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

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Merged
markshannon merged 8 commits into from
Sep 5, 2023
Merged

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

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1f7d840
Reject non local events in sys.monitoring.set_local_events()
markshannon Aug 13, 2023
b9e453d
Skip instrumenting code objects if that code object cannot produce lo…
markshannon Aug 13, 2023
ab435bc
Add additional safeguard
markshannon Aug 13, 2023
5659905
Add news
markshannon Aug 13, 2023
9015dd0
Address review comments
markshannon Aug 28, 2023
29c9065
Update Python/instrumentation.c
markshannon Sep 1, 2023
896ffd4
Update Python/instrumentation.c
markshannon Sep 1, 2023
c6b2c1a
Add missing return
markshannon Sep 4, 2023
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Address review comments
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@markshannon
markshannon committed Aug 28, 2023
commit 9015dd07c28ef28b06571caeaad5707230705543
3 changes: 1 addition & 2 deletions Include/cpython/code.h
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Expand Up @@ -15,12 +15,11 @@ extern "C" {
/* Count of all monitoring events */
#define _PY_MONITORING_EVENTS 17

/* Table of which tools are active for each monitored event. */
/* Tables of which tools are active for each monitored event. */
typedef struct _Py_LocalMonitors {
uint8_t tools[_PY_MONITORING_LOCAL_EVENTS];
} _Py_LocalMonitors;

/* Table of which tools are active for each monitored event. */
typedef struct _Py_GlobalMonitors {
uint8_t tools[_PY_MONITORING_UNGROUPED_EVENTS];
} _Py_GlobalMonitors;
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2 changes: 1 addition & 1 deletion Misc/NEWS.d/next/Core and Builtins/2023-08-13-17-18-22.gh-issue-108390.TkBccC.rst
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@@ -1,4 +1,4 @@
Raise an exception when setting a non-local event (RAISE EXCEPTION_HANDLED,
Raise an exception when setting a non-local event (``RAISE``, ``EXCEPTION_HANDLED``,
etc.) in ``sys.monitoring.set_local_events``.

Fixes crash when tracing in recursive calls to Python classes.
27 changes: 14 additions & 13 deletions Python/ceval.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1968,29 +1968,30 @@ do_monitor_exc(PyThreadState *tstate, _PyInterpreterFrame *frame,
return err;
}

static inline int
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 (tstate->interp->monitors.tools[PY_MONITORING_EVENT_RAISE] == 0) {
if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_RAISE)) {
return;
}
do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_RAISE);
Expand All @@ -2000,7 +2001,7 @@ static void
monitor_reraise(PyThreadState *tstate, _PyInterpreterFrame *frame,
_Py_CODEUNIT *instr)
{
if (tstate->interp->monitors.tools[PY_MONITORING_EVENT_RERAISE] == 0) {
if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_RERAISE)) {
return;
}
do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_RERAISE);
Expand All @@ -2021,7 +2022,7 @@ monitor_unwind(PyThreadState *tstate,
_PyInterpreterFrame *frame,
_Py_CODEUNIT *instr)
{
if (tstate->interp->monitors.tools[PY_MONITORING_EVENT_PY_UNWIND] == 0) {
if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_PY_UNWIND)) {
return;
}
do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_PY_UNWIND);
Expand All @@ -2033,7 +2034,7 @@ monitor_handled(PyThreadState *tstate,
_PyInterpreterFrame *frame,
_Py_CODEUNIT *instr, PyObject *exc)
{
if (tstate->interp->monitors.tools[PY_MONITORING_EVENT_EXCEPTION_HANDLED] == 0) {
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);
Expand All @@ -2044,7 +2045,7 @@ monitor_throw(PyThreadState *tstate,
_PyInterpreterFrame *frame,
_Py_CODEUNIT *instr)
{
if (tstate->interp->monitors.tools[PY_MONITORING_EVENT_PY_THROW] == 0) {
if (no_tools_for_global_event(tstate, PY_MONITORING_EVENT_PY_THROW)) {
return;
}
do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_PY_THROW);
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15 changes: 13 additions & 2 deletions Python/instrumentation.c
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Expand Up @@ -169,6 +169,11 @@ monitors_and(_Py_LocalMonitors a, _Py_LocalMonitors b)
}
#endif

/* The union of the *local* events in a and b.
* Global events like RAISE are ignored.
* Used for instrumentation, as only local
* events get instrumented.
*/
static inline _Py_LocalMonitors
local_union(_Py_GlobalMonitors a, _Py_LocalMonitors b)
{
Expand Down Expand Up @@ -1554,6 +1559,12 @@ _Py_Instrument(PyCodeObject *code, PyInterpreterState *interp)
return 0;
}
int code_len = (int)Py_SIZE(code);
/* code->_co_firsttraceable >= code_len indicates
* that no instrumentation can be inserted.
* Exit early to avoid creating instuementation
* data for potential statically allocated code
* objects.
* See https://github.com/python/cpython/issues/108390 */
if (code->_co_firsttraceable >= code_len) {
return 0;
}
Expand Down Expand Up @@ -1710,9 +1721,9 @@ set_events(_Py_GlobalMonitors *m, int tool_id, _PyMonitoringEventSet events)
assert(0 <= tool_id && tool_id < PY_MONITORING_TOOL_IDS);
for (int e = 0; e < _PY_MONITORING_UNGROUPED_EVENTS; e++) {
uint8_t *tools = &m->tools[e];
int val = (events >> e) & 1;
int active = (events >> e) & 1;
*tools &= ~(1 << tool_id);
*tools |= (val << tool_id);
*tools |= (active << tool_id);
}
}

Expand Down