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From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: David Howells <dhowells@redhat.com>
Cc: Matthew Garrett <mjg59@google.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	luto@kernel.org, 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>
Subject: Re: [GIT PULL] Kernel lockdown for secure boot
Date: Wed, 4 Apr 2018 09:52:51 -0400	[thread overview]
Message-ID: <20180404135251.GD16242@thunk.org> (raw)
In-Reply-To: <24353.1522848817@warthog.procyon.org.uk>

On Wed, Apr 04, 2018 at 02:33:37PM +0100, David Howells wrote:
> Theodore Y. Ts'o <tytso@mit.edu> wrote:
> 
> > Whoa.  Why doesn't lockdown prevent kexec?  Put another away, why
> > isn't this a problem for people who are fearful that Linux could be
> > used as part of a Windows boot virus in a Secure UEFI context?
> 
> Lockdown mode restricts kexec to booting an authorised image (where the
> authorisation may be by signature or by IMA).

If that's true, then Matthew's assertion that lockdown w/o secure boot
is insecure goes away, no?

							- Ted

WARNING: multiple messages have this Message-ID (diff)
From: tytso@mit.edu (Theodore Y. Ts'o)
To: linux-security-module@vger.kernel.org
Subject: [GIT PULL] Kernel lockdown for secure boot
Date: Wed, 4 Apr 2018 09:52:51 -0400	[thread overview]
Message-ID: <20180404135251.GD16242@thunk.org> (raw)
In-Reply-To: <24353.1522848817@warthog.procyon.org.uk>

On Wed, Apr 04, 2018 at 02:33:37PM +0100, David Howells wrote:
> Theodore Y. Ts'o <tytso@mit.edu> wrote:
> 
> > Whoa.  Why doesn't lockdown prevent kexec?  Put another away, why
> > isn't this a problem for people who are fearful that Linux could be
> > used as part of a Windows boot virus in a Secure UEFI context?
> 
> Lockdown mode restricts kexec to booting an authorised image (where the
> authorisation may be by signature or by IMA).

If that's true, then Matthew's assertion that lockdown w/o secure boot
is insecure goes away, no?

							- Ted
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  reply	other threads:[~2018-04-04 13:52 UTC|newest]

