Security Policy Translation in Interface to Network Security Functions
draft-yang-i2nsf-security-policy-translation-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
|
|
|---|---|---|---|
| Authors | Jinhyuk Yang , Jaehoon Paul Jeong , Jinyong Tim Kim | ||
| Last updated | 2018-07-17 | ||
| RFC stream | (None) | ||
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| Additional resources | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
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| IESG | IESG state | I-D Exists | |
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| Send notices to | (None) |
draft-yang-i2nsf-security-policy-translation-01
I2NSF Working Group J. Yang
Internet-Draft J. Jeong
Intended status: Informational J. Kim
Expires: January 18, 2019 Sungkyunkwan University
July 17, 2018
Security Policy Translation in Interface to Network Security Functions
draft-yang-i2nsf-security-policy-translation-01
Abstract
This document proposes a scheme of security policy translation (i.e.,
Security Policy Translator) in Interface to Network Security
Functions (I2NSF) Framework. When I2NSF User delivers a high-level
security policy for a security service, Security Policy Translator in
Security Controller translates it into a low-level security policy
for Network Security Functions (NSFs).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 18, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Necessity for Policy Translator . . . . . . . . . . . . . . . 2
4. Design of Policy Translator . . . . . . . . . . . . . . . . . 3
4.1. Overall Structure of Policy Translator . . . . . . . . . 3
4.2. DFA-based Data Extractor . . . . . . . . . . . . . . . . 6
4.3. Data Converter . . . . . . . . . . . . . . . . . . . . . 6
4.4. Context-free Grammar-based Policy Generator . . . . . . . 7
5. Features of Policy Translator Design . . . . . . . . . . . . 7
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
7. Informative References . . . . . . . . . . . . . . . . . . . 8
Appendix A. Changes from draft-yang-i2nsf-security-policy-
translation-00 . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
This document defines a scheme of a security policy translation in
Interface to Network Security Functions (I2NSF) Framework [RFC8329].
First of all, this document explains the necessity of a security
policy translator (shortly called policy translator) in the I2NSF
framework.
The policy translator resides in Security Controller in the I2NSF
framework and translates a high-level security policy to a low-level
security policy for Network Security Functions (NSFs). A high-level
policy is specified by I2NSF User in the I2NSF framework and is
delivered to Security Controller via Consumer-Facing Interface
[consumer-facing-inf-dm]. A low-level policy is translated by Policy
Translator in Security Controller and is delivered to NSFs to execute
the rules corresponding to the low-level policy via NSF-Facing
Interface [nsf-facing-inf-dm].
2. Terminology
This document uses the terminology specified in [i2nsf-terminology]
[RFC8329].
3. Necessity for Policy Translator
Security Controller acts as a coordinator between I2NSF User and
NSFs. Also, Security Controller has capability information of NSFs
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that are registered via Registration Interface [registration-inf-dm]
by Developer's Management System [RFC8329].
As a coordinator, Security Controller needs to generate a low-level
policy in the form of security rules intended by the high-level
policy, which can be understood by the corresponding NSFs.
A high-level security policy is specified by RESTCONF/YANG
[RFC8040][RFC6020], and a low-level security policy is specified by
NETCONF/YANG [RFC6241][RFC6020]. The translation from a high-level
security policy to the corresponding low-level security policy will
be able to rapidly elevate I2NSF in real-world deployment. A rule in
a high-level policy can include a broad target object, such as
employees in a company for a security service (e.g., firewall and web
filter). Such employees are from human resource (HR) department,
software engineering department, and advertisement department. A
keyword of employee needs to be mapped to these employees from
various departments. This mapping needs to be handled by a policy
translator in a flexible way while understanding the intention of a
policy specification.
This document proposes an approach using Automata theory for the
policy tranlation, such as deterministic finite automaton (DFA) and
context-free grammar. Note that Automata theory is the foundation of
programming languates and compilers. Thus, with this approach, I2NSF
User can easily specify a high-level security policy that will be
enforced into the corresponding NSFs with a compatible low-level
security policy with the help of Policy Translator. Also, for easy
managment of Policy Translator, a modularized translator structure is
proposed.
