Re: Bad ext3/nfs DoS bug

Christoph Hellwig
2006-07-27T19:13:34Z

On Thu, Jul 27, 2006 at 01:32:43PM -0500, Eric Sandeen wrote:
> Neil Brown wrote:
> >On Wednesday July 26, sandeen@sandeen.net wrote:
>
> >>Hm, with this, ext3.ko has a new dependency on exportfs.ko. Is that
> >>desirable/acceptable?
> >
> >Drat, you're right.
> >No, I don't think that is what we want.
> >I'll do it differently in a day or so.
>
> Would moving export_iget into fs/inode.c & exporting it from there be a
> reasonable way to go? At least ext2 & ext3 both have this need (prevent
> nfs access to special inodes) so putting the bulk of what they need for
> get_dentry (i.e. export_iget) somewhere common seems like a decent
> option to me.

Nope. The right fix is to not make ext2/3 rely on export_iget at all. Please
implement the proper export_operations instead, similar to e.g. xfs.

export_iget is a horrible layering violation that needs to go away long-term,
not move into core code.