Network Working Group                                         K. Narayan
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                               D. Nelson
Expires: August 2, 2010                            Elbrys Networks, Inc.
                                                         R. Presuhn, Ed.
                                                                    None
                                                        January 29, 2010


   Extensions to View-based Access Control Model for use with RADIUS
                   draft-ietf-isms-radius-vacm-02.txt

Abstract

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols.  In particular, it
   describes a backward-compatible extension to the View-based Access
   Control Model (VACM) for SNMPv3 for use with RADIUS and other AAA
   services to provide authorization of MIB database access, and defines
   objects for managing this extension.  This extension is intended to
   be used in conjunction with secure SNMP Transport Models that
   facilitate RADIUS authentication, such as the Secure Shell Transport
   Model.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on August 2, 2010.

Copyright Notice



Narayan, et al.          Expires August 2, 2010                 [Page 1]


Internet-Draft             RADIUS Enabled VACM              January 2010


   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  General  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  The Internet-Standard Management Framework . . . . . . . . . .  4
   3.  Conventions  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     4.1.  System Block Diagram . . . . . . . . . . . . . . . . . . .  4
     4.2.  Using RADIUS with SNMP . . . . . . . . . . . . . . . . . .  5
   5.  Structure of the MIB Module  . . . . . . . . . . . . . . . . .  6
     5.1.  Textual Conventions  . . . . . . . . . . . . . . . . . . .  6
     5.2.  The extVacmCounters Subtree  . . . . . . . . . . . . . . .  6
     5.3.  The Notifications Subtree  . . . . . . . . . . . . . . . .  6
     5.4.  The Table Structures . . . . . . . . . . . . . . . . . . .  6
   6.  Relationship to Other MIB Modules  . . . . . . . . . . . . . .  7
     6.1.  Relationship to the VACM MIB . . . . . . . . . . . . . . .  7
       6.1.1.  Extended VACM for RADIUS Authorization . . . . . . . .  7
       6.1.2.  VACM Extension for RADIUS Authorization  . . . . . . .  7
         6.1.2.1.  Dynamic Update of VACM and Extended VACM MIB
                   Module Objects . . . . . . . . . . . . . . . . . .  7
         6.1.2.2.  Purging Volatile Entries in the Extended VACM
                   MIB Module . . . . . . . . . . . . . . . . . . . .  9
       6.1.3.  Elements of Procedure for Extended VACM  . . . . . . .  9
     6.2.  MIB modules required for IMPORTS . . . . . . . . . . . . . 10
   7.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . . 10
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 16
   10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 17
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
     11.2. Informative References . . . . . . . . . . . . . . . . . . 18
   Appendix A.  Open Issues . . . . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19




Narayan, et al.          Expires August 2, 2010                 [Page 2]


Internet-Draft             RADIUS Enabled VACM              January 2010


1.  Introduction

1.1.  General

   This memo specifies the integration of several protocols to
   operationally simplify the administration of the access rights
   granted to users of network management data.  In this environment:


   o  The View-Based Access Control Model (VACM) [RFC3415] provides a
      means to manage users' access rights to management information
      accessed using SNMP.

   o  The Simple Network Management Protocol version 3 (SNMPv3) provides
      message security services through the Security Subsystem.

   o  The Transport Subsystem for the Simple Network Management Protocol
      [RFC5590] defines a Transport Subsystem.

   o  The Transport Security Model for SNMP [RFC5591] defines a
      Transport Security Model.

   o  The Secure Shell Transport Model for SNMP [RFC5592] defines a
      Secure Shell Transport Model and Remote Authentication Dial-In
      User Service (RADIUS).

   o  RADIUS Usage for Simple Network Management Protocol (SNMP)
      Transport Models [RFC5608] defines a method for authenticating
      SNMPv3 users via RADIUS.


   It is possible to authenticate SNMPv3 messages via a RADIUS when
   those messages are sent over the SSH transport.  As originally
   envisioned, VACM authorizes a given SNMP transaction using on-device,
   pre-existing authorization configuration.  In order to leverage a
   centralized RADIUS service to its full extent, the access control
   decision in the Access Control Subsystem needs to be able to make use
   of authorization information received from RADIUS as well.  This
   document defines an extension to the View-based Access Control Model
   to obtain authorization information for an authenticated principal,
   from RADIUS.

