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[3.8] bpo-38643: Raise SystemError instead of crashing when PyNumber_ToBase is called with invalid base. (GH-18863). #18954

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Merged
serhiy-storchaka merged 1 commit into from
Mar 12, 2020
Merged

[3.8] bpo-38643: Raise SystemError instead of crashing when PyNumber_ToBase is called with invalid base. (GH-18863). #18954

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14 changes: 14 additions & 0 deletions Lib/test/test_capi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -473,6 +473,20 @@ def test_c_subclass_of_heap_ctype_with_del_modifying_dunder_class_only_decrefs_o
# Test that subtype_dealloc decref the newly assigned __class__ only once
self.assertEqual(new_type_refcnt, sys.getrefcount(_testcapi.HeapCTypeSubclass))

def test_pynumber_tobase(self):
from _testcapi import pynumber_tobase
self.assertEqual(pynumber_tobase(123, 2), '0b1111011')
self.assertEqual(pynumber_tobase(123, 8), '0o173')
self.assertEqual(pynumber_tobase(123, 10), '123')
self.assertEqual(pynumber_tobase(123, 16), '0x7b')
self.assertEqual(pynumber_tobase(-123, 2), '-0b1111011')
self.assertEqual(pynumber_tobase(-123, 8), '-0o173')
self.assertEqual(pynumber_tobase(-123, 10), '-123')
self.assertEqual(pynumber_tobase(-123, 16), '-0x7b')
self.assertRaises(TypeError, pynumber_tobase, 123.0, 10)
self.assertRaises(TypeError, pynumber_tobase, '123', 10)
self.assertRaises(SystemError, pynumber_tobase, 123, 0)


class TestPendingCalls(unittest.TestCase):

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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/C API/2020-03-08-22-56-22.bpo-38643.k2ixx6.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
:c:func:`PyNumber_ToBase` now raises a :exc:`SystemError` instead of
crashing when called with invalid base.
14 changes: 14 additions & 0 deletions Modules/_testcapimodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5063,6 +5063,19 @@ test_write_unraisable_exc(PyObject *self, PyObject *args)
}


static PyObject*
pynumber_tobase(PyObject *module, PyObject *args)
{
PyObject *obj;
int base;
if (!PyArg_ParseTuple(args, "Oi:pynumber_tobase",
&obj, &base)) {
return NULL;
}
return PyNumber_ToBase(obj, base);
}


static PyObject *test_buildvalue_issue38913(PyObject *, PyObject *);

static PyMethodDef TestMethods[] = {
Expand Down Expand Up @@ -5309,6 +5322,7 @@ static PyMethodDef TestMethods[] = {
{"negative_refcount", negative_refcount, METH_NOARGS},
#endif
{"write_unraisable_exc", test_write_unraisable_exc, METH_VARARGS},
{"pynumber_tobase", pynumber_tobase, METH_VARARGS},
{NULL, NULL} /* sentinel */
};

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15 changes: 6 additions & 9 deletions Objects/abstract.c
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Expand Up @@ -1509,18 +1509,15 @@ PyNumber_Float(PyObject *o)
PyObject *
PyNumber_ToBase(PyObject *n, int base)
{
PyObject *res = NULL;
if (!(base == 2 || base == 8 || base == 10 || base == 16)) {
PyErr_SetString(PyExc_SystemError,
"PyNumber_ToBase: base must be 2, 8, 10 or 16");
return NULL;
}
PyObject *index = PyNumber_Index(n);

if (!index)
return NULL;
if (PyLong_Check(index))
res = _PyLong_Format(index, base);
else
/* It should not be possible to get here, as
PyNumber_Index already has a check for the same
condition */
PyErr_SetString(PyExc_ValueError, "PyNumber_ToBase: index not int");
PyObject *res = _PyLong_Format(index, base);
Py_DECREF(index);
return res;
}
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