samba - Jun 2023 - winbindd authentication fails with NT_STATUS_RPC_SEC_PKG_ERROR intermittently

A couple of things possible, from 4.8.0 winbind must be running and your
smb.conf is, to be blunt, rubbish. You need to set the workgroup, you
need to have idmap config lines for the workgroup, the 'winbind enum'
lines only slow things down and 'map untrusted to domain' has been
removed.

Winbind is running and the workgroup was set as well. I omitted some
lines from the smb.conf shared previously as I wasn't sure if they
were relevant or not. I've added the full content below. Also share is
being accessed by a windows client which is part of the domain and it
does work fine for a few hours after restarting the smbd and winbind
services. Does 'winbind enum' have any relation to that?

https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html#WINBINDENUMUSERS
mentions turning off 'winbind enum' can cause some problems

*Configuration:*

netbios name = clustF994DF
realm = <domain>

bind interfaces only = yes
interfaces = 127.0.0.138 lo:138

workgroup = <workgroup>
security = ads
server role = member server

auth methods = winbind

idmap config * : backend = tdb
idmap config * : range = 10000-24999999

winbind enum users = yes
winbind enum groups = yes
usershare allow guests = no

map untrusted to domain = Yes
allow trusted domains = no
server string = %h
dns proxy = no
log file = /var/log/samba/log.%m
max log size = 1000
panic action = /usr/share/samba/panic-action %d
smb ports = 1445
pid directory = /var/run/samba

server min protocol = SMB2
strict sync = yes
sync always = no

smb encrypt = auto

aio read size = 1
aio write size = 1

smb2 max read = 1048576
smb2 max write = 1048576
smb2 max trans = 1048576

socket options = TCP_NODELAY SO_RCVBUF=10485760 SO_SNDBUF=10485760

usershare owner only = no

load printers = no
printing = bsd
printcap name = /dev/null
disable spoolss = yes

machine password timeout = 0

nt acl support = yes
vfs objects = acl_xattr
map acl inherit = yes
store dos attributes = yes

log level = 5
max log size = 1000

*Share configuration:*

  path = <path>

  guest ok = no

  writeable = no

  browseable = no

  valid users =
"<domain>\<user>","+<domain>\<user
group>"

  force user = root

On Fri, Jun 2, 2023 at 3:21?AM Bharath Bheemarasetti <
bharath.bheemarasetti at gmail.com> wrote:
> Hi,
> I recently upgraded a smb server from Ubuntu 18.04 to Ubuntu 20.04 which
> required the Samba version to be upgraded from 4.7.6 to 4.15.13.
> Post the upgrade, winbind authentication fails
> with  NT_STATUS_RPC_SEC_PKG_ERROR intermittently. The error goes away on
> restarting the smb service but comes back after some time. There were no
> isses with the setup before the upgrade.
> Tried clearing the cached tdb files as well but the issue still come back
> after some time.
> <trimmed the log lines>
>
> Below is the configuration:
> security = ads
> server role = member server
> auth methods = winbind
> idmap config * : backend = tdb
> idmap config * : range = 10000-24999999
> winbind enum users = yes
> winbind enum groups = yes
> usershare allow guests = no
> map untrusted to domain = Yes
> allow trusted domains = no
>

On 03/06/2023 08:39, Bharath Bheemarasetti via samba
wrote:
>> 
> Winbind is running and the workgroup was set as well. I omitted some
> lines from the smb.conf shared previously as I wasn't sure if they
> were relevant or not. 
Can I ask that if anyone is going to post their smb.conf, they post it 
in its entirety, fragments are useless.

I've added the full content below. Also share is
> being accessed by a windows client which is part of the domain and it
> does work fine for a few hours after restarting the smbd and winbind
> services. Does 'winbind enum' have any relation to that?
First 'winbind enum' lines, they can and do slow things down in large 
domains and aren't required at all, getent etc will work without them. 
there are some old programs that will not work without them, but when 
was the last time you ran 'finger' for instance ?