   Additional introductory material on the RADIUS operational model and
   RADIUS usage with SNMP may be found in Sections 1.3 and 1.5 of
   [RFC5608].

   It is important to understand the SNMP architecture and the
   terminology of the architecture to understand where the Extended



Narayan, et al.          Expires August 2, 2010                 [Page 3]


Internet-Draft             RADIUS Enabled VACM              January 2010


   View-based Access Control Model described in this memo fits into the
   architecture and how it interacts with other subsystems and models
   within the architecture.  It is expected that reader will have also
   read and understood RFC3411 [RFC3411], RFC3412 [RFC3412], RFC3413
   [RFC3413], RFC3415 [RFC3415]and RFC3418 [RFC3418].  As this document
   describes an extension to VACM, a thorough understanding of RFC3415
   [RFC3415] is assumed.


2.  The Internet-Standard Management Framework

   For a detailed overview of the documents that describe the current
   Internet-Standard Management Framework, please refer to section 7 of
   RFC 3410 [RFC3410].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  MIB objects are generally
   accessed through the Simple Network Management Protocol (SNMP).
   Objects in the MIB are defined using the mechanisms defined in the
   Structure of Management Information (SMI).  This memo specifies a MIB
   module that is compliant to the SMIv2, which is described in STD 58,
   RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
   [RFC2580].


3.  Conventions

   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 RFC 2119 [RFC2119].


4.  Overview

4.1.  System Block Diagram

   A block diagram of the major system components referenced in this
   document may be useful to understanding the text that follows.













Narayan, et al.          Expires August 2, 2010                 [Page 4]


Internet-Draft             RADIUS Enabled VACM              January 2010


                                         +--------+
              +......................... |RADIUS  |....+
              .                          |Server  |    .
            Shared                       +--------+    .
            User                             |         .
            Credentials             RADIUS   |      Shared
              .                              |      RADIUS
              .                              |      Secret
              .                              |         .
     +-------------+                  +-----------------+
     | Network     |                  | RADIUS Client / |
     | Management  |       SNMP       | SNMP Engine /   |
     | Application |------------------| Network Device  |
     +-------------+       SSH        +-----------------+


                               Block Diagram

   This diagram illustrates that a network management application
   communicates with a network device, the managed entity, using SNMP
   over SSH.  The network devices uses RADIUS to communicate with a
   RADIUS Server to authenticate the network management application (or
   the user whose credentials that application provides) and to obtain
   authorization information related to access via SNMP for purpose of
   device management.  Other secure transport protocols might be used
   instead of SSH.

4.2.  Using RADIUS with SNMP

   There are two use cases for RADIUS support of management access via
   SNMP.  These are (a) service authorization and (b) access control
   authorization.  RADIUS almost always involves user authentication as
   prerequisite to authorization, and there is a user authentication
   phase for each of these two use cases.  The first use case is
   discussed in detail in [RFC5608].  The second use case is the subject
   of this document.  This document describes how RADIUS attributes and
   messages are applied to the specific application area of SNMP Access
   Control Models, and VACM in particular.

   This document assumes that Extended VACM will be used in conjunction
   with an SNMP secure Transport Model and the SNMP Transport Security
   Model.  The rationale for this assumption is as follows.  The RFC
   3411 SNMP architecture maintains strong modularity and separation of
   concerns, extending to separating user identity (authentication) from
   user database access rights (authorization).  The former is the
   business of the Security Subsystem and the latter is the business of
   the Access Control Subsystem.  RADIUS, on the other hand, allows for
   no such separation of authorization from authentication.  In order to



Narayan, et al.          Expires August 2, 2010                 [Page 5]


Internet-Draft             RADIUS Enabled VACM              January 2010


   use RADIUS with SNMP, binding of user authentication to user
   authorization must be achieved, without violating the modularity of
   the RFC 3411 SNMP architecture.

   RADIUS does support a limited form of Authorize-Only operations.  The
   RADIUS "Authorize Only" Service-Type Attribute can be specified in an
   Access-Request message, but only when accompanied by a RADIUS State
   Attribute, which contains an implementation specific "cookie"
   representing the successful outcome of a previous authentication
   transaction.  For that reason, it is not possible to completely
   separate the use of RADIUS by the Access Control Subsystem from the
   use of RADIUS by other subsystems.  This suggests that the most
   straightforward approach is to leverage the existing RADIUS usage, as
   documented in [RFC5608], and the tmStateReference cache, as
   documented in Section 5.2 of [RFC5590].

