Re: [PATCH v5 0/5] Lazy flush for the auth session

[Mimi Zohar]

On Mon, 2024-10-14 at 15:34 +0300, Jarkko Sakkinen wrote:
> On Mon, 2024-10-14 at 07:45 -0400, Mimi Zohar wrote:
> > > > For server/IMA use case I'll add a boot parameter it can be
> > > > either on or off by default, I will state that in the commit
> > > > message and we'll go from there.
> > 
> > Sounds good.
> 
> But only after this patch set lands. I gave this a thought and since
> this patch set is specifically for a specific Bugzilla bug that it
> closes, I have no interest to increase its scope.

Prior to your performance improvement patch set it took >10 minutes to boot,
when it succeeded booting.  Now on Fedora 40 with "ima_policy=tcb" on the boot
command line, it's taking ~3 minutes to boot.  Do you really think that is
acceptable?!

> > 
> > > 
> > > Up until legit fixes are place distributors can easily disable
> > > the feature. It would be worse if TCG_TPM2_HMAC did not exist.
> > > 
> > > So I think it is better to focus on doing right things right,
> > > since the feature itself is useful objectively, and make sure
> > > that those fixes bring the wanted results.

The right thing would have been to listen to my concerns when this was initially
being discussed.  The right thing wasn't enabling TCG_TPM2_HMAC by default.

> > 
> > Are you backtracking on having a boot parameter here specifically to
> > turn on/off
> > HMAC encryption for IMA?
> 
> I'm not really sure yet but obviously any change goes through review.
> 
> Also fastest route is to send your own RFC's to IMA specific issue.
> For me it will take some time (post this patch set).

Done.  The patch applies cleanly with/without the TPM performance improvement
patch set.
https://lore.kernel.org/linux-integrity/20241015193916.59964-1-zohar@xxxxxxxxxxxxx/

Mimi