tom barton 1 , jim basney 2 , tim freeman 1 , tom scavo 2 ,

Identity Federation and Attribute-based Authorization

through the Globus Toolkit, Shibboleth, GridShib, and MyProxy

Tom Barton1, Jim Basney2, Tim Freeman1, Tom Scavo2,Frank Siebenlist1,3, Von Welch2, Rachana Ananthakrishnan3,

Bill Baker2, Monte Goode4, Kate Keahey1,3

1University of Chicago 2National Center for Supercomputing Applications, University of Illinois

3Mathematics and Computer Science Division, Argonne National Laboratory4Lawrence Berkeley National Laboratory

NIST PKI Workshop, April 4th 2006

Background

3NIST PKI Workshop April 4, 2006

Globus Toolkit• http://www.globus.org• Toolkit for Grid computing

– Job submission, data movement, data management, resource management

• Based on Web Services and WSRF• Security based on X.509 identity- and

proxy-certificates– May be from conventional or on-line CAs


Grid PKI• Large investment in PKI at the international level

for Grids– Dozens of CAs, thousands of users

• International Grid Trust Federation– http://www.gridpma.org

• Intended for point-in-time authentication– As opposed to, e.g., document signing

• Uses RFC 3820 Proxy Certificates for delegation and single-sign on

• Keys stored in Highest Common Technology == User’s local filesystem

http://www.gridpma.org/


Shibboleth• Internet2 project• Standards-based (SAML)• Allows for Identity Federation

– Identity == Identifier + Attributes– Identifier may or may not be a persistent Name.– Allows for pseudonymity via temporary, meaningless

identifiers called ‘Handles’

• Allows for inter-institutional sharing of web resources (via browsers)– Provides attributes for authorization between institutions

• Being extended to non-web resources


MyProxy• The Team:

– Jim Basney (lead), Bill Baker, Patrick Duda, Von Welch• Many contributors

– E.g. Monte Hall (LBNL)• A service for managing X.509 PKI credentials

– A credential repository– Long-lived private keys never leave the server

• Originally, a method for delegating credentials to Web Portals– Work around for lack of delegation in Web Browsers– User delegates RFC 3820 Proxy Certificate to MyProxy,

Portal delegates from MyProxy• Open Source Software

– Included in Globus Toolkit 4.0 and CoG Kits– C, Java, Python, and Perl clients available


GridShib• NSF NMI project to allow the use of Shibboleth-issued

attributes for authorization in NMI Grids built on the Globus Toolkit– Funded under NSF NMI program

• GridShib team: NCSA, U. Chicago, ANL– Tom Barton, Tim Freemon, Kate Keahey, Raj Kettimuthu, Tom

Scavo, Frank Siebenlist, Von Welch

• Working in collaboration with the Internet2 Shibboleth Design team


Common Goals of GridShib and MyProxy

• Ease of use for Grid PKIs• X509 Credential management is a big

headache for all involved– Users hate process of getting certificates– Admins hate not know where private keys are– Everyone hates configuration overhead (mainly

CRLs)• Both projects working to use federation

combined with X509 to solve these problems• Integration of Site with Grid security

Results from Past Year


MyProxy Authentication• MyProxy has traditionally supported:

– Key Passphrase– X.509 Certificate for credential renewal

• In the past year, we have added:• Pluggable Authentication Modules (PAM)

– Kerberos password– One Time Password (OTP)– Lightweight Directory Access Protocol (LDAP) password

• Simple Authentication and Security Layer (SASL)– Kerberos ticket (SASL GSSAPI)

• PubCookie


MyProxy Online Certificate Authority• Issues short-lived X.509 End Entity Certificates

– Leverages MyProxy authentication mechanisms– Compatible with existing MyProxy clients

• Ties in to site authentication and account management– Using PAM and/or Kerberos authentication– “Gridmap” file maps username to certificate subject

• LDAP support for mapping• Avoid need for long-lived user keys• Server can function as both CA and repository

