draft-ietf-netconf-access-control-02.txt   draft-ietf-netconf-access-control-03.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: August 7, 2011 Tail-f Systems Expires: September 12, 2011 Tail-f Systems
February 3, 2011 March 11, 2011
Network Configuration Protocol Access Control Model Network Configuration Protocol Access Control Model
draft-ietf-netconf-access-control-02 draft-ietf-netconf-access-control-03
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
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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 August 7, 2011. This Internet-Draft will expire on September 12, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.1. Normative References . . . . . . . . . . . . . . . . . . . 44 4.1. Normative References . . . . . . . . . . . . . . . . . . . 44
4.2. Informative References . . . . . . . . . . . . . . . . . . 44 4.2. Informative References . . . . . . . . . . . . . . . . . . 44
Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 45 Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 45
A.1. <groups> Example . . . . . . . . . . . . . . . . . . . . . 45 A.1. <groups> Example . . . . . . . . . . . . . . . . . . . . . 45
A.2. <module-rule> Example . . . . . . . . . . . . . . . . . . 46 A.2. <module-rule> Example . . . . . . . . . . . . . . . . . . 46
A.3. <rpc-rule> Example . . . . . . . . . . . . . . . . . . . . 47 A.3. <rpc-rule> Example . . . . . . . . . . . . . . . . . . . . 47
A.4. <data-rule> Example . . . . . . . . . . . . . . . . . . . 49 A.4. <data-rule> Example . . . . . . . . . . . . . . . . . . . 49
A.5. <notification-rule> Example . . . . . . . . . . . . . . . 51 A.5. <notification-rule> Example . . . . . . . . . . . . . . . 51
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 52 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 52
B.1. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 52 B.1. 02-03 . . . . . . . . . . . . . . . . . . . . . . . . . . 52
B.2. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 52 B.2. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 52
B.3. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 B.3. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 52
B.4. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 53 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 53
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
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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.
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 will 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. Access Control Requirements 2. Access Control Requirements
2.1. 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 need to be protected at several
conceptual control points. conceptual control points.
+-------------+ +-------------+ +-------------+ +-------------+
client | protocol | | prune | client client | protocol | | prune | client
request --> | operation | | restricted | ---> reply request --> | operation | | restricted | ---> reply
| allowed? | | <rpc-reply> | | allowed? | | <rpc-reply> |
+-------------+ | nodes? | +-------------+ | nodes? |
| +-------------+ | +-------------+
| if any datastore or | if any datastore or
| state data is accessed | state data is accessed
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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.
2.2. Simplicity 2.2. Simplicity
Experience has shown that a complicated ACM will not be widely Experience has shown that a complicated ACM will not be widely
deployed, because it is too hard to use. The key factor that is deployed, because it is too hard to use. The key factor that is
ignored in such solutions is the concept of 'localized cost'. It ignored in such solutions is the concept of 'localized cost'. It
should be easy to do simple things, and hard to do complex things, needs to 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 needs to be simple to use.
Simple and common tasks should be easy to configure, and require Simple and common tasks need to be easy to configure, and require
little expertise or domain-specific knowledge. Complex tasks should little expertise or domain-specific knowledge. Complex tasks are
be possible using additional mechanisms which may require additional 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 protocol operation invocation, all conceptual types of NETCONF protocol operation invocation, all conceptual
datastore 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 datastore 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.
2.3. 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 protocol operations is not required. input parameters to protocol operations is not required.
2.4. Datastore Access 2.4. Datastore Access
It must be possible to 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 datastore. within the conceptual NETCONF datastore.
In order for a user to obtain access to a particular datastore 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 datastores. The same access control rules apply to all conceptual datastores.
For example, the candidate configuration or the running For example, the candidate configuration or the running
configuration. configuration.
Only the standard NETCONF datastores (candidate, running, and Only the standard NETCONF datastores (candidate, running, and
startup) are controlled by the ACM. Local or remote files or startup) are controlled by the ACM. Local or remote files or
datastores accessed via the <url> parameter are optional to support. datastores accessed via the <url> parameter are optional to support.
