



I2RS working group                                              S. Hares
Internet-Draft                                                    Huawei
Intended status: Informational                                D. Migault
Expires: April 2, 2017                                        J. Halpern
                                                                Ericsson
                                                      September 29, 2016


                   I2RS Security Related Requirements
           draft-ietf-i2rs-protocol-security-requirements-17

Abstract

   This presents security-related requirements for the I2RS protocol
   which provides a new interface to the routing system described in the
   I2RS architecture document (RFC7921).  The I2RS protocol is a re-use
   protocol implemented by re-using portions of existing IETF protocols
   and adding new features to these protocols.  The I2RS protocol re-
   uses security features of a secure transport (E.g.  TLS, SSH, DTLS)
   such as encryption, message integrity, mutual peer authentication,
   and replay protection.  The new I2RS features to consider from a
   security perspective are: a priority mechanism to handle multi-headed
   write transactions, an opaque secondary identifier which identifies
   an application using the I2RS client, and an extremely constrained
   read-only non-secure transport.  This document provides the detailed
   requirements for these security features.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

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

   This Internet-Draft will expire on April 2, 2017.








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Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
     2.2.  Security Definitions  . . . . . . . . . . . . . . . . . .   4
     2.3.  I2RS Specific Definitions . . . . . . . . . . . . . . . .   5
   3.  Security Features and Protocols: Re-used and New  . . . . . .   7
     3.1.  Security Protocols Re-Used by the I2RS Protocol . . . . .   7
     3.2.  New Features Related to Security  . . . . . . . . . . . .   8
     3.3.  I2RS Protocol Security Requirements vs. IETF Management
           Protocols . . . . . . . . . . . . . . . . . . . . . . . .   9
   4.  Security-Related Requirements . . . . . . . . . . . . . . . .  10
     4.1.  I2RS Peers(agent and client) Identity Authentication  . .  10
     4.2.  Identity Validation Before Role-Based Message Actions . .  11
     4.3.  Peer Identity, Priority, and Client Redundancy  . . . . .  12
     4.4.  Multi-Channel Transport: Secure Transport and Insecure
           Transport . . . . . . . . . . . . . . . . . . . . . . . .  13
     4.5.  Management Protocol Security  . . . . . . . . . . . . . .  15
     4.6.  Role-Based Data Model Security  . . . . . . . . . . . . .  16
     4.7.  Security of the environment . . . . . . . . . . . . . . .  17
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   7.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .  18
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  18
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20








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1.  Introduction

   The Interface to the Routing System (I2RS) provides read and write
   access to information and state within the routing system.  An I2RS
   client interacts with one or more I2RS agents to collect information
   from network routing systems.  [RFC7921] describes the architecture
   of this interface, and this documents assumes the reader is familiar
   with this architecture and its definitions.  Section 2 highlights
   some of the references the reader is required to be familiar with.

   The I2RS interface is instantiated by the I2RS protocol connecting an
   I2RS client and an I2RS agent associated with a routing system.  The
   I2RS protocol is a re-use protocol implemented by re-using portions
   of existing IETF protocols, and adding new features to these
   protocols.  As a re-use protocol, it can be considered a higher-level
   protocol since it can be instantiated in multiple management
   protocols (e.g.  NETCONF [RFC6241] or RESTCONF
   [I-D.ietf-netconf-restconf]) operating over a secure transport.  The
   security for the I2RS protocol comes from the management protocols
   operating over a a secure transport.

   This document is part of the requirements for I2RS protocol which
   also include:

   o  I2RS architecture [RFC7921],

   o  I2RS ephemeral state requirements [I-D.ietf-i2rs-ephemeral-state],

   o  publication/subscription requirements [RFC7922], and

   o  traceability [RFC7923].

   Since the I2RS "higher-level" protocol changes the interface to the
   routing systems, it is important that implementers understand the new
   security requirements for the environment the I2RS protocol operates
   in.  These security requirements for the I2RS environment are
   specified in [I-D.ietf-i2rs-security-environment-reqs]; and the
   summary of the I2RS protocol security environment is found in the
   I2RS Architecture [RFC7920].

