Re: [RFC PATCH 12/12] IMA: Use the the system trusted keyrings instead of .ima_mok [ver #2]

From: Mimi Zohar
Date: Tue Mar 08 2016 - 09:38:48 EST


On Tue, 2016-03-08 at 16:14 +0200, Petko Manolov wrote:
> On 16-03-08 13:08:36, David Howells wrote:
> > Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > > Only certificates signed by a key on the system keyring were added to
> > > the IMA keyring, unless IMA_MOK_KEYRING was configured. Then, the
> > > certificate could be signed by a either a key on the system or ima_mok
> > > keyrings. To replicate this behavior, the default behavior should be to
> > > only permit certificates signed by a key on the builtin keyring, unless
> > > this new Kconfig is enabled. Only then, permit certificates signed by a
> > > key on either the builtin or secondary keyrings to be added to the IMA
> > > keyring.
> >
> > How about I change it to a choice-type item, with the following options:
> >
> > (1) No addition.
> >
> > (2) Addition restricted by built-in keyring.
> >
> > (3) Addition restricted by secondary keyring + built-in keyring.
> >
> > where the second and third options then depend on the appropriate keyrings
> > being enabled.
>
> I would suggest leaving (1) and (3). Since secondary keyring only accepts keys
> signed by certificate in the system keyring I think (2) is redundant. It adds
> extra complexity (Kconfig is vague enough already) while it doesn't increase the
> overall security by much.

I think you mean option 2 or 3, as option 1 implies not allowing any
keys to be added to the IMA keyring.

Mimi