I’ve posted about my instance of this to the Cygwin mailing before, years ago and again just now, 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.

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),1007(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

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)

$ 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

$ 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

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

$ 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

$ echo replace the file > /cygdrive/p/Recipes/test001.txt
-bash: /cygdrive/p/Recipes/test001.txt: Permission denied

(note no 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--

 

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
$ ls /etc/group
/usr/bin/ls: cannot access '/etc/group': No such file or directory
$ ls /etc/groups
/usr/bin/ls: cannot access '/etc/groups': No such file or directory

(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

$

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:

$ 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.