   This document also assumes that the detailed access control rules are
   pre-configued in the NAS.  Dynamic user authorization for MIB
   database access control, as defined herein, is limited to mapping the
   authenticated user to a pre-existing group, which in turn is mapped
   to the pre-existing rules.  The operative use case assumption is that
   roles within an organization (i.e. groups and rules) change
   infrequently while the users assigned to those roles change much more
   frequently.  It is the user to role mapping that is outsourced to the
   RADIUS server.


5.  Structure of the MIB Module

5.1.  Textual Conventions

   This MIB module makes use of the RowStatus, StorageType,
   SnmpAdminString, and SnmpSecurityModel textual conventions.

5.2.  The extVacmCounters Subtree

   The extVacmCounters subtree contains all of this module's counters.

5.3.  The Notifications Subtree

   No notifications are defined in this MIB module

5.4.  The Table Structures








Narayan, et al.          Expires August 2, 2010                 [Page 6]


Internet-Draft             RADIUS Enabled VACM              January 2010


6.  Relationship to Other MIB Modules

6.1.  Relationship to the VACM MIB

6.1.1.  Extended VACM for RADIUS Authorization

   This document will rely on implementation specific integration of the
   RADIUS client for user authentication and authorization.  Further, it
   will rely on implementation specific caching of MIB database access
   policy information, in the form of the RADIUS Management-Policy-Id
   Attribute, such that it will be available to Extended VACM.

   A NAS that is compliant to this specification, MUST treat any RADIUS
   Access-Accept message that provisions a specific policy for MIB
   database access control that cannot be provided as if an Access-
   Reject message had been received instead.

   The RADIUS Management-Policy-Id Attribute MUST be used in an Access-
   Accept message to provision a user-specific access control policy for
   use in conjunction with Extended VACM.  The syntax and semantics of
   the Management-Policy-Id attribute are described in Section 6.3 of
   [RFC5607].

   The intended use of the content of the Management-Policy-Id attribute
   is to provision a mapping between the authenticated user, associated
   with the secure transport session, and an access control group pre-
   provisioned in the VACM MIB module.  Details of this mapping are
   described in following sections.

6.1.2.  VACM Extension for RADIUS Authorization

   The extension to VACM [RFC3415] described in this document is a
   method for one or more of its MIB module objects to be dynamically
   provisioned based on information received from RADIUS, or some
   similar AAA service.  This extension requires no changes to the
   Abstract Service Interface (ASI) for the Access Control Subsystem,
   nor any changes in the Elements of Procedure (EOP) for VACM.  A new
   MIB module that augments the vacmSecurityToGroupTable is defined in
   this document, as well as supplemental EOP for Extended VACM to
   follow.  It does require that a module of code somewhere in the NAS
   be able to write to the VACM MIB module and Extended VACM MIB Module,
   and that it reliably and consistently do so in immediate response to
   access control policy information received from RADIUS.

6.1.2.1.  Dynamic Update of VACM and Extended VACM MIB Module Objects

   The implementation-dependent interface between the RADIUS Client
   function and the SNMP Engine is responsible for updating the



Narayan, et al.          Expires August 2, 2010                 [Page 7]


Internet-Draft             RADIUS Enabled VACM              January 2010


   vacmSecurityToGroupTable table within the VACM MIB Module [RFC3415]
   and the corresponding rows of the extVacmSecurityToGroupTable.
   Specifically, the RADIUS User-Name Attribute is used as the
   vacmSecurityName and the RADIUS Management-Policy-Id Attribute is
   used as the vacmGroupName.  The vacmSecurityModel is the encoding for
   the Transport Security Model.  The vacmSecurityToGroupStorageType
   should be (2) volatile.

   In creating a row entry in the vacmSecurityToGroupTable, there are
   three cases to consider:


   o  No existing row has a matching vacmSecurityName.

   o  An existing row has a matching vacmSecurityName.

   o  No additional rows can be created, e.g. because of resource
      constraints, etc.


