[Pgi-wg] [gridshib-user] comments regarding a VOMS-SAML token--ANY plan to make VOMS SAML assertion be compatible with WS-Security SAML Token profile?

Duane Merrill dgm4d at virginia.edu
Mon Mar 30 16:37:44 CDT 2009 

BTW, the original PGI Strawman contains some considerations for what exactly
what you are discussing, regarding a SOAP-SAML-attribute profile.

-Duane




2009/3/30 weizhong qiang <weizhongqiang at gmail.com>

> hi,
>
> On Mon, Mar 30, 2009 at 6:46 PM, Tom Scavo <trscavo at gmail.com> wrote:
>
>> On Mon, Mar 30, 2009 at 12:06 PM, weizhong qiang
>> <weizhongqiang at gmail.com> wrote:
>> >
>> > For a SAML Token which is compliant to SAML V1.1...
>> >
>> > For a SAML Token which is compliant to SAML V2.0...
>>
>> It should be noted that these examples from the WSS SAML Token Profile
>> are not normative.  Indeed, the SAML V2.0 token is not even
>> schema-valid.
>
>
> Thanks. I did not know that. But I also thought this part of specification
> in WS-Security is not so clearly defined.
>
>
>>
>>
>> > 1. The signature for <saml:Reponse> could also be necessary, even though
>> the
>> > integrity is guaranteed by TLS.
>>
>> That's unlikely, I think.  The Response is consumed by the requester
>> (it does not appear in the SOAP header) so there's really no need
>> (that I can see) to sign the Response if the request is made over
>> mutually authenticated TLS.
>>
>> > 2. xml attribute  xsi:type="saml2:KeyInfoConfirmationDataType" could be
>> > necessary for <saml2:SubjectConfirmationData/>
>>
>> As I recall, that type declaration is optional, but yes, its use is
>> recommended.
>>
>> > 3. <saml:SubjectConfirmation> element contains a <ds:X509Certificate>
>> > element, but it probably be better to just contain a <ds:KeyValue>,
>> since
>> > the certificates chain of the "subject" is already supposed to be
>> verified
>> > by the third-party authority (in this case, it is voms saml service),
>> and
>> > then this public key is used to sign the soap message afterwards.
>>
>> I don't see what the certificate chain has to do with the use of the
>> <ds:X509Certificate> element in this case.  The latter requires the
>> presenter to prove possession of the private key corresponding to the
>> public key bound to the certificate.  What does that have to do with
>> the presented certificate chain?
>
> two types of verification here:
> 1. verify that "possession of the private key corresponding to the public
> key bound to the certificate"
> 2. verify that "possession of the private key corresponding to the public
> key bound to the certificate" + verify that the certificate is signed by
> trusted authority (in this case verification of certificates chain is
> needed.)
>
> What I meant is for SAML Token profile, step 2 is not needed.
>
>
>>
>>
>> > For SOAP
>> > message verification on the rely-party side, the rely-party do not need
>> to
>> > verify the certificates chain of "subject".
>>
>> I'm not sure I follow you.  How does the presenter of the SOAP request
>> (with SAML token in the SOAP header) authenticate to the SOAP
>> responder?
>
>
> "authentication" here could not be accurate.
> SOAP presentor authenticates (via TLS, or SOAP message authentication by
> using X.509 token) to 3-party authority (trusted by rely-party), and gets
> back SAML Token (with the presentor's public key, or certificate inside as
> part of <saml:SubjectConfirmation>); Then uses its' own private key to sign
> soap message; Afterwards rely-party can verify the signature to SOAP message
> (simple verification is needed, just verify that the private key which
> signes the SOAP message corresponds to the public key in the
> <saml:SubjectConfirmation>), as well as verify the signature to
> <saml:Assertion> (simple verification + verifying the certificate in
> <ds:Signature> is trusted).
>
>
>
>>
>>
>> > <ds:KeyValue> is also convinient for proxy certificate, in my opinion.
>>
>> I don't see what <ds:KeyValue> gains you in this case, but I may be
>> missing something.  Unless you can provide a good reason for using
>> <ds:KeyValue>, I recommend <ds:X509SubjectName> or <ds:X509SKI>, in
>> that order.  The <ds:X509SubjectName> element is simplest for proxy
>> certificates, I think.  It is equivalent to the subject confirmation
>> implied in VOMS proxies, in fact.
>
>
> Probably <ds:KeyValue> can not gain more than <ds:X509Certificate>
> (formerly I supposed the <ds:KeyValue> should be standarlized) . But by
