draft-ietf-netconf-access-control-01.txt   draft-ietf-netconf-access-control-02.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: April 28, 2011 Tail-f Systems Expires: August 7, 2011 Tail-f Systems
October 25, 2010 February 3, 2011
Network Configuration Protocol Access Control Model Network Configuration Protocol Access Control Model
draft-ietf-netconf-access-control-01 draft-ietf-netconf-access-control-02
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, which promotes human usability and multi-vendor environment, which 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 operations and content.
This document discusses requirements for a suitable access control This document discusses requirements for a suitable access control
skipping to change at page 1, line 38 skipping to change at page 1, line 38
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 April 28, 2011. This Internet-Draft will expire on August 7, 2011.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.1. Requirements Notation . . . . . . . . . . . . . . . . 5 1.1.1. Requirements Notation . . . . . . . . . . . . . . . . 4
1.1.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . 5 1.1.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . 4
1.1.3. NACM Terms . . . . . . . . . . . . . . . . . . . . . . 6 1.1.3. YANG Terms . . . . . . . . . . . . . . . . . . . . . . 5
2. Authentication Requirements . . . . . . . . . . . . . . . . . 7 1.1.4. NACM Terms . . . . . . . . . . . . . . . . . . . . . . 5
3. Access Control Requirements . . . . . . . . . . . . . . . . . 8 2. Access Control Requirements . . . . . . . . . . . . . . . . . 6
3.1. Protocol Control Points . . . . . . . . . . . . . . . . . 8 2.1. Protocol Control Points . . . . . . . . . . . . . . . . . 6
3.2. Simplicity . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2. Simplicity . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Procedural Interface . . . . . . . . . . . . . . . . . . . 9 2.3. Procedural Interface . . . . . . . . . . . . . . . . . . . 7
3.4. Database Access . . . . . . . . . . . . . . . . . . . . . 9 2.4. Datastore Access . . . . . . . . . . . . . . . . . . . . . 7
3.4.1. Access Rights . . . . . . . . . . . . . . . . . . . . 10 2.4.1. Access Rights . . . . . . . . . . . . . . . . . . . . 8
3.4.2. <get> and <get-config> Operations . . . . . . . . . . 10 2.4.2. <get> and <get-config> Operations . . . . . . . . . . 8
3.4.3. <edit-config> Operation . . . . . . . . . . . . . . . 10 2.4.3. <edit-config> Operation . . . . . . . . . . . . . . . 8
3.4.4. <copy-config> Operation . . . . . . . . . . . . . . . 11 2.4.4. <copy-config> Operation . . . . . . . . . . . . . . . 9
3.5. Users and Groups . . . . . . . . . . . . . . . . . . . . . 12 2.5. Users and Groups . . . . . . . . . . . . . . . . . . . . . 10
3.6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . 12 2.6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . 10
3.7. Configuration Capabilities . . . . . . . . . . . . . . . . 12 2.7. Configuration Capabilities . . . . . . . . . . . . . . . . 10
3.8. Identifying Security Holes . . . . . . . . . . . . . . . . 13 2.8. Identifying Security Holes . . . . . . . . . . . . . . . . 11
3.9. Data Shadowing . . . . . . . . . . . . . . . . . . . . . . 13 2.9. Data Shadowing . . . . . . . . . . . . . . . . . . . . . . 12
3.10. NETCONF Specific Requirements . . . . . . . . . . . . . . 14 2.10. NETCONF Specific Requirements . . . . . . . . . . . . . . 12
4. NETCONF Authentication and Authorization Model . . . . . . . . 15 3. NETCONF Access Control Model (NACM) . . . . . . . . . . . . . 14
4.1. SSH Public Key Authentication . . . . . . . . . . . . . . 15 3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 14
4.2. Local User Password Authentication . . . . . . . . . . . . 16 3.1.1. Features . . . . . . . . . . . . . . . . . . . . . . . 14
4.3. RADIUS Password Authentication and Service 3.1.2. External Dependencies . . . . . . . . . . . . . . . . 15
Authorization . . . . . . . . . . . . . . . . . . . . . . 16 3.1.3. Message Processing Model . . . . . . . . . . . . . . . 15
4.3.1. Operation . . . . . . . . . . . . . . . . . . . . . . 16 3.2. Model Components . . . . . . . . . . . . . . . . . . . . . 17
5. NETCONF Access Control Model (NACM) . . . . . . . . . . . . . 18 3.2.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.2. Groups . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.1. Features . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.3. Sessions . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.2. External Dependencies . . . . . . . . . . . . . . . . 19 3.2.4. Access Permissions . . . . . . . . . . . . . . . . . . 18
5.1.3. Message Processing Model . . . . . . . . . . . . . . . 19 3.2.5. Global Enforcement Controls . . . . . . . . . . . . . 19
5.2. Model Components . . . . . . . . . . . . . . . . . . . . . 21 3.2.6. Access Control Rules . . . . . . . . . . . . . . . . . 19
5.2.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 21 3.3. Access Control Enforcement Procedures . . . . . . . . . . 19
5.2.2. Groups . . . . . . . . . . . . . . . . . . . . . . . . 22 3.3.1. Initial Operation . . . . . . . . . . . . . . . . . . 19
5.2.3. Sessions . . . . . . . . . . . . . . . . . . . . . . . 22 3.3.2. Session Establishment . . . . . . . . . . . . . . . . 20
5.2.4. Access Permissions . . . . . . . . . . . . . . . . . . 22 3.3.3. 'access-denied' Error Handling . . . . . . . . . . . . 20
5.2.5. Global Enforcement Controls . . . . . . . . . . . . . 23 3.3.4. Incoming RPC Message Validation . . . . . . . . . . . 20
5.2.6. Access Control Rules . . . . . . . . . . . . . . . . . 23 3.3.5. Data Node Access Validation . . . . . . . . . . . . . 23
5.3. Access Control Enforcement Procedures . . . . . . . . . . 23 3.3.6. Outgoing <rpc-reply> Authorization . . . . . . . . . . 26
5.3.1. Initial Operation . . . . . . . . . . . . . . . . . . 24 3.3.7. Outgoing <notification> Authorization . . . . . . . . 26
5.3.2. Session Establishment . . . . . . . . . . . . . . . . 24 3.4. Data Model Definitions . . . . . . . . . . . . . . . . . . 29
5.3.3. 'access-denied' Error Handling . . . . . . . . . . . . 24 3.4.1. High Level Procedures . . . . . . . . . . . . . . . . 29
5.3.4. Incoming RPC Message Validation . . . . . . . . . . . 24 3.4.2. Data Organization . . . . . . . . . . . . . . . . . . 29
5.3.5. Data Node Access Validation . . . . . . . . . . . . . 27 3.4.3. YANG Module . . . . . . . . . . . . . . . . . . . . . 30
5.3.6. Outgoing <rpc-reply> Authorization . . . . . . . . . . 29 3.5. IANA Considerations . . . . . . . . . . . . . . . . . . . 41
5.3.7. Outgoing <notification> Authorization . . . . . . . . 30 3.6. Security Considerations . . . . . . . . . . . . . . . . . 41
5.4. Data Model Definitions . . . . . . . . . . . . . . . . . . 33 4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.4.1. High Level Procedures . . . . . . . . . . . . . . . . 33 4.1. Normative References . . . . . . . . . . . . . . . . . . . 44
5.4.2. Data Organization . . . . . . . . . . . . . . . . . . 33 4.2. Informative References . . . . . . . . . . . . . . . . . . 44
5.4.3. YANG Module . . . . . . . . . . . . . . . . . . . . . 34 Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 45
5.5. IANA Considerations . . . . . . . . . . . . . . . . . . . 50 A.1. <groups> Example . . . . . . . . . . . . . . . . . . . . . 45
5.6. Security Considerations . . . . . . . . . . . . . . . . . 50 A.2. <module-rule> Example . . . . . . . . . . . . . . . . . . 46
6. Normative References . . . . . . . . . . . . . . . . . . . . . 52 A.3. <rpc-rule> Example . . . . . . . . . . . . . . . . . . . . 47
Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 53 A.4. <data-rule> Example . . . . . . . . . . . . . . . . . . . 49
A.1. <groups> Example . . . . . . . . . . . . . . . . . . . . . 53 A.5. <notification-rule> Example . . . . . . . . . . . . . . . 51
A.2. <module-rule> Example . . . . . . . . . . . . . . . . . . 54 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 52
A.3. <rpc-rule> Example . . . . . . . . . . . . . . . . . . . . 55 B.1. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 52
A.4. <data-rule> Example . . . . . . . . . . . . . . . . . . . 57 B.2. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 52
A.5. <notification-rule> Example . . . . . . . . . . . . . . . 59 B.3. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Appendix B. Open Issues . . . . . . . . . . . . . . . . . . . . . 60 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 53
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 61
C.1. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 61
C.2. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 62
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 operations and content that each user is authorized to
use. use.
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 operator selected portions of the available NETCONF content
within a particular server. within a particular server.
This document addresses NETCONF protocol authentication and access This document addresses access control mechanisms for the Operation
control mechanisms for the Operation and Content layers, as defined and Content layers of NETCONF, as defined in
in [RFC4741], and [RFC5277]. It contains five main sections: [I-D.ietf-netconf-4741bis], and [RFC5277]. It contains three main
sections:
1. Authentication Requirements
2. Access Control Requirements
3. NETCONF Authentication and Authorization Model 1. Access Control Requirements
4. NETCONF Access Control Model (NACM) 2. NETCONF Access Control Model (NACM)
5. YANG Data Model (ietf-nacm.yang) 3. YANG Data Model (ietf-netconf-acm.yang)
1.1. Terminology 1.1. Terminology
1.1.1. Requirements Notation 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 1.1.2. NETCONF Terms
The following terms are defined in RFC 4741 and are not redefined The following terms are defined in [I-D.ietf-netconf-4741bis] and are
here: not redefined here:
o client o client
o datastore
o operation o operation
o RPC operation o protocol operation
o server o server
o session o session
o user o user
1.1.3. NACM Terms 1.1.3. YANG Terms
The following terms are defined in [RFC6020] and are not redefined
here:
o data node
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,
which allows an operator to restrict access to a subset of all which allows an operator 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 operator to
enforce a particular access control policy. enforce a particular access control policy.
skipping to change at page 7, line 5 skipping to change at page 6, line 5
access control rule: The conceptual criteria used to determine if a access control rule: The conceptual criteria used to determine if a
particular NETCONF protocol operation should be permitted or particular NETCONF protocol operation should be permitted or
denied. denied.
authentication: The process of verifying a user's identity. authentication: The process of verifying a user's identity.
superuser: The special administrative user account which is given superuser: The special administrative user account which is given
unlimited NETCONF access, and is exempt from all access control unlimited NETCONF access, and is exempt from all access control
enforcement. enforcement.
2. Authentication Requirements 2. Access Control Requirements
The authentication mechanism must support password authentication
over RADIUS, to support deployment scenarios with centralized
authentication servers. Additionally, local users must be supported,
for scenarios when no centralized authentication server exists, or
for situations where the centralized authentication server cannot be
reached from the device.
Since the mandatory transport protocol for NETCONF is SSH NETCONF
Over SSH [RFC4742], the authentication model must support SSH's
"publickey" and "password" authentication methods [RFC4252]
The model for authentication configuration should be flexible enough
to support authentication methods defined by other standard documents
or by vendors.
