title: ssh authorized_keys file location and permissions
body: <p>I am confused on the permissions that ssh requires when dealing with custom <em>authorized_keys</em> files.</p>
  <p>For example, assuming that we have a server with the following line in <em>/etc/ssh/sshd_config</em>:</p>
  <pre><code>AuthorizedKeysFile .ssh/authorized_keys /etc/ssh/authorized_keys
  </code></pre>
  <p>It means that theoretically we can access the server with all the keys inserted in those two files, considering that <em>.ssh/authorized_keys</em> is a per-user file (meaning that we can log in with user root using the keys in <em>/etc/ssh/authorized_keys</em> and <em>/home/root/authorized_keys</em>).</p>
  <p>Now, how can this even work for a non-root user for <em>/etc/ssh/authorized_keys</em>, if when using the default mode <code>StrictMode yes</code> does not allow to use of the <em>authorized_keys</em> file unless the parent folders are with permission 0600 and owned by the user (which is not the case here) and the file is owned by the user and has permission 0700 (that we can assume is the case)?</p>
  <p>Ssh won't accept the keys in <em>/etc/ssh/authorized_keys</em> for a non-root user, since the permission are not correct for that user (the owner of <em>/etc/ssh</em> is <em>root</em>).</p>
  <p>Or am I missing something?</p>