Internet Engineering Task Force (IETF) Y. Ohba
Request for Comments: 5873 Toshiba
Category: Experimental A. Yegin
ISSN: 2070-1721 Samsung
May 2010
Internet Engineering Task Force (IETF) Y. Ohba
Request for Comments: 5873 Toshiba
Category: Experimental A. Yegin
ISSN: 2070-1721 Samsung
May 2010
Pre-Authentication Support for the Protocol for Carrying Authentication for Network Access (PANA)
对承载网络访问身份验证（PANA）协议的预身份验证支持
Abstract
摘要
This document defines an extension to the Protocol for Carrying Authentication for Network Access (PANA) for proactively establishing a PANA Security Association between a PANA Client in one access network and a PANA Authentication Agent in another access network to which the PANA Client may move.
本文档定义了承载网络访问身份验证（PANA）协议的扩展，用于在一个访问网络中的PANA客户端和PANA客户端可能移动到的另一个访问网络中的PANA身份验证代理之间主动建立PANA安全关联。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation.
本文件不是互联网标准跟踪规范；它是为检查、实验实施和评估而发布的。
This document defines an Experimental Protocol for the Internet community. This document is a product of the Internet Engineering Task Force (IETF). It has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
本文档为互联网社区定义了一个实验协议。本文件是互联网工程任务组（IETF）的产品。互联网工程指导小组（IESG）已批准将其出版。并非IESG批准的所有文件都适用于任何级别的互联网标准；见RFC 5741第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc5873.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc5873.
Copyright Notice
版权公告
Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2010 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Specification of Requirements . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Pre-Authentication Procedure . . . . . . . . . . . . . . . . . 3
4. PANA Extensions . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . . 7
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Specification of Requirements . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Pre-Authentication Procedure . . . . . . . . . . . . . . . . . 3
4. PANA Extensions . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . . 7
The Protocol for Carrying Authentication for Network Access (PANA) [RFC5191] carries Extensible Authentication Protocol (EAP) messages between a PANA Client (PaC) and a PANA Authentication Agent (PAA) in the access network. If the PaC is a mobile device and is capable of moving from one access network to another while running its applications, it is critical for the PaC to perform a handover seamlessly without degrading the performance of the applications during the handover period. When the handover requires the PaC to establish a PANA session with the PAA in the new access network, the signaling to establish the PANA session should be completed as fast as possible. See [RFC5836] for the handover latency requirements.
用于承载网络接入认证（PANA）的协议[RFC5191]在接入网络中的PANA客户端（PaC）和PANA认证代理（PAA）之间承载可扩展认证协议（EAP）消息。如果PaC是移动设备，并且能够在运行其应用程序时从一个接入网络移动到另一个接入网络，则PaC在切换期间无缝执行切换而不降低应用程序的性能至关重要。当切换要求PaC在新接入网中与PAA建立PANA会话时，建立PANA会话的信令应尽快完成。切换延迟要求见[RFC5836]。
This document defines an extension to the PANA protocol [RFC5191] used for proactively executing EAP authentication and establishing a PANA SA (Security Association) between a PaC in an access network and a PAA in another access network to which the PaC may move. The extension to the PANA protocol is designed to realize direct pre-authentication defined in [RFC5836]. How to realize authorization and accounting with the use of the pre-authentication extension is out of the scope of this document.
本文档定义了PANA协议[RFC5191]的扩展，用于主动执行EAP身份验证，并在接入网络中的PaC和PaC可能移动到的另一接入网络中的PAA之间建立PANA SA（安全关联）。PANA协议的扩展旨在实现[RFC5836]中定义的直接预认证。如何使用预认证扩展实现授权和记帐不在本文档的范围之内。
In this document, several words are used to signify the requirements of the specification. These words are often capitalized. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
在本文件中，使用了几个词来表示规范的要求。这些词通常大写。本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[RFC2119]中所述进行解释。
The following terms are used in this document, in addition to the terms defined in [RFC5191].
除[RFC5191]中定义的术语外，本文件中还使用了以下术语。
Serving Network: The access network to which the host is currently attached.