3. Access Control Requirements
3.1. Protocol Control Points 2.1. Protocol Control Points
The NETCONF protocol allows new operations to be added at any time, The NETCONF protocol allows new operations to be added at any time,
and the YANG data modeling language supports this feature. It is not and 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 which only focuses on a static
set of operations, like some other protocols. Since few assumptions set of operations, like some other protocols. Since few assumptions
can be made about an arbitrary protocol operation, the NETCONF can be made about an arbitrary protocol operation, the NETCONF
architectural server components must be protected at several architectural server components must be protected at several
conceptual control points. conceptual control points.
+-------------+ +-------------+ +-------------+ +-------------+
client | RPC | | prune | client client | protocol | | prune | client
request --> | operation | | restricted | ---> reply request --> | operation | | restricted | ---> reply
| allowed? | | <rpc-reply> | | allowed? | | <rpc-reply> |
+-------------+ | nodes? | +-------------+ | nodes? |
| +-------------+ | +-------------+
| if any database or | if any datastore or
| state data is accessed | state data is accessed
| by the operation | by the operation
V V
+-------------+ +----------------+ +-------------+ +----------------+
| data node | | prune | | data node | | prune |
| access | | restricted | | access | | restricted |
| allowed? | | <notification> | ---> client | allowed? | | <notification> | ---> client
+-------------+ | event or data? | session +-------------+ | event or data? | session
+----------------+ +----------------+
Figure 1 Figure 1
The following access control points are defined: The following access control points are defined:
RPC operation: Configurable permission to invoke specific RPC protocol operation: Configurable permission to invoke specific
operations is required. Wildcard or multiple target mechanisms to protocol operations is required. Wildcard or multiple target
reduce configuration and effort are also required. mechanisms to reduce configuration and effort are also required.
NETCONF database: Configurable permission to read and/or alter NETCONF datastore: Configurable permission to read and/or alter
specific data nodes within any conceptual database is required. specific data nodes within any conceptual datastore is required.
Wildcard or multiple target mechanisms to reduce configuration and Wildcard or multiple target mechanisms to reduce configuration and
effort are also required. effort are also required.
RPC Reply Content: Configurable permission to read specific data RPC Reply Content: Configurable permission to read specific data
nodes within any conceptual RPC output section is required. nodes within any conceptual RPC output section is required.
Unauthorized data is silently omitted from the reply, instead of Unauthorized data is silently omitted from the reply, instead of
dropping the reply or sending an 'access-denied' error. dropping the reply or sending an 'access-denied' error.
Notification Content: Configurable permission to receive specific Notification Content: Configurable permission to receive specific
notification event types is required. notification event types is required.
3.2. 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
should be easy to do simple things, and hard to do complex things, should be easy to do simple things, and hard to do complex things,
instead of hard to do everything. instead of hard to do everything.
Configuration of the access control system must be simple to use. Configuration of the access control system must be simple to use.
Simple and common tasks should be easy to configure, and require Simple and common tasks should be easy to configure, and require
little expertise or domain-specific knowledge. Complex tasks should little expertise or domain-specific knowledge. Complex tasks should
be possible using additional mechanisms which may require additional be possible using additional mechanisms which may require additional
expertise. expertise.
A single set of access control rules should be able to control all A single set of access control rules should be able to control all
types of NETCONF RPC operation invocation, all conceptual database types of NETCONF protocol operation invocation, all conceptual
access, and all NETCONF session output. datastore access, and all NETCONF session output.
Default access control policy needs to be as secure as possible. Default access control policy needs to be as secure as possible.
Protocol access should be defined with a small and familiar set of Protocol access should be defined with a small and familiar set of
permissions, while still allowing full control of NETCONF database permissions, while still allowing full control of NETCONF datastore
access. access.
Access control does not need to be applied to NETCONF <hello> Access control does not need to be applied to NETCONF <hello>
messages. messages.
3.3. Procedural Interface 2.3. Procedural Interface
The NETCONF protocol uses a procedural interface model, and an The NETCONF protocol uses a procedural interface 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 required.
It must be possible to configure the ACM to permit or deny access to It must be possible to configure the ACM to permit or deny access to
specific NETCONF operations. specific NETCONF operations.
YANG modules should be designed so that different access levels for YANG modules should be designed so that different access levels for
input parameters to RPC operations is not required. input parameters to protocol operations is not required.
3.4. Database Access 2.4. Datastore Access
It must be possible control access to specific nodes and sub-trees It must be possible to control access to specific nodes and sub-trees
within the conceptual NETCONF database. within the conceptual NETCONF datastore.
In order for a user to obtain access to a particular database node, In order for a user to obtain access to a particular datastore node,
the user must be authorized to have the same requested access to the the user must be authorized to have the same requested access to the
specified node, and all of its ancestors. specified node, and all of its ancestors.
The same access control rules apply to all conceptual databases. For The same access control rules apply to all conceptual datastores.
example, the candidate configuration or the running configuration. For example, the candidate configuration or the running
configuration.
Only the standard NETCONF databases (candidate, running, and startup) Only the standard NETCONF datastores (candidate, running, and
are controlled by the ACM. Local or remote files or databases startup) are controlled by the ACM. Local or remote files or
accessed via the <url> parameter are optional to support. datastores accessed via the <url> parameter are optional to support.
The non-volatile startup configuration needs to be loaded into the The non-volatile startup configuration needs to be loaded into the
running configuration without applying any access control rules. running configuration without applying any access control rules.
Only a privileged user should be able to alter the factory-default 2.4.1. Access Rights
access control rules.
3.4.1. Access Rights
A small set of hard-wired database access rights is needed to control A small set of hard-wired datastore access rights is needed to
access to all possible NETCONF database operations, including vendor control access to all possible NETCONF datastore operations,
extensions to the standard operation set. including vendor extensions to the standard operation set.
The familiar 'CRUDX' model can support all NETCONF operations: The familiar 'CRUDX' model can support all NETCONF operations:
o Create: Allows the client to add a new data node instance to a o Create: Allows the client to add a new data node instance to a
database. datastore.
o Read: Allows the client to read a data node instance from a o Read: Allows the client to read a data node instance from a
database, or receive the notification event type. datastore, or receive the notification event type.
o Update: Allows the client to update an existing data node instance o Update: Allows the client to update an existing data node instance
in a database. in a datastore.
o Delete: Allows the client to delete a data node instance from a o Delete: Allows the client to delete a data node instance from a
database. datastore.
o eXec: Allows the client to execute the protocol operation. o eXec: Allows the client to execute the protocol operation.
3.4.2. <get> and <get-config> Operations 2.4.2. <get> and <get-config> Operations
Read operations for restricted configuration data, either directly or Data nodes to which the client does not have 'read' access, either
via wildcard access, are silently omitted from the <rpc-reply> directly or via wildcard access, are silently omitted from the <rpc-
message. reply> message.
3.4.3. <edit-config> Operation 2.4.3. <edit-config> Operation
The NACM access rights are not directly coupled to the NETCONF The NACM access rights are not directly coupled to the <edit-config>
operation attribute, although they are similar. Instead, a NACM "operation" attribute, although they are similar. Instead, a NACM
access right applies to all operations which would result in a access right applies to all operations which would result in a
particular access operation to the target database. This section particular access operation to the target datastore. This section
describes how these access rights apply to the specific database describes how these access rights apply to the specific datastore
operations supported by the <edit-config> operation. operations supported by the <edit-config> operation.
If the effective operation is 'none' (i.e., default-operation='none') If the effective operation is 'none' (i.e., default-operation='none')
for a particular data node, then no access control is applied to that for a particular data node, then no access control is applied to that
data node. data node.
A 'create', 'merge', or 'replace' operation on a database node which A 'create', 'merge', or 'replace' operation on a datastore node which
would result in the creation of a new data node instance, for 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 the user does not have 'create' access permission, is rejected with
an 'access-denied' error. an 'access-denied' error.
A 'merge' or 'replace' operation on a database node which would A 'merge' or 'replace' operation on a datastore node which would
result in the modification of an existing data node instance, for result in the modification of an existing data node instance, for
which the user does not have 'update' access permission, is rejected which the user does not have 'update' access permission, is rejected
with an 'access-denied' error. with an 'access-denied' error.
A 'replace' or 'delete' operation on a database node which would A 'replace', 'delete', or 'remove' operation on a datastore node
result in the deletion of an existing data node instance, for which which would result in the deletion of an existing data node instance,
the user does not have 'delete' access permission, is rejected with for which the user does not have 'delete' access permission, is
an 'access-denied' error. rejected with an 'access-denied' error.
A 'merge' operation may include data nodes which do not alter A 'merge' operation may include data nodes which do not alter
portions of the existing database. For example, a container or list portions of the existing datastore. For example, a container or list
nodes may be present for naming purposes, which do not actually alter nodes may be present for naming purposes, which do not actually alter
the corresponding database node. These unaltered data nodes within the corresponding datastore node. These unaltered data nodes within
the scope of a 'merge' operation are ignored by the server, and do the scope of a 'merge' operation are ignored by the server, and do
not require any access rights by the client. not require any access rights by the client.
A 'merge' operation may include data nodes, but not include A 'merge' operation may include data nodes, but not include
particular child data nodes that are present in the database. These particular child data nodes that are present in the datastore. These
missing data nodes within the scope of a 'merge' operation are missing data nodes within the scope of a 'merge' operation are
ignored by the server, and do not require any access rights by the ignored by the server, and do not require any access rights by the
client. client.
The contents of specific restricted database nodes must not be The contents of specific restricted datastore nodes must not be
exposed in any <rpc-error> elements within the reply. exposed in any <rpc-error> elements within the reply.
3.4.4. <copy-config> Operation 2.4.4. <copy-config> Operation
Access control for the <copy-config> operation requires special Access control for the <copy-config> operation requires special
consideration because the operator is replacing the entire target consideration because the operator is replacing the entire target
database. Write access to the entire database is needed for this datastore. Read access to the entire source datastore, and write
operation to succeed. access to the entire target datastore is needed for this operation to
succeed.
A client must have access to every database node, even ones that are A client must have access to every datastore node, even ones that are
not present in the source configuration data. not present in the source configuration data.
For example, consider a common use-case such as a simple backup and For example, consider a common use-case such as a simple backup and
restore procedure. The operator must have full read access to the restore procedure. The operator must have full read access to the
database in order to receive a complete copy of its contents. If datastore in order to receive a complete copy of its contents. If
not, the server will simply omit these sub-trees from the reply. If not, the server will simply omit these sub-trees from the reply. If
that copy is later used to restore the server database, the server that copy is later used to restore the server datastore, the server
will interpret the missing nodes as a request to delete those nodes, will interpret the missing nodes as a request to delete those nodes,
and return an error. and return an error.
3.5. Users and Groups 2.5. Users and Groups
The server must obtain a user name from the underlying NETCONF The server must obtain a user name from the underlying NETCONF
transport, such as an SSH user name. transport, such as an SSH user name.
It must be possible to specify access control rules for a single user It must be possible to specify access control rules for a single user
or a configurable group of users. or a configurable group of users.
A configurable superuser account is needed which bypasses all access A configurable superuser account is needed which bypasses all access
control rules. This is needed in case the access control rules are control rules. This is needed in case the access control rules are
mis-configured, and all access is denied. mis-configured, and all access is denied.
The ACM must support the concept of administrative groups, to support The ACM must support the concept of administrative groups, to support
the well-established distinction between a root account and other the well-established distinction between a root account and other
types of less-privileged conceptual user accounts. These groups must types of less-privileged conceptual user accounts. These groups must
be configurable by the operator. be configurable by the operator.
3.6. Maintenance It must be possible to delegate the user-to-group mapping to a
central server, such as RADIUS [RFC2865] [RFC5607]. Since
authentication is performed by the NETCONF transport layer, and
RADIUS performs authentication and service authorization at the same
time, it must be possible for the underlying NETCONF transport to
report a set of group names associated with the user to the server.
