RFC4462 日本語訳
4462 Generic Security Service Application Program Interface (GSS-API)Authentication and Key Exchange for the Secure Shell (SSH) Protocol.J. Hutzelman, J. Salowey, J. Galbraith, V. Welch. May 2006. (Format: TXT=65280 bytes) (Status: PROPOSED STANDARD)
プログラムでの自動翻訳です。
英語原文
Network Working Group J. Hutzelman
Request for Comments: 4462 CMU
Category: Standards Track J. Salowey
Cisco Systems
J. Galbraith
Van Dyke Technologies, Inc.
V. Welch
U Chicago / ANL
May 2006
Hutzelmanがコメントのために要求するワーキンググループJ.をネットワークでつないでください: 4462年の米カーネギーメロン大学カテゴリ: 標準化過程J.SaloweyシスコシステムズJ.ガルブレイスヴァンダイク技術Inc.V.ウェルチUシカゴ/ANL2006年5月
Generic Security Service Application Program Interface (GSS-API)
Authentication and Key Exchange for the Secure Shell (SSH) Protocol
セキュア・シェル(セキュアシェル (SSH))プロトコルへのジェネリックセキュリティー・サービス適用業務プログラム・インタフェース(GSS-API)認証と主要な交換
Status of This Memo
このメモの状態
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
このドキュメントは、インターネットコミュニティにインターネット標準化過程プロトコルを指定して、改良のために議論と提案を要求します。 このプロトコルの標準化状態と状態への「インターネット公式プロトコル標準」(STD1)の現行版を参照してください。 このメモの分配は無制限です。
Copyright Notice
版権情報
Copyright (C) The Internet Society (2006).
Copyright(C)インターネット協会(2006)。
Abstract
要約
The Secure Shell protocol (SSH) is a protocol for secure remote login and other secure network services over an insecure network.
Secureシェルプロトコル(SSH)は不安定なネットワークの上の安全なリモート・ログインと他の安全なネットワーク・サービスのためのプロトコルです。
The Generic Security Service Application Program Interface (GSS-API) provides security services to callers in a mechanism-independent fashion.
Generic Security Service Application Program Interface(GSS-API)はメカニズムから独立しているファッションに訪問者へのセキュリティー・サービスを提供します。
This memo describes methods for using the GSS-API for authentication and key exchange in SSH. It defines an SSH user authentication method that uses a specified GSS-API mechanism to authenticate a user, and a family of SSH key exchange methods that use GSS-API to authenticate a Diffie-Hellman key exchange.
このメモはSSHの認証と主要な交換にGSS-APIを使用するためのメソッドを説明します。 それはユーザを認証するのに指定されたGSS-APIメカニズムを使用するSSHユーザー認証メソッド、およびディフィー-ヘルマンの主要な交換を認証するのにGSS-APIを使用するSSHの主要な交換メソッドのファミリーを定義します。
This memo also defines a new host public key algorithm that can be used when no operations are needed using a host's public key, and a new user authentication method that allows an authorization name to be used in conjunction with any authentication that has already occurred as a side-effect of GSS-API-based key exchange.
また、このメモは操作が全くホストの公開鍵を使用することで必要でないときに使用できる、新しいホスト公開鍵アルゴリズム、および承認名がGSS APIベースの主要な交換の副作用として既に起こったどんな認証に関連して使用されるのを許容する新しいユーザー認証メソッドを定義します。
Hutzelman, et al. Standards Track [Page 1] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[1ページ]。
Table of Contents
目次
1. Introduction ....................................................3
1.1. SSH Terminology ............................................3
1.2. Key Words ..................................................3
2. GSS-API-Authenticated Diffie-Hellman Key Exchange ...............3
2.1. Generic GSS-API Key Exchange ...............................4
2.2. Group Exchange ............................................10
2.3. gss-group1-sha1-* .........................................11
2.4. gss-group14-sha1-* ........................................12
2.5. gss-gex-sha1-* ............................................12
2.6. Other GSS-API Key Exchange Methods ........................12
3. GSS-API User Authentication ....................................13
3.1. GSS-API Authentication Overview ...........................13
3.2. Initiating GSS-API Authentication .........................13
3.3. Initial Server Response ...................................14
3.4. GSS-API Session ...........................................15
3.5. Binding Encryption Keys ...................................16
3.6. Client Acknowledgement ....................................16
3.7. Completion ................................................17
3.8. Error Status ..............................................17
3.9. Error Token ...............................................18
4. Authentication Using GSS-API Key Exchange ......................19
5. Null Host Key Algorithm ........................................20
6. Summary of Message Numbers .....................................21
7. GSS-API Considerations .........................................22
7.1. Naming Conventions ........................................22
7.2. Channel Bindings ..........................................22
7.3. SPNEGO ....................................................23
8. IANA Considerations ............................................24
9. Security Considerations ........................................24
10. Acknowledgements ..............................................25
11. References ....................................................26
11.1. Normative References .....................................26
11.2. Informative References ...................................27
1. 序論…3 1.1. セキュアシェル (SSH)用語…3 1.2. キーワード…3 2. APIが認証したGSSのディフィー-ヘルマンの主要なExchange…3 2.1. ジェネリックのGSS-APIの主要な交換…4 2.2. 交換を分類してください…10 2.3 gss-group1-sha1-*…11 2.4 gss-group14-sha1-*…12 2.5 gss-gex-sha1-*…12 2.6. 他のGSS-APIの主要な交換メソッド…12 3. GSS-APIユーザー認証…13 3.1. GSS-API認証概要…13 3.2. GSS-API認証を開始します…13 3.3. サーバ応答に頭文字をつけてください…14 3.4. GSS-APIセッション…15 3.5. 暗号化キーを縛ります…16 3.6. クライアント承認…16 3.7. 完成…17 3.8. 誤り状態…17 3.9. 誤りトークン…18 4. GSS-APIの主要な交換を使用する認証…19 5. ヌルホスト主要なアルゴリズム…20 6. メッセージ番号の概要…21 7. GSS-API問題…22 7.1. コンベンションを命名します…22 7.2. チャンネル結合…22 7.3. SPNEGO…23 8. IANA問題…24 9. セキュリティ問題…24 10. 承認…25 11. 参照…26 11.1. 標準の参照…26 11.2. 有益な参照…27
Hutzelman, et al. Standards Track [Page 2] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[2ページ]。
1. Introduction
1. 序論
This document describes the methods used to perform key exchange and user authentication in the Secure Shell protocol using the GSS-API. To do this, it defines a family of key exchange methods, two user authentication methods, and a new host key algorithm. These definitions allow any GSS-API mechanism to be used with the Secure Shell protocol.
このドキュメントはSecureシェルプロトコルで主要な交換とユーザー認証を実行するのにGSS-APIを使用することで使用されるメソッドを説明します。 これをするために、それは主要な交換メソッド、2つのユーザー認証メソッド、および新しいホストキーアルゴリズムのファミリーを定義します。 これらの定義は、どんなGSS-APIメカニズムもSecureシェルプロトコルと共に使用されるのを許容します。
This document should be read only after reading the documents describing the SSH protocol architecture [SSH-ARCH], transport layer protocol [SSH-TRANSPORT], and user authentication protocol [SSH-USERAUTH]. This document freely uses terminology and notation from the architecture document without reference or further explanation.
このドキュメントは読んだ後の書き込み禁止であるべきです。 このドキュメントはアーキテクチャドキュメントから参照も詳細な説明なしで用語と記法を自由に使用します。
1.1. SSH Terminology
1.1. セキュアシェル (SSH)用語
The data types used in the packets are defined in the SSH architecture document [SSH-ARCH]. It is particularly important to note the definition of string allows binary content.
パケットで使用されるデータ型はSSHアーキテクチャドキュメント[SSH-ARCH]で定義されます。 ストリングの定義が2進の内容を許容することに注意するのは特に重要です。
The SSH_MSG_USERAUTH_REQUEST packet refers to a service; this service name is an SSH service name and has no relationship to GSS-API service names. Currently, the only defined service name is "ssh-connection", which refers to the SSH connection protocol [SSH-CONNECT].
SSH_エムエスジー_USERAUTH_REQUESTパケットはサービスについて言及します。 このサービス名は、SSHサービス名であり、GSS-APIサービス名との関係を全く持っていません。 現在、唯一の定義されたサービス名がSSH接続プロトコル[SSH-CONNECT]を示す「セキュアシェル (SSH)接続」です。
1.2. Key Words
1.2. キーワード
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 [KEYWORDS].
キーワード“MUST"、「必須NOT」が「必要です」、“SHALL"、「」、“SHOULD"、「「推薦され」て、「5月」の、そして、「任意」のNOTは[キーワード]で説明されるように本書では解釈されることであるべきですか?
2. GSS-API-Authenticated Diffie-Hellman Key Exchange
2. APIが認証したGSSのディフィー-ヘルマンの主要なExchange
This section defines a class of key exchange methods that combine the Diffie-Hellman key exchange from Section 8 of [SSH-TRANSPORT] with mutual authentication using GSS-API.
このセクションは、互いの認証で[SSH-TRANSPORT]のセクション8からGSS-APIを使用することでディフィー-ヘルマンの主要な交換を結合する主要な交換メソッドのクラスを定義します。
Since the GSS-API key exchange methods described in this section do not require the use of public key signature or encryption algorithms, they MAY be used with any host key algorithm, including the "null" algorithm described in Section 5.
このセクションで説明されたGSS-APIの主要な交換メソッドが公開鍵署名か暗号化アルゴリズムの使用を必要としないので、それらはどんなホストキーアルゴリズムでも使用されるかもしれません、セクション5で説明された「ヌル」のアルゴリズムを含んでいて。
Hutzelman, et al. Standards Track [Page 3] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[3ページ]。
2.1. Generic GSS-API Key Exchange
2.1. ジェネリックのGSS-APIの主要な交換
The following symbols are used in this description:
以下のシンボルはこの記述に使用されます:
o C is the client, and S is the server
o Cはクライアントです、そして、Sはサーバです。
o p is a large safe prime, g is a generator for a subgroup of GF(p),
and q is the order of the subgroup
o pは大きい安全な主要です、そして、gはGF(p)のサブグループのためのジェネレータです、そして、qはサブグループの注文です。
o V_S is S's version string, and V_C is C's version string
o V_SはSのバージョンストリングです、そして、V_CはCのバージョンストリングです。
o I_C is C's KEXINIT message, and I_S is S's KEXINIT message
o I_CはCのKEXINITメッセージです、そして、I_SはSのKEXINITメッセージです。
1. C generates a random number x (1 < x < q) and computes e = g^x
mod p.
1. Cは、乱数がx(1<xの<q)であると生成して、g^x e=モッズpを計算します。
2. C calls GSS_Init_sec_context(), using the most recent reply token
received from S during this exchange, if any. For this call, the
client MUST set mutual_req_flag to "true" to request that mutual
authentication be performed. It also MUST set integ_req_flag to
"true" to request that per-message integrity protection be
supported for this context. In addition, deleg_req_flag MAY be
set to "true" to request access delegation, if requested by the
user. Since the key exchange process authenticates only the
host, the setting of anon_req_flag is immaterial to this process.
If the client does not support the "gssapi-keyex" user
authentication method described in Section 4, or does not intend
to use that method in conjunction with the GSS-API context
established during key exchange, then anon_req_flag SHOULD be set
to "true". Otherwise, this flag MAY be set to true if the client
wishes to hide its identity. Since the key exchange process will
involve the exchange of only a single token once the context has
been established, it is not necessary that the GSS-API context
support detection of replayed or out-of-sequence tokens. Thus,
replay_det_req_flag and sequence_req_flag need not be set for
this process. These flags SHOULD be set to "false".
