draft-ietf-netconf-access-control-04.txt		draft-ietf-netconf-access-control-05.txt
	Internet Engineering Task Force A. Bierman		Internet Engineering Task Force A. Bierman
	Internet-Draft Brocade		Internet-Draft Brocade
	Intended status: Standards Track M. Bjorklund		Intended status: Standards Track M. Bjorklund
	Expires: December 16, 2011 Tail-f Systems		Expires: April 6, 2012 Tail-f Systems
	June 14, 2011		October 4, 2011
	Network Configuration Protocol Access Control Model		Network Configuration Protocol (NETCONF) Access Control Model
	draft-ietf-netconf-access-control-04		draft-ietf-netconf-access-control-05
	Abstract		Abstract
	The standardization of network configuration interfaces for use with		The standardization of network configuration interfaces for use with
	the NETCONF protocol requires a structured and secure operating		the NETCONF protocol requires a structured and secure operating
	environment that promotes human usability and multi-vendor		environment that promotes human usability and multi-vendor
	interoperability. There is a need for standard mechanisms to		interoperability. There is a need for standard mechanisms to
	restrict NETCONF protocol access for particular users to a pre-		restrict NETCONF protocol access for particular users to a pre-
	configured subset of all available NETCONF operations and content.		configured subset of all available NETCONF protocol operations and
	This document discusses requirements for a suitable access control		content. This document defines such an access control model.
	model, and provides one solution that meets these requirements.
	Status of this Memo		Status of this Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on December 16, 2011.		This Internet-Draft will expire on April 6, 2012.
	Copyright Notice		Copyright Notice
	Copyright (c) 2011 IETF Trust and the persons identified as the		Copyright (c) 2011 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	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 . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1.1. Requirements Notation . . . . . . . . . . . . . . . . 4
	1.1.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . 4
	1.1.3. YANG Terms . . . . . . . . . . . . . . . . . . . . . . 5
	1.1.4. NACM Terms . . . . . . . . . . . . . . . . . . . . . . 5
	2. Access Control Design Objectives . . . . . . . . . . . . . . . 6		2. Access Control Design Objectives . . . . . . . . . . . . . . . 6
	2.1. Protocol Control Points . . . . . . . . . . . . . . . . . 6		2.1. Access Control Points . . . . . . . . . . . . . . . . . . 6
	2.2. Simplicity . . . . . . . . . . . . . . . . . . . . . . . . 7		2.2. Simplicity . . . . . . . . . . . . . . . . . . . . . . . . 7
	2.3. Procedural Interface . . . . . . . . . . . . . . . . . . . 7		2.3. Procedural Interface . . . . . . . . . . . . . . . . . . . 7
	2.4. Datastore Access . . . . . . . . . . . . . . . . . . . . . 8		2.4. Datastore Access . . . . . . . . . . . . . . . . . . . . . 7
	2.4.1. Access Rights . . . . . . . . . . . . . . . . . . . . 8		2.5. Users and Groups . . . . . . . . . . . . . . . . . . . . . 7
	2.4.2. <get> and <get-config> Operations . . . . . . . . . . 8		2.6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . 8
	2.4.3. <edit-config> Operation . . . . . . . . . . . . . . . 9		2.7. Configuration Capabilities . . . . . . . . . . . . . . . . 8
	2.4.4. <copy-config> Operation . . . . . . . . . . . . . . . 10		2.8. Identifying Security-Sensitive Content . . . . . . . . . . 8
	2.5. Users and Groups . . . . . . . . . . . . . . . . . . . . . 10		3. NETCONF Access Control Model (NACM) . . . . . . . . . . . . . 10
	2.6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . 11		3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 10
	2.7. Configuration Capabilities . . . . . . . . . . . . . . . . 11		3.1.1. Features . . . . . . . . . . . . . . . . . . . . . . . 10
	2.8. Identifying Security Holes . . . . . . . . . . . . . . . . 11		3.1.2. External Dependencies . . . . . . . . . . . . . . . . 11
	2.9. Data Shadowing . . . . . . . . . . . . . . . . . . . . . . 12		3.1.3. Message Processing Model . . . . . . . . . . . . . . . 11
	2.10. NETCONF Specific Requirements . . . . . . . . . . . . . . 12		3.2. Datastore Access . . . . . . . . . . . . . . . . . . . . . 13
	3. NETCONF Access Control Model (NACM) . . . . . . . . . . . . . 14		3.2.1. Access Rights . . . . . . . . . . . . . . . . . . . . 13
	3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 14		3.2.2. <get> and <get-config> Operations . . . . . . . . . . 14
	3.1.1. Features . . . . . . . . . . . . . . . . . . . . . . . 14		3.2.3. <edit-config> Operation . . . . . . . . . . . . . . . 14
	3.1.2. External Dependencies . . . . . . . . . . . . . . . . 15		3.2.4. <copy-config> Operation . . . . . . . . . . . . . . . 15
	3.1.3. Message Processing Model . . . . . . . . . . . . . . . 15		3.2.5. <delete-config> Operation . . . . . . . . . . . . . . 16
	3.2. Model Components . . . . . . . . . . . . . . . . . . . . . 17		3.2.6. <commit> Operation . . . . . . . . . . . . . . . . . . 16
	3.2.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 17		3.2.7. <discard-changes> Operation . . . . . . . . . . . . . 16
	3.2.2. Groups . . . . . . . . . . . . . . . . . . . . . . . . 17		3.2.8. <kill-session> Operation . . . . . . . . . . . . . . . 16
	3.2.3. Sessions . . . . . . . . . . . . . . . . . . . . . . . 18		3.3. Model Components . . . . . . . . . . . . . . . . . . . . . 16
	3.2.4. Access Permissions . . . . . . . . . . . . . . . . . . 18		3.3.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 16
	3.2.5. Global Enforcement Controls . . . . . . . . . . . . . 18		3.3.2. Groups . . . . . . . . . . . . . . . . . . . . . . . . 17
	3.2.5.1. enable-nacm Switch . . . . . . . . . . . . . . . . 18		3.3.3. Global Enforcement Controls . . . . . . . . . . . . . 17
	3.2.5.2. read-default Switch . . . . . . . . . . . . . . . 19		3.3.3.1. enable-nacm Switch . . . . . . . . . . . . . . . . 17
	3.2.5.3. write-default Switch . . . . . . . . . . . . . . . 19		3.3.3.2. read-default Switch . . . . . . . . . . . . . . . 17
	3.2.5.4. exec-default Switch . . . . . . . . . . . . . . . 19		3.3.3.3. write-default Switch . . . . . . . . . . . . . . . 18
	3.2.6. Access Control Rules . . . . . . . . . . . . . . . . . 20		3.3.3.4. exec-default Switch . . . . . . . . . . . . . . . 18
	3.3. Access Control Enforcement Procedures . . . . . . . . . . 20		3.3.4. Access Control Rules . . . . . . . . . . . . . . . . . 18
	3.3.1. Initial Operation . . . . . . . . . . . . . . . . . . 20		3.4. Access Control Enforcement Procedures . . . . . . . . . . 19
	3.3.2. Session Establishment . . . . . . . . . . . . . . . . 21		3.4.1. Initial Operation . . . . . . . . . . . . . . . . . . 19
	3.3.3. "access-denied" Error Handling . . . . . . . . . . . . 21		3.4.2. Session Establishment . . . . . . . . . . . . . . . . 19
	3.3.4. Incoming RPC Message Validation . . . . . . . . . . . 21		3.4.3. "access-denied" Error Handling . . . . . . . . . . . . 19
	3.3.5. Data Node Access Validation . . . . . . . . . . . . . 24		3.4.4. Incoming RPC Message Validation . . . . . . . . . . . 20
	3.3.6. Outgoing <notification> Authorization . . . . . . . . 26		3.4.5. Data Node Access Validation . . . . . . . . . . . . . 22
	3.4. Data Model Definitions . . . . . . . . . . . . . . . . . . 28		3.4.6. Outgoing <notification> Authorization . . . . . . . . 24
	3.4.1. Data Organization . . . . . . . . . . . . . . . . . . 28
	3.4.2. YANG Module . . . . . . . . . . . . . . . . . . . . . 29		3.5. Data Model Definitions . . . . . . . . . . . . . . . . . . 26
	3.5. IANA Considerations . . . . . . . . . . . . . . . . . . . 38		3.5.1. Data Organization . . . . . . . . . . . . . . . . . . 27
	3.6. Security Considerations . . . . . . . . . . . . . . . . . 39		3.5.2. YANG Module . . . . . . . . . . . . . . . . . . . . . 27
			3.6. IANA Considerations . . . . . . . . . . . . . . . . . . . 37
			3.7. Security Considerations . . . . . . . . . . . . . . . . . 37
			3.7.1. NACM Configuration and Monitoring Considerations . . . 37
			3.7.2. General Configuration Issues . . . . . . . . . . . . . 39
			3.7.3. Data Model Design Considerations . . . . . . . . . . . 40
	4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 41		4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 41
	4.1. Normative References . . . . . . . . . . . . . . . . . . . 41		4.1. Normative References . . . . . . . . . . . . . . . . . . . 41
	4.2. Informative References . . . . . . . . . . . . . . . . . . 41		4.2. Informative References . . . . . . . . . . . . . . . . . . 41
	Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 42		Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 42
	A.1. <groups> Example . . . . . . . . . . . . . . . . . . . . . 42		A.1. <groups> Example . . . . . . . . . . . . . . . . . . . . . 42
	A.2. Module Rule Example . . . . . . . . . . . . . . . . . . . 43		A.2. Module Rule Example . . . . . . . . . . . . . . . . . . . 43
	A.3. RPC Rule Example . . . . . . . . . . . . . . . . . . . . . 44		A.3. RPC Rule Example . . . . . . . . . . . . . . . . . . . . . 44
	A.4. Data Rule Example . . . . . . . . . . . . . . . . . . . . 46		A.4. Data Rule Example . . . . . . . . . . . . . . . . . . . . 46
	A.5. Notification Rule Example . . . . . . . . . . . . . . . . 48		A.5. Notification Rule Example . . . . . . . . . . . . . . . . 48
	Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 50		Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 50
	B.1. 03-04 . . . . . . . . . . . . . . . . . . . . . . . . . . 50		B.1. 04-05 . . . . . . . . . . . . . . . . . . . . . . . . . . 50
	B.2. 02-03 . . . . . . . . . . . . . . . . . . . . . . . . . . 50		B.2. 03-04 . . . . . . . . . . . . . . . . . . . . . . . . . . 50
	B.3. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 50		B.3. 02-03 . . . . . . . . . . . . . . . . . . . . . . . . . . 50
	B.4. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 50		B.4. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 51
	B.5. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51		B.5. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 51
			B.6. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 52		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 52
	1. Introduction		1. Introduction
	The NETCONF protocol does not provide any standard mechanisms to		The NETCONF protocol does not provide any standard mechanisms to
	restrict the operations and content that each user is authorized to		restrict the protocol operations and content that each user is
	use.		authorized to access.
	There is a need for inter-operable management of the controlled		There is a need for inter-operable management of the controlled
	access to operator selected portions of the available NETCONF content		access to administrator selected portions of the available NETCONF
	within a particular server.		content within a particular server.
	This document addresses access control mechanisms for the Operation		This document addresses access control mechanisms for the Operation
	and Content layers of NETCONF, as defined in		and Content layers of NETCONF, as defined in [RFC6241]. It contains
	[I-D.ietf-netconf-4741bis], and [RFC5277]. It contains three main		three main sections:
	sections:
	1. Access Control Design Objectives		1. Access Control Design Objectives
	2. NETCONF Access Control Model (NACM)		2. NETCONF Access Control Model (NACM)
	3. YANG Data Model (ietf-netconf-acm.yang)		3. YANG Data Model (ietf-netconf-acm.yang)
	1.1. Terminology		1.1. Terminology
	1.1.1. Requirements Notation
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	1.1.2. NETCONF Terms		The following terms are defined in [RFC6241] and are not redefined
			here:
	The following terms are defined in [I-D.ietf-netconf-4741bis] and are
	not redefined here:
	o client		o client
	o datastore		o datastore
	o operation
	o protocol operation		o protocol operation
	o server		o server
	o session		o session
	o user		o user
	1.1.3. YANG Terms
	The following terms are defined in [RFC6020] and are not redefined		The following terms are defined in [RFC6020] and are not redefined
	here:		here:
	o data node		o data node
	o data definition statement		o data definition statement
	1.1.4. NACM Terms
	The following terms are used throughout this documentation:		The following terms are used throughout this documentation:
	access control: A security feature provided by the NETCONF server,		access control: A security feature provided by the NETCONF server,
	that allows an operator to restrict access to a subset of all		that allows an administrator to restrict access to a subset of all
	NETCONF protocol operations and data, based on various criteria.		NETCONF protocol operations and data, based on various criteria.
	access control model (ACM): A conceptual model used to configure and		access control model (ACM): A conceptual model used to configure and
	monitor the access control procedures desired by the operator to		monitor the access control procedures desired by the administrator
	enforce a particular access control policy.		to enforce a particular access control policy.
	access control rule: The conceptual criteria used to determine if a		access control rule: The criteria used to determine if a particular
	particular NETCONF protocol operation will be permitted or denied.		NETCONF protocol operation will be permitted or denied.
	access operation: How a request attempts to access a conceptual		access operation: How a request attempts to access a conceptual
	object. One of "read", "create", "delete", "update", and		object. One of "none", "read", "create", "delete", "update", and
	"execute".		"execute".
	recovery session: A special administrative session that is given		recovery session: A special administrative session that is given
	unlimited NETCONF access, and is exempt from all access control		unlimited NETCONF access, and is exempt from all access control
	enforcement. The specific mechanism(s) used by an implementation		enforcement. The mechanism(s) used by a server to control and
	to control and identify whether a session is a recovery session or		identify whether a session is a recovery session or not are
	not are outside the scope of this document.		implementation-specific and outside the scope of this document.
			write access: A shorthand for the "create", "delete", and "update"
			access operations.
	2. Access Control Design Objectives		2. Access Control Design Objectives
	[Editor's note: some things described here are requirements (MUST,		This section documents the design objectives for the NETCONF Access
	SHOULD, etc), but some things are descriptions how NACM works, e.g.		Control Model presented in Section 3.
