[Samba] Order of getpwnam call in Get_Pwnam_internals.

[Rowland Penny]

On Thu, 25 Jan 2024 20:54:07 +0800
hhyy ww via samba <samba at lists.samba.org> wrote:

> Rowland Penny via samba <samba at lists.samba.org> 於 2024年1月25日 週四
> 下午6:42寫道：
> 
> > On Thu, 25 Jan 2024 18:27:48 +0800
> > hhyy ww via samba <samba at lists.samba.org> wrote:
> >
> > > Hi list,
> > >
> > > My case :
> > > Local UNIX user : ZTEST
> > > domain : uuq.ork
> > > domain user : UUQ\ztest
> > > smb.conf for standalone samba : /home/hywu/smb.conf
> > >
> > > [/home/hywu] # cat /home/hywu/smb.conf
> > > [global]
> > > passdb backend = smbpasswd
> > > workgroup = WORKGROUP
> > > security=user
> >
> > Why is the smb.conf file in /home/hywu instead of somewhere like
> > /etc/samba ?
> >
> > >
> > > Smbpasswd fail to change local UNIX user password (ZTEST) when
> > > samba role is DC. I want to change password of local UNIX user
> > > "ZTEST" but get domain user "UUQ\ztest" from
> >
> > You shouldn't have local and domain users with the same name.
> >
> 
> > >
> > >
> > > root at uuu:/# getent passwd | tail
> > > hywu:x:1000:1000 hywu,,,:/home/hywu:/bin/bash
> > > sshd:X:128:65534::/run/sshd:/usr/sbin/nologin
> > > jone:x:1001:1001:,,,:/home/jone:/bin/bash
> > > ZTEST:X:1002:1002:,,,:/home/ZTEST: /bin/bash
> > > UUQ\administrator:*:0:100::/home/UUQ/administrator:/bin/false
> > > UUQ\guest:*:3000008:100::/home/UUQ/guest :/bin/false
> > > UUQ\krbtgt:*:3000012:100::/home/UUQ/krbtgt:/bin/false
> > > UUQ\ztest:*:3000013:100::/home/UUQ/ztest:/bin/false
> >
> > Go on, I give in, how did you get a domain user into /etc/passwd
> > (where it doesn't belong).
> >
> 
> After samba role become DC ,I add winbind to passwd and group section
> in /etc/nsswitch.conf

That would not put anything into /etc/passwd, but thinking about it, do
you have 'winbind enum users = yes' in your correct smb.conf ?

> 
> >
> 
> > root at uuu:/#
> > > root at uuu:/#smbpasswd -c /home/hywu/smb.conf -U ZTEST -D 2
> > > rlimit max:increasing (1024) to minimum Windows limit (16384)
> > > New SMB password:
> > > Retype new SMB password:
> > > Cannot update entry for user UUQ\ztest, as they don't exist in the
> > > smbpasswd file!
> > > smbpasswd_update_sam_account: mod_smbfilepud_entry failed!
> > > Failed to modify entry for user ZTEST.
> > > root at uuu:/# uname -a
> > > Linux uuu 6.5.0-14-generic #14~22.04.1-Ubuntu SMP...
> > >
> > >
> > > I checked samba code then I found the problem is order of gerpwnam
> > > call in Get_Pwnam_internals(). Lowercase first order will get
> > > domain user (UUQ/ztest) but local account(ZTEST).
> > >
> > > local_password_change()
> > >  pdb_getsampwnam()
> > >   smbpasswd_getsampwnam()
> > >     build_sam_account()
> > >      Get_Pwnam_alloc()
> > >       Get_Pwnam_internals() <-- turn "ZTEST" to "ztest"
> > >        getpwnam_alloc_cached()
> > >         getpwnam()
> > >          (nss_winbinadd)
> > >           winbindd_getpwnam_send()
> > >            parse_domain_user() <-- add "UUQ" to domain and
> > > namespace. assume_domain()
> > >
> > > When samba role is DC , "winbind use default domain" does not
> > > work in assume_domain(). Then getpwnam() get domain user.
> > >
> > > I have checked the following list and commit
> > >
> > https://lists.samba.org/archive/samba-technical/2008-March/058508.htmlhttps://git.samba.org/?p=samba.git;a=commitdiff;h=ea4a0d509ef70e91baedc5eebf4f4bcff10dac96
> > >
> > > Why the order of getpwnam call in Get_Pwnam_internals() change
> > > from original name first to lowercase first?
> > >
> > > HY Wu.
> >
> > I think you need to give us more details:
> > What OS ?
> >
> ubuntu 22.04
> 
> > What version of Samba ?
> >
> samba-4.15
> 
> > Is there another smb.conf file somewhere ?
> >
> Before samba role become DC , samba use this smb.conf.
> [/home/hywu] # cat /home/hywu/smb.conf [global] passdb backend =
> smbpasswd workgroup = WORKGROUP security=user
> 
> After samba role become DC, samba use smb.conf generated by samba-tool
> domain prvision.
> 
> 
> > If there is, what is in it ?
> > How did you provision the domain, what was the actual command ?
> >
>  samba-tool domain provision --use-rfc2307 --realm=uuq.ork
> --domain=UUQ --server-role=DC --adminpass=xxxxxx
> I install samba following there links
> https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_Domain_Controller#Introduction
> https://wiki.samba.org/index.php/Distribution-specific_Package_Installation#Debian/Ubuntu
> 
> > Rowland
> >
> >
> > --
> > To unsubscribe from this list go to the following URL and read the
> > instructions:  https://lists.samba.org/mailman/options/samba
> 
> I need to sync account password in  /etc/passwd and smbpasswd so when
> I change local user password I run smbpasswd command to set the same
> password. Before samba become DC, "smbpasswd -c /home/hywu/smb.conf
> -U ZTEST" works well.
> After samba become DC, this command fail to change password.
> I check debug log and samba code, I find the order of getpwnam call in
> Get_Pwnam_internals cause this problem.
> 
> HY Wu.

You only need local Unix users (the ones that are in /etc/passwd) on a
Samba AD DC for local administration and as I said earlier, any local
Unix users are unknown to AD.

If I run getent on one of my DCs, I get thing like this:

adminuser at rpidc1:~ $ getent passwd rowland
SAMDOM\rowland:*:3000020:100:Rowland Penny:/home/SAMDOM/rowland:/bin/bash

To all intents and purposes, 'rowland' is a local Unix user and can log
into the DC, but 'rowland' isn't in /etc/passwd:

adminuser at rpidc1:~ $ cat /etc/passwd | grep 'rowland'
adminuser at rpidc1:~ $ 
adminuser at rpidc1:~ $ 

To change an AD users password, you can use samba-tool, see:

samba-tool user password --help

Or:

samba-tool user setpassword --help

I would remove any users from /etc/passwd that are also created in your
AD DC

I will now go and close your bug report, it is invalid.

Rowland