From b0331c94c2a210d50e43d99b249ec83ee165e70c Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 6 Nov 2017 16:45:19 -0800
Subject: [PATCH] bpo-31764: Prevent a crash in sqlite3.Cursor.close() in case
 the Cursor object is uninitialized (GH-3958) (#4303)

(cherry picked from commit edb13ae48c17210fa4b2d40a6833ca09db5c121b)
---
 Lib/sqlite3/test/regression.py                               | 3 +++
 .../next/Library/2017-10-11-22-18-04.bpo-31764.EMyIkK.rst    | 2 ++
 Modules/_sqlite/cursor.c                                     | 5 +++++
 3 files changed, 10 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2017-10-11-22-18-04.bpo-31764.EMyIkK.rst

diff --git a/Lib/sqlite3/test/regression.py b/Lib/sqlite3/test/regression.py
index 3ff9abd989..34cd233535 100644
--- a/Lib/sqlite3/test/regression.py
+++ b/Lib/sqlite3/test/regression.py
@@ -190,6 +190,9 @@ class RegressionTests(unittest.TestCase):
         cur = Cursor(con)
         with self.assertRaises(sqlite.ProgrammingError):
             cur.execute("select 4+5").fetchall()
+        with self.assertRaisesRegex(sqlite.ProgrammingError,
+                                    r'^Base Cursor\.__init__ not called\.$'):
+            cur.close()
 
     def CheckStrSubclass(self):
         """
diff --git a/Misc/NEWS.d/next/Library/2017-10-11-22-18-04.bpo-31764.EMyIkK.rst b/Misc/NEWS.d/next/Library/2017-10-11-22-18-04.bpo-31764.EMyIkK.rst
new file mode 100644
index 0000000000..a5a4ce548e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-10-11-22-18-04.bpo-31764.EMyIkK.rst
@@ -0,0 +1,2 @@
+Prevent a crash in ``sqlite3.Cursor.close()`` in case the ``Cursor`` object is
+uninitialized. Patch by Oren Milman.
diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
index b6257a0b9d..8237340947 100644
--- a/Modules/_sqlite/cursor.c
+++ b/Modules/_sqlite/cursor.c
@@ -916,6 +916,11 @@ PyObject* pysqlite_noop(pysqlite_Connection* self, PyObject* args)
 
 PyObject* pysqlite_cursor_close(pysqlite_Cursor* self, PyObject* args)
 {
+    if (!self->connection) {
+        PyErr_SetString(pysqlite_ProgrammingError,
+                        "Base Cursor.__init__ not called.");
+        return NULL;
+    }
     if (!pysqlite_check_thread(self->connection) || !pysqlite_check_connection(self->connection)) {
         return NULL;
     }
-- 
2.50.0