2.6. Maintenance
It should be possible to disable part or all of the access control It should be possible to disable part or all of the access control
model without deleting any configuration. By default, only the model without deleting any configuration. By default, only the
'superuser' should be able to perform this task. 'superuser' should be able to perform this task.
It should be possible to configure a 'superuser' account so that all It should be possible to configure a 'superuser' account so that all
access control is disabled for just this user. This allows the access control is disabled for just this user. This allows the
access control rules to always be modified without completely access control rules to always be modified without completely
disabling access control for all users. disabling access control for all users.
3.7. Configuration Capabilities 2.7. Configuration Capabilities
Suitable control and monitoring mechanisms are needed to allow an Suitable control and monitoring mechanisms are needed to allow an
operator to easily manage all aspects of the ACM behavior. A operator 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>
operation must be available for this purpose. operation must be available for this purpose.
Access control rules to restrict operations on specific sub-trees Access control rules to restrict operations on specific sub-trees
within the configuration database must be supported. Existing within the configuration datastore must be supported. Existing
mechanisms should be used to identify the sub-tree(s) for this mechanisms should be used to identify the sub-tree(s) for this
purpose. purpose.
3.8. Identifying Security Holes 2.8. Identifying Security Holes
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 operations in NETCONF,
not just data and notifications. not just data and notifications.
It is customary 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 operators to study the RFC
and determine if there are any potential security holes introduced and determine if there are any potential security holes introduced
by a new YANG module. by a new YANG module.
o If any security holes are identified, then the operator must study o If any security holes are identified, then the operator must study
some more RFC text, and determine how to close the security some more RFC text, and determine how to close the security
hole(s). hole(s).
skipping to change at page 13, line 40 skipping to change at page 11, line 45
of vulnerability, after the new module is loaded, and before the of vulnerability, after the new module is loaded, and before the
new access control rules for that module are configured, enabled, new access control rules for that module are configured, enabled,
and debugged. and debugged.
Often, the operator just wants to disable default access to the Often, the operator 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 should be able to use machine-readable A data model designer should be able to use machine-readable
statements to identity NETCONF content which should be protected by statements to identify NETCONF content which should 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 close data-model specific security holes, 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 operation.
3.9. Data Shadowing 2.9. Data Shadowing
One of the more complicated security administration problems is One of the more complicated security administration problems is
identifying data nodes which shadow or mirror the content of another identifying data nodes which shadow or mirror the content of another
data node. An access control rule to prevent read operations for a data node. An access control rule to prevent read operations for a
particular node may be insufficient to prevent access to the data particular node may be insufficient to prevent access to the data
node with the copied value. node with the copied value.
If the YANG leafref data type is used, then this data shadowing can If the YANG leafref data type is used, then this data shadowing can
be detected by applications (and the server stack), and prevented. be detected by applications (and the server stack), and prevented.
If the description statement, other documentation, or no If the description statement, other documentation, or no
documentation exists to identify a data shadow problem, then it may documentation exists to identify a data shadow problem, then it may
not be detected. not be detected.
Since NETCONF allows any vendor operation to be added to the Since NETCONF allows any vendor operation to be added to the
protocol, there is no way to reliably identify all of the operations protocol, there is no way to reliably identify all of the operations
that may expose copies of sensitive data nodes in <rpc-reply> that may expose copies of sensitive data nodes in <rpc-reply>
messages. messages.
A NETCONF server must insure than unauthorized access to its A NETCONF server must ensure that unauthorized access to its
conceptual databases and non-configuration data nodes is prevented. conceptual datastores and non-configuration data nodes is prevented.
It is beyond the scope of this document to define access control It is beyond the scope of this document to define access control
enforcement procedures for underlying device instrumentation that may enforcement procedures for underlying device instrumentation that may
exist to support the NETCONF server operation. An operator must exist to support the NETCONF server operation. An operator must
identify each operation that the server provides, and decide if it identify each operation that the server provides, and decide if it
needs any access control applied to it. needs any access control applied to it.
Proprietary protocol operations should be properly documented by the Proprietary protocol operations should be properly documented by the
vendor, so it is clear to operators what data nodes (if any) are vendor, so it is clear to operators what data nodes (if any) are
affected by the operation, and what information (if any) is returned affected by the operation, and what information (if any) is returned
in the <rpc-reply> message. in the <rpc-reply> message.
3.10. NETCONF Specific Requirements 2.10. NETCONF Specific Requirements
The server must be able to identify the specific protocol access The server MUST be able to identify the specific protocol access
request at the 4 access control points defined above. request at the 4 access control points defined above.
The server must be able to identify any database access request, even The server MUST be able to identify any datastore access request,
for proprietary operations. even for proprietary operations.
A session must always be authorized to invoke the <close-session> A client MUST always be authorized to invoke the <close-session>
operation, defined in [RFC4741]. operation, defined in [I-D.ietf-netconf-4741bis].
A session must always be authorized to receive the <replayComplete> A client MUST always be authorized to receive the <replayComplete>
and <notificationComplete> notification events, defined in [RFC5277] and <notificationComplete> notification events, defined in [RFC5277]
The set of module name strings used within one particular server MUST
The set of module name strings used within one particular server must
be unique. be unique.
Within a single server, the module namespace URI associated with a 3. NETCONF Access Control Model (NACM)
specific module name string must persist across a reboot, and never
change, once assigned.
4. NETCONF Authentication and Authorization Model
This document defines three authentication methods for use with
NETCONF:
publickey for local users over SSH
password for local users over any transport
password for RADIUS users over any transport
Additional methods may be defined by other standard documents or by
vendors.
Conceptually, the NETCONF transport subsystem authenticates the user,
and passes the name of the authenticated user to the NETCONF server.
The NETCONF server authorizes the user by mapping it to one or more
groups. Access to specific operations and content is then controlled
by access control rules as described in Section 5.
Some protocols, such as RADIUS, performs both authentication and
authorization, and has a mechanism to report authorization attributes
to the client. These attributes are made available to the NETCONF
server in an implementation specific manner.
This document defines two optional YANG features, 'local-users' and
'radius', which the server advertises to indicate support for
configuring local users on the device, and for configuring RADIUS
access, respectively.
4.1. SSH Public Key Authentication
If the NETCONF server advertises the 'local-users' feature,
configuration of local users and their SSH public keys is supported
in the /nacm/authentication/user list.
Public key authentication is requested by the SSH client. The SSH
server looks up the user name provided by the client in the /nacm/
authentication/user list, and verifies the key as described in
[RFC4253].
If the 'local-users' feature is supported, then when a NETCONF client
starts an SSH session towards the server, using the "publickey"
authentication 'method name' [RFC4252], the SSH server looks up the
user name given in the SSH authentication request in the /nacm/
authentication/user list,
4.2. Local User Password Authentication
If the NETCONF server advertises the 'local-users' feature,
configuration of local users and their passwords is supported in the
/nacm/authentication/user list.
For NETCONF transport protocols that support password authentication,
the leaf-list 'user-authentication-order' is used to control if local
user password authentication should be used.
In SSH, password authentication is requested by the client. Other
NETCONF transport protocols may also support password authentication.
When local user password authentication is requested, the NETCONF
transport looks up the user name provided by the client in the /nacm/
authentication/user list, and verifies the password.
4.3. RADIUS Password Authentication and Service Authorization
If the NETCONF server advertises the 'radius' feature, it supports
user authentication and service authorization with RADIUS, as
described in this section.
For NETCONF transport protocols that support password authentication,
the leaf-list 'user-authentication-order' is used to control if
RADIUS password authentication should be used.
In SSH, password authentication is requested by the client. Other
NETCONF transport protocols may also support password authentication.
4.3.1. Operation
[Editor's Note: I prefer to keep this section short, and just refer
to the relevant rfcs which have detailed information on radius usage,
instead of duplicating this info here...]
When RADIUS user authentication is requested, the NETCONF transport
subsystem acts as a RADIUS client. In the Access-Request request
[RFC2865], the following RADIUS attributes SHOULD be sent by the
client [RFC5607]:
o Service-Type with the value Framed-Management
o Framed-Management-Protocol with the value NETCONF
o Management-Transport-Protection with the value Integrity-
Confidentiality-Protection
As described in RFC 5607, if an Access-Accept message is received
which does not authorize the requested service, access MUST be
denied.
If any Management-Policy-Id attributes are present in the Access-
Accept message, they are treated as group names in the access control
procedure, as described in Section 5.
The following RADIUS attributes MAY be sent by the RADIUS server:
o Session-Timeout
o Idle-Timeout
See [RFC2865] for a description of these attributes. These timeout
values MUST be enforced by the NETCONF server.
5. NETCONF Access Control Model (NACM)
5.1. 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.
5.1.1. Features 3.1.1. Features
The NACM data model provides the following features: The NACM data model provides the following features:
o Independent control of RPC, data, and notification access. o Independent control of RPC, data, and notification access.
o Very simple access control rules configuration data model which is o Very simple access control rules configuration data model which is
easy to use. easy to use.
o The concept of a 'superuser' type of account is supported, but o The concept of a 'superuser' type of account is supported, but
configuration such an account is beyond the scope of this configuration such an account is beyond the scope of this
document. The server must be able to determine if a superuser document. The server must be able to determine if a superuser
account is available, and if so, the actual user name for this account is available, and if so, the actual user name for this
account. A session associated with the superuser account will account. A session associated with the superuser account will
bypass all access control enforcement. bypass all access control enforcement.
o A simple and familiar set of database 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:secure extension)
allows default security modes to automatically exclude sensitive allows default security modes to automatically exclude sensitive
data. 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 RPC operation requests and denied database o The number of denied protocol operation requests and denied
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, or child configure access control rules for specific data nodes.
nodes within specific RPC input, RPC output, and notification
event type content.
5.1.2. External Dependencies 3.1.2. External Dependencies
The NETCONF [RFC4741] protocol is used for all management purposes The NETCONF [I-D.ietf-netconf-4741bis] protocol is used for all
within this document. The server must support the features management purposes within this document. It is expected that the
identified by the 'NETCONF-base' capability. It is expected that the mandatory transport mapping NETCONF Over SSH
mandatory transport mapping NETCONF Over SSH [RFC4742] is also [I-D.ietf-netconf-rfc4742bis] is also supported by the server, and
supported by the server, and that the server has access to the user that the server has access to the user name associated with each
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. The YANG instance- NETCONF data models specified in this document. The YANG instance-
identifier data type can be used to configure data-node-specific identifier data type is used to configure data-node-specific access
access control rules. control rules.
5.1.3. Message Processing Model 3.1.3. Message Processing Model
The following diagram shows the NETCONF message flow model, including The following diagram shows the NETCONF message flow model, including
the points at which access control is applied, during NETCONF message the points at which access control is applied, during NETCONF message
processing. processing.
+-------------------------+ +-------------------------+
| session | | session |
| (username) | | (username) |
+-------------------------+ +-------------------------+
| ^ | ^
skipping to change at page 20, line 37 skipping to change at page 16, line 37
| | ^ ^ | | ^ ^
V +----------------+ | | V +----------------+ | |
+===========+ | | | +===========+ | | |
| data node | | | | | data node | | | |
| acc. ctl | -----------+ | | | | acc. ctl | -----------+ | | |
+===========+ | | | | +===========+ | | | |
| | | | | | | | | |
V V V | | V V V | |
+---------------+ +-----------------+ +---------------+ +-----------------+
| configuration | ---> | server | | configuration | ---> | server |
| database | | instrumentation | | datastore | | instrumentation |
| | <--- | | | | <--- | |
+---------------+ +-----------------+ +---------------+ +-----------------+
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 user identity for the session is the session, unless the session is associated with the 'superuser'
'superuser'. account.
o If the session is authorized to execute the specified RPC o If the session is authorized to execute the specified RPC
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 database or conceptual state data is accessed o If the configuration datastore or conceptual state data is
by the RPC operation, then the configuration access must be accessed by the protocol operation, then the data node access must
authorized first. If the session is authorized to perform the be authorized. If the session is authorized to perform the
requested operation on the requested data, then processing requested 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 conceptual notification, for a
particular subscription. particular 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 session is not authorized
to read, then the notification is dropped for that subscription. to read, then the notification is dropped for that subscription.
