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From:   Matthew Garrett <mjg59@google.com>
Date:   Wed, 04 Apr 2018 00:16:46 +0000
Message-ID: <CACdnJuv-VpdhjEe1cMysdHb6Oy67jQqg-_TVHbUrOfH9GmCVvg@mail.gmail.com>
Subject: Re: [GIT PULL] Kernel lockdown for secure boot
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     luto@kernel.org, David Howells <dhowells@redhat.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>, jmorris@namei.org,
        Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        jforbes@redhat.com, linux-man@vger.kernel.org, jlee@suse.com,
        LSM List <linux-security-module@vger.kernel.org>,
        linux-api@vger.kernel.org, Kees Cook <keescook@chromium.org>,
        linux-efi <linux-efi@vger.kernel.org>
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On Tue, Apr 3, 2018 at 5:15 PM Linus Torvalds
<torvalds@linux-foundation.org>
wrote:
> On Tue, Apr 3, 2018 at 5:10 PM, Matthew Garrett <mjg59@google.com> wrote:
> >
> >> Exactly like EVERY OTHER KERNEL CONFIG OPTION.
> >
> > So your argument is that we should make the user experience worse?
Without
> > some sort of verified boot mechanism, lockdown is just security theater.
> > There's no good reason to enable it unless you have some mechanism for
> > verifying that you booted something you trust.

> Wow. Way to snip the rest of the email where I told you what the
> solution was. Let me repeat it here, since you so conveniently missed
> it and deleted it:

I ignored it because it's not a viable option. Part of the patchset
disables various kernel command line options. If there's a kernel command
line option that disables the patchset then it's pointless.