	2.4.1, 2.4.3...]
	2.1. Protocol Control Points		2.1. Access Control Points
	The NETCONF protocol allows new operations to be added at any time,		NETCONF allows new protocol operations to be added at any time, and
	and the YANG data modeling language supports this feature. It is not		the YANG data modeling language supports this feature. It is not
	possible to design an ACM for NETCONF which only focuses on a static		possible to design an ACM for NETCONF that only focuses on a static
	set of operations, like some other protocols. Since few assumptions		set of protocol operations, like some other protocols. Since few
	can be made about an arbitrary protocol operation, the NETCONF		assumptions can be made about an arbitrary protocol operation, the
	architectural server components need to be protected at several		NETCONF architectural server components need to be protected at three
	conceptual control points.		conceptual control points.
	+-------------+ +-------------+		+-------------+ +-------------+
	client | protocol | | prune | client		client | protocol | | data node |
	request --> | operation | | restricted | ---> reply		request --> | operation | -------------> | access |
	| allowed? | | <rpc-reply> |		| allowed? | datastore | allowed? |
	+-------------+ | nodes? |		+-------------+ or state +-------------+
	| +-------------+		data access
	| if any datastore or
	| state data is accessed
	| by the operation
	V
	+-------------+ +----------------+
	| data node | | prune |
	| access | | restricted |
	| allowed? | | <notification> | ---> client
	+-------------+ | event or data? | session
	+----------------+
	Figure 1		+----------------+
			| notification |
			event --> | allowed? |
			+----------------+
	The following access control points are defined:		Figure 1
	protocol operation: Configurable permission to invoke specific		The following access control points, described in Figure 1, are
	protocol operations is required. Wildcard or multiple target		identified:
	mechanisms to reduce configuration and effort are also required.
	NETCONF datastore: Configurable permission to read and/or alter		protocol operation: Permission to invoke specific protocol
	specific data nodes within any conceptual datastore is required.		operations.
	Wildcard or multiple target mechanisms to reduce configuration and
	effort are also required.
	RPC Reply Content: Configurable permission to read specific data		datastore: Permission to read and/or alter specific data nodes
	nodes within any conceptual RPC output section is required.		within any datastore.
	Unauthorized data is silently omitted from the reply, instead of
	dropping the reply or sending an "access-denied" error.
	Notification Content: Configurable permission to receive specific		notification: Permission to receive specific notification event
	notification event types is required.		types.
	2.2. Simplicity		2.2. Simplicity
	Experience has shown that a complicated ACM will not be widely		Experience has shown that a complicated ACM will not be widely
	deployed, because it is too hard to use. The key factor that is		deployed, because it is too hard to use. The key factor that is
	ignored in such solutions is the concept of "localized cost". It		ignored in such solutions is the concept of "localized cost". It
	needs to be easy to do simple things, and possible to do complex		needs to be easy to do simple things, and possible to do complex
	things, instead of hard to do everything.		things, instead of hard to do everything.
	Configuration of the access control system needs to be as simple as		Configuration of the access control system needs to be as simple as
	possible. Simple and common tasks need to be easy to configure, and		possible. Simple and common tasks need to be easy to configure, and
	require little expertise or domain-specific knowledge. Complex tasks		require little expertise or domain-specific knowledge. Complex tasks
	are possible using additional mechanisms, which may require		are possible using additional mechanisms, which may require
	additional expertise.		additional expertise.
	A single set of access control rules SHOULD be able to control all		A single set of access control rules ought to be able to control all
	types of NETCONF protocol operation invocation, all conceptual		types of NETCONF protocol operation invocation, all datastore access,
	datastore access, and all NETCONF session output.		and all notification events.
	Access control SHOULD be defined with a small and familiar set of		Access control ought to be defined with a small and familiar set of
	permissions, while still allowing full control of NETCONF datastore		permissions, while still allowing full control of NETCONF datastore
	access.		access.
	Access control does not need to be applied to NETCONF <hello>
	messages.
	2.3. Procedural Interface		2.3. Procedural Interface
	The NETCONF protocol uses a procedural interface model, and an		The NETCONF protocol uses a remote procedure call model, and an
	extensible set of protocol operations. Access control for any		extensible set of protocol operations. Access control for any
	possible protocol operation is required.		possible protocol operation is necessary.
	It MUST be possible to configure the ACM to permit or deny access to
	specific NETCONF operations.
	YANG modules SHOULD be designed so that different access levels for
	input parameters to protocol operations is not required. Use of
	generic operations should be avoided, and separate operations defined
	instead, if different access levels are needed.
	2.4. Datastore Access		2.4. Datastore Access
	It MUST be possible to control access to specific nodes and subtrees		It is necessary to control access to specific nodes and subtrees
	within the conceptual NETCONF datastore.		within the NETCONF datastore, regardless of which protocol operation,
			standard or proprietary, was used to access the datastore.
	The same access control rules apply to all conceptual datastores.
	For example, the candidate configuration or the running
	configuration.
	Only the standard NETCONF datastores (candidate, running, and
	startup) are controlled by the ACM. Local or remote files or
	datastores accessed via the <url> parameter are optional to support.
	The non-volatile startup configuration needs to be loaded at boot-
	time into the running configuration without applying any access
	control rules. Access control is applied after the server has
	booted, and user sessions are active.
	2.4.1. Access Rights
	A small set of hard-wired datastore access rights is needed to
	control access to all possible NETCONF datastore operations,
	including vendor extensions to the standard operation set.
	The familiar "CRUDX" model can support all NETCONF operations:
	o Create: Allows the client to add a new data node instance to a
	datastore.
	o Read: Allows the client to read a data node instance from a
	datastore, or receive the notification event type.
	o Update: Allows the client to update an existing data node instance
	in a datastore.
	o Delete: Allows the client to delete a data node instance from a
	datastore.
	o eXec: Allows the client to execute the protocol operation.
	2.4.2. <get> and <get-config> Operations
	Data nodes to which the client does not have read access, either
	directly or via wildcard access, are silently omitted from the <rpc-
	reply> message. This is done to allow NETCONF filters for <get> and
	<get-config> to function properly, instead of causing an "access-
	denied" error because the filter criteria would otherwise include
	unauthorized read access to some data nodes. For NETCONF filtering
	purposes, the selection criteria is applied to the subset of nodes
	that the client is authorized to read, not the entire datastore.
	2.4.3. <edit-config> Operation
	The NACM access rights are not directly coupled to the <edit-config>
	"operation" attribute, although they are similar. Instead, a NACM
	access right applies to all operations which would result in a
	particular access operation to the target datastore. This section
	describes how these access rights apply to the specific datastore
	operations supported by the <edit-config> operation.
	If the effective operation is "none" (i.e., default-operation="none")
	for a particular data node, then no access control is applied to that
	data node.
	A "create", "merge", or "replace" operation on a datastore node which
	would result in the creation of a new data node instance, for which
	the user does not have "create" access permission, is rejected with
	an "access-denied" error.
	A "merge" or "replace" operation on a datastore node which would
	result in the modification of an existing data node instance, for
	which the user does not have "update" access permission, is rejected
	with an "access-denied" error.
	A "replace", "delete", or "remove" operation on a datastore node
	which would result in the deletion of an existing data node instance,
	for which the user does not have "delete" access permission, is
	rejected with an "access-denied" error.
	A "merge" operation may include data nodes which do not alter
	portions of the existing datastore. For example, a container or list
	node may be present for naming purposes, but does not actually alter
	the corresponding datastore node. These unaltered data nodes within
	the scope of a "merge" operation are ignored by the server, and do
	not require any access rights by the client.
	[Editor's note: ditto for "replace" (and copy-config...) Note that
	with this rule, a client w/o read access can guess db content by
	sending merge requests - if access-denied is not returned, it means
	the db has that value.]
	A "merge" operation may include data nodes, but not include
	particular child data nodes that are present in the datastore. These
	missing data nodes within the scope of a "merge" operation are
	ignored by the server, and do not require any access rights by the
	client.
	The contents of specific restricted datastore nodes MUST NOT be
	exposed in any <rpc-error> elements within the reply.
	2.4.4. <copy-config> Operation
	Access control for the <copy-config> operation requires special
	consideration because the operator is replacing the entire target
	datastore. Read access to the entire source datastore, and write
	access to the entire target datastore is needed for this operation to
	succeed.
	The server SHOULD determine the exact nodes in the target datastore
	which are actually different, and only check write access permissions
	for this set of nodes, which could be empty. For example, if a
	session can read the entire datastore, but only change one leaf, that
	session SHOULD be able to edit and save that one leaf. E.g., the
	<copy-config> operation from <running> to <startup> SHOULD succeed if
	the only effective changes are for data nodes that session is
	authorized to change.
	A client MUST have access to every datastore node, even ones that are
	not present in the source configuration data.
	For example, consider a common use-case such as a simple backup and
	restore procedure. The operator (client) MUST have full read access
	to the datastore in order to receive a complete copy of its contents.
	If the server simply omits these subtrees from the reply, and that
	copy is later used to restore the server datastore, the server will
	interpret the missing nodes as a request to delete those nodes, and
	return an error.
	2.5. Users and Groups		2.5. Users and Groups
	The server MUST obtain a user name from the underlying NETCONF		It is necessary that access control rules for a single user or a
	transport, such as an SSH user name.		configurable group of users can be configured.
	It MUST be possible to specify access control rules for a single user
	or a configurable group of users.
	The ACM MUST support the concept of administrative groups, to support		The ACM needs to support the concept of administrative groups, to
	the well-established distinction between a root account and other		support the well-established distinction between a root account and
	types of less-privileged conceptual user accounts. These groups MUST		other types of less-privileged conceptual user accounts. These
	be configurable by the operator.		groups needs to be configurable by the administrator.
	It MUST be possible to delegate the user-to-group mapping to a		It is necessary that the user-to-group mapping can be delegated to a
	central server, such as a RADIUS server [RFC2865] [RFC5607]. Since		central server, such as a RADIUS server [RFC2865] [RFC5607]. Since
	authentication is performed by the NETCONF transport layer, and		authentication is performed by the NETCONF transport layer, and
	RADIUS performs authentication and service authorization at the same		RADIUS performs authentication and service authorization at the same
	time, it MUST be possible for the underlying NETCONF transport to		time, the underlying NETCONF transport needs to be able to report a
	report a set of group names associated with the user to the server.		set of group names associated with the user to the server.
	2.6. Maintenance		2.6. Maintenance
	It SHOULD be possible to disable part or all of the access control		It ought to be possible to disable part or all of the access control
	model without deleting any configuration.		model without deleting any access control rules.
	2.7. Configuration Capabilities		2.7. Configuration Capabilities
	Suitable control and monitoring mechanisms are needed to allow an		Suitable configuration and monitoring mechanisms are needed to allow
	operator to easily manage all aspects of the ACM behavior. A		an administrator to easily manage all aspects of the ACM behavior. A
	standard data model, suitable for use with the <edit-config>		standard data model, suitable for use with the <edit-config> protocol
	operation MUST be available for this purpose.		operation needs to be available for this purpose.
	Access control rules to restrict operations on specific subtrees		Access control rules to restrict access operations on specific
	within the configuration datastore MUST be supported. Existing		subtrees within the configuration datastore needs to be supported.
	mechanisms can be used to identify the subtree(s) for this purpose.
	2.8. Identifying Security Holes		2.8. Identifying Security-Sensitive Content
	One of the most important aspects of the data model documentation,		One of the most important aspects of the data model documentation,
	and biggest concerns during deployment, is the identification of		and biggest concerns during deployment, is the identification of
	security-sensitive content. This applies to operations in NETCONF,		security-sensitive content. This applies to protocol operations in
	not just data and notifications.		NETCONF, not just data and notifications.
	It is mandatory for security-sensitive objects to be documented in		It is mandatory for security-sensitive objects to be documented in
	the Security Considerations section of an RFC. This is nice, but it		the Security Considerations section of an RFC. This is nice, but it
	is not good enough, for the following reasons:		is not good enough, for the following reasons:
	o This documentation-only approach forces operators to study the RFC		o This documentation-only approach forces administrators to study
	and determine if there are any potential security holes introduced		the RFC and determine if there are any potential security risks
	by a new YANG module.		introduced by a new data model.
	o If any security holes are identified, then the operator can study		o If any security risks are identified, then the administrator can
	some more RFC text, and determine how to close the security		study some more RFC text, and determine how to mitigate the
	hole(s).		security risk(s).
	o The ACM on each server can be configured to close the security		o The ACM on each server can be configured to mitigate the security
	holes, e.g., require privileged access to read or write the		risks, e.g., require privileged access to read or write the
	specific data identified in the Security Considerations section.		specific data identified in the Security Considerations section.
	o If the ACM is not pre-configured, then there will be a time window		o If the ACM is not pre-configured, then there will be a time window
	of vulnerability, after the new module is loaded, and before the		of vulnerability, after the new data model is loaded, and before
	new access control rules for that module are configured, enabled,		the new access control rules for that data model are configured,
	and debugged.		enabled, and debugged.
	Often, the operator just wants to disable default access to the		Often, the administrator just wants to disable default access to the
	secure content, so no inadvertent or malicious changes can be made to		secure content, so no inadvertent or malicious changes can be made to
	the server. This allows the default rules to be more lenient,		the server. This allows the default rules to be more lenient,
	without significantly increasing the security risk.		without significantly increasing the security risk.
	A data model designer needs to be able to use machine-readable		A data model designer needs to be able to use machine-readable
	statements to identify NETCONF content which needs to be protected by		statements to identify NETCONF content which needs to be protected by
	default. This will allow client and server tools to automatically		default. This will allow client and server tools to automatically
	close data-model specific security holes, by denying access to		identify data-model specific security risks, by denying access to
	sensitive data unless the user is explicitly authorized to perform		sensitive data unless the user is explicitly authorized to perform
	the requested operation.		the requested access operation.
	2.9. Data Shadowing
	One of the more complicated security administration problems is
	identifying data nodes which shadow or mirror the content of another
	data node. An access control rule to prevent read operations for a
	particular node may be insufficient to prevent access to the data
	node with the copied value.