   I2RS reuses the secure transport protocols (TLS, SSH, DTLS) which
   support encryption, message integrity, peer authentication, and key
   distribution protocols.  Optionally, implementers may utilize AAA
   protocols (Radius over TLS or Diameter over TLS) to securely
   distribute identity information.

   Section 3 provides an overview of security features and protocols
   being re-used (section 3.1) and the new security features being



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   required (section 3.2).  Section 3 also explores how existing and new
   security features and protocols would be paired with existing IETF
   management protocols (section 3.3).

   The new features I2RS extends to these protocols are a priority
   mechanism to handle multi-headed writes, an opaque secondary
   identifier to allow traceability of an application utilizing a
   specific I2RS client to communicate with an I2RS agent, and insecure
   transport constrained to be utilized only for read-only data, which
   may include publically available data (e.g. public BGP Events, public
   telemetry information, web service availability) and some legacy
   data.

   Section 4 provides the I2RS protocol security requirements by the
   following security features:

   o  peer identity authentication (section 4.1),

   o  peer identity validation before role-based message actions
      (section 4.2)

   o  peer identity and client redundancy (section 4.3),

   o  multi-channel transport requirements: Secure transport and
      insecure Transport (section 4.4),

   o  management protocol security requirements (section 4.5),

   o  role-based security (section 4.6),

   o  security environment (section 4.7)

   Protocols designed to be I2RS higher-layer protocols need to fulfill
   these security requirements.

2.  Definitions

2.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.2.  Security Definitions

   This document utilizes the definitions found in the following
   documents: [RFC4949] and [RFC7921]




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   Specifically, this document utilizes the following definitions from
   [RFC4949]:

   o  access control,

   o  authentication,

   o  data confidentiality,

   o  data integrity,

   o  data privacy,

   o  identity,

   o  identifier,

   o  mutual authentication,

   o  role,

   o  role-based access control,

   o  security audit trail, and

   o  trust.

   [RFC7922] describes traceability for I2RS interface and the I2RS
   protocol.  Traceability is not equivalent to a security audit trail
   or simple logging of information.  A security audit trail may utilize
   traceability information.

   This document also requires that the user is familiar with the
   pervasive security requirements in [RFC7258].

2.3.  I2RS Specific Definitions

   The document utilizes the following concepts from the I2RS
   architecture: [RFC7921]:

   o  I2RS client, I2RS agent, and I2RS protocol (section 2),

   o  I2RS higher-layer protocol (section 7.2)

   o  scope: read scope, notification scope, and write scope (section
      2),

   o  identity and scope of the identity (section 2),



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   o  roles or security rules (section 2),

   o  identity and scope, and secondary identity (section 2),

   o  routing system/subsytem (section 2),

   o  I2RS assumed security environment (section 4),

   o  I2RS identity and authorization (section 4.1),

   o  I2RS authorization, scope of Authorization in I2RS client and
      agent (section 4.2),

   o  client redundancy with a single client identity (section 4.3),

   o  restrictions on I2RS in personal devices (section 4.4),

   o  communication channels and I2RS high-layer protocol (section 7.2),

   o  active communication versus connectivity (section 7.5),

   o  multi-headed control (section 7.8), and

   o  transaction, message, multi-message atomicity (section 7.9).

   This document assumes the reader is familar with these terms.

   This document discusses the security of the multiple I2RS
   communication channels which operate over the higher-layer I2RS
   protocol.  The higher-layer I2RS protocol combines a secure transport
   and I2RS contextual information, and re-uses IETF protocols and data
   models to create the secure transport and the I2RS data-model driven
   contextual information.  To describe how the I2RS high-layer protocol
   combines other protocols into the I2RS higher-layer protocol, the
   following terms are used:

   I2RS component protocols

      Protocols which are re-used and combined to create the I2RS
      protocol.

   I2RS secure-transport component protocols

      The I2RS secure transport protocols that support the I2RS higher-
      layer protocol.

   I2RS management component protocols




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      The I2RS management protocol which provide the management
      information context.

   I2RS AAA component protocols

      The I2RS AAA protocols supporting the I2RS higher-layer protocol.

   The I2RS higher-layer protocol requires implementation of a I2RS
   secure-transport component protocol and the I2RS management component
   protocol.  The I2RS AAA component protocol is optional.