2. この交換の間にSからもしあれば受け取られた最新の回答トークンを使用して、Cは、GSS_Init_を秒_文脈()と呼びます。 この呼び出しのために、クライアントは互いの認証が実行されるよう要求するために「本当に」互いの_req_旗を設定しなければなりません。 また、それは1メッセージの保全あたりの保護がこの文脈のためにサポートされるよう要求するために「本当に」integ_req_旗を設定しなければなりません。 さらに、ユーザによって要求されるなら、「本当に」deleg_req_旗がアクセス委譲を要求するように設定されるかもしれません。 プロセスがやがてホストだけ、設定を認証する主要な交換以来、_req_旗はこのプロセスに重要でないです。 クライアントであるなら、サポートユーザー認証メソッドがセクション4で説明するか、またはGSS-API文脈に関連したメソッドがやがて次に、主要な交換、_の間に確立した使用に意図しない"gssapi-keyex"req_旗のSHOULDは「本当に」用意ができていませんか? さもなければ、クライアントがアイデンティティを隠したいなら、この旗は本当に設定されるかもしれません。 文脈がいったん確立されると主要な交換プロセスがただ一つのトークンだけの交換にかかわるので、GSS-API文脈が再演されることの検出か順序が狂ってトークンをサポートするのは必要ではありません。 したがって、_req_旗と系列_req_が旗を揚げさせる再生_detはこのプロセスに用意ができる必要はありません。 これらはSHOULDに旗を揚げさせます。「誤っていること」に設定されます。
* If the resulting major_status code is GSS_S_COMPLETE and the
mutual_state flag is not true, then mutual authentication has
not been established, and the key exchange MUST fail.
* 結果として起こる主要な_ステータスコードがGSS_であるなら、S_COMPLETEと互いの_州旗は本当ではありません、そして、次に、互いの認証は確立されていません、そして、主要な交換は失敗しなければなりません。
* If the resulting major_status code is GSS_S_COMPLETE and the
integ_avail flag is not true, then per-message integrity
protection is not available, and the key exchange MUST fail.
* 結果として起こる主要な_ステータスコードがGSSであるなら、S_COMPLETEとinteg_利益が旗を揚げさせる_は本当ではありません、そして、そして、メッセージの保全あたりの保護は利用可能ではありません、そして、主要な交換は失敗しなければなりません。
* If the resulting major_status code is GSS_S_COMPLETE and both
the mutual_state and integ_avail flags are true, the resulting
output token is sent to S.
* 結果として起こる主要な_ステータスコードがGSS_S_であるなら、本当に、結果として起こる出力トークンをSに送ります。
Hutzelman, et al. Standards Track [Page 4] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[4ページ]。
* If the resulting major_status code is GSS_S_CONTINUE_NEEDED,
the output_token is sent to S, which will reply with a new
token to be provided to GSS_Init_sec_context().
* 結果として起こる主要な_ステータスコードがCONTINUE_が必要としたGSS_S_であるなら、出力_トークンをSに送ります。(それは、GSS_Init_秒_文脈()に提供するために新しいトークンで返答するでしょう)。
* The client MUST also include "e" with the first message it
sends to the server during this process; if the server
receives more than one "e" or none at all, the key exchange
fails.
* また、クライアントはそれがこのプロセスの間にサーバに送る最初のメッセージで「e」を入れなければなりません。 サーバが1つ「e」か全くなにもより受信されるなら、主要な交換は失敗します。
* It is an error if the call does not produce a token of non-
zero length to be sent to the server. In this case, the key
exchange MUST fail.
* 呼び出しがサーバに送られる非ゼロ・レングスのトークンを生産しないなら、それは誤りです。この場合、主要な交換は失敗しなければなりません。
3. S calls GSS_Accept_sec_context(), using the token received from
C.
3. Cから受け取られたトークンを使用して、Sは、GSS_Accept_を秒_文脈()と呼びます。
* If the resulting major_status code is GSS_S_COMPLETE and the
mutual_state flag is not true, then mutual authentication has
not been established, and the key exchange MUST fail.
* 結果として起こる主要な_ステータスコードがGSS_であるなら、S_COMPLETEと互いの_州旗は本当ではありません、そして、次に、互いの認証は確立されていません、そして、主要な交換は失敗しなければなりません。
* If the resulting major_status code is GSS_S_COMPLETE and the
integ_avail flag is not true, then per-message integrity
protection is not available, and the key exchange MUST fail.
* 結果として起こる主要な_ステータスコードがGSSであるなら、S_COMPLETEとinteg_利益が旗を揚げさせる_は本当ではありません、そして、そして、メッセージの保全あたりの保護は利用可能ではありません、そして、主要な交換は失敗しなければなりません。
* If the resulting major_status code is GSS_S_COMPLETE and both
the mutual_state and integ_avail flags are true, then the
security context has been established, and processing
continues with step 4.
* 結果として起こる主要な_ステータスコードがS_COMPLETEと両方の互いの_が述べるGSS_であり、integ_利益旗が本当であるなら、セキュリティ文脈は確立されました、そして、処理はステップ4を続行します。
* If the resulting major_status code is GSS_S_CONTINUE_NEEDED,
then the output token is sent to C, and processing continues
with step 2.
* 結果として起こる主要な_ステータスコードがCONTINUE_が必要としたGSS_S_であるなら、出力トークンをCに送ります、そして、処理はステップ2を続行します。
* If the resulting major_status code is GSS_S_COMPLETE, but a
non-zero-length reply token is returned, then that token is
sent to the client.
* 結果として起こる主要な_ステータスコードが_GSS_S COMPLETE、非ゼロ・レングス回答トークンだけを返すということであるなら、そのトークンをクライアントに送ります。
4. S generates a random number y (0 < y < q) and computes f = g^y
mod p. It computes K = e ^ y mod p, and H = hash(V_C || V_S ||
I_C || I_S || K_S || e || f || K). It then calls GSS_GetMIC() to
obtain a GSS-API message integrity code for H. S then sends f
and the message integrity code (MIC) to C.
4. Sは、乱数がy(0<y<q)であると生成して、g^y f=モッズpを計算します。 それはK=e^yモッズp、およびH=ハッシュ(V_C| | V_S| | I_C| | I_S| | K_S| | e| | f| | K)を計算します。 そして、それは、次にH.Sのためのコードがfを送るGSS-APIメッセージの保全とメッセージの保全コード(MIC)をCまで得るためにGSS_GetMIC()と呼びます。
5. This step is performed only (1) if the server's final call to
GSS_Accept_sec_context() produced a non-zero-length final reply
token to be sent to the client and (2) if no previous call by the
client to GSS_Init_sec_context() has resulted in a major_status
of GSS_S_COMPLETE. Under these conditions, the client makes an
5. (1) GSS_Accept_秒_文脈()へのサーバの最終案内が単にクライアントに送られる非ゼロ・レングスの最終的な回答トークンを生産して、(2) GSS_Init_秒_文脈()へのクライアントによるどんな前の電話するのが_GSS_S COMPLETEの主要な_状態をもたらしていないなら、このステップは実行されます。 これらの条件で、クライアントは作ります。
Hutzelman, et al. Standards Track [Page 5] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[5ページ]。
additional call to GSS_Init_sec_context() to process the final
reply token. This call is made exactly as described above.
However, if the resulting major_status is anything other than
GSS_S_COMPLETE, or a non-zero-length token is returned, it is an
error and the key exchange MUST fail.
最終的な回答トークンを処理するGSS_Init_秒_文脈()への追加呼び出し。 ちょうど上で説明されるようにこの電話をかけます。 しかしながら、結果として起こる主要な_状態が_GSS_S COMPLETE以外の何かであるか非ゼロ・レングストークンを返すなら、それは誤りです、そして、主要な交換は失敗しなければなりません。
6. C computes K = f^x mod p, and H = hash(V_C || V_S || I_C || I_S
|| K_S || e || f || K). It then calls GSS_VerifyMIC() to verify
that the MIC sent by S matches H. If the MIC is not successfully
verified, the key exchange MUST fail.
6. CはK=f^xモッズp、およびH=ハッシュ(V_C| | V_S| | I_C| | I_S| | K_S| | e| | f| | K)を計算します。 次に、それは、MICがSマッチH.で発信したことを確かめるためにGSS_VerifyMIC()と呼びます。If MICは首尾よく確かめられないで、主要な交換は失敗しなければなりません。
Either side MUST NOT send or accept e or f values that are not in the range [1, p-1]. If this condition is violated, the key exchange fails.
どちらの側も、範囲[1、p-1]にないeかf値を、送ってはいけませんし、また受け入れてはいけません。 この状態が違反されるなら、主要な交換は失敗します。
If any call to GSS_Init_sec_context() or GSS_Accept_sec_context() returns a major_status other than GSS_S_COMPLETE or GSS_S_CONTINUE_NEEDED, or any other GSS-API call returns a major_status other than GSS_S_COMPLETE, the key exchange fails. In this case, several mechanisms are available for communicating error information to the peer before terminating the connection as required by [SSH-TRANSPORT]:
If any call to GSS_Init_sec_context() or GSS_Accept_sec_context() returns a major_status other than GSS_S_COMPLETE or GSS_S_CONTINUE_NEEDED, or any other GSS-API call returns a major_status other than GSS_S_COMPLETE, the key exchange fails. この場合、数個のメカニズムが必要に応じて[SSH-TRANSPORT]で接続を終える前にエラー情報を同輩に伝えるのに利用可能です:
o If the key exchange fails due to any GSS-API error on the server
(including errors returned by GSS_Accept_sec_context()), the
server MAY send a message informing the client of the details of
the error. In this case, if an error token is also sent (see
below), then this message MUST be sent before the error token.
o 交換はキーであるならサーバにおけるどんなGSS-API誤りのためも失敗します。(誤りを含んでいるのはGSS_Accept_秒_文脈())で戻って、メッセージはサーバで誤りの詳細についてクライアントに知らせるかもしれません。 この場合、また、誤りトークンを送るなら(以下を見てください)、誤りトークンの前にこのメッセージを送らなければなりません。
o If the key exchange fails due to a GSS-API error returned from the
server's call to GSS_Accept_sec_context(), and an "error token" is
also returned, then the server SHOULD send the error token to the
client to allow completion of the GSS security exchange.
o 主要な交換がサーバの呼び出しからGSS_Accept_秒_文脈()まで返されたGSS-API誤りのため失敗して、また、「誤りトークン」を返すなら、サーバSHOULDは、GSSセキュリティ交換の完成を許すために誤りトークンをクライアントに送ります。
o If the key exchange fails due to a GSS-API error returned from the
client's call to GSS_Init_sec_context(), and an "error token" is
also returned, then the client SHOULD send the error token to the
server to allow completion of the GSS security exchange.
o 主要な交換がクライアントの呼び出しからGSS_Init_秒_文脈()まで返されたGSS-API誤りのため失敗して、また、「誤りトークン」を返すなら、クライアントSHOULDは、GSSセキュリティ交換の完成を許すために誤りトークンをサーバに送ります。
As noted in Section 9, it may be desirable under site security policy to obscure information about the precise nature of the error; thus, it is RECOMMENDED that implementations provide a method to suppress these messages as a matter of policy.
セクション9に述べられるように、誤りの正確な本質の情報をあいまいにするのはサイト安全保障政策の下で望ましいかもしれません。 したがって、実装が政策の問題としてこれらのメッセージを削除するメソッドを提供するのは、RECOMMENDEDです。
This is implemented with the following messages. The hash algorithm for computing the exchange hash is defined by the method name, and is called HASH. The group used for Diffie-Hellman key exchange and the underlying GSS-API mechanism are also defined by the method name.
これは以下のメッセージで実装されます。 交換ハッシュを計算するためのハッシュアルゴリズムは、メソッド名によって定義されて、HASHと呼ばれます。 また、ディフィー-ヘルマンの主要な交換と基本的なGSS-APIメカニズムに使用されるグループはメソッド名によって定義されます。
Hutzelman, et al. Standards Track [Page 6] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[6ページ]。
After the client's first call to GSS_Init_sec_context(), it sends the following:
クライアントのものが最初にGSS_Init_秒_文脈()に呼びかけた後に、以下を送ります:
byte SSH_MSG_KEXGSS_INIT
string output_token (from GSS_Init_sec_context())
mpint e
KEXGSS_INITが結ぶバイトSSH_エムエスジー_が_トークンを出力した、(GSS_Init_秒_文脈())mpint e
Upon receiving the SSH_MSG_KEXGSS_INIT message, the server MAY send the following message, prior to any other messages, to inform the client of its host key.
SSH_エムエスジー_KEXGSS_INITメッセージを受け取ると、サーバは、いかなる他のメッセージの前にもホストキーについてクライアントに知らせるために以下のメッセージを送るかもしれません。
byte SSH_MSG_KEXGSS_HOSTKEY
string server public host key and certificates (K_S)
バイトSSH_エムエスジー_KEXGSS_HOSTKEYストリングサーバ公衆ホストキーと証明書(K_S)
Since this key exchange method does not require the host key to be used for any encryption operations, this message is OPTIONAL. If the "null" host key algorithm described in Section 5 is used, this message MUST NOT be sent. If this message is sent, the server public host key(s) and/or certificate(s) in this message are encoded as a single string, in the format specified by the public key type in use (see [SSH-TRANSPORT], Section 6.6).
