Re: [PATCH 07/27] kexec_file: Disable at runtime if securelevel has been set

[Mimi Zohar]

[Cc'ing Matthew Garrett]

On Thu, 2017-10-26 at 16:02 +0100, David Howells wrote:
> joeyli <jlee@xxxxxxxx> wrote:
> 
> > +	if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) &&
> > +	    !is_ima_appraise_enabled() &&
> > +	    kernel_is_locked_down("kexec of unsigned images"))
> 
> This doesn't seem right.  It seems that you can then kexec unsigned images
> into a locked-down kernel if IMA appraise is enabled.

Huh?! ÂWith the "secure_boot" policy enabled on the boot command line,
IMA-appraisal would verify the kexec kernel image, firmware, kernel
modules, and custom IMA policy signatures. ÂWith the "ima: require
secure_boot rules in lockdown mode" patch, the "lockdown" mode would
enable IMA-appraisal's secure_boot policy, without requiring the boot
command line option. ÂIt would also add the secure_boot rules to the
custom policy, so that if the builtin policy is replaced with a custom
policy, the "secure_boot" policy would still be enforced.

Other patches in this patch series need to be updated as well to check
if IMA-appraisal is enabled.

Mimi