3.  Security Features and Protocols: Re-used and New

3.1.  Security Protocols Re-Used by the I2RS Protocol

   I2RS requires a secure transport protocol and key distribution
   protocols.  The secure transport features required by I2RS are peer
   authentication, confidentiality, data integrity, and replay
   protection for I2RS messages.  According to
   [I-D.ietf-taps-transports], the secure transport protocols which
   support peer authentication, confidentiality, data integrity, and
   replay protection are the following:

   1.  TLS [RFC5246] over TCP or SCTP,

   2.  DTLS over UDP with replay detection and anti-DoS stateless cookie
       mechanism required for the I2RS protocol, and the I2RS protocol
       allow DTLS options of record size negotiation and and conveyance
       of "don't" fragment bits to be optional in deployments.

   3.  HTTP over TLS (over TCP or SCTP), and

   4.  HTTP over DTLS (with the requirements and optional features
       specified above in item 2).

   The following protocols would need to be extended to provide
   confidentiality, data integrity, peer authentication, and key
   distribution protocols: IPFIX (over SCTP, TCP or UDP) and ForCES TML
   layer (over SCTP).  These protocols will need extensions to run over
   a secure transport (TLS or DTLS) (see section 3.3 for details).

   The specific type of key management protocols an I2RS secure
   transport uses depends on the transport.  Key management protocols
   utilized for the I2RS protocols SHOULD support automatic rotation.

   An I2RS implementer may use AAA protocols over secure transport to
   distribute the identities for I2RS client and I2RS agent and role
   authorization information.  Two AAA protocols are: Diameter [RFC6733]



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   and Radius [RFC2865].  To provide the best security I2RS peer
   identities, the AAA protocols MUST be run over a secure transport
   (Diameter over secure transport (TLS over TCP) [RFC6733]), Radius
   over a secure transport (TLS) [RFC6614]).

3.2.  New Features Related to Security

   The new features are priority, an opaque secondary identifier, and an
   insecure protocol for read-only data constrained to specific standard
   usages.  The I2RS protocol allows multi-headed control by several
   I2RS clients.  This multi-headed control is based on the assumption
   that the operator deploying the I2RS clients, I2RS agents, and the
   I2rs protocol will coordinate the read, write, and notification scope
   so the I2RS clients will not contend for the same write scope.
   However, just in case there is an unforseen overlap of I2RS clients
   attempting to write a particular piece of data, the I2RS architecture
   [RFC7921] provides the concept of each I2RS client having a priority.
   The I2RS client with the highest priority will have its write
   succeed.  This document specifies requirements for this new concept
   of priority.

   The opaque secondary identifier identifies an application which is
   using the I2RS client to I2RS agent communication to manage the
   routing system.  The secondary identifier is opaque to the I2RS
   protocol.  In order to protect personal privacy, the secondary
   identifier should not contain personal identifiable information.

   The last new feature related to I2RS security is the ability to allow
   non-confidential data to be transferred over a non-secure transport.
   It is expected that most I2RS data models will describe information
   that will be transferred with confidentiality.  Therefore, any model
   which transfers data over a non-secure transport is marked.  The use
   of a non-secure transport is optional, and an implementer SHOULD
   create knobs that allow data marked as non-confidential to be sent
   over a secure transport.

   Non-confidential data can only be read or notification scope
   transmission of events.  Non-confidential data cannot be write scope
   or notification scope configuration.  An example of non-confidential
   data is the telemetry information that is publically known (e.g.  BGP
   route-views data or web site status data) or some legacy data (e.g.
   interface) which cannot be transported in secure transport.  The IETF
   I2RS Data models MUST indicate in the data model the specific data
   which is non-confidential.

   Most I2RS data models will expect that the information described in
   the model will be transferred with confidentiality.




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3.3.  I2RS Protocol Security Requirements vs. IETF Management Protocols

   Table 1 below provides a partial list of the candidate management
   protocols and the secure transports each one of the support.  One
   column in the table indicates the transport protocol will need I2RS
   security extensions.