この主要な交換メソッドが、ホストキーがどんな暗号化操作にも使用されるのを必要としないので、このメッセージはOPTIONALです。 セクション5で説明された「ヌル」のホストキーアルゴリズムが使用されているなら、このメッセージを送ってはいけません。 このメッセージを送るなら、一連としてこのメッセージのサーバの公共のホストキー、そして/または、証明書をコード化します、公開鍵タイプによって使用中に指定された形式で([SSH-TRANSPORT]を見てください、セクション6.6)。
In traditional SSH deployments, host keys are normally expected to change infrequently, and there is often no mechanism for validating host keys not already known to the client. As a result, the use of a new host key by an already-known host is usually considered an indication of a possible man-in-the-middle attack, and clients often present strong warnings and/or abort the connection in such cases.
伝統的なSSH展開には、通常、ホストキーがまれに変化すると予想されて、クライアントにとって既に知られなかったホストキーを有効にするためのメカニズムが全くしばしばあるというわけではありません。 その結果、通常、既知のホストで主要な新しいホストの使用が可能な介入者攻撃のしるしであると考えられて、クライアントは、しばしば強い警告を提示する、そして/または、そのような場合接続を中止します。
By contrast, when GSS-API-based key exchange is used, host keys sent via the SSH_MSG_KEXGSS_HOSTKEY message are authenticated as part of the GSS-API key exchange, even when previously unknown to the client. Further, in environments in which GSS-API-based key exchange is used heavily, it is possible and even likely that host keys will change much more frequently and/or without advance warning.
GSS APIベースの主要な交換が使用されているとき、対照的に、SSH_エムエスジー_KEXGSS_HOSTKEYメッセージで送られたホストキーはGSS-APIの主要な交換の一部として認証されます、以前にクライアントにとって未知であることのときにさえ。 さらに、GSS APIベースの主要な交換が大いに使用される環境で、可能であって、ホストキーははるかに頻繁事前の警告なしで変化さえしそうでしょう。
Therefore, when a new key for an already-known host is received via the SSH_MSG_KEXGSS_HOSTKEY message, clients SHOULD NOT issue strong warnings or abort the connection, provided the GSS-API-based key exchange succeeds.
したがって、SSH_エムエスジー_KEXGSS_HOSTKEYメッセージで既知のホストのための新しいキーを受け取るとき、クライアントSHOULD NOTは強い警告を発行するか、または接続を中止します、GSS APIベースの主要な交換が成功するなら。
In order to facilitate key re-exchange after the user's GSS-API credentials have expired, client implementations SHOULD store host keys received via SSH_MSG_KEXGSS_HOSTKEY for the duration of the session, even when such keys are not stored for long-term use.
ユーザのGSS-API資格証明書が期限が切れた後に主要な再交換を容易にするために、クライアント実装SHOULDは_セッションの持続時間のためのSSH_エムエスジーKEXGSS_HOSTKEYを通して受け取られたホストキーを保存します、そのようなキーが長期の使用のために保存さえされないとき。
Hutzelman, et al. Standards Track [Page 7] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[7ページ]。
Each time the server's call to GSS_Accept_sec_context() returns a major_status code of GSS_S_CONTINUE_NEEDED, it sends the following reply to the client:
GSS_Accept_秒_文脈()へのサーバの呼び出しがCONTINUE_が必要としたGSS_S_の主要な_ステータスコードを返す各回、以下の回答をクライアントに送ります:
byte SSH_MSG_KEXGSS_CONTINUE
string output_token (from GSS_Accept_sec_context())
KEXGSS_CONTINUEが結ぶバイトSSH_エムエスジー_は_トークンを出力しました。(GSS_から、_秒_文脈())を受け入れてください。
If the client receives this message after a call to GSS_Init_sec_context() has returned a major_status code of GSS_S_COMPLETE, a protocol error has occurred and the key exchange MUST fail.
GSS_Init_秒_文脈()への呼び出しが_GSS_S COMPLETEの主要な_ステータスコードを返した後にクライアントがこのメッセージを受け取るなら、プロトコル誤りは発生しました、そして、主要な交換は失敗しなければなりません。
Each time the client receives the message described above, it makes another call to GSS_Init_sec_context(). It then sends the following:
クライアントが上で説明されたメッセージを受け取るたびに別のものはそれでGSS_Init_秒_文脈()に呼びかけます。 次に、それは以下を送ります:
byte SSH_MSG_KEXGSS_CONTINUE
string output_token (from GSS_Init_sec_context())
KEXGSS_CONTINUEが結ぶバイトSSH_エムエスジー_は_トークンを出力しました。(GSS_イニット_秒_文脈())
The server and client continue to trade these two messages as long as the server's calls to GSS_Accept_sec_context() result in major_status codes of GSS_S_CONTINUE_NEEDED. When a call results in a major_status code of GSS_S_COMPLETE, it sends one of two final messages.
サーバとクライアントは、GSS_Accept_秒_文脈()へのサーバの呼び出しがCONTINUE_が必要としたGSS_S_の主要な_ステータスコードをもたらす限り、これらの2つのメッセージを取り引きし続けています。 呼び出しが_GSS_S COMPLETEの主要な_ステータスコードをもたらすとき、それは2つの最終的なメッセージの1つを送ります。
If the server's final call to GSS_Accept_sec_context() (resulting in a major_status code of GSS_S_COMPLETE) returns a non-zero-length token to be sent to the client, it sends the following:
GSS_Accept_秒_文脈()(_GSS_S COMPLETEの主要な_ステータスコードをもたらします)へのサーバの最終案内がクライアントに送られる非ゼロ・レングストークンを返すなら、以下を送ります:
byte SSH_MSG_KEXGSS_COMPLETE
mpint f
string per_msg_token (MIC of H)
boolean TRUE
string output_token (from GSS_Accept_sec_context())
SSH_エムエスジー_KEXGSS_COMPLETE mpint fが_msg_トークン(HのMIC)論理演算子TRUEストリング出力_トークン単位で結ぶバイト(GSS_から、_秒_文脈())を受け入れてください。
If the client receives this message after a call to GSS_Init_sec_context() has returned a major_status code of GSS_S_COMPLETE, a protocol error has occurred and the key exchange MUST fail.
GSS_Init_秒_文脈()への呼び出しが_GSS_S COMPLETEの主要な_ステータスコードを返した後にクライアントがこのメッセージを受け取るなら、プロトコル誤りは発生しました、そして、主要な交換は失敗しなければなりません。
If the server's final call to GSS_Accept_sec_context() (resulting in a major_status code of GSS_S_COMPLETE) returns a zero-length token or no token at all, it sends the following:
ゼロ・レングストークンを返しますが、GSS_Accept_秒_文脈()(_GSS_S COMPLETEの主要な_ステータスコードをもたらします)へのサーバの最終案内がどんなトークンも全く返さないなら、以下を送ります:
byte SSH_MSG_KEXGSS_COMPLETE
mpint f
string per_msg_token (MIC of H)
boolean FALSE
SSH_エムエスジー_KEXGSS_COMPLETE mpint fが_msg_トークン(HのMIC)論理演算子FALSE単位で結ぶバイト
Hutzelman, et al. Standards Track [Page 8] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[8ページ]。
If the client receives this message when no call to GSS_Init_sec_context() has yet resulted in a major_status code of GSS_S_COMPLETE, a protocol error has occurred and the key exchange MUST fail.
GSS_Init_秒_文脈()へのどんな呼び出しもまだ_GSS_S COMPLETEの主要な_ステータスコードをもたらしていないとき、クライアントがこのメッセージを受け取るなら、プロトコル誤りは発生しました、そして、主要な交換は失敗しなければなりません。
If either the client's call to GSS_Init_sec_context() or the server's call to GSS_Accept_sec_context() returns an error status and produces an output token (called an "error token"), then the following SHOULD be sent to convey the error information to the peer:
GSS_Init_秒_文脈()か次に、_秒_文脈()が出力トークン(「誤りトークン」と呼ばれる)をエラー状況と生産物に返すというGSS_Acceptへのサーバの要求、以下のSHOULDに、クライアントの呼び出しであるなら送って、エラー情報を同輩に伝えてください:
byte SSH_MSG_KEXGSS_CONTINUE
string error_token
バイトSSH_エムエスジー_KEXGSS_CONTINUEストリング誤り_トークン
If a server sends both this message and an SSH_MSG_KEXGSS_ERROR message, the SSH_MSG_KEXGSS_ERROR message MUST be sent first, to allow clients to record and/or display the error information before processing the error token. This is important because a client processing an error token will likely disconnect without reading any further messages.
サーバがこのメッセージとSSH_エムエスジー_KEXGSS_ERRORメッセージの両方を送るなら、最初に、誤りトークンを処理する前にクライアントがエラー情報を記録する、そして/または、表示するのを許容するためにSSH_エムエスジー_KEXGSS_ERRORメッセージを送らなければなりません。 誤りトークンを処理するクライアントがおそらくどんなさらなるメッセージも読まないで切断するので、これは重要です。
In the event of a GSS-API error on the server, the server MAY send the following message before terminating the connection:
サーバにおけるGSS-API誤りの場合、接続を終える前に、サーバは以下のメッセージを送るかもしれません:
byte SSH_MSG_KEXGSS_ERROR
uint32 major_status
uint32 minor_status
string message
string language tag
SSH_エムエスジー_KEXGSS_ERROR uint32少佐_状態uint32未成年者_状態ストリングメッセージストリング言語がタグ付けをするバイト
The message text MUST be encoded in the UTF-8 encoding described in [UTF8]. Language tags are those described in [LANGTAG]. Note that the message text may contain multiple lines separated by carriage return-line feed (CRLF) sequences. Application developers should take this into account when displaying these messages.
[UTF8]で説明されたUTF-8コード化でメッセージ・テキストをコード化しなければなりません。 言語タグは[LANGTAG]で説明されたものです。 メッセージ・テキストが復帰改行(CRLF)系列によって切り離された複数の系列を含むかもしれないことに注意してください。 これらのメッセージを表示するとき、アプリケーション開発者はこれを考慮に入れるべきです。
The hash H is computed as the HASH hash of the concatenation of the following:
ハッシュHは以下の連結のHASHハッシュとして計算されます:
string V_C, the client's version string (CR, NL excluded)
string V_S, the server's version string (CR, NL excluded)
string I_C, the payload of the client's SSH_MSG_KEXINIT
string I_S, the payload of the server's SSH_MSG_KEXINIT
string K_S, the host key
mpint e, exchange value sent by the client
mpint f, exchange value sent by the server
mpint K, the shared secret
V_Cを結んでください、クライアントのバージョンストリング(CR、除かれたNL)ストリングV_S、サーバのバージョンストリング(CR、除かれたNL)ストリングI_C、クライアントのSSH_エムエスジー_KEXINITストリングI_Sのペイロード、サーバのSSH_エムエスジー_KEXINITストリングK_Sのペイロード、ホストの主要なmpint e、クライアントmpint fによって送られた交換価値、サーバmpint K単位で送られた交換価値、共有秘密キー
Hutzelman, et al. Standards Track [Page 9] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[9ページ]。
This value is called the exchange hash, and it is used to authenticate the key exchange. The exchange hash SHOULD be kept secret. If no SSH_MSG_KEXGSS_HOSTKEY message has been sent by the server or received by the client, then the empty string is used in place of K_S when computing the exchange hash.
この値は交換ハッシュと呼ばれます、そして、それは、主要な交換を認証するのに使用されます。 交換はSHOULDを論じ尽くします。秘密にされてください。 交換ハッシュを計算するとき、SSH_エムエスジー_KEXGSS_HOSTKEYメッセージを全くサーバで送りもしませんし、クライアントが受け取ってもいないなら、K_Sに代わって空のストリングを使用します。
The GSS_GetMIC call MUST be applied over H, not the original data.
GSS_GetMIC呼び出しをオリジナルのデータではなく、Hの上に適用しなければなりません。
2.2. Group Exchange
2.2. グループ交換
This section describes a modification to the generic GSS-API- authenticated Diffie-Hellman key exchange to allow the negotiation of the group to be used, using a method based on that described in [GROUP-EXCHANGE].
