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From:   David Howells <dhowells@redhat.com>
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To:     Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc:     dhowells@redhat.com, linux-security-module@vger.kernel.org,
        gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org,
        matthew.garrett@nebula.com, gregkh@linuxfoundation.org,
        linux-kernel@vger.kernel.org, jforbes@redhat.com
Subject: Re: [PATCH 03/27] Enforce module signatures if the kernel is locked down
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Date:   Thu, 02 Nov 2017 22:01:07 +0000
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Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:

> Right, it would never get here if the IMA signature verification
> fails.  If sig_enforce is not enabled, then it will also work.  So the
> only case is if sig_enforced is enabled and there is no key.
> 
> eg.
>          else if (can_do_ima_check && is_ima_appraise_enabled())
>                 err = 0;

I'm not sure where you want to put that, but I can't just do this:

	/* Not having a signature is only an error if we're strict. */
	if (err == -ENOKEY && !sig_enforce &&
	    (!can_do_ima_check || !is_ima_appraise_enabled()) &&
	    !kernel_is_locked_down("Loading of unsigned modules"))
		err = 0;
	else if (can_do_ima_check && is_ima_appraise_enabled())
		err = 0;

because that'll print out a message in lockdown mode saying that you're not
allowed to do that and then maybe do it anyway.

David

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