[Samba] Not possible to chown as guest?

[john smith]

On 5/27/17, Rowland Penny via samba <samba at lists.samba.org> wrote:
> On Sat, 27 May 2017 04:31:07 +0900
> john smith via samba <samba at lists.samba.org> wrote:
>
>> > getent passwd nobody
>> > nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
>>
>> Ok, I know that. Please read my 1st post more carefully. I added my
>> nobody user to users group. I can log in as nobody on the server and
>> do `chown nobody:users <FILE>.
>
> To login, you must have given 'nobody' a password, given it a home
> directory and a shell that lets it login. Or do you mean that you can
> connect to a share as the user 'nobody' although this would still
> mean that 'nobody' has a password.

First I log in as root into my OpenWRT router and then just do `su
nobody'. Of course I had to enable nobody first by changing its shell
from /var/false to /bin/ash. After doing `su nobody':

uid=65534(nobody) gid=65534(nogroup) groups=100(users),65534(nogroup)

Note that it belongs to users group. As a user nobody I can create a file:

$ touch FILE
$ ls -l FILE
-rw-r--r--    1 nobody   nogroup          0 May 26 22:12 FILE

And change the file's group to users:

$ chown nobody:users FILE
$ ls -l FILE
-rw-r--r--    1 nobody   users            0 May 26 22:12 FILE

And it works.

Now, on my Linux box in /mnt/r when the router share is mounted as guest:

$ chown ja:users TEST-FILE
chown: changing ownership of 'TEST-FILE': Permission denied

I pasted the logs, both strace and Samba logs from the router in my
first post.

> still think this is a good idea ???

No, I don't.  I suggested 4 alternative ways to solve this problem in
my first post. I just want to know why can't I do chown as a guest in
a mounted directory.
-- 
<wempwer at gmail.com>