4. Design of Policy Translator
Commonly used security policies are created as xml files. A popular
way to change the format of an xml file is to use an xslt document.
However, the use of xslt makes it difficult to manage the policy
translator and to handle the registration of new capabilities of
NSFs. With the nessity for policy translator, this document a policy
translator based on Automata theory.
4.1. Overall Structure of Policy Translator
Figure 1 shows the overall design for Policy Translator in Security
Controller. There are three main parts for Policy Translator:
Extractor, Capability Converter, and Policy Generator.
Extractor is a DFA-based tool for extracting data from a high-level
policy which I2NSF User delivered via Consumer-Facing Interface.
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Data Converter converts the extracted data to the capabilities of
target NSFs for a low-level policy. It refers to NSF Database (DB)
in order to convert an abstract subject or object into the
corresponding concrete subject or object (e.g., IP address and
website URL). Policy Generator generates a low-level policy which
will execute the NSF capabilities from Converter.
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+------------+
| I2NSF User |
+-----+------+
Security | Consumer-Facing Interface
Controller V
+------------------------+-------------------------+
| High-Level |
| Policy |
| (from I2NSF User) |
| Policy | |
| Translator V |
| +---------------------+----------------------+ |
| | | | |
| | +-------+--------+ | |
| | | DFA-based | | |
| | | Data Extractor | | |
| | +-------+--------+ | |
| | | Extracted Data from | |
| | V High-Level Policy | |
| | +-----+-----+ | |
| | | Data | <-> Refer to | |
| | | Converter | NSF DB | |
| | +-----+-----+ | |
| | | Required Data for | |
| | V Target NSFs | |
| | +-------+-------+ | |
| | | Context-free | | |
| | | Grammar-based | | |
| | | Policy | | |
| | | Generator | | |
| | +-------+-------+ | |
| | | | |
| +---------------------+----------------------+ |
| | |
| Low-Level Policy |
| (for NSFs) |
| | |
+------------------------+-------------------------+
|
V NSF-Facing Interface
Figure 1: The Overall Design of Policy Translator
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4.2. DFA-based Data Extractor
Figure 2 shows a design for Data Extractor in the policy translator.
If the high-level policy contains data along the hierarchical
structure of the standard YANG data model, data can be easily
extracted using the state transition machine, DFA.
The extracted data is processed and used by an NSF to understand it.
Extractor can be constructed by designing a DFA with the same
hierarchical structure as a YANG data model.
Since the translator is modularized into a DFA structure, a visual
understanding is feasible. Also, the following structure of
Extractor is easy to manage. If I2NSF User wants to modify the data
model of a high-level policy, it only needs to change the connection
of the relevant DFA node.
<tag 1> <tag 2>
+----------+ ------> +----------+ -------> +-------------+
| accepter | | | . . . | extractor 1 |
+----------+ <------ | | <------- +-------------+
</tag 1> | | </tag 2>
| |
| | <tag 3>
| | -------> +-------------+
| | . . . | extractor 2 |
| | <------- +-------------+
| middle 1 | </tag 3>
| | .
| | .
| | .
| | <tag M>
| | -------> +-------------+
| | . . . | extractor N |
| | <------- +-------------+
| | </tag M>
+----------+
Figure 2: The Design of Data Extractor
4.3. Data Converter
Every NSF has its own unique capabilities. The capabilities of an
NSF are registered into Security Controller by a Developer's
Management System, which manages the NSF, via Registration Interface.
Therefore, Security Controller already has all information about the
capabilities of NSFs. This means that Security Controller can find
target NSFs with only the data (e.g., subject and object for a
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security policy) of the high-level policy by comparing all
capabilities of each NSF. This search process for appropriate NSFs
is called by NSF provisioning, and it eliminates the need for I2NSF
User to specify the target NSFs explicitly. Data Converter selects
target NSFs and converts the extracted data into the capabilities of
selected NSFs. If Security Controller uses this data convertor, it
can provide the NSF provisioning function to the I2NSF User
automatically. Thus, the translator design provides big benefits to
I2NSF Framework.
