This tutorial is outdated and no longer maintained! Please check for the current tutorial here

The Conceptronic CH3SNAS runs an embedded version of theLinux operating system (OS). This includes a kernel and various Linux programs (mainly servers). Because the CH3SNAS (and many others) runs on an ARM processor, the executable version of Linux and the programs are binaries generated for the ARM processor.

The Firmwares includes a very interesting bonus: the user can execute a script (file) named “fun_plug” when the OS is booted. Unlike all the other Linux software which is loaded when the NAS boots, this file is located on Volume_1 of the hard disk rather than within the flash memory. This means the user can easily and safely modify the file because the contents of the flash memory is not changed. If you delete the fun_plug file (see here for instructions), or replace your hard disk, the modification is gone.

Fun_plug allows the user to start additional programs and tools on the NAS. A Berlin-based developer named “Fonz” created a package called “ffp” (Fonz fun_plug), which includes the script and some extra software which can be invoked by fun_plug.

Installation of fun_plug is easy and takes about 6 steps (with two optional more if you want to do some sightseeing rather than just racing over the Autobahn). These steps should be performed carefully, as they depend on typed commands and running with “root” privileges.

Contents

• Purpose, risks, and benefits
  • Responsibility
  • Benefits
  • Technical synopsis
  • Tested Devices
• Steps for installing fun_plug
  • Download
  • Option: view the fun_plug script
  • Reboot
  • Option: view ffp.log
  • Connect via telnet
  • Change root password
  • Activate SSH
  • Logging in using SSH
  • Now what?
• Notes
  • Fun_plug and user accounts

Purpose, risks, and benefits

Fun_plug is essentially a technique to stepwise turn a NAS with fixed out-of-the-box functionality into an open Linux machine on which you can install additional software packages and, if you want, learn a bit about Linux.

Responsibility

This also implies that you are (temporarily or permanently) turning a stable turnkey system into a system that Conceptronic no longer supports. This is similar to buying a notebook with Microsoft software, and installing Linux on it. The shop where you bought it can no longer help you if you claim the audio no longer works. Although there is aTutorial on how to disable and even remove fun_plug, and although the authors have tested their recipes, checked the wording and added warnings, these are advanced tools which can, if you experiment more than your own know-how can handle, give advanced problems.

Risks involved in all this are not so much damaging your hardware (shouldn’t be possible), but loss of reliability of the NAS (you bought a file server to reliably store files, didn’t you). This risk may be acceptable because the software was preintegrated and tested by competent people. But you yourself are, at the end of the day, responsible for deciding to use this.

Possibly a less obvious, but more real risk is that some kind of extensions to the NAS (e.g. adding a server) imply that you may decide to open your local network a bit to the outside world. For example, to allow others to view your holiday videos stored on the device. The out-of-the-box NAS can already have this problem (via the ftp server). The point here is that you are responsible for the security of your device and entire network. This site doesn’t even have tutorials on basic security issues like firewalls, etc. because these are all NAS independent and the tutorials would never be foolproof anyway. So when used wrongly, the NAS and firewall obviously do allow others to read more data than you intended. Or to delete your valuable data. Or to replace software by other software (chance is small, but the impact is high).

Conclusion: as the NAS is a powerful networked device, and as these tutorials can help you make it even more powerful, you are responsibility for having the basic understanding of networked security. Again, this also applies to an out-of-the-box NAS. But the more you mess with it, the more you need to apply some common sense. This is incidentally the reason why we provide some explanation on what you are doing in the tutorials, rather than just telling you what to type