服务网络：主机当前连接到的接入网络。
Candidate Network: An access network that is a potential target of the host's handover.
候选网络：作为主机切换的潜在目标的接入网络。
Serving PAA (SPAA): A PAA that resides in the serving network and provides network access authentication for a particular PaC.
服务PAA（SPAA）：驻留在服务网络中并为特定PaC提供网络访问身份验证的PAA。
Candidate PAA (CPAA): A PAA that resides in a candidate network to which the PaC may move. A CPAA for a particular PaC may be a SPAA for another PaC.
候选PAA（CPAA）：驻留在PaC可以移动到的候选网络中的PAA。特定PaC的CPAA可以是另一个PaC的SPAA。
Pre-authentication: Pre-authentication refers to EAP pre-authentication and is defined as the utilization of EAP to pre-establish EAP keying material on an authenticator prior to arrival of the peer at the access network served by that authenticator [RFC5836]. In this document, EAP pre-authentication is performed between a PaC and a CPAA.
预认证：预认证指EAP预认证，定义为在对等方到达认证方服务的接入网络之前，利用EAP在认证方上预先建立EAP密钥材料[RFC5836]。在本文档中，在PaC和CPAA之间执行EAP预认证。
A PaC that supports pre-authentication may establish a PANA session for each CPAA.
支持预认证的PaC可以为每个CPAA建立PANA会话。
There may be several mechanisms for a PaC to discover a CPAA. An IP address of the discovered CPAA is the output of those mechanisms. PANA pre-authentication is performed between the PaC and CPAA using the discovered IP address of the CPAA. IEEE 802.21 [802.21] Information Service MAY be used as a CPAA discovery mechanism.
PaC发现CPAA可能有几种机制。发现的CPAA的IP地址是这些机制的输出。PANA预认证是使用发现的CPAA的IP地址在PaC和CPAA之间执行的。IEEE 802.21[802.21]信息服务可用作CPAA发现机制。
There may be a number of criteria for CPAA selection, the timing to start pre-authentication, and the timing as to when the CPAA becomes the SPAA. Such criteria can be implementation-specific and thus are outside the scope of this document.
可能存在用于CPAA选择的多个标准、开始预认证的定时以及关于CPAA何时成为SPAA的定时。这些标准可以是具体实施的，因此不在本文件的范围之内。
Pre-authentication is initiated by a PaC in a way similar to normal authentication. A new 'E' (prE-authentication) bit is defined in the PANA header. When pre-authentication is performed, the 'E' (prE-authentication) bit of PANA messages is set in order to indicate that this PANA run is for pre-authentication. Use of pre-authentication is negotiated as follows.
预认证由PaC以类似于普通认证的方式启动。PANA标头中定义了一个新的“E”（预认证）位。当执行预身份验证时，设置PANA消息的“E”（预身份验证）位，以指示此PANA运行用于预身份验证。预认证的使用协商如下。
o When a PaC initiates pre-authentication, it sends a PANA-Client-Initiation (PCI) message with the 'E' (prE-authentication) bit set. The CPAA responds with a PANA-Auth-Request (PAR) message with the 'S' (Start) and 'E' (prE-authentication) bits set only if it supports pre-authentication. Otherwise, the 'E' (prE-authentication) bit of the PAR message will be cleared according to Section 6.2 of [RFC5191], which results in a negotiation failure.
o 当PaC启动预认证时，它将发送一条PANA客户端启动（PCI）消息，其中设置了“E”（预认证）位。仅当CPAA支持预认证时，CPAA才会使用设置了“S”（开始）和“E”（预认证）位的PANA认证请求（PAR）消息进行响应。否则，PAR消息的“E”（预认证）位将根据[RCF5191]的第6.2节被清除，这导致协商失败。
o Once the PaC and CPAA have successfully negotiated on performing pre-authentication using the 'S' (Start) and 'E' (prE-authentication) bits, the subsequent PANA messages exchanged between them MUST have the 'E' (prE-authentication) bit set until the CPAA becomes the SPAA of the PaC. The PaC may conduct this exchange with more than one CPAA. If the PaC and CPAA have failed to negotiate on performing pre-authentication, the PaC or CPAA that sent a message with both the 'S' (Start) and 'E' (prE-authentication) bits set MUST discard the message received from the peer with 'S' (Start) bit set and the 'E' (prE-authentication) bit cleared, which will eventually result in PANA session termination.
