I've recently purchased a SanDisk Cruzer Micro USB drive for use with my Redhat 9 distribution. As root, I've been successful in mounting the device with:

mkdir /mnt/cruzer
mount /dev/sda1 /mnt/cruzer

I can then cd to the drive, read and write stuff with no troubles - again, as long as I'm root. No problems so far.

BUT - I am having troubles as a regular user (joe). joe can cd to the drive, read files from the drive, but he can't write anything. joe always gets a "permissiong denied".

OK, so I figure file permissions are the cause. Back at root I display the permissions:

drwxr-xr-x 2 root root 4096 Feb 20 2004 cdrom
drwxr-xr-x 8 root root 16384 Dec 31 1969 cruzer
drwxr-xr-x 2 root root 4096 Feb 20 2004 floppy

and I try to change them:

chmod 777 cruzer

But I get :

chmod: changing permissions of `cruzer' (requested: 0777, actual: 0755): Operation not permitted

The same is true if I attempt to change any of the permissions of files already on cruzer (placed there earlier by root).

Hmm - my first question arrises - Is this because the file system on the jump drive is vfat, and doesn't contain any fields for file permission values?

OK, so I read around a bit and discover that entries in fstab are needed. I modified fstab:

/dev/sda1 /mnt/cruzer auto user,rw,noauto 0 0

I then unmounted and remounted cruzer and got the same results: Root can do it all, but joe can't write anything. I also tried:

/dev/sda1 /mnt/cruzer vfat user,rw,noauto 0 0

(no restarts in between the changes to fstab, but I shouldn't have to, right?)

I also tried to mount cruzer from joe, but 'only root can do that'.

So, I'm at a loss. What can I do differently to allow joe to write to the cruzer?

if you want joe to be able to access it the same way root can, then when you mount it add the option uid=joe

if you want user joeandfriends to be able to access it as well, do gid=joeandfriends

Too simple!

Thank you, FliesLikeaBrick for the quick and complete reply.

I was unaware of the -o uid option of the mount command. I tried it, it works, I'm moving on.....

Thanks again.

yay my first time really helping someone :P

Thanks; I have the same situation


But, I mounted my USB key file system in my home directory with:

$ sudo mount -o uid=pascalv -o gid=pascalv /dev/sda1 ~/usb


and still cannot change the permissions:

$ chmod 777 ~/usb
$ ls -l

gets
drwxr-xr-x 2 pascalv pascalv 16888 1970-01-01 01:00 usb

and not
drwxrwxrwx


Would somebody have an explanation?

The issue may be that your USB is formatted as FAT16 or FAT32, which can't recognize POSIX file permissions. Try mounting it like this
The umask will cause the device to be mounted with 777 permissions. Good luck with it