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

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Merged
serhiy-storchaka merged 2 commits into from
Mar 2, 2020
+48 −3
Merged

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

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bpo-38913: Fix segfault in Py_BuildValue("(s#O)", ...) if entered wit…
serhiy-storchaka Feb 25, 2020
3f88dee
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serhiy-storchaka Feb 25, 2020
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/C API/2020-02-25-20-10-34.bpo-38913.siF1lS.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fixed segfault in ``Py_BuildValue()`` called with a format containing "#"
and undefined PY_SSIZE_T_CLEAN whwn an exception is set.
43 changes: 43 additions & 0 deletions Modules/_testcapimodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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},
Expand Down Expand Up @@ -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},
Expand Down Expand Up @@ -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;
}
6 changes: 3 additions & 3 deletions Python/modsupport.c
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Expand Up @@ -343,11 +343,11 @@ do_mkvalue(const char **p_format, va_list *p_va, int flags)
if (flags & FLAG_SIZE_T)
n = va_arg(*p_va, Py_ssize_t);
else {
n = va_arg(*p_va, int);
if (PyErr_WarnEx(PyExc_DeprecationWarning,
"PY_SSIZE_T_CLEAN will be required for '#' formats", 1)) {
return NULL;
}
n = va_arg(*p_va, int);
}
}
else
Expand Down Expand Up @@ -396,11 +396,11 @@ do_mkvalue(const char **p_format, va_list *p_va, int flags)
if (flags & FLAG_SIZE_T)
n = va_arg(*p_va, Py_ssize_t);
else {
n = va_arg(*p_va, int);
if (PyErr_WarnEx(PyExc_DeprecationWarning,
"PY_SSIZE_T_CLEAN will be required for '#' formats", 1)) {
return NULL;
}
n = va_arg(*p_va, int);
}
}
else
Expand Down Expand Up @@ -434,11 +434,11 @@ do_mkvalue(const char **p_format, va_list *p_va, int flags)
if (flags & FLAG_SIZE_T)
n = va_arg(*p_va, Py_ssize_t);
else {
n = va_arg(*p_va, int);
if (PyErr_WarnEx(PyExc_DeprecationWarning,
"PY_SSIZE_T_CLEAN will be required for '#' formats", 1)) {
return NULL;
}
n = va_arg(*p_va, int);
}
}
else
Expand Down