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Versions: (draft-hansen-media-type-suffix-regs) 00 01 02 03 04 05 06 07 08 RFC 6839

Network Working Group                                          T. Hansen
Internet-Draft                                         AT&T Laboratories
Updates: 3023 (if approved)                                July 17, 2012
Intended status: Best Current Practice
Expires: January 16, 2013


            Additional Media Type Structured Syntax Suffixes
              draft-ietf-appsawg-media-type-suffix-regs-02

Abstract

   A content media type name sometimes includes partitioned meta-
   information distinguish by a Structured Syntax, to permit noting an
   attribute of the media as a suffix to the name.  This document
   defines several Structured Syntax Suffixes for use with media type
   registrations.  In particular, it defines and registers the "+json",
   "+ber", "+der", "+fastinfoset", "+wbxml" and "+zip" Structured Syntax
   Suffixes, and updates the "+xml" Message Type Structured Syntax
   Suffix registration.

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 January 16, 2013.

Copyright Notice

   Copyright (c) 2012 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


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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  When to Use these Structured Syntax Suffixes . . . . . . . . .  2
   3.  Initial Structured Syntax Suffix Definitions . . . . . . . . .  3
     3.1.  The +json Structured Syntax Suffix . . . . . . . . . . . .  3
     3.2.  The +ber Structured Syntax Suffixes  . . . . . . . . . . .  4
     3.3.  The +der Structured Syntax Suffixes  . . . . . . . . . . .  5
     3.4.  The +fastinfoset Structured Syntax Suffix  . . . . . . . .  6
     3.5.  The +wbxml Structured Syntax Suffix  . . . . . . . . . . .  7
     3.6.  The +zip Structured Syntax Suffix  . . . . . . . . . . . .  8
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 10
   Appendix A. Change History . . . . . . . . . . . . . . . . . . . . 11
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.  Introduction

   [RFC3023] created the +xml suffix convention that can be used when
   defining names for media types whose representation uses XML
   underneath.  That is, they could have been successfully parsed as if
   the media type had been application/xml in addition to their being
   parsed as their media type that is using the +xml suffix.  [I-D.ietf-
   appsawg-media-type-regs] defines the Message Type Structured Syntax
   Suffixes registry to be used for such Structured Syntax Suffixes.

   A variety of Structured Syntax Suffixes have already been used in
   some media type registrations, in particular "+json", "+der",
   "+fastinfoset" and "+wbxml".  This document defines and registers
   these Structured Syntax Suffixes in the Structured Syntax Suffix
   registry, along with "+ber" and "+zip".  In addition, this document
   updates the "+xml" Structured Syntax Suffix registration.

   Discussion of this document should occur in the Apps Area Working
   Group (apps-discuss@ietf.org).  [RFC Editor note: remove this
   paragraph.]

   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 [RFC2119].

2.  When to Use these Structured Syntax Suffixes

   Each of the Structured Syntax Suffixes defined in this document is
   appropriate for use when the media type identifies the semantics of
   the protocol payload.  That is, knowing the semantics of the specific
   media type provides for more specific processing of the content than
   that afforded by generic processing of the underlying representation.


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   At the same time, using the suffix allows receivers of the media
   types to do generic processing of the underlying representation in
   cases where

      they do not need to perform special handling of the particular
      semantics of the exact media type, and,

      there is no special knowledge needed by such a generic processor
      in order to parse that underlying representation other than what
      would be needed to parse any example of that underlying
      representation.

3.  Initial Structured Syntax Suffix Definitions

3.1.  The +json Structured Syntax Suffix

   [RFC4627] defines the "application/json" media type.  The suffix
   "+json" MAY be used with any media type whose representation follows
   that established for "application/json".  The Message Type Structured
   Syntax Suffix registration form follows.  See [I-D.ietf-appsawg-
   media-type-regs] for definitions of each of the registration form
   headings.

   Name:               JavaScript Object Notation (JSON)

   +suffix:            +json

   References:         [RFC4627]

   Encoding considerations: Per [RFC4627], JSON is allowed to be
                       represented using UTF-8, UTF-16, or UTF-32.  When
                       JSON is written in UTF-8, JSON is 8bit compatible
                       ([RFC2045]).  When JSON is written in UTF-16 or
                       UTF-32, JSON is binary ([RFC2045]).