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the corresponding datastore 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 datastore. 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 datastore 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.
2.4.4. <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
datastore. Read access to the entire source datastore, and write datastore. Read access to the entire source datastore, and write
access to the entire target datastore is needed for this operation to access to the entire target datastore is needed for this operation to
succeed. succeed.
A client must have access to every datastore 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 (client) MUST have full read access
datastore in order to receive a complete copy of its contents. If to the datastore in order to receive a complete copy of its contents.
not, the server will simply omit these sub-trees from the reply. If If not, the server will simply omit these sub-trees from the reply.
that copy is later used to restore the server datastore, the server If that copy is later used to restore the server datastore, the
will interpret the missing nodes as a request to delete those nodes, server will interpret the missing nodes as a request to delete those
and return an error. nodes, and return an error.
2.5. Users and Groups 2.5. Users and Groups
The server must obtain a user name from the underlying NETCONF 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 may be needed which bypasses all
control rules. This is needed in case the access control rules are access control rules. This could be needed in case the access
mis-configured, and all access is denied. control rules are mis-configured, and all access is denied by
mistake.
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.
It must be possible to delegate the user-to-group mapping to a It MUST be possible to delegate the user-to-group mapping to a
central server, such as RADIUS [RFC2865] [RFC5607]. Since central server, such as RADIUS [RFC2865] [RFC5607]. Since
authentication is performed by the NETCONF transport layer, and authentication is performed by the NETCONF transport layer, and
RADIUS performs authentication and service authorization at the same RADIUS performs authentication and service authorization at the same
time, it must be possible for the underlying NETCONF transport to time, it MUST be possible for the underlying NETCONF transport to
report a set of group names associated with the user to the server. report a set of group names associated with the user to the server.
2.6. Maintenance 2.6. Maintenance
It should be possible to disable part or all of the access control It 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.
2.7. 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 datastore 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 can be used to identify the sub-tree(s) for this purpose.
purpose.
2.8. 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 mandatory for security-sensitive objects to be documented in It is mandatory for security-sensitive objects to be documented in
the Security Considerations section of an RFC. This is nice, but it the Security Considerations section of an RFC. This is nice, but it
is not good enough, for the following reasons: is not good enough, for the following reasons:
o This documentation-only approach forces operators to study the RFC o This documentation-only approach forces 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 can 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).
o The ACM on each server must be configured to close the security o The ACM on each server can be configured to close the security
holes, e.g., require privileged access to read or write the holes, e.g., require privileged access to read or write the
specific data identified in the Security Considerations section. specific data identified in the Security Considerations section.
o If the ACM is not pre-configured, then there will be a time window o If the ACM is not pre-configured, then there will be a time window
of vulnerability, after the new module is loaded, and before the of vulnerability, after the new 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 needs to be able to use machine-readable
statements to identify NETCONF content which should be protected by statements to identify NETCONF content which needs to be protected by
default. This will allow client and server tools to automatically default. This will allow client and server tools to automatically
close data-model specific security holes, by denying access to 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.
2.9. 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
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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 ensure that unauthorized access to its A NETCONF server MUST ensure that unauthorized access to its
conceptual datastores 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 can
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.
2.10. 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 datastore access request, The server MUST be able to identify any datastore access request,
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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. If the server supports a 'superuser' account, then it
account is available, and if so, the actual user name for this MUST be able to determine the actual user name for this account.
account. A session associated with the superuser account will A session associated with the superuser account will bypass all
bypass all access control enforcement. access control enforcement.
o A simple and familiar set of datastore permissions is used. o A simple and familiar set of datastore permissions is used.
o Support for YANG security tagging (e.g., nacm:secure extension) o Support for YANG security tagging (e.g., nacm: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.
