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From: Linus Torvalds <torvalds@linux-foundation.org>
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>,
	Justin Forbes <jforbes@redhat.com>,
	linux-man <linux-man@vger.kernel.org>, joeyli <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>
Subject: Re: [GIT PULL] Kernel lockdown for secure boot
Date: Tue, 3 Apr 2018 16:39:48 -0700	[thread overview]
Message-ID: <CA+55aFx9u-O81MwSq8zpb+MKaWYjYvtEcFu1NLP1_s63ED6_3Q@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFyWNok1K-Jo3TQAXGXHvFOTvuOb-Hw977B9RGjBa7prrg@mail.gmail.com>

On Tue, Apr 3, 2018 at 4:26 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Magically changing kernel behavior depending on some subtle and often
> unintentional bootup behavior detail is completely idiotic.

Another way of looking at this: if lockdown is a good idea to enable
when you booted using secure boot, then why isn't it a good idea when
you *didn't* boot using secure boot?

That's the flip side of this whole argument.

People who boot without secure boot may be wanting all the same
protections. Maybe you have to disable it when you build your own
kernel, for example. Does that suddenly mean that lockdown is now a
bad idea?

And if it does, explain it. Explain why it's a bad idea to enable
without secure boot, but is a good idea to enable *with* secure boot.

In other words: explain the tie-in.

Because I really don't see it. All I see is illogical blathering that
tries to conflate issues that have nothing to do with each other.

Please explain to me why a distro or a user would want lockdown to be
disabled just because the user didn't use secure boot, but suddenly if
it's booted on another machine, it's not just a good idea, but
mandatory in your world view?

Honestly, if I were a distro maintainer, the *last* thing I'd want is
the kernel to act fundamentally differently in some security context
depending on some random bootup condition.

              Linus

  reply	other threads:[~2018-04-03 23:39 UTC|newest]