      Mangement
      Protocol   Transport Protocol      I2RS Extensions
      =========  =====================   =================
      NETCONF     TLS over TCP (*1)      None required (*2)

      RESTCONF   HTTP over TLS with      None required (*2)
                 X.509v3 certificates,
                 certificate validation,
                 mutual authentication:
                 1) authenticated
                    server identity,
                 2) authenticated
                   client identity
                (*1)

      FORCES    TML over SCTP           Needs extension to
                (*1)                    TML to run TML over
                                        TLS over SCTP, or
                                        DTLS with options for
                                        replay protection
                                        and anti-DoS stateless
                                        cookie mechanism.
                                        (DTLS record size
                                        negotiation and conveyance
                                        of "don't" fragment
                                        bits are optional).
                                       The IPSEC mechanism is
                                       not sufficient for
                                       I2RS traveling over
                                       multiple hops
                                       (router + link) (*2)

      IPFIX     SCTP, TCP, UDP         Needs to extension
                TLS or DTLS for        to support TLS or
                secure client (*1)     DTLS with options for
                                       replay protection
                                       and anti-DoS stateless
                                       cookie mechanism.
                                       (DTLS record size
                                       negotiation and conveyance
                                       of "don't" fragment



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                                       bits are optional).


       *1 - Key management protocols
        MUST support appropriate key rotation.


       *2 - Identity and Role authorization distributed
       by Diameter or Radius MUST use Diameter over TLS
       or Radius over TLS.

4.  Security-Related Requirements

   This section discusses security requirements based on the following
   security functions:

   o  peer identity authentication (section 4.1),

   o  Peer Identity validation before Role-based Message Actions
      (section 4.2)

   o  peer identity and client redundancy (section 4.3),

   o  multi-channel transport requirements: Secure transport and
      insecure Transport (section 4.4),

   o  management protocol security requirements (section 4.5),

   o  role-based security (section 4.6),

   o  security environment (section 4.7)

   The I2RS Protocol depends upon a secure transport layer for peer
   authentication, data integrity, confidentiality, and replay
   protection.  The optional insecure transport can only be used
   restricted set of publically data available (events or information)
   or a select set of legacy data.  Data passed over the insecure
   transport channel MUST NOT contain any data which identifies a
   person.

4.1.  I2RS Peers(agent and client) Identity Authentication

   The following requirements specify the security requirements for Peer
   Identity Authentication for the I2RS protocol:

   o  SEC-REQ-01: All I2RS clients and I2RS agents MUST have an
      identity, and at least one unique identifier that uniquely
      identifies each party in the I2RS protocol context.



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   o  SEC-REQ-02: The I2RS protocol MUST utilize these identifiers for
      mutual identification of the I2RS client and I2RS agent.

   o  SEC-REQ-03: Identifier distribution and the loading of these
      identifiers into I2RS agent and I2RS client SHOULD occur outside
      the I2RS protocol prior to the I2RS protocol establishing a
      connection between I2RS client and I2RS agent.  AAA protocols MAY
      be used to distribute these identifiers, but other mechanism can
      be used.

   Explanation:

   These requirements specify the requirements for I2RS peer (I2RS agent
   and I2RS client) authentication.  A secure transport (E.g.  TLS) will
   authenticate based on these identities, but these identities are
   identities for the I2RS management layer.  An AAA protocol
   distributing I2RS identity information SHOULD transport its
   information over a secure transport.

4.2.  Identity Validation Before Role-Based Message Actions

   The requirements for I2RS clients with Secure Connections are the
   following:

      SEC-REQ-04: An I2RS agent receiving a request from an I2RS client
      MUST confirm that the I2RS client has a valid identity.

      SEC-REQ-05: An I2RS client receiving an I2RS message over a secure
      transport MUST confirm that the I2RS agent has a valid identifier.

      SEC-REQ-06: An I2RS agent receiving an I2RS message over an
      insecure transport MUST confirm that the content is suitable for
      transfer over such a transport.

   Explanation:

   Each I2RS client has a scope based on its identity and the security
   roles (read, write, or events) associated with that identity, and
   that scope must be considered in processing an I2RS messages sent on
   a communication channel.  An I2RS communication channel may utilize
   multiple transport sessions, or establish a transport session and
   then close the transport session.  Therefore, it is important that
   the I2RS peers are operating utilizing valid peer identities when a
   message is processed rather than checking if a transport session
   exists.

