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/Python/ast.c b/Python/ast.c
index a6bb1b7..4d874af 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -3200,6 +3200,9 @@
buf = (char *)s;
u = NULL;
} else {
+ /* check for integer overflow */
+ if (len > PY_SIZE_MAX / 4)
+ return NULL;
/* "\XX" may become "\u005c\uHHLL" (12 bytes) */
u = PyString_FromStringAndSize((char *)NULL, len * 4);
if (u == NULL)