Internet DRAFT - draft-deng-teep-cvmp
draft-deng-teep-cvmp
Internet Engineering Task Force J. Deng
Internet-Draft
Intended status: Informational G. Yu
Expires: 3 June 2024 1 December 2023
Confidential Virtual Machine Provisioning in Cloud Environment
draft-deng-teep-cvmp-01
Abstract
This document specifies the procedures of provisioning confidential
virtual machine in the cloud environment.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Procedures of CVM Provisioning in Cloud Environment . . . . . 3
3.1. Feature Acquirement . . . . . . . . . . . . . . . . . . . 4
3.2. CVM Creation . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Key Provisioning . . . . . . . . . . . . . . . . . . . . 5
3.3.1. Policy Setup . . . . . . . . . . . . . . . . . . . . 5
3.3.2. Key Allocation . . . . . . . . . . . . . . . . . . . 6
3.3.3. Key Acquirement . . . . . . . . . . . . . . . . . . . 6
3.3.4. Key Update . . . . . . . . . . . . . . . . . . . . . 7
3.4. CVM Management . . . . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5.1. Communication Security Between Key Agent and Key
Server . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Communication Security Between Cloud Tenant and Key
Server . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1. Normative References . . . . . . . . . . . . . . . . . . 8
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 8
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Confidential computing protects workload and data in use leveraging
hardware-based security technology. Confidential virtual machine
(CVM) in the cloud environment is one use case of confidential
computing. There is an increasing adoption of CVMs in the cloud.
CVM allows a cloud tenant to protect the sensitive workload and data,
and manage the cryptography keys independently from the cloud service
providers.
When adopting CVMs in the cloud, the CVM features, CVM provisioning
and management of cryptography keys, etc. depend on different
hardware. Common CVM provisioning procedures and requirements are
needed. This document specifies the procedures of provisioning CVMs
in the cloud environment and the requirements.
2. Terms
The following terms are used in this document.
* CVM Platform: CVM Platform is provided and maintained by cloud
service provider. It provides interfaces for cloud tenant to
create and manage CVM instances on the cloud. It receives the CVM
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related requests from cloud tenant and interacts with cloud
resource manager to perform CVM creation, decommission, update,
migration etc. on the cloud infrastructure.
* Key Agent: Key Agent is the component within a CVM instance that
interacts with Key Server to allocate, acquire and update security
keys, and also provides and update Security Version Number (SVN)
of the CVM.
* Security Version Number (SVN): SVN represents the security
features of the hardware of CVM.
* Key Server: Key Server authenticates Key Agent, responds to Key
Agent's requests to generate, update and return security keys, and
update CVM's SVN.
* Security Key(SK): SK is allocated by Key Server under the request
of Key Agent. SK is used by CVM instance to encrypt sensitive
data.
* KeyID: KeyID identifies a security key.
3. Procedures of CVM Provisioning in Cloud Environment
The procedures of CVM provisioning in Cloud Environment includes the
following:
* Feature Acquirement: Cloud Tenant acquires the CVM related
features that are provided by CVM Platform.
* CVM Creation: Cloud tenant requests CVM instance(s) with selected
features and CVM platform creates the requested CVM instance(s),
and returns the results to the cloud tenant.
* Key Provisioning: the Key Agent in CVM instance obtains and
updates security keys bounded to the CVM through communication
with the Key Server.
* CVM management: Cloud tenant performs various management tasks on
CVM instances, such as CVM updates, live migration, CVM
decommission etc., through interacting with CVM Platform
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3.1. Feature Acquirement
Before creating a CVM instance, Cloud Tenant acquires the supported
CVM features from CVM platform. Figure 1 shows example feature
acquirement between Cloud Tenant and CVM Platform. CVMFeatureRequest
message is sent by Cloud Tenant to CVM Platform requesting the
supported CVM features. CVM returns CVMFeatureResponse carrying a
list of supported features, which may include:
* SecureBoot: whether secure boot is supported.
* LiveMigration: whether live migration is supported.
* AuxilaryFirmware: whether allows Cloud Tenant to specify firmware
to be used.
* BIOS: whether allows Cloud Tenant to customize BIOS.
* SVN: whether allows Cloud Tenant to specifies SVN.
+--------+ +----------+
| Cloud | | CVM |
| Tenant | | Platform |
+--------+ +----------+
| |
| |
| CVMFeatureRequest |
|----------------------------->|
| |
| |
| CVMFeatureResponse |
|<-----------------------------|
| |
Figure 1: CVM feature acquirement
3.2. CVM Creation
Figure 2 shows that Cloud Tenant requests to create CVM instance(s)
and CVM Platform responds with the creation result. In the
CVMCreateRequest message requesting CVM creation, Client tenant
provides the requested features. The features are described as in
Section 3.1. CVM Platform returns with CVMCreateResponse. If the
creation is successful, in CVMCreateResponse message, CVM Platform
indicated successful CVM creation and returns information on the
features requested by Cloud Tenant.
