Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(revision 74738)
+++ Modules/posixmodule.c	(working copy)
@@ -1933,14 +1933,26 @@
 posix_lchown(PyObject *self, PyObject *args)
 {
 	char *path = NULL;
-	int uid, gid;
+	long uid_arg, gid_arg;
+	uid_t uid;
+	gid_t gid;
 	int res;
 	if (!PyArg_ParseTuple(args, "etii:lchown",
 	                      Py_FileSystemDefaultEncoding, &path,
-	                      &uid, &gid))
+	                      &uid_arg, &gid_arg))
 		return NULL;
+	uid = uid_arg;
+	if (uid != uid_arg) {
+		PyErr_SetString(PyExc_OverflowError, "user id too big");
+		return NULL;
+	}
+	gid = gid_arg;
+	if (gid != gid_arg) {
+		PyErr_SetString(PyExc_OverflowError, "group id too big");
+		return NULL;
+	}
 	Py_BEGIN_ALLOW_THREADS
-	res = lchown(path, (uid_t) uid, (gid_t) gid);
+	res = lchown(path, uid, gid);
 	Py_END_ALLOW_THREADS
 	if (res < 0)
 		return posix_error_with_allocated_filename(path);