5.2. Model Components 3.2. Model Components
This section defines the conceptual components related to access This section defines the conceptual components related to access
control model. control model.
5.2.1. Users 3.2.1. Users
A 'user' is the conceptual identity, which is associated with the A 'user' is the conceptual entity, which is associated with the
access permissions granted to a particular session. A user is access permissions granted to a particular session. A user is
identified by a string which must be unique within the server. identified by a string which must be unique within the server.
The user name string is usually derived from the transport layer As described in [I-D.ietf-netconf-4741bis], the user name string is
during session establishment. A server is required to have an derived from the transport layer during session establishment. If
authenticated user name for a session before <rpc> requests will be the transport layer cannot authenticate the user, the session is
accepted. Otherwise all write requests must be rejected with an terminated.
'access-denied' error-tag value. If a read operation is not
authorized, then the requested data is silently dropped from the
reply.
The server MAY support a 'superuser' administrative user account, The server MAY support a 'superuser' administrative user account,
which will bypass all access control enforcement. This is useful for which will bypass all access control enforcement. This is useful for
restricting initial access and repairing a broken access control restricting initial access and repairing a broken access control
configuration. This account may be configurable to use a specific configuration. This account may be configurable to use a specific
user, or disabled completely. Some systems have factory-selected user, or disabled completely. Some systems have factory-selected
superuser account names. There is no need to standardize the exact superuser account names. There is no need to standardize the exact
user name for the superuser account. If no such account exists, then user name for the superuser account. If no such account exists, then
all NETCONF access will be controlled by NACM. all NETCONF access will be controlled by NACM.
5.2.2. Groups 3.2.2. Groups
Access to a specific NETCONF operation is granted to a session, Access to a specific NETCONF operation is granted to a session,
associated with a group, not a user. associated with a group, not a user.
A group is identified by its name. All group names must be unique A group is identified by its name. All group names must be unique
within the server. within the server.
A group member is identified by a user name string. A group member is identified by a user name string.
The same user may be configured in multiple groups. The same user may be configured in multiple groups.
The server should support the 3 default group identities defined in 3.2.3. Sessions
this document (admin, monitor, guest), however these roles are just
unique identities, provided for operator convenience. There is no
standard behavior defined for each group identity. That is up to the
operator who configures the groups.
5.2.3. Sessions
A session is simply a NETCONF session, which is the entity which is A session is simply a NETCONF session, which is the entity which is
granted access to specific NETCONF operations. granted access to specific NETCONF operations.
A session is associated with a single user name for the lifetime of A session is associated with a single user name for the lifetime of
the session. the session.
5.2.4. Access Permissions 3.2.4. Access Permissions
The access permissions are the NETCONF protocol specific set of The access permissions are the NETCONF protocol specific set of
permissions that have been assigned to a particular session role or permissions that have been assigned to a particular session.
group.
The same access permissions MUST stay in effect for the processing of The same access permissions MUST stay in effect for the processing of
a particular message. a particular message.
The server MUST use the access control rules in effect at the time The server MUST use the access control rules in effect at the time
the message is processed. the message is processed.
The access control model treats RPC operation execution separately The access control model treats protocol operation execution
from configuration database access and outgoing messages: separately from configuration datastore access and outgoing messages:
create: Permission to create conceptual server data. create: Permission to create conceptual server data.
read: Read access to conceptual server data, <rpc-reply> and read: Read access to conceptual server data, <rpc-reply> and
<notification> content. <notification> content.
update: Permission to modify existing conceptual server data. update: Permission to modify existing conceptual server data.
delete: Permission to delete existing conceptual server data. delete: Permission to delete existing conceptual server data.
exec: Permission to invoke an RPC operation. exec: Permission to invoke an protocol operation.
5.2.5. Global Enforcement Controls 3.2.5. Global Enforcement Controls
A global on/off switch is provided to enable or disable all access A global on/off switch is provided to enable or disable all access
control enforcement. control enforcement.
An on/off switch is provided to enable or disable default access to An on/off switch is provided to enable or disable default access to
invoke RPC operations. invoke protocol operations.
An on/off switch is provided to enable or disable default permission An on/off switch is provided to enable or disable default permission
to receive data in replies and notifications. to receive data in replies and notifications.
An on/off switch is provided to enable or disable default access to An on/off switch is provided to enable or disable default access to
alter configuration data. alter configuration data.
5.2.6. Access Control Rules 3.2.6. 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 module,
identified by its name. identified by its name.
RPC operation rule: Controls access for a specific RPC operation, protocol operation rule: Controls access for a specific protocol
identified by its module and name. operation, identified by its 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 module and name.
5.3. Access Control Enforcement Procedures 3.3. Access Control Enforcement Procedures
There are seven separate phases that must be addressed, four of which There are seven separate phases that must be addressed, four of which
are related to the NETCONF message processing model. In addition, are related to the NETCONF message processing model. In addition,
the initial start-up mode for a NETCONF server, session the initial start-up mode for a NETCONF server, session
establishment, and 'access-denied' error handling procedures must establishment, and 'access-denied' error handling procedures must
also be considered. also be considered.
5.3.1. Initial Operation 3.3.1. 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 not, a server control configuration will probably not be present. If not, a server
should not allow any write access to any session role except MUST NOT allow any write access to any session role except
'superuser' type of account in this state. 'superuser' type of account in this state.
There is no requirement to enforce access control rules before or There is no requirement to enforce access control rules before or
while the non-volatile configuration data is processed and loaded while the non-volatile configuration data is processed and loaded
into the running configuration. into the running configuration.
5.3.2. Session Establishment 3.3.2. 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 A server should not include any sensitive information in any
<capability> elements within the <hello> exchange. <capability> elements within the <hello> exchange.
Once session establishment is completed, and a user identity has been Once session establishment is completed, and a user identity has been
authenticated, a NETCONF server will enforce the access control authenticated, the NETCONF transport layer reports the username and a
rules, based on the supplied user identity and the configuration data possibly empty set of group names associated with the user to the
stored on the server. NETCONF server. The NETCONF server will enforce the access control
rules, based on the supplied user identity, group names, and the
configuration data stored on the server.
5.3.3. 'access-denied' Error Handling 3.3.3. '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 an RPC operation system denies access to either a request to invoke a protocol
or a request to perform a particular operation on the configuration operation or a request to perform a particular operation on the
database. 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.
5.3.4. Incoming RPC Message Validation 3.3.4. 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 25, line 32 skipping to change at page 21, line 32
+-----------+ +---------------+ +------------+ +-----------+ +---------------+ +------------+
| acme NS | | NC-base NS | | NC-base NS | | acme NS | | NC-base NS | | NC-base NS |
| <my-edit> | | <edit-config> | | <unlock> | | <my-edit> | | <edit-config> | | <unlock> |
+-----------+ +---------------+ +------------+ +-----------+ +---------------+ +------------+
| | | |
| | | |
V V V V
+----------------------+ +----------------------+
| | | |
| configuration | | configuration |
| database | | datastore |
+----------------------+ +----------------------+
Figure 3 Figure 3
Access control begins with the message dispatcher. Only well-formed Access control begins with the message dispatcher. Only well-formed
XML messages should be processed by the server. XML messages should be processed by the server.
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 RPC 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 RPC access control enforcer verifies that the session
is authorized to invoke the RPC operation. is authorized to invoke the protocol operation.
The RPC operation is authorized by following these steps: The protocol operation is authorized by following these steps:
1. If the <enable-nacm> parameter is set to 'false', then the RPC 1. If the <enable-nacm> parameter is set to 'false', then the
operation is permitted. protocol operation is permitted.
2. If the session is associated with the 'superuser' account, then 2. If the session is associated with the 'superuser' account, then
the RPC operation is permitted. 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 RPC operation is permitted. 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 matches the user name for the session making name> entry that matches the user name for the session making
the request. the request. Add to these groups the set of groups provided by
the transport layer.
5. If no groups are found: 5. If no groups are found:
* If the requested RPC operation is associated with a YANG * If the requested protocol operation is associated with a YANG
module advertised in the server capabilities, and the rpc module advertised in the server capabilities, and the rpc
statement contains a nacm:secure or nacm:very-secure statement contains a nacm:secure or nacm:very-secure
extension, then the RPC operation is denied. extension, then the protocol operation is denied.
* If the <exec-default> parameter is set to 'permit', then * If the <exec-default> parameter is set to 'permit', then
permit the RPC operation, otherwise deny the request. permit the protocol operation, otherwise deny the request.
6. Check if there are any matching <rpc-rule> entries for the 6. Check if there are any matching <rpc-rule> entries for the
requested RPC operation. Any matching rules are processed in requested protocol operation. Any matching rules are processed
user-defined order, in case there are multiple <rpc-rule> in user-defined order, in case there are multiple <rpc-rule>
entries for the requested RPC operation. entries for the requested protocol operation.
7. If an <rpc-rule> entry is found, then check the <allowed-rights> 7. If an <rpc-rule> entry is found, then check the <allowed-rights>
bits field for the entry, otherwise continue. The 'exec' bit bits field for the entry, otherwise continue. The 'exec' bit
MUST be present in the <allowed-rights> bits field for an <rpc- MUST be present in the <allowed-rights> bits field for an <rpc-
rule>, so it is not used in this procedure. rule>, so it is not used in this procedure.
8. If the <rpc-rule> entry is considered a match, the the 'nacm- 8. If the <rpc-rule> entry is considered a match, then the 'nacm-
action' leaf is checked. If is equal to 'permit', then the RPC action' leaf is checked. If is equal to 'permit', then the
operation is permitted, otherwise it is denied. protocol operation is permitted, otherwise it is denied.
9. Check if there are any matching <module-rule> entries for the 9. Check if there are any matching <module-rule> entries for the
same module as the requested RPC operation. Any matching rules same module as the requested protocol operation. Any matching
are processed in user-defined order, in case there are multiple rules are processed in user-defined order, in case there are
<module-rule> entries for the module containing the requested multiple <module-rule> entries for the module containing the
RPC operation. requested protocol operation.
10. If a <module-rule> entry is found, then check the <allowed- 10. If a <module-rule> entry is found, then check the <allowed-
rights> bits field for the entry, otherwise continue. If the rights> bits field for the entry, otherwise continue. If the
'exec' bit is present in the <allowed-rights> bits field then 'exec' bit is present in the <allowed-rights> bits field then
the RPC rule is considered a match. otherwise it is not the RPC rule is considered a match. otherwise it is not
considered to match the request. considered to match the request.
11. If the <module-rule> entry is considered a match, the the 'nacm- 11. If the <module-rule> entry is considered a match, then the
action' leaf is checked. If is equal to 'permit', then the RPC 'nacm-action' leaf is checked. If is equal to 'permit', then
operation is permitted, otherwise it is denied. the protocol operation is permitted, otherwise it is denied.
12. If the requested operation is identified an a nacm:secure or 12. If the requested operation is identified an a nacm:secure or
nacm:very-secure RPC operation, then the RPC operation is nacm:very-secure protocol operation, then the protocol operation
denied. is denied.
