====== Fix "bad owner or permissions" for SSH in Cygwin ======

When I upgraded my Cygwin installation from 1.7.33 to 1.7.34, I started to get a "bad owner or permission" error message when I'd start a SSH connection. I searched the web for a couple of days but every website that I went to said to do:<code bash>
cd .ssh
chmod 600 config
chmod 600 id_rsa
</code>
Unfortunately, every time I'd execute that, the permissions would not change and I see this for the directory listing:<code bash>
user@LAPTOP:~/.ssh
$ dir
total 72K
d---rwx---+ 1 user Domain Users    0 Feb  1 18:46 .
d---rwx---+ 1 user Domain Users    0 Jan 31 20:57 ..
----rwx---+ 1 user Domain Users 1.5K Oct 29 18:13 config
----rwx---+ 1 user Domain Users 1.7K May 18  2013 id_github
----rwx---+ 1 user Domain Users 1.5K Aug  6  2014 id_github.ppk
----rwx---+ 1 user Domain Users 1.7K Feb 17  2013 id_host1
----rwx---+ 1 user Domain Users 1.5K Aug  6  2014 id_host1.ppk
----rwx---+ 1 user Domain Users 1.7K May  5  2014 id_host2
----rwx---+ 1 user Domain Users 1.7K May 18  2013 id_host3
----rwx---+ 1 user Domain Users 1.7K Mar  8  2011 id_host4
----rwx---+ 1 user Domain Users  883 Jan 14  2013 id_rsa
----rwx---+ 1 user Domain Users 8.7K Feb  1 14:15 known_hosts
</code>
I finally came across a [[https://www.cygwin.com/ml/cygwin/2014-12/msg00219.html|mailing list post]] talking about how the new version of Cygwin took ACLs into account when calculating permissions. This turned out to be the answer and directed me toward the solution:<code bash>
setfacl --s user::rw-,group::---,other::---,mask::--- config
setfacl --s user::rw-,group::---,other::---,mask::--- id_github
setfacl --s user::rw-,group::---,other::---,mask::--- id_host1
setfacl --s user::rw-,group::---,other::---,mask::--- id_host2
setfacl --s user::rw-,group::---,other::---,mask::--- id_host3
setfacl --s user::rw-,group::---,other::---,mask::--- id_host4
setfacl --s user::rw-,group::---,other::---,mask::--- id_rsa
</code>
which then gave me the correct permissions:<code bash>
user@LAPTOP:~/.ssh
$ dir
total 72K
d---rwx---+ 1 user Domain Users    0 Feb  1 18:46 .
d---rwx---+ 1 user Domain Users    0 Jan 31 20:57 ..
-rw-------  1 user Domain Users 1.5K Oct 29 18:13 config
-rw-------  1 user Domain Users 1.7K May 18  2013 id_github
----rwx---+ 1 user Domain Users 1.5K Aug  6  2014 id_github.ppk
-rw-------  1 user Domain Users 1.7K Feb 17  2013 id_host1
----rwx---+ 1 user Domain Users 1.5K Aug  6  2014 id_host1.ppk
-rw-------  1 user Domain Users 1.7K May  5  2014 id_host2
-rw-------  1 user Domain Users 1.7K May 18  2013 id_host3
-rw-------  1 user Domain Users  883 Mar  8  2011 id_host4
-rw-------  1 user Domain Users 1.7K Jan 14  2013 id_rsa
----rwx---+ 1 user Domain Users 8.7K Feb  1 14:15 known_hosts
</code>
After this, SSH worked the same as when Cygwin 1.7.33 was installed. I'm not sure if SSH was upgraded during upgrade so it may have been the result of a newer version of OpenSSH. Checking the version indicates that the binary was most likely part of the upgrade:<code bash>
user@LAPTOP:~/
$ ssh -V
OpenSSH_6.7p1, OpenSSL 1.0.1k 8 Jan 2015
</code>