Monday, February 28, 2011

Going through the Argus Valley

Being an early adopter site for Argus, Oxford got one of the first MUPJ from ATLAS using glexec through Argus and it failed! although we were passing ops glexec tests for long.
Our understanding of Argus was that it must have a policy which authorize pilots to switch to a normal user, so I had a policy like this to authorize pilot for glexec

resource "" {
obligation "" {

action "" {
rule permit { pfqan="/ops/Role=pilot" }
rule permit { pfqan="/atlas/Role=pilot" }
rule permit { pfqan="/cms/Role=pilot" }

After discussion with Argus experts on mailing list, it turned out that when pilot framework ask glexec to switch user from pilot to the effective user, LCMAP PEP plugin send the proxy of effective user to ARGUS server for authorization and mapping. So Argus must have policy which authorize effective user also. I have changed policy to look like that

rule permit {pfqan = "/atlas/Role=pilot" }
rule permit {pfqan = "/atlas/Role=lcgadmin" }
rule permit {pfqan = "/atlas/Role=production" }
rule permit {pfqan = "/atlas/" }

It solved the problem. Doesn't it look like that every atlas user is allowed to switch identity through glexec ? As for as Argus is concerned, yes. But glexec configuration is defined at WN and only groups which are whitelisted at /opt/glite/etc/glexec.conf are allowed to use glexec, any other user trying glexec will be shot down at WN itself. By default only pilot users are whitelisted at WN.
So in nutshell, policies at Argus should resemble that of the CE.