13. If the <exec-default> parameter is set to 'permit', then permit 13. If the <exec-default> parameter is set to 'permit', then permit
the RPC operation, otherwise the RPC operation is denied. the protocol operation, otherwise the protocol operation is
denied.
If the session is not authorized to invoke the RPC operation then an If the session is not authorized to invoke the protocol operation
<rpc-error> is generated with the following information: then an <rpc-error> is generated with the following information:
error-tag: access-denied error-tag: access-denied
error-path: /rpc/method-QName, where 'method-QName' is a qualified error-path: /rpc/method-QName, where 'method-QName' is a qualified
name identifying the actual RPC operation name. For example, name identifying the actual protocol operation name. For example,
'/rpc/edit-config' represents the <edit-config> operation in the '/rpc/edit-config' represents the <edit-config> operation in the
NETCONF base namespace. NETCONF base namespace.
If the configuration database is accessed, either directly or as a If the configuration datastore is accessed, either directly or as a
side effect of the RPC operation, then the server must intercept the side effect of the protocol operation, then the server MUST intercept
operation and make sure the session is authorized to perform the the operation and make sure the session is authorized to perform the
requested operation on the specified data. requested operation on the specified data.
5.3.5. Data Node Access Validation 3.3.5. Data Node Access Validation
If a data node within a configuration database is accessed, or a If a data node within a configuration datastore is accessed, or a
conceptual non-configuration node is accessed, then the server must conceptual non-configuration node is accessed, then the server MUST
ensure that the client session is authorized to perform the requested ensure that the client session is authorized to perform the requested
operation create, read, update, or delete operation on the specified operation create, read, update, or delete operation on the specified
data node. 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> parameter is set to 'false', then the data 1. If the <enable-nacm> parameter is set to 'false', then the data
node access request is permitted. node access request is permitted.
2. If the session is associated with the 'superuser' account, then 2. If the session is associated with the 'superuser' account, then
the data node access request is permitted. the data node access request 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 matches the user name for the session making name> entry that matches the user name for the session making
the request. the request. Add to these groups the set of groups provided by
the transport layer.
4. If no groups are found: 4. If no groups are found:
* If the requested data node is associated with a YANG module * If the requested data node is associated with a YANG module
advertised in the server capabilities, and the data advertised in the server capabilities, and the data
definition statements (or any of its ancestors) contains a definition statement or any of its ancestors contains a nacm:
nacm:secure or nacm:very-secure extension, then the data node secure or nacm:very-secure extension, then the data node
access request is denied. access request is denied.
* For a read request, if the <read-default> parameter is set to * For a read request, if the <read-default> parameter is set to
'permit', then permit the data node access request, otherwise 'permit', then permit the data node access request, otherwise
deny the request. For a read operation, this means that the deny the request. For a read operation, this means that the
requested node is not included in the rpc-reply. requested node is not included in the rpc-reply.
* For a write request, if the <write-default> parameter is set * For a write request, if the <write-default> parameter is set
to 'permit', then permit the data node access request, to 'permit', then permit the data node access request,
otherwise deny the request. otherwise deny the request.
skipping to change at page 28, line 41 skipping to change at page 24, line 46
be a match. be a match.
3. For an update (e.g., 'merge' or 'replace') operation, if the 3. For an update (e.g., 'merge' or 'replace') operation, if the
'update' bit is present in the <allowed-rights> bits field 'update' bit is present in the <allowed-rights> bits field
then the entry is considered to be a match. then the entry is considered to be a match.
4. For a deletion (e.g., 'delete') operation, if the 'delete' 4. For a deletion (e.g., 'delete') operation, if the 'delete'
bit is present in the <allowed-rights> bits field then the bit is present in the <allowed-rights> bits field then the
entry is considered to be a match. entry is considered to be a match.
7. If the <data-rule> entry is considered a match, the the 'nacm- 7. If the <data-rule> entry is considered a match, then the 'nacm-
action' leaf is checked. If it is equal to 'permit', then the action' leaf is checked. If it is equal to 'permit', then the
data operation is permitted, otherwise it is denied. For 'read' data operation is permitted, otherwise it is denied. For 'read'
operations, 'denied' means the requested data is not returned in operations, 'denied' means the requested data is not returned in
the reply. the reply.
8. Check if there are any matching <module-rule> entries for the 8. Check if there are any matching <module-rule> entries for the
same module as the requested data node. Any matching rules are same module as the requested data node. Any matching rules are
processed in user-defined order, in case there are multiple processed in user-defined order, in case there are multiple
<module-rule> entries for the module containing the requested <module-rule> entries for the module containing the requested
data node. data node.
skipping to change at page 29, line 24 skipping to change at page 25, line 30
be a match. be a match.
3. For an update (e.g., 'merge' or 'replace') operation, if the 3. For an update (e.g., 'merge' or 'replace') operation, if the
'update' bit is present in the <allowed-rights> bits field 'update' bit is present in the <allowed-rights> bits field
then the entry is considered to be a match. then the entry is considered to be a match.
4. For a deletion (e.g., 'delete') operation, if the 'delete' 4. For a deletion (e.g., 'delete') operation, if the 'delete'
bit is present in the <allowed-rights> bits field then the bit is present in the <allowed-rights> bits field then the
entry is considered to be a match. entry is considered to be a match.
10. If the <module-rule> entry is considered a match, the the 'nacm- 10. If the <module-rule> entry is considered a match, then the
action' leaf is checked. If it is equal to 'permit', then the 'nacm-action' leaf is checked. If it is equal to 'permit', then
data operation is permitted, otherwise it is denied. For 'read' the data operation is permitted, otherwise it is denied. For
operations, 'denied' means the requested data is not returned in 'read' operations, 'denied' means the requested data is not
the reply. returned in the reply.
11. For a read request, if the requested data node is identified an 11. For a read request, if the requested data node is identified an
a nacm:very-secure definition, then the requested data node is a nacm:very-secure definition, then the requested data node is
not included in the reply. not included in the reply.
12. For a write request, if the requested data node is identified an 12. For a write request, if the requested data node is identified an
a nacm:secure or nacm:very-secure definition, then the data node a nacm:secure or nacm:very-secure definition, then the data node
access request is denied. access request is denied.
13. For a read request, if the <read-default> parameter is set to 13. For a read request, if the <read-default> parameter is set to
'permit', then include the requested data in the reply, 'permit', then include the requested data in the reply,
otherwise do not inlcude the requested data in the reply. otherwise do not include the requested data in the reply.
14. For a write request, if the <write-default> parameter is set to 14. For a write request, if the <write-default> parameter is set to
'permit', then permit the data node access request, otherwise 'permit', then permit the data node access request, otherwise
deny the request. deny the request.
5.3.6. Outgoing <rpc-reply> Authorization 3.3.6. Outgoing <rpc-reply> Authorization
The <rpc-reply> message should be checked by the server to make sure The <rpc-reply> message should be checked by the server to make sure
no unauthorized data is contained within it. If so, the restricted no unauthorized data is contained within it. If so, the restricted
data must be removed from the message before it is sent to the data must be removed from the message before it is sent to the
client. client.
For RPC operations which do not access any data nodes, then any For protocol operations which do not access any data nodes, then any
client authorized to invoke the RPC operation is also authorized to client authorized to invoke the protocol operation is also authorized
receive the <rpc-reply> for that RPC operation. to receive the <rpc-reply> for that protocol operation.
5.3.7. Outgoing <notification> Authorization 3.3.7. Outgoing <notification> Authorization
The <notification> message should be checked by the server to make The <notification> message should be checked by the server to make
sure no unauthorized data is contained within it. If so, the sure no unauthorized data is contained within it. If so, the
restricted data must be removed from the message before it is sent to restricted data must be removed from the message before it is sent to
the client. the client.
Configuration of access control rules specifically for descendent Configuration of access control rules specifically for descendent
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 session is authorized to receive the
notification event type, then it is also authorized to receive any notification event type, then it is also authorized to receive any
skipping to change at page 31, line 33 skipping to change at page 27, line 33
+=================+ +=================+
^ ^
| |
+------------------------+ +------------------------+
| server instrumentation | | server instrumentation |
+------------------------+ +------------------------+
| ^ | ^
V | V |
+----------------------+ +----------------------+
| configuration | | configuration |
| database | | datastore |
+----------------------+ +----------------------+
Figure 4 Figure 4
The generation of a notification event for a specific subscription is The generation of a notification event for a specific subscription is
authorized by following these steps: authorized by following these steps:
1. If the <enable-nacm> parameter is set to 'false', then the 1. If the <enable-nacm> parameter is set to 'false', then the
notification event is permitted. notification event is permitted.
2. If the session is associated with the 'superuser' account, then 2. If the session is associated with the 'superuser' account, then
the notification event is permitted. the notification event is permitted.
3. If the requested operation is the NETCONF <replayComplete> or 3. If the requested operation is the NETCONF <replayComplete> or
<notificationComplete> event type, then the notification event <notificationComplete> event type, then the notification event
is permitted. 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 matches the user name for the session that name> entry that matches the user name for the session that
started the notification subscription. started the notification subscription. Add to these groups the
set of groups provided by the transport layer.
5. If no groups are found: 5. If no groups are found:
* If the requested notification is associated with a YANG * If the requested notification is associated with a YANG
module advertised in the server capabilities, and the module advertised in the server capabilities, and the
notification statement contains a nacm:secure or nacm:very- notification statement contains a nacm:secure or nacm:very-
secure extension, then the notification event is dropped for secure extension, then the notification event is dropped for
the associated subscription. the associated subscription.
* If the <read-default> parameter is set to 'permit', then * If the <read-default> parameter is set to 'permit', then
skipping to change at page 33, line 5 skipping to change at page 29, line 5
dropped for the associated subscription. dropped for the associated subscription.
10. If the requested event type is identified an a nacm:very-secure 10. If the requested event type is identified an a nacm:very-secure
notification definition, then the notification event type is notification definition, then the notification event type is
denied. denied.
11. If the <read-default> parameter is set to 'permit', then permit 11. If the <read-default> parameter is set to 'permit', then permit
the notification event type, otherwise it is dropped for the the notification event type, otherwise it is dropped for the
associated subscription. associated subscription.
5.4. Data Model Definitions 3.4. 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 5.4. found in the data model in Section 3.4.
5.4.1. High Level Procedures 3.4.1. High Level Procedures
There are some high level management procedures that an administrator There are some high level management procedures that an administrator
needs to consider before using this access control model: needs to consider before using this access control model:
1. Configure the global settings. 1. Configure the global settings.
2. Configure one or more user groups. 2. Configure one or more user groups.
3. Configure zero or more access control rules for specific modules. 3. Configure zero or more access control rules for specific modules.
4. Configure zero or more access control rules for specific RPC 4. Configure zero or more access control rules for specific protocol
operations. operations.
5. Configure zero or more access control rules for data node access. 5. Configure zero or more access control rules for data node access.
6. Configure zero or more access control rules for notification 6. Configure zero or more access control rules for notification
event type access. event type access.
5.4.2. Data Organization 3.4.2. Data Organization
The top-level element is called <nacm>, and it is defined in the The top-level element is called <nacm>, and it is defined in the
'nacm' module namespace. 'ietf-netconf-acm' module namespace.
