bpo-36856: Handle possible overflow in faulthandler_stack_overflow (GH-13205)
diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index d45b866..63a9b91 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -1121,13 +1121,26 @@
{
size_t depth, size;
uintptr_t sp = (uintptr_t)&depth;
- uintptr_t stop;
+ uintptr_t stop, lower_limit, upper_limit;
faulthandler_suppress_crash_report();
depth = 0;
- stop = stack_overflow(sp - STACK_OVERFLOW_MAX_SIZE,
- sp + STACK_OVERFLOW_MAX_SIZE,
- &depth);
+
+ if (STACK_OVERFLOW_MAX_SIZE <= sp) {
+ lower_limit = sp - STACK_OVERFLOW_MAX_SIZE;
+ }
+ else {
+ lower_limit = 0;
+ }
+
+ if (UINTPTR_MAX - STACK_OVERFLOW_MAX_SIZE >= sp) {
+ upper_limit = sp + STACK_OVERFLOW_MAX_SIZE;
+ }
+ else {
+ upper_limit = UINTPTR_MAX;
+ }
+
+ stop = stack_overflow(lower_limit, upper_limit, &depth);
if (sp < stop)
size = stop - sp;
else