[PATCH 0/3] Add O_DENY* flags to fcntl and cifs

[J. Bruce Fields]

On Sat, Dec 08, 2012 at 12:43:14AM +0400, Pavel Shilovsky wrote:
> The problem is the possibility of denial-of-service attacks here. We
> can try to prevent them by:
> 1) specifying an extra security bit on the file that indicates that
> share flags are accepted (like we have for mandatory locks now) and
> setting it for neccessary files only, or
> 2) adding a special mount option (but it it probably makes sense if
> we decided to add this support for CIFS and NFS only).

In the case of knfsd and samba exporting a common filesystem, you'd also
want to be able to enforce it on the exported filesystem.

--b.