このセクションはグループの交渉が使用されるのを許容するためにジェネリックGSS-APIで認証されたディフィー-ヘルマンの主要な交換に変更を説明します、[GROUP-EXCHANGE]で説明されたそれに基づくメソッドを使用して。
The server keeps a list of safe primes and corresponding generators that it can select from. These are chosen as described in Section 3 of [GROUP-EXCHANGE]. The client requests a modulus from the server, indicating the minimum, maximum, and preferred sizes; the server responds with a suitable modulus and generator. The exchange then proceeds as described in Section 2.1 above.
サーバはそれが選び抜くことができる安全な盛りと対応するジェネレータのリストを保ちます。 これらは[GROUP-EXCHANGE]のセクション3で説明されるように選ばれています。 最小の、そして、最大の、そして、都合のよいサイズを示して、クライアントはサーバから係数を要求します。 サーバは適当な係数とジェネレータで反応します。 そして、交換は上のセクション2.1で説明されるように続きます。
This description uses the following symbols, in addition to those defined above:
この記述は以下の上で定義されたものに加えて以下のシンボルを使用します。
o n is the size of the modulus p in bits that the client would like
to receive from the server
o nはクライアントがサーバから受け取りたがっているビットの係数pのサイズです。
o min and max are the minimal and maximal sizes of p in bits that
are acceptable to the client
o 分と最大はクライアントにとって、許容できるビットのpの最小量の、そして、最大限度のサイズです。
1. C sends "min || n || max" to S, indicating the minimal acceptable
group size, the preferred size of the group, and the maximal
group size in bits the client will accept.
1. Cは「分」を送ります。|| n|| クライアントは、S、最小量の許容できるグループサイズを示す、グループの優先サイズ、およびビットの最大限度のグループサイズへの「最大限にしてください。」と受け入れるでしょう。
2. S finds a group that best matches the client's request, and sends
"p || g" to C.
2. Sはクライアントの要求に最もよく合って、「p」を送るグループを見つけます。|| 「g」からC。
3. The exchange proceeds as described in Section 2.1 above,
beginning with step 1, except that the exchange hash is computed
as described below.
3. 交換は上のセクション2.1で説明されるように続きます、ステップ1で始まって、交換ハッシュが以下で説明されるように計算されるのを除いて。
Servers and clients SHOULD support groups with a modulus length of k bits, where 1024 <= k <= 8192. The recommended values for min and max are 1024 and 8192, respectively.
サーバと1024<がk<と等しいkビットの係数の長さがあるクライアントSHOULDサポートグループ=8192。 分と最大のための推奨値は、それぞれ1024と8192です。
This is implemented using the following messages, in addition to those described above:
以下の上で説明されたものに加えて以下のメッセージを使用するのはこれに実装されます。
Hutzelman, et al. Standards Track [Page 10] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman、他 規格はセキュアシェル (SSH)GSS-APIメソッド2006年5月にRFC4462を追跡します[10ページ]。
First, the client sends:
まず最初に、クライアントは発信します:
byte SSH_MSG_KEXGSS_GROUPREQ
uint32 min, minimal size in bits of an acceptable group
uint32 n, preferred size in bits of the group the server
should send
uint32 max, maximal size in bits of an acceptable group
バイトSSH_エムエスジー_KEXGSS_GROUPREQ uint32分、許容できるグループuint32 nのビットの最小量のサイズ、サーバが許容できるグループのビットでuint32最大、最大限度のサイズを送るべきであるグループのビットの優先サイズ
The server responds with:
サーバは以下で反応します。
byte SSH_MSG_KEXGSS_GROUP
mpint p, safe prime
mpint g, generator for subgroup in GF(p)
_バイトSSH_エムエスジーKEXGSS_GROUP mpint p、安全な主要なmpint g、GFにおけるサブグループのためのジェネレータ(p)
This is followed by the message exchange described above in Section 2.1, except that the exchange hash H is computed as the HASH hash of the concatenation of the following:
セクション2.1で上で説明された交換処理はこれのあとに続いています、交換ハッシュHが以下の連結のHASHハッシュとして計算されるのを除いて:
string V_C, the client's version string (CR, NL excluded)
string V_S, the server's version string (CR, NL excluded)
string I_C, the payload of the client's SSH_MSG_KEXINIT
string I_S, the payload of the server's SSH_MSG_KEXINIT
string K_S, the host key
uint32 min, minimal size in bits of an acceptable group
uint32 n, preferred size in bits of the group the server
should send
uint32 max, maximal size in bits of an acceptable group
mpint p, safe prime
mpint g, generator for subgroup in GF(p)
mpint e, exchange value sent by the client
mpint f, exchange value sent by the server
mpint K, the shared secret
string V_C, the client's version string (CR, NL excluded) string V_S, the server's version string (CR, NL excluded) string I_C, the payload of the client's SSH_MSG_KEXINIT string I_S, the payload of the server's SSH_MSG_KEXINIT string K_S, the host key uint32 min, minimal size in bits of an acceptable group uint32 n, preferred size in bits of the group the server should send uint32 max, maximal size in bits of an acceptable group mpint p, safe prime mpint g, generator for subgroup in GF(p) mpint e, exchange value sent by the client mpint f, exchange value sent by the server mpint K, the shared secret
2.3. gss-group1-sha1-*
2.3. gss-group1-sha1-*
Each of these methods specifies GSS-API-authenticated Diffie-Hellman key exchange as described in Section 2.1 with SHA-1 as HASH, and the group defined in Section 8.1 of [SSH-TRANSPORT]. The method name for each method is the concatenation of the string "gss-group1-sha1-" with the Base64 encoding of the MD5 hash [MD5] of the ASN.1 Distinguished Encoding Rules (DER) encoding [ASN1] of the underlying GSS-API mechanism's Object Identifier (OID). Base64 encoding is described in Section 6.8 of [MIME].
Each of these methods specifies GSS-API-authenticated Diffie-Hellman key exchange as described in Section 2.1 with SHA-1 as HASH, and the group defined in Section 8.1 of [SSH-TRANSPORT]. The method name for each method is the concatenation of the string "gss-group1-sha1-" with the Base64 encoding of the MD5 hash [MD5] of the ASN.1 Distinguished Encoding Rules (DER) encoding [ASN1] of the underlying GSS-API mechanism's Object Identifier (OID). Base64 encoding is described in Section 6.8 of [MIME].
Each and every such key exchange method is implicitly registered by this specification. The IESG is considered to be the owner of all such key exchange methods; this does NOT imply that the IESG is considered to be the owner of the underlying GSS-API mechanism.
Each and every such key exchange method is implicitly registered by this specification. The IESG is considered to be the owner of all such key exchange methods; this does NOT imply that the IESG is considered to be the owner of the underlying GSS-API mechanism.
Hutzelman, et al. Standards Track [Page 11] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 11] RFC 4462 SSH GSS-API Methods May 2006
2.4. gss-group14-sha1-*
2.4. gss-group14-sha1-*
Each of these methods specifies GSS-API authenticated Diffie-Hellman key exchange as described in Section 2.1 with SHA-1 as HASH, and the group defined in Section 8.2 of [SSH-TRANSPORT]. The method name for each method is the concatenation of the string "gss-group14-sha1-" with the Base64 encoding of the MD5 hash [MD5] of the ASN.1 DER encoding [ASN1] of the underlying GSS-API mechanism's OID. Base64 encoding is described in Section 6.8 of [MIME].
Each of these methods specifies GSS-API authenticated Diffie-Hellman key exchange as described in Section 2.1 with SHA-1 as HASH, and the group defined in Section 8.2 of [SSH-TRANSPORT]. The method name for each method is the concatenation of the string "gss-group14-sha1-" with the Base64 encoding of the MD5 hash [MD5] of the ASN.1 DER encoding [ASN1] of the underlying GSS-API mechanism's OID. Base64 encoding is described in Section 6.8 of [MIME].
Each and every such key exchange method is implicitly registered by this specification. The IESG is considered to be the owner of all such key exchange methods; this does NOT imply that the IESG is considered to be the owner of the underlying GSS-API mechanism.
Each and every such key exchange method is implicitly registered by this specification. The IESG is considered to be the owner of all such key exchange methods; this does NOT imply that the IESG is considered to be the owner of the underlying GSS-API mechanism.
2.5. gss-gex-sha1-*
2.5. gss-gex-sha1-*
Each of these methods specifies GSS-API-authenticated Diffie-Hellman key exchange as described in Section 2.2 with SHA-1 as HASH. The method name for each method is the concatenation of the string "gss- gex-sha1-" with the Base64 encoding of the MD5 hash [MD5] of the ASN.1 DER encoding [ASN1] of the underlying GSS-API mechanism's OID. Base64 encoding is described in Section 6.8 of [MIME].
Each of these methods specifies GSS-API-authenticated Diffie-Hellman key exchange as described in Section 2.2 with SHA-1 as HASH. The method name for each method is the concatenation of the string "gss- gex-sha1-" with the Base64 encoding of the MD5 hash [MD5] of the ASN.1 DER encoding [ASN1] of the underlying GSS-API mechanism's OID. Base64 encoding is described in Section 6.8 of [MIME].
Each and every such key exchange method is implicitly registered by this specification. The IESG is considered to be the owner of all such key exchange methods; this does NOT imply that the IESG is considered to be the owner of the underlying GSS-API mechanism.
Each and every such key exchange method is implicitly registered by this specification. The IESG is considered to be the owner of all such key exchange methods; this does NOT imply that the IESG is considered to be the owner of the underlying GSS-API mechanism.
2.6. Other GSS-API Key Exchange Methods
2.6. Other GSS-API Key Exchange Methods
Key exchange method names starting with "gss-" are reserved for key exchange methods that conform to this document; in particular, for those methods that use the GSS-API-authenticated Diffie-Hellman key exchange algorithm described in Section 2.1, including any future methods that use different groups and/or hash functions. The intent is that the names for any such future methods be defined in a similar manner to that used in Section 2.3.
Key exchange method names starting with "gss-" are reserved for key exchange methods that conform to this document; in particular, for those methods that use the GSS-API-authenticated Diffie-Hellman key exchange algorithm described in Section 2.1, including any future methods that use different groups and/or hash functions. The intent is that the names for any such future methods be defined in a similar manner to that used in Section 2.3.
Hutzelman, et al. Standards Track [Page 12] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 12] RFC 4462 SSH GSS-API Methods May 2006
3. GSS-API User Authentication
3. GSS-API User Authentication
This section describes a general-purpose user authentication method based on [GSSAPI]. It is intended to be run over the SSH user authentication protocol [SSH-USERAUTH].
This section describes a general-purpose user authentication method based on [GSSAPI]. It is intended to be run over the SSH user authentication protocol [SSH-USERAUTH].
The authentication method name for this protocol is "gssapi-with- mic".
The authentication method name for this protocol is "gssapi-with- mic".
3.1. GSS-API Authentication Overview
3.1. GSS-API Authentication Overview
GSS-API authentication must maintain a context. Authentication begins when the client sends an SSH_MSG_USERAUTH_REQUEST, which specifies the mechanism OIDs the client supports.
GSS-API authentication must maintain a context. Authentication begins when the client sends an SSH_MSG_USERAUTH_REQUEST, which specifies the mechanism OIDs the client supports.
If the server supports any of the requested mechanism OIDs, the server sends an SSH_MSG_USERAUTH_GSSAPI_RESPONSE message containing the mechanism OID.
If the server supports any of the requested mechanism OIDs, the server sends an SSH_MSG_USERAUTH_GSSAPI_RESPONSE message containing the mechanism OID.
After the client receives SSH_MSG_USERAUTH_GSSAPI_RESPONSE, the client and server exchange SSH_MSG_USERAUTH_GSSAPI_TOKEN packets until the authentication mechanism either succeeds or fails.
After the client receives SSH_MSG_USERAUTH_GSSAPI_RESPONSE, the client and server exchange SSH_MSG_USERAUTH_GSSAPI_TOKEN packets until the authentication mechanism either succeeds or fails.
If at any time during the exchange the client sends a new SSH_MSG_USERAUTH_REQUEST packet, the GSS-API context is completely discarded and destroyed, and any further GSS-API authentication MUST restart from the beginning.
If at any time during the exchange the client sends a new SSH_MSG_USERAUTH_REQUEST packet, the GSS-API context is completely discarded and destroyed, and any further GSS-API authentication MUST restart from the beginning.
If the authentication succeeds and a non-empty user name is presented by the client, the SSH server implementation verifies that the user name is authorized based on the credentials exchanged in the GSS-API exchange. If the user name is not authorized, then the authentication MUST fail.