   During the time period when a secure transport session is active, the
   I2RS agent SHOULD assume that the I2RS client's identity remains



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   valid.  Similarly, while a secure connection exists that included
   validating the I2RS agent's identity and a message is received via
   that connection, the I2RS client SHOULD assume that the I2RS agent's
   identity remains valid.

   The definition of what constitutes a valid identity or a valid
   identifier MUST be defined by the I2RS protocol.

4.3.  Peer Identity, Priority, and Client Redundancy

   Requirements:

      SEC-REQ-07: Each I2RS Identifier MUST be associated with just one
      priority.

      SEC-REQ-08: Each Identifier is associated with one secondary
      identifier during a particular I2RS transaction (e.g. read/write
      sequence), but the secondary identifier may vary during the time a
      connection between the I2RS client and I2RS agent is active.

   Explanation:

   The I2RS architecture also allows multiple I2RS clients with unique
   identities to connect to an I2RS agent (section 7.8).  The I2RS
   deployment using multiple clients SHOULD coordinate this multi-headed
   control of I2RS agents by I2RS clients so no conflict occurs in the
   write scope.  However, in the case of conflict on a write scope
   variable, the error resolution mechanisms defined by the I2RS
   architecture multi-headed control ([RFC7921], section 7.8) allow the
   I2RS agent to deterministically choose one I2RS client.  The I2RS
   client with highest priority is given permission to write the
   variable, and the second client receives an error message.

   A single I2RS client may be associated with multiple applications
   with different tasks (e.g. weekly configurations or emergency
   configurations).  The secondary identity is an opaque value that the
   I2RS client passes to the I2RS agent so that this opaque value can be
   placed in the tracing file or event stream to identify the
   application using the I2RS client to I2RS agent communication.  The
   I2RS client is trusted to simply assert the secondary identifier.

   One example of the use of the secondary identity is the situation
   where an operator of a network has two applications that use an I2RS
   client.  The first application is a weekly configuration application
   that uses the I2RS protocol to change configurations.  The second
   application is an application that allows operators to makes
   emergency changes to routers in the network.  Both of these
   applications use the same I2RS client to write to an I2RS agent.  In



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   order for traceability to determine which application (weekly
   configuration or emergency) wrote some configuration changes to a
   router, the I2RS client sends a different opaque value for each of
   the applications.  The weekly configuration secondary opaque value
   could be "xzzy-splot" and the emergency secondary opaque value could
   be "splish-splash".

   A second example is if the I2RS client is used for monitoring of
   critical infrastructure.  The operator of a network using the I2RS
   client may desire I2RS client redundancy where the monitoring
   application wth the I2RS client is deployed on two different boxes
   with the same I2RS client identity (see [RFC7921] section 4.3) These
   two monitoring applications pass to the I2RS client whether the
   application is the primary or back up application, and the I2RS
   client passes this information in the I2RS secondary identitifier as
   the figure below shows.  The primary applications secondary
   identifier is "primary-monitoring", and the backup application
   secondary identifier is "backup-monitoring".  The I2RS tracing
   information will include the secondary identifier information along
   with the transport information in the tracing file in the agent.

   Example 2: Primary and Backup Application for Monitoring
              Identification sent to agent


   Application A--I2RS client--Secure transport(#1)
    [I2RS identity 1, secondary identifier: "primary-monitoring"]-->

   Application B--I2RS client--Secure transport(#2)
    [I2RS identity 1, secondary identifier: "backup-monitoring"]-->

    Figure 1


4.4.  Multi-Channel Transport: Secure Transport and Insecure Transport

   Requirements:

      SEC-REQ-09: The I2RS protocol MUST be able to transfer data over a
      secure transport and optionally MAY be able to transfer data over
      a non-secure transport.  The default transport is a secure
      transport, and this secure transport is mandatory to implement
      (MTI) in all I2RS agents, and in any I2RS client which: a)
      performs a Write scope transaction which is sent to the I2RS agent
      or b): configures an Event Scope transaction.  This secure
      transport is mandatory to use (MTU) on any I2RS client's Write
      transaction or the configuration of an Event Scope transaction.




