Chris Wedgwood wrote:
> On Thu, Jun 01, 2000 at 04:03:15PM -0700, H. Peter Anvin wrote:
[...]
> mount -t bind /home/user /home/user/again
[...]
> No it won't. /home/user/again is be empty. Try it.
I had a quick look at the code but couldn't quite figure out how
it accomplishes this, and I don't have any system running a kernel
recent enough to experiment, so I have a few perhaps silly questions:
- shouldn't mount simply return an error in this case ?
- what happens if I try to create things in /home/user/again ?
- does this mechanism rule out all cases where a device can be mounted
on a directory of the file system on that device ?
Restricting -t bind seems useful to me, unless there were already means
for a user to make nasty surprises (a la proc, NFS, devfs, etc.) appear
in their directories (except -o user, of course). E.g. an administrator
could simply backup everything underneath /export, without looking at
FS boundaries - until now. Maybe this is finally a case for MS_NOSUB.
- Werner
-- _________________________________________________________________________ / Werner Almesberger, ICA, EPFL, CH werner.almesberger@ica.epfl.ch / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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