Re: IMA: kernel reading files opened with O_DIRECT

Pavel Machek
2014-07-15T13:03:12Z

On Sat 2014-07-12 01:22:04, Dmitry Kasatkin wrote:
> On 11 July 2014 23:10, Pavel Machek <pavel@ucw.cz> wrote:
> > On Wed 2014-07-02 11:40:50, Christoph Hellwig wrote:
> >> On Wed, Jul 02, 2014 at 11:55:41AM -0400, Jeff Moyer wrote:
> >> > It's acceptable.
> >>
> >> It's not because it will then also affect other reads going on at the
> >> same time.
> >>
> >> The whole concept of ima is just broken, and if you want to do these
> >> sort of verification they need to happen inside the filesystem and not
> >> above it.
> >
> > ...and doing it at filesystem layer would also permit verification of
> > per-block (64KB? 1MB?) hashes.
>
> Please design one single and the best universal filesystem which
> does it.

Given the overhead whole-file hashing has, you don't need single best
operating system. All you need it either ext4 or btrfs.. depending on
when you want it in production.

Pavel

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