GH-108390: Prevent non-local events being set with `sys.monitoring.set_local_events()` (GH-108420)

1 files changed, 17 insertions, 15 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index 6f90d8e..b02bf60 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1978,28 +1978,30 @@ do_monitor_exc(PyThreadState *tstate, _PyInterpreterFrame *frame,
     return err;
 }
 
-static inline int
-no_tools_for_event(PyThreadState *tstate, _PyInterpreterFrame *frame, int event)
+static inline bool
+no_tools_for_global_event(PyThreadState *tstate, int event)
 {
+    return tstate->interp->monitors.tools[event] == 0;
+}
+
+static inline bool
+no_tools_for_local_event(PyThreadState *tstate, _PyInterpreterFrame *frame, int event)
+{
+    assert(event < _PY_MONITORING_LOCAL_EVENTS);
     _PyCoMonitoringData *data = _PyFrame_GetCode(frame)->_co_monitoring;
     if (data) {
-        if (data->active_monitors.tools[event] == 0) {
-            return 1;
-        }
+        return data->active_monitors.tools[event] == 0;
     }
     else {
-        if (tstate->interp->monitors.tools[event] == 0) {
-            return 1;
-        }
+        return no_tools_for_global_event(tstate, event);
     }
-    return 0;
 }
 
 static void
 monitor_raise(PyThreadState *tstate, _PyInterpreterFrame *frame,
               _Py_CODEUNIT *instr)
 {
-    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_RAISE)) {
+    if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_RAISE)) {
         return;
     }
     do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_RAISE);
@@ -2009,7 +2011,7 @@ static void
 monitor_reraise(PyThreadState *tstate, _PyInterpreterFrame *frame,
               _Py_CODEUNIT *instr)
 {
-    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_RERAISE)) {
+    if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_RERAISE)) {
         return;
     }
     do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_RERAISE);
@@ -2019,7 +2021,7 @@ static int
 monitor_stop_iteration(PyThreadState *tstate, _PyInterpreterFrame *frame,
                        _Py_CODEUNIT *instr)
 {
-    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_STOP_ITERATION)) {
+    if (no_tools_for_local_event(tstate, frame, PY_MONITORING_EVENT_STOP_ITERATION)) {
         return 0;
     }
     return do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_STOP_ITERATION);
@@ -2030,7 +2032,7 @@ monitor_unwind(PyThreadState *tstate,
                _PyInterpreterFrame *frame,
                _Py_CODEUNIT *instr)
 {
-    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_PY_UNWIND)) {
+    if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_PY_UNWIND)) {
         return;
     }
     do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_PY_UNWIND);
@@ -2042,7 +2044,7 @@ monitor_handled(PyThreadState *tstate,
                 _PyInterpreterFrame *frame,
                 _Py_CODEUNIT *instr, PyObject *exc)
 {
-    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_EXCEPTION_HANDLED)) {
+    if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_EXCEPTION_HANDLED)) {
         return 0;
     }
     return _Py_call_instrumentation_arg(tstate, PY_MONITORING_EVENT_EXCEPTION_HANDLED, frame, instr, exc);
@@ -2053,7 +2055,7 @@ monitor_throw(PyThreadState *tstate,
               _PyInterpreterFrame *frame,
               _Py_CODEUNIT *instr)
 {
-    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_PY_THROW)) {
+    if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_PY_THROW)) {
         return;
     }
     do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_PY_THROW);