If the authentication succeeds and a non-empty user name is presented by the client, the SSH server implementation verifies that the user name is authorized based on the credentials exchanged in the GSS-API exchange. If the user name is not authorized, then the authentication MUST fail.
3.2. Initiating GSS-API Authentication
3.2. Initiating GSS-API Authentication
The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST:
The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST:
byte SSH_MSG_USERAUTH_REQUEST
string user name (in ISO-10646 UTF-8 encoding)
string service name (in US-ASCII)
string "gssapi-with-mic" (US-ASCII method name)
uint32 n, the number of mechanism OIDs client supports
string[n] mechanism OIDs
byte SSH_MSG_USERAUTH_REQUEST string user name (in ISO-10646 UTF-8 encoding) string service name (in US-ASCII) string "gssapi-with-mic" (US-ASCII method name) uint32 n, the number of mechanism OIDs client supports string[n] mechanism OIDs
Mechanism OIDs are encoded according to the ASN.1 Distinguished Encoding Rules (DER), as described in [ASN1] and in Section 3.1 of
Mechanism OIDs are encoded according to the ASN.1 Distinguished Encoding Rules (DER), as described in [ASN1] and in Section 3.1 of
Hutzelman, et al. Standards Track [Page 13] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 13] RFC 4462 SSH GSS-API Methods May 2006
[GSSAPI]. The mechanism OIDs MUST be listed in order of preference, and the server must choose the first mechanism OID on the list that it supports.
[GSSAPI]. The mechanism OIDs MUST be listed in order of preference, and the server must choose the first mechanism OID on the list that it supports.
The client SHOULD send GSS-API mechanism OIDs only for mechanisms that are of the same priority, compared to non-GSS-API authentication methods. Otherwise, authentication methods may be executed out of order. Thus, the client could first send an SSH_MSG_USERAUTH_REQUEST for one GSS-API mechanism, then try public key authentication, and then try another GSS-API mechanism.
The client SHOULD send GSS-API mechanism OIDs only for mechanisms that are of the same priority, compared to non-GSS-API authentication methods. Otherwise, authentication methods may be executed out of order. Thus, the client could first send an SSH_MSG_USERAUTH_REQUEST for one GSS-API mechanism, then try public key authentication, and then try another GSS-API mechanism.
If the server does not support any of the specified OIDs, the server MUST fail the request by sending an SSH_MSG_USERAUTH_FAILURE packet.
If the server does not support any of the specified OIDs, the server MUST fail the request by sending an SSH_MSG_USERAUTH_FAILURE packet.
The user name may be an empty string if it can be deduced from the results of the GSS-API authentication. If the user name is not empty, and the requested user does not exist, the server MAY disconnect or MAY send a bogus list of acceptable authentications but never accept any. This makes it possible for the server to avoid disclosing information about which accounts exist. In any case, if the user does not exist, the authentication request MUST NOT be accepted.
The user name may be an empty string if it can be deduced from the results of the GSS-API authentication. If the user name is not empty, and the requested user does not exist, the server MAY disconnect or MAY send a bogus list of acceptable authentications but never accept any. This makes it possible for the server to avoid disclosing information about which accounts exist. In any case, if the user does not exist, the authentication request MUST NOT be accepted.
Note that the 'user name' value is encoded in ISO-10646 UTF-8. It is up to the server how it interprets the user name and determines whether the client is authorized based on his GSS-API credentials. In particular, the encoding used by the system for user names is a matter for the ssh server implementation. However, if the client reads the user name in some other encoding (e.g., ISO 8859-1 - ISO Latin1), it MUST convert the user name to ISO-10646 UTF-8 before transmitting, and the server MUST convert the user name to the encoding used on that system for user names.
Note that the 'user name' value is encoded in ISO-10646 UTF-8. It is up to the server how it interprets the user name and determines whether the client is authorized based on his GSS-API credentials. In particular, the encoding used by the system for user names is a matter for the ssh server implementation. However, if the client reads the user name in some other encoding (e.g., ISO 8859-1 - ISO Latin1), it MUST convert the user name to ISO-10646 UTF-8 before transmitting, and the server MUST convert the user name to the encoding used on that system for user names.
Any normalization or other preparation of names is done by the ssh server based on the requirements of the system, and is outside the scope of SSH. SSH implementations which maintain private user databases SHOULD prepare user names as described by [SASLPREP].
Any normalization or other preparation of names is done by the ssh server based on the requirements of the system, and is outside the scope of SSH. SSH implementations which maintain private user databases SHOULD prepare user names as described by [SASLPREP].
The client MAY at any time continue with a new SSH_MSG_USERAUTH_REQUEST message, in which case the server MUST abandon the previous authentication attempt and continue with the new one.
The client MAY at any time continue with a new SSH_MSG_USERAUTH_REQUEST message, in which case the server MUST abandon the previous authentication attempt and continue with the new one.
3.3. Initial Server Response
3.3. Initial Server Response
The server responds to the SSH_MSG_USERAUTH_REQUEST with either an SSH_MSG_USERAUTH_FAILURE if none of the mechanisms are supported or with an SSH_MSG_USERAUTH_GSSAPI_RESPONSE as follows:
The server responds to the SSH_MSG_USERAUTH_REQUEST with either an SSH_MSG_USERAUTH_FAILURE if none of the mechanisms are supported or with an SSH_MSG_USERAUTH_GSSAPI_RESPONSE as follows:
Hutzelman, et al. Standards Track [Page 14] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 14] RFC 4462 SSH GSS-API Methods May 2006
byte SSH_MSG_USERAUTH_GSSAPI_RESPONSE
string selected mechanism OID
byte SSH_MSG_USERAUTH_GSSAPI_RESPONSE string selected mechanism OID
The mechanism OID must be one of the OIDs sent by the client in the SSH_MSG_USERAUTH_REQUEST packet.
The mechanism OID must be one of the OIDs sent by the client in the SSH_MSG_USERAUTH_REQUEST packet.
3.4. GSS-API Session
3.4. GSS-API Session
Once the mechanism OID has been selected, the client will then initiate an exchange of one or more pairs of SSH_MSG_USERAUTH_GSSAPI_TOKEN packets. These packets contain the tokens produced from the 'GSS_Init_sec_context()' and 'GSS_Accept_sec_context()' calls. The actual number of packets exchanged is determined by the underlying GSS-API mechanism.
Once the mechanism OID has been selected, the client will then initiate an exchange of one or more pairs of SSH_MSG_USERAUTH_GSSAPI_TOKEN packets. These packets contain the tokens produced from the 'GSS_Init_sec_context()' and 'GSS_Accept_sec_context()' calls. The actual number of packets exchanged is determined by the underlying GSS-API mechanism.
byte SSH_MSG_USERAUTH_GSSAPI_TOKEN
string data returned from either GSS_Init_sec_context()
or GSS_Accept_sec_context()
byte SSH_MSG_USERAUTH_GSSAPI_TOKEN string data returned from either GSS_Init_sec_context() or GSS_Accept_sec_context()
If an error occurs during this exchange on server side, the server can terminate the method by sending an SSH_MSG_USERAUTH_FAILURE packet. If an error occurs on client side, the client can terminate the method by sending a new SSH_MSG_USERAUTH_REQUEST packet.
If an error occurs during this exchange on server side, the server can terminate the method by sending an SSH_MSG_USERAUTH_FAILURE packet. If an error occurs on client side, the client can terminate the method by sending a new SSH_MSG_USERAUTH_REQUEST packet.
When calling GSS_Init_sec_context(), the client MUST set integ_req_flag to "true" to request that per-message integrity protection be supported for this context. In addition, deleg_req_flag MAY be set to "true" to request access delegation, if requested by the user.
When calling GSS_Init_sec_context(), the client MUST set integ_req_flag to "true" to request that per-message integrity protection be supported for this context. In addition, deleg_req_flag MAY be set to "true" to request access delegation, if requested by the user.
Since the user authentication process by its nature authenticates only the client, the setting of mutual_req_flag is not needed for this process. This flag SHOULD be set to "false".
Since the user authentication process by its nature authenticates only the client, the setting of mutual_req_flag is not needed for this process. This flag SHOULD be set to "false".
Since the user authentication process will involve the exchange of only a single token once the context has been established, it is not necessary that the context support detection of replayed or out-of- sequence tokens. Thus, the setting of replay_det_req_flag and sequence_req_flag are not needed for this process. These flags SHOULD be set to "false".
Since the user authentication process will involve the exchange of only a single token once the context has been established, it is not necessary that the context support detection of replayed or out-of- sequence tokens. Thus, the setting of replay_det_req_flag and sequence_req_flag are not needed for this process. These flags SHOULD be set to "false".
Additional SSH_MSG_USERAUTH_GSSAPI_TOKEN messages are sent if and only if the calls to the GSS-API routines produce send tokens of non- zero length.
Additional SSH_MSG_USERAUTH_GSSAPI_TOKEN messages are sent if and only if the calls to the GSS-API routines produce send tokens of non- zero length.
Any major status code other than GSS_S_COMPLETE or GSS_S_CONTINUE_NEEDED SHOULD be a failure.
Any major status code other than GSS_S_COMPLETE or GSS_S_CONTINUE_NEEDED SHOULD be a failure.
Hutzelman, et al. Standards Track [Page 15] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 15] RFC 4462 SSH GSS-API Methods May 2006
3.5. Binding Encryption Keys
3.5. Binding Encryption Keys
In some cases, it is possible to obtain improved security by allowing access only if the client sends a valid message integrity code (MIC) binding the GSS-API context to the keys used for encryption and integrity protection of the SSH session. With this extra level of protection, a "man-in-the-middle" attacker who has convinced a client of his authenticity cannot then relay user authentication messages between the real client and server, thus gaining access to the real server. This additional protection is available when the negotiated GSS-API context supports per-message integrity protection, as indicated by the setting of the integ_avail flag on successful return from GSS_Init_sec_context() or GSS_Accept_sec_context().
In some cases, it is possible to obtain improved security by allowing access only if the client sends a valid message integrity code (MIC) binding the GSS-API context to the keys used for encryption and integrity protection of the SSH session. With this extra level of protection, a "man-in-the-middle" attacker who has convinced a client of his authenticity cannot then relay user authentication messages between the real client and server, thus gaining access to the real server. This additional protection is available when the negotiated GSS-API context supports per-message integrity protection, as indicated by the setting of the integ_avail flag on successful return from GSS_Init_sec_context() or GSS_Accept_sec_context().
When the client's call to GSS_Init_sec_context() returns GSS_S_COMPLETE with the integ_avail flag set, the client MUST conclude the user authentication exchange by sending the following message:
When the client's call to GSS_Init_sec_context() returns GSS_S_COMPLETE with the integ_avail flag set, the client MUST conclude the user authentication exchange by sending the following message:
byte SSH_MSG_USERAUTH_GSSAPI_MIC
string MIC
byte SSH_MSG_USERAUTH_GSSAPI_MIC string MIC
This message MUST be sent only if GSS_Init_sec_context() returned GSS_S_COMPLETE. If a token is also returned, then the SSH_MSG_USERAUTH_GSSAPI_TOKEN message MUST be sent before this one.
This message MUST be sent only if GSS_Init_sec_context() returned GSS_S_COMPLETE. If a token is also returned, then the SSH_MSG_USERAUTH_GSSAPI_TOKEN message MUST be sent before this one.
The contents of the MIC field are obtained by calling GSS_GetMIC() over the following, using the GSS-API context that was just established:
The contents of the MIC field are obtained by calling GSS_GetMIC() over the following, using the GSS-API context that was just established:
string session identifier
byte SSH_MSG_USERAUTH_REQUEST
string user name
string service
string "gssapi-with-mic"
string session identifier byte SSH_MSG_USERAUTH_REQUEST string user name string service string "gssapi-with-mic"
If this message is received by the server before the GSS-API context is fully established, the server MUST fail the authentication.
If this message is received by the server before the GSS-API context is fully established, the server MUST fail the authentication.
If this message is received by the server when the negotiated GSS-API context does not support per-message integrity protection, the server MUST fail the authentication.
If this message is received by the server when the negotiated GSS-API context does not support per-message integrity protection, the server MUST fail the authentication.
