Wednesday, May 23, 2012

NAS error - You require permission from UNIX

This is an error you will see in Windows, usually followed by a particular user (either ROOT or NOBODY), and the type of action you were trying to take (delete, edit, save) on a file. You would get this error when attempting such an operation against a personal NAS, a Network Attached Storage server, which is basically a device on your home network with hard drives you can access over the network through Windows shares (CIFS) or FTP.

I ran across this with my iOmega iConnect. This is a relatively cheap yet cool little device with 4 usb ports on it. You pop it on your wifi or wired network and plug in some external drives or usb thumb drives even, and then it serves all that storage up. It has some performance foibles, and the security can be a little hairy, but for the most part it works great.

Until I ran into this error. For one of the computers accessing files on one of the drives, it wasn’t able to edit, move or delete certain files.

When I googled the error, I found out that this problem is very common, and is not limited to my particular personal NAS, but occurs with many different ones.

It’s pretty well known that these little network devices tend to have Unix or Linux at the core. There are tons of embeddable distros that are very mature and stable. Thus the error makes perfect sense, and we can guess that Windows and Unix are having a misunderstanding about file permissions, which considering they have different file permission systems, is not surprising.

There was one post I found that went a little deeper into what the particular incompatibility is:

http://forums.seagate.com/t5/BlackArmor-NAS-Network-Storage/File-Access-Denied-quot-You-require-permission-from-UNIX-root-to/td-p/95048

Here’s a quote from the relevant portion, “ it has to do the EXT file system the NAS uses and inherent limitations, the fact that these files are hidden to Unix “ … ”If you gained root access via Linux and mounted the EXT partition then you probably could do this”

So all that being said, none of the fixes or workarounds mentioned in the various posts, including running “ATTRIB Z:\*.* -a -r -s -h -i /S /D” on the whole drive, worked for me. What did eventually work, was to pull the drive from the NAS and mount it to a pc locally via USB, and to move all the files out of what were essentially old system folders (My Documents, My Music, My Pictures, etc.) into new standard folders. Then a second step that was required, was to go into Windows on the machine that was having problems with the files, and get rid of all previous relevant cached share connections ( http://superuser.com/questions/63190/windows-7-cached-network-share-credentials ), and reboot and make a brand new share connection.