	If the description statement, other documentation, or no
	documentation exists to identify a data shadow problem, then it may
	not be detected.
	Since NETCONF allows any vendor operation to be added to the
	protocol, there is no way to reliably identify all of the operations
	that may expose copies of sensitive data nodes in <rpc-reply>
	messages.
	A NETCONF server MUST ensure that unauthorized access to its
	conceptual datastores and non-configuration data nodes is prevented.
	It is beyond the scope of this document to define access control
	enforcement procedures for underlying device instrumentation that may
	exist to support the NETCONF server operation. An operator can
	identify each operation that the server provides, and decide if it
	needs any access control applied to it.
	Proprietary protocol operations SHOULD be properly documented by the
	vendor, so it is clear to operators what data nodes (if any) are
	affected by the operation, and what information (if any) is returned
	in the <rpc-reply> message.
	2.10. NETCONF Specific Requirements
	The server MUST be able to identify the specific protocol access
	request at the 4 access control points defined above.
	The server MUST be able to identify any datastore access request,
	even for proprietary operations.
	A client MUST always be authorized to invoke the <close-session>
	operation, defined in [I-D.ietf-netconf-4741bis].
	A client MUST always be authorized to receive the <replayComplete>
	and <notificationComplete> notification events, defined in [RFC5277]
	The set of module name strings used within one particular server MUST
	be unique.
	3. NETCONF Access Control Model (NACM)		3. NETCONF Access Control Model (NACM)
	3.1. Introduction		3.1. Introduction
	This section provides a high-level overview of the access control		This section provides a high-level overview of the access control
	model structure. It describes the NETCONF protocol message		model structure. It describes the NETCONF protocol message
	processing model, and the conceptual access control requirements		processing model, and the conceptual access control requirements
	within that model.		within that model.
	skipping to change at page 14, line 31		skipping to change at page 10, line 31
	to use.		to use.
	o The concept of an emergency recovery session is supported, but		o The concept of an emergency recovery session is supported, but
	configuration of the server for this purpose is beyond the scope		configuration of the server for this purpose is beyond the scope
	of this document. An emergency recovery session will bypass all		of this document. An emergency recovery session will bypass all
	access control enforcement, in order to allow it to initialize or		access control enforcement, in order to allow it to initialize or
	repair the NACM configuration.		repair the NACM configuration.
	o A simple and familiar set of datastore permissions is used.		o A simple and familiar set of datastore permissions is used.
	o Support for YANG security tagging (e.g., nacm:secure extension)		o Support for YANG security tagging (e.g., "nacm:default-deny-write"
	allows default security modes to automatically exclude sensitive		statement) allows default security modes to automatically exclude
	data.		sensitive data.
	o Separate default access modes for read, write, and execute		o Separate default access modes for read, write, and execute
	permissions.		permissions.
	o Access control rules are applied to configurable groups of users.		o Access control rules are applied to configurable groups of users.
	o The entire ACM can be disabled during operation, in order to debug		o The entire ACM can be disabled during operation, in order to debug
	operational problems.		operational problems.
	o Access control rules are simple to configure.		o Access control rules are simple to configure.
	o The number of denied protocol operation requests and denied		o The number of denied protocol operation requests and denied
	datastore write requests can be monitored by the client.		datastore write requests can be monitored by the client.
	o Simple unconstrained YANG instance identifiers are used to		o Simple unconstrained YANG instance identifiers are used to
	configure access control rules for specific data nodes.		configure access control rules for specific data nodes.
	3.1.2. External Dependencies		3.1.2. External Dependencies
	The NETCONF [I-D.ietf-netconf-4741bis] protocol is used for all		The NETCONF [RFC6241] protocol is used for all management purposes
	management purposes within this document. It is expected that the		within this document. It is expected that the mandatory transport
	mandatory transport mapping NETCONF Over SSH		mapping NETCONF Over SSH [RFC6242] is also supported by the server,
	[I-D.ietf-netconf-rfc4742bis] is also supported by the server, and		and that the server has access to the user name associated with each
	that the server has access to the user name associated with each
	session.		session.
	The YANG Data Modeling Language [RFC6020] is used to define the		The YANG Data Modeling Language [RFC6020] is used to define the
	NETCONF data models specified in this document.		NETCONF data models specified in this document.
	3.1.3. Message Processing Model		3.1.3. Message Processing Model
	The following diagram shows the NETCONF message flow model, including		The following diagram shows the conceptual message flow model,
	the points at which access control is applied, during NETCONF message		including the points at which access control is applied, during
	processing.		NETCONF message processing.
	+-------------------------+		+-------------------------+
	| session |		| session |
	| (username) |		| (username) |
	+-------------------------+		+-------------------------+
	| ^		| ^
	V |		V |
	+--------------+ +---------------+		+--------------+ +---------------+
	| message | | message |		| message | | message |
	| dispatcher | | generator |		| dispatcher | | generator |
	+--------------+ +---------------+		+--------------+ +---------------+
	| ^ ^		| ^ ^
	V | |		V | |
	+===========+ +-------------+ +----------------+		+===========+ +-------------+ +----------------+
	| <rpc> |---> | <rpc-reply> | | <notification> |		| <rpc> |---> | <rpc-reply> | | <notification> |
	| acc. ctl | | generator | | generator |		| acc. ctl | | generator | | generator |
	+===========+ +-------------+ +----------------+		+===========+ +-------------+ +----------------+
	| ^ ^ ^		| ^ ^ ^
	V +------+ | |		V +------+ | |
	+-----------+ | +=============+ +================+		+-----------+ | +=============+ +================+
	| <rpc> | | | <rpc-reply> | | <notification> |		| <rpc> | | | read | | <notification> |
	| processor |-+ | acc. ctl | | access ctl |		| processor |-+ | data node | | access ctl |
			| | | acc. ctl | | |
	+-----------+ +=============+ +================+		+-----------+ +=============+ +================+
	| | ^ ^		| | ^ ^
	V +----------------+ | |		V +----------------+ | |
	+===========+ | | |		+===========+ | | |
			| write | | | |
	| data node | | | |		| data node | | | |
	| acc. ctl | -----------+ | | |		| acc. ctl | -----------+ | | |
	+===========+ | | | |		+===========+ | | | |
	| | | | |		| | | | |
	V V V | |		V V V | |
	+---------------+ +-----------------+		+---------------+ +-----------------+
	| configuration | ---> | server |		| configuration | ---> | server |
	| datastore | | instrumentation |		| datastore | | instrumentation |
	| | <--- | |		| | <--- | |
	+---------------+ +-----------------+		+---------------+ +-----------------+
	skipping to change at page 17, line 5		skipping to change at page 13, line 6
	Figure 2		Figure 2
	The following high-level sequence of conceptual processing steps is		The following high-level sequence of conceptual processing steps is
	executed for each received <rpc> message, if access control		executed for each received <rpc> message, if access control
	enforcement is enabled:		enforcement is enabled:
	o Access control is applied to all <rpc> messages (except <close-		o Access control is applied to all <rpc> messages (except <close-
	session>) received by the server, individually, for each active		session>) received by the server, individually, for each active
	session, unless the session is identified as a "recovery session".		session, unless the session is identified as a "recovery session".
	o If the session is authorized to execute the specified RPC		o If the user is authorized to execute the specified protocol
	operation, then processing continues, otherwise the request is		operation, then processing continues, otherwise the request is
	rejected with an "access-denied" error.		rejected with an "access-denied" error.
	o If the configuration datastore or conceptual state data is		o If the configuration datastore or conceptual state data is
	accessed by the protocol operation, then the data node access MUST		accessed by the protocol operation, then the data node access MUST
	be authorized. If the session is authorized to perform the		be authorized. If the user is authorized to perform the requested
	requested operation on the requested data, then processing		access operation on the requested data, then processing continues.
	continues.
	The following sequence of conceptual processing steps is executed for		The following sequence of conceptual processing steps is executed for
	each generated notification event, if access control enforcement is		each generated notification event, if access control enforcement is
	enabled:		enabled:
	o Server instrumentation generates a conceptual notification, for a		o Server instrumentation generates a notification, for a particular
	particular subscription.		subscription.
	o The notification access control enforcer checks the notification		o The notification access control enforcer checks the notification
	event type, and if it is one which the session is not authorized		event type, and if it is one which the user is not authorized to
	to read, then the notification is dropped for that subscription.		read, then the notification is dropped for that subscription.
	3.2. Model Components		3.2. Datastore Access
	This section defines the conceptual components related to access		The same access control rules apply to all datastores. For example,
	control model.		the candidate configuration datastore or the running configuration
			datastore.
	3.2.1. Users		Only the standard NETCONF datastores (candidate, running, and
			startup) are controlled by the ACM. Local or remote files or
			datastores accessed via the <url> parameter are optional to support.
	A "user" is the conceptual entity that is associated with the access		3.2.1. Access Rights
	permissions granted to a particular session. A user is identified by
	a string which MUST be unique within the server.
	As described in [I-D.ietf-netconf-4741bis], the user name string is		A small set of hard-wired datastore access rights is needed to
	derived from the transport layer during session establishment. If		control access to all possible NETCONF protocol operations, including
	the transport layer cannot authenticate the user, the session is		vendor extensions to the standard protocol operation set.
	terminated.
	The server MAY support a "recovery session" mechanism, which will		The "CRUDX" model can support all NETCONF protocol operations:
	bypass all access control enforcement. This is useful for
	restricting initial access and repairing a broken access control
	configuration.
	3.2.2. Groups		o Create: Allows the client to add a new data node instance to a
			datastore.
	Access to a specific NETCONF operation is granted to a session,		o Read: Allows the client to read a data node instance from a
	associated with a group, not a user.		datastore, or receive the notification event type.
	A group is identified by its name. All group names MUST be unique		o Update: Allows the client to update an existing data node instance
	within the server.		in a datastore.
	A group member is identified by a user name string.		o Delete: Allows the client to delete a data node instance from a
			datastore.
	The same user may be configured in multiple groups.		o eXec: Allows the client to execute the protocol operation.
	3.2.3. Sessions		3.2.2. <get> and <get-config> Operations
	A session is simply a NETCONF session, which is the entity that is		Data nodes to which the client does not have read access are silently
	granted access to specific NETCONF operations.		omitted from the <rpc-reply> message. This is done to allow NETCONF
			filters for <get> and <get-config> to function properly, instead of
			causing an "access-denied" error because the filter criteria would
			otherwise include unauthorized read access to some data nodes. For
			NETCONF filtering purposes, the selection criteria is applied to the
			subset of nodes that the user is authorized to read, not the entire
			datastore.
	A session is associated with a single user name for the lifetime of		3.2.3. <edit-config> Operation
	the session.
	3.2.4. Access Permissions		The NACM access rights are not directly coupled to the <edit-config>
			"operation" attribute, although they are similar. Instead, a NACM
			access right applies to all protocol operations which would result in
			a particular access operation to the target datastore. This section
			describes how these access rights apply to the specific access
			operations supported by the <edit-config> protocol operation.
	The access permissions are the NETCONF protocol specific set of		If the effective access operation is "none" (i.e., default-
	permissions that have been assigned to a particular session.		operation="none") for a particular data node, then no access control
			is applied to that data node.
	The same access permissions MUST stay in effect for the processing of		If the protocol operation would result in the creation of a data
	a particular message.		store node, and the user does not have "create" access permission for
			that node, the protocol operation is rejected with an "access-denied"
			error.
	The server MUST use the access control rules in effect at the time		If the protocol operation would result in the deletion of a data
	the message is processed.		store node, and the user does not have "delete" access permission for
			that node, the protocol operation is rejected with an "access-denied"
			error.
	The access control model treats protocol operation execution		If the protocol operation would result in the modification of a data
	separately from configuration datastore access and outgoing messages:		store node, and the user does not have "update" access permission for
			that node, the protocol operation is rejected with an "access-denied"
			error.
	create: Permission to create conceptual server data.		A "merge" or "replace" <edit-config> operation may include data nodes
			which do not alter portions of the existing datastore. For example,
			a container or list node may be present for naming purposes, but does
			not actually alter the corresponding datastore node. These unaltered
			data nodes are ignored by the server, and do not require any access
			rights by the client.
	read: Read access to conceptual server data, <rpc-reply> and		A "merge" <edit-config> operation may include data nodes, but not
	<notification> content.		include particular child data nodes that are present in the
			datastore. These missing data nodes within the scope of a "merge"
			<edit-config> operation are ignored by the server, and do not require
			any access rights by the client.
	update: Permission to modify existing conceptual server data.		The contents of specific restricted datastore nodes MUST NOT be
			exposed in any <rpc-error> elements within the reply.
	delete: Permission to delete existing conceptual server data.		3.2.4. <copy-config> Operation
	exec: Permission to invoke a protocol operation.		Access control for the <copy-config> protocol operation requires
			special consideration because the administrator may be replacing the
			entire target datastore.
	3.2.5. Global Enforcement Controls		If the source of the <copy-config> protocol operation is the running
			configuration datastore, and the target is the startup configuration
			datastore, the client is only required to have permission to execute
			the <copy-config> protocol operation.
			Otherwise:
			o If the source of the <copy-config> operation is a datastore, then
			data nodes to which the client does not have read access are
			silently omitted.
			o If the target of the <copy-config> operation is a datastore, the
			client needs access to the modified nodes. Specifically:
			If the protocol operation would result in the creation of a
			data store node, and the user does not have "create" access
			permission for that node, the protocol operation is rejected
			with an "access-denied" error.
			If the protocol operation would result in the deletion of a
			data store node, and the user does not have "delete" access
			permission for that node, the protocol operation is rejected
			with an "access-denied" error.
			If the protocol operation would result in the modification of a
			data store node, and the user does not have "update" access
			permission for that node, the protocol operation is rejected
			with an "access-denied" error.
			3.2.5. <delete-config> Operation
			Access to the <delete-config> protocol operation is denied by
			default. The 'exec-default' parameter does not apply to this
			protocol operation. Access control rules must be explicitly
			configured to allow invocation by a non-recovery session.
			3.2.6. <commit> Operation
			The server MUST determine the exact nodes in the running
			configuration datastore which are actually different, and only check
			"create", "update", and "delete" access permissions for this set of
			nodes, which could be empty.