   The second and third cases require special consideration.  The second
   case may represent a conflict between dynamic access control
   authorization from RADIUS and local access control configuration by a
   security administrator, e.g. via remote or local SNMP MIB module
   updates.  If one assumes that the security administrator
   intentionally configured a table entry for the "conflicting"
   vacmSecurityName, with full knowledge that it might over-ride dynamic
   authorization information from RADIUS, the right thing to do would be
   nothing.  That is to say, do not update the table based on RADIUS
   authorization information.  On the other hand, it is possible that
   the "name collision" is the result of a mistake, or the result of
   stale configuration information.

   The behavior specified for Extended VACM is to make no update to the
   vacmSecurityToGroupTable, and to increment the
   extVacmSecurityNameConflict counter.

   The third case is likely to be rare, and SHOULD result in a
   notification of some sort being logged for action by the system
   administrator.

   It is expected that the value of the RADIUS Management-Policy-Id
   Attribute match an existing vacmGroupName that can be sucessfully
   used as an index to the vacmAccessTable.  If no matching
   vacmGroupName exists, then the access control defaults to this will
   result in the default access rights of "no access", which is the
   desired result.  The NAS should increment the extVacmMissingGroupName
   counter, for troubleshooting purposes, as this most likely indicates



Narayan, et al.          Expires August 2, 2010                 [Page 8]


Internet-Draft             RADIUS Enabled VACM              January 2010


   an administrative misconfiguration.

   In addition to creating a new row in the vacmSecurityToGroupTable,
   the NAS creates a corresponding new row in the
   extVacmSecurityToGroupTable, using the same values for index as were
   used to create the row in the vacmSecurityToGroupTable.  The value of
   the extVacmRowCreatedBy object is set to RADIUS (1), and the value of
   extVacmRowLifetime is set to the value of the RADIUS Session-Timeout
   Attribute, if one was received by the RADIUS Client for this session,
   or to zero (0) otherwise.

6.1.2.2.  Purging Volatile Entries in the Extended VACM MIB Module

   When the secure transport session is torn down, disconnected or times
   out, any volatile table rows created in the vacmSecurityToGroup table
   by the Extended VACM function MUST be removed.  The mechanism to
   accomplish this task is implementation specific.

6.1.3.  Elements of Procedure for Extended VACM

   This section describes the Elements of Procedure for Extended VACM.
   The function of the VACM extension is to manage the creation and
   deletion of rows in the vacmSecurityToGroupTable, based on the
   outcome of RADIUS authorization.  All access control decision
   functions are taken by VACM, as defined in [RFC3415].  The EOP for
   VACM remains as listed in Section 3 of that document.

   When a RADIUS (or other AAA service) authorizes SNMP data access
   control for a user-authenticated secure transport session, the NAS
   causes the RADIUS provisioning information to be made available to
   the Extended VACM facility, which populates the
   vacmSecurityToGroupTable, as follows:

   1.  If the the RADIUS Management-Policy-Id Attribute is not
       available, increment the extVacmNoPolicy counter.  Do not create
       a table row.

   2.  If the the RADIUS Management-Policy-Id Attribute is available,
       and if no existing row has a vacmSecurityName matching the RADIUS
       User-Name Attribute, create a new row with the columns populated
       as follows:

       A.  vacmSecurityModel = (x) secureTransportSecurityModel

       B.  vacmSecurityName = RADIUS User-Name Attribute

       C.  vacmGroupName = RADIUS Management-Policy-Id Attribute




Narayan, et al.          Expires August 2, 2010                 [Page 9]


Internet-Draft             RADIUS Enabled VACM              January 2010


       D.  vacmSecurityToGroupStorageType = volatile(2)

       E.  vacmSecurityToGroupStatus = createAndGo ???

       F.  extVacmRowCreatedBy = (1)

       G.  extVacmRowLifetime = RADIUS Session-Timeout Attribute | zero
           (0)

       H.  extVacmTransportSessionID = ID provided by the Secure
           Transport Model

   3.  If an existing table row has a matching vacmSecurityName,
       increment the extVacmSecurityNameConflict counter.  Do not create
       a table row.  If no additional table rows can be created, e.g.
       because of resource constraints, increment the
       extVacmResourceError counter.

   When a RADIUS-authenticated secure transport session is disconnected
   by the remote peer, the NAS causes the Extended VACM to remove the
   corresponding table row from the vacmSecurityToGroupTable.  The NAS
   provides an implementation dependent identifier of the session in
   question to Extended VACM.


