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Raison D'être

I am attempting, so far unsuccessfully, to house roaming profiles for an Active Directory domain on a realm trusted Ubuntu 12.04LTS ZFS-on-Linux file server. The end goal is to have an inter-operable file server to house autofs nfs home directories for Linux and roaming profiles for Windows. It is politically difficult for me to do this purely with Windows Servers or joining Linux servers into Active Directory. As such, I am looking for technical solutions or proof that such technical solutions are less tenable than fighting political battles.

I suspect my current difficulty has something to do with the windows client to samba interactions rather than zfs, but I'm a bit out of my depth, so I'm not ruling it completely out. Could you, dear reader, point out why what I'm doing is incorrect and explain the correct procedure?


What I think I know

  1. The user can successfully log onto the client machine from the kerberos realm. However, the user is logged in with a temporary profile.
  2. A profile folder is created (presumably by login process) on the file server, but no other files are made in that newly created profile folder.
  3. The profile folder is created automatically with the proper owner/group.
  4. Given that, it seems unlikely the the profile is loaded before the credential cache is instantiated or the krbtgt is granted.
  5. While logged into the temporary profile, the user can create files on the file server without having to supply the file server with any (additional) credentials. That is there is no prompt. These files are also created with the proper owner/group.

Additional Information

This is all the configuration I think you'll want to know about, but I could be wrong.
I apologize for not finding a way to have it be collapsible.

A Brief Overview of Systems and Machines Involved

AD domain: ad.example.com  (Functional Level 2012)
domain controllers: dc1.ad.example.com, dc2.ad.example.com (OS: Windows Server 2012 Std)
mit-krb5 realm: EXAMPLE.COM  
mit-krb5 kdcs: kdc1.example.com, kdc2.example.com (mit-krb5: 1.9.4)
smb/cifs server: zfs.example.com  (OS: Ubuntu 12.04LTS)
client: client.ad.example.com (OS: Windows 8 Enterprise)

The Samba Log

root@zfs:~# cat /var/log/samba/client.log
[2013/06/14 14:37:26.194496,  0] param/loadparm.c:9114(process_usershare_file)
  process_usershare_file: stat of /var/lib/samba/usershares/tank_test failed. Permission denied
[2013/06/14 14:37:26.460344,  0] param/loadparm.c:9114(process_usershare_file)
  process_usershare_file: stat of /var/lib/samba/usershares/tank_test failed. Permission denied
[2013/06/14 14:44:04.352344,  0] param/loadparm.c:9114(process_usershare_file)
  process_usershare_file: stat of /var/lib/samba/usershares/tank_test failed. Permission denied

Not sure what it's complaining about...

root@zfs:~# ls -l /var/lib/samba/usershares/tank_test
-rw-r--r-- 1 root root 110 Jun 14 12:57 /var/lib/samba/usershares/tank_test

The File Server Share Pre-login

root@zfs:~# ls -la /tank/test/
total 38
drwxrwxrwt 2 root root 2 Jun 14 09:12 .
drwxr-xr-x 5 root root 5 Jun 13 15:52 ..

File Server Share Post-login:

root@zfs:~# ls -la /tank/test/
total 57
drwxrwxrwt 3 root root 3 Jun 14 09:16 .
drwxr-xr-x 5 root root 5 Jun 13 15:52 ..
drwxr-xr-x 2 user user 2 Jun 14 09:16 user.V2
root@zfs:~# find /tank/test
/tank/test
/tank/test/user.V2/

User's Credential Cache upon Login

Current LogonId is 0:0x6c79e3

Cached Tickets: (7)

#0> Client: user @ EXAMPLE.COM
    Server: krbtgt/EXAMPLE.COM @ EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x60a90000 -> forwardable forwarded renewable pre_authent name_canonicalize 0x80000
    Start Time: 6/14/2013 14:44:24 (local)
    End Time:   6/15/2013 2:44:24 (local)
    Renew Time: 6/21/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0x2 -> DELEGATION 
    Kdc Called: kdc2.example.com

#1> Client: user @ EXAMPLE.COM
    Server: krbtgt/AD.EXAMPLE.COM @ EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x40a90000 -> forwardable renewable pre_authent name_canonicalize 0x80000
    Start Time: 6/14/2013 14:44:24 (local)
    End Time:   6/15/2013 2:44:24 (local)
    Renew Time: 6/14/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0 
    Kdc Called: kdc2.example.com

