Re: Bad ext3/nfs DoS bug

Neil Brown
2006-07-28T00:35:41Z

On Thursday July 27, hch@infradead.org wrote:
> On Thu, Jul 27, 2006 at 01:32:43PM -0500, Eric Sandeen wrote:
> > Neil Brown wrote:
> > >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.

Agreed.
I've just submitted revised patches. They effectively open-code
export_iget in a local implemention of the get_dentry
export_operation.

This should give the problem with no unpleasant exports or layering
issues.

NeilBrown