- From: Mark Baker <distobj@acm.org>
- Date: Thu, 3 Jan 2002 21:56:54 -0500 (EST)
- To: xml-dist-app@w3.org
Here it is. It has *not* been submitted to as an internet draft yet,
so it should not be referred to using internet-draft naming. i.e. it
will continue to be called draft-baker-soap-media-reg-00.txt until
such time as it is published as a draft.
The security section is likely going to be the hot topic. We've managed
to avoid these issues so far, but that had to come to an end at some
point. 8-)
Also, the "envelope" parameter is in there, but not one relating to
encoding.
==snip==
Internet-Draft Mark Baker
Planetfred, Inc.
Mark Nottingham
January XX, 2002
The "application/soap+xml" media type
draft-baker-soap-media-reg-00.txt
Status of this Memo
This document is an Internet-Draft and is subject to all provisions
of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire in July, 2003.
Abstract
This document defines the "application/soap+xml" media type which can
be used to describe SOAP 1.2 messages serialized as XML.
1. Introduction
SOAP 1.2 is an XML Infoset[INFOSET] based protocol at the core of
which is an envelope that defines a framework for describing what is
in a message and how to process it, and a binding framework for
exchanging messages using an underlying protocol.
By being based on the XML Infoset, and not XML 1.0 [XML] itself, SOAP
permits alternate serializations of messages. The
"application/soap+xml" media type can be used to describe those SOAP
messages produced with the XML 1.0 serialization.
2. Registration
MIME media type name: application
MIME subtype name: soap+xml
Required parameters: none
Optional parameters:
charset
This parameter has identical semantics to the charset parameter
of the "application/xml" media type as specified in [XMLMIME].
action
See Section 6 of this document.
envelope
This parameter can be used to specify the SOAP envelope URI,
permitting SOAP processors to decide whether they can attempt to
process the envelope or not.
Encoding considerations:
Identical to those of "application/xml" as described in [XMLMIME],
Section 3.2.
Security considerations:
See Section 3 of this document.
Interoperability considerations:
See Section 4 of this document.
Published specification:
See [SOAP12P1] and [SOAP12P2].
Applications which use this media type:
No known applications currently use this media type.
Additional information:
Magic number:
There is no single initial byte sequence that is always present
for SOAP messages. Section 5 below gives some context for why
recognizing a SOAP message without any metadata is problematic,
and some guidelines on how the XML 1.0 serialization of the SOAP
envelope may be recognized.
File extension:
SOAP messages are not required or expected to be stored as
files.
Macintosh File Type code: TEXT
Person & email address to contact for further information:
Mark Baker <mbaker@planetfred.com>
Intended usage: COMMON
Author/Change controller:
The SOAP 1.2 specification set is a work product of the World Wide
Web Consortium's XML Protocol Working Group. The W3C has change
control over these specifications.
3. Security considerations
From a security perspective, SOAP can be seen to be used in two
different ways; tunneled, and non-tunneled.
3.1 Non-tunneled
The non-tunneled use of SOAP is as an XML Infoset based envelope whose
hop-by-hop transfer semantics are inherited from the application
protocol used for that hop.
In this use, the binding of SOAP to that protocol extends the
application semantics of the protocol without modifying or otherwise
disrupting the existing semantics. This includes the security model.
For example, when bound to HTTP using the SOAP 1.2 default HTTP
binding, the transfer of a SOAP envelope is performed with HTTP POST
semantics, and the security implications are the same as for any other
HTTP POST, up to the point where the SOAP processing model takes over.
The SOAP processing model itself is entirely innocuous from a security
perspective. The semantic extensions it provides, in addition to the
syntactic ones provided by the envelope, are;
o "actor", used to target headers to SOAP intermediaries that
understand its URI value
o "mustUnderstand", used to require that a SOAP header must be
understood by a SOAP intermediary, or the message is rejected
"actor" values are URIs, however there are no requirements that a SOAP
processor attempt to resolve them, so no security issues should result
from their use. Hostile or broken SOAP intermediaries that don't
conform to the processing model may break the end-to-end contract
formed by the use of the "actor" attribute, but that is a known
problem in all environments with intermediaries. There is no known
security problem specific to the "actor" attribute in this respect.
"mustUnderstand" has no known security issues, outside the generic
ones about intermediaries discussed previously in regards to "actor".
3.2 Tunneled
Another use of SOAP is as a framework for building and deploying new
protocols, tunneled over the underlying protocol to which it is
bound. If the underlying protocol is an application protocol, then
any security model of that protocol would be disregarded (by
definition of "tunnel"). It will be up to the designer of the new
protocol to ensure that its semantics are safe.