o 一旦PaC和CPAA成功协商使用“S”（开始）和“E”（预认证）位执行预认证，它们之间交换的后续PANA消息必须设置“E”（预认证）位，直到CPAA成为PaC的SPAA。PaC可以与多个CPAA进行这种交换。如果PaC和CPAA未能协商执行预认证，则发送同时设置了“S”（开始）和“E”（预认证）位的消息的PaC或CPAA必须丢弃从设置了“S”（开始）位且清除了“E”（预认证）位的对等方接收的消息，这将最终导致PANA会话终止。
If IP reconfiguration is needed in the access network associated with the CPAA, the 'I' (IP Reconfiguration) bit in PAR messages used for pre-authentication between the PaC and CPAA is also set. The 'I' (IP Reconfiguration) bit in these messages takes effect only after the CPAA becomes the SPAA.
如果在与CPAA相关联的接入网络中需要IP重配置，则还设置用于PAC和CPAA之间的预认证的PAR消息中的“I”（IP重配置）位。这些消息中的“I”（IP重新配置）位仅在CPAA成为SPAA后生效。
When a CPAA of the PaC becomes the SPAA, e.g., due to movement of the PaC, the PaC informs the PAA of the change using PANA-Notification-Request (PNR) and PANA-Notification-Answer (PNA) messages with the 'P' (Ping) bit set and the 'E' (prE-authentication) bit cleared. The 'E' (prE-authentication) bit MUST be cleared in subsequent PANA messages.
当PaC的CPAA变为SPAA时，例如，由于PaC的移动，PaC使用PANA通知请求（PNR）和PANA通知应答（PNA）消息通知PAA变更，并设置“P”（Ping）位和清除“e”（预认证）位。必须在后续PANA消息中清除“E”（预认证）位。
A PANA SA is required for pre-authentication in order to securely associate the PNR/PNA exchange to the earlier authentication.
预身份验证需要PANA SA，以便将PNR/PNA交换安全地关联到早期身份验证。
The PANA session between the PaC and a CPAA is deleted by entering the termination phase of the PANA protocol.
PaC和CPAA之间的PANA会话通过进入PANA协议的终止阶段而被删除。
An example call flow for pre-authentication is shown in Figure 1. Note that EAP authentication is performed over PAR and PANA-Auth-Answer (PAN) exchanges, including the one with the 'C' (Complete) bit set.
图1显示了预认证的示例调用流。注意，EAP认证是通过PAR和PANA Auth Answer（PAN）交换进行的，包括具有“C”（完整）位集的EAP认证。
PaC CPAA
| |
+------------------+ |
|Pre-authentication| |
|trigger | |
+------------------+ |
| PCI w/'E' bit set |
|------------------------------------------------>|
| PAR w/'S' and 'E' bits set |
|<------------------------------------------------|
| PAN w/'S' and 'E' bits set |
|------------------------------------------------>|
| PAR-PAN exchange w/'E' bit set |
|<----------------------------------------------->|
| PAR w/'C' and 'E' bits set |
|<------------------------------------------------|
| PAN w/'C' and 'E' bits set |
|------------------------------------------------>|
. . .
. . .
+----------+ |
| Movement | |
+----------+ |
| PNR w/ 'P' bit set and w/o 'E' bit set |
|------------------------------------------------>|
| +-----------------+
| |CPAA becomes SPAA|
| +-----------------+
| PNA w/ 'P' bit set and w/o 'E' bit set |
|<------------------------------------------------|
| |
PaC CPAA
| |
+------------------+ |
|Pre-authentication| |
|trigger | |
+------------------+ |
| PCI w/'E' bit set |
|------------------------------------------------>|
| PAR w/'S' and 'E' bits set |
|<------------------------------------------------|
| PAN w/'S' and 'E' bits set |
|------------------------------------------------>|
| PAR-PAN exchange w/'E' bit set |
|<----------------------------------------------->|
| PAR w/'C' and 'E' bits set |
|<------------------------------------------------|
| PAN w/'C' and 'E' bits set |
|------------------------------------------------>|
. . .
