From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>,
David Howells <dhowells@redhat.com>
Cc: torvalds@linux-foundation.org, linux-man@vger.kernel.org,
linux-api@vger.kernel.org, jmorris@namei.org,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH 06/24] kexec_load: Disable at runtime if the kernel is locked down
Date: Wed, 11 Apr 2018 16:09:35 -0400 [thread overview]
Message-ID: <1523477375.5268.78.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <87po35k1q6.fsf@xmission.com>
On Wed, 2018-04-11 at 14:00 -0500, Eric W. Biederman wrote:
> David Howells <dhowells@redhat.com> writes:
>
> > From: Matthew Garrett <mjg59@srcf.ucam.org>
> >
> > The kexec_load() syscall permits the loading and execution of arbitrary
> > code in ring 0, which is something that lock-down is meant to prevent. It
> > makes sense to disable kexec_load() in this situation.
> >
> > This does not affect kexec_file_load() syscall which can check for a
> > signature on the image to be booted.
>
> Maybing I am missing it but I am not seeing anything that would require
> kexec_file_load be configured such that it checks the loaded kernel.
>
> Without that I don't see the point of disabling kexec_load.
>
> Nacked-by: "Eric W. Biederman" <ebiederm@xmission.com>
The IMA "secure boot" policy requires the kexec image to be signed.
This call to kernel_is_locked_down() could be replaced with a call
to security_kernel_read_file(NULL, READING_KEXEC_IMAGE).
It would be similar to the existing init_module syscall calling
security_kernel_read_file().
Mimi
next prev parent reply other threads:[~2018-04-11 20:09 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-11 16:24 [PATCH 00/24] security: Add kernel lockdown David Howells
2018-04-11 16:24 ` [PATCH 01/24] Add the ability to lock down access to the running kernel image David Howells
2018-04-11 16:44 ` Jann Horn
2018-04-11 17:37 ` Randy Dunlap
2018-04-11 18:50 ` Miguel Ojeda
2018-04-11 19:56 ` Greg KH
2018-04-11 17:49 ` David Howells
2018-04-11 18:09 ` Linus Torvalds
2018-04-11 18:35 ` Justin Forbes
2018-04-11 21:05 ` Jordan Glover
2018-04-11 22:38 ` Linus Torvalds
2018-04-12 13:09 ` Justin Forbes
2018-04-12 16:52 ` Linus Torvalds
2018-04-12 2:57 ` Andy Lutomirski
2018-04-11 16:24 ` [PATCH 02/24] Add a SysRq option to lift kernel lockdown David Howells
2018-04-11 17:05 ` Jann Horn
2018-04-13 20:22 ` Pavel Machek
2018-04-11 16:24 ` [PATCH 03/24] ima: require secure_boot rules in lockdown mode David Howells
2018-04-11 16:25 ` [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells
2018-04-11 16:25 ` [PATCH 05/24] Restrict /dev/{mem, kmem, port} when " David Howells
2018-04-11 16:25 ` [PATCH 06/24] kexec_load: Disable at runtime if " David Howells
2018-04-11 19:00 ` Eric W. Biederman
2018-04-11 20:09 ` Mimi Zohar [this message]
2018-04-12 11:38 ` Mimi Zohar
2018-04-11 20:05 ` David Howells
2018-04-11 16:25 ` [PATCH 07/24] hibernate: Disable when " David Howells
2018-04-13 20:22 ` Pavel Machek
2018-04-19 14:38 ` David Howells
2018-04-22 14:34 ` Andy Lutomirski
2018-04-26 7:26 ` Pavel Machek
2018-04-26 7:34 ` Rafael J. Wysocki
2018-04-26 8:20 ` Jiri Kosina
2018-05-23 8:46 ` joeyli
2018-04-11 16:25 ` [PATCH 08/24] uswsusp: " David Howells
2018-04-11 16:25 ` [PATCH 09/24] PCI: Lock down BAR access " David Howells
2018-04-11 16:25 ` [PATCH 10/24] x86: Lock down IO port " David Howells
2018-04-11 16:25 ` [PATCH 11/24] x86/msr: Restrict MSR " David Howells
2018-04-11 16:25 ` [PATCH 12/24] ACPI: Limit access to custom_method " David Howells
2018-04-11 16:26 ` [PATCH 13/24] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2018-04-11 16:26 ` [PATCH 14/24] acpi: Disable ACPI table override if the kernel is " David Howells
2018-04-11 16:26 ` [PATCH 15/24] acpi: Disable APEI error injection " David Howells
2018-04-11 16:26 ` [PATCH 16/24] Prohibit PCMCIA CIS storage when " David Howells
2018-04-11 16:26 ` [PATCH 17/24] Lock down TIOCSSERIAL David Howells
2018-04-11 16:26 ` [PATCH 18/24] Lock down module params that specify hardware parameters (eg. ioport) David Howells
2018-04-11 17:22 ` Randy Dunlap
2018-04-11 16:26 ` [PATCH 19/24] x86/mmiotrace: Lock down the testmmiotrace module David Howells
2018-04-11 16:26 ` [PATCH 20/24] Lock down /proc/kcore David Howells
2018-04-11 16:26 ` [PATCH 21/24] Lock down kprobes David Howells
2018-04-11 16:27 ` [PATCH 22/24] bpf: Restrict kernel image access functions when the kernel is locked down David Howells
2018-04-11 16:27 ` [PATCH 23/24] Lock down perf David Howells
2018-04-11 16:27 ` [PATCH 24/24] debugfs: Restrict debugfs when the kernel is locked down David Howells
2018-04-11 17:26 ` Randy Dunlap
2018-04-11 18:50 ` Eric W. Biederman
2018-04-11 19:54 ` Greg KH
2018-04-11 20:08 ` David Howells
2018-04-11 20:09 ` David Howells
2018-04-11 20:33 ` Greg KH
2018-04-12 2:54 ` Andy Lutomirski
2018-04-12 8:23 ` Greg KH
2018-04-12 14:19 ` Andy Lutomirski
2018-04-13 20:22 ` Pavel Machek
2018-04-19 14:35 ` David Howells
2018-05-10 11:01 ` Pavel Machek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1523477375.5268.78.camel@linux.vnet.ibm.com \
--to=zohar@linux.vnet.ibm.com \
--cc=dhowells@redhat.com \
--cc=ebiederm@xmission.com \
--cc=jmorris@namei.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-man@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).