   1.  Search for a row with a matching extVacmTransportSessionID.

   2.  If found, check to see that the extVacmRowCreateby value is (1)
       radius.  If not, ignore the request.

   3.  If a table row exists with a matching value of
       extVACMTransportSessionID, that row is deleted.

6.2.  MIB modules required for IMPORTS

   The MIB module defined employs textual conventions from [RFC2579] and
   [RFC3411].


7.  Definitions



SNMP-EXT-VACM-MIB DEFINITIONS ::= BEGIN

IMPORTS
    MODULE-COMPLIANCE, OBJECT-GROUP       FROM SNMPv2-CONF
    MODULE-IDENTITY, OBJECT-TYPE,



Narayan, et al.          Expires August 2, 2010                [Page 10]


Internet-Draft             RADIUS Enabled VACM              January 2010


    mib-2,
    Unsigned32,
    Counter32                             FROM SNMPv2-SMI
    RowStatus, StorageType                FROM SNMPv2-TC
    SnmpAdminString,
    SnmpSecurityModel                     FROM SNMP-FRAMEWORK-MIB;

snmpExtVacmMIB    MODULE-IDENTITY
    LAST-UPDATED "200912020000Z"          -- 1 Dec. 2009, midnight
    ORGANIZATION "ISMS Working Group"
    CONTACT-INFO "WG-email:   isms@ietf.org"

    DESCRIPTION  "The management and local datstore information
                  definitions for the Extended View-based Access
                  Control Model for SNMP.

                  Copyright (C) The Internet Society (2009)."

    REVISION "200912020000Z"
    DESCRIPTION "Initial version,published as RFCZZZZ."
     ::= { mib-2 XXX }

extVacmMIBObjects   OBJECT IDENTIFIER ::= { snmpExtVacmMIB 1 }

extVacmMIBConformance OBJECT IDENTIFIER ::= {snmpExtVacmMIB 2 }

extVacmCounters     OBJECT IDENTIFIER ::= { extVacmMIBObjects 1 }

extVacmResourceError OBJECT-TYPE
       SYNTAX Counter32
       UNITS "lost rows"
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
             "The number of VACM Security Name to Security
             Group table rows that could not be created by
             Extended VACM because of insufficient resources."
       ::= { extVacmCounters 1 }

extVacmNoPolicy OBJECT-TYPE
       SYNTAX Counter32
       UNITS "lost rows"
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
             "The number of VACM Security Name to Security
             Group table rows that could not be created by
             Extended VACM because the AAA-provisioned



Narayan, et al.          Expires August 2, 2010                [Page 11]


Internet-Draft             RADIUS Enabled VACM              January 2010


             group policy did not match an existing row in
             the VACM access table."
       ::= { extVacmCounters 2 }

extVacmSecurityNameConflict OBJECT-TYPE
       SYNTAX Counter32
       UNITS "lost rows"
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
             "The number of VACM Security Name to Security
             Group table rows that could not be created by
             Extended VACM because the AAA-provisioned
             security name (user name) conflicted with an
             existing row in the table."
       ::= { extVacmCounters 3 }

extVacmSecurityToGroupTable OBJECT-TYPE
    SYNTAX       SEQUENCE OF ExtVacmSecurityToGroupEntry
    MAX-ACCESS   not-accessible
    STATUS       current
    DESCRIPTION "This table maps a combination of securityModel and
                 securityName into a groupName which is used to define
                 an access control policy for a group of principals."
    ::= { extVacmMIBObjects 2 }

extVacmSecurityToGroupEntry OBJECT-TYPE
    SYNTAX       ExtVacmSecurityToGroupEntry
    MAX-ACCESS   not-accessible
    STATUS       current
    DESCRIPTION "An entry in this table maps the combination of a
                 securityModel and securityName into a groupName."
    INDEX       {
                  extVacmSecurityModel,
                  extVacmSecurityName
                }
    ::= { extVacmSecurityToGroupTable 1 }