3.6. Client Acknowledgement
3.6. Client Acknowledgement
Some servers may wish to permit user authentication to proceed even when the negotiated GSS-API context does not support per-message integrity protection. In such cases, it is possible for the server
Some servers may wish to permit user authentication to proceed even when the negotiated GSS-API context does not support per-message integrity protection. In such cases, it is possible for the server
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Hutzelman, et al. Standards Track [Page 16] RFC 4462 SSH GSS-API Methods May 2006
to successfully complete the GSS-API method, while the client's last call to GSS_Init_sec_context() fails. If the server simply assumed success on the part of the client and completed the authentication service, it is possible that the client would fail to complete the authentication method, but not be able to retry other methods because the server had already moved on. To protect against this, a final message is sent by the client to indicate it has completed authentication.
to successfully complete the GSS-API method, while the client's last call to GSS_Init_sec_context() fails. If the server simply assumed success on the part of the client and completed the authentication service, it is possible that the client would fail to complete the authentication method, but not be able to retry other methods because the server had already moved on. To protect against this, a final message is sent by the client to indicate it has completed authentication.
When the client's call to GSS_Init_sec_context() returns GSS_S_COMPLETE with the integ_avail flag not set, the client MUST conclude the user authentication exchange by sending the following message:
When the client's call to GSS_Init_sec_context() returns GSS_S_COMPLETE with the integ_avail flag not set, the client MUST conclude the user authentication exchange by sending the following message:
byte SSH_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE
byte SSH_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE
This message MUST be sent only if GSS_Init_sec_context() returned GSS_S_COMPLETE. If a token is also returned, then the SSH_MSG_USERAUTH_GSSAPI_TOKEN message MUST be sent before this one.
This message MUST be sent only if GSS_Init_sec_context() returned GSS_S_COMPLETE. If a token is also returned, then the SSH_MSG_USERAUTH_GSSAPI_TOKEN message MUST be sent before this one.
If this message is received by the server before the GSS-API context is fully established, the server MUST fail the authentication.
If this message is received by the server before the GSS-API context is fully established, the server MUST fail the authentication.
If this message is received by the server when the negotiated GSS-API context supports per-message integrity protection, the server MUST fail the authentication.
If this message is received by the server when the negotiated GSS-API context supports per-message integrity protection, the server MUST fail the authentication.
It is a site policy decision for the server whether or not to permit authentication using GSS-API mechanisms and/or contexts that do not support per-message integrity protection. The server MAY fail the otherwise valid gssapi-with-mic authentication if per-message integrity protection is not supported.
It is a site policy decision for the server whether or not to permit authentication using GSS-API mechanisms and/or contexts that do not support per-message integrity protection. The server MAY fail the otherwise valid gssapi-with-mic authentication if per-message integrity protection is not supported.
3.7. Completion
3.7. Completion
As with all SSH authentication methods, successful completion is indicated by an SSH_MSG_USERAUTH_SUCCESS if no other authentication is required, or an SSH_MSG_USERAUTH_FAILURE with the partial success flag set if the server requires further authentication. This packet SHOULD be sent immediately following receipt of the SSH_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE packet.
As with all SSH authentication methods, successful completion is indicated by an SSH_MSG_USERAUTH_SUCCESS if no other authentication is required, or an SSH_MSG_USERAUTH_FAILURE with the partial success flag set if the server requires further authentication. This packet SHOULD be sent immediately following receipt of the SSH_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE packet.
3.8. Error Status
3.8. Error Status
In the event that a GSS-API error occurs on the server during context establishment, the server MAY send the following message to inform the client of the details of the error before sending an SSH_MSG_USERAUTH_FAILURE message:
In the event that a GSS-API error occurs on the server during context establishment, the server MAY send the following message to inform the client of the details of the error before sending an SSH_MSG_USERAUTH_FAILURE message:
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Hutzelman, et al. Standards Track [Page 17] RFC 4462 SSH GSS-API Methods May 2006
byte SSH_MSG_USERAUTH_GSSAPI_ERROR
uint32 major_status
uint32 minor_status
string message
string language tag
byte SSH_MSG_USERAUTH_GSSAPI_ERROR uint32 major_status uint32 minor_status string message string language tag
The message text MUST be encoded in the UTF-8 encoding described in [UTF8]. Language tags are those described in [LANGTAG]. Note that the message text may contain multiple lines separated by carriage return-line feed (CRLF) sequences. Application developers should take this into account when displaying these messages.
The message text MUST be encoded in the UTF-8 encoding described in [UTF8]. Language tags are those described in [LANGTAG]. Note that the message text may contain multiple lines separated by carriage return-line feed (CRLF) sequences. Application developers should take this into account when displaying these messages.
Clients receiving this message MAY log the error details and/or report them to the user. Any server sending this message MUST ignore any SSH_MSG_UNIMPLEMENTED sent by the client in response.
Clients receiving this message MAY log the error details and/or report them to the user. Any server sending this message MUST ignore any SSH_MSG_UNIMPLEMENTED sent by the client in response.
3.9. Error Token
3.9. Error Token
In the event that, during context establishment, a client's call to GSS_Init_sec_context() or a server's call to GSS_Accept_sec_context() returns a token along with an error status, the resulting "error token" SHOULD be sent to the peer using the following message:
In the event that, during context establishment, a client's call to GSS_Init_sec_context() or a server's call to GSS_Accept_sec_context() returns a token along with an error status, the resulting "error token" SHOULD be sent to the peer using the following message:
byte SSH_MSG_USERAUTH_GSSAPI_ERRTOK
string error token
byte SSH_MSG_USERAUTH_GSSAPI_ERRTOK string error token
This message implies that the authentication is about to fail, and is defined to allow the error token to be communicated without losing synchronization.
This message implies that the authentication is about to fail, and is defined to allow the error token to be communicated without losing synchronization.
When a server sends this message, it MUST be followed by an SSH_MSG_USERAUTH_FAILURE message, which is to be interpreted as applying to the same authentication request. A client receiving this message SHOULD wait for the following SSH_MSG_USERAUTH_FAILURE message before beginning another authentication attempt.
When a server sends this message, it MUST be followed by an SSH_MSG_USERAUTH_FAILURE message, which is to be interpreted as applying to the same authentication request. A client receiving this message SHOULD wait for the following SSH_MSG_USERAUTH_FAILURE message before beginning another authentication attempt.
When a client sends this message, it MUST be followed by a new authentication request or by terminating the connection. A server receiving this message MUST NOT send an SSH_MSG_USERAUTH_FAILURE in reply, since such a message might otherwise be interpreted by a client as a response to the following authentication sequence.
When a client sends this message, it MUST be followed by a new authentication request or by terminating the connection. A server receiving this message MUST NOT send an SSH_MSG_USERAUTH_FAILURE in reply, since such a message might otherwise be interpreted by a client as a response to the following authentication sequence.
Any server sending this message MUST ignore any SSH_MSG_UNIMPLEMENTED sent by the client in response. If a server sends both this message and an SSH_MSG_USERAUTH_GSSAPI_ERROR message, the SSH_MSG_USERAUTH_GSSAPI_ERROR message MUST be sent first, to allow the client to store and/or display the error status before processing the error token.
Any server sending this message MUST ignore any SSH_MSG_UNIMPLEMENTED sent by the client in response. If a server sends both this message and an SSH_MSG_USERAUTH_GSSAPI_ERROR message, the SSH_MSG_USERAUTH_GSSAPI_ERROR message MUST be sent first, to allow the client to store and/or display the error status before processing the error token.
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Hutzelman, et al. Standards Track [Page 18] RFC 4462 SSH GSS-API Methods May 2006
4. Authentication Using GSS-API Key Exchange
4. Authentication Using GSS-API Key Exchange
This section describes a user authentication method building on the framework described in [SSH-USERAUTH]. This method performs user authentication by making use of an existing GSS-API context established during key exchange.
This section describes a user authentication method building on the framework described in [SSH-USERAUTH]. This method performs user authentication by making use of an existing GSS-API context established during key exchange.
The authentication method name for this protocol is "gssapi-keyex".
The authentication method name for this protocol is "gssapi-keyex".
This method may be used only if the initial key exchange was performed using a GSS-API-based key exchange method defined in accordance with Section 2. The GSS-API context used with this method is always that established during an initial GSS-API-based key exchange. Any context established during key exchange for the purpose of rekeying MUST NOT be used with this method.
This method may be used only if the initial key exchange was performed using a GSS-API-based key exchange method defined in accordance with Section 2. The GSS-API context used with this method is always that established during an initial GSS-API-based key exchange. Any context established during key exchange for the purpose of rekeying MUST NOT be used with this method.
The server SHOULD include this user authentication method in the list of methods that can continue (in an SSH_MSG_USERAUTH_FAILURE) if the initial key exchange was performed using a GSS-API-based key exchange method and provides information about the user's identity that is useful to the server. It MUST NOT include this method if the initial key exchange was not performed using a GSS-API-based key exchange method defined in accordance with Section 2.
The server SHOULD include this user authentication method in the list of methods that can continue (in an SSH_MSG_USERAUTH_FAILURE) if the initial key exchange was performed using a GSS-API-based key exchange method and provides information about the user's identity that is useful to the server. It MUST NOT include this method if the initial key exchange was not performed using a GSS-API-based key exchange method defined in accordance with Section 2.
The client SHOULD attempt to use this method if it is advertised by the server, initial key exchange was performed using a GSS-API-based key exchange method, and this method has not already been tried. The client SHOULD NOT try this method more than once per session. It MUST NOT try this method if initial key exchange was not performed using a GSS-API-based key exchange method defined in accordance with Section 2.
The client SHOULD attempt to use this method if it is advertised by the server, initial key exchange was performed using a GSS-API-based key exchange method, and this method has not already been tried. The client SHOULD NOT try this method more than once per session. It MUST NOT try this method if initial key exchange was not performed using a GSS-API-based key exchange method defined in accordance with Section 2.
If a server receives a request for this method when initial key exchange was not performed using a GSS-API-based key exchange method defined in accordance with Section 2, it MUST return SSH_MSG_USERAUTH_FAILURE.
If a server receives a request for this method when initial key exchange was not performed using a GSS-API-based key exchange method defined in accordance with Section 2, it MUST return SSH_MSG_USERAUTH_FAILURE.
This method is defined as a single message:
This method is defined as a single message:
byte SSH_MSG_USERAUTH_REQUEST
string user name
string service
string "gssapi-keyex"
string MIC
byte SSH_MSG_USERAUTH_REQUEST string user name string service string "gssapi-keyex" string MIC
The contents of the MIC field are obtained by calling GSS_GetMIC over the following, using the GSS-API context that was established during initial key exchange:
The contents of the MIC field are obtained by calling GSS_GetMIC over the following, using the GSS-API context that was established during initial key exchange:
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Hutzelman, et al. Standards Track [Page 19] RFC 4462 SSH GSS-API Methods May 2006
string session identifier
byte SSH_MSG_USERAUTH_REQUEST
string user name
string service
string "gssapi-keyex"
string session identifier byte SSH_MSG_USERAUTH_REQUEST string user name string service string "gssapi-keyex"
Upon receiving this message when initial key exchange was performed using a GSS-API-based key exchange method, the server uses GSS_VerifyMIC() to verify that the MIC received is valid. If the MIC is not valid, the user authentication fails, and the server MUST return SSH_MSG_USERAUTH_FAILURE.
Upon receiving this message when initial key exchange was performed using a GSS-API-based key exchange method, the server uses GSS_VerifyMIC() to verify that the MIC received is valid. If the MIC is not valid, the user authentication fails, and the server MUST return SSH_MSG_USERAUTH_FAILURE.
If the MIC is valid and the server is satisfied as to the user's credentials, it MAY return either SSH_MSG_USERAUTH_SUCCESS or SSH_MSG_USERAUTH_FAILURE with the partial success flag set, depending on whether additional authentications are needed.
If the MIC is valid and the server is satisfied as to the user's credentials, it MAY return either SSH_MSG_USERAUTH_SUCCESS or SSH_MSG_USERAUTH_FAILURE with the partial success flag set, depending on whether additional authentications are needed.
5. Null Host Key Algorithm
5. Null Host Key Algorithm
The "null" host key algorithm has no associated host key material and provides neither signature nor encryption algorithms. Thus, it can be used only with key exchange methods that do not require any public-key operations and do not require the use of host public key material. The key exchange methods described in Section 2 are examples of such methods.
The "null" host key algorithm has no associated host key material and provides neither signature nor encryption algorithms. Thus, it can be used only with key exchange methods that do not require any public-key operations and do not require the use of host public key material. The key exchange methods described in Section 2 are examples of such methods.