			For example, if a session can read the entire datastore, but only
			change one leaf, that session needs to be able to edit and commit
			that one leaf.
			3.2.7. <discard-changes> Operation
			The client is only required to have permission to execute the
			<discard-changes> protocol operation. No datastore permissions are
			needed.
			3.2.8. <kill-session> Operation
			The <kill-session> operation does not directly alter a datastore.
			However, it allows one session to disrupt another session which is
			editing a datastore.
			Access to the <kill-session> protocol operation is denied by default.
			The 'exec-default' parameter does not apply to this protocol
			operation. Access control rules must be explicitly configured to
			allow invocation by a non-recovery session.
			3.3. Model Components
			This section defines the conceptual components related to access
			control model.
			3.3.1. Users
			A "user" is the conceptual entity that is associated with the access
			permissions granted to a particular session. A user is identified by
			a string which is unique within the server.
			As described in [RFC6241], the user name string is derived from the
			transport layer during session establishment. If the transport layer
			cannot authenticate the user, the session is terminated.
			The server MAY support a "recovery session" mechanism, which will
			bypass all access control enforcement. This is useful for
			restricting initial access and repairing a broken access control
			configuration.
			3.3.2. Groups
			Access to a specific NETCONF protocol operation is granted to a
			session, associated with a group, not a user.
			A group is identified by its name. All group names are unique within
			the server.
			A group member is identified by a user name string.
			The same user can be a member of multiple groups.
			3.3.3. Global Enforcement Controls
	There are four global controls that are used to help control how		There are four global controls that are used to help control how
	access control is enforced.		access control is enforced.
	3.2.5.1. enable-nacm Switch		3.3.3.1. enable-nacm Switch
	A global "enable-nacm" on/off switch is provided to enable or disable		A global "enable-nacm" on/off switch is provided to enable or disable
	all access control enforcement. When this global switch is set to		all access control enforcement. When this global switch is set to
	"true", then all access requested are checked against the access		"true", then all requests are checked against the access control
	control rules, and only permitted if configured to allow the specific		rules, and only permitted if configured to allow the specific access
	access request. When this global switch is set to "false", then all		request. When this global switch is set to "false", then all access
	access requested are permitted.		requested are permitted.
	3.2.5.2. read-default Switch		3.3.3.2. read-default Switch
	An on/off "read-default" switch is provided to enable or disable		An on/off "read-default" switch is provided to enable or disable
	default access to receive data in replies and notifications. When		default access to receive data in replies and notifications. When
	the "enable-nacm" global switch is set to "true", then this global		the "enable-nacm" global switch is set to "true", then this global
	switch is relevant, if no matching access control rule is found to		switch is relevant, if no matching access control rule is found to
	explicitly permit or deny read access to the requested NETCONF		explicitly permit or deny read access to the requested NETCONF
	datastore data or notification event type.		datastore data or notification event type.
	When this global switch is set to "permit", and no matching access		When this global switch is set to "permit", and no matching access
	control rule is found for the NETCONF datastore read or notification		control rule is found for the NETCONF datastore read or notification
	event requested, then access is permitted.		event requested, then access is permitted.
	When this global switch is set to "deny", and no matching access		When this global switch is set to "deny", and no matching access
	control rule is found for the NETCONF datastore read or notification		control rule is found for the NETCONF datastore read or notification
	event requested, then access is denied.		event requested, then access is denied.
	3.2.5.3. write-default Switch		3.3.3.3. write-default Switch
	An on/off "write-default" switch is provided to enable or disable		An on/off "write-default" switch is provided to enable or disable
	default access to alter configuration data. When the "enable-nacm"		default access to alter configuration data. When the "enable-nacm"
	global switch is set to "true", then this global switch is relevant,		global switch is set to "true", then this global switch is relevant,
	if no matching access control rule is found to explicitly permit or		if no matching access control rule is found to explicitly permit or
	deny write access to the requested NETCONF datastore data.		deny write access to the requested NETCONF datastore data.
	When this global switch is set to "permit", and no matching access		When this global switch is set to "permit", and no matching access
	control rule is found for the NETCONF datastore write requested, then		control rule is found for the NETCONF datastore write requested, then
	access is permitted.		access is permitted.
	When this global switch is set to "deny", and no matching access		When this global switch is set to "deny", and no matching access
	control rule is found for the NETCONF datastore write requested, then		control rule is found for the NETCONF datastore write requested, then
	access is denied.		access is denied.
	3.2.5.4. exec-default Switch		3.3.3.4. exec-default Switch
	An on/off "exec-default" switch is provided to enable or disable		An on/off "exec-default" switch is provided to enable or disable
	default access to execute protocol operations. When the "enable-		default access to execute protocol operations. When the "enable-
	nacm" global switch is set to "true", then this global switch is		nacm" global switch is set to "true", then this global switch is
	relevant, if no matching access control rule is found to explicitly		relevant, if no matching access control rule is found to explicitly
	permit or deny access to the requested NETCONF protocol operation.		permit or deny access to the requested NETCONF protocol operation.
	When this global switch is set to "permit", and no matching access		When this global switch is set to "permit", and no matching access
	control rule is found for the NETCONF protocol operation requested,		control rule is found for the NETCONF protocol operation requested,
	then access is permitted.		then access is permitted.
	When this global switch is set to "deny", and no matching access		When this global switch is set to "deny", and no matching access
	control rule is found for the NETCONF protocol operation requested,		control rule is found for the NETCONF protocol operation requested,
	then access is denied.		then access is denied.
	3.2.6. Access Control Rules		3.3.4. Access Control Rules
	There are 4 types of rules available in NACM:		There are 4 types of rules available in NACM:
	module rule: Controls access for definitions in a specific module,		module rule: Controls access for definitions in a specific YANG
	identified by its name.		module, identified by its name.
	protocol operation rule: Controls access for a specific protocol		protocol operation rule: Controls access for a specific protocol
	operation, identified by its module and name.		operation, identified by its YANG module and name.
	data node rule: Controls access for a specific data node, identified		data node rule: Controls access for a specific data node, identified
	by its path location within the conceptual XML document for the		by its path location within the conceptual XML document for the
	data node.		data node.
	notification rule: Controls access for a specific notification event		notification rule: Controls access for a specific notification event
	type, identified by its module and name.		type, identified by its YANG module and name.
	3.3. Access Control Enforcement Procedures		3.4. Access Control Enforcement Procedures
	There are seven separate phases that need to be addressed, four of		There are seven separate phases that need to be addressed, four of
	which are related to the NETCONF message processing model. In		which are related to the NETCONF message processing model. In
	addition, the initial start-up mode for a NETCONF server, session		addition, the initial start-up mode for a NETCONF server, session
	establishment, and "access-denied" error handling procedures also		establishment, and "access-denied" error handling procedures also
	need to be considered.		need to be considered.
	3.3.1. Initial Operation		The server MUST use the access control rules in effect at the time it
			starts processing the message. The same access control rules MUST
			stay in effect for the processing of the entire message.
			3.4.1. Initial Operation
	Upon the very first start-up of the NETCONF server, the access		Upon the very first start-up of the NETCONF server, the access
	control configuration will probably not be present. If it isn't, a		control configuration will probably not be present. If it isn't, a
	server MUST NOT allow any write access to any session role except a		server MUST NOT allow any write access to any session role except a
	"recovery session", if supported.		"recovery session".
	Access control rules are not enforced before or while the non-		Access rules are enforced any time a request is initiated from a user
	volatile configuration data is processed and loaded into the running		session. Access control is not enforced for server-initiated access
	configuration, when the server is booting or rebooting. Access rules		requests, such as the initial load of the running datastore, during
	are enforced any time a request is initiated from a user session.		bootup.
	Access control is not enforced for server-initiated access requests,
	such as the initial load of the running datastore, during bootup.
	3.3.2. Session Establishment		3.4.2. Session Establishment
	The access control model applies specifically to the well-formed XML		The access control model applies specifically to the well-formed XML
	content transferred between a client and a server, after session		content transferred between a client and a server, after session
	establishment has been completed, and after the <hello> exchange has		establishment has been completed, and after the <hello> exchange has
	been successfully completed.		been successfully completed.
	A server SHOULD NOT include any sensitive information in any
	<capability> elements within the <hello> exchange.
	Once session establishment is completed, and a user has been		Once session establishment is completed, and a user has been
	authenticated, the NETCONF transport layer reports the user name and		authenticated, the NETCONF transport layer reports the user name and
	a possibly empty set of group names associated with the user to the		a possibly empty set of group names associated with the user to the
	NETCONF server. The NETCONF server will enforce the access control		NETCONF server. The NETCONF server will enforce the access control
	rules, based on the supplied user name, group names, and the		rules, based on the supplied user name, group names, and the
	configuration data stored on the server.		configuration data stored on the server.
	3.3.3. "access-denied" Error Handling		3.4.3. "access-denied" Error Handling
	The "access-denied" error-tag is generated when the access control		The "access-denied" error-tag is generated when the access control
	system denies access to either a request to invoke a protocol		system denies access to either a request to invoke a protocol
	operation or a request to perform a particular operation on the		operation or a request to perform a particular access operation on
	configuration datastore.		the configuration datastore.
	A server MUST NOT include any sensitive information in any <error-		A server MUST NOT include any sensitive information in any <error-
	info> elements within the <rpc-error> response.		info> elements within the <rpc-error> response.
	3.3.4. Incoming RPC Message Validation		3.4.4. Incoming RPC Message Validation
	The diagram below shows the basic conceptual structure of the access		The diagram below shows the basic conceptual structure of the access
	control processing model for incoming NETCONF <rpc> messages, within		control processing model for incoming NETCONF <rpc> messages, within
	a server.		a server.
	NETCONF server		NETCONF server
	+------------+		+------------+
	| XML |		| XML |
	| message |		| message |
	| dispatcher |		| dispatcher |
	skipping to change at page 22, line 41		skipping to change at page 21, line 7
	| configuration |		| configuration |
	| datastore |		| datastore |
	+----------------------+		+----------------------+
	Figure 3		Figure 3
	Access control begins with the message dispatcher.		Access control begins with the message dispatcher.
	After the server validates the <rpc> element, and determines the		After the server validates the <rpc> element, and determines the
	namespace URI and the element name of the protocol operation being		namespace URI and the element name of the protocol operation being
	requested, the RPC access control enforcer verifies that the session		requested, the server verifies that the user is authorized to invoke
	is authorized to invoke the protocol operation.		the protocol operation.
	The protocol operation is authorized by following these steps:		The protocol operation is authorized by following these steps:
	1. If the "enable-nacm" leaf is set to "false", then the protocol		1. If the "enable-nacm" leaf is set to "false", then the protocol
	operation is permitted.		operation is permitted.
	2. If the requesting session is identified as a "recovery session",		2. If the requesting session is identified as a "recovery session",
	then the protocol operation is permitted.		then the protocol operation is permitted.
	3. If the requested operation is the NETCONF <close-session>		3. If the requested operation is the NETCONF <close-session>
	operation, then the protocol operation is permitted.		protocol operation, then the protocol operation is permitted.
	4. Check all the "group" entries for ones that contain a "user-		4. Check all the "group" entries for ones that contain a "user-
	name" entry that equals the user name for the session making the		name" entry that equals the user name for the session making the
	request. Add to these groups the set of groups provided by the		request. Add to these groups the set of groups provided by the
	transport layer.		transport layer.
	5. If no groups are found, continue with step 10.		5. If no groups are found, continue with step 10.
	6. Process all rule-list entries, in order. If a rule-list's		6. Process all rule-list entries, in the order they appear in the
	"group" leaf-list does not match any of the user's groups,		configuration. If a rule-list's "group" leaf-list does not
	proceed to the next rule-list entry.		match any of the user's groups, proceed to the next rule-list
			entry.
	7. For each rule-list entry found, process all rules, in order,		7. For each rule-list entry found, process all rules, in order,
	until a rule that matches the requested operation is found. A		until a rule that matches the requested access operation is
	rule matches if all of the following criteria are met:		found. A rule matches if all of the following criteria are met:
	* The rule's "module-name" leaf is "*", or equals the name of		* The rule's "module-name" leaf is "*", or equals the name of
	the YANG module where the protocol operation is defined.		the YANG module where the protocol operation is defined.
	* The rule does not have a "rule-type" defined, or the "rule-		* The rule does not have a "rule-type" defined, or the "rule-
	type" is "protocol-operation" and the "rpc-name" is "*" or		type" is "protocol-operation" and the "rpc-name" is "*" or
	equals the name of the requested protocol operation.		equals the name of the requested protocol operation.
	* The rule's "access-operations" leaf has the "exec" bit set,		* The rule's "access-operations" leaf has the "exec" bit set,
	or has the special value "*".		or has the special value "*".
	8. If a matching rule is found, then the "action" leaf is checked.		8. If a matching rule is found, then the "action" leaf is checked.
	If it is equal to "permit", then the protocol operation is		If it is equal to "permit", then the protocol operation is
	permitted, otherwise it is denied.		permitted, otherwise it is denied.
	9. Otherwise, no matching rule was found in any rule-list entry.		9. Otherwise, no matching rule was found in any rule-list entry.
	10. If the requested protocol operation is defined in a YANG module		10. If the requested protocol operation is defined in a YANG module
	advertised in the server capabilities, and the "rpc" statement		advertised in the server capabilities, and the "rpc" statement
	contains a "nacm:secure" or a "nacm:very-secure" statement, then		contains a "nacm:default-deny-all" statement, then the protocol
	the protocol operation is denied.		operation is denied.
	11. If the "exec-default" leaf is set to "permit", then permit the		11. If the requested protocol operation is the NETCONF <kill-
			session> or <delete-config>, then the protocol operation is
			denied.
			12. If the "exec-default" leaf is set to "permit", then permit the
	protocol operation, otherwise deny the request.		protocol operation, otherwise deny the request.