Thread overview: 252+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-30 23:29 [GIT PULL] Kernel lockdown for secure boot David Howells
2018-03-30 23:29 ` David Howells
2018-03-31  0:46 ` James Morris
2018-03-31  0:46   ` James Morris
2018-03-31 10:20   ` David Howells
2018-03-31 10:20     ` David Howells
2018-04-03 13:25     ` Ard Biesheuvel
2018-04-03 13:25       ` Ard Biesheuvel
2018-04-03 21:48       ` James Morris
2018-04-03 21:48         ` James Morris
2018-04-05 17:53       ` Alan Cox
2018-04-05 17:53         ` Alan Cox
2018-04-03  0:37   ` Andy Lutomirski
2018-04-03  0:37     ` Andy Lutomirski
2018-04-03  0:59     ` Kees Cook
2018-04-03  0:59       ` Kees Cook
2018-04-03  1:47       ` Andy Lutomirski
2018-04-03  1:47         ` Andy Lutomirski
2018-04-03  7:06     ` David Howells
2018-04-03  7:06       ` David Howells
2018-04-03 15:11       ` Andy Lutomirski
2018-04-03 15:11         ` Andy Lutomirski
2018-04-03 15:41         ` Alexei Starovoitov
2018-04-03 15:41           ` Alexei Starovoitov
2018-04-03 16:26           ` Andy Lutomirski
2018-04-03 16:26             ` Andy Lutomirski
2018-04-03 16:29         ` Matthew Garrett
2018-04-03 16:29           ` Matthew Garrett
2018-04-03 16:45           ` Andy Lutomirski
2018-04-03 16:45             ` Andy Lutomirski
2018-04-03 17:16             ` David Howells
2018-04-03 17:16               ` David Howells
2018-04-03 19:01               ` Andy Lutomirski
2018-04-03 19:01                 ` Andy Lutomirski
2018-04-03 19:49                 ` David Howells
2018-04-03 19:49                   ` David Howells
2018-04-03 21:58                   ` Andy Lutomirski
2018-04-03 21:58                     ` Andy Lutomirski
2018-04-03 22:32                     ` David Howells
2018-04-03 22:32                       ` David Howells
2018-04-03 22:39                       ` Andy Lutomirski
2018-04-03 22:39                         ` Andy Lutomirski
2018-04-03 22:46                         ` Linus Torvalds
2018-04-03 22:46                           ` Linus Torvalds
2018-04-03 22:51                           ` Matthew Garrett
2018-04-03 22:51                             ` Matthew Garrett
2018-04-03 22:53                             ` Andy Lutomirski
2018-04-03 22:53                               ` Andy Lutomirski
2018-04-03 23:08                               ` Justin Forbes
2018-04-03 23:09                               ` Matthew Garrett
2018-04-03 23:09                                 ` Matthew Garrett
2018-04-03 23:08                             ` Linus Torvalds
2018-04-03 23:08                               ` Linus Torvalds
2018-04-03 23:10                               ` Linus Torvalds
2018-04-03 23:10                                 ` Linus Torvalds
2018-04-03 23:17                               ` Matthew Garrett
2018-04-03 23:17                                 ` Matthew Garrett
2018-04-03 23:26                                 ` Linus Torvalds
2018-04-03 23:26                                   ` Linus Torvalds
2018-04-03 23:39                                   ` Linus Torvalds
2018-04-03 23:39                                     ` Linus Torvalds
2018-04-03 23:47                                     ` Matthew Garrett
2018-04-03 23:47                                       ` Matthew Garrett
2018-04-04  0:02                                       ` Linus Torvalds
2018-04-04  0:02                                         ` Linus Torvalds
2018-04-04  0:04                                         ` Matthew Garrett
2018-04-04  0:04                                           ` Matthew Garrett
2018-04-04  0:08                                           ` Linus Torvalds
2018-04-04  0:08                                             ` Linus Torvalds
2018-04-04  0:12                                             ` Matthew Garrett
2018-04-04  0:12                                               ` Matthew Garrett
2018-04-05 14:58                                               ` Alan Cox
2018-04-05 14:58                                                 ` Alan Cox
2018-04-04  0:22                                             ` David Howells
2018-04-04  0:22                                               ` David Howells
2018-04-04  0:22                                               ` David Howells
2018-04-05 17:59                                           ` Alan Cox
2018-04-05 17:59                                             ` Alan Cox
2018-04-05 18:03                                             ` Matthew Garrett
2018-04-05 18:03                                               ` Matthew Garrett
2018-04-03 23:45                                   ` Matthew Garrett
2018-04-03 23:45                                     ` Matthew Garrett
2018-04-03 23:55                                     ` Linus Torvalds
2018-04-03 23:55                                       ` Linus Torvalds
2018-04-03 23:59                                       ` Matthew Garrett
2018-04-03 23:59                                         ` Matthew Garrett
2018-04-04  0:06                                         ` Linus Torvalds
2018-04-04  0:06                                           ` Linus Torvalds
2018-04-04  0:10                                           ` Matthew Garrett
2018-04-04  0:10                                             ` Matthew Garrett
2018-04-04  0:15                                             ` Linus Torvalds
2018-04-04  0:15                                               ` Linus Torvalds
2018-04-04  0:16                                               ` Matthew Garrett
2018-04-04  0:16                                                 ` Matthew Garrett
