bpo-31746: Fixed Segfaults in the sqlite module when uninitialized.

Lib/sqlite3/test/regression.py

@@ -414,6 +414,33 @@ def test_return_empty_bytestring(self):
  val = cur.fetchone()[0]
  self.assertEqual(val, b'')
 
+ def test_uninitialized_isolation_level(self):
+ """
+ Previously trying to get the isolation level of an uninitialized Connection
+ caused a segfault, now it should just return None.
+ """
+ conn = sqlite.Connection.__new__(sqlite.Connection)
+ with self.assertRaises(sqlite.ProgrammingError):
+ conn.isolation_level
+
+ def test_cursor_invalid_isolation_level(self):
+ """
+ When trying to call conn.cursor() when conn is a Connection object that
+ was not initialized properly, it caused a segfault. Now it should raise
+ a ProgrammingError.
+ """
+ conn = sqlite.Connection.__new__(sqlite.Connection)
+ self.assertRaises(ValueError, conn.__init__, '', isolation_level='invalid isolation level')
+ self.assertRaises(sqlite.ProgrammingError, conn.cursor)
+
+
+ def test_close_invalid_connection(self):
+ """
+ Trying to call close() on a connection which was not initialized properly,
+ it caused a segfault. Now it should raise a ProgrammingError.
+ """
+ conn = sqlite.Connection.__new__(sqlite.Connection)
+ self.assertRaises(sqlite.ProgrammingError, conn.close)
 
 def suite():
  tests = [

Modules/_sqlite/connection.c

@@ -118,11 +118,15 @@ pysqlite_connection_init(pysqlite_Connection *self, PyObject *args,
  if (!isolation_level) {
  isolation_level = PyUnicode_FromString("");
  if (!isolation_level) {
+ PyErr_SetString(pysqlite_ProgrammingError, "Isolation level could not be set.");
  return -1;
  }
  } else {
  Py_INCREF(isolation_level);
  }
+
+ self->initialized = 1;
+
  Py_CLEAR(self->isolation_level);
  if (pysqlite_connection_set_isolation_level(self, isolation_level, NULL) < 0) {
  Py_DECREF(isolation_level);
@@ -250,8 +254,19 @@ pysqlite_connection_dealloc(pysqlite_Connection *self)
  */
 int pysqlite_connection_register_cursor(pysqlite_Connection* connection, PyObject* cursor)
 {
+ if (!connection || !connection->cursors) {
+ PyErr_Format(pysqlite_ProgrammingError,
+ "Base Connection.__init__ not called.");
+ goto error;
+ }
  PyObject* weakref;
 
+ if (!connection->cursors) {
+ PyErr_SetString(pysqlite_ProgrammingError,
+ "Base Connection.__init__ not called.");
+ goto error;
+ }
+
  weakref = PyWeakref_NewRef((PyObject*)cursor, NULL);
  if (!weakref) {
  goto error;
@@ -281,6 +296,11 @@ static PyObject *
 pysqlite_connection_cursor_impl(pysqlite_Connection *self, PyObject *factory)
 /*[clinic end generated code: output=562432a9e6af2aa1 input=4127345aa091b650]*/
 {
+ if (self == NULL) {
+ return NULL;
+ }
+
+ static char *kwlist[] = {"factory", NULL};
  PyObject* cursor;
 
  if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
@@ -323,6 +343,12 @@ pysqlite_connection_close_impl(pysqlite_Connection *self)
 /*[clinic end generated code: output=a546a0da212c9b97 input=3d58064bbffaa3d3]*/
 {
  int rc;
+
+ if (!self->statements) {
+ PyErr_SetString(pysqlite_ProgrammingError,
+ "Base Connection.__init__ not called.");
+ return NULL;
+ }
 
  if (!pysqlite_check_thread(self)) {
  return NULL;
@@ -1225,6 +1251,11 @@ int pysqlite_check_thread(pysqlite_Connection* self)
 
 static PyObject* pysqlite_connection_get_isolation_level(pysqlite_Connection* self, void* unused)
 {
+ if (!self || !self->isolation_level) {
+ PyErr_Format(pysqlite_ProgrammingError,
+ "Object is null or isolation_level is uninitialized.");
+ return 0;
+ }
  return Py_NewRef(self->isolation_level);
 }