Issue #15989: Fix several occurrences of integer overflow

when result of PyInt_AsLong() or PyLong_AsLong() narrowed
to int without checks.

This is a backport of changesets 13e2e44db99d and 525407d89277.

1 files changed, 14 insertions, 0 deletions

diff --git a/Objects/intobject.c b/Objects/intobject.c
index 1ae8006c28..28182f93db 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -189,6 +189,20 @@ PyInt_AsLong(register PyObject *op)
     return val;
 }
 
+int
+_PyInt_AsInt(PyObject *obj)
+{
+    long result = PyInt_AsLong(obj);
+    if (result == -1 && PyErr_Occurred())
+        return -1;
+    if (result > INT_MAX || result < INT_MIN) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "Python int too large to convert to C int");
+        return -1;
+    }
+    return (int)result;
+}
+
 Py_ssize_t
 PyInt_AsSsize_t(register PyObject *op)
 {