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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 3 Apr 2018 13:53:06 -0700
Message-ID: <CA+55aFy5EPxAyqyGGaYUUyakuLbjXHiseWCkz-oNdo=Y-878tg@mail.gmail.com>
Subject: Re: [GIT PULL] Kernel lockdown for secure boot
To:     Matthew Garrett <mjg59@google.com>
Cc:     Andrew Lutomirski <luto@kernel.org>,
        David Howells <dhowells@redhat.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        James Morris <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 <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 9:29 AM, Matthew Garrett <mjg59@google.com> wrote:
> On Tue, Apr 3, 2018 at 8:11 AM Andy Lutomirski <luto@kernel.org> wrote:
>> Can you explain that much more clearly?  I'm asking why booting via
>> UEFI Secure Boot should enable lockdown, and I don't see what this has
>> to do with kexec.  And "someone blacklist[ing] your key in the
>> bootloader" sounds like a political issue, not a technical issue.
>
> A kernel that allows users arbitrary access to ring 0 is just an
> overfeatured bootloader. Why would you want secure boot in that case?

.. maybe you don't *want* secure boot, but it's been pushed in your
face by people with an agenda?

Seriously.

                  Linus