ExtVacmSecurityToGroupEntry ::= SEQUENCE
    {
        extVacmSecurityModel            SnmpSecurityModel,
        extVacmSecurityName             SnmpAdminString,
        extVacmGroupName                SnmpAdminString,
        extVacmSecurityToGroupStorageType  StorageType,
        extVacmSecurityToGroupStatus    RowStatus,
        extVacmRowCreatedBy             INTEGER,
        extVacmRowLifetime              Unsigned32,
        extVacmTransportSessionID       Unsigned32



Narayan, et al.          Expires August 2, 2010                [Page 12]


Internet-Draft             RADIUS Enabled VACM              January 2010


    }

extVacmSecurityModel OBJECT-TYPE
    SYNTAX       SnmpSecurityModel(1..2147483647)
    MAX-ACCESS   not-accessible
    STATUS       current
    DESCRIPTION "The Security Model, by which the vacmSecurityName
                 referenced by this entry is provided.
                 Note, this object may not take the 'any' (0) value."
    ::= { extVacmSecurityToGroupEntry 1 }

extVacmSecurityName OBJECT-TYPE
    SYNTAX       SnmpAdminString (SIZE(1..32))
    MAX-ACCESS   not-accessible
    STATUS       current
    DESCRIPTION "The securityName for the principal, represented in a
                 Security Model independent format, which is mapped by
                 this entry to a groupName."
    ::= { extVacmSecurityToGroupEntry 2 }

extVacmGroupName    OBJECT-TYPE
    SYNTAX       SnmpAdminString (SIZE(1..32))
    MAX-ACCESS   read-create
    STATUS       current
    DESCRIPTION "The name of the group to which this entry (e.g., the
                 combination of securityModel and securityName)
                 belongs.

                 This groupName is used as index into the
                 vacmAccessTable to select an access control policy.
                 A value in this table does not imply that an instance
                 with the value exists in table vacmAccesTable."
    ::= { extVacmSecurityToGroupEntry 3 }

extVacmSecurityToGroupStorageType OBJECT-TYPE
    SYNTAX       StorageType
    MAX-ACCESS   read-create
    STATUS       current
    DESCRIPTION "The storage type for this conceptual row.
                 Conceptual rows having the value 'permanent' need not
                 allow write-access to any columnar objects in the row."
    DEFVAL      { nonVolatile }
    ::= { extVacmSecurityToGroupEntry 4 }

extVacmSecurityToGroupStatus OBJECT-TYPE
    SYNTAX       RowStatus
    MAX-ACCESS   read-create
    STATUS       current



Narayan, et al.          Expires August 2, 2010                [Page 13]


Internet-Draft             RADIUS Enabled VACM              January 2010


    DESCRIPTION "The status of this conceptual row.

                 Until instances of all corresponding columns are
                 appropriately configured, the value of the
                 corresponding instance of the vacmSecurityToGroupStatus
                 column is 'notReady'.

                 In particular, a newly created row cannot be made
                 active until a value has been set for vacmGroupName.

                 The  RowStatus TC [RFC2579] requires that this
                 DESCRIPTION clause states under which circumstances
                 other objects in this row can be modified:

                 The value of this object has no effect on whether
                 other objects in this conceptual row can be modified."
    ::= { extVacmSecurityToGroupEntry 5 }

extVacmRowCreatedBy OBJECT-TYPE
    SYNTAX      INTEGER
                { radius (1), -- Row created by Extended VACM
                  other  (2)  -- ???
                }
    MAX-ACCESS   read-create
    STATUS       current
    DESCRIPTION "The source of the infromation in this row
                 is indicated by the value of this object.
                 In the case of VACM this column probably won't
                 exist."
    ::= { extVacmSecurityToGroupEntry 6 }

extVacmRowLifetime OBJECT-TYPE
    SYNTAX       Unsigned32
    UNITS        "seconds"
    MAX-ACCESS   read-create
    STATUS       current
    DESCRIPTION "The number of seconds remaining in this row's
                 lifetime.  Extended VACM SHOULD delete this
                 row when this value reaches zero."
    ::= { extVacmSecurityToGroupEntry 7 }

extVacmTransportSessionID OBJECT-TYPE
    SYNTAX       Unsigned32
    MAX-ACCESS   read-create
    STATUS       current
    DESCRIPTION "An identifier of the secure transport
                 model's session associated with this
                 authenticated user.  The identifier



Narayan, et al.          Expires August 2, 2010                [Page 14]


