[SSSD-users] idmaping, nfs4krb, AD multi domain forest

Jakub Hrozek jhrozek at redhat.com
Mon Jan 19 20:50:34 UTC 2015


On Fri, Jan 16, 2015 at 02:34:19PM +0000, Longina Przybyszewska wrote:
> 
> Hi,
> We have problems with authorization to the nfs mounted share with sec=krb5 in multi domain AD forest environment.
> 
> When server, client and user are from the same native domain, user’s  login,nfs+krb mount and access to nfs mounted share works fine.
> server at nat.c.example.com
> client at nat.c.example.com
> user-n at nat.c.example.com
> 
> When user is from another domain, login(via ssh, GUI) and  nfs+krb mount works; User gets ‘Permission denied ‘ to the nfsshare for rw
> server at nat.c.example.com
> client at nat.c.example.com
> user-a at adm.c.example.com
> 
> AD user test accounts (user-n, user-a) have Posix attributes ;
>  AD groups for Posix enabled users have Posix gids;
> 
> Test users are members  of universal group usr-sdu-glu at c.example.com;
> 
> SSSD is configured identically on client and server:
> 
> 
> [sssd]
> domains = nat.c.example.com
> config_file_version = 2
> services = nss, pam
> 
> [pam]
> pam_verbosity = 3
> debug_level = 9
> 
> [domain/nat.c.example.com]
> 
> debug_level = 9
> ad_domain = nat.c.example.com
> ad_hostname = host.nat.c.example.com
> krb5_realm = NAT.C.EXAMPLE.COM
> #cache_credentials = True
> id_provider = ad
> access_provider = ad
> chpass_provider = ad
> auth_provider = ad
> #
> krb5_store_password_if_offline = True
> default_shell = /bin/bash
> ldap_id_mapping = False
> use_fully_qualified_names = False
> #use_fully_qualified_names = True
> fallback_homedir = /home-local/%d/%u
> ldap_user_principal = userPrincipalName
> 
> ------
> On client machine , in the “Permission denied” session, all AD groups, ids are shown correctly using id, getent ;
> 
> Obviousely configuring nfs idmaping  requires special attention in multi domain trust ( doesn’t seem trivial using UMICH method!).
> May be some other AD specifics should be considered as well .

I don't know enough about NFSv4 + Kerberos to assess whether there is
some gotcha in that part of configuration, but I'll try to answer the
rest..

> 
> In the SSSD documentation is mentioned PAC service.
> Here come my questions:
> 
> Do we need PAC service enabled to get properly resolved AD groups in Kerberos context  between domains?

No. Also above you said that all groups are resolved correctly. Isn't
that the case?

> 
> IS it possible in the 1.11.7 version and with  (kernel 3.13.0-44) to  integrate  SSSD plugin  nfsidmap_sss.so introduced first in 1.12.1?

If you compile the plugin yourself, then yes. I'm not sure if it wold
help you, though.


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