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o Access control is applied to all <rpc> messages (except <close- o Access control is applied to all <rpc> messages (except <close-
session>) received by the server, individually, for each active session>) received by the server, individually, for each active
session, unless the session is associated with the 'superuser' session, unless the session is associated with the 'superuser'
account. 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 datastore or conceptual state data is o If the configuration datastore or conceptual state data is
accessed by the protocol operation, then the data node access must accessed by the protocol operation, then the data node access MUST
be authorized. If the session is authorized to perform the be authorized. If the 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.
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3.2. 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.
3.2.1. Users 3.2.1. Users
A 'user' is the conceptual entity, 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.
As described in [I-D.ietf-netconf-4741bis], the user name string is As described in [I-D.ietf-netconf-4741bis], the user name string is
derived from the transport layer during session establishment. If derived from the transport layer during session establishment. If
the transport layer cannot authenticate the user, the session is the transport layer cannot authenticate the user, the session is
terminated. terminated.
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.
3.2.2. 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.
3.2.3. Sessions 3.2.3. 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.
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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.
3.3. 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 need to be addressed, four of
are related to the NETCONF message processing model. In addition, which are related to the NETCONF message processing model. In
the initial start-up mode for a NETCONF server, session addition, the initial start-up mode for a NETCONF server, session
establishment, and 'access-denied' error handling procedures must establishment, and 'access-denied' error handling procedures also
also be considered. need to be considered.
3.3.1. 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
MUST 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.
3.3.2. 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, the NETCONF transport layer reports the username and a authenticated, the NETCONF transport layer reports the username and a
possibly empty set of group names associated with the user to the possibly empty set of group names associated with the user to the
NETCONF server. The NETCONF server will enforce the access control NETCONF server. The NETCONF server will enforce the access control
rules, based on the supplied user identity, group names, and the rules, based on the supplied user identity, group names, and the
configuration data stored on the server. configuration data stored on the server.
3.3.3. '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 a protocol system denies access to either a request to invoke a protocol
operation or a request to perform a particular operation on the operation or a request to perform a particular operation on the
configuration datastore. configuration datastore.
A server must not include any sensitive information in any <error- A server MUST NOT include any sensitive information in any <error-
info> elements within the <rpc-error> response. info> elements within the <rpc-error> response.
3.3.4. Incoming RPC Message Validation 3.3.4. 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
+------------+ +------------+
skipping to change at page 21, line 38 skipping to change at page 21, line 38
V V V V
+----------------------+ +----------------------+
| | | |
| configuration | | configuration |
| datastore | | 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 will 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 protocol operation being namespace URI and the element name of the protocol operation being
requested, the RPC access control enforcer verifies that the session requested, the RPC access control enforcer verifies that the session
is authorized to invoke the protocol operation. is authorized to invoke the protocol operation.
The protocol operation is authorized by following these steps: The protocol operation is authorized by following these steps:
1. If the <enable-nacm> parameter is set to 'false', then the 1. If the <enable-nacm> parameter is set to 'false', then the
protocol operation is permitted. protocol operation is permitted.
skipping to change at page 26, line 7 skipping to change at page 26, line 7
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 include 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.
3.3.6. 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 MUST be checked by the server to make sure no
no unauthorized data is contained within it. If so, the restricted unauthorized data is contained within it. If so, the restricted data
data must be removed from the message before it is sent to the MUST be removed from the message before it is sent to the client.
client.
For protocol 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 protocol operation is also authorized client authorized to invoke the protocol operation is also authorized
to receive the <rpc-reply> for that protocol operation. to receive the <rpc-reply> for that protocol operation.
3.3.7. Outgoing <notification> Authorization 3.3.7. Outgoing <notification> Authorization
The <notification> message should be checked by the server to make The <notification> message MUST be checked by the server to make sure
sure no unauthorized data is contained within it. If so, the no unauthorized data is contained within it. If so, the restricted
restricted data must be removed from the message before it is sent to data MUST be removed from the message before it is sent to the
the client. 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
data it contains. data it contains.
The following figure shows the conceptual message processing model The following figure shows the conceptual message processing model
for outgoing <notification> messages. for outgoing <notification> messages.
skipping to change at page 30, line 33 skipping to change at page 30, line 33
list <data-rule>: Configures the access control rules for list <data-rule>: Configures the access control rules for
configuration datastore 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.
