I2RS working group                                              S. Hares
Internet-Draft                                                    Huawei
Intended status: Standards Track                           June 24, 2015
Expires: December 26, 2015

                   I2RS Security Related Requirements


   This presents an security-related requirements for the I2RS protocol
   for mutual authentication, transport protocols, data transfer and

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on December 26, 2015.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  10 I2RS General Requirements  . . . . . . . . . . . . . .   3
     1.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Security-Related Requirements . . . . . . . . . . . . . . . .   5
     2.1.  Mutual authentication of I2RS client and I2RS Agent . . .   5
     2.2.  Transport Requirements Based on Mutual Authentication . .   6
     2.3.  Data Confidentiality Requirements . . . . . . . . . . . .   6
     2.4.  Message Integrity Requirements  . . . . . . . . . . . . .   7
       2.4.1.  Handling Multiple Messages  . . . . . . . . . . . . .   7
     2.5.  Role-Based Data Model Security  . . . . . . . . . . . . .   7
   3.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   8
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The Interface to the Routing System (I2RS) provides read and write
   access to the information and state within the routing process.  The
   I2RS client interacts with one or more I2RS agents to collect
   information from network routing systems.

   This document describes the requirements for the I2RS protocol in the
   security-related areas of mutual authentication of the I2RS client
   and agent, the transport protocol carrying the I2RS protocol
   messages, and the atomicity of the transactions.  These requirements
   were initially described in the [I-D.ietf-i2rs-architecture]
   document.  These security requirements are also part of the list of
   top ten requirements for the I2RS protocol indicated in the section

   [I-D.haas-i2rs-ephemeral-state-reqs] discusses of I2RS roles-based
   write conflict resolution in the ephemeral data store using the I2RS
   Client Identity, I2RS Secondary Identity and priority.  The draft
   [I-D.ietf-i2rs-traceability] describes the traceability framework and
   its requirements for I2RS.  The draft
   [I-D.ietf-i2rs-pub-sub-requirements] describe the requirements for
   I2RS to be able to publish information or have a remote client
   subscribe to an information data stream.

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1.1.  10 I2RS General Requirements

   1.   The I2RS protocol SHOULD support highly reliable notifications
        (but not perfectly reliable notifications) from an I2RS agent to
        an I2RS client.

   2.   The I2RS protocol SHOULD support a high bandwidth, asynchronous
        interface, with real-time guarantees on getting data from an
        I2RS agent by an I2RS client.

   3.   The I2RS protocol will operate on data models which may be
        protocol independent or protocol dependent.

   4.   I2RS Agent needs to record the client identity when a node is
        created or modified.  The I2RS Agent needs to be able to read
        the client identity of a node and use the client identity's
        associated priority to resolve conflicts.  The secondary
        identity is useful for traceability and may also be recorded.

   5.   Client identity will have only one priority for the client
        identity.  A collision on writes is considered an error, but
        priority is utilized to compare requests from two different
        clients in order to modify an existing node entry.  Only an
        entry from a client which is higher priority can modify an
        existing entry (First entry wins).  Priority only has meaning at
        the time of use.

   6.   The Agent identity and the Client identity should be passed
        outside of the I2RS protocol in a authentication and
        authorization protocol (AAA).  Client priority may be passed in
        the AAA protocol.  The values of identities are originally set
        by operators, and not standardized.

   7.   An I2RS Client and I2RS Agent mutually authenticate each other
        based on pre-established authenticated identities.

   8.   Secondary identity data is read-only meta-data that is recorded
        by the I2RS agent which associated with a data model's node when
        the node is written, updated or deleted.  Just like the primary
        identity, the secondary identity is only recorded when the data
        node is written or updated or deleted.

   9.   I2RS agent can have a lower priority I2RS client attempting to
        modify a higher priority client's entry in a data model.  The
        filtering out of lower priority clients attempting to write or
        modify a higher priority client's entry in a data model SHOULD
        be effectively handled and not put an undue strain on the I2RS
        agent.  Note: Jeff's suggests that priority is kept at the NACM

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        at the client level (rather than the path level or the group
        level) will allow these lower priority clients to be filtered
        out using an extended NACM approach.  This is only a suggestion
        of a method to provide the requirement

   10.  The I2RS protocol MUST support the use of a secure transport.
        However, certain functions such as notifications MAY use a non-
        secure transport.  Each model or service (notification, logging)
        must define within the model or service the valid uses of a non-
        secure transport.