 From your smb.conf below, it looks like you are putting everything into 
the default '*' domain, because you haven't got any 'idmap
config' lines
for the 'workgroup' domain.

Have you read the wiki pages I pointed you to ?

You might also want to read the smb.conf manpage, you have lots of lines 
that I would never set.
You also have 'smb ports = 1445'. Is this a typo ?

Rowland
> 
>
https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html#WINBINDENUMUSERS
> mentions turning off 'winbind enum' can cause some problems
> 
> *Configuration:*
> 
> netbios name = clustF994DF
> realm = <domain>
> 
> bind interfaces only = yes
> interfaces = 127.0.0.138 lo:138
> 
> workgroup = <workgroup>
> security = ads
> server role = member server
> 
> auth methods = winbind
> 
> idmap config * : backend = tdb
> idmap config * : range = 10000-24999999
> 
> winbind enum users = yes
> winbind enum groups = yes
> usershare allow guests = no
> 
> map untrusted to domain = Yes
> allow trusted domains = no
> server string = %h
> dns proxy = no
> log file = /var/log/samba/log.%m
> max log size = 1000
> panic action = /usr/share/samba/panic-action %d
> smb ports = 1445
> pid directory = /var/run/samba
> 
> server min protocol = SMB2
> strict sync = yes
> sync always = no
> 
> smb encrypt = auto
> 
> aio read size = 1
> aio write size = 1
> 
> smb2 max read = 1048576
> smb2 max write = 1048576
> smb2 max trans = 1048576
> 
> socket options = TCP_NODELAY SO_RCVBUF=10485760 SO_SNDBUF=10485760
> 
> usershare owner only = no
> 
> load printers = no
> printing = bsd
> printcap name = /dev/null
> disable spoolss = yes
> 
> machine password timeout = 0
> 
> nt acl support = yes
> vfs objects = acl_xattr
> map acl inherit = yes
> store dos attributes = yes
> 
> log level = 5
> max log size = 1000
> 
> *Share configuration:*
> 
>    path = <path>
> 
>    guest ok = no
> 
>    writeable = no
> 
>    browseable = no
> 
>    valid users =
"<domain>\<user>","+<domain>\<user
group>"
> 
>    force user = root
> 
> On Fri, Jun 2, 2023 at 3:21?AM Bharath Bheemarasetti <
> bharath.bheemarasetti at gmail.com> wrote:
> 
>> Hi,
>> I recently upgraded a smb server from Ubuntu 18.04 to Ubuntu 20.04
which
>> required the Samba version to be upgraded from 4.7.6 to 4.15.13.
>> Post the upgrade, winbind authentication fails
>> with  NT_STATUS_RPC_SEC_PKG_ERROR intermittently. The error goes away
on
>> restarting the smb service but comes back after some time. There were
no
>> isses with the setup before the upgrade.
>> Tried clearing the cached tdb files as well but the issue still come
back
>> after some time.
>> <trimmed the log lines>
>>
> 
>> Below is the configuration:
>> security = ads
>> server role = member server
>> auth methods = winbind
>> idmap config * : backend = tdb
>> idmap config * : range = 10000-24999999
>> winbind enum users = yes
>> winbind enum groups = yes
>> usershare allow guests = no
>> map untrusted to domain = Yes
>> allow trusted domains = no
>>

First 'winbind enum' lines, they can and do slow things down in large
domains and aren't required at all, getent etc will work without them.
there are some old programs that will not work without them, but when
was the last time you ran 'finger' for instance ?

I made this change and it makes some difference but doesn't fix the
issue entirely. Earlier the auth calls used to fail in around a day
which has increased to 2 days now after which the auth calls fail with
NT_STATUS_RPC_SEC_PKG_ERROR and winbind needs to be restarted for it
to work. We use NTLMv2 for authentication and using the ntlm_auth tool
(https://www.samba.org/samba/docs/current/man-html/ntlm_auth.1.html)
returns the same NT_STATUS_RPC_SEC_PKG_ERROR error as well while
wbinfo -i returns the correct user info.