	If the session is not authorized to invoke the protocol operation		If the user is not authorized to invoke the protocol operation then
	then an <rpc-error> is generated with the following information:		an <rpc-error> is generated with the following information:
	error-tag: access-denied		error-tag: access-denied
	error-path: Identifies the requested protocol operation. For		error-path: Identifies the requested protocol operation. For
	example:		example:
	<error-path		<error-path
	xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">		xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
	/nc:rpc/nc:edit-config		/nc:rpc/nc:edit-config
	</error-path>		</error-path>
	represents the <edit-config> operation in the NETCONF base		represents the <edit-config> protocol operation in the NETCONF
	namespace.		base namespace.
	If a datastore is accessed, either directly or as a side effect of		If a datastore is accessed, either directly or as a side effect of
	the protocol operation, then the server MUST intercept the operation		the protocol operation, then the server MUST intercept the access
	and make sure the session is authorized to perform the requested		operation and make sure the user is authorized to perform the
	operation on the specified data, as defined in Section 3.3.5.		requested access operation on the specified data, as defined in
			Section 3.4.5.
	3.3.5. Data Node Access Validation		3.4.5. Data Node Access Validation
	If a data node within a datastore is accessed, then the server MUST		If a data node within a datastore is accessed, then the server MUST
	ensure that the client session is authorized to perform the requested		ensure that the user is authorized to perform the requested read,
	read, create, update, or delete operation on the specified data node.		create, update, or delete access operation on the specified data
			node.
	The data node access request is authorized by following these steps:		The data node access request is authorized by following these steps:
	1. If the "enable-nacm" leaf is set to "false", then the protocol		1. If the "enable-nacm" leaf is set to "false", then the access
	operation is permitted.		operation is permitted.
	2. If the requesting session is identified as a "recovery session",		2. If the requesting session is identified as a "recovery session",
	then the protocol operation is permitted.		then the access operation is permitted.
	3. Check all the "group" entries for ones that contain a "user-		3. Check all the "group" entries for ones that contain a "user-
	name" entry that equals the user name for the session making the		name" entry that equals the user name for the session making the
	request. Add to these groups the set of groups provided by the		request. Add to these groups the set of groups provided by the
	transport layer.		transport layer.
	4. If no groups are found, continue with step 9.		4. If no groups are found, continue with step 9.
	5. Process all rule-list entries, in order. If a rule-list's		5. Process all rule-list entries, in the order they appear in the
	"group" leaf-list does not match any of the user's groups,		configuration. If a rule-list's "group" leaf-list does not
	proceed to the next rule-list entry.		match any of the user's groups, proceed to the next rule-list
			entry.
	6. For each rule-list entry found, process all rules, in order,		6. For each rule-list entry found, process all rules, in order,
	until a rule that matches the requested operation is found. A		until a rule that matches the requested access operation is
	rule matches if all of the following criteria are met:		found. A rule matches if all of the following criteria are met:
	* The rule's "module-name" leaf is "*", or equals the name of		* The rule's "module-name" leaf is "*", or equals the name of
	the YANG module where the protocol operation is defined.		the YANG module where the requested data node is defined.
	* The rule does not have a "rule-type" defined, or the "rule-		* The rule does not have a "rule-type" defined, or the "rule-
	type" is "data-node" and the "path" matches the requested		type" is "data-node" and the "path" matches the requested
	data node.		data node.
	* For a read operation, the rule's "access-operations" leaf has		* For a read access operation, the rule's "access-operations"
	the "read" bit set, or has the special value "*".		leaf has the "read" bit set, or has the special value "*".
	* For a creation operation, the rule's "access-operations" leaf		* For a create access operation, the rule's "access-operations"
	has the "create" bit set, or has the special value "*".		leaf has the "create" bit set, or has the special value "*".
	* For a deletion operation, the rule's "access-operations" leaf		* For a delete access operation, the rule's "access-operations"
	has the "delete" bit set, or has the special value "*".		leaf has the "delete" bit set, or has the special value "*".
	* For an update operation, the rule's "access-operations" leaf		* For an update access operation, the rule's "access-
	has the "update" bit set, or has the special value "*".		operations" leaf has the "update" bit set, or has the special
			value "*".
	7. If a matching rule is found, then the "action" leaf is checked.		7. If a matching rule is found, then the "action" leaf is checked.
	If it is equal to "permit", then the data node access is		If it is equal to "permit", then the data node access is
	permitted, otherwise it is denied. For a read operation,		permitted, otherwise it is denied. For a read access operation,
	"denied" means that the requested data is not returned in the		"denied" means that the requested data is not returned in the
	reply.		reply.
	8. Otherwise, no matching rule was found in any rule-list entry.		8. Otherwise, no matching rule was found in any rule-list entry.
	9. For a read operation, if the requested data node is defined in a		9. For a read access operation, if the requested data node is
	YANG module advertised in the server capabilities, and the data		defined in a YANG module advertised in the server capabilities,
	definition statement contains a "nacm:very-secure" statement,		and the data definition statement contains a "nacm:default-deny-
	then the requested data node is not included in the reply.		all" statement, then the requested data node is not included in
			the reply.
	10. For a write operation, if the requested data node is defined in		10. For a write access operation, if the requested data node is
	a YANG module advertised in the server capabilities, and the		defined in a YANG module advertised in the server capabilities,
	data definition statement contains a "nacm:secure" or a "nacm:		and the data definition statement contains a "nacm:default-deny-
	very-secure" statement, then the data node access request is		write" or a "nacm:default-deny-all" statement, then the data
	denied.		node access request is denied.
	11. For a read operation, if the "read-default" leaf is set to		11. For a read access operation, if the "read-default" leaf is set
	"permit", then include the requested data node in the reply,		to "permit", then include the requested data node in the reply,
	otherwise do not include the requested data node in the reply.		otherwise do not include the requested data node in the reply.
	12. For a write operation, if the "write-default" leaf is set to		12. For a write access operation, if the "write-default" leaf is set
	"permit", then permit the data node access request, otherwise		to "permit", then permit the data node access request, otherwise
	deny the request.		deny the request.
	3.3.6. Outgoing <notification> Authorization		3.4.6. Outgoing <notification> Authorization
	Configuration of access control rules specifically for descendant		Configuration of access control rules specifically for descendant
	nodes of the notification event type element are outside the scope of		nodes of the notification event type element are outside the scope of
	this document. If the session is authorized to receive the		this document. If the user is authorized to receive the notification
	notification event type, then it is also authorized to receive any		event type, then it is also authorized to receive any data it
	data it contains.		contains.
	The following figure shows the conceptual message processing model		The following figure shows the conceptual message processing model
	for outgoing <notification> messages.		for outgoing <notification> messages.
	NETCONF server		NETCONF server
	+------------+		+------------+
	| XML |		| XML |
	| message |		| message |
	| generator |		| generator |
	+------------+		+------------+
	skipping to change at page 27, line 15		skipping to change at page 25, line 48
	The generation of a notification for a specific subscription is		The generation of a notification for a specific subscription is
	authorized by following these steps:		authorized by following these steps:
	1. If the "enable-nacm" leaf is set to "false", then the		1. If the "enable-nacm" leaf is set to "false", then the
	notification is permitted.		notification is permitted.
	2. If the session is identified as a "recovery session", then the		2. If the session is identified as a "recovery session", then the
	notification is permitted.		notification is permitted.
	3. If the notification is the NETCONF <replayComplete> or		3. If the notification is the NETCONF <replayComplete> or
	<notificationComplete> event type, then the notification is		<notificationComplete> event type [RFC5277], then the
	permitted.		notification is permitted.
	4. Check all the "group" entries for ones that contain a "user-		4. Check all the "group" entries for ones that contain a "user-
	name" entry that equals the user name for the session making the		name" entry that equals the user name for the session making the
	request. Add to these groups the set of groups provided by the		request. Add to these groups the set of groups provided by the
	transport layer.		transport layer.
	5. If no groups are found, continue with step 10.		5. If no groups are found, continue with step 10.
	6. Process all rule-list entries, in order. If a rule-list's		6. Process all rule-list entries, in the order they appear in the
	"group" leaf-list does not match any of the user's groups,		configuration. If a rule-list's "group" leaf-list does not
	proceed to the next rule-list entry.		match any of the user's groups, proceed to the next rule-list
			entry.
	7. For each rule-list entry found, process all rules, in order,		7. For each rule-list entry found, process all rules, in order,
	until a rule that matches the requested operation is found. A		until a rule that matches the requested access operation is
	rule matches if all of the following criteria are met:		found. A rule matches if all of the following criteria are met:
	* The rule's "module-name" leaf is "*", or equals the name of		* The rule's "module-name" leaf is "*", or equals the name of
	the YANG module where the protocol operation is defined.		the YANG module where the notification is defined.
	* The rule does not have a "rule-type" defined, or the "rule-		* The rule does not have a "rule-type" defined, or the "rule-
	type" is "notification" and the "notification-name" is "*",		type" is "notification" and the "notification-name" is "*",
	equals the name of the notification.		equals the name of the notification.
	* The rule's "access-operations" leaf has the "read" bit set,		* The rule's "access-operations" leaf has the "read" bit set,
	or has the special value "*".		or has the special value "*".
	8. If a matching rule is found, then the "action" leaf is checked.		8. If a matching rule is found, then the "action" leaf is checked.
	If it is equal to "permit", then permit the notification,		If it is equal to "permit", then permit the notification,
	otherwise drop the notification for the associated subscription.		otherwise drop the notification for the associated subscription.
	9. Otherwise, no matching rule was found in any rule-list entry.		9. Otherwise, no matching rule was found in any rule-list entry.
	10. If the requested notification is defined in a YANG module		10. If the requested notification is defined in a YANG module
	advertised in the server capabilities, and the "notification"		advertised in the server capabilities, and the "notification"
	statement contains a "nacm:very-secure" statement, then the		statement contains a "nacm:default-deny-all" statement, then the
	notification is dropped for the associated subscription.		notification is dropped for the associated subscription.
	11. If the "read-default" leaf is set to "permit", then permit the		11. If the "read-default" leaf is set to "permit", then permit the
	notification, otherwise drop the notification for the associated		notification, otherwise drop the notification for the associated
	subscription.		subscription.
	3.4. Data Model Definitions		3.5. Data Model Definitions
	This section defines the semantics of the conceptual data structures		This section defines the semantics of the conceptual data structures
	found in the data model in Section 3.4.		found in the data model in Section 3.5.
	3.4.1. Data Organization
	The top-level element is called <nacm>, and it is defined in the
	"ietf-netconf-acm" module's namespace.
	There are several data structures defined as child nodes of the
	<nacm> element:
	leaf <enable-nacm>: On/off boolean switch to enable or disable
	access control enforcement.
	leaf <read-default>: Enumeration to permit or deny default read
	access requests.
	leaf <write-default>: Enumeration to permit or deny default write
	access requests.
	leaf <exec-default>: Enumeration to permit or deny default protocol
	operation execution requests.
	leaf <denied-rpcs>: Read-only counter of the number of times the
	server has denied an RPC operation request, since the last reboot
	of the server.
	leaf <denied-data-writes>: Read-only counter of the number of times
	the server has denied a data node write request, since the last
	reboot of the server.
	leaf <denied-notifications>: Read-only counter of the number of
	times the server has denied a notification, since the last reboot
	of the server.
	container <groups>: Configures the groups used within the access
	control system.
	list <group>: A list of user names belonging to the same
	administrative group.
	container <rules>: Configures the access control rules used within		3.5.1. Data Organization
	the server.
	list <rule-list>: An ordered collection of related access control		The following diagram highlights the contents and structure of the
	rules.		NACM YANG module.
	list <rule>: Configures the access control rules for protocol		+--rw nacm
	operation invocation, configuration datastore access, and		+--rw enable-nacm? boolean
	for controlling delivery of <notification> events.		+--rw read-default? action-type
			+--rw write-default? action-type
			+--rw exec-default? action-type
			+--ro denied-operations yang:zero-based-counter32
			+--ro denied-data-writes yang:zero-based-counter32
			+--ro denied-notifications yang:zero-based-counter32
			+--rw groups
			| +--rw group [name]
			| +--rw name group-name-type
			| +--rw user-name* user-name-type
			+--rw rule-list [name]
			+--rw name string
			+--rw group* union
			+--rw rule [name]
			+--rw name string
			+--rw module-name? union
			+--rw (rule-type)?
			| +--:(protocol-operation)
			| | +--rw rpc-name? union
			| +--:(notification)
			| | +--rw notification-name? union
			| +--:(data-node)
			| +--rw path node-instance-identifier
			+--rw access-operations? union
			+--rw action action-type
			+--rw comment? string
	3.4.2. YANG Module		3.5.2. YANG Module
	The following YANG module specifies the normative NETCONF content		The following YANG module specifies the normative NETCONF content
	that MUST by supported by the server.		that MUST by supported by the server.
	The ietf-netconf-acm YANG module imports typedefs from [RFC6021].		The "ietf-netconf-acm" YANG module imports typedefs from [RFC6021].
	// RFC Ed.: please update the date to the date of publication
	<CODE BEGINS> file="ietf-netconf-acm@2011-06-14.yang"
	module ietf-netconf-acm {
	namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-acm";
	prefix "nacm";
	import ietf-yang-types {
	prefix yang;
	}
	organization
	"IETF NETCONF (Network Configuration) Working Group";
	contact		// RFC Ed.: please update the date to the date of publication
	"WG Web: <http://tools.ietf.org/wg/netconf/>		<CODE BEGINS> file="ietf-netconf-acm@2011-10-04.yang"
	WG List: <mailto:netconf@ietf.org>
	WG Chair: Mehmet Ersue		module ietf-netconf-acm {
	<mailto:mehmet.ersue@nsn.com>
	WG Chair: Bert Wijnen		namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-acm";
	<mailto:bertietf@bwijnen.net>		prefix "nacm";
	Editor: Andy Bierman		import ietf-yang-types {
	<mailto:andy.bierman@brocade.com>		prefix yang;
			}
	Editor: Martin Bjorklund		organization
	<mailto:mbj@tail-f.com>";		"IETF NETCONF (Network Configuration) Working Group";
	description		contact
	"NETCONF Server Access Control Model.		"WG Web: <http://tools.ietf.org/wg/netconf/>
			WG List: <mailto:netconf@ietf.org>
	Copyright (c) 2011 IETF Trust and the persons identified as		WG Chair: Mehmet Ersue
	authors of the code. All rights reserved.		<mailto:mehmet.ersue@nsn.com>
	Redistribution and use in source and binary forms, with or		WG Chair: Bert Wijnen
	without modification, is permitted pursuant to, and subject		<mailto:bertietf@bwijnen.net>
	to the license terms contained in, the Simplified BSD
	License set forth in Section 4.c of the IETF Trust's
	Legal Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info).
