draft-ietf-nfsv4-rpcsec-gssv3-06.txt   draft-ietf-nfsv4-rpcsec-gssv3-07.txt 
NFSv4 W. Adamson NFSv4 W. Adamson
Internet-Draft NetApp Internet-Draft NetApp
Intended status: Standards Track N. Williams Intended status: Standards Track N. Williams
Expires: April 20, 2014 Cryptonector Expires: August 7, 2014 Cryptonector
October 17, 2013 February 03, 2014
Remote Procedure Call (RPC) Security Version 3 Remote Procedure Call (RPC) Security Version 3
draft-ietf-nfsv4-rpcsec-gssv3-06.txt draft-ietf-nfsv4-rpcsec-gssv3-07.txt
Abstract Abstract
This document specifies version 3 of the Remote Procedure Call (RPC) This document specifies version 3 of the Remote Procedure Call (RPC)
security protocol (RPCSEC_GSS). This protocol provides for compound security protocol (RPCSEC_GSS). This protocol provides for compound
authentication of client hosts and users to server (constructed by authentication of client hosts and users to server (constructed by
generic composition), security label assertions for multi-level and generic composition), security label assertions for multi-level and
type enforcement, structured privilege assertions, and channel type enforcement, structured privilege assertions, and channel
bindings. bindings.
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This Internet-Draft will expire on April 20, 2014. This Internet-Draft will expire on August 7, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction and Motivation . . . . . . . . . . . . . . . . . 3
1.1. Applications of RPCSEC_GSSv3 . . . . . . . . . . . . . . . 4 2. The RPCSEC_GSSv3 Protocol . . . . . . . . . . . . . . . . . . 4
2. The RPCSEC_GSSv3 Protocol . . . . . . . . . . . . . . . . . . 5 2.1. Compatibility with RPCSEC_GSSv2 . . . . . . . . . . . . . 5
2.1. New auth_stat Values . . . . . . . . . . . . . . . . . . . 9 2.2. New REPLY verifier . . . . . . . . . . . . . . . . . . . . 5
2.2. RPC Message Credential and Verifier . . . . . . . . . . . 10 2.3. New Version Number . . . . . . . . . . . . . . . . . . . . 5
2.3. Control Messages . . . . . . . . . . . . . . . . . . . . . 10 2.4. New Control Procedures . . . . . . . . . . . . . . . . . . 7
2.3.1. Create Request . . . . . . . . . . . . . . . . . . . . 11 2.4.1. New Control Procedure - RPCSEC_GSS_CREATE . . . . . . 8
2.3.2. Destruction Request . . . . . . . . . . . . . . . . . 15 2.4.2. New Control Procedure - RPCSEC_GSS_LIST . . . . . . . 14
2.3.3. List Request . . . . . . . . . . . . . . . . . . . . . 15 2.5. Extensibility . . . . . . . . . . . . . . . . . . . . . . 15
2.3.4. Extensibility . . . . . . . . . . . . . . . . . . . . 16 2.6. New auth_stat Values . . . . . . . . . . . . . . . . . . . 15
2.4. Data Messages . . . . . . . . . . . . . . . . . . . . . . 16 3. Version Negotiation . . . . . . . . . . . . . . . . . . . . . 16
3. Security Considerations . . . . . . . . . . . . . . . . . . . 17 4. Operational Recommendation for Deployment . . . . . . . . . . 16
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 5. Security Considerations . . . . . . . . . . . . . . . . . . . 16
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
5.1. Normative References . . . . . . . . . . . . . . . . . . . 18 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2. Informative References . . . . . . . . . . . . . . . . . . 19 7.1. Normative References . . . . . . . . . . . . . . . . . . . 17
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 19 7.2. Informative References . . . . . . . . . . . . . . . . . . 18
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 18
Appendix B. RFC Editor Notes . . . . . . . . . . . . . . . . . . 19 Appendix B. RFC Editor Notes . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction and Motivation
The original RPCSEC_GSS protocol [2] provided for authentication of The original RPCSEC_GSS protocol [2] provided for authentication of
RPC clients and servers to each other using the Generic Security RPC clients and servers to each other using the Generic Security
Services Application Programming Interface (GSS-API) [3]. The second Services Application Programming Interface (GSS-API) [3]. The second
version of RPCSEC_GSS [4] added support for channel bindings [5]. version of RPCSEC_GSS [4] added support for channel bindings [5].
We find that GSS-API mechanisms are insufficient for communicating We find that GSS-API mechanisms are insufficient for communicating
certain aspects of a client's authority to a server. The GSS-API and certain aspects of authority to a server. The GSS-API and its
its mechanisms certainly could be extended to address this mechanisms certainly could be extended to address this shortcoming,
shortcoming, but it seems be far simpler to address it at the but it seems be far simpler to address it at the application layer,
application layer, namely, in this case, RPCSEC_GSS. namely, in this case, RPCSEC_GSS.
The motivation for RPCSEC_GSSv3 is to add support for labeled The motivation for RPCSEC_GSSv3 is to add support for labeled
security and server-side copy for NFSv4 (see [6] and [9]). Both of security and server-side copy for NFSv4.
these features require assertions of authority from the client.
Assertions need to be verified. One party that can verify an Labeled NFS (see Section 8 of [6]) uses the subject label provided by
assertion is the client host, which can authenticate to the server the client via the RPCSEC_GSSv3 layer to enforce MAC access to
using its own credentials. We can also require users to verify an objects owned by the server to enable server guest mode or full mode
assertion as well. This calls for compound authentication. labeled NFS.
Because the design of RPCSEC_GSSv3 relies on either RPCSEC_GSS A traditional inter-server file copy entails the user gaining access
version 1 (though version 2 can be used) to do the actual GSS-API to a file on the source, reading it, and writing it to a file on the
security context establishment, we add support for channel binding so destination. In secure NFSv4 inter-server server-side copy (see
that implementors who have implemented RPCSEC_GSS version 1 but not Section 3.4.1 of [6]), the user first secures access to both source
version 2 can provide a (simplified) channel binding implementation and destination files, and then uses RPCSEC_GSSv3 compound
using RPCSEC_GSSv3. authentication and structured privileges to authorize the destination
to copy the file from the source on behalf of the user.
We therefore describe a new version of RPCSEC_GSS that allows for the We therefore describe RPCSEC_GSS version 3 (RPCSEC_GSSv3).
following client-side assertions of authority: RPCSEC_GSSv3 is the same as RPCSEC_GSSv2 [4], except that the
following assertions of authority have been added.
o Security labels for multi-level, type enforcement, and other o Security labels for multi-level, type enforcement, and other
labeled security models. See [10], [11], [12], [6] and [9]. labeled security models. See [9], [10], [11], [6] and [12].
o Application-specific structured privileges. For an example see o Application-specific structured privileges. For an example see
server-side copy [6]. server-side copy [6].
o Compound authentication of the client host and user to the server o Compound authentication of the client host and user to the server
done by binding two RPCSEC_GSS handles. done by binding two RPCSEC_GSS handles. For an example see
server-side copy [6].
o Simplified channel binding. o Simplified channel binding.
Assertions of labels and privileges are evaluated by the server, Assertions of labels and privileges are evaluated by the server,
which may then map the asserted values to other values, all according which may then map the asserted values to other values, all according
to server-side policy. to server-side policy.