Is there anything else that can be done to fix this permanently?

You might also want to read the smb.conf manpage, you have lots of lines
that I would never set.

Thanks, I removed some lines which are not used anymore and will be
cleaning up others shortly.


On Sat, Jun 3, 2023 at 1:09?PM Bharath Bheemarasetti <
bharath.bheemarasetti at gmail.com> wrote:
> A couple of things possible, from 4.8.0 winbind must be running and your
> smb.conf is, to be blunt, rubbish. You need to set the workgroup, you
> need to have idmap config lines for the workgroup, the 'winbind
enum'
> lines only slow things down and 'map untrusted to domain' has been
removed.
>
> Winbind is running and the workgroup was set as well. I omitted some lines
from the smb.conf shared previously as I wasn't sure if they were relevant
or not. I've added the full content below. Also share is being accessed by a
windows client which is part of the domain and it does work fine for a few hours
after restarting the smbd and winbind services. Does 'winbind enum' have
any relation to that?
>
>
https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html#WINBINDENUMUSERS
mentions turning off 'winbind enum' can cause some problems
>
> *Configuration:*
>
> netbios name = clustF994DF
> realm = <domain>
>
> bind interfaces only = yes
> interfaces = 127.0.0.138 lo:138
>
> workgroup = <workgroup>
> security = ads
> server role = member server
>
> auth methods = winbind
>
> idmap config * : backend = tdb
> idmap config * : range = 10000-24999999
>
> winbind enum users = yes
> winbind enum groups = yes
> usershare allow guests = no
>
> map untrusted to domain = Yes
> allow trusted domains = no
> server string = %h
> dns proxy = no
> log file = /var/log/samba/log.%m
> max log size = 1000
> panic action = /usr/share/samba/panic-action %d
> smb ports = 1445
> pid directory = /var/run/samba
>
> server min protocol = SMB2
> strict sync = yes
> sync always = no
>
> smb encrypt = auto
>
> aio read size = 1
> aio write size = 1
>
> smb2 max read = 1048576
> smb2 max write = 1048576
> smb2 max trans = 1048576
>
> socket options = TCP_NODELAY SO_RCVBUF=10485760 SO_SNDBUF=10485760
>
> usershare owner only = no
>
> load printers = no
> printing = bsd
> printcap name = /dev/null
> disable spoolss = yes
>
> machine password timeout = 0
>
> nt acl support = yes
> vfs objects = acl_xattr
> map acl inherit = yes
> store dos attributes = yes
>
> log level = 5
> max log size = 1000
>
> *Share configuration:*
>
>   path = <path>
>
>   guest ok = no
>
>   writeable = no
>
>   browseable = no
>
>   valid users =
"<domain>\<user>","+<domain>\<user
group>"
>
>   force user = root
>
> On Fri, Jun 2, 2023 at 3:21?AM Bharath Bheemarasetti <
> bharath.bheemarasetti at gmail.com> wrote:
>
>> Hi,
>> I recently upgraded a smb server from Ubuntu 18.04 to Ubuntu 20.04
which
>> required the Samba version to be upgraded from 4.7.6 to 4.15.13.
>> Post the upgrade, winbind authentication fails
>> with  NT_STATUS_RPC_SEC_PKG_ERROR intermittently. The error goes away
on
>> restarting the smb service but comes back after some time. There were
no
>> isses with the setup before the upgrade.
>> Tried clearing the cached tdb files as well but the issue still come
back
>> after some time.
>> <trimmed the log lines>
>>
>
>> Below is the configuration:
>> security = ads
>> server role = member server
>> auth methods = winbind
>> idmap config * : backend = tdb
>> idmap config * : range = 10000-24999999
>> winbind enum users = yes
>> winbind enum groups = yes
>> usershare allow guests = no
>> map untrusted to domain = Yes
>> allow trusted domains = no
>>
>