2018-04-04  0:18                                                 ` Andy Lutomirski
2018-04-04  0:18                                                   ` Andy Lutomirski
2018-04-04  0:19                                                   ` Matthew Garrett
2018-04-04  0:19                                                     ` Matthew Garrett
2018-04-04  9:04                                                     ` Greg Kroah-Hartman
2018-04-04  9:04                                                       ` Greg Kroah-Hartman
2018-04-04  0:25                                                 ` Linus Torvalds
2018-04-04  0:25                                                   ` Linus Torvalds
2018-04-04  0:33                                                   ` Linus Torvalds
2018-04-04  0:33                                                     ` Linus Torvalds
2018-04-04  0:46                                                     ` Matthew Garrett
2018-04-04  0:46                                                       ` Matthew Garrett
2018-04-04  0:56                                                       ` Linus Torvalds
2018-04-04  0:56                                                         ` Linus Torvalds
2018-04-04  1:13                                                         ` Matthew Garrett
2018-04-04  1:13                                                           ` Matthew Garrett
2018-04-04  1:43                                                           ` Linus Torvalds
2018-04-04  1:43                                                             ` Linus Torvalds
2018-04-04  4:30                                                             ` Matthew Garrett
2018-04-04  4:30                                                               ` Matthew Garrett
2018-04-04 12:57                                                               ` Theodore Y. Ts'o
2018-04-04 12:57                                                                 ` Theodore Y. Ts'o
2018-04-04 13:02                                                                 ` Greg Kroah-Hartman
2018-04-04 13:02                                                                   ` Greg Kroah-Hartman
2018-04-04 13:34                                                                   ` Theodore Y. Ts'o
2018-04-04 13:34                                                                     ` Theodore Y. Ts'o
2018-04-04 13:57                                                                     ` Greg Kroah-Hartman
2018-04-04 13:57                                                                       ` Greg Kroah-Hartman
2018-04-04 13:29                                                                 ` Mike Galbraith
2018-04-04 13:29                                                                   ` Mike Galbraith
2018-04-04 13:33                                                                 ` David Howells
2018-04-04 13:33                                                                   ` David Howells
2018-04-04 13:52                                                                   ` Theodore Y. Ts'o [this message]
2018-04-04 13:52                                                                     ` Theodore Y. Ts'o
2018-04-04 13:57                                                                     ` David Howells
2018-04-04 13:57                                                                       ` David Howells
2018-04-04 16:22                                                                     ` Matthew Garrett
2018-04-04 16:22                                                                       ` Matthew Garrett
2018-04-04 16:39                                                                       ` Andy Lutomirski
2018-04-04 16:39                                                                         ` Andy Lutomirski
2018-04-04 16:42                                                                         ` Matthew Garrett
2018-04-04 16:42                                                                           ` Matthew Garrett
2018-04-04 16:46                                                                         ` Justin Forbes
2018-04-04 16:46                                                                           ` Justin Forbes
2018-04-05  0:05                                                                       ` Peter Dolding
2018-04-05  0:05                                                                         ` Peter Dolding
2018-04-05  0:20                                                                         ` Matthew Garrett
2018-04-05  0:20                                                                           ` Matthew Garrett
2018-04-04 16:20                                                                 ` Matthew Garrett
2018-04-04 16:20                                                                   ` Matthew Garrett
2018-04-08 22:00                                                                 ` Pavel Machek
2018-04-04 16:09                                                               ` Linus Torvalds
2018-04-04 16:09                                                                 ` Linus Torvalds
2018-04-04 16:17                                                                 ` Matthew Garrett
2018-04-04 16:17                                                                   ` Matthew Garrett
2018-04-04  6:56                                                           ` Peter Dolding
2018-04-04  6:56                                                             ` Peter Dolding
2018-04-04 16:26                                                             ` Matthew Garrett