1.2.  Definitions

   This document utilizes the definitions found in the following drafts:
   [RFC4949], and [I-D.ietf-i2rs-architecture]

   Specifically, this document utilizes the following definitions:


      [RFC4949] describes authentication as the process of verifying
      (i.e., establishing the truth of) an attribute value claimed by or
      for a system entity or system resource.  Authentication has two
      steps: identify and verify.

   Data Confidentiality

      [RFC4949] describes data confidentiality as having two properties:
      a) data is not disclosed to system entities unless they have been
      authorized to know, and b) data is not disclosed to unauthorized
      individuals, entities or processes.  The key point is that
      confidentiality implies that the originator has the ability to
      authorize where the information goes.  Confidentiality is
      important for both read and write scope of the data.

   Data Privacy

      [RFC4949] describes data privacy as a synonym for data
      confidentiality.  This I2RS document will utilize data privacy as
      a synonym for data confidentiality.

   Mutual Authentication

      [RFC4949] implies that mutual authentication exists between two
      interacting system entities.  Mutual authentication in I2RS
      implies that both sides move from a state of mutual suspicion to
      mutually authenticated communication afte each system has been
      identified and validated by its peer system.

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   Security audit trail

      [RFC4949] (page 254) describes a security audit trail as a
      chronological record of system activities that is sufficient to
      enable the reconstruction and examination of the sequence
      environments and activities surrounding or leading to an
      operation, procedure, or event in a security-relevant transaction
      from inception to final results.  Requirements to support a
      security audit is not covered in this document.  The draft
      [I-D.ietf-i2rs-traceability] describes traceability for I2RS
      interface and protocol.  Traceability is not equivalent to a
      security audit trail.

   I2RS integrity

      The data transfer as it is transmitted between client and agent
      cannot be modified by unauthorized parties without detection.

2.  Security-Related Requirements

   The security for the I2RS protocol requires mutually authenticated
   I2RS client and I2RS agent.  The I2RS client and I2RS agent using the
   I2RS protocol MUST be able to exchange data over a secure transport,
   but some functions may operate on non-secure transport.  The I2RS
   protocol MUST BE able to provide atomicity of a transaction, but it
   is not required to multi-message atomicity and rollback mechanisms
   transactions.  Multiple messages transactions may be impacted by the
   interdependency of data.  This section discusses these details of
   these securitry requirements.

2.1.  Mutual authentication of I2RS client and I2RS Agent

   The I2RS architecture [I-D.ietf-i2rs-architecture] sets the following

   o  All I2RS clients and I2RS agents MUST have at least one unique
      identifier that uniquely identifies each party.

   o  The I2RS protocol MUST utilize these identifiers for mutual
      identification of the I2RS client and I2RS agent.

   o  An I2RS agent, upon receiving an I2RS message from a client, MUST
      confirm that the client has a valid identity.

   o  The client, upon receiving an I2RS message from an agent, MUST
      confirm the I2RS identity.

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   o  Identity distribution and the loading of these identities into
      I2RS agent and I2RS Client occur outside the I2RS protocol.

   o  The I2RS protocol SHOULD assume some mechanism (IETF or private)
      will distribute or load identities so that the I2RS client/agent
      has these identities prior to the I2RS protocol establishing a
      connection between I2RS client and I2RS agent.

   o  Each Identity will be linked to one priority

   o  Each Identity is associated with one secondary identity during a
      particular read/write sequence, but the secondary identity may
      vary during the time a connection between the I2RS client and I2RS
      agent is active.  The variance of the secondary identity allows
      the I2rs client to be associated with multiple applications and
      pass along an identifier for these applications in the secondary

2.2.  Transport Requirements Based on Mutual Authentication

   The data security of the I2RS protocol MUST be able to support
   transfer of the data over a secure transport and optionally be able
   to support a non-security transport.  A security transport is defined
   to have the qualities of confidentiality, has message integrity, and
   supports end-to-end integrity of the I2RS client-agent session.

   A secure transport also must be 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.
   Pre-shared keys is considered for this document to be a key
   management system.  In addition, the key management mechanisms need
   to be able to update the keys before they have lost sufficient
   security strengths, without breaking the connection between the
   agents and clients.

   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 connect MAY elect to use a single secure transport session or
   a single non-secure transport session.

2.3.  Data Confidentiality Requirements

   In a critical infrastructure, certain data within routing elements is
   sensitive and read/write operations on such data must be controlled
   in order to protect its confidentiality.  For example, most carriers
   do not want a router's configuration and data flow statistics known
   by hackers or their competitors.  While carriers may share peering

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   information, most carriers do not share configuration and traffic
   statistics.  To achieve this, access control to sensitive data needs
   to be provided for this data, and the confidentiality protection on
   such data during transportation needs to be enforced.