3.4.3. 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-netconf-acm YANG module imports typedefs from [RFC6021]. The ietf-netconf-acm YANG module imports typedefs from [RFC6021].
// RFC Ed.: please update the date to the date of publication // RFC Ed.: please update the date to the date of publication
<CODE BEGINS> file="ietf-netconf-acm@2011-02-03.yang" <CODE BEGINS> file="ietf-netconf-acm@2011-03-11.yang"
module ietf-netconf-acm { module ietf-netconf-acm {
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-acm"; namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-acm";
prefix "nacm"; prefix "nacm";
import ietf-yang-types { import ietf-yang-types {
prefix yang; prefix yang;
} }
organization organization
"IETF NETCONF (Network Configuration) Working Group"; "IETF NETCONF (Network Configuration) Working Group";
contact contact
"WG Web: <http://tools.ietf.org/wg/netconf/> "WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org> WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com> <mailto:mehmet.ersue@nsn.com>
WG Chair: Bert Wijnen WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net> <mailto:bertietf@bwijnen.net>
Editor: Andy Bierman Editor: Andy Bierman
<mailto:andy.bierman@brocade.com> <mailto:andy.bierman@brocade.com>
Editor: Martin Bjorklund Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>"; <mailto:mbj@tail-f.com>";
description description
"NETCONF Server Access Control Model. "NETCONF Server Access Control Model.
Copyright (c) 2011 IETF Trust and the persons identified as Copyright (c) 2011 IETF Trust and the persons identified as
authors of the code. All rights reserved. authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD to the license terms contained in, the Simplified BSD
License set forth in Section 4.c of the IETF Trust's License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices."; the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and // RFC Ed.: replace XXXX with actual RFC number and
// remove this note // remove this note
// RFC Ed.: remove this note // RFC Ed.: remove this note
// Note: extracted from draft-ietf-netconf-access-control-02.txt // Note: extracted from draft-ietf-netconf-access-control-03.txt
// RFC Ed.: please update the date to the date of publication // RFC Ed.: please update the date to the date of publication
revision "2011-02-03" { revision "2011-03-11" {
description description
"Initial version"; "Initial version";
reference reference
"RFC XXXX: Network Configuration Protocol "RFC XXXX: Network Configuration Protocol
Access Control Model"; Access Control Model";
} }
/* /*
* Extension statements * Extension statements
*/ */
extension secure { extension secure {
description description
"Used to indicate that the data model node "Used to indicate that the data model node
represents a sensitive security system parameter. represents a sensitive security system parameter.
If present, the NETCONF server will only allow If present, and the NACM module is enabled
the designated 'superuser' to have write or execute (i.e., /nacm/enable-nacm object equals 'true'),
default nacm-rights-type for the node. An explicit access the NETCONF server will only allow
control rule is required for all other users. 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, The 'secure' extension MAY appear within a data, rpc,
or notification node definition. It is ignored or notification node definition. It is ignored
otherwise."; otherwise.";
} }
extension very-secure { extension very-secure {
description description
"Used to indicate that the data model node "Used to indicate that the data model node
controls a very sensitive security system parameter. controls a very sensitive security system parameter.
If present, the NETCONF server will only allow If present, and the NACM module is enabled
the designated 'superuser' to have read, write, or execute (i.e., /nacm/enable-nacm object equals 'true'),
default nacm-rights-type for the node. An explicit access the NETCONF server will only allow
control rule is required for all other users. the designated 'superuser' to have read, write, or execute
default nacm-rights-type for the node. An explicit access
control rule is required for all other users.
