Creating an encrypted volume type without a cipher accepted but will fail to create an encrypted volume

There appears to be no validation done by c-api when creating an encrypted volume type that leads to volume creation failures later when used:

$ openstack volume type create --encryption-provider luks --encryption-key-size 256 --encryption-control-location front-end luks
$ openstack volume type show luks
+--------------------+--------------------------------------+
| Field | Value |
+--------------------+--------------------------------------+
| access_project_ids | None |
| description | None |
| id | 81de0e95-4128-4fd2-adbb-add832c6683c |
| is_public | True |
| name | luks |
| properties | |
| qos_specs_id | None |
+--------------------+--------------------------------------+
$ openstack volume create --size 1 --type luks luks

c-vol failure:

2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server [req-8224c046-d157-44f5-829b-e376ddf19743 2fcb35dd719f47b9bafd151dd122bbfb 3f2eb42c05bd4d0084648cb2f873a562 - default default] Exception during message handling: AttributeError: 'NoneType' object has no attribute 'split'
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server Traceback (most recent call last):
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 166, in _process_incoming
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server res = self.dispatcher.dispatch(message)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 220, in dispatch
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server return self._do_dispatch(endpoint, method, ctxt, args)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 190, in _do_dispatch
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server result = func(ctxt, **new_args)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "<string>", line 2, in create_volume
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/objects/cleanable.py", line 207, in wrapper
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server result = f(*args, **kwargs)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/manager.py", line 690, in create_volume
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server _run_flow()
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/manager.py", line 682, in _run_flow
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server flow_engine.run()
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/taskflow/engines/action_engine/engine.py", line 247, in run
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server for _state in self.run_iter(timeout=timeout):
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/taskflow/engines/action_engine/engine.py", line 340, in run_iter
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server failure.Failure.reraise_if_any(er_failures)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/taskflow/types/failure.py", line 336, in reraise_if_any
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server failures[0].reraise()
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/taskflow/types/failure.py", line 343, in reraise
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server six.reraise(*self._exc_info)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/taskflow/engines/action_engine/executor.py", line 53, in _execute_task
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server result = task.execute(**arguments)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/flows/manager/create_volume.py", line 1028, in execute
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server model_update = self._create_raw_volume(volume, **volume_spec)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/flows/manager/create_volume.py", line 995, in _create_raw_volume
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server ret = self.driver.create_volume(volume)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/rbd.py", line 859, in create_volume
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server return self._create_encrypted_volume(volume, volume.obj_context)
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/rbd.py", line 829, in _create_encrypted_volume
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server encryption['key_size'])
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/image/image_utils.py", line 744, in decode_cipher
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server cipher_alg, cipher_mode, ivgen_alg = cipher_spec.split('-')
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server AttributeError: 'NoneType' object has no attribute 'split'
2021-04-29 15:16:01.286 58 ERROR oslo_messaging.rpc.server