This algorithm is used when, as a matter of configuration, the host does not have or does not wish to use a public key. For example, it can be used when the administrator has decided as a matter of policy to require that all key exchanges be authenticated using Kerberos [KRB5], and thus the only permitted key exchange method is the GSS-API-authenticated Diffie-Hellman exchange described above, with Kerberos V5 as the underlying GSS-API mechanism. In such a configuration, the server implementation supports the "ssh-dss" key algorithm (as required by [SSH-TRANSPORT]), but could be prohibited by configuration from using it. In this situation, the server needs some key exchange algorithm to advertise; the "null" algorithm fills this purpose.
This algorithm is used when, as a matter of configuration, the host does not have or does not wish to use a public key. For example, it can be used when the administrator has decided as a matter of policy to require that all key exchanges be authenticated using Kerberos [KRB5], and thus the only permitted key exchange method is the GSS-API-authenticated Diffie-Hellman exchange described above, with Kerberos V5 as the underlying GSS-API mechanism. In such a configuration, the server implementation supports the "ssh-dss" key algorithm (as required by [SSH-TRANSPORT]), but could be prohibited by configuration from using it. In this situation, the server needs some key exchange algorithm to advertise; the "null" algorithm fills this purpose.
Note that the use of the "null" algorithm in this way means that the server will not be able to interoperate with clients that do not support this algorithm. This is not a significant problem, since in the configuration described, it will also be unable to interoperate with implementations that do not support the GSS-API-authenticated key exchange and Kerberos.
Note that the use of the "null" algorithm in this way means that the server will not be able to interoperate with clients that do not support this algorithm. This is not a significant problem, since in the configuration described, it will also be unable to interoperate with implementations that do not support the GSS-API-authenticated key exchange and Kerberos.
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Hutzelman, et al. Standards Track [Page 20] RFC 4462 SSH GSS-API Methods May 2006
Any implementation supporting at least one key exchange method that conforms to Section 2 MUST also support the "null" host key algorithm. Servers MUST NOT advertise the "null" host key algorithm unless it is the only algorithm advertised.
Any implementation supporting at least one key exchange method that conforms to Section 2 MUST also support the "null" host key algorithm. Servers MUST NOT advertise the "null" host key algorithm unless it is the only algorithm advertised.
6. Summary of Message Numbers
6. Summary of Message Numbers
The following message numbers have been defined for use with GSS- API-based key exchange methods:
The following message numbers have been defined for use with GSS- API-based key exchange methods:
#define SSH_MSG_KEXGSS_INIT 30
#define SSH_MSG_KEXGSS_CONTINUE 31
#define SSH_MSG_KEXGSS_COMPLETE 32
#define SSH_MSG_KEXGSS_HOSTKEY 33
#define SSH_MSG_KEXGSS_ERROR 34
#define SSH_MSG_KEXGSS_GROUPREQ 40
#define SSH_MSG_KEXGSS_GROUP 41
#define SSH_MSG_KEXGSS_INIT 30 #define SSH_MSG_KEXGSS_CONTINUE 31 #define SSH_MSG_KEXGSS_COMPLETE 32 #define SSH_MSG_KEXGSS_HOSTKEY 33 #define SSH_MSG_KEXGSS_ERROR 34 #define SSH_MSG_KEXGSS_GROUPREQ 40 #define SSH_MSG_KEXGSS_GROUP 41
The numbers 30-49 are specific to key exchange and may be redefined by other kex methods.
The numbers 30-49 are specific to key exchange and may be redefined by other kex methods.
The following message numbers have been defined for use with the 'gssapi-with-mic' user authentication method:
The following message numbers have been defined for use with the 'gssapi-with-mic' user authentication method:
#define SSH_MSG_USERAUTH_GSSAPI_RESPONSE 60
#define SSH_MSG_USERAUTH_GSSAPI_TOKEN 61
#define SSH_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE 63
#define SSH_MSG_USERAUTH_GSSAPI_ERROR 64
#define SSH_MSG_USERAUTH_GSSAPI_ERRTOK 65
#define SSH_MSG_USERAUTH_GSSAPI_MIC 66
#define SSH_MSG_USERAUTH_GSSAPI_RESPONSE 60 #define SSH_MSG_USERAUTH_GSSAPI_TOKEN 61 #define SSH_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE 63 #define SSH_MSG_USERAUTH_GSSAPI_ERROR 64 #define SSH_MSG_USERAUTH_GSSAPI_ERRTOK 65 #define SSH_MSG_USERAUTH_GSSAPI_MIC 66
The numbers 60-79 are specific to user authentication and may be redefined by other user auth methods. Note that in the method described in this document, message number 62 is unused.
The numbers 60-79 are specific to user authentication and may be redefined by other user auth methods. Note that in the method described in this document, message number 62 is unused.
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Hutzelman, et al. Standards Track [Page 21] RFC 4462 SSH GSS-API Methods May 2006
7. GSS-API Considerations
7. GSS-API Considerations
7.1. Naming Conventions
7.1. Naming Conventions
In order to establish a GSS-API security context, the SSH client needs to determine the appropriate targ_name to use in identifying the server when calling GSS_Init_sec_context(). For this purpose, the GSS-API mechanism-independent name form for host-based services is used, as described in Section 4.1 of [GSSAPI].
In order to establish a GSS-API security context, the SSH client needs to determine the appropriate targ_name to use in identifying the server when calling GSS_Init_sec_context(). For this purpose, the GSS-API mechanism-independent name form for host-based services is used, as described in Section 4.1 of [GSSAPI].
In particular, the targ_name to pass to GSS_Init_sec_context() is obtained by calling GSS_Import_name() with an input_name_type of GSS_C_NT_HOSTBASED_SERVICE, and an input_name_string consisting of the string "host@" concatenated with the hostname of the SSH server.
In particular, the targ_name to pass to GSS_Init_sec_context() is obtained by calling GSS_Import_name() with an input_name_type of GSS_C_NT_HOSTBASED_SERVICE, and an input_name_string consisting of the string "host@" concatenated with the hostname of the SSH server.
Because the GSS-API mechanism uses the targ_name to authenticate the server's identity, it is important that it be determined in a secure fashion. One common way to do this is to construct the targ_name from the hostname as typed by the user; unfortunately, because some GSS-API mechanisms do not canonicalize hostnames, it is likely that this technique will fail if the user has not typed a fully-qualified, canonical hostname. Thus, implementers may wish to use other methods, but should take care to ensure they are secure. For example, one should not rely on an unprotected DNS record to map a host alias to the primary name of a server, or an IP address to a hostname, since an attacker can modify the mapping and impersonate the server.
Because the GSS-API mechanism uses the targ_name to authenticate the server's identity, it is important that it be determined in a secure fashion. One common way to do this is to construct the targ_name from the hostname as typed by the user; unfortunately, because some GSS-API mechanisms do not canonicalize hostnames, it is likely that this technique will fail if the user has not typed a fully-qualified, canonical hostname. Thus, implementers may wish to use other methods, but should take care to ensure they are secure. For example, one should not rely on an unprotected DNS record to map a host alias to the primary name of a server, or an IP address to a hostname, since an attacker can modify the mapping and impersonate the server.
Implementations of mechanisms conforming to this document MUST NOT use the results of insecure DNS queries to construct the targ_name. Clients MAY make use of a mapping provided by local configuration or use other secure means to determine the targ_name to be used. If a client system is unable to securely determine which targ_name to use, then it SHOULD NOT use this mechanism.
Implementations of mechanisms conforming to this document MUST NOT use the results of insecure DNS queries to construct the targ_name. Clients MAY make use of a mapping provided by local configuration or use other secure means to determine the targ_name to be used. If a client system is unable to securely determine which targ_name to use, then it SHOULD NOT use this mechanism.
7.2. Channel Bindings
7.2. Channel Bindings
This document recommends that channel bindings SHOULD NOT be specified in the calls during context establishment. This document does not specify any standard data to be used as channel bindings, and the use of network addresses as channel bindings may break SSH in environments where it is most useful.
This document recommends that channel bindings SHOULD NOT be specified in the calls during context establishment. This document does not specify any standard data to be used as channel bindings, and the use of network addresses as channel bindings may break SSH in environments where it is most useful.
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Hutzelman, et al. Standards Track [Page 22] RFC 4462 SSH GSS-API Methods May 2006
7.3. SPNEGO
7.3. SPNEGO
The use of the Simple and Protected GSS-API Negotiation Mechanism [SPNEGO] in conjunction with the authentication and key exchange methods described in this document is both unnecessary and undesirable. As a result, mechanisms conforming to this document MUST NOT use SPNEGO as the underlying GSS-API mechanism.
The use of the Simple and Protected GSS-API Negotiation Mechanism [SPNEGO] in conjunction with the authentication and key exchange methods described in this document is both unnecessary and undesirable. As a result, mechanisms conforming to this document MUST NOT use SPNEGO as the underlying GSS-API mechanism.
Since SSH performs its own negotiation of authentication and key exchange methods, the negotiation capability of SPNEGO alone does not provide any added benefit. In fact, as described below, it has the potential to result in the use of a weaker method than desired.
Since SSH performs its own negotiation of authentication and key exchange methods, the negotiation capability of SPNEGO alone does not provide any added benefit. In fact, as described below, it has the potential to result in the use of a weaker method than desired.
Normally, SPNEGO provides the added benefit of protecting the GSS-API mechanism negotiation. It does this by having the server compute a MIC of the list of mechanisms proposed by the client, and then checking that value at the client. In the case of key exchange, this protection is not needed because the key exchange methods described here already perform an equivalent operation; namely, they generate a MIC of the SSH exchange hash, which is a hash of several items including the lists of key exchange mechanisms supported by both sides. In the case of user authentication, the protection is not needed because the negotiation occurs over a secure channel, and the host's identity has already been proved to the user.
Normally, SPNEGO provides the added benefit of protecting the GSS-API mechanism negotiation. It does this by having the server compute a MIC of the list of mechanisms proposed by the client, and then checking that value at the client. In the case of key exchange, this protection is not needed because the key exchange methods described here already perform an equivalent operation; namely, they generate a MIC of the SSH exchange hash, which is a hash of several items including the lists of key exchange mechanisms supported by both sides. In the case of user authentication, the protection is not needed because the negotiation occurs over a secure channel, and the host's identity has already been proved to the user.
The use of SPNEGO combined with GSS-API mechanisms used without SPNEGO can lead to interoperability problems. For example, a client that supports key exchange using the Kerberos V5 GSS-API mechanism [KRB5-GSS] only underneath SPNEGO will not interoperate with a server that supports key exchange only using the Kerberos V5 GSS-API mechanism directly. As a result, allowing GSS-API mechanisms to be used both with and without SPNEGO is undesirable.
The use of SPNEGO combined with GSS-API mechanisms used without SPNEGO can lead to interoperability problems. For example, a client that supports key exchange using the Kerberos V5 GSS-API mechanism [KRB5-GSS] only underneath SPNEGO will not interoperate with a server that supports key exchange only using the Kerberos V5 GSS-API mechanism directly. As a result, allowing GSS-API mechanisms to be used both with and without SPNEGO is undesirable.
If a client's policy is to first prefer GSS-API-based key exchange method X, then non-GSS-API method Y, then GSS-API-based method Z, and if a server supports mechanisms Y and Z but not X, then an attempt to use SPNEGO to negotiate a GSS-API mechanism might result in the use of method Z when method Y would have been preferable. As a result, the use of SPNEGO could result in the subversion of the negotiation algorithm for key exchange methods as described in Section 7.1 of [SSH-TRANSPORT] and/or the negotiation algorithm for user authentication methods as described in [SSH-USERAUTH].
If a client's policy is to first prefer GSS-API-based key exchange method X, then non-GSS-API method Y, then GSS-API-based method Z, and if a server supports mechanisms Y and Z but not X, then an attempt to use SPNEGO to negotiate a GSS-API mechanism might result in the use of method Z when method Y would have been preferable. As a result, the use of SPNEGO could result in the subversion of the negotiation algorithm for key exchange methods as described in Section 7.1 of [SSH-TRANSPORT] and/or the negotiation algorithm for user authentication methods as described in [SSH-USERAUTH].
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Hutzelman, et al. Standards Track [Page 23] RFC 4462 SSH GSS-API Methods May 2006
8. IANA Considerations
8. IANA Considerations
Consistent with Section 8 of [SSH-ARCH] and Section 4.6 of [SSH-NUMBERS], this document makes the following registrations:
Consistent with Section 8 of [SSH-ARCH] and Section 4.6 of [SSH-NUMBERS], this document makes the following registrations:
The family of SSH key exchange method names beginning with "gss-
group1-sha1-" and not containing the at-sign ('@'), to name the
key exchange methods defined in Section 2.3.