The 'very-secure' extension may appear within a data, rpc, The 'very-secure' extension MAY appear within a data, rpc,
or notification node definition. It is ignored or notification node definition. It is ignored
otherwise."; otherwise.";
} }
/* /*
* 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 description
"General Purpose User Name string."; "General Purpose User Name string.";
} }
typedef nacm-matchall-string-type {
type string {
pattern "\*";
}
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-matchall-string-type { typedef nacm-rights-type {
type string { type union {
pattern "\*"; type nacm-matchall-string-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 { type bits {
type union { bit create {
type nacm-matchall-string-type; description
"Create access allowed to all specified data.
Any protocol operation that creates a
new instance of the specified data is a create
operation.";
}
bit read {
description
"Read access allowed to all specified data.
Any protocol operation or notification that
returns data to an application is a read
operation.";
}
bit update {
description
"Update access allowed to all specified data.
Any protocol operation that alters an existing
data node is an update operation.";
}
bit delete {
description
"Delete access allowed to all specified data.
Any protocol operation that removes a datastore
node instance is a delete operation.";
}
bit exec {
description
"Execution access to the specified RPC operation.
Any RPC operation invocation is an exec operation.";
}
}
}
description
"NETCONF Access 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.";
}
type bits { typedef nacm-group-name-type {
bit create { type string {
description length "1..max";
"Create access allowed to all specified data. pattern "[^\*].*";
Any protocol operation that creates a }
new instance of the specified data is a create description
operation."; "Name of administrative group that can be
} assigned to the user, and specified in
bit read { an access control rule.";
description }
"Read access allowed to all specified data.
Any protocol operation or notification that
returns data to an application is a read
operation.";
}
bit update {
description
"Update access allowed to all specified data.
Any protocol operation that alters an existing
data node is an update operation.";
}
bit delete {
description
"Delete access allowed to all specified data.
Any protocol operation that removes a database
node instance is a delete operation.";
}
bit exec {
description
"Execution access to the specified RPC operation.
Any RPC operation invocation is an exec operation.";
}
}
}
description
"NETCONF Access 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-action-type {
type string { type enumeration {
length "1..max"; enum permit {
pattern "[^\*].*"; description
} "Requested action is permitted.";
description }
"Name of administrative group that can be enum deny {
assigned to the user, and specified in description
an access control rule."; "Requested action is denied.";
} }
}
description
"Action taken by the server when a particular
rule matches.";
}
typedef nacm-action-type { typedef schema-instance-identifier {
type enumeration { type yang:xpath1.0;
enum permit { description
description "Path expression used to represent a special
"Requested action is permitted."; schema-instance identifier string.
}
enum deny {
description
"Requested action is denied.";
}
}
description
"Action taken by the server when a particular
rule matches.";
}
typedef schema-instance-identifier { A schema-instance-identifier value is an
type yang:xpath1.0; unrestricted YANG instance-identifier expression.
description All the same rules as an instance-identifier apply
"Path expression used to represent a special except predicates for keys are optional. If a key
schema-instance identifier string. predicate is missing, then the schema-instance-identifier
represents all possible server instances for that key.
A schema-instance-identifier value is an This XPath expression is evaluated in the following context:
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: o The set of namespace declarations are those in scope on
the leaf element where this type is used.
o The set of namespace declarations are those in scope on o The set of variable bindings contains one variable,
the leaf element where this type is used. 'USER', which contains the name of user of the current
session.
o The set of variable bindings contains one variable, o The function library is the core function library, but
'USER', which contains the name of user of the current note that due to the syntax restrictions of an
session. instance-identifier, no functions are allowed.
o The function library is the core function library, but o The context node is the root node in the data tree.";
note that due to the syntax restrictions of an }
instance-identifier, no functions are allowed.