2.4.  Message Integrity Requirements

   An integrity protection mechanism for I2RS should be able to ensure
   the following: 1) the data being protected are not modified without
   detection during its transportation and 2) the data is actually from
   where it is expected to come from 3) the data is not repeated from
   some earlier interaction of the protocol.  That is, when both
   confidentiality and integrity of data is properly protected, it is
   possible to ensure that encrypted data are not modified or replayed
   without detection.

2.4.1.  Handling Multiple Messages

   Section 7.9 of the [I-D.ietf-i2rs-architecture] states the I2RS
   architecture does not include multi-message atomicity and rollback
   mechanisms, but suggests an I2RS client may inidicate one of the
   following error handling techniques for a given message sent to the
   I2RS client:

   1.  Perform all or none: All operations succeed or none of them will
       be applied.  This useful when there are mutual dependencies.

   2.  Perform until error: Operations are applied in order, and when
       error occurs the processing stops.  This is useful when
       dependencies exist between multiple-message operations, and order
       is important.

   3.  Perform all storing errors: Perform all actions storing error
       indications for errors.  This method can be used when there are
       no dependencies between operations, and the client wants to sort
       it out.

2.5.  Role-Based Data Model Security

   The [I-D.ietf-i2rs-architecture] defines a role or security role as
   specifying read, write, or notification access within a data model
   that a client has to an agent's data model.

   The rules around what role is permitted to access and manipulate what
   information plus a secure transport (which protects the data in
   transit) SHOULD ensure that data of any level of sensitivity is
   reasonably protected from being observed by those without permission
   to view it so that privacy requirements are met.  Observer without

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   permission can refer to other I2RS clients, attackers, or assorted
   MITM (man-in-the-middle) monkeys.

   Role security MUST work when multiple transport connections are being
   used between the I2RS client and I2RS agent as the I2RS architecture
   [I-D.ietf-i2rs-architecture] states.  These transport message streams
   may start/stop without affecting the existence of the client/agent
   data exchange.  TCP supports a single stream of data.  SCTP [RFC4960]
   provides security for multiple streams plus end-to-end transport of

   I2RS clients MAY be used by multiple applications to configure
   routing via I2RS agents, receive status reports, turn on the I2RS
   audit stream, or turn on I2RS traceability.  An application software
   using I2RS client functions can host several multiple secure
   identities, but each connection will use only one identity with one
   priority.  Therefore, the security of each I2RS Client to I2RS Agent
   connection is unique.

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

3.  Acknowledgement

   The author 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 I2RS security
   requirement discussion and this document.

4.  IANA Considerations

   This draft includes no request to IANA.

5.  Security Considerations

   This is a document about security requirements for the I2RS protocol
   and data modules.  The whole document is security considerations.

6.  References

6.1.  Normative References

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

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6.2.  Informative References

              Haas, J., "I2RS Ephemeral State Requirements", draft-haas-
              i2rs-ephemeral-state-reqs-00 (work in progress), May 2015.

              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-09 (work in
              progress), March 2015.

              Atlas, A., Nadeau, T., and D. Ward, "Interface to the
              Routing System Problem Statement", draft-ietf-i2rs-
              problem-statement-06 (work in progress), January 2015.

              Voit, E., Clemm, A., and A. Prieto, "Requirements for
              Subscription to YANG Datastores", draft-ietf-i2rs-pub-sub-
              requirements-02 (work in progress), March 2015.

              Bahadur, N., Folkes, R., Kini, S., and J. Medved, "Routing
              Information Base Info Model", draft-ietf-i2rs-rib-info-
              model-06 (work in progress), March 2015.

              Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to
              the Routing System (I2RS) Traceability: Framework and
              Information Model", draft-ietf-i2rs-traceability-03 (work
              in progress), May 2015.

   [RFC4785]  Blumenthal, U. and P. Goel, "Pre-Shared Key (PSK)
              Ciphersuites with NULL Encryption for Transport Layer
              Security (TLS)", RFC 4785, January 2007.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2", RFC
              4949, August 2007.

   [RFC4960]  Stewart, R., "Stream Control Transmission Protocol", RFC
              4960, September 2007.

Author's Address

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   Susan Hares
   7453 Hickory Hill
   Saline, MI  48176

   Email: shares@ndzh.com

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