We add an option for enumerating server supported label format We add an option for enumerating server supported label format
specifiers (LFS). The LFS and Label Format Registry are described in specifiers (LFS). The LFS and Label Format Registry are described in
detail in [13]. detail in [13].
RPCSEC_GSSv3 is patterned as follows: This document contains the External Data Representation (XDR) ([7])
definitions for the RPCSEC_GSSv3 protocol. The XDR description is
o A client uses an existing RPCSEC_GSSv1 (or RPCSEC_GSSv2) context provided in this document in a way that makes it simple for the
handle to protect RPCSEC_GSSv3 exchanges (this will be termed the reader to extract into ready to compile form. The reader can feed
"parent" handle) this document in the following shell script to produce the machine
readable XDR description of RPCSEC_GSSv3:
o The server issues a "child" RPCSEC_GSSv3 handle which uses the <CODE BEGINS>
underlying GSS-API security context of the parent handle in all
subsequent exchanges that uses the child handle.
o The child handle, however, has its own sequence number space #!/bin/sh
distinct from that of the parent. grep "^ *///" | sed 's?^ */// ??' | sed 's?^ *///$??'
[[Comment.1: I removed the "child has a window distinct from that of <CODE ENDS>
the parent" because RFC2203 states: " In a successful response, the
seq_window field is set to the sequence window length supported by
the server for this context. This window specifies the maximum
number of client requests that may be outstanding for this context."
If we want a distinct window, we will need to add that to the
rpc_gss3_create_res so that the server can set it. I see no point -
just use the parent window. --AA]]
[[Comment.2: RFC2203 states that when data integrity is used, the I.e. if the above script is stored in a file called "extract.sh", and
seq_num in the rpc_gss_data_t must be the same as in the credential. this document is in a file called "spec.txt", then the reader can do:
This means that using data integrity with GSS3 context's can not
simply construct it using the parent context as the seq_num must be
from the GSS3 context. --AA]]
This means that RPCSEC_GSSv3 depends on an existing parent <CODE BEGINS>
RPCSEC_GSSv1 or RPCSEC_GSSv2 context for actual GSS-API security
context establishment. This keeps the specification of RPCSEC_GSSv3
simple by avoiding the need to duplicate the core functionality of
RPCSEC_GSS version 1. This also means that an RPCSEC_GSSv3 context
MUST be destroyed prior to it's parent context being destroyed.
[[Comment.3: Destruction of the parent context => first destroy child sh extract.sh < spec.txt > rpcsec_gss_v3.x
handle. IOW fail the RPCSEC_GSS_DESTROY of parent with new
RPCSEC_GSS3_CONTEXT_EXISTS error code OR upon the destruction of the
parent context destroy any associated RPCSEC_GSSv3 contexts OR.....
--AA]]
1.1. Applications of RPCSEC_GSSv3 <CODE ENDS>
The common uses of RPCSEC_GSSv3, particularly for NFSv4 [6], are The effect of the script is to remove leading white space from each
expected to be: line, plus a sentinel sequence of "///".
a. labeled security: client-side process label assertion [+ 2. The RPCSEC_GSSv3 Protocol
privilege assertion] + compound client host & user
authentication;
b. inter-server server-side copy: compound client host & user RPCSEC_GSSv3 is the same as RPCSEC_GSSv2 [4], except that support for
authentication [+ critical structured privilege assertions] assertions has been added. The entire RPCSEC_GSSv3 protocol is not
presented. Instead the differences between RPCSEC_GSSv3 and
RPCSEC_GSSv2 are shown.
Labeled NFS (see Section 8 of [6]) uses the subject label provided by RPCSEC_GSSv3 is patterned as follows:
the client via the RPCSEC_GSSv3 layer to enforce MAC access to
objects owned by the server to enable server guest mode or full mode
labeled NFS.
[[Comment.4: check that this language states what NFSv4.2 labeled NFS o A client uses an existing RPCSEC_GSSv3 context handle to protect
problem we are really solving. (setting labels on the server) --AA]] RPCSEC_GSSv3 exchanges, this will be termed the "parent" handle.
[[Comment.1: CAN A CHILD handle be used as a parent? --AA]]
A traditional inter-server file copy entails the user gaining access o The server issues a "child" RPCSEC_GSSv3 handle in the
to a file on the source, reading it, and writing it to a file on the RPCSEC_GSS_CREATE response which uses the underlying GSS-API
destination. In secure NFSv4 inter-server server-side copy (see security context of the parent handle in all subsequent exchanges
Section 3.4.1 of [6]), the user first secures access to both source that uses the child handle.
and destination files, and then uses RPCSEC_GSSv3 compound
authentication and structured privileges to authorize the destination
to copy the file from the source on behalf of the user.
2. The RPCSEC_GSSv3 Protocol 2.1. Compatibility with RPCSEC_GSSv2
This document contains the External Data Representation (XDR) ([7]) The functionality of RPCSEC_GSSv2 [4] is fully supported by
definitions for the RPCSEC_GSSv3 protocol. RPCSEC_GSSv3.
The XDR description is provided in this document in a way that makes 2.2. New REPLY verifier
it simple for the reader to extract into ready to compile form. The
reader can feed this document in the following shell script to
produce the machine readable XDR description of RPCSEC_GSSv3:
#!/bin/sh The RPCSEC_GSSv3 child handle uses the same GSS context as the parent
grep "^ *///" | sed 's?^ */// ??' | sed 's?^ *///$??' handle. Since a child and parent RPCSEC_GSSv3 handle could have the
same RPCSEC_GSS sequence numbers, and the verifier of RPCSEC_GSS
replies computes a MIC on just the sequence number, this provides
opportunities for man in the middle attacks.
I.e. if the above script is stored in a file called "extract.sh", and This is easily addressed: RPCSEC_GSS version 3 MUST change the
this document is in a file called "spec.txt", then the reader can do: verifier of the reply to compute the verifier using the exact same
input as that is used for verifier of the request, except for the
mtype change from CALL to REPLY:
sh extract.sh < spec.txt > rpcsec_gss_v3.x unsigned int xid;
msg_type mtype; /* set to REPLY */
unsigned int rpcvers;
unsigned int prog;
unsigned int vers;
unsigned int proc;
opaque_auth cred; /* captures the RPCSEC_GSS handle */
The effect of the script is to remove leading white space from each 2.3. New Version Number
line, plus a sentinel sequence of "///".
The XDR description, with the sentinel sequence follows: <CODE BEGINS>
/// /* /// /*
/// * Copyright (c) 2013 IETF Trust and the persons /// * Copyright (c) 2013 IETF Trust and the persons
/// * identified as the document authors. All rights /// * identified as the document authors. All rights
/// * reserved. /// * reserved.
/// * /// *
/// * The document authors are identified in [RFC2203], /// * The document authors are identified in [RFC2203],
/// * [RFC5403], and [RFCxxxx]. /// * [RFC5403], and [RFCxxxx].
/// * /// *
/// * Redistribution and use in source and binary forms, /// * Redistribution and use in source and binary forms,
skipping to change at page 7, line 4 skipping to change at page 6, line 35
/// * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING /// * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
/// * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF /// * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
/// * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. /// * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
/// */ /// */
/// ///
/// /* /// /*
/// * This code was derived from [RFC2203]. Please /// * This code was derived from [RFC2203]. Please
/// * reproduce this note if possible. /// * reproduce this note if possible.