o The context node is the root node in the data tree."; container nacm {
} nacm:very-secure;
container nacm { description
nacm:very-secure; "Parameters for NETCONF Access Control Model.";
description leaf enable-nacm {
"Parameters for NETCONF Access Control Model."; 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 enable-nacm { leaf read-default {
type boolean; type nacm-action-type;
default true; default "permit";
description description
"Enable or disable all NETCONF access control "Controls whether read access is granted if
enforcement. If 'true', then enforcement no appropriate rule is found for a
is enabled. If 'false', then enforcement particular read request.";
is disabled."; }
}
leaf read-default { leaf write-default {
type nacm-action-type; type nacm-action-type;
default "permit"; default "deny";
description description
"Controls whether read access is granted if "Controls whether create, update, or delete access
no appropriate rule is found for a is granted if no appropriate rule is found for a
particular read request."; particular write 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 exec-default {
type nacm-action-type; type nacm-action-type;
default "permit"; default "permit";
description description
"Controls whether exec access is granted if no appropriate "Controls whether exec access is granted if no appropriate
rule is found for a particular RPC operation request."; rule is found for a particular RPC operation request.";
} }
leaf denied-rpcs { leaf denied-rpcs {
type yang:zero-based-counter32; type yang:zero-based-counter32;
config false; config false;
mandatory true; mandatory true;
description description
"Number of times an RPC operation request was denied "Number of times an RPC operation request was denied
since the server last restarted."; since the server last restarted.";
} }
leaf denied-data-writes { leaf denied-data-writes {
type yang:zero-based-counter32; type yang:zero-based-counter32;
config false; config false;
mandatory true; mandatory true;
description description
"Number of times a request to alter a data node "Number of times a request to alter a data node
was denied, since the server last restarted."; was denied, since the server last restarted.";
} }
container groups { container groups {
description description
"NETCONF Access Control Groups."; "NETCONF Access Control Groups.";
list group { list group {
key name; key name;
description description
"One NACM Group Entry."; "One NACM Group Entry.";
leaf name { leaf name {
type nacm-group-name-type; type nacm-group-name-type;
description description
"Group name associated with this entry."; "Group name associated with this entry.";
} }
leaf-list user-name { leaf-list user-name {
type nacm-user-name-type; type nacm-user-name-type;
description description
"Each entry identifies the user name of "Each entry identifies the user name of
a member of the group associated with a member of the group associated with
this entry."; this entry.";
} }
} }
} }
container rules {
description
"NETCONF Access Control Rules.";
grouping common-rule-parms { container rules {
description description
"Common rule parameters."; "NETCONF Access Control Rules.";
leaf rule-name { grouping common-rule-parms {
type string { description
length "1..256"; "Common rule parameters.";
}
description
"Arbitrary name assigned to the
access control rule.";
}
leaf allowed-rights { leaf rule-name {
type nacm-rights-type; type string {
description length "1..256";
"List of access rights granted to }
specified administrative groups for the description
content specified by the associated path."; "Arbitrary name assigned to the
} access control rule.";
}
leaf-list allowed-group { leaf allowed-rights {
type union { type nacm-rights-type;
type nacm-matchall-string-type; description
type nacm-group-name-type; "List of access rights granted to
} specified administrative groups for the
min-elements 1; content specified by the associated path.";
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 leaf-list allowed-group {
administrative groups apply to the entry."; type union {
} type nacm-matchall-string-type;
type nacm-group-name-type;
}
min-elements 1;
description
"List of administrative groups which will be
assigned the associated access rights
for the content specified by the associated path.
leaf nacm-action { The string '*' indicates that all configured
type nacm-action-type; administrative groups apply to the entry.";
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 { leaf nacm-action {
type string { type nacm-action-type;
length "1..4095"; mandatory true;
} description
description "The access control action associated with the
"A textual description of the access rule."; 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.";
}
list module-rule { leaf comment {
key "module-name rule-name"; type string {
ordered-by user; length "1..4095";
}
description
"A textual description of the access rule.";
}
}
description list module-rule {
"One Module Access Rule. key "module-name rule-name";
ordered-by user;
Rules are processed in user-defined order. A module rule description
is considered a match if the XML namespace for the "One Module Access Rule.