– Issues certificate if no credentials for user are stored• When combined with pluggable authentication, allows for easy

way to leverage existing authentication for X509 access– Kx509/KCA replacing Kerberos with various technologies

• (Implemented by Monte Goode @ LBNL)


MyProxy: Managing Trust Roots• Based on ideas put forth in Gutmann’s

plug-and-play PKI paper• When user authenticates to get X509

credential, also provide needed trust information– CA certificates, CRLS, other related policy


GridShib Overview• Two components

– GridShib handlers for Globus Toolkit (GT4)– GridShib plugin for Shibboleth (1.3)

• Working together they allow GT service to request Shibboleth attributes

• And make authz decision based on those attributes

• All software open source


GridShib for Globus Plugin• Three components• Basic SAML Query Policy Information

Provider (PIP)– Queries Shibboleth AA using X509 DN and

retrieves user attributes– Needs GridShib for Shibboleth plugin at AA

• SAML identity mapper PIP determines local username from SAML attributes

• SAML PDP makes access control decision based on SAML attributes


GT Authorization Architecture• GridShib work is forming basis for rich authorization

architecture in GT• Configurable collection of PIPs gather attributes

regarding user– SAML, X509, local, etc.– Canonicalize to XACML Request Context

• Configurable collection of PDPs render authorization decision– PDPs can be local or remote (GGF OGSA-Authz SAML

protocol)– PDPs can be combined logically in different ways (AND or

OR)– PDPs can gather own attributes (e.g. PERMIS)


GridShib for Shibboleth Plugin• NameMapper for Shibboleth IdP• Converts X509 DN into locally

meaningful name• Currently uses static mapping

– Already being improved on


GridShib Flow: Putting it together• User makes request of GT service as usual

– X509 authentication with SOAP• GT SAML PIP queries Shibboleth AA using DN

– SAML Query protocol• GridShib Namemapper converts from DN to local

principal name• Shibboleth AA returns SAML assertion with attributes

– SAML Response protocol• GT SAML PIP binds attributes to DN in GT internal

state• GT then maps user to local account and/or renders

access control decision

Next Steps


GridShib/MyProxy Integration• Allow for leveraging of Shibboleth SSO for Grids

– Need to convert Shibboleth SAML into X509• Accomplish by adding SAML authentication support

to MyProxy– Ala Pubcookie

• Have implemented prototype GridShib CA– Portal authenticates user, MyProxy trusts portal to have

done so and issues X509 Credential– Java Web Start application download credential from portal

to user desktop• Investigating full Shibboleth authentication to

MyProxy– May have to wait until Shibboleth 2.x


The Name Mapping Problem

• End-to-end flow involves both protocol and name conversion– Site, SAML, X509

• Not clear that these conversions should be co-located, who should be authoritative


Name Binding• If site is authority for both SAML and X509 names, then they can

make mappings or use algorithmic transformation• Today this is often not the case

– E.g. CA is run by Grid community• Two options we’re exploring:• User binds names by dual-authentication• CA binds names when it issues a credential

– Either by direct communication with Shibboleth AA• Allow Shibboleth AA to recognize DN

– Or by embedding information into the X509 certificate• Allows resource to know Shibboleth Name

• Working in collaboration with Jill Gemmill, J.P. Robinson @ UAB (myVocs)


Questions?• [email protected]• Project URLS

– http://gridshib.globus.org– http://myproxy.ncsa.uiuc.edu– http://shibboleth.internet2.edu/

• Acknowledgements– The GridShib work is funded by the NSF National Middleware

Initiative (NMI awards 0438424 and 0438385). Opinions and recommendations in this paper are those of the authors and do not necessarily reflect the views of NSF.

– The MyProxy work was funded by the NSF NMI Grids Center and the NCSA NSF Core awards. The online CA work was implemented at LBNL.





tom barton 1 , jim basney 2 , tim freeman 1 , tom scavo 2 ,

Documents

backgroundnist pki workshop

grid securitynist pki

past yearnist pki workshop

online casnist pki workshop

web portalswork

web services

use of shibboleth

web browsersuser delegates