	This version of this YANG module is part of RFC XXXX; see		Editor: Andy Bierman
	the RFC itself for full legal notices.";		<mailto:andy.bierman@brocade.com>
	// RFC Ed.: replace XXXX with actual RFC number and
	// remove this note
	// RFC Ed.: remove this note		Editor: Martin Bjorklund
	// Note: extracted from draft-ietf-netconf-access-control-04.txt		<mailto:mbj@tail-f.com>";
	// RFC Ed.: please update the date to the date of publication
	revision "2011-06-14" {
	description		description
	"Initial version";		"NETCONF Access Control Model.
	reference
	"RFC XXXX: Network Configuration Protocol
	Access Control Model";
	}
	/*		Copyright (c) 2011 IETF Trust and the persons identified as
	* Extension statements		authors of the code. All rights reserved.
	*/
	extension secure {		Redistribution and use in source and binary forms, with or
	description		without modification, is permitted pursuant to, and subject
	"Used to indicate that the data model node		to the license terms contained in, the Simplified BSD
	represents a sensitive security system parameter.		License set forth in Section 4.c of the IETF Trust's
			Legal Provisions Relating to IETF Documents
			(http://trustee.ietf.org/license-info).
	If present, and the NACM module is enabled (i.e.,		This version of this YANG module is part of RFC XXXX; see
	/nacm/enable-nacm object equals 'true'), the NETCONF server		the RFC itself for full legal notices.";
	will only allow the designated 'recovery session' to have		// RFC Ed.: replace XXXX with actual RFC number and
	write or execute access to the node. An explicit access		// remove this note
	control rule is required for all other users.
	The 'secure' extension MAY appear within a data definition		// RFC Ed.: remove this note
	statement or rpc statement. It is ignored otherwise.";		// Note: extracted from draft-ietf-netconf-access-control-05.txt
	}
	extension very-secure {		// RFC Ed.: please update the date to the date of publication
	description		revision "2011-10-04" {
	"Used to indicate that the data model node		description
	controls a very sensitive security system parameter.		"Initial version";
			reference
			"RFC XXXX: Network Configuration Protocol
			Access Control Model";
			}
	If present, and the NACM module is enabled (i.e.,		/*
	/nacm/enable-nacm object equals 'true'), the NETCONF server		* Extension statements
	will only allow the designated 'recovery session' to have		*/
	read, write, or execute access to the node. An explicit
	access control rule is required for all other users.
	The 'very-secure' extension MAY appear within a data		extension default-deny-write {
	definition statement, rpc statement, or notification		description
	statement. It is ignored otherwise.";		"Used to indicate that the data model node
	}		represents a sensitive security system parameter.
	/*		If present, and the NACM module is enabled (i.e.,
	* Derived types		/nacm/enable-nacm object equals 'true'), the NETCONF server
	*/		will only allow the designated 'recovery session' to have
			write access to the node. An explicit access control rule is
			required for all other users.
	typedef user-name-type {		The 'default-deny-write' extension MAY appear within a data
	type string {		definition statement. It is ignored otherwise.";
	length "1..max";
	}		}
	description
	"General Purpose User Name string.";
	}
	typedef matchall-string-type {		extension default-deny-all {
	type string {		description
	pattern "\*";		"Used to indicate that the data model node
	}		controls a very sensitive security system parameter.
	description
	"The string containing a single asterisk '*' is used
	to conceptually represent all possible values
	for the particular leaf using this data type.";
	}
	typedef access-operations-type {		If present, and the NACM module is enabled (i.e.,
	type bits {		/nacm/enable-nacm object equals 'true'), the NETCONF server
	bit create {		will only allow the designated 'recovery session' to have
	description		read, write, or execute access to the node. An explicit
	"Any operation that creates a		access control rule is required for all other users.
	new instance of the specified data is a create
	operation.";
	}
	bit read {
	description
	"Any operation or notification that
	returns data to an application is a read
	operation.";
	}
	bit update {
	description
	"Any operation that alters an existing
	data node is an update operation.";
	}
	bit delete {
	description
	"Any operation that removes a datastore
	node instance is a delete operation.";
	}
	bit exec {
	description
	"Execution access to the specified RPC operation.
	Any RPC operation invocation is an exec operation.";
	}
	}
	description
	"NETCONF Access Operation.";
	}
	typedef group-name-type {		The 'default-deny-all' extension MAY appear within a data
	type string {		definition statement, 'rpc' statement, or 'notification'
	length "1..max";		statement. It is ignored otherwise.";
	pattern "[^\*].*";
	}		}
	description
	"Name of administrative group that can be
	assigned to the user, and specified in
	an access control rule-list.";
	}
	typedef action-type {		/*
	type enumeration {		* Derived types
	enum permit {		*/
	description
	"Requested action is permitted.";
	}
	enum deny {
	description
	"Requested action is denied.";
			typedef user-name-type {
			type string {
			length "1..max";
	}		}
	}
	description
	"Action taken by the server when a particular
	rule matches.";
	}
	typedef node-instance-identifier {
	type yang:xpath1.0;
	description
	"Path expression used to represent a special
	data node instance identifier string.
	A node-instance-identifier value is an
	unrestricted YANG instance-identifier expression.
	All the same rules as an instance-identifier apply
	except predicates for keys are optional. If a key
	predicate is missing, then the node-instance-identifier
	represents all possible server instances for that key.
	This XPath expression is evaluated in the following context:
	o The set of namespace declarations are those in scope on
	the leaf element where this type is used.
	o The set of variable bindings contains one variable,
	'USER', which contains the name of user of the current
	session.
	o The function library is the core function library, but
	note that due to the syntax restrictions of an
	instance-identifier, no functions are allowed.
	o The context node is the root node in the data tree.";
	}
	container nacm {
	nacm:very-secure;
	description
	"Parameters for NETCONF Access Control Model.";
	leaf enable-nacm {
	type boolean;
	default true;
	description		description
	"Enable or disable all NETCONF access control		"General Purpose User Name string.";
	enforcement. If 'true', then enforcement
	is enabled. If 'false', then enforcement
	is disabled.";
	}		}
	leaf read-default {		typedef matchall-string-type {
	type action-type;		type string {
	default "permit";		pattern "\*";
			}
	description		description
	"Controls whether read access is granted if		"The string containing a single asterisk '*' is used
	no appropriate rule is found for a		to conceptually represent all possible values
	particular read request.";		for the particular leaf using this data type.";
	}		}
	leaf write-default {		typedef access-operations-type {
	type action-type;		type bits {
	default "deny";		bit create {
			description
			"Any protocol operation that creates a
			new data node.";
			}
			bit read {
			description
			"Any protocol operation or notification that
			returns the value of a data node.";
			}
			bit update {
			description
			"Any protocol operation that alters an existing
			data node.";
			}
			bit delete {
			description
			"Any protocol operation that removes a data node.";
			}
			bit exec {
			description
			"Execution access to the specified protocol operation.";
			}
			}
	description		description
	"Controls whether create, update, or delete access		"NETCONF Access Operation.";
	is granted if no appropriate rule is found for a
	particular write request.";
	}		}
	leaf exec-default {		typedef group-name-type {
	type action-type;		type string {
	default "permit";		length "1..max";
			pattern "[^\*].*";
			}
	description		description
	"Controls whether exec access is granted if no appropriate		"Name of administrative group to which
	rule is found for a particular RPC operation request.";		users can be assigned.";
	}		}
	leaf denied-rpcs {		typedef action-type {
	type yang:zero-based-counter32;		type enumeration {
	config false;		enum permit {
	mandatory true;		description
			"Requested action is permitted.";
			}
			enum deny {
			description
			"Requested action is denied.";
			}
			}
	description		description
	"Number of times an RPC operation request was denied		"Action taken by the server when a particular
	since the server last restarted.";		rule matches.";
	}		}
	leaf denied-data-writes {		typedef node-instance-identifier {
	type yang:zero-based-counter32;		type yang:xpath1.0;
	config false;
	mandatory true;
	description
	"Number of times a request to alter a data node
	was denied, since the server last restarted.";
	}
	leaf denied-notifications {
	type yang:zero-based-counter32;
	config false;
	mandatory true;
	description		description
	"Number of times a notification was denied		"Path expression used to represent a special
	since the server last restarted.";		data node instance identifier string.
			A node-instance-identifier value is an
			unrestricted YANG instance-identifier expression.
			All the same rules as an instance-identifier apply
			except predicates for keys are optional. If a key
			predicate is missing, then the node-instance-identifier
			represents all possible server instances for that key.
			This XPath expression is evaluated in the following context:
			o The set of namespace declarations are those in scope on
			the leaf element where this type is used.
			o The set of variable bindings contains one variable,
			'USER', which contains the name of user of the current
			session.
			o The function library is the core function library, but
			note that due to the syntax restrictions of an
			instance-identifier, no functions are allowed.
			o The context node is the root node in the data tree.";
	}		}
	container groups {		container nacm {
			nacm:default-deny-all;
	description		description
	"NETCONF Access Control Groups.";		"Parameters for NETCONF Access Control Model.";
	list group {		leaf enable-nacm {
	key name;		type boolean;
			default true;
			description
			"Enable or disable all NETCONF access control
			enforcement. If 'true', then enforcement
			is enabled. If 'false', then enforcement
			is disabled.";
			}
			leaf read-default {
			type action-type;
			default "permit";
	description		description
	"One NACM Group Entry.";		"Controls whether read access is granted if
			no appropriate rule is found for a
			particular read request.";
			}
	leaf name {		leaf write-default {
	type group-name-type;		type action-type;
	description		default "deny";
	"Group name associated with this entry.";		description
	}		"Controls whether create, update, or delete access
			is granted if no appropriate rule is found for a
			particular write request.";
			}
	leaf-list user-name {		leaf exec-default {
	type user-name-type;		type action-type;
	description		default "permit";
	"Each entry identifies the user name of		description
	a member of the group associated with		"Controls whether exec access is granted if no appropriate
	this entry.";		rule is found for a particular protocol operation request.";
	}		}
			leaf denied-operations {
			type yang:zero-based-counter32;
			config false;
			mandatory true;
			description
			"Number of times a protocol operation request was denied
			since the server last restarted.";
	}		}
	}
	list rule-list {		leaf denied-data-writes {
	key "name";		type yang:zero-based-counter32;
	ordered-by user;		config false;
	description		mandatory true;
	"An ordered collection of access control rules.";		description
			"Number of times a protocol operation request to alter
			a configuration datastore was denied, since the
			server last restarted.";
			}
	leaf name {		leaf denied-notifications {
	type string {		type yang:zero-based-counter32;
	length "1..256";		config false;
	}		mandatory true;
	description		description
	"Arbitrary name assigned to the rule-list.";		"Number of times a notification was dropped
			for a subscription because access to
			the event type was denied, since the server
			last restarted.";
	}		}
	leaf-list group {
	type union {		container groups {
	type matchall-string-type;
	type group-name-type;
	}
	description		description
	"List of administrative groups that will be		"NETCONF Access Control Groups.";
	assigned the associated access rights
	defined by the 'rule' list.
	The string '*' indicates that all groups apply to the		list group {
	entry.";		key name;
			description
			"One NACM Group Entry.";
			leaf name {
			type group-name-type;
			description
			"Group name associated with this entry.";
			}
			leaf-list user-name {
			type user-name-type;
			description
			"Each entry identifies the user name of
			a member of the group associated with
			this entry.";
			}
			}
	}		}
	list rule {		list rule-list {
	key "name";		key "name";
	ordered-by user;		ordered-by user;
	description		description
	"One access control rule.		"An ordered collection of access control rules.";
	Rules are processed in user-defined order until a match is
	found. A rule matches if 'module-name', 'rule-type', and
	'access-operations' matches the request. If a rule
	matches, the 'action' leaf determines if access is granted
	or not.";
	leaf name {		leaf name {
	type string {		type string {
	length "1..256";		length "1..max";
	}		}
	description		description
	"Arbitrary name assigned to the rule.";		"Arbitrary name assigned to the rule-list.";
	}		}
			leaf-list group {
	leaf module-name {
	type union {		type union {
	type matchall-string-type;		type matchall-string-type;
	type string;		type group-name-type;
	}		}
	default "*";
	description		description
	"Name of the module associated with this rule.		"List of administrative groups that will be
			assigned the associated access rights
			defined by the 'rule' list.
	This leaf matches if it has the value '*', or if the		The string '*' indicates that all groups apply to the
	object being accessed is defined in the module with the		entry.";
	specified module name.";
	}		}
	choice rule-type {
			list rule {
			key "name";
			ordered-by user;
	description		description
	"This choice matches if all leafs present in the rule		"One access control rule.
	matches the request. If no leafs are present, the
	choice matches all requests.";		Rules are processed in user-defined order until a match is
	case protocol-operation {		found. A rule matches if 'module-name', 'rule-type', and
	leaf rpc-name {		'access-operations' matches the request. If a rule
	type union {		matches, the 'action' leaf determines if access is granted
	type matchall-string-type;		or not.";
	type string;
	}		leaf name {
	description		type string {
	"This leaf matches if it has the value '*', or if its		length "1..max";
	value equals the requested RPC operation name.";
	}		}
			description
			"Arbitrary name assigned to the rule.";
	}		}
	case notification {
	leaf notification-name {		leaf module-name {
	type union {		type union {
	type matchall-string-type;		type matchall-string-type;
	type string;		type string;
	}
	description
	"This leaf matches if it has the value '*', or if its
	value equals the requested notification name.";
	}		}
			default "*";
			description
			"Name of the module associated with this rule.
