OASIS eXtensible Access Control Markup Language (XACML) TC

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Re: [xacml] Potential SAML issues

  • 1.  Re: [xacml] Potential SAML issues

    Posted 01-15-2002 03:57
    Hello,
    
    Sekhar Vajjhala - Sun Microsystems wrote:
    > ISSUE: saml:Action is a "string"
    > 
    >      saml:Action is currently specified as a "string". Making Action
    >      an abstract type  would allow it to be extended. This would allow
    >      the content model to be defined by a schema external to the SAML
    >      spec.
    >  
    >      Thus what constitues an action could be determined by the J2SE
    > schema.
    
    In SAML, saml:Action is used only in saml:Actions and saml:Actions
    have Namespace as an attribute.
    So it is possible to write action(s) such as:
      <saml:Actions Namespace="urn:J2SEPermission:java.io.FilePermission">
        <saml:Action>write</saml:Action>
      </saml:Actions>
    or
      <saml:Actions Namespace="urn:J2SEPermission">
        <saml:Action>java.io.FilePermission:write</saml:Action>
      </saml:Actions>
    
    But it will be useful if we can write something like:
      <saml:Action>
        <J2SEPermission class="java.io.FilePermission">write</J2SEPermission>
      </saml:Action>
    
    
    > ISSUE: saml:AuthorizationQuery requires actions.
    > 
    >      If actions are optional for XACML, then why should <saml:Actions>
    >      be required in <saml:AuthorizationQuery> ? Both the wording in
    >      the SAML assertions draft as well as the SAML schema place
    >      such a requirement. saml:Actions should be optional in the
    >      AuthorizationQuery to accomodate queries without actions.
    > 
    >      At least for now, I don't anticipate this as an issue for J2SE.
    
    In the latest SAML spec (core-25), AuthorizationDecisionQuery element
    has Resource attribute and Actions element and both of them are
    "required". Does this cause much problems?
    (Resource attribute is "optional" for AuthorizationDecisionStatement
    element.)
    
    As for J2SE case, I think there is an issue in terminology.
    Sekhar wrote::
    |     A J2SE permission consists of 
    | 
    |     a. target   ("resource" in XACML terminology )
    |     b. action   (optional)
    (http://lists.oasis-open.org/archives/xacml/200112/msg00045.html)
    
    In the example of FilePermission, everyone will agreee on that
    "/tmp/*" indicates resources(targets) and "read,write" indicates
    action(s).
    
    In regard to AWTPermission, the J2SE document says:
    | This is in the same spirit as the RuntimePermission; it's a
    | permission without actions. The targets for this class are:
    | 
    | accessClipboard
    | accessEventQueue
    | listenToAllAWTEvents
    | showWindowWithoutWarningBanner
    (http://java.sun.com/j2se/1.4/docs/guide/security/spec/security-spec.doc3.html#20327)
    
    It says that "accessClipboard" is a target, however, I think it is
    possible to say "accessClipboard" is an action (in XACML terminology).
    
    
    > ISSUE: single subject in AuthorizationQuery
    > 
    >      saml:AuthorizationQuery currently only contains a single
    >      Subject. While a saml:Subject can support multiple NameIdentifier
    >      or SubjectConfirmation or AssertionSpecifier elements, it
    >      is required that they all belong to the same principal. So
    >      a single subject cannot be used for unrelated principals.
    > 
    >      In J2SE, there is a need to base access control on multiple
    >      principals which are not related and this therefore points to
    >      to a need for more than one Subject in the saml:AuthorizationQuery
    > 
    >      NOTE: The way out of this appears to be extend
    > SubjectQueryAbstractType.
    
    Is this the same issue with ISSUE:[DS-11-01:MultipleSubjectAssertions]
    in draft-sstc-saml-issues-06.pdf?
    
    Regards,
    Toshi
    ---
    NISHIMURA Toshihiro (FAMILY Given)
    nishimura.toshi@jp.fujitsu.com
    XML Application Technology Dept., PROJECT-A XML, FUJITSU LIMITED