExceptionClass_Check(exc)) {
_PyErr_Format(tstate, PyExc_SystemError,
"_PyErr_ChainExceptions: "
"exception %R is not a BaseException subclass",
exc);
return;
}
if (_PyErr_Occurred(tstate)) {
PyObject *exc2, *val2, *tb2;
_PyErr_Fetch(tstate, &exc2, &val2, &tb2);