There are several data structures defined as child nodes of the There are several data structures defined as child nodes of the
<nacm> element: <nacm> element:
leaf <enable-nacm>: On/off boolean switch to enable or disable leaf <enable-nacm>: On/off boolean switch to enable or disable
access control enforcement. access control enforcement.
container <authentication>: Configuration of the NETCONF server user
authentication mechanisms.
leaf <read-default>: Enumeration to permit or deny default read leaf <read-default>: Enumeration to permit or deny default read
access requests. access requests.
leaf <write-default>: Enumeration to permit or deny default write leaf <write-default>: Enumeration to permit or deny default write
access requests. access requests.
leaf <exec-default>: Enumeration to permit or deny default RPC leaf <exec-default>: Enumeration to permit or deny default protocol
operation execution requests. operation execution requests.
leaf <denied-rpcs>: Read-only counter of the number of times the leaf <denied-rpcs>: Read-only counter of the number of times the
server has denied an RPC operation request, since the last reboot server has denied an RPC operation request, since the last reboot
of the server. of the server.
leaf <denied-data-writes>: Read-only counter of the number of times leaf <denied-data-writes>: Read-only counter of the number of times
the server has denied a data node write request, since the last the server has denied a data node write request, since the last
reboot of the server. reboot of the server.
skipping to change at page 34, line 25 skipping to change at page 30, line 21
list <group>: A list of user names belonging to the same list <group>: A list of user names belonging to the same
administrative group. administrative group.
container <rules>: Configures the access control rules used within container <rules>: Configures the access control rules used within
the server. the server.
list <module-rule>: Configures the access control rules for a list <module-rule>: Configures the access control rules for a
specific module. specific module.
list <rpc-rule>: Configures the access control rules for RPC list <rpc-rule>: Configures the access control rules for protocol
operation invocation. operation invocation.
list <data-rule>: Configures the access control rules for list <data-rule>: Configures the access control rules for
configuration database access. configuration datastore access.
list <notification-rule>: Configures the access control rules for list <notification-rule>: Configures the access control rules for
controlling delivery of <notification> events. controlling delivery of <notification> events.
5.4.3. YANG Module 3.4.3. YANG Module
The following YANG module is provided to specify the normative The following YANG module is provided to specify the normative
NETCONF content that must by supported by the server. NETCONF content that must by supported by the server.
The ietf-nacm 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-nacm@2010-10-25.yang"
module ietf-nacm {
namespace "urn:ietf:params:xml:ns:yang:ietf-nacm";
prefix "nacm";
import ietf-yang-types {
prefix yang;
}
import ietf-inet-types {
prefix inet;
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue // RFC Ed.: please update the date to the date of publication
<mailto:mehmet.ersue@nsn.com> <CODE BEGINS> file="ietf-netconf-acm@2011-02-03.yang"
WG Chair: Bert Wijnen module ietf-netconf-acm {
<mailto:bertietf@bwijnen.net>
Editor: Andy Bierman namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-acm";
<mailto:andy.bierman@brocade.com>
Editor: Martin Bjorklund prefix "nacm";
<mailto:mbj@tail-f.com>";
description import ietf-yang-types {
"NETCONF Server Access Control Model. prefix yang;
}
Copyright (c) 2010 IETF Trust and the persons identified as organization
authors of the code. All rights reserved. "IETF NETCONF (Network Configuration) Working Group";
Redistribution and use in source and binary forms, with or contact
without modification, is permitted pursuant to, and subject "WG Web: <http://tools.ietf.org/wg/netconf/>
to the license terms contained in, the Simplified BSD WG List: <mailto:netconf@ietf.org>
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 XXX; see WG Chair: Mehmet Ersue
the RFC itself for full legal notices."; <mailto:mehmet.ersue@nsn.com>
// RFC Ed.: replace XXXX with actual RFC number and remove this note
//reference "RFC XXXX"; WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net>
// RFC Ed.: remove this note Editor: Andy Bierman
// Note: extracted from draft-ietf-netconf-access-control-01.txt <mailto:andy.bierman@brocade.com>
// RFC Ed.: please update the date to the date of publication
revision "2010-10-25" {
description
"Initial version";
reference
"RFC XXXX: Network Configuration Protocol Access Control Model";
}
/* Editor: Martin Bjorklund
* Extension statements <mailto:mbj@tail-f.com>";
*/
extension secure {
description description
"Used to indicate that the data model node "NETCONF Server Access Control Model.
represents a sensitive security system parameter.
If present, the NETCONF server will only allow
the designated 'superuser' to have write or execute
default nacm-rights-type for the node. An explicit access
control rule is required for all other users.
The 'secure' extension may appear within a data, rpc, Copyright (c) 2011 IETF Trust and the persons identified as
or notification node definition. It is ignored authors of the code. All rights reserved.
otherwise.";
}
extension very-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
controls a very 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, the NETCONF server will only allow This version of this YANG module is part of RFC XXXX; see
the designated 'superuser' to have read, write, or execute the RFC itself for full legal notices.";
default nacm-rights-type for the node. An explicit access // RFC Ed.: replace XXXX with actual RFC number and
control rule is required for all other users. // remove this note
The 'very-secure' extension may appear within a data, rpc, // RFC Ed.: remove this note
or notification node definition. It is ignored // Note: extracted from draft-ietf-netconf-access-control-02.txt
otherwise.";
}
/* // RFC Ed.: please update the date to the date of publication
* Features revision "2011-02-03" {
*/ description
"Initial version";
reference
"RFC XXXX: Network Configuration Protocol
Access Control Model";
}
feature authentication { /*
description * Extension statements
"Indicates that the NETCONF server can be configured */
to do authentication of users.";
}
feature radius { extension secure {
if-feature authentication; description
description "Used to indicate that the data model node
"Indicates that the NETCONF server can be represents a sensitive security system parameter.
configured to act as a NAS and authenticate users
with RADIUS.";
reference
"RFC 2865: Remote Authentication Dial In User Service (RADIUS)
RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
Authorization for Network Access Server (NAS)
Management";
}
feature local-users { If present, the NETCONF server will only allow
if-feature authentication; the designated 'superuser' to have write or execute
description default nacm-rights-type for the node. An explicit access
"Indicates that the NETCONF server supports control rule is required for all other users.
local user authentication.";
}
/* The 'secure' extension may appear within a data, rpc,
* Identities or notification node definition. It is ignored
*/ otherwise.";
}
identity authentication-method { extension very-secure {
description description
"Base identity for NETCONF authentication methods."; "Used to indicate that the data model node
} controls a very sensitive security system parameter.
identity radius { If present, the NETCONF server will only allow
base authentication-method; the designated 'superuser' to have read, write, or execute
description default nacm-rights-type for the node. An explicit access
"Indicates NETCONF authentication using RADIUS."; control rule is required for all other users.
reference
"RFC 2865: Remote Authentication Dial In User Service (RADIUS)
RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
Authorization for Network Access Server (NAS)
Management";
}
identity local-users { The 'very-secure' extension may appear within a data, rpc,
base authentication-method; or notification node definition. It is ignored
description otherwise.";
"Indicates password-based NETCONF authentication using locally }
configured users.";
}
/* /*
* Derived types * Derived types
*/ */
typedef nacm-user-name-type { typedef nacm-user-name-type {
type string { type string {
length "1..max"; length "1..max";
}
description
"General Purpose User Name string.";
} }
description
"General Purpose User Name string.";
}
typedef nacm-matchall-string-type { typedef nacm-matchall-string-type {
type string { type string {
pattern "\*"; pattern "\*";
}
description
"The string containing a single asterisk '*' is used
to conceptually represent all possible values
for the particular leaf using this data type.";
} }
description
"The string containing a single asterisk '*' is used
to conceptually represent all possible values
for the particular leaf using this data type.";
}
typedef nacm-rights-type { typedef nacm-rights-type {
type union { type union {
type nacm-matchall-string-type; type nacm-matchall-string-type;
type bits { type bits {
bit create { bit create {
description description
"Create access allowed to all specified data. "Create access allowed to all specified data.
Any protocol operation that creates a Any protocol operation that creates a
new instance of the specified data is a create new instance of the specified data is a create
operation."; operation.";
} }
bit read { bit read {
description description
"Read access allowed to all specified data. "Read access allowed to all specified data.
Any protocol operation or notification that Any protocol operation or notification that
returns data to an application is a read returns data to an application is a read
operation."; operation.";
} }
bit update { bit update {
description description
"Update access allowed to all specified data. "Update access allowed to all specified data.
Any protocol operation that alters an existing Any protocol operation that alters an existing
data node is an update operation."; data node is an update operation.";
} }
bit delete { bit delete {
description description
"Delete access allowed to all specified data. "Delete access allowed to all specified data.
Any protocol operation that removes a database Any protocol operation that removes a database
node instance is a delete operation."; node instance is a delete operation.";
} }
bit exec { bit exec {
description description
"Execution access to the specified RPC operation. "Execution access to the specified RPC operation.
Any RPC operation invocation is an exec operation."; Any RPC operation invocation is an exec operation.";
}
} }
} }
description
"NETCONF Access Rights.
The string '*' indicates that all possible access
rights apply to the access rule. Otherwise, only
the specific access rights represented by the bit names
that are present apply to the access rule.";
} }
description
"NETCONF Access Rights.
The string '*' indicates that all possible access
rights apply to the access rule. Otherwise, only
the specific access rights represented by the bit names
that are present apply to the access rule.";
}
typedef nacm-group-name-type { typedef nacm-group-name-type {
type string { type string {
length "1..max"; length "1..max";
pattern "[^\*].*"; pattern "[^\*].*";
}
description
"Name of administrative group that can be
assigned to the user, and specified in
an access control rule.";
} }
description
"Name of administrative group that can be
assigned to the user, and specified in
an access control rule.";
}
typedef nacm-action-type { typedef nacm-action-type {
type enumeration { type enumeration {
enum permit { enum permit {
description description
"Requested action is permitted."; "Requested action is permitted.";
} }
enum deny { enum deny {
description description
"Requested action is denied."; "Requested action is denied.";
}
} }
description
"Action taken by the server when a particular
rule matches.";
} }
description
"Action taken by the server when a particular
rule matches.";
} typedef schema-instance-identifier {
type yang:xpath1.0;
typedef schema-instance-identifier { description
type yang:xpath1.0; "Path expression used to represent a special
description schema-instance identifier string.
"Path expression used to represent a special
schema-instance identifier string.
A schema-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 schema-instance-identifier
represents all possible server instances for that key.
This XPath expression is evaluated in the following context: A schema-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 schema-instance-identifier
represents all possible server instances for that key.
o The set of namespace declarations are those in scope on This XPath expression is evaluated in the following context:
the leaf element where this type is used.
o The set of variable bindings contains one variable, o The set of namespace declarations are those in scope on
'USER', which contains the name of user of the current the leaf element where this type is used.
session.
o The function library is the core function library, but o The set of variable bindings contains one variable,
note that due to the syntax restrictions of an 'USER', which contains the name of user of the current
instance-identifier, no functions are allowed. session.
o The context node is the root node in the data tree."; 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.
typedef md5-crypt { o The context node is the root node in the data tree.";
type string {
pattern "$0$.* | $1$[a-zA-Z0-9./]{2,8}$.*";
} }
description
"The md5-crypt type is used to store a password hash based on the
MD5 message digest algorithm. When a clear text value is set to
a leaf of this type, the server calculates a MD5 password hash,
and stores the result in the datastore. Thus, the password is
never stored in clear text.
When a leaf of this type is read, the stored password hash is container nacm {
returned.
A value of this type matches one of the forms:
$0$<clear text password>
$1$<salt>$<password hash>
The '$0$' prefix signals that the value is clear text. When
such a value is received by the server, an MD5 digest is
calculated, and the string '$1$<salt>$' is prepended to the
result, where <salt> is a random 2-8 characters long salt used
to generate the digest. This value is stored in the
configuration data store.
If a value starting with '$1$<salt>$' is received, the server
knows that the value already represents an MD5 digest, and
stores it as is in the data store.