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      SEC-REQ-10: The secure transport MUST provide data
      confidentiality, data integrity, and practical replay prevention.

      SEC-REQ-11: The I2RS client and I2RS agent protocol SHOULD
      implement mechanisms that mitigate DoS attacks.  For the secure
      transport, this means the secure transport must support DoS
      prevention.  For the insecure transport protocol, the I2RS higher-
      layer protocol MUST contain a transport management layer that
      considers the detection of DoS attacks and provides a warning over
      a secure-transport channel.

      SEC-REQ-12: A secure transport MUST be associated with a key
      management solution that can guarantee that only the entities
      having sufficient privileges can get the keys to encrypt/decrypt
      the sensitive data.

      SEC-REQ-13: A machine-readable mechanism to indicate that a data-
      model contains non-confidential data MUST be provided.  A non-
      secure transport MAY be used to publish only read scope or
      notification scope data if the associated data model indicates
      that that data is non-confidential.

      SEC-REQ-14: The I2RS protocol MUST be able to support multiple
      secure transport sessions providing protocol and data
      communication between an I2RS agent and an I2RS client.  However,
      a single I2RS agent to I2RS client connection MAY elect to use a
      single secure transport session or a single non-secure transport
      session conforming the requirements above.

      SEC-REQ-15: Deployment configuration knobs SHOULD be created to
      allow operators to send "non-confidential" Read scope (data or
      Event streams) over a secure transport.

      SEC-REQ-16: The I2RS protocol makes use of both secure and
      insecure transports, but this use MUST NOT be done in any way that
      weakens the secure transport protocol used in the I2RS protocol or
      other contexts that do not have this requirement for mixing secure
      and insecure modes of operation.

   Explanation:

   The I2RS architecture defines three scopes: read, write, and
   notification scope.  Insecure data can only be used for read scope
   and notification scope of "non-confidential data".  The configuration
   of ephemeral data in the I2RS agent uses either write scope for data
   or write scope for configuration of event notification streams.  The
   requirement to use secure transport for configuration prevents




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   accidental or malevolent entities from altering the I2RS routing
   system through the I2RS agent.

   It is anticipated that the passing of most I2RS ephemeral state
   operational status SHOULD be done over a secure transport.

   In most circumstances the secure transport protocol will be
   associated with a key management system.  Most deployments of the
   I2RS protocol will allow for automatic key management systems.  Since
   the data models for the I2RS protocol will control key routing
   functions, it is important that deployments of I2RS use automatic key
   management systems.

   Per BCP107 [RFC4107] while key management system SHOULD be automatic,
   the systems MAY be manual in the following scenarios:

      a) The environment has limited bandwidth or high round-trip times.

      b) The information being protected has low value.

      c) The total volume of traffic over the entire lifetime of the
      long-term session key will be very low.

      d) The scale of the deployment is limited.

   Operators deploying the I2RS protocol selecting manual key management
   SHOULD consider both short and medium term plans.  Deploying
   automatic systems initially may save effort over the long-term.

4.5.  Management Protocol Security

   Requirements:

      SEC-REQ-17: In a critical infrastructure, certain data within
      routing elements is sensitive and read/write operations on such
      data SHOULD be controlled in order to protect its confidentiality.
      To achieve this, higher-layer protocols MUST utilize a secure
      transport, and SHOULD provide access control functions to protect
      confidentiality of the data.

      SEC-REQ-18: An integrity protection mechanism for I2RS MUST be
      provided that will be able to ensure the following:

         1) the data being protected is not modified without detection
         during its transportation,

         2) the data is actually from where it is expected to come from,
         and



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         3) the data is not repeated from some earlier interaction the
         higher layer protocol (best effort).

      The I2RS higher-layer protocol operating over a secure transport
      provides this integrity.  The I2RS higher-layer protocol operating
      over an insecure transport SHOULD provide some way for the client
      receiving non-confidential read-scoped or event-scoped data over
      the insecure connection to detect when the data integrity is
      questionable; and in the event of a questionable data integrity
      the I2RS client should disconnect the insecure transport
      connection.

      SEC-REQ-19: The I2RS higher-layer protocol MUST provide a
      mechanism for message traceability (requirements in [RFC7922])
      that supports the tracking higher-layer functions run across
      secure connection or a non-secure transport.

