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1
Introduction.
5
1.1 Terminology. 5
1.2 Normative. 5
1.3 Non Normative. 6
1.4 Namespace. 7
1.5 Conformance. 7
2
RM Policy Assertions. 8
2.1 Assertion Model 8
2.2 Normative Outline. 8
2.3 Assertion Attachment 9
2.4 Assertion Example. 11
2.5 Sequence Security Policy. 11
3
Security Considerations. 13
Appendix A. Schema. 14
Appendix B. Acknowledgments. 16
This specification defines a domain-specific
policy assertion for reliable messaging for use with WS-Policy and
WS-ReliableMessaging.
1.1 Terminology
The keywords "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 [KEYWORDS].
This specification uses the following syntax
to define normative outlines for messages:
·
The syntax appears as an XML instance, but values in italics
indicate data types instead of values.
·
Characters are appended to elements and attributes to indicate
cardinality:
o
"?" (0 or 1)
o
"*" (0 or more)
o
"+" (1 or more)
·
The character "|" is used to indicate a choice between
alternatives.
·
The characters "[" and "]" are used to indicate that contained
items are to be treated as a group with respect to cardinality or
choice.
·
An ellipsis (i.e. "...") indicates a point of extensibility that
allows other child, or attribute, content. Additional children
and/or attributes MAY be added at the indicated extension points
but MUST NOT contradict the semantics of the parent and/or owner,
respectively. If an extension is not recognized it SHOULD be
ignored.
·
XML namespace prefixes (see section 1.4) are used to indicate the
namespace of the element being defined.
Elements and Attributes defined by this
specification are referred to in the text of this document using
XPath 1.0 [XPATH 1.0] expressions.
Extensibility points are referred to using an extended version of
this syntax:
·
An element extensibility point is referred to using {any} in place
of the element name. This indicates that any element name can be
used, from any namespace other than the wsrm: namespace.
·
An attribute extensibility point is referred to using @{any} in
place of the attribute name. This indicates that any attribute name
can be used, from any namespace other than the wsrm: namespace.
1.2
Normative
[KEYWORDS]
S. Bradner, "Key
words for use in RFCs to Indicate Requirement Levels," RFC
2119, Harvard University, March 1997.
http://www.ietf.org/rfc/rfc2119.txt
[SOAP
1.1]
W3C Note, "SOAP: Simple Object
Access Protocol 1.1" 08 May 2000.
http://www.w3.org/TR/2000/NOTE-SOAP-20000508/
[SOAP 1.2]
W3C Recommendation, "SOAP Version
1.2 Part 1: Messaging Framework" June 2003.
http://www.w3.org/TR/2003/REC-soap12-part1-20030624/
[URI]
T. Berners-Lee, R. Fielding, L. Masinter, "Uniform Resource Identifiers (URI): Generic
Syntax," RFC 3986, MIT/LCS, U.C. Irvine, Xerox
Corporation, January 2005.
http://ietf.org/rfc/rfc3986
[WS-RM]
OASIS WS-RX Technical Committee Specification, "Web Services
Reliable Messaging (WS-ReliableMessaging)," April 2007.
http://docs.oasis-open.org/ws-rx/wsrm/v1.1/wsrm.pdf
[WSDL
1.1]
W3C Note, "Web Services
Description Language (WSDL 1.1)," 15 March 2001.
http://www.w3.org/TR/2001/NOTE-wsdl-20010315
[XML]
W3C Recommendation, "Extensible Markup
Language (XML) 1.0 (Fourth Edition)", September 2006.
http://www.w3.org/TR/REC-xml/
[XML-ns]
W3C Recommendation, "Namespaces in
XML," 14 January 1999.
http://www.w3.org/TR/1999/REC-xml-names-19990114/
[XML-Schema
Part1]
W3C Recommendation, "XML Schema Part 1:
Structures," October 2004.
http://www.w3.org/TR/xmlschema-1/
[XML-Schema
Part2]
W3C Recommendation, "XML Schema Part 2:
Datatypes," October 2004.
http://www.w3.org/TR/xmlschema-2/
[XPATH
1.0]
W3C Recommendation, "XML Path
Language (XPath) Version 1.0," 16 November 1999.