/// */ /// */
/// ///
/// /*
/// * rpcsec_gss_v3.x
/// */
///
/// enum rpc_gss_service_t { /// enum rpc_gss_service_t {
/// /* Note: the enumerated value for 0 is reserved. */ /// /* Note: the enumerated value for 0 is reserved. */
/// rpc_gss_svc_none = 1, /// rpc_gss_svc_none = 1,
/// rpc_gss_svc_integrity = 2, /// rpc_gss_svc_integrity = 2,
/// rpc_gss_svc_privacy = 3, /// rpc_gss_svc_privacy = 3,
/// rpc_gss_svc_channel_prot = 4 /// rpc_gss_svc_channel_prot = 4
/// }; /// };
/// ///
/// enum rpc_gss_proc_t { /// enum rpc_gss_proc_t {
/// RPCSEC_GSS_DATA = 0, /// RPCSEC_GSS_DATA = 0,
/// RPCSEC_GSS_INIT = 1, /// RPCSEC_GSS_INIT = 1,
/// RPCSEC_GSS_CONTINUE_INIT = 2, /// RPCSEC_GSS_CONTINUE_INIT = 2,
/// RPCSEC_GSS_DESTROY = 3, /// RPCSEC_GSS_DESTROY = 3,
/// RPCSEC_GSS_BIND_CHANNEL = 4 /// RPCSEC_GSS_BIND_CHANNEL = 4, /* not used */
/// RPCSEC_GSS_CREATE = 5, /* new */
/// RPCSEC_GSS_LIST = 6 /* new */
/// }; /// };
/// ///
/// struct rpc_gss_cred_vers_1_t { /// struct rpc_gss_cred_vers_1_t {
/// rpc_gss_proc_t gss_proc; /* control procedure */ /// rpc_gss_proc_t gss_proc; /* control procedure */
/// unsigned int seq_num; /* sequence number */ /// unsigned int seq_num; /* sequence number */
/// rpc_gss_service_t service; /* service used */ /// rpc_gss_service_t service; /* service used */
/// opaque handle<>; /* context handle */ /// opaque handle<>; /* context handle */
/// }; /// };
/// ///
/// enum rpc_gss3_proc_t {
/// RPCSEC_GSS3_DATA = 0,
/// RPCSEC_GSS3_LIST = 5,
/// RPCSEC_GSS3_CREATE = 6,
/// RPCSEC_GSS3_DESTROY = 7
/// };
///
/// struct rpc_gss_cred_vers_3_t {
/// rpc_gss3_proc_t gss_proc;
/// unsigned int seq_num;
/// rpc_gss_service_t service;
/// opaque handle<>;
/// };
///
/// const RPCSEC_GSS_VERS_1 = 1; /// const RPCSEC_GSS_VERS_1 = 1;
/// const RPCSEC_GSS_VERS_2 = 2; /// const RPCSEC_GSS_VERS_2 = 2;
/// const RPCSEC_GSS_VERS_3 = 3; /* new */ /// const RPCSEC_GSS_VERS_3 = 3; /* new */
/// ///
/// union rpc_gss_cred_t switch (unsigned int rgc_version) { /// union rpc_gss_cred_t switch (unsigned int rgc_version) {
/// case RPCSEC_GSS_VERS_1: /// case RPCSEC_GSS_VERS_1:
/// case RPCSEC_GSS_VERS_2: /// case RPCSEC_GSS_VERS_2:
/// rpc_gss_cred_vers_1_t rgc_cred_v1;
/// case RPCSEC_GSS_VERS_3: /* new */ /// case RPCSEC_GSS_VERS_3: /* new */
/// rpc_gss_cred_vers_3_t rgc_cred_v3; /// rpc_gss_cred_vers_1_t rgc_cred_v1;
/// };
///
/// const MAXSEQ = 0x80000000;
///
/// struct rpc_gss3_gss_binding {
/// unsigned int vers;
/// opaque handle<>;
/// opaque nonce<>;
/// opaque mic<>;
/// };
///
/// typedef opaque rpc_gss3_chan_binding<>;
///
/// struct rpc_gss3_lfs {
/// unsigned int lfs_id;
/// unsigned int pi_id;
/// };
///
/// struct rpc_gss3_label {
/// rpc_gss3_lfs lfs;
/// opaque label<>;
/// };
///
/// struct rpc_gss3_privs {
/// string name; /* human readable */
/// opaque privilege<>;
/// };
///
/// enum rpc_gss3_assertion_type {
/// LABEL = 0,
/// PRIVS = 1
/// };
///
/// union rpc_gss3_assertion_u
/// switch (rpc_gss3_assertion_type atype) {
/// case LABEL:
/// rpc_gss3_label label;
/// case PRIVS:
/// rpc_gss3_privs privs;
/// default:
/// opaque ext<>;
/// };
///
/// struct rpc_gss3_assertion {
/// bool critical;
/// rpc_gss3_assertion_u assertion;
/// };
///
/// struct rpc_gss3_create_args {
/// rpc_gss3_gss_binding *compound_binding;
/// rpc_gss3_chan_binding *chan_binding_mic;
/// rpc_gss3_assertion assertions<>;
/// };
///
/// struct rpc_gss3_create_res {
/// opaque handle<>;
/// rpc_gss3_chan_binding *chan_binding_mic;
/// rpc_gss3_assertion granted_assertions<>;
/// };
///
/// enum rpc_gss3_list_item {
/// LABEL = 0,
/// };
///
/// struct rpc_gss3_list_args {
/// rpc_gss3_list_item list_what<>;
/// };
///
/// union rpc_gss3_list_item_u
/// switch (rpc_gss3_list_item itype) {
/// case LABEL:
/// rpc_gss3_lable labels<>;
/// default:
/// opaque ext<>;
/// }; /// };
/// ///
/// typedef rpc_gss3_list_item_u rpc_gss3_list_res<>;
2.1. New auth_stat Values
RPCSEC_GSSv3 requires the addition of several values to the auth_stat
enumerated type definition:
enum auth_stat {
...
/*
* RPCSEC_GSSv3 errors
*/
RPCSEC_GSS3_COMPOUND_PROBEM = <>,
RPCSEC_GSS3_LABEL_PROBLEM = <>,
RPCSEC_GSS3_UNKNOWN_PRIVILEGE = <>
RPCSEC_GSS3_UNKNOWN_MESSAGE = <>
};
[[Comment.5: fix above into YYY. All the entries are TBD... --NW]]
[[Comment.6: The compound authentication problems are: can't find the
handle plus handle version on the target, or the MIC of the nounce
does not match. Both of these errors already have auth_stat entries:
RPCSEC_GSS_CREDPROBLEM for the first and "reply status of
MSG_ACCEPTED, and an acceptance status of GARBAGE_ARGS." --AA]]
2.2. RPC Message Credential and Verifier
The rpc_gss_cred_vers_3_t type is used in much the same way that
rpc_gss_cred_vers_1_t is used in RPCSEC_GSSv1, that is: as the arm of
the rpc_gss_cred_t discriminated union in the RPC message header
opaque_auth structure corresponding to version 3 (RPCSEC_GSS_VERS_3).
