From: Mike Galbraith <efault@gmx.de>
To: "Theodore Y. Ts'o" <tytso@mit.edu>, Matthew Garrett <mjg59@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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>
Subject: Re: [GIT PULL] Kernel lockdown for secure boot
Date: Wed, 04 Apr 2018 15:29:03 +0200 [thread overview]
Message-ID: <1522848543.30109.3.camel@gmx.de> (raw)
In-Reply-To: <20180404125743.GB16242@thunk.org>
On Wed, 2018-04-04 at 08:57 -0400, Theodore Y. Ts'o wrote:
> On Wed, Apr 04, 2018 at 04:30:18AM +0000, Matthew Garrett wrote:
> > What I'm afraid of is this turning into a "security" feature that ends up
> > being circumvented in most scenarios where it's currently deployed - eg,
> > module signatures are mostly worthless in the non-lockdown case because you
> > can just grab the sig_enforce symbol address and then kexec a preamble that
> > flips it back to N regardless of the kernel config.
>
> 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?
>
> If lockdown simply included a requirement for a signed kernel for
> kexec --- and if kernel signing aren't available, to simply not alow
> kexec, wouldn't that take care of this case?
>
> This wouldn't even be all that much of a burden for non-distro users
> with lockdown enabled, since in my experience outside of enterprise
> and data center use cases, kexec isn't used...
Lots of folks use kdump, ergo kexec.
-Mike
WARNING: multiple messages have this Message-ID (diff)
From: efault@gmx.de (Mike Galbraith)
To: linux-security-module@vger.kernel.org
Subject: [GIT PULL] Kernel lockdown for secure boot
Date: Wed, 04 Apr 2018 15:29:03 +0200 [thread overview]
Message-ID: <1522848543.30109.3.camel@gmx.de> (raw)
In-Reply-To: <20180404125743.GB16242@thunk.org>
On Wed, 2018-04-04 at 08:57 -0400, Theodore Y. Ts'o wrote:
> On Wed, Apr 04, 2018 at 04:30:18AM +0000, Matthew Garrett wrote:
> > What I'm afraid of is this turning into a "security" feature that ends up
> > being circumvented in most scenarios where it's currently deployed - eg,
> > module signatures are mostly worthless in the non-lockdown case because you
> > can just grab the sig_enforce symbol address and then kexec a preamble that
> > flips it back to N regardless of the kernel config.
>
> 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?
>
> If lockdown simply included a requirement for a signed kernel for
> kexec --- and if kernel signing aren't available, to simply not alow
> kexec, wouldn't that take care of this case?
>
> This wouldn't even be all that much of a burden for non-distro users
> with lockdown enabled, since in my experience outside of enterprise
> and data center use cases, kexec isn't used...
Lots of folks use kdump, ergo kexec.
-Mike
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next prev parent reply other threads:[~2018-04-04 13:29 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 [this message]
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
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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