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Subject: Re: [PATCH V31 07/25] kexec_file: Restrict at runtime if the kernel
 is locked down
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Matthew Garrett <mjg59@google.com>
Cc:     Dave Young <dyoung@redhat.com>, James Morris <jmorris@namei.org>,
        Jiri Bohac <jbohac@suse.cz>,
        Linux API <linux-api@vger.kernel.org>,
        kexec@lists.infradead.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        David Howells <dhowells@redhat.com>,
        LSM List <linux-security-module@vger.kernel.org>,
        Andy Lutomirski <luto@kernel.org>
Date:   Mon, 24 Jun 2019 21:46:03 -0400
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On Mon, 2019-06-24 at 17:02 -0700, Matthew Garrett wrote:
> On Mon, Jun 24, 2019 at 2:27 PM Mimi Zohar <zohar@linux.ibm.com> wrote:
> 
> > I agree with Dave.  There should be a stub lockdown function to
> > prevent enforcing lockdown when it isn't enabled.
> 
> Sorry, when what isn't enabled? If no LSMs are enforcing lockdown then
> the check will return 0. The goal here is for distributions to be able
> to ship a kernel that has CONFIG_KEXEC_SIG=y, CONFIG_KEXEC_SIG_FORCE=n
> and at runtime be able to enforce a policy that requires signatures on
> kexec payloads.

Never mind, the call can't be moved earlier.