It differs from rpc_gss_cred_vers_1_t in that:
a. the values for gss_proc corresponding to control messages are <CODE ENDS>
different.
b. the handle field is the RPCSEC_GSSv3 (child) handle, except for As seen above, the RPCSEC_GSSv3 credential has the same format as the
the RPCSEC_GSS3_CREATE and RPCSEC_GSS3_LIST control messages RPCSEC_GSSv1 [2] and RPCSEC_GSSv2 [4] credential. Setting the
where it is set to the parent context handle. rgc_version field to 3 indicates that the initiator and target
support the new RPCSEC_GSSv3 control procedures.
For all RPCSEC_GSSv3 data and control messages, the verifier field in 2.4. New Control Procedures
the RPC message header is constructed in the RPCSEC_GSSv1 manner
using the parent GSS-API security context.
2.3. Control Messages There are two new RPCSEC_GSSv3 control procedures: RPCSEC_GSS_CREATE,
RPCSEC_GSS_LIST.
There are three RPCSEC_GSSv3 control messages: RPCSEC_GSS3_CREATE, The RPCSEC_GSS_CREATE procedure binds any combination of assertions:
RPCSEC_GSS3_DESTROY, and RPCSEC_GSS3_LIST. compound authentication, labels, structured privileges, or channel
bindings to a new RPCSEC_GSSv3 context returned in the
rgss3_create_res rcr_handle field.
RPCSEC_GSSv3 control messages are similar to the RPCSEC_GSSv1 The RPCSEC_GSS_LIST procedure queries the target for supported
RPCSEC_GSS_DESTROY control message (see section 5.4 [2]) in that the assertions.
sequence number in the request must be valid, and the header checksum
in the verifier must be valid. In other words, they look a lot like
an RPCSEC_GSSv3 data message with the header procedure set to
NULLPROC.
As in RPCSEC_GSSv1, the RPCSEC_GSSv3 control messages may contain RPCSEC_GSS version 3 control messages are similar to the RPCSEC_GSS
information following the verifier in the body of the NULLPROC version 1 and version2 RPCSEC_GSS_DESTROY control message (see
procedure. section 5.4 [2]) in that the sequence number in the request must be
valid, and the header checksum in the verifier must be valid. As in
RPCSEC_GSS version 1 and version 2, the RPCSEC_GSSv version 3 control
messages may contain call data following the verifier in the body of
the NULLPROC procedure. In other words, they look a lot like an
RPCSEC_GSS data message with the header procedure set to NULLPROC.
The client MUST use one of the following security services to protect The client MUST use one of the following security services to protect
any RPCSEC_GSSv3 control message: the RPCSEC_GSS_CREATE or RPCSEC_GSS_LIST control message:
o rpc_gss_svc_channel_prot (see RPCSEC_GSSv2 [4])
o rpc_gss_svc_channel_prot (see RPCSEC_GSSv2)
o rpc_gss_svc_integrity o rpc_gss_svc_integrity
o rpc_gss_svc_privacy o rpc_gss_svc_privacy
Specifically the client MUST NOT use rpc_gss_svc_none. Specifically the client MUST NOT use rpc_gss_svc_none.
For RPCSEC_GSSv3 control messages the rpc_gss_cred_vers_3_t in the 2.4.1. New Control Procedure - RPCSEC_GSS_CREATE
RPC message opaque_auth structure is encoded as follows:
o the union rpc_gss_cred_t version is set to 3 with the value being
of type rpc_gss_cred_vers_3_t instead of rpc_gss_cred_vers_1_t.
o the gss_proc is set to one of RPCSEC_GSS3_CREATE,
RPCSEC_GSS3_DESTROY, or RPCSEC_GSS3_LIST.
o the seq_num is a valid sequence number for the context in the
handle field.
o the rpc_gss_service_t is one of rpc_gss_svc_integrity,
rpc_gss_svc_privacy, or rpc_gss_svc_channel_prot.
o the rpc_gss_cred_vers_3_t handle field is either set to the parent <CODE BEGINS>
context handle for RPCSEC_GSS3_CREATE and RPCSEC_GSS3_LIST, or to
the GSS3 child handle for RPCSEC_GSS3_DESTROY.
2.3.1. Create Request /// struct rgss3_create_args {
/// rgss3_gss_binding *rca_comp_auth;
/// rgss3_chan_binding *rca_chan_bind_mic;
/// rgss3_assertion rca_assertions<>;
/// };
///
/// struct rgss3_create_res {
/// opaque rcr_handle<>;
/// rgss3_gss_binding *rcr_comp_auth;
/// rgss3_chan_binding *rcr_chan_bind_mic;
/// rgss3_assertion rcr_assertions<>;
/// };
///
/// enum rgss3_assertion_type {
/// LABEL = 0,
/// PRIVS = 1
/// };
///
/// union rgss3_assertion_u
/// switch (rgss3_assertion_type atype) {
/// case LABEL:
/// rgss3_label rau_label;
/// case PRIVS:
/// rgss3_privs rau_privs;
/// default:
/// opaque rau_ext<>;
/// };
///
/// struct rgss3_assertion {
/// bool ra_critical;
/// rgss3_assertion_u ra_assertion;
/// };
///
As noted in the introduction, RPCSEC_GSSv3 relies on the RPCSEC_GSS <CODE ENDS>
version 1 parent context (though version 2 can be used) secure
connection to do the actual GSS-API GSS3 security context
establishment. As such, for the RPCSEC_GSS3_CREATE request, the
rpc_gss_cred_vers_3_t fields in the RPC Call opaque_auth use the
parent context handle and seq_num stream.
The RPCSEC_GSS3_CREATE call message binds one or more items of The call data for an RPCSEC_GSS_CREATE request consists of an
several kinds into a new RPCSEC_GSSv3 context handle: rgss3_create_args which binds one or more items of several kinds to
the returned rcr_handle RPCSEC_GSSv3 context handle called the
"child" handle:
o another RPCSEC_GSS (version 1, 2, or 3) context handle (compound o Compound authentication: another RPCSEC_GSS context handle
authentication)
o a channel binding o Authorization assertions: labels and or privileges
o authorization assertions (labels, privileges) o A channel binding
The reply to this message consists of either an error or an The reply to this message consists of either an error or an
rpc_gss3_create_res structure which includes a new RPCSEC_GSSv3 rgss3_create_res structure.
handle, termed the "child" which is used for subsequent control and
data messages.
Upon successful RPCSEC_GSS3_CREATE, both the client and the server Upon successful RPCSEC_GSS_CREATE, both the client and the server
should associate the resultant GSSv3 child context handle with the SHOULD associate the resultant child rcr_handle context handle with
parent context handle in their GSS context caches so as to be able to the parent context handle in their GSS context caches so as to be
reference the parent context given the child context handle. able to reference the parent context given the child context handle.
RPCSEC_GSSv3 child handles MUST be destroyed upon the destruction of
the associated parent handle.
Server implementation and policy MAY result in labels, privileges, Server implementation and policy MAY result in labels, privileges,
and identities being mapped to concepts and values that are local to and identities being mapped to concepts and values that are local to
the server. Server policies should take into account the identity of the server. Server policies should take into account the identity of
the client and/or user as authenticated via the GSS-API. the client and/or user as authenticated via the GSS-API.