   Fragment identifier considerations:

                          The syntax and semantics of fragment
                          identifiers specified for +json SHOULD be as
                          specified for "application/json".  (At
                          publication of this document, there is no
                          fragment identification syntax defined for
                          "application/json".)

                          The syntax and semantics for fragment
                          identifiers for a specific "xxx/yyy+json"
                          SHOULD be processed as follows:

                             For cases defined in +json, where the





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                             fragment identifier resolves per the +json
                             rules, then as specified in +json.

                             For cases defined in +json, where the
                             fragment identifier does not resolve per
                             the +json rules, then as specified in "xxx/
                             yyy+json".

                             For cases not defined in +json, then as
                             specified in "xxx/yyy+json".

   Interoperability considerations: n/a

   Security considerations: See [RFC4627]

   Contact:            Apps Area Working Group (apps-discuss@ietf.org)

   Author/Change controller: The Apps Area Working Group has change
                       control over this registration.

3.2.  The +ber Structured Syntax Suffixes

   The ITU defined the Basic Encoding Rules (BER) message transfer
   syntax in [ITU.X690.2008].  The suffix "+ber" MAY be used with any
   media type whose representation follows the BER message transfer
   syntax.  The Message Type Structured Syntax Suffix registration form
   for +ber follows:

   Name:               Basic Encoding Rules (BER) message transfer
                       syntax

   +suffix:            +ber

   References:         [ITU.X690.2008]

   Encoding considerations: BER is a binary encoding.

   Fragment identifier considerations: n/a

   Interoperability considerations: n/a

   Security considerations: Each individual media type registered with a
                       +ber suffix can have additional security
                       considerations.

                       BER has a type-length-value structure, and it is
                       easy to construct malicious content with invalid
                       length fields that can cause buffer overrun
                       conditions.

                       Some BER schema allow for arbitrary levels of
                       nesting, which may make it possible to construct
                       malicious content that will cause a stack
                       overflow.

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                       Interpreters of the BER structures should be
                       aware of these issues and should take appropriate
                       measures to guard against buffer overflows and
                       stack overruns in particular and malicious
                       content in general.

   Contact:            Apps Area Working Group (apps-discuss@ietf.org)

   Author/Change controller: The Apps Area Working Group has change
                       control over this registration.

3.3.  The +der Structured Syntax Suffixes

   The ITU defined the Distinguished Encoding Rules (DER) message
   transfer syntax in [ITU.X690.2008].  The suffix "+der" MAY be used
   with any media type whose representation follows the DER message
   transfer syntax.  The Message Type Structured Syntax Suffix
   registration form for +der follows:

   Name:               Distinguished Encoding Rules (DER) message
                       transfer syntax

   +suffix:            +der

   References:         [ITU.X690.2008]

   Encoding considerations: DER is a binary encoding.

   Fragment identifier considerations: n/a

   Interoperability considerations: n/a

   Security considerations: Each individual media type registered with a
                       +ber suffix can have additional security
                       considerations.

                       DER has a type-length-value structure, and it is
                       easy to construct malicious content with invalid
                       length fields that can cause buffer overrun
                       conditions.

                       Some DER schema allow for arbitrary levels of
                       nesting, which may make it possible to construct
                       malicious content that will cause a stack
                       overflow.

                       Interpreters of the DER structures should be







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                       aware of these issues and should take appropriate
                       measures to guard against buffer overflows and
                       stack overruns in particular and malicious
                       content in general.

   Contact:            Apps Area Working Group (apps-discuss@ietf.org)

   Author/Change controller: The Apps Area Working Group has change
                       control over this registration.

3.4.  The +fastinfoset Structured Syntax Suffix

   The ITU defined the Fast Infoset document format as a binary
   representation of the XML Information Set in [ITU.X891.2005].  These
   documents further define the "application/fastinfoset" media type.
   The suffix "+fastinfoset" MAY be used with any media type whose
   representation follows that established for "application/
   fastinfoset".  The Message Type Structured Syntax Suffix registration
   form follows:

   Name:               Fast Infoset document format

   +suffix:            +fastinfoset

   References:         [ITU.X891.2005]

   Encoding considerations: Fast Infoset is a binary encoding.  The
                       binary, quoted-printable and base64 content-
                       transfer-encodings are suitable for use with Fast
                       Infoset.