The family of SSH key exchange method names beginning with "gss- group1-sha1-" and not containing the at-sign ('@'), to name the key exchange methods defined in Section 2.3.
The family of SSH key exchange method names beginning with "gss-
gex-sha1-" and not containing the at-sign ('@'), to name the key
exchange methods defined in Section 2.5.
The family of SSH key exchange method names beginning with "gss- gex-sha1-" and not containing the at-sign ('@'), to name the key exchange methods defined in Section 2.5.
All other SSH key exchange method names beginning with "gss-" and
not containing the at-sign ('@'), to be reserved for future key
exchange methods defined in conformance with this document, as
noted in Section 2.6.
All other SSH key exchange method names beginning with "gss-" and not containing the at-sign ('@'), to be reserved for future key exchange methods defined in conformance with this document, as noted in Section 2.6.
The SSH host public key algorithm name "null", to name the NULL
host key algorithm defined in Section 5.
The SSH host public key algorithm name "null", to name the NULL host key algorithm defined in Section 5.
The SSH user authentication method name "gssapi-with-mic", to name
the GSS-API user authentication method defined in Section 3.
The SSH user authentication method name "gssapi-with-mic", to name the GSS-API user authentication method defined in Section 3.
The SSH user authentication method name "gssapi-keyex", to name
the GSS-API user authentication method defined in Section 4.
The SSH user authentication method name "gssapi-keyex", to name the GSS-API user authentication method defined in Section 4.
The SSH user authentication method name "gssapi" is to be
reserved, in order to avoid conflicts with implementations
supporting an earlier version of this specification.
The SSH user authentication method name "gssapi" is to be reserved, in order to avoid conflicts with implementations supporting an earlier version of this specification.
The SSH user authentication method name "external-keyx" is to be
reserved, in order to avoid conflicts with implementations
supporting an earlier version of this specification.
The SSH user authentication method name "external-keyx" is to be reserved, in order to avoid conflicts with implementations supporting an earlier version of this specification.
This document creates no new registries.
This document creates no new registries.
9. Security Considerations
9. Security Considerations
This document describes authentication and key-exchange protocols. As such, security considerations are discussed throughout.
This document describes authentication and key-exchange protocols. As such, security considerations are discussed throughout.
This protocol depends on the SSH protocol itself, the GSS-API, any underlying GSS-API mechanisms that are used, and any protocols on which such mechanisms might depend. Each of these components plays a part in the security of the resulting connection, and each will have its own security considerations.
This protocol depends on the SSH protocol itself, the GSS-API, any underlying GSS-API mechanisms that are used, and any protocols on which such mechanisms might depend. Each of these components plays a part in the security of the resulting connection, and each will have its own security considerations.
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Hutzelman, et al. Standards Track [Page 24] RFC 4462 SSH GSS-API Methods May 2006
The key exchange method described in Section 2 depends on the underlying GSS-API mechanism to provide both mutual authentication and per-message integrity services. If either of these features is not supported by a particular GSS-API mechanism, or by a particular implementation of a GSS-API mechanism, then the key exchange is not secure and MUST fail.
The key exchange method described in Section 2 depends on the underlying GSS-API mechanism to provide both mutual authentication and per-message integrity services. If either of these features is not supported by a particular GSS-API mechanism, or by a particular implementation of a GSS-API mechanism, then the key exchange is not secure and MUST fail.
In order for the "external-keyx" user authentication method to be used, it MUST have access to user authentication information obtained as a side-effect of the key exchange. If this information is unavailable, the authentication MUST fail.
In order for the "external-keyx" user authentication method to be used, it MUST have access to user authentication information obtained as a side-effect of the key exchange. If this information is unavailable, the authentication MUST fail.
Revealing information about the reason for an authentication failure may be considered by some sites to be an unacceptable security risk for a production environment. However, having that information available can be invaluable for debugging purposes. Thus, it is RECOMMENDED that implementations provide a means for controlling, as a matter of policy, whether to send SSH_MSG_USERAUTH_GSSAPI_ERROR, SSH_MSG_USERAUTH_GSSAPI_ERRTOK, and SSH_MSG_KEXGSS_ERROR messages, and SSH_MSG_KEXGSS_CONTINUE messages containing a GSS-API error token.
Revealing information about the reason for an authentication failure may be considered by some sites to be an unacceptable security risk for a production environment. However, having that information available can be invaluable for debugging purposes. Thus, it is RECOMMENDED that implementations provide a means for controlling, as a matter of policy, whether to send SSH_MSG_USERAUTH_GSSAPI_ERROR, SSH_MSG_USERAUTH_GSSAPI_ERRTOK, and SSH_MSG_KEXGSS_ERROR messages, and SSH_MSG_KEXGSS_CONTINUE messages containing a GSS-API error token.
10. Acknowledgements
10. Acknowledgements
The authors would like to thank the following individuals for their invaluable assistance and contributions to this document:
The authors would like to thank the following individuals for their invaluable assistance and contributions to this document:
o Sam Hartman
o Sam Hartman
o Love Hornquist-Astrand
o Love Hornquist-Astrand
o Joel N. Weber II
o Joel N. Weber II
o Simon Wilkinson
o Simon Wilkinson
o Nicolas Williams
o Nicolas Williams
Much of the text describing DH group exchange was borrowed from [GROUP-EXCHANGE], by Markus Friedl, Niels Provos, and William A. Simpson.
Much of the text describing DH group exchange was borrowed from [GROUP-EXCHANGE], by Markus Friedl, Niels Provos, and William A. Simpson.
Hutzelman, et al. Standards Track [Page 25] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 25] RFC 4462 SSH GSS-API Methods May 2006
11. References
11. References
11.1. Normative References
11.1. Normative References
[ASN1] ISO/IEC, "ASN.1 Encoding Rules: Specification of
Basic Encoding Rules (BER), Canonical Encoding
Rules (CER) and Distinguished Encoding Rules
(DER)", ITU-T Recommendation X.690 (1997), ISO/
IEC 8825-1:1998, November 1998.
[ASN1] ISO/IEC, "ASN.1 Encoding Rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", ITU-T Recommendation X.690 (1997), ISO/ IEC 8825-1:1998, November 1998.
[GROUP-EXCHANGE] Friedl, M., Provos, N., and W. Simpson, "Diffie-
Hellman Group Exchange for the Secure Shell (SSH)
Transport Layer Protocol", RFC 4419, March 2006.
[GROUP-EXCHANGE] Friedl, M., Provos, N., and W. Simpson, "Diffie- Hellman Group Exchange for the Secure Shell (SSH) Transport Layer Protocol", RFC 4419, March 2006.
[GSSAPI] Linn, J., "Generic Security Service Application
Program Interface Version 2, Update 1", RFC 2743,
January 2000.
[GSSAPI] Linn, J., "Generic Security Service Application Program Interface Version 2, Update 1", RFC 2743, January 2000.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[LANGTAG] Alvestrand, H., "Tags for the Identification of
Languages", BCP 47, RFC 3066, January 2001.
[LANGTAG] Alvestrand, H., "Tags for the Identification of Languages", BCP 47, RFC 3066, January 2001.
[MD5] Rivest, R., "The MD5 Message-Digest Algorithm", RFC
1321, April 1992.
[MD5] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April 1992.
[MIME] Freed, N. and N. Borenstein, "Multipurpose Internet
Mail Extensions (MIME) Part One: Format of Internet
Message Bodies", RFC 2045, November 1996.
[MIME] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996.
[SSH-ARCH] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
Protocol Architecture", RFC 4251, January 2006.
[SSH-ARCH] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Protocol Architecture", RFC 4251, January 2006.
[SSH-CONNECT] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
Connection Protocol", RFC 4254, January 2006.
[SSH-CONNECT] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Connection Protocol", RFC 4254, January 2006.
[SSH-NUMBERS] Lehtinen, S. and C. Lonvick, "The Secure Shell
(SSH) Protocol Assigned Numbers", RFC 4250, January
2006.
[SSH-NUMBERS] Lehtinen, S. and C. Lonvick, "The Secure Shell (SSH) Protocol Assigned Numbers", RFC 4250, January 2006.
[SSH-TRANSPORT] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
Transport Layer Protocol", RFC 4253, January 2006.
[SSH-TRANSPORT] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Transport Layer Protocol", RFC 4253, January 2006.
[SSH-USERAUTH] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, January 2006.
[SSH-USERAUTH] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Authentication Protocol", RFC 4252, January 2006.
Hutzelman, et al. Standards Track [Page 26] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 26] RFC 4462 SSH GSS-API Methods May 2006
[UTF8] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[UTF8] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003.
11.2. Informative References
11.2. Informative References
[KRB5] Neuman, C., Yu, T., Hartman, S., and K. Raeburn,
"The Kerberos Network Authentication Service (V5)",
RFC 4120, July 2005.
[KRB5] Neuman, C., Yu, T., Hartman, S., and K. Raeburn, "The Kerberos Network Authentication Service (V5)", RFC 4120, July 2005.
[KRB5-GSS] Zhu, L., Jaganathan, K., and S. Hartman, "The
Kerberos Version 5 Generic Security Service
Application Program Interface (GSS-API) Mechanism:
Version 2", RFC 4121, July 2005.
[KRB5-GSS] Zhu, L., Jaganathan, K., and S. Hartman, "The Kerberos Version 5 Generic Security Service Application Program Interface (GSS-API) Mechanism: Version 2", RFC 4121, July 2005.
[SASLPREP] Zeilenga, K., "SASLprep: Stringprep Profile for
User Names and Passwords", RFC 4013, February 2005.
[SASLPREP] Zeilenga, K., "SASLprep: Stringprep Profile for User Names and Passwords", RFC 4013, February 2005.
[SPNEGO] Zhu, L., Leach, P., Jaganathan, K., and W.
Ingersoll, "The Simple and Protected Generic
Security Service Application Program Interface
(GSS-API) Negotiation Mechanism", RFC 4178, October
2005.
[SPNEGO] Zhu, L., Leach, P., Jaganathan, K., and W. Ingersoll, "The Simple and Protected Generic Security Service Application Program Interface (GSS-API) Negotiation Mechanism", RFC 4178, October 2005.
Hutzelman, et al. Standards Track [Page 27] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 27] RFC 4462 SSH GSS-API Methods May 2006
Authors' Addresses
Authors' Addresses
Jeffrey Hutzelman Carnegie Mellon University 5000 Forbes Ave Pittsburgh, PA 15213 US
Jeffrey Hutzelman Carnegie Mellon University 5000 Forbes Ave Pittsburgh, PA 15213 US
Phone: +1 412 268 7225 EMail: jhutz+@cmu.edu URI: http://www.cs.cmu.edu/~jhutz/
Phone: +1 412 268 7225 EMail: jhutz+@cmu.edu URI: http://www.cs.cmu.edu/~jhutz/
Joseph Salowey Cisco Systems 2901 Third Avenue Seattle, WA 98121 US
Joseph Salowey Cisco Systems 2901 Third Avenue Seattle, WA 98121 US
Phone: +1 206 256 3380 EMail: jsalowey@cisco.com
Phone: +1 206 256 3380 EMail: jsalowey@cisco.com
Joseph Galbraith Van Dyke Technologies, Inc. 4848 Tramway Ridge Dr. NE Suite 101 Albuquerque, NM 87111 US
Joseph Galbraith Van Dyke Technologies, Inc. 4848 Tramway Ridge Dr. NE Suite 101 Albuquerque, NM 87111 US
EMail: galb@vandyke.com
EMail: galb@vandyke.com
Von Welch University of Chicago & Argonne National Laboratory Distributed Systems Laboratory 701 E. Washington Urbana, IL 61801 US
Von Welch University of Chicago & Argonne National Laboratory Distributed Systems Laboratory 701 E. Washington Urbana, IL 61801 US
EMail: welch@mcs.anl.gov
EMail: welch@mcs.anl.gov
Hutzelman, et al. Standards Track [Page 28] RFC 4462 SSH GSS-API Methods May 2006
Hutzelman, et al. Standards Track [Page 28] RFC 4462 SSH GSS-API Methods May 2006
Full Copyright Statement
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Copyright (C) The Internet Society (2006).
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Hutzelman, et al. Standards Track [Page 29]
Hutzelman, et al. Standards Track [Page 29]
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