2.3.1.1. Compound Authentication 2.4.1.1. Compound Authentication
RPCSEC_GSSv3 allows for compound authentication of client hosts and <CODE BEGINS>
users to servers. As in non-compound authentication, there is a
parent handle used to protect the RPCSEC_GSS3_CREATE call message and ///
a resultant RPCSEC_GSSv3 child handle. In addition to the parent /// struct rgss3_gss_binding {
handle, the compound authentication create control message has a /// opaque rgb_handle<>; /* inner handle */
handle referenced via the compound_binding field of the /// opaque rgb_nonce<>;
RPCSEC_GSS3_CREATE arguments structure (rpc_gss3_create_args) termed /// opaque rgb_nounc_mic<>;
the "inner" handle, as well as a nonce and a MIC of that nounce /// };
created using the GSS-API security context associated with the ///
"inner" handle.
<CODE ENDS>
RPCSEC_GSSv3 clients MAY assert a compound authentication of the
client host and a user. This is done by including an assertion of
type rgss3_gss_binding in the RPCSEC_GSS_CREATE rgss3_create_args
call data. In addition to the parent handle (Section 2), the
compound authentication rgss3_gss_binding call data has an RPCSEC_GSS
version 3 handle referenced via the rgb_handle field termed the
"inner" handle. A nonce and a MIC of that nounce created using the
GSS-API security context associated with the inner handle is also
provided.
The target verifies the compounding by verifying the rgb_nouce_mic.
On a successful reply, the rgss3_gss_binding field in the
rgss3_create_res reply uses the parent RPCSEC_GSSv3 context as the
rgb_handle, the same rgb_nounce as was sent in the call data with the
rgb_nounce_mic created using the GSS-API security context associate
with the parent handle. Verification of the rbg_nounce_mic by the
initiator demonstrates that the target agrees to the compounding. On
failure, the rgss3_gss_binding field is not sent. (rgss3_gss_binding
is an optional field)
This feature is needed, for example, when a client wishes to use This feature is needed, for example, when a client wishes to use
authority assertions that the server may only grant if a user and a authority assertions that the server may only grant if a user and a
client are authenticated together to the server. Thus a server may client are authenticated together to the server. Thus a server may
refuse to grant requested authority to a user acting alone (e.g., via refuse to grant requested authority to a user acting alone (e.g., via
an unprivileged user-space program), or to a client acting alone an unprivileged user-space program), or to a client acting alone
(e.g. when a client is acting on behalf of a user) but may grant (e.g. when a client is acting on behalf of a user) but may grant
requested authority to a client acting on behalf of a user if the requested authority to a client acting on behalf of a user if the
server identifies the user and trusts the client. server identifies the user and trusts the client.
It is assumed that an unprivileged user-space program would not have It is assumed that an unprivileged user-space program would not have
access to client host credentials needed to establish a GSS-API access to client host credentials needed to establish a GSS-API
security context authenticating the client to the server, therefore security context authenticating the client to the server, therefore
an unprivileged user-space program could not create an RPCSEC_GSSv3 an unprivileged user-space program could not create an RPCSEC_GSSv3
RPCSEC_GSS3_CREATE message that successfully binds a client and a RPCSEC_GSS_CREATE message that successfully binds a client and a user
user security context. security context.
Clients using RPCSEC_GSS context binding MUST use, as the parent Clients using RPCSEC_GSSv3 compound authentication MUST use an
context handle, an RPCSEC_GSS context handle that corresponds to a RPCSEC_GSSv3 context handle that corresponds to a GSS-API security
GSS-API security context that authenticates the client host, and for context that authenticates the client host for the outer handle. The
the inner context handle it SHOULD use a context handle to inner context handle it SHOULD use a context handle to authenticate a
authenticate a user. The reverse (parent handle authenticates user, user. The reverse (outer handle authenticates user, inner
inner authenticates client) MUST NOT be used. Other compounds might authenticates client) MUST NOT be used. Other compounds might
eventually make sense. eventually make sense.
An RPCSEC_GSSv3 context handle that is bound to another RPCSEC_GSS An inner RPCSEC_GSSv3 context handle that is bound to an outer
context MUST be treated by servers as authenticating the GSS-API RPCSEC_GSS context MUST be treated by servers as authenticating the
initiator principal authenticated by the inner context handle's GSS- GSS-API initiator principal authenticated by the inner context
API security context. This principal may be mapped to a server-side handle's GSS- API security context. This principal may be mapped to
notion of user or principal. a server-side notion of user or principal.
2.3.1.2. Channel Binding
RPCSEC_GSSv3 provides a different way to do channel binding than
RPCSEC_GSSv2. Specifically:
a. RPCSEC_GSSv3 builds on RPCSEC_GSSv1 by reusing existing,
established context handles rather than providing a different RPC
security flavor for establishing context handles,
b. channel bindings data are not hashed because the community now
agrees that it is the secure channel's responsibility to produce
channel bindings data of manageable size.
(a) is useful in keeping RPCSEC_GSSv3 simple in general, not just for
channel binding. (b) is useful in keeping RPCSEC_GSSv3 simple
specifically for channel binding.
Channel binding is accomplished as follows. The client prefixes the
channel bindings data octet string with the channel type as described
in [5], then the client calls GSS_GetMIC() to get a MIC of resulting
octet string, using the parent RPCSEC_GSS context handle's GSS-API
security context. The MIC is then placed in the chan_binding_mic
field of RPCSEC_GSS3_CREATE arguments (rpc_gss3_create_args).
If the chan_binding_mic field of the arguments of a 2.4.1.2. Label Assertions
RPCSEC_GSS3_CREATE control message is set, then the server MUST
verify the client's channel binding MIC if the server supports this
feature. If channel binding verification succeeds then the server
MUST generate a new MIC of the same channel bindings and place it in
the chan_binding_mic field of the RPCSEC_GSS3_CREATE results. If
channel binding verification fails or the server doesn't support
channel binding then the server MUST indicate this in its reply by
not including a chan_binding_mic value (chan_binding_mic is an
optional field).
The client MUST verify the result's chan_binding_mic value, if the <CODE BEGINS>
server included it, by calling GSS_VerifyMIC() with the given MIC and
the channel bindings data (including the channel type prefix). If
client-side channel binding verification fails then the client MUST
call RPCSEC_GSS3_DESTROY. If the client requested channel binding
but the server did not include a chan_binding_mic field in the
results, then the client MAY continue to use the resulting context
handle as though channel binding had never been requested, otherwise
(if the client really wanted channel binding) it MUST call
RPCSEC_GSS3_DESTROY.
As per-RPCSEC_GSSv2 [4]: /// struct rgss3_label {
/// rgss3_lfs rl_lfs;
/// opaque rl_label<>;
/// };
///
/// struct rgss3_lfs {
/// unsigned int rlf_lfs_id;
/// unsigned int rlf_pi_id;
/// };
///
"Once a successful [channel binding] procedure has been performed <CODE ENDS>
on an [RPCSEC_GSSv3] context handle, the initiator's
implementation may map application requests for rpc_gss_svc_none
and rpc_gss_svc_integrity to rpc_gss_svc_channel_prot credentials.
And if the secure channel has privacy enabled, requests for
rpc_gss_svc_privacy can also be mapped to
rpc_gss_svc_channel_prot."