http://www.w3.org/TR/xpath
[RDDL
2.0]
Jonathan
Borden, Tim Bray, eds. “Resource
Directory Description Language (RDDL)
2.0,” January
2004
http://www.openhealth.org/RDDL/20040118/rddl-20040118.html
[SecurityPolicy] G. Della-Libra, et. al. "Web
Services Security Policy Language (WS-SecurityPolicy)", July
2005
http://specs.xmlsoap.org/ws/2005/07/securitypolicy/ws-securitypolicy.pdf
[WS-Policy]
W3C Member
Submission "Web Services Policy 1.2 - Framework", April
2006
http://www.w3.org/Submission/2006/SUBM-WS-Policy-20060425/
W3C Candidate Recommendation, "Web Services
Policy 1.5 - Framework," February 2007.
http://www.w3.org/TR/2007/CR-ws-policy-20070228
[WS-PolicyAttachment] W3C Member Submission
"Web Services Policy 1.2 - Attachment", April
2006
http://www.w3.org/Submission/2006/SUBM-WS-PolicyAttachment-20060425/
W3C Candidate Recommendation, "Web
Services Policy 1.5 - Attachment," February 2007.
http://www.w3.org/TR/2007/CR-ws-policy-attach-20070228
[WS-Security]
Anthony Nadalin, Chris Kaler, Phillip Hallam-Baker, Ronald
Monzillo, eds. "OASIS
Web Services Security: SOAP Message Security 1.0 (WS-Security
2004)", OASIS Standard 200401, March 2004.
http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0.pdf
Anthony Nadalin, Chris Kaler, Phillip Hallam-Baker, Ronald
Monzillo, eds. "OASIS
Web Services Security: SOAP Message Security 1.1 (WS-Security
2004)", OASIS Standard 200602, February 2006.
http://docs.oasis-open.org/wss/v1.1/wss-v1.1-spec-os-SOAPMessageSecurity.pdf
The XML namespace [XML-ns] URI that
MUST be used by implementations of this specification is:
Dereferencing the above URI will produce the
Resource Directory Description Language [RDDL
2.0] document that describes this namespace.
Table 1 lists the XML namespaces that are used
in this specification. The choice of any namespace prefix is
arbitrary and not semantically significant. The assertions defined
within this specification have been designed to work independently
of a specific version of WS-Policy. At the time of the publication
of this specification the versions of WS-Policy known to correctly
compose with this specification are WS-Policy 1.2 and 1.5. Within
this specification the use of the namespace prefix wsp refers
generically to the WS-Policy namespace, not a specific version.
Table 1
|
Prefix
|
Namespace
|
Specification
|
|
wsdl
|
http://schemas.xmlsoap.org/wsdl/
|
[WSDL
1.1]
|
|
wsrmp
|
http://docs.oasis-open.org/ws-rx/wsrmp/200702
|
This specification.
|
|
wsu
|
http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd
|
WS-Security-Utility
Schema
|
The normative schema
for WS-ReliableMessaging can be found linked from the namespace
document that is located at the namespace URI specified
above.
All sections explicitly noted as examples are
informational and are not to be considered normative.
An implementation is not compliant with this
specification if it fails to satisfy one or more of the MUST or
REQUIRED level requirements defined herein. A SOAP Node MUST NOT
use the XML namespace identifier for this specification (listed in
section 1.4) within SOAP Envelopes unless it is compliant with this
specification.
Normative text within this specification takes
precedence over normative outlines, which in turn take precedence
over the XML Schema [XML-Schema Part1,
XML-Schema
Part2] descriptions.
WS-Policy Framework and WS-Policy Attachment
[WS-PolicyAttachment]
collectively define a framework, model and grammar for expressing
the requirements, and general characteristics of entities in an XML
Web services-based system. To enable an RM Destination and an RM
Source to describe their requirements for a given Sequence, this
specification defines a single RM policy assertion that leverages
the WS-Policy framework.
The RM policy assertion indicates that the RM
Source and RM Destination MUST use WS-ReliableMessaging to ensure
reliable delivery of messages. Specifically, the
WS-ReliableMessaging protocol determines invariants maintained by
the reliable messaging endpoints and the directives used to track
and manage the delivery of a Sequence of messages.
The normative outline for the RM assertion
is:
<wsrmp:RMAssertion [wsp:Optional="true"]? ... >
<wsp:Policy>
[ <wsrmp:SequenceSTR/> |
<wsrmp:SequenceTransportSecurity/> ] ?