Internet-Draft             RADIUS Enabled VACM              January 2010


                 MUST be unique within the scope of the NAS.
                 It's content is implementation dependant
                 and it SHOULD be used merely as an index."
    ::= { extVacmSecurityToGroupEntry 8 }

-- Conformance information ******************************************

extVacmMIBCompliances
               OBJECT IDENTIFIER ::= {extVacmMIBConformance 1}
extVacmMIBGroups
               OBJECT IDENTIFIER ::= {extVacmMIBConformance 2}

-- compliance statements

extVacmMIBBasicCompliance MODULE-COMPLIANCE
    STATUS       current
    DESCRIPTION "The compliance statement for SNMP engines which
                 implement the Extensions to the View-based Access
                 Control Model for use with RADIUS.
                "
    MODULE    -- this module
        MANDATORY-GROUPS { extVacmGroup }

    ::= { extVacmMIBCompliances 1 }

-- units of conformance

extVacmGroup OBJECT-GROUP
    OBJECTS {
              extVacmResourceError,
              extVacmNoPolicy,
              extVacmSecurityNameConflict,
              extVacmGroupName,
              extVacmSecurityToGroupStorageType,
              extVacmSecurityToGroupStatus,
              extVacmRowCreatedBy,
              extVacmRowLifetime,
              extVacmTransportSessionID
            }
    STATUS       current
    DESCRIPTION "A collection of objects for supporting the use
                 of RADIUS to provide user / group mappings for VACM.
                "
    ::= { extVacmMIBGroups 1 }


END




Narayan, et al.          Expires August 2, 2010                [Page 15]


Internet-Draft             RADIUS Enabled VACM              January 2010


8.  Security Considerations

   TODO

   Some of the readable objects in this MIB module (i.e., objects with a
   MAX-ACCESS other than not-accessible) may be considered sensitive or
   vulnerable in some network environments.  It is thus important to
   control even GET and/or NOTIFY access to these objects and possibly
   to even encrypt the values of these objects when sending them over
   the network via SNMP.  These are the tables and objects and their
   sensitivity/vulnerability:


   o  TBD

   SNMP versions prior to SNMPv3 did not include adequate security.
   Even if the network itself is secure (for example by using IPsec),
   even then, there is no control as to who on the secure network is
   allowed to access and GET/SET (read/change/create/delete) the objects
   in this MIB module.

   It is RECOMMENDED that implementers consider the security features as
   provided by the SNMPv3 framework (see [RFC3410], section 8),
   including full support for the SNMPv3 cryptographic mechanisms (for
   authentication and privacy).

   Further, deployment of SNMP versions prior to SNMPv3 is NOT
   RECOMMENDED.  Instead, it is RECOMMENDED to deploy SNMPv3 and to
   enable cryptographic security.  It is then a customer/operator
   responsibility to ensure that the SNMP entity giving access to an
   instance of this MIB module is properly configured to give access to
   the objects only to those principals (users) that have legitimate
   rights to indeed GET or SET (change/create/delete) them.


9.  IANA Considerations

   The MIB module in this document uses the following IANA-assigned
   OBJECT IDENTIFIER values recorded in the SMI Numbers registry:



      Descriptor        OBJECT IDENTIFIER value
      ----------        -----------------------
      snmpExtVacmMIB    { mib-2 XXX }


   Editor's Note (to be removed prior to publication): the IANA is



Narayan, et al.          Expires August 2, 2010                [Page 16]


Internet-Draft             RADIUS Enabled VACM              January 2010


   requested to assign a value for "XXX" under the 'mib-2' subtree and
   to record the assignment in the SMI Numbers registry.  When the
   assignment has been made, the RFC Editor is asked to replace "XXX"
   (here and in the MIB module) with the assigned value and to remove
   this note.


10.  Contributors

   The following participants from the isms working group contributed to
   the devlopment of this document:

   o  David Harrington

   o  Juergen Schoenwaelder


11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2578]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Structure of Management Information
              Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.

   [RFC2579]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Textual Conventions for SMIv2",
              STD 58, RFC 2579, April 1999.

   [RFC2580]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Conformance Statements for SMIv2", STD 58, RFC 2580,
              April 1999.

   [RFC3411]  Harrington, D., Presuhn, R., and B. Wijnen, "An
              Architecture for Describing Simple Network Management
              Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
              December 2002.