Any RPCSEC_GSSv3 context handle that has been bound to a secure The client discovers which labels the server supports via the
channel in this way SHOULD be used only with the RPCSEC_GSS_LIST control message.
rpc_gss_svc_channel_prot, and SHOULD NOT be used with
rpc_gss_svc_none nor rpc_gss_svc_integrity -- if the secure channel
does not provide privacy protection then the client MAY use
rpc_gss_svc_privacy where privacy protection is needed or desired.
2.3.1.3. Label Assertions RPCSEC_GSSv3 clients MAY assert a server security label in some LSF
by binding a label assertion to the RPCSEC_GSSv3 context handle.
This is done by including an assertion of type rgss3_label in the
RPCSEC_GSS_CREATE rgss3_create_args rca_assertions call data.
RPCSEC_GSSv3 clients MAY assert a security label in some LSF by The labels that are accepted by the target and bound to the
binding this assertion into an RPCSEC_GSSv3 context handle. This is RPCSEC_GSSv3 context will be enumerated in the rcr_assertions field
done by including an assertion of type rpc_gss3_label in the of the rgss3_create_res RPCSEC_GSS_CREATE reply.
'assertions' field (discriminant: 'LABEL') of the RPCSEC_GSS3_CREATE
arguments to the desired LSF and label.
Label encoding is specified to mirror the NFSv4 sec_label attribute Label encoding is specified to mirror the NFSv4.2 sec_label attribute
described in Section 12.2.2 of [6]. The label format specifier (LFS) described in Section 12.2.2 of [6]. The label format specifier (LFS)
is an identifier used by the client to establish the syntactic format is an identifier used by the client to establish the syntactic format
of the security label and the semantic meaning of its components. of the security label and the semantic meaning of its components.
The policy identifier (PI) is an optional part of the definition of The policy identifier (PI) is an optional part of the definition of
an LFS which allows for clients and server to identify specific an LFS which allows for clients and server to identify specific
security policies. The opaque label field of rpc_gss3_label is security policies. The opaque label field of rgss3_label is
dependent on the MAC model to interpret and enforce. dependent on the MAC model to interpret and enforce.
[[Comment.7: Check that this Label definition provides all the Asserting a server supported label via RPCSEC_GSS_CREATE enables
server guest mode labels. Full mode is enabled when an
RPCSEC_GSS_CREATE label assertion is combined with asserting the same
label with the NFSv4.2 sec_label attribute.
[[Comment.2: Check that this Label discussion provides all the
required pieces to enable full mode when combined with NFSv4.2 LNFS. required pieces to enable full mode when combined with NFSv4.2 LNFS.
Specifically, how does the client find out and respond if a server Specifically, how does the client find out and respond if a server
has changed a label. --AA]] has changed a label. --AA]]
If a label itself requires privacy protection (i.e., that the user If a label itself requires privacy protection (i.e., that the user
can assert that label is a secret) then the client MUST use the can assert that label is a secret) then the client MUST use the
rpc_gss_svc_privacy protection service for the RPCSEC_GSS3_CREATE rpc_gss_svc_privacy protection service for the RPCSEC_GSS_CREATE
request or, if the parent handle is bound to a secure channel that request or, if the parent handle is bound to a secure channel that
provides privacy protection, rpc_gss_svc_channel_prot. provides privacy protection, rpc_gss_svc_channel_prot.
If a client wants to ensure that the server understands the asserted If a client wants to ensure that the server understands the asserted
label then it MUST set the 'critical' field of the label assertion to label then it MUST set the 'critical' field of the label assertion to
TRUE, otherwise it MUST set it to FALSE. TRUE, otherwise it MUST set it to FALSE.
Servers that do not support labeling MUST ignore non-critical label Servers that do not support labeling MUST ignore non-critical label
assertions. Servers that do not support the requested LFS MUST assertions. Servers that do not support the requested LFS MUST
either ignore non-critical label assertions or map them to a suitable either ignore non-critical label assertions or map them to a suitable
label in a supported LFS. Servers that do not support labeling or do label in a supported LFS. Servers that do not support labeling or do
not support the requested LFS MUST return an error if the label not support the requested LFS MUST return an error if the label
request is critical. Servers that support labeling in the requested request is critical. Servers that support labeling in the requested
LFS MAY map the requested label to different label as a result of LFS MAY map the requested label to different label as a result of
server-side policy evaluation. server-side policy evaluation.
2.3.1.4. Structured Privilege Assertions 2.4.1.3. Structured Privilege Assertions
A structured privilege is an RPC application defined structure that <CODE BEGINS>
is opaque, and is encoded in the rpc_gss3_privs privilege field.
Encoding, server verification and any server policies for structured
privileges are described by the RPC application definition.
A successful structured privilege assertion RPCSEC_GSS3_CREATE call ///
must return all granted privileges in the rpc_gss3_privs /// struct rgss3_privs {
granted_assertions field. /// string rp_name<>; /* human readable */
/// opaque rp_privilege<>;
/// };
<CODE ENDS>
A structured privilege is an RPC application defined privilege.
RPCSEC_GSSv3 clients MAY assert a structured privilege by binding the
privilege to the RPCSEC_GSSv3 context handle. This is done by
including an assertion of type rgss3_privs in the RPCSEC_GSS_CREATE
rgss3_create_args rca_assertions call data. Encoding, server
verification and any policies for structured privileges are described
by the RPC application definition.
A successful structured privilege assertion will be enumerated in the
rcr_assertions field of the rgss3_create_res RPCSEC_GSS_CREATE reply.
Section 3.4.1.2. "Inter-Server Copy with RPCSEC_GSSv3" of [6] shows Section 3.4.1.2. "Inter-Server Copy with RPCSEC_GSSv3" of [6] shows
an example of structured privilege definition and use. an example of structured privilege definition and use.
2.3.2. Destruction Request 2.4.1.4. Channel Binding
The RPCSEC_GSS3_DESTROY control message is the same as the <CODE BEGINS>
RPCSEC_GSSv1 RPCSEC_GSS_DESTROY control message, but with the version
3 header. Specifically, the rpc_gss_cred_vers_3_t fields in the RPC
Call opaque_auth use the GSS3 context handle and seq_num stream. As
with all RPCSEC_GSSv3 messages, the header checksum uses the parent
context, and needs to be valid.
The server sends a response as it would to a data request. The ///
client and server must then destroy the context for the session. /// typedef opaque rgss3_chan_binding<>;
///
2.3.3. List Request <CODE ENDS>
The RPCSEC_GSS3_LIST control message is similar to RPCSEC_GSS3_CREATE RPCSEC_GSSv3 provides a different way to do channel binding than
message. Specifically, the rpc_gss_cred_vers_3_t fields in the RPC RPCSEC_GSSv2 [4]. Specifically:
Call opaque_auth use the parent context handle and seq_num stream.
As with all RPCSEC_GSSv3 messages, the header checksum uses the
parent context, and needs to be valid.
The RPCSEC_GSS3_LIST control message consists of a single integer a. RPCSEC_GSSv3 builds on RPCSEC_GSSv1 by reusing existing,
indicating what should be listed, and the reply consists of an error established context handles rather than providing a different RPC
or the requested list. The client may query the server to list security flavor for establishing context handles,
available LFSs.