> using <ds:X509SubjectName>,  what is the way to get the public key, which is
> required when verifying the signature to SOAP message.
>
>
>>
>>
>> In any event, I should point out that the SAML V2.0 Holder-of-Key
>> Assertion Profile is now in its formal Public Review period, and it
>> does not profile <ds:KeyValue>, so if you think that's an error of
>> omission, it would be good if you could submit a public comment to
>> that effect.
>>
>>
>> http://lists.oasis-open.org/archives/security-services/200903/msg00062.html
>
>
> Is any of the draft you mentioned in this link supposed to update/replace
> the WS-Security SAML Token 1.1 profile?
>
>
> Weizhong Qiang
>
>
>
>>
>>
>> > 4. Use <saml:Statement> instead of <saml:AttributeStatement>.
>>
>> Why?  The <saml:Statement> element is abstract so that would require a
>> type.  What type do you recommend (if not
>> saml:AttributeStatementType)?
>
>
>>
>> Tom
>>
>> > On Mon, Mar 30, 2009 at 5:00 PM, Tom Scavo <trscavo at gmail.com> wrote:
>> >>
>> >> Hi Weizhong,
>> >>
>> >> Can you outline why you think the VOMS SAML assertion is not
>> >> compatible with the WSS SAML Token Profile?
>> >>
>> >> Thanks,
>> >> Tom
>> >>
>> >> PS. The comments quoted below mostly refer to a VOMS SAML assertion
>> >> bound to an X.509 proxy certificate (but the requirements are not the
>> >> same as a VOMS SAML assertion bound to SOAP header).
>> >>
>> >> On Mon, Mar 30, 2009 at 10:25 AM, weizhong qiang
>> >> <weizhongqiang at gmail.com> wrote:
>> >> > hi voms folks, all,
>> >> > The current voms SAML assertion is not compatible with WS-Security
>> SAML
>> >> > Token profile. I would ask is there any plan to change it to make it
>> be
>> >> > compatible? I ask this because I think if so, the SAML assertion can
>> be
>> >> > used
>> >> > for SOAP message layer authentication, other than just including SAML
>> >> > attribute assertion.
>> >> >
>> >> >
>> >> > Thanks
>> >> > Weizhong Qiang
>> >> >
>> >> >
>> >> > On Tue, Feb 10, 2009 at 5:21 AM, Tom Scavo <trscavo at gmail.com>
>> wrote:
>> >> >>
>> >> >> Thanks to Benjamin for posting this VOMS-SAML response to gt-user.
>>  A
>> >> >> critique (of the SAML, not Benjamin :) follows.
>> >> >>
>> >> >> - Note that the output is a <samlp:Response> element, not a
>> >> >> <saml:Assertion> element.  This is wrong.  The requester must
>> consume
>> >> >> the response.  Not sure why this isn't happening.
>> >> >>
>> >> >> - The value of the <saml:Issuer> element in the response is a DN but
>> >> >> the Format XML attribute is missing.  This is a bug.  The default
>> >> >> Format is "unspecified" but clearly this is not.
>> >> >>
>> >> >> - Second-level status codes are desirable so they can be echoed on
>> the
>> >> >> command line (if any).
>> >> >>
>> >> >> - Same comment about the <saml:Issuer> element in the assertion.
>> >> >>
>> >> >> - The use of SAML metadata requires that the Format on the
>> >> >> <saml:Issuer> element be "entity" but clearly it is not.  Thus the
>> use
>> >> >> of SAML metadata by the relying party is precluded.
>> >> >>
>> >> >> - Don't know if Shibboleth/OpenSAML can verify the signature (which
>> is
>> >> >> tricky business).  This is a future experiment that needs to be
>> done.
>> >> >>
>> >> >> - The <saml:SubjectConfirmation> element contains a
>> >> >> <ds:X509Certificate> element, which precludes the binding of this
>> >> >> holder-of-key assertion to a proxy certificate.  This is a bug.  Use
>> a
>> >> >> <ds:X509SubjectName> element instead (which causes the NameID itself
>> >> >> to be redundant).
>> >> >>
>> >> >> - If the assertion is bound to a proxy certificate, the NotBefore
>> and
>> >> >> NotOnOrAfter attributes are redundant and superfluous.  In fact,
>> they
>> >> >> may be wrong since they must agree with the NotBefore and
>> NotOnOrAfter
>> >> >> fields of the proxy.
>> >> >>
>> >> >> - Since the client authenticated directly to the server, a
>> >> >> <saml:AuthnStatement> is desirable (not required, but potentially
>> >> >> useful at the relying party).
>> >> >>
>> >> >> - The NameFormat XML attribute on the <saml:Attribute> element
>> should
>> >> >> be "uri" not "unspecified".
>> >> >>
>> >> >> - The "xsi:" prefix on the <saml:AttributeValue> element is
>> undefined.
>> >> >>  This is a bug.
>> >> >>
>> >> >> - The <saml:AttributeValue> elements do not conform to the XACML
>> >> >> Attribute Profile (actually, I don't think the attributes conform to
>> >> >> *any* SAML V2.0 attribute profile).
>> >> >>
