Re: DoS with POSIX file locks?

Trond Myklebust
2006-03-22T15:56:16Z

On Wed, 2006-03-22 at 13:16 +0100, Miklos Szeredi wrote:
> > > > i concur with Trond, there's no sane way to get rid of it w/out
> > > > formalizing CLONE_FILES and locks on exec
> > >
> > > Probably there is. It would involve allocating a separate
> > > lock-owner-ID stored in files_struct but separate from it. But it's
> > > more complicated than simply not propagating locks on exec in the
> > > CLONE_FILES case.
> >
> > That doesn't solve the fundamental problem.
> >
> > You would still have to be able to tell a remote server that some locks
> > which previously belonged to one owner are being reallocated to several
> > owners.
>
> No changing of lock owner is involved, that's the whole point.

You still don't get it. For NFS/CIFS/... the locks on the server _also_
have a lock owner. The local lockowner is completely and utterly
irrelevant.

Cheers,
Trond