[PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set

[Mimi Zohar]

On Fri, 2017-04-07 at 08:09 +0100, David Howells wrote:
> Mimi Zohar <zohar at linux.vnet.ibm.com> wrote:
> 
> > > > +	if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && kernel_is_locked_down())
> > > > +		return -EPERM;
> > > > +
> > > >  
> > 
> > IMA can be used to verify file signatures too, based on the LSM hooks
> > in  kernel_read_file_from_fd().  CONFIG_KEXEC_VERIFY_SIG should not be
> > required.
> 
> Okay, fair enough.  I can stick in an OR with an IS_ENABLED on some IMA
> symbol.  CONFIG_IMA_KEXEC maybe?  And also require IMA be enabled?

Not quite, since as Dave pointed out, IMA is policy driven.  As a
policy is installed, we could set a flag.

Mimi