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Overview

Dynamic Privilege Management Infrastructures Utilising Secure Attribute Exchange Dr John Watt Grid Developer, National e-Science Centre University of Glasgow jwatt@dcs.gla.ac.uk. Overview. DyVOSE Overview PERMIS Static PMI Implementation Shibboleth and the SAAM Module Dynamic Delegation

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Overview

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  1. Dynamic Privilege Management Infrastructures Utilising Secure Attribute ExchangeDr John WattGrid Developer, National e-Science CentreUniversity of Glasgowjwatt@dcs.gla.ac.uk

  2. Overview • DyVOSE Overview • PERMIS • Static PMI Implementation • Shibboleth and the SAAM Module • Dynamic Delegation • Future Work

  3. DyVOSE Overview • Dynamic Virtual Organisations for e-Science Education (DyVOSE) project • Two year project started 1st May 2004 funded by JISC • Exploring advanced authorisation infrastructures for security in context of education • University of Kent provide authorisation software (PERMIS) and security expertise • Applied in Grid Computing module part of advanced MSc at the University of Glasgow • Will provide insight into rolling out authorisation infrastructures/Grid to the masses • Exploration of current state of the art in authorisation infrastructures • Second phase of work involves NeSC Edinburgh • Extensions to the existing PERMIS infrastructure to provide dynamic delegation of authority and recognition of authority • Project website: http://www.nesc.ac.uk/hub/projects/dyvose/

  4. DyVOSE Participants • Dynamic Virtual Organisations in e-Science Education (DyVOSE) team • Principal Investigators • Dr Richard Sinnott (NeSC Glasgow) • Prof David Chadwick (Kent) • Implementation • Dr John Watt (NeSC Glasgow) • Dr Sassa Otenko (Kent) • Mr Tuan Anh Nguyen (Kent) • Mr Wensheng Xu (Kent) • Other Key People Involved • Dr David Berry (NeSC Edinburgh) • Dr Sandy Shaw (EDINA) – SDSS/Shibboleth

  5. DyVOSE Workplan Phase 1 • Looking at applying existing PERMIS technology to establish static Privilege Management Infrastructure at GU GU Condor pool ScotGrid Other (known!) Grid resources PERMIS based Education authorisation VO policies Authorisation checks Authorisation decisions

  6. DyVOSE Workplan Phase 2/3 Glasgow Edinburgh ScotGrid Condor pool Blue Dwarf Dynamically established VO resources/users Delegated VO policies Edinburgh Education VO policies Glasgow Education VO policies Shibboleth PERMIS based Authorisation checks/decisions

  7. Authorisation Technologies • CAS/VOMS • Rights/roles asserted by centralised server • No interpretation needed at resource end • Flexible at VO level, but no resource level decisions • Akenti • Access Control at Resource end (not central) • Desirable • Not VO specific • PERMIS • X509 and SAML

  8. PERMIS PrivilEge and Role Management Infrastructure Standards validation • X509 Role Based Access Control (RBAC) • Attribute Certificates hold user roles in LDAP • XML policy defines the access control • Java API allows any app to be protected • Complex Policies and multiple Attribute Authorities supported

  9. PERMIS Functionality • PERMIS allows to • Define roles for who can do what on what • Policy = { Role x Target x Action } • Can user X invoke service Y and access or change data Z? • Policies created with PERMIS PolicyEditor (output is XML file)

  10. PERMIS XML Policy

  11. PERMIS based Authorisation • PERMIS Privilege Allocator then used to associate roles with specific users • Signed policies are stored as attribute certificates in LDAP server • Exploiting the GGF AuthZ specification • Generic way to authorise access to Grid services using SAML callouts • Based on GT3.3 – PERMIS • Grid service (WSDD) has policy information associated with it • DN of clients, target and actions checked when attempts made to invoke services • “BRIDGES and DyVOSE only projects exploiting this API right now” (Von Welch at AHM 2004)

  12. Explorations in Grid Course • Students applied Policy Editor to develop security policy for use in their assignment • Sorting/searching “works of Shakespeare” • … run on single PC, • … using training lab Condor pool, • … * as GT3.3/Condor service, • … as GT3.3 service using GSI, • To see how authorisation at service level achieved • Service should be accessible by themselves and lecturing staff only • … using * for GT3.3-PERMIS authorised service • To see how authorisation at method level achieved • Students split into groups (Gp1, Gp2) • Sort method available to their group and lecturers only • Search method available to all • Performance aspects investigated throughout…

  13. PERMIS/Globus Issues • Long time wrestling with GT3.3-PERMIS integration • Some delays due to version issues with GT3.3 • Also required some debugging of GT3.3 (commenting out code) • Continued feedback on PERMIS tools • Policy editor refinements • Numerous discussions/meetings with Salford team on sorting out PERMIS-GT3.3 issues • Certificate dependencies in using PERMIS • Expects certificates created using openSSL • Experienced gained for DyVOSE Phase 2…

  14. SSO and Access Control on Web Resources • Home Institution AUTHENTICATES • Recognised across the federation • Temporary handle created • Releases user attributes to service providers • User can restrict attribute set release • Resource Institution AUTHORISES • Using attributes passed by the home institution • Resource has final access decision • Resource trusts Home to release correct info… • We have V1.2 operating as part of SDSS… • Walkthrough provided on DyVOSE website

  15. Messages are secure, attributes may not be! • Shibboleth encodes its messages in SAMLv1.1 • But attributes are not digitally signed (plaintext) • Authz Configuration is Apache-based • Any changes to rules requires complete restart of Web Server • Multiple Attribute Authorities unsupported • Coarse grained access control function • “User A with Attribute B can access C”

  16. …again! • Could PERMIS resolve these issues? • Attributes are stored in digitally signed X509 ACs • User attributes are now secure • PERMIS PMI controls the Authorisation • No Shibboleth/Apache restart when rules change • PERMIS supports multiple Sources of Authority • User may select attributes from more than one AA • Complex access control policies • Conditionals, Role Hierarchies

  17. The PERMIS SAAM Module • Apache module providing an authorisation handling function • mod_permis loaded BEFORE Shibboleth module in Apache configuration file httpd.conf • Requires alteration of approx 5 files at federation sites • mod_permis can either • Collect the ACs from LDAP itself (PULL mode) • Be provided the ACs for decision (PUSH mode) “Development of a Flexible PERMIS Authorisation Module for Shibboleth and Apache Server” D.Chadwick, O.Otenko, W.Xu

  18. The PERMIS SAAM Module

  19. Dynamic Delegation • Static PMI successfully built at Glasgow • Goal is to build a PMI-based VO between Glasgow and Edinburgh • Requires provision for Dynamic Delegation of Authority • Extensions to the PERMIS software will implement this infrastructure • Two cases will be investigated: • Static Delegation (easily done by adding Edinburgh SOA and Roles to Policy) • Simple Dynamic delegation (this year’s Grid Course…)

  20. Static Delegation

  21. Simple Dynamic Delegation

  22. Future Work • Implementation of new PERMIS Dynamic Delegation Software • DIS (Delegation Issuing Service) • Cross-certification • Role Mapping • Design of final student use-case to demonstrate dynamic PMI • Final Report on best practices and methods

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