. . .
+----------+ |
| Movement | |
+----------+ |
| PNR w/ 'P' bit set and w/o 'E' bit set |
|------------------------------------------------>|
| +-----------------+
| |CPAA becomes SPAA|
| +-----------------+
| PNA w/ 'P' bit set and w/o 'E' bit set |
|<------------------------------------------------|
| |
Figure 1: Pre-Authentication Call Flow
图1：预认证调用流
A new 'E' (prE-authentication) bit is defined in the Flags field of the PANA header as follows.
在PANA头的标志字段中定义了一个新的“E”（预认证）位，如下所示。
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R S C A P I E r r r r r r r r r|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R S C A P I E r r r r r r r r r|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
'E' (prE-authentication) bit: When pre-authentication is performed, the 'E' (prE-authentication) bit of PANA messages is set in order to indicate whether this PANA run is for pre-authentication. The
“E”（预认证）位：执行预认证时，设置PANA消息的“E”（预认证）位，以指示此PANA运行是否用于预认证。这个
exact usage of this bit is described in Section 3. Bit 6 has been assigned by IANA.
第3节描述了该位的确切用法。第6位已由IANA分配。
Backward compatibility between a PANA entity that does not support the pre-authentication extension and another PANA entity that supports the pre-authentication extension is maintained as follows.
不支持预认证扩展的PANA实体与支持预认证扩展的另一个PANA实体之间的向后兼容性保持如下。
When a PaC that supports the pre-authentication extension initiates PANA pre-authentication by sending a PCI message with the 'E' (prE-authentication) bit set to a PAA that does not support the pre-authentication extension, the PAA will ignore the 'E' (prE-authentication) bit according to Section 6.2 of [RFC5191], and try to process the message as a normal authentication attempt. As a result, the PaC will receive a PAR message with the 'E' (prE-authentication) bit cleared. In this case, the negotiation on the use of pre-authentication will fail, and eventually the PANA session will be terminated as described in Section 3.
当支持预认证扩展的PaC通过向不支持预认证扩展的PAA发送设置了“E”（预认证）位的PCI消息来启动PANA预认证时，PAA将根据[RFC5191]第6.2节忽略“E”（预认证）位，并尝试将该消息作为正常身份验证尝试进行处理。因此，PAC将接收带有“E”（预认证）位清除的PAR消息。在这种情况下，关于使用预认证的协商将失败，最终PANA会话将如第3节所述终止。
This specification is based on the PANA protocol, and it exhibits the same security properties, except for one important difference: Pre-authenticating PaCs are not physically connected to an access network associated with the PAA, but they are connected to some other network somewhere else on the Internet. This distinction can create greater denial-of-service (DoS) vulnerability for systems using PANA pre-authentication if appropriate measures are not taken. An unprotected PAA can be forced to create state by an attacker PaC that merely sends PCI messages.
该规范基于PANA协议，除了一个重要的区别外，它展示了相同的安全属性：预认证PAC没有物理连接到与PAA关联的接入网络，但它们连接到Internet上其他地方的其他网络。如果未采取适当措施，这种区别可能会为使用PANA预认证的系统造成更大的拒绝服务（DoS）漏洞。仅发送PCI消息的攻击者PaC可以强制未受保护的PAA创建状态。
[RFC5191] describes how the PAA can stay stateless while responding to incoming PCIs. PAAs using pre-authentication SHOULD be following those guidelines (see [RFC5191], Section 4.1).