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 { Rules are processed in user-defined order. A module rule
type string; is considered a match if the XML namespace for the
description specified module name matches the XML namespace used
"Name of the module associated with this rule."; 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.";
uses common-rule-parms { leaf module-name {
refine allowed-rights { type string;
mandatory true; description
} "Name of the module associated with this rule.";
} }
}
list rpc-rule { uses common-rule-parms {
key "module-name rpc-name rule-name"; refine allowed-rights {
ordered-by user; mandatory true;
}
}
}
description list rpc-rule {
"One RPC Operation Access Rule. key "module-name rpc-name rule-name";
ordered-by user;
Rules are processed in user-defined order. An RPC rule is description
considered a match if the module name of the requested RPC "One RPC Operation Access Rule.
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.";
leaf module-name { Rules are processed in user-defined order. An RPC rule is
type string; considered a match if the module name of the requested RPC
description operation matches 'module-name', the requested RPC
"Name of the module defining this RPC operation."; 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.";
leaf rpc-name { leaf module-name {
type string; type string;
description description
"Name of the RPC operation."; "Name of the module defining this RPC operation.";
} }
uses common-rule-parms; leaf rpc-name {
} type string;
description
"Name of the RPC operation.";
}
list data-rule { uses common-rule-parms;
key "rule-name"; }
ordered-by user;
description list data-rule {
"One Data Access Control Rule. key "rule-name";
ordered-by user;
Rules are processed in user-defined order. A data rule is description
considered to match when the path expression identifies "One Data Access Control Rule.
the same node that is being accessed in the NETCONF
database, and the administrative group associated with the
session is identified in the 'allowed-group' leaf-list,
and the requested operation is included in the
'allowed-rights' leaf.";
leaf path { Rules are processed in user-defined order. A data rule is
type schema-instance-identifier; considered to match when the path expression identifies
mandatory true; the same node that is being accessed in the NETCONF
description datastore, and the administrative group associated with the
"Schema Instance Identifier associated with the data node session is identified in the 'allowed-group' leaf-list,
controlled by this rule. and the requested operation is included in the
'allowed-rights' leaf.";
Configuration data or state data instance identifiers leaf path {
start with a top-level data node. A complete instance type schema-instance-identifier;
identifier is required for this type of path value. mandatory true;
description
"Schema Instance Identifier associated with the data node
controlled by this rule.
The special value '/' refers to all possible database Configuration data or state data instance identifiers
contents."; start with a top-level data node. A complete instance
} identifier is required for this type of path value.
uses common-rule-parms { The special value '/' refers to all possible datastore
refine allowed-rights { contents.";
mandatory true; }
}
}
}
list notification-rule { uses common-rule-parms {
key "module-name refine allowed-rights {
notification-name mandatory true;
rule-name"; }
ordered-by user; }
}
description list notification-rule {
"One Notification Access Rule. key "module-name
notification-name
rule-name";
ordered-by user;
A notification is considered a match if the module name of description
the requested event type matches "One Notification Access Rule.
'module-name', the requested event type
matches the 'notification-name', and the administrative
group associated with the requesting session is listed in
the 'allowed-group' leaf-list. If the 'allowed-rights'
leaf is present, it is ignored by the server.
Only the 'read' bit can possibly cause
a match for a notification rule.";
leaf module-name { A notification is considered a match if the module name of
type string; the requested event type matches
description 'module-name', the requested event type
"Name of the module defining this matches the 'notification-name', and the administrative
notification event type."; group associated with the requesting session is listed in
} the 'allowed-group' leaf-list. If the 'allowed-rights'
leaf is present, it is ignored by the server.
Only the 'read' bit can possibly cause
a match for a notification rule.";
leaf notification-name { leaf module-name {
type string; type string;
description description
"Name of the notification event."; "Name of the module defining this
} notification event type.";
}
uses common-rule-parms; leaf notification-name {
} type string;
} description
"Name of the notification event.";
}
} uses common-rule-parms;
} }
}
}
}
<CODE ENDS> <CODE ENDS>
Figure 5 Figure 5
3.5. 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-netconf-acm URI: urn:ietf:params:xml:ns:yang:ietf-netconf-acm
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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.
