Issue #27507: Check for integer overflow in bytearray.extend()

Patch by Xiang Zhang.

1 files changed, 11 insertions, 1 deletions

diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index b21acfb3f0..145863575f 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -2474,7 +2474,17 @@ bytearray_extend(PyByteArrayObject *self, PyObject *iterable_of_ints)
         Py_DECREF(item);
 
         if (len >= buf_size) {
-            buf_size = len + (len >> 1) + 1;
+            Py_ssize_t addition;
+            if (len == PY_SSIZE_T_MAX) {
+                Py_DECREF(it);
+                Py_DECREF(bytearray_obj);
+                return PyErr_NoMemory();
+            }
+            addition = len >> 1;
+            if (addition > PY_SSIZE_T_MAX - len - 1)
+                buf_size = PY_SSIZE_T_MAX;
+            else
+                buf_size = len + addition + 1;
             if (PyByteArray_Resize((PyObject *)bytearray_obj, buf_size) < 0) {
                 Py_DECREF(it);
                 Py_DECREF(bytearray_obj);