   Fragment identifier considerations:

                          The syntax and semantics of fragment
                          identifiers specified for +fastinfoset SHOULD
                          be as specified for "application/fastinfoset".
                          (At publication of this document, there is no
                          fragment identification syntax defined for
                          "application/fastinfoset".)

                          The syntax and semantics for fragment
                          identifiers for a specific "xxx/
                          yyy+fastinfoset" SHOULD be processed as
                          follows:

                             For cases defined in +fastinfoset, where
                             the fragment identifier resolves per the
                             +fastinfoset rules, then as specified in
                             +fastinfoset.

                             For cases defined in +fastinfoset, where
                             the fragment identifier does not resolve



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                             per the +fastinfoset rules, then as
                             specified in "xxx/yyy+fastinfoset".

                             For cases not defined in +fastinfoset, then
                             as specified in "xxx/yyy+fastinfoset".

   Interoperability considerations: n/a

   Security considerations: There are no security considerations
                       inherent in Fast Infoset.  Each individual media
                       type registered with a +fastinfoset suffix can
                       have additional security considerations.

   Contact:            Apps Area Working Group (apps-discuss@ietf.org)

   Author/Change controller: The Apps Area Working Group has change
                       control over this registration.

3.5.  The +wbxml Structured Syntax Suffix

   The WAP Forum has defined the WAP Binary XML (WBXML) document format
   as a binary representation of XML in [WBXML].  This document further
   defines the "application/vnd.wap.wbxml" media type.  The suffix
   "+wbxml" MAY be used with any media type whose representation follows
   that established for "application/vnd.wap.wbxml".  The Message Type
   Structured Syntax Suffix registration form follows:

   Name:               WAP Binary XML (WBXML) document format

   +suffix:            +wbxml

   References:         [WBXML]

   Encoding considerations: WBXML is a binary encoding.

   Fragment identifier considerations:

                          The syntax and semantics of fragment
                          identifiers specified for +wbxml SHOULD be as
                          specified for "application/vnd.wap.wbxml".
                          (At publication of this document, there is no
                          fragment identification syntax defined for
                          "application/vnd.wap.wbxml".)

                          The syntax and semantics for fragment
                          identifiers for a specific "xxx/yyy+wbxml"
                          SHOULD be processed as follows:

                             For cases defined in +wbxml, where the
                             fragment identifier resolves per the +wbxml
                             rules, then as specified in +wbxml.




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                             For cases defined in +wbxml, where the
                             fragment identifier does not resolve per
                             the +wbxml rules, then as specified in "xxx
                             /yyy+wbxml".

                             For cases not defined in +wbxml, then as
                             specified in "xxx/yyy+wbxml".

   Interoperability considerations: n/a

   Security considerations: There are no security considerations
                       inherent in WBXML.  Each individual media type
                       registered with a +wbxml suffix can have
                       additional security considerations.

   Contact:            Apps Area Working Group (apps-discuss@ietf.org)

   Author/Change controller: The Apps Area Working Group has change
                       control over this registration.

3.6.  The +zip Structured Syntax Suffix

   The ZIP format is a public domain, cross-platform, interoperable file
   storage and transfer format, originally defined by PKWARE, Inc.; it
   supports compression and encryption and is used as the underlying
   representation by a variety of file formats.  The media type
   "application/zip" has been registered for such files.  The suffix
   "+zip" MAY be used with any media type whose representation follows
   that established for "application/zip".  The Message Type Structured
   Syntax Suffix registration form follows:

   Name:               ZIP file storage and transfer format

   +suffix:            +zip

   References:         [ZIP]

   Encoding considerations: ZIP is a binary encoding.

   Fragment identifier considerations:

                          The syntax and semantics of fragment
                          identifiers specified for +zip SHOULD be as
                          specified for "application/zip".  (At
                          publication of this document, there is no
                          fragment identification syntax defined for
                          "application/zip".)

                          The syntax and semantics for fragment
                          identifiers for a specific "xxx/yyy+zip"
                          SHOULD be processed as follows:



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                             For cases defined in +zip, where the
                             fragment identifier resolves per the +zip
                             rules, then as specified in +zip.

                             For cases defined in +zip, where the
                             fragment identifier does not resolve per
                             the +zip rules, then as specified in "xxx/
                             yyy+zip".

                             For cases not defined in +zip, then as
                             specified in "xxx/yyy+zip".

