Common CE XACML Authorization Profile (v.0)

First draft for the common CE XACML authorization profile.

Introduction

References

[XACML]

OASIS Standard, eXtensible Access Control Markup Language, Version 2.0, February 2005. http://docs.oasis-open.org/xacml/2.0/access_control-xacml-2.0-core-spec-os.pdf

[XACML-CREAM]

XACML Profile for the gLite CREAM CE (Draft). https://edms.cern.ch/document/1078881/

[SAML-EMI]

EMI Common SAML Attributes. https://twiki.cern.ch/twiki/bin/view/EMI/EmiJra1T4SAML

[RFC2253]

http://www.ietf.org/rfc/rfc2253.txt

Notation

The examples use the following namespace prefixes:

The prefix ctx

stands for the XACML context namespace (urn:oasis:names:tc:xacml:2.0:context)

XML Namespaces

The XACML common CE profile syntax is defined in a schema associated with the following XML namespaces:

• http://dci-sec.org/xacml/attribute
• http://dci-sec.org/xacml/datatype
• http://dci-sec.org/xacml/algorithm
• http://dci-sec.org/xacml/action
• http://dci-sec.org/xacml/profile

Subject Attributes

Subject Identifier

Identify the submitter of the job to the CE. The attribute MUST be present in the request.

AttributeId

urn:oasis:names:tc:xacml:1.0:subject:subject-id

DataType

urn:oasis:names:tc:xacml:1.0:data-type:x500Name

AttributeValue Multiplicity

1

Value(s)

X.509 distinguished name of the end-entity certificate. The DN format is RFC2253, e.g. "CN=John Doe,DC=example,DC=org"

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”urn:oasis:names:tc:xacml:1.0:subject:subject-id” 
      DataType=”urn:oasis:names:tc:xacml:1.0:data-type:x500Name”>
    <ctx:AttributeValue>
      CN=John Doe,DC=example,DC=org
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Subject Issuer

DNs of the subject of all the root certificate authority and all subordinate certificate authorities within the certificate chain identifying the job submitter. The attribute SHOULD be present in the request.

For example, assume:

• certificate C is the end entity certificate
• subordinate certificate authority B signed certificate C
• root certificate authority A signed subordinate certificate authority B

AttributeId

http://dci-sec.org/xacml/attribute/subject-issuer

DataType

urn:oasis:names:tc:xacml:1.0:data-type:x500Name

AttributeValue Multiplicity

1..N

Value(s)

X.509 distinguished name of the authority(ies) which issued the job submitter's identity. The DN format is RFC2253.

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/subject-issuer” 
      DataType=”urn:oasis:names:tc:xacml:1.0:data-type:x500Name”>
    <ctx:AttributeValue>
      CN=QV Schweiz ICA,OU=Issuing Certificate Authority,O=QuoVadis Trustlink Schweiz AG,C=CH
    </ctx:AttributeValue>
    <ctx:AttributeValue>
      CN=QuoVadis Root Certification Authority,OU=Root Certification Authority,O=QuoVadis Limited,C=BM
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Virtual Organization (VO)

The subject's virtual organization membership.

TODO: add link to the common SAML profile

AttributeId

http://dci-sec.org/xacml/attribute/virtual-organization

DataType

http://www.w3.org/2001/XMLSchema#string

AttributeValue Multiplicity

1..N

Value(s)

Names of virtual organizations the subject is member of.

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/virtual-organization” 
      DataType=”http://www.w3.org/2001/XMLSchema#string”>
    <ctx:AttributeValue>
      atlas
    </ctx:AttributeValue>
    <ctx:AttributeValue>
      vo.example.org
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Comments

Aleksandr Konstantinov

Maybe accompanied by issuer - like VOMS SN.

Group Membership

The subject group membership.

TODO: add link to the common SAML profile.

AttributeId

http://dci-sec.org/xacml/attribute/group

DataType

http://dci-sec.org/xacml/datatype/group

AttributeValue Multiplicity

1..N

Value(s)

Names of the group the subject is member of.

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/group” 
      DataType=”http://dci-sec.org/xacml/datatype/group”>
    <ctx:AttributeValue>
      /atlas/admin
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Role

Represents the roles assigned to the subject. The subject role MUST be scoped to a particular group or VO name.

AttributeId

http://dci-sec.org/xacml/attribute/role

DataType

http://dci-sec.org/xacml/datatype/role

Issuer

Group name or VO name scope of the role.

AttributeValue Multiplicity

1..N

Value(s)

Names of the role assigned to the subject.

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/role” 
      DataType=”http://dci-sec.org/xacml/datatype/role”
      Issuer="/atlas/analysis">
    <ctx:AttributeValue>
      SoftwareManager
    </ctx:AttributeValue>
  </ctx:Attribute>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/role” 
      DataType=”http://dci-sec.org/xacml/datatype/role”
      Issuer="atlas">
    <ctx:AttributeValue>
      Tester
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Questions

• is an attribute uniquely identified by the {AttributeId, DataType, Issuer} tuple (see [XACML] 5.37 AttributeDesignatorType)?

