Re: Help with standalone samba SID-uid mapping

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Jan 13 14:39, Chris Roehrig wrote:
> I'm trying to set up samba (standalone) following these instructions:
> 	https://cygwin.com/cygwin-ug-net/ntsec.html#ntsec-mapping-samba
> 
> but I'm having no luck getting my samba user/groups to appear correctly using the <cygwin unix="601"/> comment field as described in the document.
> 
> I'm using samba 4.13.14 on Ubuntu 20.04 with security = user (smbpasswd).   winbindd is not installed and I'm not using any LDAP or AD anywhere.
> 
> E.g. here is what is on the server (croehrig:croehrig = 601:601; cristina:cristina = 603:603)
> housesrv[3]% ls -l /House/Users
> total 17
> drwxr-xr-x  9 cristina cristina 22 Jan 12 16:06 cristina
> drwxr-xr-x 30 croehrig croehrig 53 Jan 13 09:47 croehrig
> 
> 
> Here are the ACLs and SIDs when looking on the windows client:
> tyto[5]% icacls \\\\housesrv\\Users\\\*
> \\housesrv\Users\cristina S-1-5-21-751087815-2087572193-42305691-1001:(F)
>                           S-1-22-2-603:(RX)
>                           Everyone:(RX)
> 
> \\housesrv\Users\croehrig S-1-5-21-751087815-2087572193-42305691-1000:(F)
>                           S-1-22-2-601:(RX)
>                           Everyone:(RX)
> 
> As you can see, the gid is mapping to the S-1-22-2-<gid> as described
> in the document above, but the uid is using a domain-specific SID with
> different RIDs. 

These look like your standard Windows SIDs, so they are your SIDs for
users cristina and croehrig on Windows.  They should show up as such in
ls -l output, unless the SID is actuall wrong, e. g., they map to your
accounts on another machine or something like that.

> On the windows client I have the same users and groups set up locally
> (SAM) with appropriate SID mappings to the same uid/gids (601/603) in
> the Cygwin /etc/passwd and /etc/group.     This has all been working
> well to ensure e.g. rsync preserves permissions and ownership between
> cygwin and Linux.  (The windows groups are called 'grp-croehrig' and
> 'grp-cristina' since windows users and groups share a namespace, but
> they are mapped to 'croehrig' and 'cristina' in /etc/group).
> 
> 
> Here is how the SMB share looks under Cygwin:
> tyto[6]% ls -l //housesrv/Users/
> total 0
> drwxr-xr-x 1 Unknown+User Unix_Group+603 0 Jan 12 16:06 cristina
> drwxr-xr-x 1 Unknown+User Unix_Group+601 0 Jan 13 09:47 croehrig

Sorry, but I don't quite understand.  If you have matching /etc/passwd
and /etc/group files, and your /etc/nsswitch.conf allows reading the
files, this shouldn't happen.  Are the Windows SIDs correct?  Are they
matching your machine?


Corinna