   Explanation:

   Most carriers do not want a router's configuration and data flow
   statistics known by hackers or their competitors.  While carriers may
   share peering information, most carriers do not share configuration
   and traffic statistics.  To achieve this, the I2RS higher-layer
   protocol (e.g NETCONF) requires access control (NACM [RFC6536]) for
   sensitive data needs to be provided; and the confidentiality
   protection on such data during transportation needs to be enforced.

   Integrity of data is important even if the I2RS protocol is sending
   non-confidential data over an insecure connection.  The ability to
   trace I2RS protocol messages that enact I2RS transactions provides a
   minimal aid to helping operators check how messages enact
   transactions on a secure or insecure transport.  Contextual checks on
   specific non-confidential data sent over a insecure connection may
   indicate the data has been modified.

4.6.  Role-Based Data Model Security

   The I2RS Architecture [RFC7921] specifies access control by "role"
   where role is a method of making access control more manageable by
   creating a grouping of users so that access control can be specified
   for a role rather than for each of the individuals.  Therefore, I2RS
   role specifies the access control for a group as being read, write,
   or notification.

      SEC-REQ-20: The rules around what I2RS security role is permitted
      to access and manipulate what information over a secure transport
      (which protects the data in transit) SHOULD ensure that data of
      any level of sensitivity is reasonably protected from being



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      observed by those without permission to view it, so that privacy
      requirements are met.

      SEC-REQ-21: Role security MUST work when multiple transport
      connections are being used between the I2RS client and I2RS agent
      as the I2RS architecture [RFC7921] describes.

      Sec-REQ-22: If an I2RS agents or an I2RS client is tightly
      correlated with a person, then the I2RS protocol and data models
      SHOULD provide additional security that protects the person's
      privacy.

   Explanation:

   I2RS higher-layer uses management protocol E.g.  NETCONF, RESTCONF)
   to pass messages in order to enact I2RS transactions.  Role Security
   must secure data (sensitivity and normal data) in a router even when
   it is operating over multiple connections at the same time.  NETCONF
   can run over TLS (over TCP or SCTP) or SSH.  RESTCONF runs over HTTP
   over a secure transport (TLS).  SCTP [RFC4960] provides security for
   multiple streams plus end-to-end transport of data.  Some I2RS
   functions may wish to operate over DTLS which runs over UDP
   ([RFC6347]), DDCP ([RFC6238]), and SCTP ([RFC5764]).

   Please note the security of the application to I2RS client connection
   is outside of the I2RS protocol or I2RS interface.

   While I2RS clients are expected to be related to network devices and
   not individual people, if an I2RS client ran on a person's phone,
   then privacy protection to anonymize any data relating to a person's
   identity or location would be needed.

   A variety of forms of managemen may set policy on roles: "operator-
   applied knobs", roles that restrict personal access, data-models with
   specific "privacy roles", and access filters.

4.7.  Security of the environment

   The security for the implementation of a protocol also considers the
   protocol environment.  The environmental security requirements are
   found in: [I-D.ietf-i2rs-security-environment-reqs].

5.  Security Considerations

   This is a document about security requirements for the I2RS protocol
   and data modules.  Security considerations for the I2RS protocol
   include both the protocol and the security environment.




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6.  IANA Considerations

   This draft is requirements, and does not request anything of IANA.

7.  Acknowledgement

   The authors would like to thank Wes George, Ahmed Abro, Qin Wu, Eric
   Yu, Joel Halpern, Scott Brim, Nancy Cam-Winget, DaCheng Zhang, Alia
   Atlas, and Jeff Haas for their contributions to the I2RS security
   requirements discussion and this document.  The authors would like to
   thank Bob Moskowitz, Kathleen Moriarty, Stephen Farrell, Radia
   Perlman, Alvaro Retana, Ben Campbell, and Alissa Cooper for their
   review of these requirements.

8.  References

8.1.  Normative References

   [I-D.ietf-i2rs-security-environment-reqs]
              Migault, D., Halpern, J., and S. Hares, "I2RS Environment
              Security Requirements", draft-ietf-i2rs-security-
              environment-reqs-01 (work in progress), April 2016.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC4107]  Bellovin, S. and R. Housley, "Guidelines for Cryptographic
              Key Management", BCP 107, RFC 4107, DOI 10.17487/RFC4107,
              June 2005, <http://www.rfc-editor.org/info/rfc4107>.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
              FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
              <http://www.rfc-editor.org/info/rfc4949>.