			This leaf matches if it has the value '*', or if the
			object being accessed is defined in the module with the
			specified module name.";
	}		}
	case data-node {		choice rule-type {
	leaf path {		description
	type node-instance-identifier;		"This choice matches if all leafs present in the rule
	mandatory true;		matches the request. If no leafs are present, the
	description		choice matches all requests.";
	"Data Node Instance Identifier associated with the data		case protocol-operation {
	node controlled by this rule.		leaf rpc-name {
			type union {
			type matchall-string-type;
			type string;
			}
			description
			"This leaf matches if it has the value '*', or if
			its value equals the requested protocol operation
			name.";
			}
			}
			case notification {
			leaf notification-name {
			type union {
			type matchall-string-type;
			type string;
			}
			description
			"This leaf matches if it has the value '*', or if its
			value equals the requested notification name.";
			}
			}
			case data-node {
			leaf path {
			type node-instance-identifier;
			mandatory true;
			description
			"Data Node Instance Identifier associated with the
			data node controlled by this rule.
	Configuration data or state data instance		Configuration data or state data instance
	identifiers start with a top-level data node. A		identifiers start with a top-level data node. A
	complete instance identifier is required for this		complete instance identifier is required for this
	type of path value.		type of path value.
	The special value '/' refers to all possible data		The special value '/' refers to all possible data
	store contents.";		store contents.";
			}
	}		}
	}		}
	}
	leaf access-operations {		leaf access-operations {
	type union {		type union {
	type matchall-string-type;		type matchall-string-type;
	type access-operations-type;		type access-operations-type;
			}
			default "*";
			description
			"Access operations associated with this rule.
			This leaf matches if it has the value '*', or if the
			bit corresponding to the requested operation is set.";
	}		}
	default "*";
	description
	"Access operations associated with this rule.
	This leaf matches if it has the value '*', or if the		leaf action {
	bit corresponding to the requested operation is set.";		type action-type;
	}		mandatory true;
			description
			"The access control action associated with the
			rule. If a rule is determined to match a
			particular request, then this object is used
			to determine whether to permit or deny the
			request.";
			}
	leaf action {		leaf comment {
	type action-type;		type string;
	mandatory true;		description
	description		"A textual description of the access rule.";
	"The access control action associated with the		}
	rule. If a rule is determined to match a
	particular request, then this object is used
	to determine whether to permit or deny the
	request.";
	}
	leaf comment {
	type string;
	description
	"A textual description of the access rule.";
	}		}
	}		}
	}		}
	}		}
	}
	<CODE ENDS>		<CODE ENDS>
	Figure 5		Figure 5
	3.5. IANA Considerations		3.6. IANA Considerations
	There are two actions that are requested of IANA: This document		There are two actions that are requested of IANA: This document
	registers one URI in "The IETF XML Registry". Following the format		registers one URI in "The IETF XML Registry". Following the format
	in [RFC3688], the following has been registered.		in [RFC3688], the following has been registered.
	URI: urn:ietf:params:xml:ns:yang:ietf-netconf-acm		URI: urn:ietf:params:xml:ns:yang:ietf-netconf-acm
	Registrant Contact: The IESG.		Registrant Contact: The IESG.
	XML: N/A, the requested URI is an XML namespace.		XML: N/A, the requested URI is an XML namespace.
	This document registers one module in the "YANG Module Names"		This document registers one module in the "YANG Module Names"
	registry. Following the format in [RFC6020], the following has been		registry. Following the format in [RFC6020], the following has been
	registered.		registered.
	name: ietf-netconf-acm		name: ietf-netconf-acm
	namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-acm		namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-acm
	prefix: nacm		prefix: nacm
	reference: RFC XXXX		reference: RFC XXXX
	// RFC Ed.: Replace XXX with actual RFC number		// RFC Ed.: Replace XXX with actual RFC number
	// and remove this note		// and remove this note
	3.6. Security Considerations		3.7. Security Considerations
	This entire document discusses access control requirements and		This entire document discusses access control requirements and
	mechanisms for restricting NETCONF protocol behavior within a given		mechanisms for restricting NETCONF protocol behavior within a given
	session.		session.
			This section highlights the issues for an administrator to consider
			when configuring a NETCONF server with NACM.
			3.7.1. NACM Configuration and Monitoring Considerations
	Configuration of the access control system is highly sensitive to		Configuration of the access control system is highly sensitive to
	system security. A server may choose not to allow any user		system security. A server may choose not to allow any user
	configuration to some portions of it, such as the global security		configuration to some portions of it, such as the global security
	level, or the groups which allowed access to system resources.		level, or the groups which allowed access to system resources.
	This document incorporates the optional use of a "recovery session"		By default, NACM enforcement is enabled. By default, "read" access
	mechanism, which can be used to bypass access control enforcement in		to all datastore contents enabled, (unless "nacm:default-deny-all" is
	emergencies, such as NACM configuration errors which disable all		specified for the data definition) and "exec" access is enabled for
	access to the server. The configuration and identification of such a		safe protocol operations. An administrator needs to ensure that NACM
	recovery session mechanism are outside the scope of this document.		is enabled, and also decide if the default access parameters are set
			appropriately. Make sure the following data nodes are properly
			configured:
	There is a risk that invocation of non-standard protocol operations		o /nacm/enable-nacm (default "true")
	will have undocumented side effects. An administrator needs to
	construct access control rules such that the configuration datastore
	is protected from such side effects. Also, such protocol operations
	SHOULD never be invoked by a session during a "recovery session".
	There is a risk that non-standard protocol operations, or even the		o /nacm/read-default (default "permit")
	standard <get> operation, may return data which "aliases" or "copies"
	sensitive data from a different data object. In this case, the		o /nacm/write-default (default "deny")
	namespace and/or the element name will not match the values for the
	sensitive data, which is then fully or partially copied into a		o /nacm/exec-default (default "permit")
	different namespace and/or element. An administrator needs to avoid
	using data models which use this practice.
	An administrator needs to restrict write access to all configurable		An administrator needs to restrict write access to all configurable
	objects within this data model.		objects within this data model.
	If write access is allowed for configuration of access control rules,		If write access is allowed for configuration of access control rules,
	then care needs to be taken not to disrupt the access control		then care needs to be taken not to disrupt the access control
	enforcement.		enforcement. For example, if the NACM access control rules are
			editing directly within the running configuration datastore (i.e.,
			:writable-running capability is supported and used), then care needs
			to be taken not to allow unintended access while the edits are being
			done.
			NACM requires some a user name in each NACM group mapping. An
			administrator needs to make sure that the translation from a
			transport or implementation dependant user identity to a NACM user
			name is unique.
	An administrator needs to restrict read access to the following		An administrator needs to restrict read access to the following
	objects within this data model, which reveal access control		objects within this data model, which reveal access control
	configuration which could be considered sensitive.		configuration which could be considered sensitive.
	o enable-nacm		o /nacm/enable-nacm
	o read-default		o /nacm/read-default
	o write-default		o /nacm/write-default
	o exec-default		o /nacm/exec-default
	o groups		o /nacm/groups
	o rules		o /nacm/rule-list
			3.7.2. General Configuration Issues
			There is a risk that invocation of non-standard protocol operations
			will have undocumented side effects. An administrator needs to
			construct access control rules such that the configuration datastore
			is protected from such side effects.
			It is possible for a session with some write access (e.g., allowed to
			invoke <edit-config>), but without any access to a particular
			datastore subtree containing sensitive data, to determine the
			presence or non-presence of that data. This can be done by
			repeatedly issuing some sort of edit request (create, update, or
			delete) and possibly receiving "access-denied" errors in response.
			These "fishing" attacks can identify the presence or non-presence of
			specific sensitive data even without the "error-path" field being
			present within the "rpc-error" response.
			It is possible that the data model definition itself (e.g., YANG
			when-stmt) will help an unauthorized session determine the presence
			or even value of sensitive data nodes by examining the presence and
			values of different data nodes.
			There is a risk that non-standard protocol operations, or even the
			standard <get> protocol operation, may return data which "aliases" or
			"copies" sensitive data from a different data object. There may
			simply be multiple data model definitions which expose or even
			configure the same underlying system instrumentation.
			A data model may contain external keys (e.g., YANG leafref), which
			expose values from a different data structure. An administrator
			needs to be aware of sensitive data models which contain leafref
			nodes. This entails finding all the leafref objects that "point" at
			the sensitive data (i.e., "path-stmt" values that implicitly or
			explicitly include the sensitive data node.
			It is beyond the scope of this document to define access control
			enforcement procedures for underlying device instrumentation that may
			exist to support the NETCONF server operation. An administrator can
			identify each protocol operation that the server provides, and decide
			if it needs any access control applied to it.
			This document incorporates the optional use of a "recovery session"
			mechanism, which can be used to bypass access control enforcement in
			emergencies, such as NACM configuration errors which disable all
			access to the server. The configuration and identification of such a
			recovery session mechanism are implementation-specific and outside
			the scope of this document. An administrator needs to be aware of
			any "recovery session" mechanisms available on the device, and make
			sure they are used appropriately.
			It is possible for a session to disrupt configuration management,
			even without any write access to the configuration, by locking the
			datastore. This may be done to insure all or part of the
			configuration remains stable while it is being retrieved, ot it may
			be done as a "denial-of-service" attack. There is no way for the
			server to know the difference. An administrator may wish to restrict
			"exec" access to the following protocol operations:
			o <lock>
			o <unlock>
			o <partial-lock>
			o <partial-unlock>
			3.7.3. Data Model Design Considerations
			Designers need to clearly identify any sensitive data, notifications,
			or protocol operations defined within a YANG module. For such
			definitions, a "nacm:default-deny-write" or "nacm:default-deny-all"
			statement SHOULD be present, in addition to a clear description of
			the security risks.
			Protocol operations need to be properly documented by the data model
			designer, so it is clear to administrators what data nodes (if any)
			are affected by the protocol operation, and what information (if any)
			is returned in the <rpc-reply> message.
			Data models ought to be designed so that different access levels for
			input parameters to protocol operations is not required. Use of
			generic protocol operations should be avoided, and separate protocol
			operations defined instead, if different access levels are needed.
	4. References		4. References
	4.1. Normative References		4.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,		[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
	January 2004.		January 2004.
	skipping to change at page 41, line 25		skipping to change at page 41, line 25
	[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event		[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
	Notifications", RFC 5277, July 2008.		Notifications", RFC 5277, July 2008.
	[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the		[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
	Network Configuration Protocol (NETCONF)", RFC 6020,		Network Configuration Protocol (NETCONF)", RFC 6020,
	October 2010.		October 2010.
	[RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,		[RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
	October 2010.		October 2010.
	[I-D.ietf-netconf-4741bis]		[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
	Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
	Bierman, "Network Configuration Protocol (NETCONF)",		Bierman, "Network Configuration Protocol (NETCONF)",
	draft-ietf-netconf-4741bis-10 (work in progress),		RFC 6241, June 2011.
	March 2011.
	[I-D.ietf-netconf-rfc4742bis]		[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
	Wasserman, M. and T. Goddard, "Using the NETCONF		Shell (SSH)", RFC 6242, June 2011.
	Configuration Protocol over Secure Shell (SSH)",
	draft-ietf-netconf-rfc4742bis-08 (work in progress),
	March 2011.
	4.2. Informative References		4.2. Informative References
	[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,		[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
	"Remote Authentication Dial In User Service (RADIUS)",		"Remote Authentication Dial In User Service (RADIUS)",
	RFC 2865, June 2000.		RFC 2865, June 2000.
	[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In		[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In
	User Service (RADIUS) Authorization for Network Access		User Service (RADIUS) Authorization for Network Access
	Server (NAS) Management", RFC 5607, July 2009.		Server (NAS) Management", RFC 5607, July 2009.
	skipping to change at page 42, line 28		skipping to change at page 42, line 28
	<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">		<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
	<groups>		<groups>
	<group>		<group>
	<name>admin</name>		<name>admin</name>
	<user-name>admin</user-name>		<user-name>admin</user-name>
	<user-name>andy</user-name>		<user-name>andy</user-name>
	</group>		</group>
	<group>		<group>
	<name>monitor</name>		<name>limited</name>
	<user-name>wilma</user-name>		<user-name>wilma</user-name>
	<user-name>bam-bam</user-name>		<user-name>bam-bam</user-name>
	</group>		</group>
	<group>		<group>
	<name>guest</name>		<name>guest</name>
	<user-name>guest</user-name>		<user-name>guest</user-name>
	<user-name>guest@example.com</user-name>		<user-name>guest@example.com</user-name>
	</group>		</group>
	</groups>		</groups>
	</nacm>		</nacm>
	This example shows 3 groups:		This example shows 3 groups:
	1. The "admin" group contains 2 users named "admin" and "andy".		1. The "admin" group contains 2 users named "admin" and "andy".
	2. The "monitor" group contains 2 users named "wilma" and "bam-bam".		2. The "limited" group contains 2 users named "wilma" and "bam-bam".
	3. The "guest" group contains 2 users named "guest" and		3. The "guest" group contains 2 users named "guest" and
	"guest@example.com".		"guest@example.com".
	A.2. Module Rule Example		A.2. Module Rule Example
	Module rules are used to control access to all the content defined in		Module rules are used to control access to all the content defined in
	a specific module. A module rule has the <module-name> leaf set, but		a specific module. A module rule has the <module-name> leaf set, but
	no case in the "rule-type" choice.		no case in the "rule-type" choice.
	<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">		<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
	<rule-list>		<rule-list>
	<name>guest</name>		<name>guest-acl</name>
	<group>guest</group>		<group>guest</group>
	<rule>		<rule>
	<name>mod-1</name>		<name>deny-ncm</name>
	<module-name>ietf-netconf-monitoring</module-name>		<module-name>ietf-netconf-monitoring</module-name>
	<access-operations>*</access-operations>		<access-operations>*</access-operations>
	<action>deny</action>		<action>deny</action>
	<comment>		<comment>
	Do not allow guests any access to the netconf		Do not allow guests any access to the netconf
	monitoring information.		monitoring information.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	<rule-list>		<rule-list>
	<name>monitor example</name>		<name>limited-acl</name>
	<group>monitor</group>		<group>limited</group>
	<rule>		<rule>
	<name>mod-2</name>		<name>permit-ncm</name>
	<module-name>ietf-netconf-monitoring</module-name>		<module-name>ietf-netconf-monitoring</module-name>
	<access-operations>read</access-operations>		<access-operations>read</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow read access to the netconf		Allow read access to the netconf
	monitoring information.		monitoring information.