The result is an opaque octet string containing a list of LFSs b. channel bindings data are not hashed because the community now
[encoding TBD]. agrees that it is the secure channel's responsibility to produce
channel bindings data of manageable size.
2.3.4. Extensibility (a) is useful in keeping RPCSEC_GSSv3 simple in general, not just for
channel binding. (b) is useful in keeping RPCSEC_GSSv3 simple
specifically for channel binding.
Channel binding is accomplished as follows. The client prefixes the
channel bindings data octet string with the channel type as described
in [5], then the client calls GSS_GetMIC() to get a MIC of resulting
octet string, using the RPCSEC_GSSv3 context handle's GSS-API
security context. The MIC is then placed in the rca_chan_bind_mic
field of RPCSEC_GSS_CREATE arguments (rgss3_create_args).
If the rca_chan_bind_mic field of the arguments of a
RPCSEC_GSS_CREATE control message is set, then the server MUST verify
the client's channel binding MIC if the server supports this feature.
If channel binding verification succeeds then the server MUST
generate a new MIC of the same channel bindings and place it in the
rcr_chan_bind_mic field of the RPCSEC_GSS_CREATE rgss3_create_res
results. If channel binding verification fails or the server doesn't
support channel binding then the server MUST indicate this in its
reply by not including a rgss3_chan_binding value in rgss3_create_res
(rgss3_chan_binding is an optional field).
The client MUST verify the result's rcr_chan_bind_mic value by
calling GSS_VerifyMIC() with the given MIC and the channel bindings
data (including the channel type prefix). If client-side channel
binding verification fails then the client MUST call
RPCSEC_GSS_DESTROY. If the client requested channel binding but the
server did not include an rcr_chan_binding_mic field in the results,
then the client MAY continue to use the resulting context handle as
though channel binding had never been requested, otherwise (if the
client really wanted channel binding) it MUST call
RPCSEC_GSS_DESTROY.
As per-RPCSEC_GSSv2 [4]:
"Once a successful [channel binding] procedure has been performed
on an [RPCSEC_GSSv3] context handle, the initiator's
implementation may map application requests for rpc_gss_svc_none
and rpc_gss_svc_integrity to rpc_gss_svc_channel_prot credentials.
And if the secure channel has privacy enabled, requests for
rpc_gss_svc_privacy can also be mapped to
rpc_gss_svc_channel_prot."
Any RPCSEC_GSSv3 context handle that has been bound to a secure
channel in this way SHOULD be used only with the
rpc_gss_svc_channel_prot, and SHOULD NOT be used with
rpc_gss_svc_none nor rpc_gss_svc_integrity -- if the secure channel
does not provide privacy protection then the client MAY use
rpc_gss_svc_privacy where privacy protection is needed or desired.
2.4.2. New Control Procedure - RPCSEC_GSS_LIST
<CODE BEGINS>
/// enum rgss3_list_item {
/// LABEL = 0,
/// PRIVS = 1
/// };
///
/// struct rgss3_list_args {
/// rgss3_list_item rla_list_what<>;
/// };
///
/// union rgss3_list_item_u
/// switch (rgss3_list_item itype) {
/// case LABEL:
/// rgss3_label rli_labels<>;
/// case PRIVS:
/// rgss3_privs rli_privs<>;
/// default:
/// opaque rli_ext<>;
/// };
///
/// typedef rgss3_list_item_u rgss3_list_res<>;
///
<CODE ENDS>
The call data for an RPCSEC_GSS_LIST request consists of a list of
integers (rla_list_what<>) indicating what assertions to be listed,
and the reply consists of an error or the requested list.
[[Comment.3: What good is the rli_ext field? How should we describe
it's use? --AA]]
The result of requesting a list of rgss3_list_item LABEL is a list of
LFSs supported by the server. The client can then use the LFS list
to assert labels via the RPCSEC_GSS_CREATE label assertions. See
Section 2.4.1.2.
2.5. Extensibility
Assertion types may be added in the future by adding arms to the Assertion types may be added in the future by adding arms to the
'rpc_gss3_assertion_u' union. Every assertion has a 'critical' flag 'rgss3_assertion_u' union. Every assertion has a 'critical' flag
that can be used to indicate criticality. Other assertion types are that can be used to indicate criticality. Other assertion types are
described elsewhere and include: described elsewhere and include:
o Client-side assertions of identity: o Client-side assertions of identity:
* Primary client/user identity * Primary client/user identity
* Supplementary group memberships of the client/user, including * Supplementary group memberships of the client/user, including
support for specifying deltas to the membership list as seen on support for specifying deltas to the membership list as seen on
the server. the server.
New control message types may be added. New control message types may be added.
Servers receiving unknown critical client assertions MUST return an Servers receiving unknown critical client assertions MUST return an
error. error.
2.4. Data Messages 2.6. New auth_stat Values
RPCSEC_GSS3_DATA messages differ from from RPCSEC_GSSv1 data messages RPCSEC_GSSv3 requires the addition of several values to the auth_stat
in that the version number used MUST be '3' instead of '1'. As noted enumerated type definition:
in Section 2.2 the RPCSEC_GSSv3 context handle is used along with
it's sequence number stream.
For RPCSEC_GSSv3 data messages the rpc_gss_cred_vers_3_t in the RPC enum auth_stat {
message opaque_auth structure is encoded as follows: ...
/*
* RPCSEC_GSSv3 errors
*/
RPCSEC_GSS_COMPOUND_PROBLEM = <>,
RPCSEC_GSS_LABEL_PROBLEM = <>,
RPCSEC_GSS_UNKNOWN_PRIVILEGE = <>
RPCSEC_GSS_UNKNOWN_MESSAGE = <>
1. the union rpc_gss_cred_t version is set to 3 with the value being };
of type rpc_gss_cred_vers_3_t instead of rpc_gss_cred_vers_1_t.
2. the gss_proc is set to RPCSEC_GSS3_DATA [[Comment.4: fix above into YYY. All the entries are TBD... --NW]]
[[Comment.5: The compound authentication problems are: can't find the
handle plus handle version on the target, or the MIC of the nounce
does not match. Both of these errors already have auth_stat entries:
RPCSEC_GSS_CREDPROBLEM for the first and "reply status of
MSG_ACCEPTED, and an acceptance status of GARBAGE_ARGS." --AA]]
3. the seq_num is a valid GSS3 context (child context) sequence 3. Version Negotiation
number.
4. just as in RPCSEC_GSSv1, the rpc_gss_service_t is one of An initiator that supports version 3 of RPCSEC_GSS simply issues an
rpc_gss_svc_none, rpc_gss_svc_integrity, rpc_gss_svc_privacy, or RPCSEC_GSS request with the rgc_version field set to
rpc_gss_svc_channel_prot. RPCSEC_GSS_VERS_3. If the target does not recognize
RPCSEC_GSS_VERS_3, the target will return an RPC error per Section
5.1 of [2].
5. the handle field is set to the (child) RPCSEC_GSSv3 context The initiator MUST NOT attempt to use an RPCSEC_GSS handle returned
handle by version 3 of a target with version 1 or version 2 of the same
target. The initiator MUST NOT attempt to use an RPCSEC_GSS handle
returned by version 1 or version 2 of a target with version 3 of the
same target.
