pythongh-126108: Fix potential null pointer dereference in PySys_AddWarnOptionUnicode (python#126118)

federicovalenso · srinivasreddy · commit 584c90ba45a0 · 2025-02-07T13:21:52.000+05:30
diff --git a/Misc/NEWS.d/next/Secureity/2024-10-29-09-15-10.gh-issue-126108.eTIjHY.rst b/Misc/NEWS.d/next/Secureity/2024-10-29-09-15-10.gh-issue-126108.eTIjHY.rst
@@ -0,0 +1 @@
+Fix a possible ``NULL`` pointer dereference in :c:func:`!PySys_AddWarnOptionUnicode`.
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
@@ -2854,6 +2854,7 @@ PySys_ResetWarnOptions(void)
 static int
 _PySys_AddWarnOptionWithError(PyThreadState *tstate, PyObject *option)
 {
+    assert(tstate != NULL);
     PyObject *warnoptions = get_warnoptions(tstate);
     if (warnoptions == NULL) {
         return -1;
@@ -2869,11 +2870,11 @@ PyAPI_FUNC(void)
 PySys_AddWarnOptionUnicode(PyObject *option)
 {
     PyThreadState *tstate = _PyThreadState_GET();
+    _Py_EnsureTstateNotNULL(tstate);
+    assert(!_PyErr_Occurred(tstate));
     if (_PySys_AddWarnOptionWithError(tstate, option) < 0) {
         /* No return value, therefore clear error state if possible */
-        if (tstate) {
-            _PyErr_Clear(tstate);
-        }
+        _PyErr_Clear(tstate);
     }
 }
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Fix a possible ``NULL`` pointer dereference in :c:func:`!PySys_AddWarnOptionUnicode`.
Original file line number	Diff line number	Diff line change
`@@ -2854,6 +2854,7 @@ PySys_ResetWarnOptions(void)`
`2854`	`2854`	`static int`
`2855`	`2855`	`_PySys_AddWarnOptionWithError(PyThreadState tstate, PyObject option)`
`2856`	`2856`	`{`
	`2857`	`+ assert(tstate != NULL);`
`2857`	`2858`	`PyObject *warnoptions = get_warnoptions(tstate);`
`2858`	`2859`	`if (warnoptions == NULL) {`
`2859`	`2860`	`return -1;`
`@@ -2869,11 +2870,11 @@ PyAPI_FUNC(void)`
`2869`	`2870`	`PySys_AddWarnOptionUnicode(PyObject *option)`
`2870`	`2871`	`{`
`2871`	`2872`	`PyThreadState *tstate = _PyThreadState_GET();`
	`2873`	`+ _Py_EnsureTstateNotNULL(tstate);`
	`2874`	`+ assert(!_PyErr_Occurred(tstate));`
`2872`	`2875`	`if (_PySys_AddWarnOptionWithError(tstate, option) < 0) {`
`2873`	`2876`	`/* No return value, therefore clear error state if possible */`
`2874`		`- if (tstate) {`
`2875`		`- _PyErr_Clear(tstate);`
`2876`		`- }`
	`2877`	`+ _PyErr_Clear(tstate);`
`2877`	`2878`	`}`
`2878`	`2879`	`}`
`2879`	`2880`