Thread overview: 126+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-30 23:29 [GIT PULL] Kernel lockdown for secure boot David Howells
2018-03-31  0:46 ` James Morris
2018-04-03  0:37   ` Andy Lutomirski
2018-04-03  0:59     ` Kees Cook
2018-04-03  1:47       ` Andy Lutomirski
2018-04-03  7:06   ` David Howells
2018-04-03 15:11     ` Andy Lutomirski
2018-04-03 15:41       ` Alexei Starovoitov
2018-04-03 16:26         ` Andy Lutomirski
2018-04-03 16:29       ` Matthew Garrett
2018-04-03 16:45         ` Andy Lutomirski
2018-04-03 18:45           ` Kees Cook
2018-04-03 19:01             ` Andy Lutomirski
2018-04-03 19:07               ` Kees Cook
2018-04-03 19:29           ` Matthew Garrett
2018-04-03 21:51             ` Andy Lutomirski
2018-04-04 18:42               ` Peter Jones
2018-04-04 20:01                 ` Thomas Gleixner
2018-04-04 20:18                   ` Matthew Garrett
2018-04-05 18:47                 ` Andy Lutomirski
2018-04-06  4:42                 ` Peter Dolding
2018-04-03 17:16         ` David Howells
2018-04-03 19:01           ` Andy Lutomirski
2018-04-03 19:49           ` David Howells
2018-04-03 21:58             ` Andy Lutomirski
2018-04-03 22:32             ` David Howells
2018-04-03 22:39               ` Andy Lutomirski
2018-04-03 22:46                 ` Linus Torvalds
2018-04-03 22:51                   ` Matthew Garrett
2018-04-03 22:53                     ` Andy Lutomirski
2018-04-03 23:08                       ` Justin Forbes
2018-04-03 23:09                       ` Matthew Garrett
2018-04-03 23:08                     ` Linus Torvalds
2018-04-03 23:10                       ` Linus Torvalds
2018-04-03 23:17                       ` Matthew Garrett
2018-04-03 23:26                         ` Linus Torvalds
2018-04-03 23:39                           ` Linus Torvalds [this message]
2018-04-03 23:47                             ` Matthew Garrett
2018-04-04  0:02                               ` Linus Torvalds
2018-04-04  0:04                                 ` Matthew Garrett
2018-04-04  0:08                                   ` Linus Torvalds
2018-04-04  0:12                                     ` Matthew Garrett
2018-04-05 14:58                                       ` Alan Cox
2018-04-04  0:22                                   ` David Howells
2018-04-05 17:59                                   ` Alan Cox
2018-04-05 18:03                                     ` Matthew Garrett
2018-04-03 23:45                           ` Matthew Garrett
2018-04-03 23:55                             ` Linus Torvalds
2018-04-03 23:59                               ` Matthew Garrett
2018-04-04  0:06                                 ` Linus Torvalds
2018-04-04  0:10                                   ` Matthew Garrett
2018-04-04  0:15                                     ` Linus Torvalds
2018-04-04  0:16                                       ` Matthew Garrett
2018-04-04  0:18                                         ` Andy Lutomirski
2018-04-04  0:19                                           ` Matthew Garrett
2018-04-04  9:04                                             ` Greg Kroah-Hartman
2018-04-04  0:25                                         ` Linus Torvalds
2018-04-04  0:33                                           ` Linus Torvalds
2018-04-04  0:46                                             ` Matthew Garrett
2018-04-04  0:56                                               ` Linus Torvalds
2018-04-04  1:13                                                 ` Matthew Garrett
2018-04-04  1:43                                                   ` Linus Torvalds
2018-04-04  4:30                                                     ` Matthew Garrett
2018-04-04 12:57                                                       ` Theodore Y. Ts'o
2018-04-04 13:02                                                         ` Greg Kroah-Hartman
2018-04-04 13:34                                                           ` Theodore Y. Ts'o
2018-04-04 13:57                                                             ` Greg Kroah-Hartman
2018-04-04 13:29                                                         ` Mike Galbraith
2018-04-04 16:20                                                         ` Matthew Garrett
2018-04-08 22:00                                                         ` Pavel Machek
2018-04-04 13:33                                                       ` David Howells
2018-04-04 13:52                                                         ` Theodore Y. Ts'o
2018-04-04 16:22                                                           ` Matthew Garrett
2018-04-04 16:39                                                             ` Andy Lutomirski
2018-04-04 16:42                                                               ` Matthew Garrett
2018-04-04 16:46                                                               ` Justin Forbes
2018-04-05  0:05                                                             ` Peter Dolding
2018-04-05  0:20                                                               ` Matthew Garrett
2018-04-04 13:57                                                         ` David Howells
2018-04-04 16:09                                                       ` Linus Torvalds
2018-04-04 16:17                                                         ` Matthew Garrett
2018-04-04  6:56                                                   ` Peter Dolding
2018-04-04 16:26                                                     ` Matthew Garrett
2018-04-05  1:28                                                       ` Peter Dolding
2018-04-04  1:30                                                 ` Justin Forbes
2018-04-04  1:58                                                   ` Linus Torvalds
2018-04-04  1:36                                                 ` Justin Forbes
2018-04-04  0:17                                   ` Jann Horn
2018-04-04  0:23                                     ` Andy Lutomirski
2018-04-04  8:05                                     ` David Howells
2018-04-04 14:35                                       ` Andy Lutomirski
2018-04-04 14:44                                       ` David Howells
2018-04-04 15:43                                       ` Eric W. Biederman
2018-04-03 23:56                         ` David Howells
2018-04-03 23:58                           ` Linus Torvalds
2018-04-03 23:39                 ` David Howells
2018-04-03 23:48                   ` Andy Lutomirski
2018-04-08  8:23                   ` Pavel Machek
2018-04-03 23:12               ` David Howells
2018-04-03 23:27                 ` Linus Torvalds
2018-04-03 23:42                 ` Andy Lutomirski
2018-04-03 20:53         ` Linus Torvalds
2018-04-03 20:54           ` Matthew Garrett
2018-04-03 21:01             ` Linus Torvalds
2018-04-03 21:08               ` Matthew Garrett
2018-04-03 21:21                 ` Al Viro
2018-04-03 21:37                   ` Matthew Garrett
2018-04-03 21:26                 ` Linus Torvalds
2018-04-03 21:32                   ` Matthew Garrett
2018-04-08  8:10                 ` Pavel Machek
2018-03-31 10:20 ` David Howells
2018-04-03 13:25   ` Ard Biesheuvel
2018-04-03 21:48     ` James Morris
2018-04-05 17:53     ` Alan Cox
2018-11-21 12:05 ` [PATCH next-lockdown 0/1] debugfs EPERM fix for 'Kernel lockdown for secure boot' patch series Vasily Gorbik
2018-11-21 12:05   ` [PATCH next-lockdown 1/1] debugfs: avoid EPERM when no open file operation defined Vasily Gorbik
  -- strict thread matches above, loose matches on Subject: below --
2018-04-04  2:34 [GIT PULL] Kernel lockdown for secure boot Alexei Starovoitov
2018-04-04  4:31 ` Matthew Garrett
2018-04-08  7:44   ` joeyli
2018-04-08  8:07 ` joeyli
2018-04-09  3:40   ` Alexei Starovoitov
2018-04-09  8:14     ` Daniel Borkmann
2018-04-09 13:55     ` joeyli
2017-10-26 16:37 David Howells
2017-10-26 18:22 ` Mimi Zohar
2017-10-26 19:20 ` James Morris

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