<wsrmp:DeliveryAssurance>
<wsp:Policy>
[
<wsrmp:ExactlyOnce/> |
<wsrmp:AtLeastOnce/> |
<wsrmp:AtMostOnce/> ]
<wsrmp:InOrder/>
?
</wsp:Policy>
</wsrmp:DeliveryAssurance> ?
</wsp:Policy>
...
</wsrmp:RMAssertion>
The following describes the content model of
the RMAssertion
element.
/wsrmp:RMAssertion
A policy assertion
that specifies that WS-ReliableMessaging protocol MUST be used when
sending messages.
/wsrmp:RMAssertion/@wsp:Optional="true"
Per WS-Policy,
this is compact notation for two policy alternatives, one with and
one without the assertion. The intuition is that the behavior
indicated by the assertion is optional, or in this case, that
WS-ReliableMessaging MAY be used.
/wsrmp:RMAssertion/wsp:Policy
This required
element allows for the inclusion of nested policy
assertions.
/wsrmp:RMAssertion/wsp:Policy/wsrmp:SequenceSTR
When present, this
assertion defines the requirement that an RM Sequence MUST be bound
to an explicit token that is referenced from a wsse:SecurityTokenReference in
the CreateSequence message. See
section 2.5.1.
/wsrmp:RMAssertion/wsp:Policy/wsrmp:SequenceTransportSecurity
When present, this
assertion defines the requirement that an RM Sequence MUST be bound
to the session(s) of the underlying transport-level protocol used
to carry the CreateSequence and
CreateSequenceResponse message.
When present, this assertion MUST be used in conjunction with
the sp:TransportBinding assertion,
see section 2.5.2.
/wsrmp:RMAssertion/wsp:Policy/wsrmp:DeliveryAssurance
This expression,
which may be omitted, describes the message delivery quality of
service between the RM and application layer. When used by an RM
Destination it expresses the delivery assurance in effect between
the RM Destination and its corresponding application destination,
and it also indicates requirements on any RM Source that transmits
messages to this RM destination. Conversely when used by an RM
Source it expresses the delivery assurance in effect between the RM
Source and its corresponding application source, as well as
indicating requirements on any RM Destination that receives
messages from this RM Source. In either case the delivery assurance
does not affect the messages transmitted on the wire. Absence of
this expression from a wsrmp:RMAssertion
policy assertion simply means that the endpoint has chosen not to
advertise its delivery assurance characteristics.
Note that when there are multiple policy alternatives of the RM
Assertion, the Delivery Assurance on each MUST NOT
conflict.
/wsrmp:RMAssertion/wsp:Policy/wsrmp:DeliveryAssurance/wsp:Policy
This required
element identifies additional requirements for the use of
the wsrmp:DeliveryAssurance.
/wsrmp:RMAssertion/wsp:Policy/wsrmp:DeliveryAssurance/wsp:Policy/wsrmp:ExactlyOnce
This expresses the
ExactlyOnce Delivery Assurance defined in [WS-RM].
/wsrmp:RMAssertion/wsp:Policy/wsrmp:DeliveryAssurance/wsp:Policy/wsrmp:AtLeastOnce
This expresses the
AtLeastOnce Delivery Assurance defined in [WS-RM].
/wsrmp:RMAssertion/wsp:Policy/wsrmp:DeliveryAssurance/wsp:Policy/wsrmp:AtMostOnce
This expresses the
AtMostOnce Delivery Assurance defined in [WS-RM].
/wsrmp:RMAssertion/wsp:Policy/wsrmp:DeliveryAssurance/wsp:Policy/wsrmp:InOrder
This expresses the
InOrder Delivery Assurance defined in [WS-RM].
/wsrmp:RMAssertion/{any}
This is an
extensibility mechanism to allow different (extensible) types of
information, based on a schema, to be passed.
/wsrmp:RMAssertion/@{any}
This is an
extensibility mechanism to allow different (extensible) types of
information, based on a schema, to be passed.
The RM policy assertion is allowed to have the
following Policy Subjects [WS-PolicyAttachment]:
·
Endpoint Policy Subject
·
Message Policy Subject
WS-PolicyAttachment defines a set of WSDL/1.1
policy attachment points for each of the above Policy Subjects.
Since an RM policy assertion specifies a concrete behavior, it MUST
NOT be attached to the abstract WSDL policy attachment points.
