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From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, Matthew Garrett <mjg59@google.com>,
	Andrew Lutomirski <luto@kernel.org>,
	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: Wed, 04 Apr 2018 01:22:27 +0100	[thread overview]
Message-ID: <11962.1522801347@warthog.procyon.org.uk> (raw)
In-Reply-To: <CA+55aFzH6doC2F1xBitPRwTZtbiCO_mX+QVcJ8HQCdsdD3Vmpg@mail.gmail.com>

Linus Torvalds <torvalds@linux-foundation.org> wrote:

> ...  use the kernel command line to disable things.

An attacker could then modify grub.cfg, say, and cause a reboot (or wait for
the next reboot) to disable lockdown:-/

And whilst we could also distribute a non-locked-down variant of the kernel as
an alternative, the attacker could install and boot that instead since we
can't lock package installation down very easily since it doesn't impinge
directly on the running kernel.

Unfortunately, it's hard to come up with a disablement mechanism in the kernel
that an attacker can't also make use of:-/

David

  parent reply	other threads:[~2018-04-04  0:22 UTC|newest]

Thread overview: 112+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4136.1522452584@warthog.procyon.org.uk>
     [not found] ` <alpine.LRH.2.21.1803311145180.7769@namei.org>
2018-04-03  0:37   ` [GIT PULL] Kernel lockdown for secure boot 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
     [not found]           ` <CAGXu5j+CyVXEvsMarJjBwaNh7poVZtmit5PGmQM9rKKqZPqVXg@mail.gmail.com>
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 23:09                       ` 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
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 [this message]
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  1:36                                                 ` Justin Forbes
     [not found]                                                 ` <CAFbkSA0ursG3RGWU19LQiD6u30h5V=Aqj3oVyHQCiX6MLopYUg@mail.gmail.com>
2018-04-04  1:58                                                   ` Linus Torvalds
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
2018-04-04  2:34 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

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