   [RFC3415]  Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based
              Access Control Model (VACM) for the Simple Network
              Management Protocol (SNMP)", STD 62, RFC 3415,
              December 2002.

   [RFC5590]  Harrington, D. and J. Schoenwaelder, "Transport Subsystem
              for the Simple Network Management Protocol (SNMP)",



Narayan, et al.          Expires August 2, 2010                [Page 17]


Internet-Draft             RADIUS Enabled VACM              January 2010


              RFC 5590, June 2009.

   [RFC5591]  Harrington, D. and W. Hardaker, "Transport Security Model
              for the Simple Network Management Protocol (SNMP)",
              RFC 5591, June 2009.

   [RFC5607]  Nelson, D. and G. Weber, "Remote Authentication Dial-In
              User Service (RADIUS) Authorization for Network Access
              Server (NAS) Management", RFC 5607, July 2009.

   [RFC5608]  Narayan, K. and D. Nelson, "Remote Authentication Dial-In
              User Service (RADIUS) Usage for Simple Network Management
              Protocol (SNMP) Transport Models", RFC 5608, August 2009.

11.2.  Informative References

   [RFC3410]  Case, J., Mundy, R., Partain, D., and B. Stewart,
              "Introduction and Applicability Statements for Internet-
              Standard Management Framework", RFC 3410, December 2002.

   [RFC3412]  Case, J., Harrington, D., Presuhn, R., and B. Wijnen,
              "Message Processing and Dispatching for the Simple Network
              Management Protocol (SNMP)", STD 62, RFC 3412,
              December 2002.

   [RFC3413]  Levi, D., Meyer, P., and B. Stewart, "Simple Network
              Management Protocol (SNMP) Applications", STD 62,
              RFC 3413, December 2002.

   [RFC3418]  Presuhn, R., "Management Information Base (MIB) for the
              Simple Network Management Protocol (SNMP)", STD 62,
              RFC 3418, December 2002.

   [RFC5592]  Harrington, D., Salowey, J., and W. Hardaker, "Secure
              Shell Transport Model for the Simple Network Management
              Protocol (SNMP)", RFC 5592, June 2009.


Appendix A.  Open Issues

   This section identifies questions and issues that have not been
   addressed in this version of this document.  This section will
   probably be removed prior to publication, since there will be no
   questions left to address.

   1.  Is this document an amendment or update to RFC 3514?  Or is it
       simply a standalone document that describes how to provision
       certain MIB Objects defined in RFC 3514, along with an extended



Narayan, et al.          Expires August 2, 2010                [Page 18]


Internet-Draft             RADIUS Enabled VACM              January 2010


       set of augmenting table columns?

   2.  Does this document need to make any reference to the Elements of
       Procedure in RFC 3514, or does is simply need its own Elements of
       Procedure for updating the group mapping table?

   3.  Dave Harrington had issued a summary email after IETF75
       containing apparently contradictory statements about whether the
       additional columns should be in the *same* table that VACM uses
       or in another, separate table that augments the VACM table.
       Basically, we need some help in actually structuring the new MIB
       Module.

   4.  The Groups and Conformance sections of the MIB Module need to be
       checked and kept in alignment with the definitions.

   5.  Make sure that the new Elements of Procedure make sense and cover
       all the corner cases correctly.

   6.  for session tracking use tlstmSessionID?

   7.  Make boilerplate in MIB module agree with the legal trust
       incantation du jour.

   8.  Security considerations need to be filled in, specifically
       concerning trust relationships to RADIUS and the interaction with
       statically configured policy.


Authors' Addresses

   Kaushik Narayan
   Cisco Systems, Inc.
   10 West Tasman Drive
   San Jose, CA  95134
   USA

   Phone: +1.408.526.8168
   Email: kaushik_narayan@yahoo.com












Narayan, et al.          Expires August 2, 2010                [Page 19]


Internet-Draft             RADIUS Enabled VACM              January 2010


   David Nelson
   Elbrys Networks, Inc.
   282 Corporate Drive, Unit #1,
   Portsmouth, NH  03801
   USA

   Phone: +1.603.570.2636
   Email: d.b.nelson@comcast.net


   Randy Presuhn (editor)
   None

   Email: randy_presuhn@mindspring.com





































Narayan, et al.          Expires August 2, 2010                [Page 20]