[RFC5191]描述了PAA如何在响应传入PCI时保持无状态。使用预认证的PAAs应遵循这些指南（见[RFC5191]，第4.1节）。
Furthermore, it is recommended that PANA pre-authentication messages be only accepted from PaCs originating from well-known IP networks (e.g., physically adjacent networks) for a given PAA. These IP networks can be used with a whitelist implemented on either the firewall protecting the perimeter around the PAA or the PAA itself. This prevention measure SHOULD be used whenever it can be practically applied to a given deployment.
此外，对于给定的PAA，建议仅从源自已知IP网络（例如，物理相邻网络）的PAC接收PANA预认证消息。这些IP网络可以与在保护PAA周边或PAA本身的防火墙上实现的白名单一起使用。只要可以实际应用于给定的部署，就应该使用这种预防措施。
As described in Section 4, and following the new IANA allocation policy on PANA messages [RFC5872], bit 6 of the Flags field of the PANA header has been assigned by IANA for the 'E' (prE-authentication) bit.
如第4节所述，根据PANA消息的新IANA分配策略[RFC5872]，IANA已为“E”（预认证）位分配了PANA报头标志字段的第6位。
The authors would like to thank Basavaraj Patil, Ashutosh Dutta, Julien Bournelle, Sasikanth Bharadwaj, Subir Das, Rafa Marin Lopez, Lionel Morand, Victor Fajardo, Glen Zorn, Qin Wu, Jari Arkko, Pasi Eronen, and Joseph Salowey for their support and valuable feedback.
作者要感谢巴萨瓦拉吉·帕蒂尔、阿什图什·杜塔、朱利安·博内尔、萨西坎·巴拉德瓦伊、苏比尔·达斯、拉法·马林·洛佩兹、莱昂内尔·莫兰德、维克托·法贾多、格伦·佐恩、秦武、贾里·阿克科、帕西·艾隆和约瑟夫·萨洛维的支持和宝贵反馈。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC5191] Forsberg, D., Ohba, Y., Patil, B., Tschofenig, H., and A. Yegin, "Protocol for Carrying Authentication for Network Access (PANA)", RFC 5191, May 2008.
[RFC5191]Forsberg，D.，Ohba，Y.，Patil，B.，Tschofenig，H.，和A.Yegin，“承载网络接入认证（PANA）的协议”，RFC 51912008年5月。
[RFC5872] Arkko, J. and A. Yegin, "IANA Rules for the Protocol for Carrying Authentication for Network Access (PANA)", RFC 5872, May 2010.
[RFC5872]Arkko，J.和A.Yegin，“承载网络访问认证（PANA）协议的IANA规则”，RFC 5872，2010年5月。
[RFC5836] Ohba, Y., Ed., Wu, Q., Ed., and G. Zorn, Ed., "Extensible Authentication Protocol (EAP) Early Authentication Problem Statement", RFC 5836, April 2010.
[RFC5836]Ohba，Y.，Ed.，Wu，Q.，Ed.，和G.Zorn，Ed.，“可扩展认证协议（EAP）早期认证问题声明”，RFC 58362010年4月。
[802.21] IEEE, "Standard for Local and Metropolitan Area Networks: Media Independent Handover Services", LAN MAN Standards Committee of the IEEE Computer Society 802.21, 2008.
[802.21]IEEE，“局域网和城域网标准：媒体独立切换服务”，IEEE计算机协会局域网标准委员会802.21，2008年。
Authors' Addresses
作者地址
Yoshihiro Ohba Toshiba Corporate Research and Development Center 1 Komukai-Toshiba-cho Saiwai-ku, Kawasaki, Kanagawa 212-8582 Japan
日本神奈川川崎Komukai Toshiba cho Saiwai ku东芝公司研发中心1号，邮编：212-8582
Phone: +81 44 549 2230
EMail: yoshihiro.ohba@toshiba.co.jp
Phone: +81 44 549 2230
EMail: yoshihiro.ohba@toshiba.co.jp
Alper Yegin Samsung Istanbul Turkey
土耳其伊斯坦布尔阿尔珀·耶金酒店
EMail: alper.yegin@yegin.org
EMail: alper.yegin@yegin.org