Windows non-domain file access (protection) problems on SAMBA share -- years-long ongoing, usual advice doesn't work

[David Dyer-Bennet <dd-b at dd-b dot net>]

I've posted about my instance of this here before, years ago, and read a
lot of what's online about it. I've also asked people over in the
FreeNAS community (and gotten basicaly the same answer).  Basically
everything I can find says that the information is here
<https://cygwin.com/cygwin-ug-net/ntsec.html#ntsec-mapping-samba>.

What's there doesn't work for me.  Across many Cygwin installs on
multiple windows versions (at least 7 and 10) on at least 4 different
hardware platforms.  Including one work computer accessing a Synology
server, so *completely* different software on the server side (dev
network at work, no Active Directory there, so it's just like home,
local logons only).

The Samba server at home is a FreeNAS box. It's *not* joined to any
domain, nor are the windows boxes (it's at home, I have no AD server,
it's all local logons).  Currently running FreeNAS 11.1 U5, if it
matters (latest), which seems to be running samba version
4.7.0-GIT-de2f31198c7-FreeNAS.

Details will be from my Windows 10 desktop, where I did a clean install
of Cygwin-64 last night; it identifies itself (uname -a) as
CYGWIN_NT-10.0 DDB4 2.10.0(0.325/5/3) 2018-02-02 15:16 x86_64 Cygwin.

This box has accessed this server (multiple FreeNAS and hence Samba
servers over the years) as both Windows 7 and windows 10.  It works fine
in windows, I can adjust file security through the Windows explorer
dialogs, etc.  (My desktop computers, or my last 3 or 4 desktop
coumpters really, running windows and Cygwin in some version, has
accessed a file server via CIFS for most of my file access since about
2006; that fileserver has been Solaris with ZFS and then FreeNAS with
ZFS. I've also had at least three laptops configured to use this server
and having Cygwin, and they all behaved the same as the desktop at that
moment.  I started having protection problems when Cygwin made the
changes described in the link above.)

Cygwin works fine on locally-hosted files (not that I have many; a small
SSD for software installation, plus external drives I may attach from
time to time, everything important lives on the fileserver). The
protections Cygwin shows for files on the NAS look like what I will get
if the underlying problem *is* something related to the ntsec article
above.  That kinda gives me hope that I'm just doing something wrong
that I'm unable to spot.

On the FreeNAS box, user ddb (uid 1001) owns the files in question:

[root@fsfs /mnt/zp1/ddb/Documents/Recipes]# id ddb

uid=1001(ddb) gid=1001(ddb)
groups=1001(ddb),0(wheel),20(staff),1004(public),100
7(music),1712(bdr)
[root@fsfs /mnt/zp1/ddb/Documents/Recipes]# ls -l S*

-rwxrwxr-x+ 1 ddb  ddb   9605 May 30  2004 Sacher.asc

-rwxrwxr-x+ 1 ddb  ddb   9600 May 30  2004 Sacher.doc

-rwxrwxr-x+ 1 ddb  ddb   4867 May 30  2004 Salsa.asc

-rwxrwxr-x+ 1 ddb  ddb   4864 May 30  2004 Salsa.doc

-rwxrwxr-x+ 1 ddb  ddb   2181 May 30  2004 Shrmpstr.asc

-rwxrwxr-x+ 1 ddb  ddb   2176 May 30  2004 Shrmpstr.doc

-rwxrwxr-x+ 1 ddb  ddb  20841 Dec  4  2012 Spaghetti.odt

[root@fsfs /mnt/zp1/ddb/Documents/Recipes]#

Locally, it's mapped as Windows drive P: (at the 'Documents' level in
the above path), but also directly accessible as //fsfs/ddb/Documents.

$ id
uid=197612(ddb) gid=545(Users)
groups=545(Users),197121(None),197613(fsfsddb),4(INTERACTIVE),66049(CONSOLE
LOGON),11(Authenticated Users),15(This Organization),113(Local
account),66048(LOCAL),262154(NTLM Authentication),401408(Medium
Mandatory Level)
ddb@DDB4:~
$ ls -l /cygdrive/p/Recipes/S*
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 9.7k May 30  2004
/cygdrive/p/Recipes/Sacher.asc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 9.6k May 30  2004
/cygdrive/p/Recipes/Sacher.doc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 4.9k May 30  2004
/cygdrive/p/Recipes/Salsa.asc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 4.9k May 30  2004
/cygdrive/p/Recipes/Salsa.doc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 2.2k May 30  2004
/cygdrive/p/Recipes/Shrmpstr.asc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 2.2k May 30  2004
/cygdrive/p/Recipes/Shrmpstr.doc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001  21k Dec  4  2012
/cygdrive/p/Recipes/Spaghetti.odt
ddb@DDB4:~