This document incorporates the optional use of a 'superuser' account, This document incorporates the optional use of a 'superuser' account,
which can be used to bypass access control enforcement. It is which can be used to bypass access control enforcement. It is
suggested that the 'root' account not be used for NETCONF over SSH suggested that the 'root' account not be used for NETCONF over SSH
servers, because 'root' SSH logins should be disabled in the SSH servers, because 'root' SSH logins SHOULD be disabled in the SSH
server. server.
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 protocol operations There is a risk that invocation of non-standard protocol operations
will have undocumented side effects. An administrator should will have undocumented side effects. An administrator needs to
construct access control rules such that the configuration datastore construct access control rules such that the configuration datastore
is protected from such side effects. Also, such protocol operations is protected from such side effects. Also, such protocol operations
should never be invoked by a session using the 'superuser' SHOULD never be invoked by a session using the 'superuser'
administrative user. administrative user.
There is a risk that non-standard protocol 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 needs to 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 needs to 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
the data model defined in this document. the data model defined in this document.
If write access is allowed for configuration of access control rules, If write access is allowed for configuration of access control rules,
then care must be taken not to disrupt the access control then care needs to be taken not to disrupt the access control
enforcement. enforcement.
An administrator should restrict read access to the following objects An administrator needs to restrict read access to the following
within this data model, which reveal access control configuration objects within this data model, which reveal access control
which could be considered sensitive. configuration which could be considered sensitive.
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
4. References 4. References
4.1. Normative References 4.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
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[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020, Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010. October 2010.
[RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021, [RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
October 2010. October 2010.
[I-D.ietf-netconf-4741bis] [I-D.ietf-netconf-4741bis]
Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)", Bierman, "Network Configuration Protocol (NETCONF)",
draft-ietf-netconf-4741bis-07 (work in progress), draft-ietf-netconf-4741bis-09 (work in progress),
January 2011. February 2011.
[I-D.ietf-netconf-rfc4742bis] [I-D.ietf-netconf-rfc4742bis]
Wasserman, M. and T. Goddard, "Using the NETCONF Wasserman, M. and T. Goddard, "Using the NETCONF
Configuration Protocol over Secure Shell (SSH)", Configuration Protocol over Secure Shell (SSH)",
draft-ietf-netconf-rfc4742bis-06 (work in progress), draft-ietf-netconf-rfc4742bis-07 (work in progress),
January 2011. February 2011.
4.2. Informative References 4.2. Informative References
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)", "Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000. RFC 2865, June 2000.
[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In [RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In
User Service (RADIUS) Authorization for Network Access User Service (RADIUS) Authorization for Network Access
Server (NAS) Management", RFC 5607, July 2009. Server (NAS) Management", RFC 5607, July 2009.
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 needs to 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-netconf-acm"> <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
<groups> <groups>
<group> <group>
<name>admin</name> <name>admin</name>
<user-name>admin</user-name> <user-name>admin</user-name>
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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. Change Log Appendix B. Change Log
-- RFC Ed.: remove this section before publication. -- RFC Ed.: remove this section before publication.
B.1. 01-02 B.1. 02-03
Fixed improper usage of RFC 2119 keywords.
Changed term usage of 'database' to 'datastore'.
Clarified that 'secure' and 'very-secure' extensions only apply if
the /nacm/enable-nacm object is 'true'.
B.2. 01-02
Removed authentication text and objects. Removed authentication text and objects.
Changed module name from ietf-nacm to ietf-netconf-acm. Changed module name from ietf-nacm to ietf-netconf-acm.
Updated NETCONF and YANG terminology. Updated NETCONF and YANG terminology.
Removed open issues section. Removed open issues section.
Changed some must to MUST in requirements section. Changed some must to MUST in requirements section.
B.2. 00-01 B.3. 00-01
Updated YANG anf YANG Types references. Updated YANG anf YANG Types references.
Updated module namespace URI to standard format. Updated module namespace URI to standard format.
Updated module header meta-data to standard format. Updated module header meta-data to standard format.
Filled in IANA section. Filled in IANA section.
B.3. 00 B.4. 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
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