When a server needs to verify a password given by a user, it
finds the stored password hash string for that user, extracts
the salt, and calculates the hash with the salt and given
password as input. If the calculated hash value is the same as
the stored value, the password given by the client is correct.
The digest algorithm is the md5 crypt function used for
encrypting passwords for various UNIX systems.";
reference
"RFC 1321: The MD5 Message-Digest Algorithm
http://en.wikipedia.org/wiki/Crypt_(Unix)";
// FIXME: ref to wikipedia ok??
}
container nacm {
nacm:very-secure;
presence
"An empty nacm container indicates that the
NACM service is running, and using
all default parameters.";
description
"Parameters for NETCONF Access Control Model.";
container authentication {
nacm:very-secure; nacm:very-secure;
if-feature authentication;
description description
"The authentication configuration for the "Parameters for NETCONF Access Control Model.";
NETCONF server.";
leaf-list user-authentication-order { leaf enable-nacm {
type identityref { type boolean;
base authentication-method; default true;
} description
must '(. = "nacm:radius" and ../radius/server) or' "Enable or disable all NETCONF access control
+ '(. != "nacm:radius")' { enforcement. If 'true', then enforcement
error-message is enabled. If 'false', then enforcement
"When 'radius' is used, a radius server is disabled.";
must be configured."; }
}
ordered-by user;
leaf read-default {
type nacm-action-type;
default "permit";
description description
"When the NETCONF server authenticates a user with "Controls whether read access is granted if
a password, it tries the authentication methods in this no appropriate rule is found for a
leaf-list in order. If authentication with one method particular read request.";
fails, the next method is used. If no method succeeds, }
the user is denied access.
If the 'radius' feature is advertised by the NETCONF leaf write-default {
server, the 'radius' identity can be added to this type nacm-action-type;
list. default "deny";
description
"Controls whether create, update, or delete access
is granted if no appropriate rule is found for a
particular write request.";
}
If the 'local-users' feature is advertised by the leaf exec-default {
NETCONF server, the 'local-users' identity can be type nacm-action-type;
added to this list."; default "permit";
description
"Controls whether exec access is granted if no appropriate
rule is found for a particular RPC operation request.";
} }
container radius { leaf denied-rpcs {
if-feature radius; type yang:zero-based-counter32;
config false;
mandatory true;
description
"Number of times an RPC operation request was denied
since the server last restarted.";
}
leaf denied-data-writes {
type yang:zero-based-counter32;
config false;
mandatory true;
description description
"The radius configuration for the NETCONF server."; "Number of times a request to alter a data node
was denied, since the server last restarted.";
}
list server { container groups {
key address; description
"NETCONF Access Control Groups.";
list group {
key name;
description description
"The radius server configuration used by "One NACM Group Entry.";
the NETCONF server.";
leaf address { leaf name {
type inet:host; type nacm-group-name-type;
description
"The address of the radius server.";
}
leaf port {
type inet:port-number;
default "1812";
description description
"The port number of the radius server."; "Group name associated with this entry.";
} }
leaf shared-secret {
type string; // FIXME
/*
We're using a special type aes-cfb-128-encrypted-string which works
like the md5-crypt string, but encrypts the clear text value using a
pre-provisioned password (not part of the config db!).
We use $0$ for cleartext and $4$ for the encrypted value.
(we also have a des-version which uses $3$).
But I was thinking that maybe we could define a type for encrypted
values without specifying the encryption algorithm, just specifying
the format. $0$<clear text> | $x$<encrypted value>, and how it is
encrypted is implementation specific.
One alternative is to store this shared secret in clear text. It is leaf-list user-name {
transmitted over a secure transport, and marked as very-secure. (The type nacm-user-name-type;
same argument could be made for user passwords, but these are
personal and not even root should be able to read my passwd in clear
text, so it makes more sense to keep them hidden.)
*/
description description
"The shared secret which is known to both the RADIUS "Each entry identifies the user name of
client and server."; a member of the group associated with
reference this entry.";
"RFC 2865: Remote Authentication Dial In User Service";
} }
/*
How about configuration of number of retransmits
and timeout?
*/
} }
} }
container rules {
list user {
if-feature local-users;
key name;
description description
"The list of local users configured on this device."; "NETCONF Access Control Rules.";
leaf name {
type nacm-user-name-type;
description
"The user name string identifying this entry.";
} grouping common-rule-parms {
leaf password {
type md5-crypt;
description
"The password for this entry.";
}
leaf ssh-dsa {
type binary;
description
"The public DSA key for this entry.";
}
leaf ssh-rsa {
type binary;
description description
"The public RSA key for this entry."; "Common rule parameters.";
}
}
}
leaf enable-nacm {
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 nacm-action-type;
default "permit";
description
"Controls whether read access is granted if
no appropriate rule is found for a
particular read request.";
}
leaf write-default {
type nacm-action-type;
default "deny";
description
"Controls whether create, update, or delete access
is granted if no appropriate rule is found for a
particular write request.";
}
leaf exec-default { leaf rule-name {
type nacm-action-type; type string {
default "permit"; length "1..256";
description }
"Controls whether exec access is granted if no appropriate description
rule is found for a particular RPC operation request."; "Arbitrary name assigned to the
} access control rule.";
}
leaf denied-rpcs { leaf allowed-rights {
type yang:zero-based-counter32; type nacm-rights-type;
config false; description
mandatory true; "List of access rights granted to
description specified administrative groups for the
"Number of times an RPC operation request was denied content specified by the associated path.";
since the server last restarted."; }
}
leaf denied-data-writes { leaf-list allowed-group {
type yang:zero-based-counter32; type union {
config false; type nacm-matchall-string-type;
mandatory true; type nacm-group-name-type;
description }
"Number of times a request to alter a data node min-elements 1;
was denied, since the server last restarted."; description
} "List of administrative groups which will be
assigned the associated access rights
for the content specified by the associated path.
container groups { The string '*' indicates that all configured
list group { administrative groups apply to the entry.";
key name; }
description leaf nacm-action {
"One NACM Group Entry."; type nacm-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 name { leaf comment {
type nacm-group-name-type; type string {
description length "1..4095";
"Group name associated with this entry."; }
description
"A textual description of the access rule.";
}
} }
leaf-list user-name { list module-rule {
type nacm-user-name-type; key "module-name rule-name";
description ordered-by user;
"Each entry identifies the user name of
a member of the group associated with
this entry.";
}
}
}
container rules {
description
"NETCONF Access Control Rules.";
grouping common-rule-parms {
leaf rule-name {
type string {
length "1..256";
}
description description
"Arbitrary name assigned to the "One Module Access Rule.
access control rule.";
}
leaf allowed-rights { Rules are processed in user-defined order. A module rule
type nacm-rights-type; is considered a match if the XML namespace for the
description specified module name matches the XML namespace used
"List of access rights granted to within a NETCONF PDU, and the administrative group
specified administrative groups for the associated with the requesting session is specified in the
content specified by the associated path."; 'allowed-group' leaf-list, and the requested operation
} is included in the 'allowed-rights' leaf.";
leaf-list allowed-group { leaf module-name {
type union { type string;
type nacm-matchall-string-type; description
type nacm-group-name-type; "Name of the module associated with this rule.";
} }
min-elements 1;
description
"List of administrative groups which will be
assigned the associated access rights
for the content specified by the associated path.
The string '*' indicates that all configured
administrative groups apply to the entry.";
}
leaf nacm-action { uses common-rule-parms {
type nacm-action-type; refine allowed-rights {
mandatory true; 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 comment {
type string {
length "1..4095";
} }
description
"A textual description of the access rule.";
} }
}
list module-rule { list rpc-rule {
key "module-name rule-name"; key "module-name rpc-name rule-name";
ordered-by user; ordered-by user;
description
"One Module Access Rule.
Rules are processed in user-defined order. A module rule
is considered a match if the XML namespace for the
specified module name matches the XML namespace used
within a NETCONF PDU, and the administrative group
associated with the requesting session is specified in the
'allowed-group' leaf-list, and the requested operation
is included in the 'allowed-rights' leaf.";
leaf module-name {
type string;
description description
"Name of the module associated with this rule."; "One RPC Operation Access Rule.
}
uses common-rule-parms {
refine allowed-rights {
mandatory true;
}
}
}
list rpc-rule {
key "module-name rpc-name rule-name";
ordered-by user;
description Rules are processed in user-defined order. An RPC rule is
"One RPC Operation Access Rule. considered a match if the module name of the requested RPC
operation matches 'module-name', the requested RPC
operation matches 'rpc-name', and an administrative group
associated with the session user is listed in the
'allowed-group' leaf-list. The 'allowed-rights' leaf
is ignored by the server if it is present.
Only the 'exec' bit can possibly cause
a match for an RPC rule.";
Rules are processed in user-defined order. An RPC rule is leaf module-name {
considered a match if the module name of the requested RPC type string;
operation matches 'module-name', the requested RPC description
operation matches 'rpc-name', and an administrative group "Name of the module defining this RPC operation.";
associated with the session user is listed in the }
'allowed-group' leaf-list. The 'allowed-rights' leaf
is ignored by the server if it is present.
Only the 'exec' bit can possibly cause
a match for an RPC rule.";
leaf module-name { leaf rpc-name {
type string; type string;
description description
"Name of the module defining this RPC operation."; "Name of the RPC operation.";
} }
leaf rpc-name { uses common-rule-parms;
type string;
description
"Name of the RPC operation.";
} }
uses common-rule-parms; list data-rule {
} key "rule-name";
ordered-by user;
list data-rule {
key "rule-name";
ordered-by user;
description description
"One Data Access Control Rule. "One Data Access Control Rule.
Rules are processed in user-defined order. A data rule is Rules are processed in user-defined order. A data rule is
considered to match when the path expression identifies considered to match when the path expression identifies
the same node that is being accessed in the NETCONF the same node that is being accessed in the NETCONF
database, and the administrative group associated with the database, and the administrative group associated with the
session is identified in the 'allowed-group' leaf-list, session is identified in the 'allowed-group' leaf-list,
and the requested operation is included in the and the requested operation is included in the
'allowed-rights' leaf."; 'allowed-rights' leaf.";
leaf path { leaf path {
type schema-instance-identifier; type schema-instance-identifier;
mandatory true; mandatory true;
description description
"Schema Instance Identifier associated with the data node "Schema Instance Identifier associated with the data node
controlled by this rule. controlled by this rule.
Configuration data or state data instance identifiers Configuration data or state data instance identifiers
start with a top-level data node. A complete instance start with a top-level data node. A complete instance
identifier is required for this type of path value. identifier is required for this type of path value.
The special value '/' refers to all possible database The special value '/' refers to all possible database
contents."; contents.";
} }
uses common-rule-parms { uses common-rule-parms {
refine allowed-rights { refine allowed-rights {
mandatory true; mandatory true;
}
} }
} }
}
list notification-rule { list notification-rule {
key "module-name key "module-name
notification-name notification-name
rule-name"; rule-name";
ordered-by user; ordered-by user;
description description
"One Notification Access Rule. "One Notification Access Rule.
A notification is considered a match if the module name of A notification is considered a match if the module name of
the requested event type matches the requested event type matches
'module-name', the requested event type 'module-name', the requested event type
matches the 'notification-name', and the administrative matches the 'notification-name', and the administrative
group associated with the requesting session is listed in group associated with the requesting session is listed in
the 'allowed-group' leaf-list. If the 'allowed-rights' the 'allowed-group' leaf-list. If the 'allowed-rights'
leaf is present, it is ignored by the server. leaf is present, it is ignored by the server.