ddb@DDB4:~
$ ls -l //fsfs/ddb/Documents/Recipes/S*
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 9.7k May 30  2004
//fsfs/ddb/Documents/Recipes/Sacher.asc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 9.6k May 30  2004
//fsfs/ddb/Documents/Recipes/Sacher.doc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 4.9k May 30  2004
//fsfs/ddb/Documents/Recipes/Salsa.asc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 4.9k May 30  2004
//fsfs/ddb/Documents/Recipes/Salsa.doc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 2.2k May 30  2004
//fsfs/ddb/Documents/Recipes/Shrmpstr.asc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001 2.2k May 30  2004
//fsfs/ddb/Documents/Recipes/Shrmpstr.doc
-rwxrwxr-x 1 Unknown+User Unix_Group+1001  21k Dec  4  2012
//fsfs/ddb/Documents/Recipes/Spaghetti.odt
ddb@DDB4:~

That "Unknown_User" is the signature of this problem, right?

And I can create a file, and read it, but not replace it:

$ echo testing > /cygdrive/p/Recipes/test001.txt
ddb@DDB4:~
$ ls -l /cygdrive/p/Recipes/test001.txt
----r--r-- 1 Unknown+User Unix_Group+1001 8 Jun 16 13:08
/cygdrive/p/Recipes/test001.txt
ddb@DDB4:~

(note now indication that there is an ACL; which is compatible with the
following)

$ getfacl /cygdrive/p/Recipes/test001.txt
# file: /cygdrive/p/Recipes/test001.txt
# owner: Unknown+User
# group: Unix_Group+1001
user::---
group::r--
other:r--

ddb@DDB4:~
$ cat /cygdrive/p/Recipes/test001.txt
testing
ddb@DDB4:~
$
ddb@DDB4:~
$ echo replace the file > /cygdrive/p/Recipes/test001.txt
-bash: /cygdrive/p/Recipes/test001.txt: Permission denied
ddb@DDB4:~

My Cygwin setup doesn't have /etc/passwd or /etc/groups

$ ls /etc/passwd
/usr/bin/ls: cannot access '/etc/passwd': No such file or directory
ddb@DDB4:~
$ ls /etc/group
/usr/bin/ls: cannot access '/etc/group': No such file or directory
ddb@DDB4:~
$ ls /etc/groups
/usr/bin/ls: cannot access '/etc/groups': No such file or directory
ddb@DDB4:~
$
(Wasn't absolutely sure of my memory whether group was plural or not :-(
; but neither one exists.)

I have configured /etc/nsswitch as I believe is directed (everything
left defaults, except change db_gecos to schema "desc"):

$ cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
#    This file is read once by the first process in a Cygwin process tree.
#    To pick up changes, restart all Cygwin processes.  For a description
#    see https://cygwin.com/cygwin-ug-net/ntsec.html#ntsec-mapping-nsswitch
#
# Defaults:
# passwd:   files db
# group:    files db
# db_enum:  cache builtin
# db_home:  /home/%U
# db_shell: /bin/bash
# db_gecos: <empty>

db_gecos: desc
ddb@DDB4:~
$

I have configured the user comment for me, user ddb, in SAM, via the net
user command, to have the xml-like Cygwin data in the comment:

$ net user ddb
User name                    ddb
Full Name                    David Dyer-Bennet
Comment                      <cygwin unix="1001" group="Users" />
User's comment
Country/region code          000 (System Default)
Account active               Yes
Account expires              Never

Password last set            6/2/2017 11:17:13 PM
Password expires             Never
Password changeable          6/2/2017 11:17:13 PM
Password required            Yes
User may change password     Yes

Workstations allowed         All
Logon script
User profile
Home directory
Last logon                   6/16/2018 12:26:50 PM

Logon hours allowed          All

Local Group Memberships      *Administrators       *fsfsddb
                             *Users
Global Group memberships     *None
The command completed successfully.

And I have also done that for the group:

ddb@DDB4:~
$ net localgroup Users
Alias name     Users
Comment        <cygwin unix="1001" />

Members

-------------------------------------------------------------------------------
admin
ddb
localddb
NT AUTHORITY\Authenticated Users
NT AUTHORITY\INTERACTIVE
The command completed successfully.

And I have rebooted the entire Windows box more than once since I last
changed anything in the Cygwin config, so the config shown should be in
effect when Cygwin produced the output posted above.

(I've tried what seems like a million things over the years, but this is
the mainline approach to the problem as described in the NTSEC article,
and I went through *very* carefully last night to do everything I found
in the article about how I was supposed to do it, and documented all the
things I've done to produce this email).

So...HELP!  I feel like this is supposed to be an understood problem,
and that I have *done* everything the main article says I'm supposed to
do -- and it hasn't helped.  Did I miss a step or something?  Any ideas?
 I have this across multiple software versions on both sides and
multiple hardware platforms and installations; it's not some one-time thing.
-- 
David Dyer-Bennet <dd-b@dd-b.net>
http://dd-b.net/

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