   [RFC7258]  Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
              Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
              2014, <http://www.rfc-editor.org/info/rfc7258>.

   [RFC7921]  Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", RFC 7921, DOI 10.17487/RFC7921, June 2016,
              <http://www.rfc-editor.org/info/rfc7921>.







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   [RFC7922]  Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to
              the Routing System (I2RS) Traceability: Framework and
              Information Model", RFC 7922, DOI 10.17487/RFC7922, June
              2016, <http://www.rfc-editor.org/info/rfc7922>.

   [RFC7923]  Voit, E., Clemm, A., and A. Gonzalez Prieto, "Requirements
              for Subscription to YANG Datastores", RFC 7923,
              DOI 10.17487/RFC7923, June 2016,
              <http://www.rfc-editor.org/info/rfc7923>.

8.2.  Informative References

   [I-D.ietf-i2rs-ephemeral-state]
              Haas, J. and S. Hares, "I2RS Ephemeral State
              Requirements", draft-ietf-i2rs-ephemeral-state-18 (work in
              progress), September 2016.

   [I-D.ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ietf-netconf-restconf-17 (work in
              progress), September 2016.

   [I-D.ietf-taps-transports]
              Fairhurst, G., Trammell, B., and M. Kuehlewind, "Services
              provided by IETF transport protocols and congestion
              control mechanisms", draft-ietf-taps-transports-11 (work
              in progress), July 2016.

   [RFC2865]  Rigney, C., Willens, S., Rubens, A., and W. Simpson,
              "Remote Authentication Dial In User Service (RADIUS)",
              RFC 2865, DOI 10.17487/RFC2865, June 2000,
              <http://www.rfc-editor.org/info/rfc2865>.

   [RFC4960]  Stewart, R., Ed., "Stream Control Transmission Protocol",
              RFC 4960, DOI 10.17487/RFC4960, September 2007,
              <http://www.rfc-editor.org/info/rfc4960>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <http://www.rfc-editor.org/info/rfc5246>.

   [RFC5764]  McGrew, D. and E. Rescorla, "Datagram Transport Layer
              Security (DTLS) Extension to Establish Keys for the Secure
              Real-time Transport Protocol (SRTP)", RFC 5764,
              DOI 10.17487/RFC5764, May 2010,
              <http://www.rfc-editor.org/info/rfc5764>.




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   [RFC6238]  M'Raihi, D., Machani, S., Pei, M., and J. Rydell, "TOTP:
              Time-Based One-Time Password Algorithm", RFC 6238,
              DOI 10.17487/RFC6238, May 2011,
              <http://www.rfc-editor.org/info/rfc6238>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <http://www.rfc-editor.org/info/rfc6241>.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
              January 2012, <http://www.rfc-editor.org/info/rfc6347>.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <http://www.rfc-editor.org/info/rfc6536>.

   [RFC6614]  Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
              "Transport Layer Security (TLS) Encryption for RADIUS",
              RFC 6614, DOI 10.17487/RFC6614, May 2012,
              <http://www.rfc-editor.org/info/rfc6614>.

   [RFC6733]  Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
              Ed., "Diameter Base Protocol", RFC 6733,
              DOI 10.17487/RFC6733, October 2012,
              <http://www.rfc-editor.org/info/rfc6733>.

   [RFC7920]  Atlas, A., Ed., Nadeau, T., Ed., and D. Ward, "Problem
              Statement for the Interface to the Routing System",
              RFC 7920, DOI 10.17487/RFC7920, June 2016,
              <http://www.rfc-editor.org/info/rfc7920>.

Authors' Addresses

   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI  48176
   USA

   Email: shares@ndzh.com








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   Daniel Migault
   Ericsson
   8400 boulevard Decarie
   Montreal, QC  HAP 2N2
   Canada

   Email: daniel.migault@ericsson.com


   Joel Halpern
   Ericsson
   US

   Email: joel.halpern@ericsson.com





































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