Can't Write to External Drive From User Account

[Lennart Sorensen]

On Tue, Feb 27, 2007 at 08:07:57PM -0500, Glen Strom wrote:
> I thought I must have forgotten something. It is an ext3 file system,
> and I was changing the permissions without first mounting the drive.
> After I mounted it, the change worked, but not without an unexpected
> side effect (unexpected by me, anyway).
> 
> When I first changed the permissions, I removed the executable flag
> because the drive is for backup purposes only:
> 
> rw- rw- r-- root disk
> 
> I could not access /mnt/usbdrive1 from my user account. It would only
> work when I included the executable flag for both root and group.
> 
> rwx rwx r-- root disk
> 
> I don't know why that is, but anyway, everything seems to work ok now.

The execute bit is used to control directory access on directories.  No
execute means you can't look up filenames in the directory, although you
can still access files if you know their names already.

A directory needs read and execute access for a user to have any kind of
normal sane access to it.  You can mount with noexec instead if that is
what you want, since that prevents people running binaries from there,
but doesn't prevent access to directories.

--
Len Sorensen
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