3. Security Considerations 4. Operational Recommendation for Deployment
RPCSEC_GSSv3 is a superset of RPCSEC_GSSv2 [4] which in turn is a
superset of RPCSEC_GSSv1 [2], and so can be used in all situations
where RPCSEC_GSSv1 or RPCSEC_GSSv2 is used. RPCSEC_GSSv3 should be
used when the new functionality is needed.
5. Security Considerations
This entire document deals with security issues. This entire document deals with security issues.
The RPCSEC_GSSv3 protocol allows for client-side assertions of data The RPCSEC_GSSv3 protocol allows for client-side assertions of data
that is relevant to server-side authorization decisions. These that is relevant to server-side authorization decisions. These
assertions must be evaludated by the server in the context of whether assertions must be evaludated by the server in the context of whether
the client and/or user are authenticated, whether compound the client and/or user are authenticated, whether compound
authentication was used, whether the client is trusted, what ranges authentication was used, whether the client is trusted, what ranges
of assertions are allowed for the client and the user (separately or of assertions are allowed for the client and the user (separately or
together), and any relevant server-side policy. together), and any relevant server-side policy.
skipping to change at page 17, line 48 skipping to change at page 17, line 30
particularly unlikely to work well. NFSv4.1 has the server use an particularly unlikely to work well. NFSv4.1 has the server use an
existing, client-initiated RPCSEC_GSS context handle to protect existing, client-initiated RPCSEC_GSS context handle to protect
server-initiated callback RPCs. The NFSv4.1 callback security scheme server-initiated callback RPCs. The NFSv4.1 callback security scheme
lacks all the problems of the NFSv4 scheme, however, it is important lacks all the problems of the NFSv4 scheme, however, it is important
that the server pick an appropriate RPCSEC_GSS context handle to that the server pick an appropriate RPCSEC_GSS context handle to
protect any callbacks. Specifically, it is important that the server protect any callbacks. Specifically, it is important that the server
use RPCSEC_GSS context handles which authenticate the client to use RPCSEC_GSS context handles which authenticate the client to
protect any callbacks relating to server state initiated by RPCs protect any callbacks relating to server state initiated by RPCs
protected by RPCSEC_GSSv3 contexts. protected by RPCSEC_GSSv3 contexts.
[[Comment.8: [Add text about interaction with GSS-SSV...] --NW]] [[Comment.6: [Add text about interaction with GSS-SSV...] --NW]]
[[Comment.9: I see no reason to use RPCSEC_GSSv3 contexts for NFSv4.x
back channel. --AA]]
[[Comment.10: Since GSS3 requires an RPCSEC_GSSv1 or v2 context
handle to establish a GSS3 context, SSV can not be used as this draft
is written.]]
[[Comment.11: AFAICS the reason to use SSV is to avoid using a client [[Comment.7: AFAICS the reason to use SSV is to avoid using a client
machine credential which means compound authentication can not be machine credential which means compound authentication can not be
used. Since GSS3 requires an RPCSEC_GSSv1 or v2 context handle to used. --AA]]
establish a GSS3 context, SSV can not be used as the parent context
for GSSv3. --AA]]
4. IANA Considerations 6. IANA Considerations
This section uses terms that are defined in [8]. This section uses terms that are defined in [8].
There are no IANA considerations in this document. TBDs in this There are no IANA considerations in this document. TBDs in this
document will be assigned by the ONC RPC registrar (which is not document will be assigned by the ONC RPC registrar (which is not
IANA, XXX: verify). IANA, XXX: verify).
5. References 7. References
5.1. Normative References 7.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", March 1997. Levels", RFC 2119, March 1997.
[2] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol [2] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol
Specification", RFC 2203, September 1997. Specification", RFC 2203, September 1997.
[3] Linn, J., "Generic Security Service Application Program [3] Linn, J., "Generic Security Service Application Program
Interface Version 2, Update 1", RFC 2743, January 2000. Interface Version 2, Update 1", RFC 2743, January 2000.
[4] Srinivasan, R., "RPC: Remote Procedure Call Protocol [4] Eisler, M., "RPCSEC_GSS Version 2", RFC 5403, February 2009.
Specification Version 2", RFC 1831, August 1995.
[5] Williams, N., "On the Use of Channel Bindings to Secure [5] Williams, N., "On the Use of Channel Bindings to Secure
Channels", RFC 5056, November 2007. Channels", RFC 5056, November 2007.
[6] Haynes, T., "NFS Version 4 Minor Version 2", [6] Haynes, T., "NFS Version 4 Minor Version 2",
draft-ietf-nfsv4-minorversion2-19 (Work In Progress), draft-ietf-nfsv4-minorversion2-21 (Work In Progress),
March 2013. March 2013.
[7] Eisler, M., "XDR: External Data Representation Standard", [7] Eisler, M., "XDR: External Data Representation Standard",
RFC 4506, May 2006. RFC 4506, May 2006.
[8] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [8] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. Considerations Section in RFCs", BCP 26, RFC 5226, May 2008.
5.2. Informative References 7.2. Informative References
[9] Haynes, T., "Requirements for Labeled NFS",
draft-ietf-nfsv4-labreqs-03 (work in progress).
[10] "Section 46.6. Multi-Level Security (MLS) of Deployment Guide: [9] "Section 46.6. Multi-Level Security (MLS) of Deployment Guide:
Deployment, configuration and administration of Red Hat Deployment, configuration and administration of Red Hat
Enterprise Linux 5, Edition 6", 2011. Enterprise Linux 5, Edition 6", 2011.
[11] Smalley, S., "The Distributed Trusted Operating System (DTOS) [10] Smalley, S., "The Distributed Trusted Operating System (DTOS)
Home Page", Home Page",
<http://www.cs.utah.edu/flux/fluke/html/dtos/HTML/dtos.html>. <http://www.cs.utah.edu/flux/fluke/html/dtos/HTML/dtos.html>.
[12] Carter, J., "Implementing SELinux Support for NFS", [11] Carter, J., "Implementing SELinux Support for NFS",
<http://www.nsa.gov/research/_files/selinux/papers/nfsv3.pdf>. <http://www.nsa.gov/research/_files/selinux/papers/nfsv3.pdf>.
[12] Haynes, T., "Requirements for Labeled NFS",
draft-ietf-nfsv4-labreqs-05 (work in progress).
[13] Quigley, D. and J. Lu, "Registry Specification for MAC Security [13] Quigley, D. and J. Lu, "Registry Specification for MAC Security
Label Formats", draft-quigley-label-format-registry (work in Label Formats", draft-quigley-label-format-registry (work in
progress), 2011. progress), 2011.
Appendix A. Acknowledgments Appendix A. Acknowledgments
Appendix B. RFC Editor Notes Appendix B. RFC Editor Notes
[RFC Editor: please remove this section prior to publishing this [RFC Editor: please remove this section prior to publishing this
document as an RFC] document as an RFC]
[RFC Editor: prior to publishing this document as an RFC, please [RFC Editor: prior to publishing this document as an RFC, please
replace all occurrences of RFCTBD10 with RFCxxxx where xxxx is the replace all occurrences of RFCTBD10 with RFCxxxx where xxxx is the
RFC number of this document] RFC number of this document]
Authors' Addresses Authors' Addresses
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