>> >> >> Hope this helps,
>> >> >> Tom
>> >> >>
>> >> >> ---------- Forwarded message ----------
>> >> >> From: Benjamin Henne <henne at rvs.uni-hannover.de>
>> >> >> Date: Wed, Feb 4, 2009 at 1:59 AM
>> >> >> Subject: Re: [gt-user] SAML based VOMS Server
>> >> >> To: Tom Scavo <trscavo at gmail.com>
>> >> >> Cc: GT User <gt-user at globus.org>
>> >> >>
>> >> >>
>> >> >> <Response xmlns="urn:oasis:names:tc:SAML:2.0:protocol"
>> >> >> xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
>> >> >> ID="_d01d46b7-d16a-4ae8-b9bb-beb8844838b6"
>> >> >> InResponseTo="_qwertyuiopasdfghjklzxcvbn"
>> >> >> IssueInstant="2008-10-16T19:03:57.922Z" Version="2.0">
>> >> >>  <saml:Issuer
>> >> >>
>> >> >> xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">CN=
>> voms3.gridlab.uni-hannover.de
>> ,OU=UniHannover,O=GermanGrid,C=DE</saml:Issuer>
>> >> >>  <Status>
>> >> >>   <StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/>
>> >> >>  </Status>
>> >> >>  <saml:Assertion xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
>> >> >> ID="_81b685e5-4650-4ba9-b1c6-0ed957cc33ac"
>> >> >> IssueInstant="2008-10-16T19:03:57.920Z" Version="2.0">
>> >> >>
>> >> >>
>> >> >> <saml:Issuer>CN=voms3.gridlab.uni-hannover.de
>> ,OU=UniHannover,O=GermanGrid,C=DE</saml:Issuer>
>> >> >>   <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
>> >> >> <ds:SignedInfo>
>> >> >> <ds:CanonicalizationMethod
>> >> >> Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
>> >> >> <ds:SignatureMethod
>> >> >> Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
>> >> >> <ds:Reference URI="#_81b685e5-4650-4ba9-b1c6-0ed957cc33ac">
>> >> >> <ds:Transforms>
>> >> >> <ds:Transform
>> >> >> Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
>> >> >> <ds:Transform
>> >> >>
>> >> >> Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#
>> "><ec:InclusiveNamespaces
>> >> >> xmlns:ec="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="ds
>> saml
>> >> >> xs"/></ds:Transform>
>> >> >> </ds:Transforms>
>> >> >> <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1
>> "/>
>> >> >> <ds:DigestValue>j55K/cn8GQNuTQ52Kr3r0NGRJ0w=</ds:DigestValue>
>> >> >> </ds:Reference>
>> >> >> </ds:SignedInfo>
>> >> >> <ds:SignatureValue>
>> >> >> ...
>> >> >> </ds:SignatureValue>
>> >> >>
>> >> >>
>> >> >>
>> <ds:KeyInfo><ds:X509Data><ds:X509Certificate>...</ds:X509Certificate></ds:X509Data></ds:KeyInfo></ds:Signature>
>> >> >>   <saml:Subject>
>> >> >>     <saml:NameID
>> >> >>
>> >> >>
>> >> >>
>> Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">CN=Benjamin
>> >> >> Henne,OU=UniHannover,O=GermanGrid,C=DE</saml:NameID>
>> >> >>     <saml:SubjectConfirmation
>> >> >> Method="urn:oasis:names:tc:SAML:2.0:cm:holder-of-key">
>> >> >>       <saml:SubjectConfirmationData>
>> >> >>         <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
>> >> >>           <ds:X509Data>
>> >> >>             <ds:X509Certificate>...</ds:X509Certificate>
>> >> >>           </ds:X509Data>
>> >> >>         </ds:KeyInfo>
>> >> >>       </saml:SubjectConfirmationData>
>> >> >>     </saml:SubjectConfirmation>
>> >> >>   </saml:Subject>
>> >> >>   <saml:Conditions NotBefore="2008-10-16T19:03:57.920Z"
>> >> >> NotOnOrAfter="2008-10-17T06:03:57.920Z"/>
>> >> >>   <saml:AttributeStatement>
>> >> >>     <saml:Attribute Name="http://voms.forge.cnaf.infn.it/roles"
>> >> >>
>> NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">VO-Admin@/RVS</saml:AttributeValue>
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">resass@/RVS/education</saml:AttributeValue>
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">staff@/RVS/research/SAML</saml:AttributeValue>
>> >> >>     </saml:Attribute>
>> >> >>     <saml:Attribute Name="nationality"
>> >> >>
>> NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">German</saml:AttributeValue>
>> >> >>     </saml:Attribute>
>> >> >>     <saml:Attribute Name="http://voms.forge.cnaf.infn.it/group"
>> >> >>
>> NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">/RVS/education</saml:AttributeValue>
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">/RVS</saml:AttributeValue>
>> >> >>       <saml:AttributeValue
>> >> >> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> >> >> xsi:type="xs:string">/RVS/research</saml:AttributeValue>
>> >> >>     </saml:Attribute>
>> >> >>   </saml:AttributeStatement>
>> >> >>  </saml:Assertion>
>> >> >> </Response>
>> >> >
>> >> >
>> >
>> >
>>
>
>
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