From: "H. Peter Anvin" <hpa@zytor.com>
To: Matthew Garrett <matthew.garrett@nebula.com>
Cc: linux-kernel@vger.kernel.org, keescook@chromium.org,
gregkh@linuxfoundation.org, linux-efi@vger.kernel.org,
jmorris@namei.org, linux-security-module@vger.kernel.org
Subject: Re: [PATCH 01/12] Add BSD-style securelevel support
Date: Mon, 09 Sep 2013 09:27:08 -0700 [thread overview]
Message-ID: <522DF6DC.1050303@zytor.com> (raw)
In-Reply-To: <1378741786-18430-2-git-send-email-matthew.garrett@nebula.com>
On 09/09/2013 08:49 AM, Matthew Garrett wrote:
> Provide a coarse-grained runtime configuration option for restricting
> userspace's ability to modify the running kernel.
>
> Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
> ---
> Documentation/security/securelevel.txt | 23 +++++++
> include/linux/security.h | 8 +++
> security/Kconfig | 8 +++
> security/Makefile | 1 +
> security/securelevel.c | 116 +++++++++++++++++++++++++++++++++
> 5 files changed, 156 insertions(+)
> create mode 100644 Documentation/security/securelevel.txt
> create mode 100644 security/securelevel.c
>
> diff --git a/Documentation/security/securelevel.txt b/Documentation/security/securelevel.txt
> new file mode 100644
> index 0000000..a1355a0
> --- /dev/null
> +++ b/Documentation/security/securelevel.txt
> @@ -0,0 +1,23 @@
> +Linux securelevel interface
> +---------------------------
> +
> +The Linux securelevel interface (inspired by the BSD securelevel interface)
> +is a runtime mechanism for configuring coarse-grained kernel-level security
> +restrictions. It provides a runtime configuration variable at
> +/sys/kernel/security/securelevel which can be written to by root. The
> +following values are supported:
> +
> +-1: Permanently insecure mode. This level is equivalent to level 0, but once
> + set cannot be changed.
> +
> +0: Insecure mode (default). This level imposes no additional kernel
> + restrictions.
> +
> +1: Secure mode. If set, userspace will be unable to perform direct access
> + to PCI devices, port IO access, access system memory directly via
> + /dev/mem and /dev/kmem, perform kexec_load(), use the userspace
> + software suspend mechanism, insert new ACPI code at runtime via the
> + custom_method interface or modify CPU MSRs (on x86). Certain drivers
> + may also limit additional interfaces.
> +
This will break or have to be redefined once you have signed kexec.
-hpa
next prev parent reply other threads:[~2013-09-09 16:27 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-09 15:49 [PATCH 00/12] One more attempt at useful kernel lockdown Matthew Garrett
2013-09-09 15:49 ` [PATCH 01/12] Add BSD-style securelevel support Matthew Garrett
2013-09-09 16:27 ` H. Peter Anvin [this message]
2013-09-09 16:30 ` Matthew Garrett
2013-09-09 16:42 ` H. Peter Anvin
2013-09-09 16:44 ` Matthew Garrett
2013-09-09 16:51 ` H. Peter Anvin
2013-09-09 16:55 ` Matthew Garrett
2013-09-09 18:31 ` Matthew Garrett
2013-09-09 15:49 ` [PATCH 02/12] Enforce module signatures when securelevel is greater than 0 Matthew Garrett
2013-09-09 15:49 ` [PATCH 03/12] PCI: Lock down BAR access when securelevel is enabled Matthew Garrett
2013-09-09 15:49 ` [PATCH 04/12] x86: Lock down IO port " Matthew Garrett
2013-09-09 15:49 ` [PATCH 05/12] Restrict /dev/mem and /dev/kmem when securelevel is set Matthew Garrett
2013-09-09 15:49 ` [PATCH 06/12] acpi: Limit access to custom_method if " Matthew Garrett
2013-09-09 15:49 ` [PATCH 07/12] acpi: Ignore acpi_rsdp kernel parameter when " Matthew Garrett
2013-11-26 12:54 ` Josh Boyer
2013-09-09 15:49 ` [PATCH 08/12] kexec: Disable at runtime if securelevel has been set Matthew Garrett
2013-09-09 15:49 ` [PATCH 09/12] uswsusp: Disable when securelevel is set Matthew Garrett
2013-09-09 15:49 ` [PATCH 10/12] x86: Restrict MSR access " Matthew Garrett
2013-09-09 15:49 ` [PATCH 11/12] asus-wmi: Restrict debugfs interface " Matthew Garrett
2013-09-09 15:49 ` [PATCH 12/12] Add option to automatically set securelevel when in Secure Boot mode Matthew Garrett
2013-09-09 17:18 ` [PATCH 00/12] One more attempt at useful kernel lockdown Valdis.Kletnieks
2013-09-09 17:24 ` Matthew Garrett
2013-09-09 18:25 ` David Lang
2013-09-09 18:28 ` Matthew Garrett
2013-09-09 18:40 ` David Lang
2013-09-09 18:42 ` Matthew Garrett
2013-09-09 18:53 ` David Lang
2013-09-09 19:06 ` Matthew Garrett
2013-09-09 19:59 ` David Lang
2013-09-09 20:06 ` Matthew Garrett
2013-09-09 20:15 ` David Lang
2013-09-09 20:17 ` Matthew Garrett
2013-09-09 19:01 ` Valdis.Kletnieks
2013-09-09 19:08 ` Matthew Garrett
2013-09-09 19:41 ` H. Peter Anvin
2013-09-09 19:52 ` Josh Boyer
2013-09-09 19:56 ` H. Peter Anvin
2013-09-09 19:58 ` Josh Boyer
2013-09-09 20:02 ` H. Peter Anvin
2013-09-09 20:10 ` David Lang
2013-09-09 20:13 ` Josh Boyer
2013-09-09 23:02 ` Matthew Garrett
2013-09-09 23:19 ` David Lang
2013-09-09 23:20 ` Kees Cook
2013-09-09 23:30 ` James Bottomley
2013-09-09 23:34 ` Kees Cook
2013-09-10 0:53 ` Matthew Garrett
2013-09-10 2:44 ` David Lang
2013-09-10 2:55 ` Matthew Garrett
2013-09-10 3:09 ` David Lang
2013-09-10 3:53 ` Matthew Garrett
2013-09-10 17:23 ` Henrique de Moraes Holschuh
2013-09-10 18:26 ` Matthew Garrett
2013-09-10 18:29 ` H. Peter Anvin
2013-09-10 18:51 ` gregkh
2013-09-10 18:55 ` Kees Cook
2013-09-10 19:17 ` David Lang
2013-09-10 19:44 ` H. Peter Anvin
2013-09-10 23:43 ` Mimi Zohar
2013-09-10 23:48 ` H. Peter Anvin
2013-09-10 23:55 ` Mimi Zohar
2013-09-10 23:58 ` H. Peter Anvin
2013-09-10 18:48 ` Kees Cook
2013-09-11 9:32 ` joeyli
2013-09-09 20:30 ` Mimi Zohar
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