Hey guys,

A couple of weeks I was improving my home NAS a little by adding cron scripts for backups and a couple of things, I've been logging in for a while and starting bash (installed with busybox) as its a little more feature filled than the terminal that comes default. Anyway, I'd done it so often (started /bin/bash, that is), and without thinking added /bin/bash as the login shell for the admin user (the only ssh account, unfortunately), without thinking that the the file doesn't actually appear until after my path has been built and the busybox sym-links are installed. So basically now I can't login as its not pointing at a valid root shell.

The things I’ve tried so far are:

- Basic telnet/SSH login attempts, running a command as part of the SSH statement (i.e ssh admin@qnap.****.local cat /etc/passwd)
- Issue chsh to attempt a login shell change (ssh admin@qnap.****.local chsh /bin/sh)
- Writing a dodgy web script (total failure)
- Writing one of the QNAP installable packages (a QPKG) which appear to have elevated system privileges during install (can’t find enough information)
- I can’t take the drive(s) out to replace the file easily as its 4x drives in RAID-5 and I don’t have a PC to load them into
- I also can’t wipe the device as it (to my knowledge) deletes all data off the drives in the process.

Any ideas, short of me buying a couple of 2TB drives to back everything up on to whilst I wipe it, I would just unplug all the drives and rebuild the mdadm software raid array temporarily on another machine, but I just don't have access to a computer at the moment, all I've got is laptops, we use macbooks at work and every single one of my friends owns a laptop too :P

Have you tried booting off a usb stick and recovering that way ?

I am not familiar with this particular device but AFAIK the drives just store data. I would say the operating system resides in flash memory and is part of the embedded computer. There might be a reset button but it probably just resets passwords and loads a default configuration as when you first turn it on. If you can not reload the OS from its web page tool I'm not sure there is anything you can do without being able to access an internal console port if one exists. You might want to contact the QNAP to seek their help.

Thanks for your replies, I'm looking into booting off a USB stick now, it's headless though so it makes it difficult to do any kind of debugging?

There's a reset button on the device, but I've done a bit of reading and apparently it kills data too from the RAID array.

You may be able to attach a usb serial adapter as well and redirect the console to another pc via minicom or hyperterm...

Would port forwarding get you anywhere? Does the system have any other users than root, and might they be able to ssh or telnet from the router to itself? (EDIT: I may have got confused about exactly how port forwarding works here.)

Do sftp or scp work, or any other file copying protocol? That would let you upload a new /etc/passwd to fix the problem.