DataGrid is a project funded by the European Union EDG Conference Barcelona 2003 – Title – n° 1 VOMS and LCMAPS on Global Permissions and Local Credentials David Groep & Gridification Team partly based on CHEP2003 talk by Luca dell’Agnello et al. (SCG, WP4, WP6)

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 2 Outline u Introduction u Authorization requirements u VO Membership Service u Local site enforcement mechanisms (LCAS, LCMAPS) n LCMAPS architecture n Evolution Manager and the Policy Language n Credential Enforcement Gotchas u Creating the highest CE density on the planet…

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 3 Introduction (1) u EDG security infrastructure based on X.509 certificates (PKI) u Authentication n 16 national certification authorities n Policies and procedures  mutual thrust n Users identified by certificates signed by their national CA u Authorization n Cannot decide Authorization for grid users only on local site basis n At least 2 entities involved s Resource Providers (e.g. Tiers in LCG framework) s Virtual Organizations (e.g. LHC experiments collaborations)

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 4 Introduction (2) u Authorization (cont.) n Resource granting established by agreements VO’s - RP’s. s VO’s administer user membership, roles and capabilities s RP’s evaluate authorization granted by VO to a user and map into local credentials to access resources n Need tool to manage membership for large VO’s (10000 users) s Globus mechanism (grid-mapfile) not scalable n VO membership service (VOMS) s Extends existing grid security infrastructure architecture with embedded VO affiliation assertions s Permits authorization control on grid services for job submission, file and database access.

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 5 Authorization requirements u Architecture n centralized and scalable (for an Auth policy VO based) u Attributes support n group membership (subgroup, multiple inheritance,..) n Roles (admin, student,..), capabilities (free form string),.. n Temporal bounds u Resource Provider n keep full control on access rights n traceability user level (not VO level) u Security issues n Auth Server must not be a Single point of failure n Auth communications must be trusted, secured and reserved

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 6 Globus Authorization Mechanism u grid-mapfile n Grid credentials (user’s Certificate) to local credentials (unix account) mapping n “Boolean” authorization n Information provided via VO-LDAP servers n Managed “manually” by the resource admin (via mkgridmap) u No centralization u No scalability u Lack of flexibility "/C=IT/O=INFN/L=Parma/CN=Roberto alfieri "/C=IT/O=INFN/L=Parma/CN=Fabio spataro

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 7 The Virtual Organization Membership Service u The Virtual Organization Membership Service (VOMS) n Developed by European Datagrid and Datatag collaborations to solve current LDAP VO servers limitations n Grants authorization data to users at VO level s Each VO has its own VOMS s Support for group membership (subgroup, multiple inheritance,..), “forced” groups (i.e. for negative permissions), roles (admin, student,..) and capabilities (free form string) n Essentially a front-end to an RDBMS s User client – queries the server for authorization info s User server – returns authorization info to the client s administration client – used by VO administrators for management s administration server – executes client update operations on db s transition tool – interface to mkgridmap++ (see below) n All client-server communications are secured and authenticated n Authorization info is processed by the gatekeeper s full functionality of VOMS achieved via LCAS/LCMAPS plug-ins (see below)

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 8 VOMS overview soap DB JDBC GSI https Tomcat & java-sec axis VOMS impl servlet vomsd Perl CLI Java GUI browser voms-proxy-init mkgridmap Apache & mod_ssl voms-httpd DBI http

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 9 VOMS Operations Query Authentication Request Auth DB C=IT/O=INFN /L=CNAF /CN=Pinco Palla /CN=proxy VOMS pseudo- cert 1. Mutual authentication Client-Server n Secure communication channel via standard Globus API 2. Client sends request to Server 3. Server checks correctness of request 4. Server sends back the required info (signed by itself) in a “Pseudo-Certificate” 5. Client checks the validity of the info received 6. Client repeats process for other VOMS’s 7. Client creates proxy certificates containing all the info received into a (non critical) extension 8. Client may add user-supplied auth. info (kerberos tickets, etc…)

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 10 Pseudo-Certificate Format /C=IT/O=INFN/L=CNAF/CN=Vincenzo /C= IT/O=INFN/CN=INFN CA /C=IT/O=INFN/OU=gatekeeper/L=PR /C=IT/O=INFN/CN=INFN CA VO: CMS URI: TIME1: Z TIME2: Z GROUP: montecarlo ROLE: administrator CAP: “100 GB disk” SIGNATURE: L...B]....3H =".h.r...;C'..S......o.g.=.n8S'x..\..A~.t 'Q.V.I..../.Z*V*{.e.RP.....X.r qEbb...A... u The pseudo-cert is inserted in a non- critical extension of the user’s proxy n u It will become an Attribute Certificate u One for each VOMS Server contacted user’s identity server identity user’s info

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 11 Authorization User VOMSservice authr map pre-proc authr LCAS LCMAPS pre-proc LCAS Coarse-grained e.g. Spitfire service dn dn + attrs Fine-grained e.g. RepMeC Coarse-grained e.g. CE, Gatekeeper Fine-grained e.g. SE, /grid Java C authenticate ACL