Only the 'read' bit can possibly cause Only the 'read' bit can possibly cause
a match for a notification rule."; a match for a notification rule.";
leaf module-name { leaf module-name {
type string; type string;
description description
"Name of the module defining this "Name of the module defining this
notification event type."; notification event type.";
} }
leaf notification-name { leaf notification-name {
type string; type string;
description description
"Name of the notification event."; "Name of the notification event.";
} }
uses common-rule-parms; uses common-rule-parms;
}
} }
} }
} }
}
<CODE ENDS> <CODE ENDS>
Figure 5 Figure 5
5.5. IANA Considerations 3.5. 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-nacm 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-nacm name: ietf-netconf-acm
namespace: urn:ietf:params:xml:ns:yang:ietf-nacm 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
5.6. Security Considerations 3.6. 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.
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.
skipping to change at page 51, line 10 skipping to change at page 42, line 13
If the server chooses to allow user configuration of the access If the server chooses to allow user configuration of the access
control system, then only sessions using the 'superuser' control system, then only sessions using the 'superuser'
administrative user should be allowed to have write access to the administrative user should be allowed to have write access to the
data model. data model.
If the server chooses to allow user retrieval of the access control If the server chooses to allow user retrieval of the access control
system configuration, then only sessions using the 'superuser' system configuration, then only sessions using the 'superuser'
administrative user should be allowed to have read access to the data administrative user should be allowed to have read access to the data
model. model.
There is a risk that invocation of non-standard RPC operations will There is a risk that invocation of non-standard protocol operations
have undocumented side effects. An administrator should construct will have undocumented side effects. An administrator should
access control rules such that the configuration database is construct access control rules such that the configuration datastore
protected from such side effects. Also, such RPC operations should is protected from such side effects. Also, such protocol operations
never be invoked by a session using the 'superuser' administrative should never be invoked by a session using the 'superuser'
user. administrative user.
There is a risk that non-standard RPC operations, or even the There is a risk that non-standard protocol operations, or even the
standard <get> operation, may return data which 'aliases' or 'copies' standard <get> operation, may return data which 'aliases' or 'copies'
sensitive data from a different data object. In this case, the sensitive data from a different data object. In this case, the
namespace and/or the element name will not match the values for the namespace and/or the element name will not match the values for the
sensitive data, which is then fully or partially copied into a sensitive data, which is then fully or partially copied into a
different namespace and/or element. An administrator should avoid different namespace and/or element. An administrator should avoid
using data models which use this practice. using data models which use this practice.
An administrator should restrict write access to all configurable An administrator should restrict write access to all configurable
objects within this data model. It is suggested that only sessions objects within this data model. It is suggested that only sessions
using the 'superuser' administrative role be permitted to configure using the 'superuser' administrative role be permitted to configure
skipping to change at page 51, line 47 skipping to change at page 43, line 4
o enable-nacm o enable-nacm
o read-default o read-default
o write-default o write-default
o exec-default o exec-default
o groups o groups
o rules o rules
6. Normative References 4. 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.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
[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.
[RFC4252] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, January 2006.
[RFC4253] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
Transport Layer Protocol", RFC 4253, January 2006.
[RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741,
December 2006.
[RFC4742] Wasserman, M. and T. Goddard, "Using the NETCONF
Configuration Protocol over Secure SHell (SSH)", RFC 4742,
December 2006.
[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.
[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In
User Service (RADIUS) Authorization for Network Access
Server (NAS) Management", RFC 5607, July 2009.
[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.
[W3C.REC-xml] [I-D.ietf-netconf-4741bis]
Bray, T., Paoli, J., Sperberg-McQueen, C., and E. Maler, Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
"Extensible Markup Language (XML) 1.0 (2nd ed)", W3C REC- Bierman, "Network Configuration Protocol (NETCONF)",
xml, October 2000, <http://www.w3.org/TR/REC-xml>. draft-ietf-netconf-4741bis-07 (work in progress),
January 2011.
[I-D.ietf-netconf-rfc4742bis]
Wasserman, M. and T. Goddard, "Using the NETCONF
Configuration Protocol over Secure Shell (SSH)",
draft-ietf-netconf-rfc4742bis-06 (work in progress),
January 2011.
4.2. Informative References
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In
User Service (RADIUS) Authorization for Network Access
Server (NAS) Management", RFC 5607, July 2009.
Appendix A. Usage Examples Appendix A. Usage Examples
The following XML snippets are provided as examples only, to The following XML snippets are provided as examples only, to
demonstrate how NACM can be configured to perform some access control demonstrate how NACM can be configured to perform some access control
tasks. tasks.
A.1. <groups> Example A.1. <groups> Example
There must be at least one <group> entry in order for any of the There must be at least one <group> entry in order for any of the
access control rules to be useful. access control rules to be useful.
The following XML shows arbitrary groups, and is not intended to The following XML shows arbitrary groups, and is not intended to
represent any particular use-case. represent any particular use-case.
<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-nacm"> <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>monitor</name>
<user-name>wilma</user-name> <user-name>wilma</user-name>
skipping to change at page 54, line 15 skipping to change at page 46, line 15
3. The nacm:guest group contains 2 users named 'guest' and 3. The nacm: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. These rules are checked after none of the a specific module. These rules are checked after none of the
specific rules (i.e., rpc-rule, data-rule, or notification-rule) specific rules (i.e., rpc-rule, data-rule, or notification-rule)
matched the current access request. matched the current access request.
<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-nacm"> <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
<rules> <rules>
<module-rule> <module-rule>
<module-name>ietf-netconf-monitoring</module-name> <module-name>ietf-netconf-monitoring</module-name>
<rule-name>mod-1</rule-name> <rule-name>mod-1</rule-name>
<allowed-rights>*</allowed-rights> <allowed-rights>*</allowed-rights>
<allowed-group>guest</allowed-group> <allowed-group>guest</allowed-group>
<nacm-action>deny</nacm-action> <nacm-action>deny</nacm-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.
skipping to change at page 55, line 27 skipping to change at page 47, line 27
</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 mod-1: 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- mod-2: This rule allows the monitor group to read the ietf-netconf-
monitoring YANG module. monitoring YANG module.
mod-3: This rule allows the monitor group to invoke any RPC mod-3: This rule allows the monitor group to invoke any protocol
operation supported by the server. operation supported by the server.
mod-4: This rule allows the admin group complete access to all mod-4: This rule allows the admin group complete access to all
content in the server. No subsequent rule will match for the 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 RPC operation. RPC rules are used to control access to a specific protocol
operation.
<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-nacm"> <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
<rules> <rules>
<rpc-rule> <rpc-rule>
<module-name>ietf-netconf</module-name> <module-name>ietf-netconf</module-name>
<rpc-name>kill-session</rpc-name> <rpc-name>kill-session</rpc-name>
<rule-name>rpc-1</rule-name> <rule-name>rpc-1</rule-name>
<allowed-group>monitor</allowed-group> <allowed-group>monitor</allowed-group>
<allowed-group>guest</allowed-group> <allowed-group>guest</allowed-group>
<nacm-action>deny</nacm-action> <nacm-action>deny</nacm-action>
<comment> <comment>
Do not allow the monitor or guest group Do not allow the monitor or guest group
skipping to change at page 56, line 46 skipping to change at page 48, line 46
<rule-name>rpc-3</rule-name> <rule-name>rpc-3</rule-name>
<allowed-group>monitor</allowed-group> <allowed-group>monitor</allowed-group>
<nacm-action>permit</nacm-action> <nacm-action>permit</nacm-action>
<comment> <comment>
Allow the monitor group to edit the configuration. Allow the monitor group to edit the configuration.
</comment> </comment>
</rpc-rule> </rpc-rule>
</rules> </rules>
</nacm> </nacm>
This example shows 3 RPC operation rules: This example shows 3 protocol operation rules:
rpc-1: This rule prevents the monitor or guest groups from invoking rpc-1: This rule prevents the monitor or guest groups from invoking
the NETCONF <kill-session> RPC operation. the NETCONF <kill-session> protocol operation.
rpc-2: This rule prevents the monitor or guest groups from invoking rpc-2: This rule prevents the monitor or guest groups from invoking
the NETCONF <delete-config> RPC operation. the NETCONF <delete-config> protocol operation.
rpc-3: This rule allows the monitor group to invoke the NETCONF rpc-3: This rule allows the monitor group to invoke the NETCONF
<edit-config> RPC operation. This rule will have no real affect <edit-config> protocol operation. This rule will have no real
unless the 'exec-default' leaf is set to 'deny'. affect 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-nacm"> <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
<rules> <rules>
<data-rule> <data-rule>
<rule-name>data-1</rule-name> <rule-name>data-1</rule-name>
<path>/nacm</path> <path>/nacm</path>
<allowed-rights>*</allowed-rights> <allowed-rights>*</allowed-rights>
<allowed-group>guest</allowed-group> <allowed-group>guest</allowed-group>
<nacm-action>deny</nacm-action> <nacm-action>deny</nacm-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>
skipping to change at page 59, line 15 skipping to change at page 51, line 15
admin-itf: This rule gives the admin group read-write access to all admin-itf: This rule gives the admin group read-write access to all
acme <interface>. entries. This is an example of an unreachable acme <interface>. entries. This is an example of an unreachable
rule because the 'mod-3' rule already gives the admin group full rule because the 'mod-3' rule already gives the admin group full
access to this data. 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-nacm"> <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
<rules> <rules>
<notification-rule> <notification-rule>
<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>
<rule-name>notif-1</rule-name> <rule-name>notif-1</rule-name>
<allowed-group>monitor</allowed-group> <allowed-group>monitor</allowed-group>
<allowed-group>guest</allowed-group> <allowed-group>guest</allowed-group>
<nacm-action>deny</nacm-action> <nacm-action>deny</nacm-action>
<comment> <comment>
Do not allow the guest or monitor groups Do not allow the guest or monitor groups
skipping to change at page 60, line 5 skipping to change at page 52, line 5
</comment> </comment>
</notification-rule> </notification-rule>
</rules> </rules>
</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 notif-1: This rule prevents the monitor or guest groups from
receiving the acme <sys-config-change> event type. receiving the acme <sys-config-change> event type.
Appendix B. Open Issues Appendix B. Change Log
-- RFC Ed.: remove this section before publication. -- RFC Ed.: remove this section before publication.
1. Do modules need to be identified by their XML namespace URI, or B.1. 01-02
is the module name good enough?
2. Are any more wildcard mechanisms needed to specify the scope of
an access control rule?
3. Should regular expressions (module='foo-*') be allowed in schema-
instance-identifier strings?
4. Should XPath be allowed for specifying access control rules for
data nodes?
5. Are any 'access-denied' notifications needed?
6. Should data rules support nodes that would not be eligible for
retrieval with the <get> operation? If so, should schema nodes
such as rpc 'input' or 'output' be in the path expression? How
would notification content be identified?
7. Do any external access control models need to be supported Removed authentication text and objects.
somehow? For example, should the <groups> configuration be
optionally read-only, so it can just mirror the internal
(external or proprietary) group configuration?
8. Should the nacm:secure and nacm:very-secure extensions be Changed module name from ietf-nacm to ietf-netconf-acm.
optional to support, via a YANG feature?
9. Should the default access levels (e.g., read-default) be more Updated NETCONF and YANG terminology.
restrictive by default? Shiuld these defaults be a vendor
decision? An operator decision? It is important that the server
be able to install a factory default <nacm> container if needed.
Appendix C. Change Log Removed open issues section.
-- RFC Ed.: remove this section before publication. Changed some must to MUST in requirements section.
C.1. 00-01 B.2. 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.
C.2. 00 B.3. 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. 
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