Primary Membership

Represents the default membership attribute assigned to the subject. The membership is either a scoped role or a group.

AttributeId

http://dci-sec.org/xacml/attribute/primary

DataType

http://dci-sec.org/xacml/datatype/role or http://dci-sec.org/xacml/datatype/group

Issuer

If the primary membership is a scoped role, then it contains the role scope. Otherwise the Issuer is not set.

AttributeValue Multiplicity

1

Value(s)

Name of the primary role assigned to the subject, or name of the primary group the subject is member of.

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/primary”
     DataType=”http://dci-sec.org/xacml/datatype/role”
     Issuer="atlas">
    <ctx:AttributeValue>
      Tester
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Questions

• isn't it too complicate ?
• better to use 2 different attributes http://dci-sec.org/xacml/attribute/role/primary and http://dci-sec.org/xacml/attribute/group/primary ?

Comments

Aleksandr Konstantinov

maybe add VO to Role and Group.

Resource Owner

AttributeId

http://dci-sec.org/xacml/attribute/resource-owner

DataType

urn:oasis:names:tc:xacml:1.0:data-type:x500Name

AttributeValue Multiplicity

1

Value(s)

X.509 distinguished name of the end-entity certificate.

Example

<ctx:Subject>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/resource-owner” 
      DataType=”urn:oasis:names:tc:xacml:1.0:data-type:x500Name”>
    <ctx:AttributeValue>
      CN=Jane Doe,DC=example,DC=org
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Subject>

Comments

• This attribute is required by UNICORE

Resource Attributes

Resource Identifier

Identifies the CE, or a logical grouping of CEs, upon which the action to be authorized will be executed. This attribute MUST be present in a request.

Identifier

urn:oasis:names:tc:xacml:1.0:resource:resource-id

DataType

http://www.w3.org/2001/XMLSchema#string

AttributeValue Multiplicity

1

Value(s)

???

Example

<ctx:Resource>
  <ctx:Attribute AttributeId=”urn:oasis:names:tc:xacml:1.0:resource:resource-id”
     DataType=”http://www.w3.org/2001/XMLSchema#string”>
    <ctx:AttributeValue>
      http://example.org/ce/cream-ce-1
    </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Resource>

Questions

• Is the DataType ...#string correct to identity a resource, why not ...#anyURI ?
• Should we formalize the resource identifier values ?

Comments

Karsten Schwank

I think it is a good idea to formalize the the values, otherwise I could imagine the risk of duplicates within a large system is too big and formalized values would keep the policies human readable. Depending on the kind of formalization this could even allow further automatic, semantic evaluation of the policies. Same thing for the actions.

Krzysztof Benedyczak

I vote for URI. In our case {UNICORE} it is an URL of the Web Service.

Aleksandr Konstantinov

too generic. Or it needs an attribute/scoping to define which kind of identifier it is - URL, SN, WS-Addressing, path. Also it is not clear to me how to specify resource at service which can't be represented as combined URL. Like job handled by Execution Service - with job id XML-ized and ES represented by URL or EPR.

Action Attributes

Action Identifier

Identifies the action being performed on the CE. This attribute MUST be present in a request.

Identifier

urn:oasis:names:tc:xacml:1.0:action:action-id

DataType

http://www.w3.org/2001/XMLSchema#string

AttributeValue Multiplicity

1

Value(s)

???

TODO:

• define the list of action value

Questions

• values multiplicity: 1 or 1..N ?

Comments

Krzysztof Benedyczak

My remark is that here (in opposite what is in the current CREAM profile) we want any string - without any restrictions. However we may obey some predefined actions if those are applicable.

Aleksandr Konstantinov

probably needs some scoping to define kind of service involved. Or there need to be some rules how to compose the string representing action which would allow to distinguish "create" action of Storage from "create" of ES.

Environment Attributes

Profile Identifier

Identify the profile implemented by the request sender. The attribute MUST be present in the request.

AttributeId

http://dci-sec.org/xacml/attribute/profile-id

DataType

http://www.w3.org/2001/XMLSchema#anyURI

AttributeValue Multiplicity

1

Value(s)

The attribute value MUST be http://dci-sec.org/xacml/profile/common-ce/1.0

Example

<ctx:Environment>
  <ctx:Attribute AttributeId=”http://dci-sec.org/xacml/attribute/profile-id” 
      DataType=”http://www.w3.org/2001/XMLSchema#anyURI”>
     <ctx:AttributeValue>
       http://dci-sec.org/xacml/profile/common-ce/1.0
     </ctx:AttributeValue>
  </ctx:Attribute>
</ctx:Environment>

Data-types

Defines the DataType s used in the XACML attributes.

Group DataType

Identifier

http://dci-sec.org/xacml/datatype/group

TODO: add description and link to the common SAML profile

Role DataType

Identifier

http://dci-sec.org/xacml/datatype/role

TODO: add description and link to the common SAML profile

FQAN DataType

Identifier

http://dci-sec.org/xacml/datatype/fqan

TODO: add description and link to the common SAML profile

Question

• is the FQAN still needed ???