4.4. Context-free Grammar-based Policy Generator
The productions that makes up the low-level security policy are
categorized into two types, Structure Production and Content
Production. Structure Production is for grouping other tags into a
hierarchy. A security manager constructs Structure Production in the
form of an expression as the following equation:
o [structure_prod] ->
<structure_tag>[policy:1][policy:2]...[policy:n]</structure_tag>
Content Production is for injecting data into low-level policies to
be generated. The manager can construct Content Production in the
form of an expression as following equation:
o [content_prod] -> <content_tag>[content_data]</content_tag>
o [content_data] -> data:1 | data:2 | ... | data:n
o [content_prod] -> [content_prod][content_prod] (Where duplication
is allowed.)
5. Features of Policy Translator Design
First, by showing the visualized translator structure, the manager
can handle various policy changes. Translator can be shown by
visualizing DFA and Context-free Grammar so that the manager can
easily understand the structure of Policy Translator.
Second, if I2NSF User only keeps the hierarchy of the data model,
I2NSF User can freely create high-level policies. In the case of
DFA, data extraction can be performed in the same way even if the
order of input is changed. The design of the policy translator is
more flexible than the existing method that works by keeping the tag
's position and order exactly.
Third, the structure of Policy Translator can be updated even while
Policy Translator is operating. Because Policy Translator is
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modularized, the translator can adapt to changes in the NSF
capability while the I2NSF framework is running. The function of
changing the translator's structure can be provided through
Registration Interface.
6. Acknowledgments
This work was supported by Institute for Information & communications
Technology Promotion (IITP) grant funded by the Korea MSIT (Ministry
of Science and ICT) (R-20160222-002755, Cloud based Security
Intelligence Technology Development for the Customized Security
Service Provisioning).
This work was supported in part by the MSIT under the ITRC
(Information Technology Research Center) support program (IITP-
2018-2017-0-01633) supervised by the IITP.
7. Informative References
[consumer-facing-inf-dm]
Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares,
"I2NSF Consumer-Facing Interface YANG Data Model", draft-
ietf-i2nsf-consumer-facing-interface-dm-01 (work in
progress), July 2018.
[i2nsf-terminology]
Hares, S., Strassner, J., Lopez, D., Xia, L., and H.
Birkholz, "Interface to Network Security Functions (I2NSF)
Terminology", draft-ietf-i2nsf-terminology-06 (work in
progress), July 2018.
[nsf-facing-inf-dm]
Kim, J., Jeong, J., Park, J., Hares, S., and Q. Lin,
"I2NSF Network Security Function-Facing Interface YANG
Data Model", draft-ietf-i2nsf-nsf-facing-interface-data-
model-01 (work in progress), July 2018.
[registration-inf-dm]
Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF
Registration Interface YANG Data Model", draft-hyun-i2nsf-
registration-dm-05 (work in progress), July 2018.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
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[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, January 2017.
[RFC8329] Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R.
Kumar, "Framework for Interface to Network Security
Functions", RFC 8329, February 2018.
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Appendix A. Changes from draft-yang-i2nsf-security-policy-
translation-00
The following changes are made from draft-yang-i2nsf-security-policy-
translation-00:
o In Section 3, the necessity for the proposed translation design is
clarified.
o In Section 4.3, the description of Data Converter is clarified.
o In Section 4.4, "Structure Grammar" and "Content Grammar" are
replaced with "Structure Production" and "Content Production",
respectively.
o The references are updated to reflect the latest documents.
Authors' Addresses
Jinhyuk Yang
Department of Computer Engineering
Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu
Suwon, Gyeonggi-Do 16419
Republic of Korea
Phone: +82 10 8520 8039
EMail: jin.hyuk@skku.edu
Jaehoon Paul Jeong
Department of Software
Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu
Suwon, Gyeonggi-Do 16419
Republic of Korea
Phone: +82 31 299 4957
Fax: +82 31 290 7996
EMail: pauljeong@skku.edu
URI: http://iotlab.skku.edu/people-jaehoon-jeong.php
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Jinyong Tim Kim
Department of Computer Engineering
Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu
Suwon, Gyeonggi-Do 16419
Republic of Korea
Phone: +82 10 8273 0930
EMail: timkim@skku.edu
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