With the kid in bed and the baby drifting off with a bottle (held by wife) I decided I'd sit down and try to crack this nut. Taking stock first, it turns out that the permissions on the following files have reverted to the fun_plug defaults:
/ffp/home/root directory (permissions should be 755)After setting these all to the right perms I rebooted the NAS (using the 'reboot' command from a telnet session). Lo and behold, I can subsequently no longer establish a SSH session to the NAS.
/ffp/home/root/.ssh directory (should be 700)
/ffp/home/root/.ssh/authorized_keys (should be 600)
/ffp/etc/ssh/* contents (should be 600)
/ffp/var/lib/sshd (700 will do)
/ffp/home/root has reverted to 777So there are the symptoms. Question is, what's the cause? It sounds like it might be down to a feature of the D-Link firmware. I can understand how brute-force setting of permissions might help keep the system stable for non-fun_plug users, but what a bummer for me. Now trying to reset the NAS to factory settings... no improvement. I give in.
/ffp/home/root/.ssh has reverted to 722
/ffp/home/root/.ssh/authorized_keys has reverted to 622
/ffp/etc/ssh/* has reverted to 622
/ffp/var/lib/sshd has reverted to 622