bpo-38913: Fix segfault in Py_BuildValue("(s#O)", ...) if entered with exception raised. (GH-18656)

1 files changed, 43 insertions, 0 deletions

diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index eb31a0e..23a27e3 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -5258,6 +5258,9 @@ meth_fastcall_keywords(PyObject* self, PyObject* const* args,
     return Py_BuildValue("NNN", _null_to_none(self), pyargs, pykwargs);
 }
 
+
+static PyObject *test_buildvalue_issue38913(PyObject *, PyObject *);
+
 static PyMethodDef TestMethods[] = {
     {"raise_exception",         raise_exception,                 METH_VARARGS},
     {"raise_memoryerror",       raise_memoryerror,               METH_NOARGS},
@@ -5322,6 +5325,7 @@ static PyMethodDef TestMethods[] = {
     {"getbuffer_with_null_view", getbuffer_with_null_view, METH_O},
     {"PyBuffer_SizeFromFormat",  test_PyBuffer_SizeFromFormat, METH_VARARGS},
     {"test_buildvalue_N",       test_buildvalue_N,               METH_NOARGS},
+    {"test_buildvalue_issue38913", test_buildvalue_issue38913,   METH_NOARGS},
     {"get_args", get_args, METH_VARARGS},
     {"get_kwargs", (PyCFunction)(void(*)(void))get_kwargs, METH_VARARGS|METH_KEYWORDS},
     {"getargs_tuple",           getargs_tuple,                   METH_VARARGS},
@@ -6791,3 +6795,42 @@ PyInit__testcapi(void)
     PyState_AddModule(m, &_testcapimodule);
     return m;
 }
+
+
+/* Test the C API exposed when PY_SSIZE_T_CLEAN is not defined */
+
+#undef Py_BuildValue
+PyAPI_FUNC(PyObject *) Py_BuildValue(const char *, ...);
+
+static PyObject *
+test_buildvalue_issue38913(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    PyObject *res;
+    const char str[] = "string";
+    const Py_UNICODE unicode[] = L"unicode";
+    PyErr_SetNone(PyExc_ZeroDivisionError);
+
+    res = Py_BuildValue("(s#O)", str, 1, Py_None);
+    assert(res == NULL);
+    if (!PyErr_ExceptionMatches(PyExc_ZeroDivisionError)) {
+        return NULL;
+    }
+    res = Py_BuildValue("(z#O)", str, 1, Py_None);
+    assert(res == NULL);
+    if (!PyErr_ExceptionMatches(PyExc_ZeroDivisionError)) {
+        return NULL;
+    }
+    res = Py_BuildValue("(y#O)", str, 1, Py_None);
+    assert(res == NULL);
+    if (!PyErr_ExceptionMatches(PyExc_ZeroDivisionError)) {
+        return NULL;
+    }
+    res = Py_BuildValue("(u#O)", unicode, 1, Py_None);
+    assert(res == NULL);
+    if (!PyErr_ExceptionMatches(PyExc_ZeroDivisionError)) {
+        return NULL;
+    }
+
+    PyErr_Clear();
+    Py_RETURN_NONE;
+}