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+--------+ +----------+
| Cloud | | CVM |
| Tenant | | Platform |
+--------+ +----------+
| |
| CVMCreateRequest |
|-------------------------->|
| |
| CVMCreateResponse |
|<--------------------------|
| |
Figure 2: CVM instance creation
3.3. Key Provisioning
The key provisioning consists of Policy Setup, Key Allocation, Key
Acquirement, and Key Update between Key Agent and Key Server.
* Policy Setup: Cloud Tenant provide Key Server with Keying Policy.
* Key Allocation: Key Agent requests Key Server to allocate a new
security key.
* Key Acquirement: Key Agent obtains a pre-allocated security key by
providing the KeyID to Key Server.
* Key Update: Key Agent updates its SVN with Key Server.
The security considerations for the communication between Key Agent
and Key Server are presented in Section 5.
3.3.1. Policy Setup
In Policy Setup, Cloud Tenant provides Key server with information
needed for Key Allocation, Key Acquirement, and Key Update. The
information at least includes SVN, measurements, etc. Figure 3 shows
example Keying Policy setup between Key Agent and Key Server.
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+--------+ +--------+
| Cloud | | Key |
| Tenant | | Server |
+--------+ +--------+
| |
| SetKeyPolicy |
|-------------------------------->|
| |
| PolicyResponse |
|<--------------------------------|
| |
Figure 3: Key provisioning
3.3.2. Key Allocation
Figure 4 shows example key allocation. Key Agent sends
KeyAllocRequest message to Key Server to request a new security key.
Key Server then allocates a KeyID, generates and saves a root key for
Key Agent, derives a security key from the root key with input
parameters including the SVN provided by Key Agent, and returns the
KeyID and Security Key. Allocation usually occurs when CVM is started
for the first time, and CVM needs to use Security Key for encryption.
+--------+ +--------+
| Key | | Key |
| Agent | | Server |
+--------+ +--------+
| |
| KeyAllocRequest |
|-------------------------------->|
| KeyAllocResponse |
|<--------------------------------|
Figure 4: Key provisioning
3.3.3. Key Acquirement
Figure 5 shows example key acquirement where Key Agent acquires a
pre-allocated Security Key with the KeyID.
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+--------+ +--------+
| Key | | Key |
| Agent | | Server |
+--------+ +--------+
| |
| KeyAcquireRequest |
|-------------------------------->|
| KeyAcquireResponse |
|<--------------------------------|
Figure 5: Key provisioning
3.3.4. Key Update
Key Agent within a CVM may chose to update the minimal required SVN
of the Key by sending KeyUpdateRequest to Key Server. Key Server
will only update the SVN if the old SVN with the Key Agent is lower
than the target SVN. After successful SVN update, a Key Agent with
outdated SVN cannot acquire the Security Key with the pre-allocated
KeyID. A CVM which meets the requirement of minimum SVN can request
the Key Server to re-allocate a new Security Key from the
corresponding root key. Figure 6 shows example key update.
+--------+ +--------+
| Key | | Key |
| Agent | | Server |
+--------+ +--------+
| |
| KeyUpdateRequest |
|-------------------------------->|
| KeyUpdateResponse |
|<--------------------------------|
Figure 6: Key Update
3.4. CVM Management
This section presents the procedures for CVM management.
4. IANA Considerations
This memo includes no request to IANA.
5. Security Considerations
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5.1. Communication Security Between Key Agent and Key Server
Key Agent and Key server are mutually authenticated and the
communications between them are confidentially and integrity
protected. The security can leverage the attestation evidence in
[RFC9334]. The messages can use CBOR and the security wrapper as in
[RFC9052].
5.2. Communication Security Between Cloud Tenant and Key Server
This section considers the communication security between Cloud
Tenant and Key Server.
6. References
6.1. Normative References
[RFC9334] Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote ATtestation procedureS (RATS)
Architecture", RFC 9334, DOI 10.17487/RFC9334, January
2023, <https://www.rfc-editor.org/info/rfc9334>.
[RFC9052] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Structures and Process", STD 96, RFC 9052,
DOI 10.17487/RFC9052, August 2022,
<https://www.rfc-editor.org/info/rfc9052>.
Acknowledgements
Contributors
Authors' Addresses
Juan Deng
Email: dengjuan.deng@alibaba-inc.com
Guorui Yu
Email: ruogui.ygr@alibaba-inc.com
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