NAS Troubleshooting via the Back Door
I recently bought a NAS enclosure with 1TB of storage for my humble home LAN. While I eventually managed to identify the manufacturer as a firm called ‘Sumvision’, the packaging didn’t make this obvious and upon opening it up I got that distinct and familiar feeling of ‘you’re on your own from here’. Of course, none of this came as a surprise (given the price I paid) and I was pleasantly surprised to find a fresh set of firmware available on the website (version 2.4.4-Jul 8 2008). What did upset me, though, was the awful performance I experienced when using it over my wireless connection. A short Google later it became apparent that this is a common problem with NAS devices, caused by the typically higher packet-loss experienced on wireless connections. Briefly put, SAMBA (and NFS) transmission units often default to 8192 bytes or more, whereas IPv4 networks without the relatively new jumbo frame support will fragment anything above the 1500-or-so-byte MTU. The suggested fix, for SAMBA devices such as mine, is to tweak this value in the server’s smb.conf:
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE SO_RCVBUF=1024 SO_SNDBUF=1024
Alas, I found no obvious way to modify these values in the enclosure’s web interface. Furthermore, extracting the hard-drive and mounting it locally proved that it is used for content storage only – the OS sits on a ROM, away from the user’s grubby fingers. And so I was out of luck and was at the point of giving up, until curiosity got the better of me. Taking a look at the ‘shares’ page of the admin interface it was pretty clear that this thing was running a Unix-based OS (disclosing local paths such as ‘/mnt/C/Media/Music’), and if their implementation was as flaky as their design there may be another way in.
So I tried what any hacker would have done faced with this input field, and tried to traverse the device-local path using some ‘../’s.
Now I won’t pretend that it was big, clever or original, but to my surprise it worked. Browsing to ‘\\nas\Root’ from my computer landed me right in the device’s root, with admin read/write privileges. For those wondering, the OS is BusyBox.
And the rest is history. A couple of words of warning to anybody planning on doing the same:
- In order to access this root share, the device obviously needs to boot and mount successfully. As such I wouldn’t be the slightest bit surprised if any undue alterations to the OS or its configuration result in the device being rendered permanently unusable. I never did brick mine and so haven’t confirmed this, but be very careful what you touch.
- /config/smb.conf is presumably kept open at all times, and so you’ll likely have trouble saving to it. I found that saving as a different file and then renaming them around works fine. Be aware that there is very little excess space to play with (I suspect it’s mounted as a ramdrive).
- The smb.conf, at least, seems quite volatile, in that any changes via the web interface result in the [global] parameters being reset to their defaults. I have observed the alterations to persist across reboots but couldn’t offer a comprehensive list of actions that result in it being wiped clean, so don’t be surprised if you find that your fixes disappear when you’re not looking.
I’ve found also a newer firmware revision, the 2.4.5 available at: http://www.envizage.com/g/36586/downloads.html
However both the 2.4.4 and the 2.4.5 doesn’t seem to support (if you look at the interface) the NFS protocol while it was available with the default 2.2 (but that I’ve never tried since it had some issues with my 1Tb HDD and with the DHCP).
Thanks to the discoveries by NutTom, I’ve been able to keep these changes between reboots… If you want I can upload my image, but I figure you can easily build your own using these scripts to split the .bin:
#!/bin/bash
dd if=$1 of=”config” ibs=1k count=64
dd if=$1 of=”kernel” ibs=1k count=960 skip=64
dd if=$1 of=”root” ibs=1k count=896 skip=1024
dd if=$1 of=”www.gz” ibs=1k count=64 skip=1920
dd if=$1 of=”extra” ibs=1k skip=1984
and join it:
#!/bin/bash
cat config kernel root http://www.gz extra > $1
Hi can you tell me how to mount those files for edition??
mknod /tmp/mtdblock0 b 31 0
losetup /dev/loop0 rootfs.jffs2
echo “/dev/loop0,128KiB” > /sys/module/block2mtd/parameters/block2mtd
mount -t jffs2 /tmp/mtdblock0 /media/jffs2
Hi
How you get acess in the terminal?
I´m having problem with USHARE upnp mediacenter with Playstation 3. I´d like to upgrade the ushare, mount the device with write/read but I think that is not possible in this way.
With terminal, I can try it.
Someone has the same problem with MediaCenter X Playstation 3 in the 650 enclosure driver?
To acces terminal you have to solder max232 circuit to the m_bord. I have done it but all filesystem is read-only, barring some directories, but still not very usable.
The only way to edit filesystem is by editing flash image.
I managed that as well but something strange happens after rebuilding image with mk.jffs2, i’m getting 408kb free space in the image and some files look like they lost their attributes, so i didn’t flash modified image yet. I need to be sure i won’t brick the device with this flash.
Hi Arti,
Thanks.
I´m reading your posts in the other forum, but I´m not a linux specialist.
Do you have any problem with Media Center of the NAS 650? It´s terrible bad.
Also, I´ve asked to support at
http://www.szwlxkj.com/EN/Server.asp
and no one answered me.
Thanks
Como que faço para resolver o desempenho da rede que fica em torno de 120 kb por segundo?
does anyone found a firmware > 2.5.0 for this NAS. It seems to have some problems with BitTorrent directories.
does anyone found a firmware > 2.5.0 for this NAS? It seems to have some problems with BitTorrent directories.
Hi Can anybody provide valid link for the new firmware ?
Hi,
I had the stupidity to press the “update” on this thing hoping that it will open a web link etc, but NO. Now the software is completely erased and I can’t use the hardware at all. I will appreciate if somebody could help me, Thank you!
Do you have the “Nas 650″ ‘s fireware?
and send mail to me.
thanks.
this page can’t open:
http://www.envizage.com/g/36586/downloads.html