   Interoperability considerations: n/a

   Security considerations: ZIP files support two forms of encryption:
                       Strong Encryption and AES 128-bit, 192-bit and
                       256-bit encryption; see the specification for
                       further details.  Each individual media type
                       registered with a +zip suffix can have additional
                       security considerations.

   Contact:            Apps Area Working Group (apps-discuss@ietf.org)

   Author/Change controller: The Apps Area Working Group has change
                       control over this registration.

4.  IANA Considerations

   See the Message Type Structured Syntax Suffix registration forms in
   Section 3.1 - Section 3.6.

   The existing Structured Syntax Suffix registration for "+xml" is
   modified to include the following

   Fragment identifier considerations:

                          The syntax and semantics of fragment
                          identifiers specified for +xml SHOULD be as
                          specified for "application/xml".  (At
                          publication of this document, the fragment
                          identification syntax considerations for
                          "application/xml" are defined in [RFC3023],
                          sections 5 and 7.)

                          The syntax and semantics for fragment
                          identifiers for a specific "xxx/yyy+xml"
                          SHOULD be processed as follows:

                             For cases defined in +xml, where the
                             fragment identifier resolves per the +xml
                             rules, then as specified in +xml.



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                             For cases defined in +xml, where the
                             fragment identifier does not resolve per
                             the +xml rules, then as specified in "xxx/
                             yyy+xml".

                             For cases not defined in +xml, then as
                             specified in "xxx/yyy+xml".

5.  Security Considerations

   See the Security considerations sections found in the Message Type
   Structured Syntax Suffix registration forms from Section 3.1 -
   Section 3.5.

6.  References

6.1.  Normative References

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627, July 2006.

   [ITU.X690.2008]
              International Telecommunications Union, "Recommendation
              ITU-T X.690 | ISO/IEC 8825-1 (2008), ASN.1 encoding rules:
              Specification of basic encoding Rules (BER), Canonical
              encoding rules (CER) and Distinguished encoding rules
              (DER)", ITU-T Recommendation X.690, November 2008.

   [ITU.X891.2005]
              International Telecommunications Union, "Recommendation
              ITU-T X.891 | ISO/IEC 24824-1 (2007), Generic applications
              of ASN.1: Fast infoset", ITU-T Recommendation X.891, May
              2005.

   [WBXML]    Open Mobile Alliance, "Binary XML Content Format
              Specification", OMA Wireless Access Protocol
              WAP-192-WBXML-20010725-a, July 2001.

   [ZIP]      PKWARE, Inc., "APPNOTE.TXT - .ZIP File Format
              Specification", PKWARE .ZIP File Format Specification -
              Version 6.3.2, September 2007.

   [RFC2045]  Freed, N. and N.S. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part One: Format of Internet Message
              Bodies", RFC 2045, November 1996.

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

   [RFC3023]  Murata, M., St.  Laurent, S. and D. Kohn, "XML Media
              Types", RFC 3023, January 2001.

6.2.  Informative References

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   [I-D.ietf-appsawg-media-type-regs]
              Freed, N., Klensin, J. and T. Hansen, "Media Type
              Specifications and Registration Procedures", Internet-
              Draft draft-ietf-appsawg-media-type-regs-14, June 2012.

Appendix A.  Change History

   This section is to be removed before publication.

   draft-ietf-appsawg-media-type-suffix-regs-02 Added BER/DER security
                       considerations.
                                                Reworked fragment
                       identifier wording some more.

   draft-ietf-appsawg-media-type-suffix-regs-01 Reordered the sections.
                                                Cleaned up some MUSTard.
                                                Fixed some references.
                                                Added encoding
                       considerations.
                                                Reworked fragment
                       identifier wording.

   draft-ietf-appsawg-media-type-suffix-regs-00 Added the fragment
                       identifier consideration sections.
                                                Added a note about +xml
                       fragment identifier considerations.

   draft-hansen-media-type-suffix-regs-02 Added +zip.
                                          Fixed up the ISO document
                       references.
                                          Minor changes.

   draft-hansen-media-type-suffix-regs-01 Added +ber.
                                          Minor changes.

Author's Address

   Tony Hansen
   AT&T Laboratories
   200 Laurel Ave. South
   Middletown, NJ 07748
   USA

   Email: tony+sss@maillennium.att.com









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