#2> Client: user @ EXAMPLE.COM
    Server: krbtgt/EXAMPLE.COM @ EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x40e10000 -> forwardable renewable initial pre_authent name_canonicalize 
    Start Time: 6/14/2013 14:44:24 (local)
    End Time:   6/15/2013 2:44:24 (local)
    Renew Time: 6/21/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0x1 -> PRIMARY 
    Kdc Called: kdc2.example.com

#3> Client: user @ EXAMPLE.COM
    Server: ldap/dc1.ad.example.com @ AD.EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x40a50000 -> forwardable renewable pre_authent ok_as_delegate name_canonicalize 
    Start Time: 6/14/2013 14:44:31 (local)
    End Time:   6/15/2013 0:44:31 (local)
    Renew Time: 6/14/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0 
    Kdc Called: dc1.ad.example.com

#4> Client: user @ EXAMPLE.COM
    Server: LDAP/dc1.ad.example.com/ad.example.com @ AD.EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x40a50000 -> forwardable renewable pre_authent ok_as_delegate name_canonicalize 
    Start Time: 6/14/2013 14:44:25 (local)
    End Time:   6/15/2013 0:44:25 (local)
    Renew Time: 6/14/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0 
    Kdc Called: dc1.ad.example.com

#5> Client: user @ EXAMPLE.COM
    Server: cifs/dc1.ad.example.com @ AD.EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x40a50000 -> forwardable renewable pre_authent ok_as_delegate name_canonicalize 
    Start Time: 6/14/2013 14:44:24 (local)
    End Time:   6/15/2013 0:44:24 (local)
    Renew Time: 6/14/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0 
    Kdc Called: dc1.ad.example.com

#6> Client: user @ EXAMPLE.COM
    Server: cifs/zfs.example.com @ EXAMPLE.COM
    KerbTicket Encryption Type: AES-256-CTS-HMAC-SHA1-96
    Ticket Flags 0x40a90000 -> forwardable renewable pre_authent name_canonicalize 0x80000
    Start Time: 6/14/2013 14:44:24 (local)
    End Time:   6/15/2013 2:44:24 (local)
    Renew Time: 6/14/2013 14:44:24 (local)
    Session Key Type: AES-256-CTS-HMAC-SHA1-96
    Cache Flags: 0 
    Kdc Called: kdc2.example.com

The REALM Trust

ldapsearch -h ad.example.com -LLL cn=EXAMPLE.COM  objectClass trustPartner instancetype trustDirection trustAttributes
SASL/GSSAPI authentication started
SASL username: user@EXAMPLE.COM
SASL SSF: 56
SASL data security layer installed.
dn: CN=EXAMPLE.COM,CN=System,DC=ad,DC=example,DC=com
objectClass: top
objectClass: leaf
objectClass: trustedDomain
instanceType: 4
trustDirection: 3
trustPartner: EXAMPLE.COM
trustAttributes: 1

The Active Directory User

ldapsearch -h ad.example.com -LLL samaccountname=user profilePath altSecurityIdentities
SASL/GSSAPI authentication started
SASL username: user@EXAMPLE.COM
SASL SSF: 56
SASL data security layer installed.
dn: CN=Test User,OU=managed users,DC=ad,DC=example,DC=com
profilePath: \\zfs.example.com\tank_test\user
altSecurityIdentities: Kerberos:user@EXAMPLE.COM

The Basic ZFS information

root@zfs:~#  zfs get mountpoint,casesensitivity,sharesmb,available tank/test
NAME       PROPERTY         VALUE        SOURCE
tank/test  mountpoint       /tank/test   default
tank/test  casesensitivity  mixed        -
tank/test  sharesmb         on           local
tank/test  available        26.1T        -

ZFS created smb share root@zfs:~# cat /var/lib/samba/usershares/tank_test #VERSION 2 path=/tank/test comment=Comment: /tank/test usershare_acl=S-1-1-0:F guest_ok=n sharename=tank_test

The Samba Configuration

root@zfs:~# grep -v -e ^$ -e ^\; -e ^# /etc/samba/smb.conf
[global]
   workgroup = EXAMPLE.COM
   server string = %h server (Samba, Ubuntu)
   dns proxy = no
   log file = /var/log/samba/%M.log
   max log size = 1000
   syslog = 3
   panic action = /usr/share/samba/panic-action %d
security = ADS
realm = EXAMPLE.COM
kerberos method = system keytab
map to guest = bad user

The File Server's Keytab

root@zfs:~# ktutil
ktutil:  rkt /etc/krb5.keytab
ktutil:  list -e
slot KVNO Principal
---- ---- ---------------------------------------------------------------------
   1    2  host/zfs.example.com@EXAMPLE.COM (aes256-cts-hmac-sha1-96)
   2    2  host/zfs.example.com@EXAMPLE.COM (aes128-cts-hmac-sha1-96)
   3    2  host/zfs.example.com@EXAMPLE.COM (arcfour-hmac)
   4    2   nfs/zfs.example.com@EXAMPLE.COM (aes256-cts-hmac-sha1-96)
   5    2   nfs/zfs.example.com@EXAMPLE.COM (aes128-cts-hmac-sha1-96)
   6    2   nfs/zfs.example.com@EXAMPLE.COM (arcfour-hmac)
   7    2  cifs/zfs.example.com@EXAMPLE.COM (aes256-cts-hmac-sha1-96)
   8    2  cifs/zfs.example.com@EXAMPLE.COM (aes128-cts-hmac-sha1-96)
   9    2  cifs/zfs.example.com@EXAMPLE.COM (arcfour-hmac)

The Server's Identity Mapping (via sssd)

root@zfs:~# cat /etc/sssd/sssd.conf
# SSSD configuration generated using /usr/lib/sssd/generate-config
[sssd]
config_file_version = 2
reconnection_retries = 3
sbus_timeout = 30
services = nss, pam
domains = example.com
[nss]
filter_groups = root
filter_users = root
reconnection_retries = 3
[pam]
reconnection_retries = 3
[domain/example.com]
enumerate = false
cache_credentials = true
id_provider = ldap
auth_provider = krb5
chpass_provider = krb5
ldap_uri = ldap://ldap.example.com
ldap_search_base = dc=example,dc=com
ldap_tls_reqcert = demand
ldap_tls_cacert = /etc/ssl/certs/ca-certificates.crt
krb5_kdcip = kerberos.example.com
krb5_realm = EXAMPLE.COM
krb5_changepw_principle = kadmin/changepw
krb5_auth_timeout = 15

The Server's (Relavent) Packages

root@zfs:~# uname -a
Linux zfs 3.5.0-23-generic #35~precise1-Ubuntu SMP Fri Jan 25 17:13:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
root@zfs:~# dpkg --get-selections | grep -e samba -e zfs -e krb -e sssd
krb5-config                                     install
krb5-locales                                    install
krb5-user                                       install
libgssapi-krb5-2                                install
libkrb5-26-heimdal                              install
libkrb5-3                                       install
libkrb5support0                                 install
libpam-krb5                                     install
libzfs1                                         install
samba                                           install
samba-common                                    install
samba-common-bin                                install
samba-tools                                     install
sssd                                            install
ubuntu-zfs                                      install
zfs-dkms                                        install
zfsutils                                        install
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1 Answer 1

up vote 1 down vote accepted

By default Windows clients must verify a roaming profile folders ACLs by using use SIDs when loading the roaming profiles. Even having the Active Directory user with the same uid, uidNumber, gidNumber and a proper altSecurityIdentites attribute is insufficient.

While the SID requirement cannot be disabled. The ACL check itself can be. The folder must still be readable by either the user or the Administrators group.
Under Server 2012 this policy is called
Do not check for user ownership of Roaming Profile Folders
and is found at
Computuer Configuration \ Administrative Templates \ System \ User Profiles


I should have looked at the Windows client logs earlier; I've not no excuse for that.

Windows log: Windows could not load your roaming profile and is attempting to log you on with your local profile. Changes to the profile will not be copied to the server when you log off. Windows could not load your profile because a server copy of the profile folder already exists that does not have the correct security. Either the current user or the Administrators group must be the owner of the folder.

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