	</comment>		</comment>
	</rule>		</rule>
	<rule>		<rule>
	<name>mod-3</name>		<name>permit-exec</name>
	<module-name>*</module-name>		<module-name>*</module-name>
	<access-operations>exec</access-operations>		<access-operations>exec</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow invocation of the		Allow invocation of the
	supported server operations.		supported server operations.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	<rule-list>		<rule-list>
	<name>admin example</name>		<name>admin-acl</name>
	<group>admin</group>		<group>admin</group>
	<rule>		<rule>
	<name>mod-4</name>		<name>permit-all</name>
	<module-name>*</module-name>		<module-name>*</module-name>
	<access-operations>*</access-operations>		<access-operations>*</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow the admin group complete access to all		Allow the admin group complete access to all
	operations and data.		operations and data.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	</nacm>		</nacm>
	This example shows 4 module rules:		This example shows 4 module rules:
	mod-1: This rule prevents the guest group from reading any		deny-ncm: This rule prevents the "guest" group from reading any
	monitoring information in the ietf-netconf-monitoring YANG module.		monitoring information in the "ietf-netconf-monitoring" YANG
			module.
	mod-2: This rule allows the monitor group to read the ietf-netconf-		permit-ncm: This rule allows the "limited" group to read the "ietf-
	monitoring YANG module.		netconf-monitoring" YANG module.
	mod-3: This rule allows the monitor group to invoke any protocol		permit-exec: This rule allows the "limited" group to invoke any
	operation supported by the server.		protocol operation supported by the server.
	mod-4: This rule allows the admin group complete access to all		permit-all: This rule allows the "admin" group complete access to
	content in the server. No subsequent rule will match for the		all content in the server. No subsequent rule will match for the
	admin group, because of this module rule.		"admin" group, because of this module rule.
	A.3. RPC Rule Example		A.3. RPC Rule Example
	RPC rules are used to control access to a specific protocol		RPC rules are used to control access to a specific protocol
	operation.		operation.
	<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">		<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
	<rule-list>		<rule-list>
	<name>guest</name>		<name>guest-limited-acl</name>
	<group>monitor</group>		<group>limited</group>
	<group>guest</group>		<group>guest</group>
	<rule>		<rule>
	<name>rpc-1</name>		<name>deny-kill-session</name>
	<module-name>ietf-netconf</module-name>		<module-name>ietf-netconf</module-name>
	<rpc-name>kill-session</rpc-name>		<rpc-name>kill-session</rpc-name>
	<access-operations>exec</access-operations>		<access-operations>exec</access-operations>
	<action>deny</action>		<action>deny</action>
	<comment>		<comment>
	Do not allow the monitor or guest group		Do not allow the limited or guest group
	to kill another session.		to kill another session.
	</comment>		</comment>
	</rule>		</rule>
	<rule>		<rule>
	<name>rpc-2</name>		<name>deny-delete-config</name>
	<module-name>ietf-netconf</module-name>		<module-name>ietf-netconf</module-name>
	<rpc-name>delete-config</rpc-name>		<rpc-name>delete-config</rpc-name>
	<access-operations>exec</access-operations>		<access-operations>exec</access-operations>
	<action>deny</action>		<action>deny</action>
	<comment>		<comment>
	Do not allow monitor or guest group		Do not allow limited or guest group
	to delete any configurations.		to delete any configurations.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	<rule-list>		<rule-list>
	<name>monitor</name>		<name>limited-acl</name>
	<group>monitor</group>		<group>limited</group>
	<rule>		<rule>
	<name>rpc-3</name>		<name>permit-edit-config</name>
	<module-name>ietf-netconf</module-name>		<module-name>ietf-netconf</module-name>
	<rpc-name>edit-config</rpc-name>		<rpc-name>edit-config</rpc-name>
	<access-operations>exec</access-operations>		<access-operations>exec</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow the monitor group to edit the configuration.		Allow the limited group to edit the configuration.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	</nacm>		</nacm>
	This example shows 3 protocol operation rules:		This example shows 3 protocol operation rules:
	rpc-1: This rule prevents the monitor or guest groups from invoking		deny-kill-session: This rule prevents the "limited" or "guest"
	the NETCONF <kill-session> protocol operation.		groups from invoking the NETCONF <kill-session> protocol
			operation.
	rpc-2: This rule prevents the monitor or guest groups from invoking		deny-delete-config: This rule prevents the "limited" or "guest"
	the NETCONF <delete-config> protocol operation.		groups from invoking the NETCONF <delete-config> protocol
			operation.
	rpc-3: This rule allows the monitor group to invoke the NETCONF		permit-edit-config: This rule allows the "limited" group to invoke
	<edit-config> protocol operation. This rule will have no real		the NETCONF <edit-config> protocol operation. This rule will have
	effect unless the "exec-default" leaf is set to "deny".		no real effect unless the "exec-default" leaf is set to "deny".
	A.4. Data Rule Example		A.4. Data Rule Example
	Data rules are used to control access to specific (config and non-		Data rules are used to control access to specific (config and non-
	config) data nodes within the NETCONF content provided by the server.		config) data nodes within the NETCONF content provided by the server.
	<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">		<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
	<rule-list>		<rule-list>
	<name>guest rules</name>		<name>guest-acl</name>
	<group>guest</group>		<group>guest</group>
	<rule>		<rule>
	<name>data-1</name>		<name>deny-nacm</name>
	<path xmlns:n="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">		<path xmlns:n="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
	/n:nacm		/n:nacm
	</path>		</path>
	<access-operations>*</access-operations>		<access-operations>*</access-operations>
	<action>deny</action>		<action>deny</action>
	<comment>		<comment>
	Deny the guest group any access to the /nacm data.		Deny the guest group any access to the /nacm data.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	<rule-list>		<rule-list>
	<name>monitor rules</name>		<name>limited-acl</name>
	<group>monitor</group>		<group>limited</group>
	<rule>		<rule>
	<name>data-acme-config</name>		<name>permit-acme-config</name>
	<path xmlns:acme="http://example.com/ns/netconf">		<path xmlns:acme="http://example.com/ns/netconf">
	/acme:acme-netconf/acme:config-parameters		/acme:acme-netconf/acme:config-parameters
	</path>		</path>
	<access-operations>		<access-operations>
	read create update delete		read create update delete
	</access-operations>		</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow the monitor group complete access to the acme		Allow the limited group complete access to the acme
	netconf configuration parameters. Showing long form		netconf configuration parameters. Showing long form
	of 'access-operations' instead of shorthand.		of 'access-operations' instead of shorthand.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	<rule-list>		<rule-list>
	<name>dummy-itf</name>		<name>guest-limited-acl</name>
	<group>guest monitor</group>		<group>guest</group>
			<group>limited</group>
	<rule>		<rule>
	<name>dummy-itf</name>		<name>permit-dummy-interface</name>
	<path xmlns:acme="http://example.com/ns/itf">		<path xmlns:acme="http://example.com/ns/itf">
	/acme:interfaces/acme:interface[acme:name='dummy']		/acme:interfaces/acme:interface[acme:name='dummy']
	</path>		</path>
	<access-operations>read update</access-operations>		<access-operations>read update</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow the monitor and guest groups read		Allow the limited and guest groups read
	and update access to the dummy interface.		and update access to the dummy interface.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	<rule-list>		<rule-list>
	<name>admin rules</name>		<name>admin-acl</name>
	<rule>		<rule>
	<name>admin-itf</name>		<name>permit-interface</name>
	<path xmlns:acme="http://example.com/ns/itf">		<path xmlns:acme="http://example.com/ns/itf">
	/acme:interfaces/acme:interface		/acme:interfaces/acme:interface
	</path>		</path>
	<access-operations>*</access-operations>		<access-operations>*</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow admin full access to all acme interfaces.		Allow admin full access to all acme interfaces.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	skipping to change at page 47, line 46		skipping to change at page 48, line 4
	/acme:interfaces/acme:interface		/acme:interfaces/acme:interface
	</path>		</path>
	<access-operations>*</access-operations>		<access-operations>*</access-operations>
	<action>permit</action>		<action>permit</action>
	<comment>		<comment>
	Allow admin full access to all acme interfaces.		Allow admin full access to all acme interfaces.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	</nacm>		</nacm>
	This example shows 4 data rules:		This example shows 4 data rules:
	data-1: This rule denies the guest group any access to the <nacm>		deny-nacm: This rule denies the "guest" group any access to the
	subtree. Note that the default namespace is only applicable		<nacm> subtree. Note that the default namespace is only
	because this subtree is defined in the same namespace as the		applicable because this subtree is defined in the same namespace
	<data-rule> element.		as the <data-rule> element.
	data-acme-config: This rule gives the monitor group read-write		permit-acme-config: This rule gives the "limited" group read-write
	access to the acme <config-parameters>.		access to the acme <config-parameters>.
	dummy-itf: This rule gives the monitor and guest groups read-update		permit-dummy-interface: This rule gives the "limited" and "guest"
	access to the acme <interface>. entry named "dummy". This entry		groups read-update access to the acme <interface>. entry named
	cannot be created or deleted by these groups, just altered.		"dummy". This entry cannot be created or deleted by these groups,
			just altered.
	admin-itf: This rule gives the admin group read-write access to all		permit-interface: This rule gives the "admin" group read-write
	acme <interface>. entries. This is an example of an unreachable		access to all acme <interface>. entries. This is an example of an
	rule because the "mod-3" rule already gives the admin group full		unreachable rule because the "mod-3" rule already gives the
	access to this data.		"admin" group full access to this data.
	A.5. Notification Rule Example		A.5. Notification Rule Example
	Notification rules are used to control access to a specific		Notification rules are used to control access to a specific
	notification event type.		notification event type.
	<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">		<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
	<rule-list>		<rule-list>
	<name>sys</name>		<name>sys-acl</name>
	<group>monitor</group>		<group>limited</group>
	<group>guest</group>		<group>guest</group>
	<rule>		<rule>
	<name>notif-1</name>		<name>deny-config-change</name>
	<module-name>acme-system</module-name>		<module-name>acme-system</module-name>
	<notification-name>sys-config-change</notification-name>		<notification-name>sys-config-change</notification-name>
	<access-operations>read</access-operations>		<access-operations>read</access-operations>
	<action>deny</action>		<action>deny</action>
	<comment>		<comment>
	Do not allow the guest or monitor groups		Do not allow the guest or limited groups
	to receive config change events.		to receive config change events.
	</comment>		</comment>
	</rule>		</rule>
	</rule-list>		</rule-list>
	</nacm>		</nacm>
	This example shows 1 notification rule:		This example shows 1 notification rule:
	notif-1: This rule prevents the monitor or guest groups from		deny-config-change: This rule prevents the "limited" or "guest"
	receiving the acme <sys-config-change> event type.		groups from receiving the acme <sys-config-change> event type.
	Appendix B. Change Log		Appendix B. Change Log
	-- RFC Ed.: remove this section before publication.		-- RFC Ed.: remove this section before publication.
	B.1. 03-04		B.1. 04-05
			Updated Security Considerations section.
			Changed term 'operator' to 'administrator'.
			Used the terms "access operation" and "protocol operation"
			consistently.
			Moved some normative text from section 2 to section 3. Also made it
			more clear that section 2 is not a requirements section, but
			documentation of the objectives for NACM.
			Renamed "nacm:secure" to "nacm:default-deny-write", and "nacm:very-
			secure" to "nacm:default-deny-all". Explained that "nacm:default-
			deny-write" is ignored on rpc statements.
			Described that <kill-session> and <delete-config> behave as if
			specified with "nacm:default-deny-all".
			B.2. 03-04
	Introduced rule-lists to group related rules together.		Introduced rule-lists to group related rules together.
	Moved "module-rule", "rpc-rule", "notification-rule", and "data-rule"		Moved "module-rule", "rpc-rule", "notification-rule", and "data-rule"
	into one common "rule", with a choice to select between the four		into one common "rule", with a choice to select between the four
	variants.		variants.
	Changed "superuser" to "recovery session", and adjusted text		Changed "superuser" to "recovery session", and adjusted text
	throughout document for this change.		throughout document for this change.
	Clarified behavior of global default NACM parameters, enable-nacm,		Clarified behavior of global default NACM parameters, enable-nacm,
	read-default, write-default, exec-default.		read-default, write-default, exec-default.
	Clarified when access control is applied during system		Clarified when access control is applied during system
	initialization.		initialization.
	B.2. 02-03		B.3. 02-03
	Fixed improper usage of RFC 2119 keywords.		Fixed improper usage of RFC 2119 keywords.
	Changed term usage of "database" to "datastore".		Changed term usage of "database" to "datastore".
	Clarified that "secure" and "very-secure" extensions only apply if		Clarified that "secure" and "very-secure" extensions only apply if
	the /nacm/enable-nacm object is "true".		the /nacm/enable-nacm object is "true".
	B.3. 01-02		B.4. 01-02
	Removed authentication text and objects.		Removed authentication text and objects.
	Changed module name from ietf-nacm to ietf-netconf-acm.		Changed module name from ietf-nacm to ietf-netconf-acm.
	Updated NETCONF and YANG terminology.		Updated NETCONF and YANG terminology.
	Removed open issues section.		Removed open issues section.
	Changed some must to MUST in requirements section.		Changed some must to MUST in requirements section.
	B.4. 00-01		B.5. 00-01
	Updated YANG anf YANG Types references.		Updated YANG anf YANG Types references.
	Updated module namespace URI to standard format.		Updated module namespace URI to standard format.
	Updated module header meta-data to standard format.		Updated module header meta-data to standard format.
	Filled in IANA section.		Filled in IANA section.
	B.5. 00		B.6. 00
	Initial version cloned from		Initial version cloned from
	draft-bierman-netconf-access-control-02.txt.		draft-bierman-netconf-access-control-02.txt.
	Authors' Addresses		Authors' Addresses
	Andy Bierman		Andy Bierman
	Brocade		Brocade
	Email: andy.bierman@brocade.com		Email: andy.bierman@brocade.com
End of changes. 288 change blocks.
	1020 lines changed or deleted		1043 lines changed or added
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