O Shibboleth passa o atributo para a variável do servidor em PHP

Question

Estou construindo um mecanismo de autenticação federada baseado em SAML no qual o IdP é o ADFS 2.0 e o SP é o Shibboleth em execução no Linux. Eu posso fazer o seguinte:

1. Tentativa de acessar uma página protegida, o que me redireciona para a página de login do IdP.
2. Faça login por meio da página de login do IdP e retorne à página protegida.
3. Navegue até spserver.internal / Shibboleth.sso / Session e veja os atributos retornados, incluindo eppn.

No entanto, não consigo extrair o atributo eppn na forma do cabeçalho REMOTE_USER no PHP.

Desativei attribute-policy.xml (comentei em shibboleth2.xml).

Eu estou sentindo falta de algo trivial, eu suspeito que para o mundo de mim eu não sei o quê. Ou o PHP não está pegando as variáveis de servidor definidas pelo Shibboleth ou o Shibboleth nunca as configura. Alguma idéia?

Saída de spserver.internal / Shibboleth.sso / Session

Miscellaneous
Session Expiration (barring inactivity): 479 minute(s)
Client Address: a.b.c.d
SSO Protocol: urn:oasis:names:tc:SAML:2.0:protocol
Identity Provider: http://veragence.thesixthflag.com/adfs/services/trust
Authentication Time: 2014-10-28T11:55:23.947Z
Authentication Context Class: urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport
Authentication Context Decl: (none)

Attributes
eppn: [email protected]

Linha relevante de shibboleth2.xml:

    <ApplicationDefaults entityID="https://spURL/shibboleth"
                     REMOTE_USER="eppn persistent-id targeted-id">

Linha relevante de attribute-map.xml

<Attribute name="urn:oid:1.3.6.1.4.1.5923.1.1.1.6" id="eppn">
    <AttributeDecoder xsi:type="ScopedAttributeDecoder"/>
</Attribute>

Saída relevante do shibd.log

2014-10-28 11:55:21 DEBUG Shibboleth.SSO.SAML2 [2]: extracting issuer from SAML 2.0 assertion
2014-10-28 11:55:21 DEBUG OpenSAML.SecurityPolicyRule.MessageFlow [2]: evaluating message flow policy (replay checking on, expiration 60)
2014-10-28 11:55:21 DEBUG XMLTooling.StorageService [2]: inserted record (_06157709-48ab-4701-90b2-b3ecea5df51f) in context (MessageFlow) with expiration (1414497564)
2014-10-28 11:55:21 DEBUG OpenSAML.SecurityPolicyRule.XMLSigning [2]: validating signature profile
2014-10-28 11:55:21 DEBUG XMLTooling.TrustEngine.ExplicitKey [2]: attempting to validate signature with the peer's credentials
2014-10-28 11:55:21 DEBUG XMLTooling.TrustEngine.ExplicitKey [2]: signature validated with credential
2014-10-28 11:55:21 DEBUG OpenSAML.SecurityPolicyRule.XMLSigning [2]: signature verified against message issuer
2014-10-28 11:55:21 DEBUG OpenSAML.SecurityPolicyRule.BearerConfirmation [2]: assertion satisfied bearer confirmation requirements
2014-10-28 11:55:21 DEBUG Shibboleth.SSO.SAML2 [2]: SSO profile processing completed successfully
2014-10-28 11:55:21 DEBUG Shibboleth.SSO.SAML2 [2]: extracting pushed attributes...
2014-10-28 11:55:21 DEBUG Shibboleth.AttributeExtractor.XML [2]: unable to extract attributes, unknown XML object type: samlp:Response
2014-10-28 11:55:21 DEBUG Shibboleth.AttributeExtractor.XML [2]: unable to extract attributes, unknown XML object type: {urn:oasis:names:tc:SAML:2.0:assertion}AuthnStatement
2014-10-28 11:55:21 INFO Shibboleth.AttributeExtractor.XML [2]: skipping unmapped SAML 2.0 Attribute with Name: http://schemas.xmlsoap.org/ws/2005/05/identity/claims/upn, Format:urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified
2014-10-28 11:55:21 DEBUG Shibboleth.AttributeDecoder.Scoped [2]: decoding ScopedAttribute (eppn) from SAML 2 Attribute (urn:oid:1.3.6.1.4.1.5923.1.1.1.6) with 1 value(s)
2014-10-28 11:55:21 DEBUG Shibboleth.SSO.SAML2 [2]: resolving attributes...
2014-10-28 11:55:21 DEBUG Shibboleth.AttributeResolver.Query [2]: found AttributeStatement in input to new session, skipping query
2014-10-28 11:55:21 DEBUG Shibboleth.SessionCache [2]: creating new session
2014-10-28 11:55:21 DEBUG Shibboleth.SessionCache [2]: storing new session..