2018-04-04 16:26                                                               ` Matthew Garrett
2018-04-05  1:28                                                               ` Peter Dolding
2018-04-05  1:28                                                                 ` Peter Dolding
2018-04-04  1:30                                                         ` Justin Forbes
2018-04-04  1:58                                                           ` Linus Torvalds
2018-04-04  1:58                                                             ` Linus Torvalds
2018-04-04  1:36                                                         ` Justin Forbes
2018-04-04  1:36                                                           ` Justin Forbes
2018-04-04  0:17                                           ` Jann Horn
2018-04-04  0:17                                             ` Jann Horn
2018-04-04  0:23                                             ` Andy Lutomirski
2018-04-04  0:23                                               ` Andy Lutomirski
2018-04-04  8:05                                               ` David Howells
2018-04-04  8:05                                                 ` David Howells
2018-04-04  8:05                                                 ` David Howells
2018-04-04 14:35                                                 ` Andy Lutomirski
2018-04-04 14:35                                                   ` Andy Lutomirski
2018-04-04 14:44                                                   ` David Howells
2018-04-04 14:44                                                     ` David Howells
2018-04-04 14:44                                                     ` David Howells
2018-04-04 15:43                                                 ` Eric W. Biederman
2018-04-04 15:43                                                   ` Eric W. Biederman
2018-04-03 23:56                                   ` David Howells
2018-04-03 23:56                                     ` David Howells
2018-04-03 23:56                                     ` David Howells
2018-04-03 23:58                                     ` Linus Torvalds
2018-04-03 23:58                                       ` Linus Torvalds
2018-04-03 23:39                           ` David Howells
2018-04-03 23:39                             ` David Howells
2018-04-03 23:48                             ` Andy Lutomirski
2018-04-03 23:48                               ` Andy Lutomirski
2018-04-08  8:23                             ` Pavel Machek
2018-04-03 23:12                         ` David Howells
2018-04-03 23:12                           ` David Howells
2018-04-03 23:27                           ` Linus Torvalds
2018-04-03 23:27                             ` Linus Torvalds
2018-04-03 23:42                           ` Andy Lutomirski
2018-04-03 23:42                             ` Andy Lutomirski
2018-04-03 18:45             ` Kees Cook
2018-04-03 18:45               ` Kees Cook
2018-04-03 19:01               ` Andy Lutomirski
2018-04-03 19:01                 ` Andy Lutomirski
2018-04-03 19:07                 ` Kees Cook
2018-04-03 19:07                   ` Kees Cook
2018-04-03 19:29             ` Matthew Garrett
2018-04-03 19:29               ` Matthew Garrett
2018-04-03 21:51               ` Andy Lutomirski
2018-04-03 21:51                 ` Andy Lutomirski
2018-04-04 18:42                 ` Peter Jones
2018-04-04 18:42                   ` Peter Jones
2018-04-04 20:01                   ` Thomas Gleixner
2018-04-04 20:01                     ` Thomas Gleixner
2018-04-04 20:18                     ` Matthew Garrett
2018-04-04 20:18                       ` Matthew Garrett
2018-04-05 18:47                   ` Andy Lutomirski
2018-04-05 18:47                     ` Andy Lutomirski
2018-04-06  4:42                   ` Peter Dolding
2018-04-06  4:42                     ` Peter Dolding
2018-04-03 20:53           ` Linus Torvalds
2018-04-03 20:53             ` Linus Torvalds
2018-04-03 20:54             ` Matthew Garrett
2018-04-03 20:54               ` Matthew Garrett
2018-04-03 21:01               ` Linus Torvalds
2018-04-03 21:01                 ` Linus Torvalds
2018-04-03 21:08                 ` Matthew Garrett
2018-04-03 21:08                   ` Matthew Garrett
2018-04-03 21:21                   ` Al Viro
2018-04-03 21:21                     ` Al Viro
2018-04-03 21:37                     ` Matthew Garrett
2018-04-03 21:37                       ` Matthew Garrett
2018-04-03 21:26                   ` Linus Torvalds
2018-04-03 21:26                     ` Linus Torvalds
2018-04-03 21:32                     ` Matthew Garrett
2018-04-03 21:32                       ` Matthew Garrett
2018-04-08  8:10                   ` Pavel Machek
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  2:34 ` Alexei Starovoitov
2018-04-04  4:31 ` Matthew Garrett
2018-04-04  4:31   ` Matthew Garrett
2018-04-08  7:44   ` joeyli
2018-04-08  7:44     ` joeyli
2018-04-08  8:07 ` joeyli
2018-04-08  8:07   ` joeyli
2018-04-09  3:40   ` Alexei Starovoitov
2018-04-09  3:40     ` Alexei Starovoitov
2018-04-09  8:14     ` Daniel Borkmann
2018-04-09  8:14       ` Daniel Borkmann
2018-04-09 13:55     ` joeyli
2018-04-09 13:55       ` joeyli
2017-10-26 16:37 David Howells
2017-10-26 16:37 ` David Howells
2017-10-26 16:37 ` David Howells
     [not found] ` <29447.1509035858-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2017-10-26 18:22   ` Mimi Zohar
2017-10-26 18:22     ` Mimi Zohar
2017-10-26 18:22     ` Mimi Zohar
2017-10-26 19:20   ` James Morris
2017-10-26 19:20     ` James Morris
2017-10-26 19:20     ` James Morris

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