That SOAP explicitly supports tunneling would at first glance appear
to be a problem. However, as tunneling over POST is already fairly
common (including IPP [IPP], on the IETF Internet standards track),
the possibility of consolidating future tunneling practice within a
framework such as SOAP should help security in the long run.
As a worst case from a security perspective, if SOAP were used only
for tunneling, it would be no worse than the tunneling that exists
today.
4. Interoperability considerations
There are several factors affecting a SOAP processor's ability to
successfully process a SOAP message. These are itemized in Section
4.4.5 of [SOAP12P1].
One of these factors, the SOAP envelope namespace, is optionally
made available to processors through the parameter "envelope"
described in Section 2.
5. Recognizing SOAP messages
SOAP 1.2 does not require or assume that SOAP 1.2 messages have any
particular serialization, making it impossible to determine (in the
absence of other information) when a chunk of data is a SOAP 1.2
message or not.
However, for the case of the XML 1.0 serialization of SOAP 1.2
messages, the following best describes how these messages may be
recognized.
The root element of the message will always be named "envelope" with
the namespace "http://www.w3.org/2001/12/soap-envelope". However,
this may be expressed in a couple of ways;
o with an xmlns declaration on the root element
o with a prefix-adorned xmlns declaration on the root element
where "envelope" is so prefixed
6. The "action" parameter
SOAP 1.1 [SOAP11] introduced the HTTP SOAPAction header, which was
designed to be used to indicate the "intent" of the SOAP message. Its
value is a URI reference, and its existence was to be used to
unambiguously identify SOAP messages tranferred with HTTP. It was
required because SOAP 1.1 used the generic "text/xml" media type,
preventing that same information from being communicated on the media
type where it might normally reside.
As SOAP 1.2 is defining its own media type, the possibility of using
a parameter on that media type to convey the same information as is
done with SOAPAction, now exists. "action" is that parameter.
Its semantics are identical to that of the SOAPAction header of SOAP
1.2, not SOAP 1.1 (a key difference being that it is optional in SOAP
1.2). The following is a mapping of the meanings of the various uses
of SOAPAction (as described in [SOAP12P2]) to the "action" parameter;
SOAPAction use | "action" parameter
------------------------------+------------------------
|
SOAPAction: "http://foo/bar" | action="http://foo/bar"
|
SOAPAction: "myapp.sdl" | action="myapp.sdl"
|
SOAPAction: "" | action=""
|
7. Fragment identifiers
No meaning is associated with fragment identifiers for content
described by the "application/soap+xml" media type.
8. Authors' Addresses
Mark A. Baker
Planetfred, Inc.
44 Byward Market, Suite 240
Ottawa, Ontario, CANADA. K1N 7A2
tel:+1-613-789-1818
mailto:mbaker@planetfred.com
Mark Nottingham
mailto:mnot@mnot.net
9. References
[XML] "Extensible Markup Language (XML) 1.0", W3C Recommendation,
February 1998. Available at <http://www.w3.org/TR/REC-xml>
(or <http://www.w3.org/TR/2000/REC-xml-20001006>).
[INFOSET] "XML Information Set", W3C Recommendation, 24 October 2001,
Available at <http://www.w3.org/TR/xml-infoset> (or
<http://www.w3.org/TR/2001/REC-xml-infoset-20011024>).
[XMLMIME] Murata, M., St.Laurent, S., Kohn, D., "XML Media Types",
RFC 3023, January 2001.
[SOAP11] Box, D., Ehnebuske, D., Kakivaya, G., Layman, A., Mendelsohn,
N., Nielsen, H., Thatte, S. and D. Winer, "Simple Object Access
Protocol (SOAP) 1.1", May 2000, <http://www.w3.org/TR/2000/
NOTE-SOAP-20000508>.
[SOAP12P1] TBD.
[SOAP12P2] TBD.
[XMLBASE] "XML Base", W3C Recommendation, 27 June 2001. Available at
<http://www.w3.org/TR/xml-base/> (or
<http://www.w3.org/TR/2001/REC-xmlbase-20010627/>).
[IPP] Herriot, R., Butler, S., Moore, P., Turner, R. and J. Wenn,
"Internet Printing Protocol/1.1: Encoding and Transport",
RFC 2910, September 2000.
MB
--
Mark Baker, Chief Science Officer, Planetfred, Inc.
Ottawa, Ontario, CANADA. mbaker@planetfred.com
http://www.markbaker.ca http://www.planetfred.com
Received on Thursday, 3 January 2002 21:56:24 UTC