[Python-checkins] bpo-29587: _PyErr_ChainExceptions() checks exception (GH-19902)
Victor Stinner
webhook-mailer at python.org
Tue May 5 11:07:50 EDT 2020
https://github.com/python/cpython/commit/b0be6b3b94fbdf31b796adc19dc86a04a52b03e1
commit: b0be6b3b94fbdf31b796adc19dc86a04a52b03e1
branch: master
author: Victor Stinner <vstinner at python.org>
committer: GitHub <noreply at github.com>
date: 2020-05-05T17:07:41+02:00
summary:
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
files:
M Lib/test/test_generators.py
M Objects/exceptions.c
M Objects/genobject.c
M Python/errors.c
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 5824ecd7c37e8..e047801199680 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -342,9 +342,6 @@ def g():
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()
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index ca917b436c4bb..db5e3da12b00f 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -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;
}
diff --git a/Objects/genobject.c b/Objects/genobject.c
index b27fa929a2625..5b253edfdcd0f 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -512,15 +512,15 @@ _gen_throw(PyGenObject *gen, int close_on_genexit,
}
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);
diff --git a/Python/errors.c b/Python/errors.c
index 9e53d050416ff..f856a798eed1e 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -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);
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