The following is the list of WSDL/1.1 elements
whose scope contains the Policy Subjects allowed for an RM policy
assertion but which MUST NOT have RM policy assertions
attached:
·
wsdl:message
·
wsdl:portType/wsdl:operation/wsdl:input
·
wsdl:portType/wsdl:operation/wsdl:output
·
wsdl:portType/wsdl:operation/wsdl:fault
·
wsdl:portType
The following is the list of WSDL/1.1 elements
whose scope contains the Policy Subjects allowed for an RM policy
assertion and which MAY have RM policy assertions attached:
·
wsdl:port
·
wsdl:binding
·
wsdl:binding/wsdl:operation/wsdl:input
·
wsdl:binding/wsdl:operation/wsdl:output
·
wsdl:binding/wsdl:operation/wsdl:fault
If an RM policy assertion is attached to any
of:
·
wsdl:binding/wsdl:operation/wsdl:input
·
wsdl:binding/wsdl:operation/wsdl:output
·
wsdl:binding/wsdl:operation/wsdl:fault
then an RM policy assertion, specifying
wsp:Optional=”true”
MUST be attached to the corresponding wsdl:binding or wsdl:port, indicating that the
endpoint supports WS-RM. Any messages, regardless of whether they
have an attached Message Policy Subject RM policy assertion, MAY be
sent to that endpoint using WS-RM. Additionally, the receiving
endpoint MUST NOT reject any message belonging to a Sequence,
simply because there was no Message Policy Subject RM policy
assertion attached to that message. There might be certain RM
implementations that are incapable of applying RM Quality of
Service (QoS) semantics on a per-message basis. In order to ensure
the broadest interoperability, when an endpoint decorates its WSDL
with RM policy assertions using Message Policy Subject, it MUST
also be prepared to accept that all messages sent to that endpoint
might be sent within the context of an RM Sequence, regardless of
whether the corresponding wsdl:input, wsdl:output or wsdl:fault had
an attached RM policy assertion.
Rather than turn away messages that were
unnecessarily sent with RM semantics, the receiving endpoint
described by the WSDL MUST accept these messages.
By attaching an RM policy assertion that
specifies wsp:Optional="true" to the
corresponding endpoint that has attached RM policy assertions at
the Message Policy Subject level, the endpoint is describing the
above constraint in policy.
In the case where an optional RM Assertion
applies to an output message, there is no requirement on the client
to support an RM Destination implementation
Table 2 lists an example use of the RM policy
assertion.
Table 2: Example
policy with RM policy assertion
(01)<wsdl:definitions
(02) targetNamespace="example.com"
(03) xmlns:tns="example.com"
(04)
xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
(05)
xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"
(06)
xmlns:wsrmp="http://docs.oasis-open.org/ws-rx/wsrmp/200702"
(07)
xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
(08)
(09)
<wsp:UsingPolicy wsdl:required="true" />
(10)
(11)
<wsp:Policy wsu:Id="MyPolicy" >
(12) <wsrmp:RMAssertion>
(13) <wsp:Policy/>
(14) </wsrmp:RMAssertion>
(15) <!-- omitted assertions -->
(16)
</wsp:Policy>
(17)
(18) <!--
omitted elements -->
(19)
(20)
<wsdl:binding name="MyBinding" type="tns:MyPortType" >
(21) <wsp:PolicyReference URI="#MyPolicy" />
(22) <!-- omitted elements -->
(23)
</wsdl:binding>
(24)
(25)</wsdl:definitions>
Line (09) in Table 2 indicates that WS-Policy
is in use as a required extension.
Lines (11-16) are a policy expression that
includes a RM policy assertion (lines 12-14) to indicate that
WS-ReliableMessaging must be used.
Lines (20-23) are a WSDL binding. Line (21)
indicates that the policy in lines (11-16) applies to this binding,
specifically indicating that WS-ReliableMessaging must be used over
all the messages in the binding.
WS-SecurityPolicy [SecurityPolicy] provides a framework and
grammar for expressing the security requirements and
characteristics of entities in a XML web services based system. The
following assertions MAY be used in conjunction with
WS-SecurityPolicy to express additional security requirements
particular to RM Sequences.
This version of the RM assertion includes the
requirement that an RM Sequence MUST be bound to an explicit token
that is referenced from a wsse:SecurityTokenReference in
the CreateSequence
message.
