Merge in release25-maint r60793:
Added checks for integer overflows, contributed by Google. Some are
only available if asserts are left in the code, in cases where they
can't be triggered from Python code.
diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
index 2f2b35e..efbd566 100644
--- a/Objects/obmalloc.c
+++ b/Objects/obmalloc.c
@@ -526,9 +526,9 @@
numarenas = maxarenas ? maxarenas << 1 : INITIAL_ARENA_OBJECTS;
if (numarenas <= maxarenas)
return NULL; /* overflow */
- nbytes = numarenas * sizeof(*arenas);
- if (nbytes / sizeof(*arenas) != numarenas)
+ if (numarenas > PY_SIZE_MAX / sizeof(*arenas))
return NULL; /* overflow */
+ nbytes = numarenas * sizeof(*arenas);
arenaobj = (struct arena_object *)realloc(arenas, nbytes);
if (arenaobj == NULL)
return NULL;