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gh-105375: Harden pyexpat initialisation #105606

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Merged
merged 5 commits into from
Jun 11, 2023
Merged

gh-105375: Harden pyexpat initialisation #105606

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d6cf426
gh-105605: Harden pyexpat initialisation
erlend-aasland Jun 9, 2023
cb1effb
Merge branch 'main' into improve-pyexpat-error-handling
erlend-aasland Jun 9, 2023
143c3e3
=> PyModule_AddObjectREF
erlend-aasland Jun 9, 2023
9c21ec7
Merge branch 'main' into improve-pyexpat-error-handling
erlend-aasland Jun 11, 2023
5fd45cd
Add comment about borrowed ref
erlend-aasland Jun 11, 2023
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3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2023-06-09-23-00-13.gh-issue-105605.YuwqxY.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Harden :mod:`pyexpat` error handling during module initialisation to prevent
exceptions from possibly being overwritten, and objects from being
dereferenced twice.
18 changes: 11 additions & 7 deletions Modules/pyexpat.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1775,14 +1775,18 @@ add_error(PyObject *errors_module, PyObject *codes_dict,
static int
add_errors_module(PyObject *mod)
{
// add_submodule() returns a borrowed ref.
PyObject *errors_module = add_submodule(mod, MODULE_NAME ".errors");
if (errors_module == NULL) {
return -1;
}

PyObject *codes_dict = PyDict_New();
if (codes_dict == NULL) {
return -1;
}
PyObject *rev_codes_dict = PyDict_New();
if (codes_dict == NULL || rev_codes_dict == NULL) {
if (rev_codes_dict == NULL) {
goto error;
}

Expand All @@ -1803,17 +1807,17 @@ add_errors_module(PyObject *mod)
goto error;
}

if (PyModule_AddObject(errors_module, "codes", Py_NewRef(codes_dict)) < 0) {
Py_DECREF(codes_dict);
int rc = PyModule_AddObjectRef(errors_module, "codes", codes_dict);
Py_CLEAR(codes_dict);
if (rc < 0) {
goto error;
}
Py_CLEAR(codes_dict);

if (PyModule_AddObject(errors_module, "messages", Py_NewRef(rev_codes_dict)) < 0) {
Py_DECREF(rev_codes_dict);
rc = PyModule_AddObjectRef(errors_module, "messages", rev_codes_dict);
Py_CLEAR(rev_codes_dict);
if (rc < 0) {
goto error;
}
Py_CLEAR(rev_codes_dict);

return 0;

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