Topics in Directories: Groups Dr. Tom Barton The University of Memphis

25 June 2002Base CAMP2 Outline What is it for? Design factors – how to approach the design of a groups implementation Examples & vignettes Group management issues Vaporware References

25 June 2002Base CAMP3 Why do groups? Leverage existing enterprise directory infrastructure to: Supply data for access control policies to directory integrated applications and service platforms. Supply data for customization needs, especially CMSs and portals. Facilitate group messaging. Facilitate automated IT resource provisioning.

25 June 2002Base CAMP4 Design factors for a groups implementation How the group information is to be most commonly accessed. How the group information is to be maintained. How potential interactions arise between: the type of group representation the nature of the group (eg, size or privacy requirements) capabilities of the particular directory service agent being used

25 June 2002Base CAMP5 Design factors: Representations of groups Static: group object with multivalued membership attribute. groupOfNames groupOfUniqueNames dn: cn=groupA, ou=groups, dc=some, dc=edu objectclass: groupOfUniqueNames cn: groupA uniquemember: uid=user1,ou=people,dc=some,dc=edu uniquemember: uid=user2,ou=people,dc=some,dc=edu uniquemember: uid=user3,ou=people,dc=some,dc=edu

25 June 2002Base CAMP6 Design factors: Representations of groups Dynamic: membership determined by executing an ldap url groupOfURLs (iPlanet proprietary) No group object – ldap url exists only in applications using it. dn: cn=groupB, ou=groups, dc=some, dc=edu objectclass: groupOfURLs cn: groupB memberURL: ldap://ldap.some.edu389/ou=people, dc=some,dc=edu?dn?2?(ou=staff)

25 June 2002Base CAMP7 Design factors: Representations of groups Forward reference: multivalued attribute (isMemberOf) in an object lists its memberships. dn: uid=user1, ou=people, dc=some, dc=edu objectclass: someEduPerson cn: Some Body sn: Body uid: user1 isMemberOf: groupA isMemberOf: groupB

25 June 2002Base CAMP8 Design factors: Representations of groups Spatial: membership is inferred from object’s location in the DIT.

25 June 2002Base CAMP9 Design factors: Application access questions How will applications query for group information? Is object X in group A? List all members of group A. List all groups to which X belongs. List all members of some boolean combination of groups. List all members of group A meeting specified additional criteria.

25 June 2002Base CAMP10 Design factors: Application access questions Are there application restrictions on: group names static group objectclass selection ability to use object attributes (dynamic groups) where in the DIT to look for group objects Are there application constraints impacting access policy? Can application BIND as a given user (aka serviceDN), enabling directory ACLs to accurately implement institutional access policy?

25 June 2002Base CAMP11 Design factors: Group maintenance questions Will membership info be automatically maintained based upon institutional data? Will membership info be manually maintained? How will delegation of group update priviledges be managed? Is it a personal group? What institutional policy pertains to the visibility of the group or privacy of its membership information?

25 June 2002Base CAMP12 Design factors: Group maintenance questions Both automatic and manual processes update the same group? Need a group maintenance application. Is there a need to hide personal groups from certain enterprise applications? Limited expressiveness of directory ACLs might limit ability to delegate maintenance of member object attributes without use of an intervening group maintenance application.

25 June 2002Base CAMP13 Design factors: DSA interactions Size limit for static groups? Replication performance for large static groups. Processor and return size limits vs. listing membership of large dynamic groups. Access control language vs. delegated maintenance of dynamic (or forward reference) groups.

25 June 2002Base CAMP14 Core middleware for an integrated architecture

25 June 2002Base CAMP15 Example: Class website Students & instructor(s) use a course website to support class activities. The website provides views only to those resources associated with the role they have in each class. class: ENGL U instructor: uid=user1, … student: uid=user2, … student: uid=user3, … class: COMP U instructor: uid=user4, … student: uid=user5, … student: uid=user6, … SIS Metadirectory MyClass

25 June 2002Base CAMP16 Example: Data Warehouse Access GUI web reporting tool (BRIO) for DW access has native LDAP authentication, but groups used for application security are stored in the DW. Application level security priviledges are determined by combination of DW administrators and business office personnel. owner: uid=DWadmin,… uniquemember: uid=user1, … uniquemember: uid=user2, … owner: uid=BOadmin,… uniquemember: uid=user3, … uniquemember: uid=user4, … DW GASP Duper BRIO

25 June 2002Base CAMP17 Student vignette Mary is a grad student at Alpha U, taking courses both in a traditional classroom and online and interns at a biotech company nearby. Using her laptop, Mary needs to access her , courseware, calendar and library resources from all three locations; home, campus and work. She also uses a wireless PDA when on- campus to stay in touch with her lab mates. Mailbox Calendar Wireless Gateway NAS Server Lib Proxies CMS authN attrs

25 June 2002Base CAMP18 Provisioning vignette The new Chair of the Dept. of Physiology has arrived on campus over the weekend. Dr. Agnew is very anxious to get access to campus IT resources such as , calendar, web services and the mainframe. He does not want to wait for the requisite 3-5 business days it takes to get the accounts setup. Since IT already knows of him, he can use a self-service interface to accomplish his goal. HRS Metadirectory Acct Init Service authN attrs

25 June 2002Base CAMP19 Group management issues Maintenance & indexing of membership attributes Delegating management Referential integrity Personal groups Privacy & visibility Group math Forward referencing Aging Namespace issues

25 June 2002Base CAMP20 Vapor groupware GASP (Group Authorized Service Process). Utility that provides group create, rename, update, delete capabilities within an access controlled environment. Grouper. Extension to DSA presenting group math capabilites to ldap clients. RIbot. Referential Integrity maintenance utility. Maintains integrity of forward references too.

25 June 2002Base CAMP21 References Practices in Directory Groups – Tom Barton LDAP Recipe 2.0 – Michael Gettes (forthcoming) Groups Implementation Guide – Eileen Shepard