This assertion MUST apply to [Endpoint Policy
Subject]. The normative outline for this form of the Sequence STR
Assertion is:
<wsrmp:RMAssertion [wsp:Optional="true"]? ...>
<wsp:Policy>
<wsrmp:SequenceSTR/>
<wsp:Policy>
</wsrmp:RMAssertion>
The following describes the content model of
the SequenceSTR
element.
/wsrmp:SequenceSTR
A policy
assertion that specifies security requirements which MUST be used
with an RM Sequence that are particular to WS-RM and beyond what
can be expressed in WS-SecurityPolicy.
This version of the RM assertion includes the
requirement that an RM Sequence MUST be bound to the session(s) of
the underlying transport-level security protocol (e.g. SSL/TLS)
used to carry the CreateSequence and CreateSequenceResponse
messages.
This assertion MUST apply to [Endpoint Policy
Subject]. This assertion MUST be used in conjunction with the
sp:TransportBinding
assertion that requires the use of some transport-level security
mechanism (e.g. sp:HttpsToken).
The normative outline for this form of the RM
Assertion with the Sequence Transport Security Assertion is:
<wsp:Policy>
<wsp:ExactlyOne>
<wsp:All>
<wsrm:RMAssertion
[wsp:Optional="true"]> ...>
<wsp:Policy>
<wsrmp:SequenceTransportSecurity/>
</wsp:Policy>
</wsrm:RMAssertion>
<sp:TransportBinding ...>
...
</sp:TransportBinding>
<wsp:All>
<wsp:ExactlyOne>
</wsp:Policy>
The following describes the content model of
the SequenceTransportSecurity
element.
/wsrmp:SequenceTransportSecurity
A policy
assertion that specifies that any Sequences targeted to the
indicated endpoint MUST be bound to the underlying session(s) of
the transport-level security used to carry messages related to the
Sequence.
This form of the RM Assertion says that an
endpoint MAY have RM as an option but always requires HTTPS to be
used. All the SequenceTransportSecurity assertion indicates is that
RM's rules for protecting the Sequence over TLS are followed.
It is strongly RECOMMENDED that policies and
assertions be signed to prevent tampering.
It is RECOMMENED that policies SHOULD NOT be
accepted unless they are signed and have an associated security
token to specify the signer has proper claims for the given policy.
That is, a relying party shouldn't rely on a policy unless the
policy is signed and presented with sufficient claims to pass the
relying parties acceptance criteria.
It should be noted that the mechanisms
described in this document could be secured as part of a SOAP
message using WS-Security [WS-Security]
or embedded within other objects using object-specific security
mechanisms.
A normative copy of the XML Schema [XML-Schema Part1, XML-Schema Part2] description for this
specification may be retrieved from the following address:
The following copy is provided for
reference.
<?xml
version="1.0" encoding="UTF-8"?>
<!-- Copyright(C) OASIS(R) 1993-2007. All Rights Reserved.
OASIS trademark, IPR and other policies
apply. -->
<xs:schema
xmlns:tns="http://docs.oasis-open.org/ws-rx/wsrmp/200702"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://docs.oasis-open.org/ws-rx/wsrmp/200702"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<xs:element name="RMAssertion">
<xs:complexType>
<xs:sequence>
<xs:any
namespace="##other" processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute
namespace="##any" processContents="lax"/>
</xs:complexType>
</xs:element>
<xs:element name="SequenceSTR">
<xs:complexType>
<xs:sequence/>
<xs:anyAttribute
namespace="##any" processContents="lax"/>
</xs:complexType>
</xs:element>
<xs:element name="SequenceTransportSecurity">
<xs:complexType>
<xs:sequence/>
<xs:anyAttribute
namespace="##any" processContents="lax"/>
</xs:complexType>
</xs:element>
<xs:element name="DeliveryAssurance">
<xs:complexType>
<xs:sequence>
<xs:any
namespace="##any" processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="ExactlyOnce">
<xs:complexType>
<xs:sequence/>
</xs:complexType>
</xs:element>
<xs:element name="AtLeastOnce">
<xs:complexType>
<xs:sequence/>
</xs:complexType>
</xs:element>
<xs:element name="AtMostOnce">
<xs:complexType>
<xs:sequence/>
</xs:complexType>
</xs:element>
<xs:element
name="InOrder">
<xs:complexType>
<xs:sequence/>
</xs:complexType>
</xs:element>
</xs:schema>
This document is based on initial contribution
to OASIS WS-RX Technical Committee by the following authors:
