[Samba] User permissions of profile/home directory lost

Paul R. Ganci ganci at nurdog.com
Fri Mar 2 03:08:29 UTC 2018

On 03/01/2018 01:02 AM, Rowland Penny wrote:
> Is this a PDC (NT4-style domain) or an AD DC ?
> Either way, I have never heard of anything like this happening before,
> perhaps it might help if you post your smb.conf.

Hi Rowland,

Whatever is occurring has happened again today. I had to "chown -R" my 
wife's home/Profile directories and files. Very strange and makes me 
wonder if she doesn't have some kind of malware on her laptop. I am 
checking that now.

In any case let me answer your questions. The DC is an AD DC. I 
originally set it up with an early 4.0 version of Samba. Over time I 
haven't really done anything to the configuration. However, there were a 
few things necessary as the behavior of Samba ADs changed with new 
versions. Before I show the smb.conf file several historical things 
should be noted.

1.) I originally used a RID back-end. However, I was persuaded on a 
10/22/2013 thread to switch to an AD back-end. I did that but kept the 
RID generated UID/GID. You had mentioned in another thread that was 
confusing but I never changed to saner UIDs/GIDs because everything 
worked as it was.

2.) There is a long "server services" line that at one point you had 
questioned in an early thread when winbind on the DC behavior changed. 
You pointed out  what I had was equivalent to something simpler albeit I 
couldn't find the thread but it was around the time I updated from 
4.1.18 to 4.2.2.

3.) I have the winbind enum groups/users set to yes purposely. I have so 
few users there is no penalty really. It is nice to have getent 
enumerate all the users and groups for debug reasons. That is usually 
one of the first things I do after an upgrade.

4.) The original set up is what I could find on the web back in the fall 
of 2013 when I setup the domain. Everything has worked relatively 
flawlessly until this week (2/25/2018) so that is nearly 5 years without 
doing much maintenance except Samba updates.

Presently the AD DC runs on a Dell 2950iii with Centos 6.9, the Sernet 
packages version 4.7.5-10. I am not sure but I think this problem 
occurred with an update from a 4.7.4 version. I was thinking of 
downgrading to see if the problem disappears.

Here is a sanitized version of the smb.conf on the AD DC and some other 
linux stuff on the DC

         server string = Active Directory Server
         workgroup = MYDOM
         realm = MYDOM.NURDOG.COM
         netbios name = NIKITA
         server role = active directory domain controller
         server services = s3fs, rpc, nbt, wrepl, ldap, cldap, kdc, 
drepl, winbindd, ntp_signd, kcc, dnsupdate
         bind interfaces only = yes
         interfaces = br0 lo
         encrypt passwords = true
         kerberos method = secrets and keytab
         winbind use default domain = yes
         winbind offline logon = false
         winbind enum groups = yes
         winbind enum users = yes
#        winbind separator = +
         winbind nss info = rfc2307
         map untrusted to domain = no
         template homedir = /home/%U
         template shell = /bin/bash
         idmap_ldb:use rfc2307 = yes

         path = /var/lib/samba/sysvol/mydom.nurdog.com/scripts
         read only = No

         path = /var/lib/samba/sysvol
         read only = No

         path = /home/Profiles/
         read only = No

         path = /home
         read only = No

The two users have these IDs as determined by getent:

Home directories:
drwx------+ 43 MYDOM\mywife MYDOM\domain users  4096 Feb 28 23:02 
drwx------+ 80 MYDOM\me MYHOME\domain users 20480 Feb 28 08:21 my_home

Profile directories:
drwxrwx---+ 17 MYDOM\mywife MYDOMdomain users 4096 Mar  1 17:19 mywife.V2
drwxrwx---+ 20 MYDOM\me MYDOM\domain users 4096 Feb 28 20:15 me.V2

Everything looks just like I show when the problem occurs. There will be 
a permission denied error once the problem occurs even though everything 
looks good. It only happens to my wife's account. She is on a Windows 7 
Professional laptop for most of the day. I am always on linux and have 
not experienced any problems. The issue effects both the Windows and 
linux accounts. It really is like mywife's file ownership is lost even 
though linux says everything is good. And when the problem occurs, 
authentication still works. It is possible to logon to the DC with 
mywife's account but access to the home directory is denied. Very 
strange problem indeed.

Thank you for your help.
Paul (ganci at nurdog.com)
Cell: (303)257-5208

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