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 12 Local Site Authorization Services u Local Centre Authorization Service (LCAS) n Handles authorization requests to local fabric s Authorization decisions based on proxy user certificate and job specification s Supports grid-mapfile mechanism n Plug-in framework (hooks for external authorization plug-ins) s Allowed users (grid-mapfile or allowed_users.db) s Banned users (ban_users.db) s Available timeslots (timeslots.db) s Plugin for VOMS (to process Authorization data) u Local Credential Mapping Service (LCMAPS) n Provides local credentials needed for jobs in fabric n Plug-in framework, driven by comprehensive policy language n Mapping based on user identity, VO affiliation, site-local policy n Supports standard UNIX credentials (incl. pool accounts), AFS tokens, Krb5

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 13 EDG Gatekeeper (release 2.1) Gatekeeper LCAS allowed timeslot banned policy C=IT/O=INFN /L=CNAF /CN=Pinco Palla /CN=proxy VOMS pseudo- cert Job Manager fork+exec args, submit script LCMAPS open, learn, &run: … and return legacy uid LCAS authZ call out GSI AuthN accept TLS auth assist_gridmap Jobmanager-* Ye Olde Gatekeeper

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 14 Running a gatekeeper u Every “woody” is a CE u configuration in /etc/globus.conf u everything set up, except for grid-mapfile, LCMAPS and LCAS u start with “service globus-gatekeeper start” as root

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 15 LCMAPS – requirements u Backward compatible with existing systems (grid-mapfile, k5cert) u Support for multiple VOs per user (and thus multiple UNIX groups) u Mimimum system administration n Poolaccounts n Pool”groups” n Understandable configuration u Extendible u Boundary conditions n Has to run in privileged mode n Has to run in process space of incoming connection (for fork jobs)

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 16 LCMAPS – control flow u User authenticates using (VOMS) proxy u LCMAPS library invoked n Acquire all relevant credentials n Enforce “external” credentials n Enforce credentials on current process tree at the end u Run job manager n Fork will be OK by default n Batch systems may need primary group explicitly n Batch systems will need updated (distributed) UNIX account info u Order and function: policy-based CREDs LCMAPS Credential Acquisition & Enforcement Job Mngr GK

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 17 LCMAPS – plugin introspect u Framework is “resistent” to new module functionality and v.v. u Invocation and arguments list for modules discovered via the ”introspection API” n Information in (VOMS) proxy cert access by symbolic names n Argument description by name, type, range, modifiability n Credential acquisition in named and typed lists u Various modules can support different interfaces u Modules from multiple generation can be “mixed” u An “old” framework will work with “bleeding-edge” modules u See apidoc for more details…

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 18 LCMAPS – modules u Modules represent atomic functionality u VOMS from role info and local mapfile assign gid (A) u PoolAccounts from username assign unique uid (A) u PoolGroups from (VOMS) groupname assign unique gid (A) u LocalAccount from username assign local existing unique uid (A) u AFS/Krb5 get token based on user DN info (A) u POSIX process setuid() and setegid() (E) u POSIX LDAP update distributed user database (E) u Krb5 run job via k5cert (E) u …

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 19 LCMAPS – policy evaluation u State machine approach (superset of boolean expressions) u Policy description file: VOMS-group LocalAccount PoolAccount LDAPPOSIX FALSE TRUE path = /opt/edg/lib/lcmaps/modules localaccount ="lcmaps_localaccount.mod \ -gridmapfile /etc/grid-security/grid-mapfile" poolaccount = "lcmaps_poolaccount.mod -gridmapfile /etc/grid-security/grid-mapfile" posix_enf = "lcmaps_posix.mod -maxuid 1 -maxpgid 1 -maxsgid 32" voms = "lcmaps_voms.mod -vomsdir /etc/grid-security/certificates \ -certdir /etc/grid-security/certificates" standard: voms -> poolaccount | localaccount localaccount -> posix_enf poolaccount -> ldap ldap -> posix_enf

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 20 LCMAPS – invocation and running LCMAPSPlugin MngrEvolution Mngrany Plug-in Local init Read and evaluate policy Load all Initialise all Introspect for API terminations from GK

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 21 LCMAPS – enabling new functionality u Local UNIX groups based on VOMS group membership and roles u More than one VO/group per grid user u No pre-allocation of pool accounts to specific groups u New mechanisms: n groups-on-demand n Central user directories (nss_LDAP, pam-ldap) u Why do we (still) need LCAS: n Centralized decisions on authorized users (like at FNAL) n Coordinated access control across multiple CEs n (and save on expensive account allocation mechanisms in LCMAPS)

WP4 meeting EDG Barcelona 2003 – VOMS and LCMAPS – n° 22 More Informations EDG Security Coordination Group Web site VOMS Web site CVS site Developers’ mailing list LCAS-LCMAPS Web site CVS site Maillist