Re: [PATCH v2] ima: add a new CONFIG for loading arch-specific policies

[Mimi Zohar <zohar@linux.ibm.com>]

On Tue, 2020-03-03 at 23:43 -0800, James Bottomley wrote:
> On Tue, 2020-03-03 at 21:33 -0500, Nayna Jain wrote:

> > diff --git a/security/integrity/ima/Kconfig
> > b/security/integrity/ima/Kconfig
> > index 3f3ee4e2eb0d..d17972aa413a 100644
> > --- a/security/integrity/ima/Kconfig
> > +++ b/security/integrity/ima/Kconfig
> > @@ -327,3 +327,12 @@ config IMA_QUEUE_EARLY_BOOT_KEYS
> >  	depends on IMA_MEASURE_ASYMMETRIC_KEYS
> >  	depends on SYSTEM_TRUSTED_KEYRING
> >  	default y
> > +
> > +config IMA_SECURE_AND_OR_TRUSTED_BOOT
> > +	bool
> > +	depends on IMA
> > +	depends on IMA_ARCH_POLICY
> > +	default n
> 
> You can't do this: a symbol designed to be selected can't depend on
> other symbols because Kconfig doesn't see the dependencies during
> select.  We even have a doc for this now:
> 
> Documentation/kbuild/Kconfig.select-break

The document is discussing a circular dependency, where C selects B.
 IMA_SECURE_AND_OR_TRUSTED_BOOT is not selecting anything, but is
being selected.  All of the Kconfig's are now dependent on
IMA_ARCH_POLICY being enabled before selecting
IMA_SECURE_AND_OR_TRUSTED_BOOT.

As Ard pointed out, both IMA and IMA_ARCH_POLICY are not needed, as
IMA_ARCH_POLICY is already dependent on IMA.

Mimi