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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Matthew Garrett <matthewgarrett@google.com>
Cc: James Morris <jmorris@namei.org>,
	linux-security-module <linux-security-module@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-api@vger.kernel.org, Matthew Garrett <mjg59@google.com>,
	linux-efi <linux-efi@vger.kernel.org>
Subject: Re: [PATCH V34 28/29] efi: Restrict efivar_ssdt_load when the kernel is locked down
Date: Tue, 25 Jun 2019 17:00:24 +0200	[thread overview]
Message-ID: <CAKv+Gu_0bSCdeUGQo=nnKU=mfHXu+-U+qXWqJpJGUd6dVZF61Q@mail.gmail.com> (raw)
In-Reply-To: <20190622000358.19895-29-matthewgarrett@google.com>

On Sat, 22 Jun 2019 at 02:05, Matthew Garrett <matthewgarrett@google.com> wrote:
>
> efivar_ssdt_load allows the kernel to import arbitrary ACPI code from an
> EFI variable, which gives arbitrary code execution in ring 0. Prevent
> that when the kernel is locked down.
>
> Signed-off-by: Matthew Garrett <mjg59@google.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: linux-efi@vger.kernel.org

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---
>  drivers/firmware/efi/efi.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 55b77c576c42..9f92a013ab27 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -31,6 +31,7 @@
>  #include <linux/acpi.h>
>  #include <linux/ucs2_string.h>
>  #include <linux/memblock.h>
> +#include <linux/security.h>
>
>  #include <asm/early_ioremap.h>
>
> @@ -242,6 +243,11 @@ static void generic_ops_unregister(void)
>  static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata;
>  static int __init efivar_ssdt_setup(char *str)
>  {
> +       int ret = security_locked_down(LOCKDOWN_ACPI_TABLES);
> +
> +       if (ret)
> +               return ret;
> +
>         if (strlen(str) < sizeof(efivar_ssdt))
>                 memcpy(efivar_ssdt, str, strlen(str));
>         else
> --
> 2.22.0.410.gd8fdbe21b5-goog
>

  parent reply	other threads:[~2019-06-25 15:00 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-22  0:03 [PATCH V34 00/29] Lockdown as an LSM Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 01/29] security: Support early LSMs Matthew Garrett
2019-06-22 23:36   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-06-22 23:37   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-06-22 23:37   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 04/29] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-06-22 23:48   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 05/29] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-06-22 23:52   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-06-22 23:52   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-06-22 23:53   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-06-24  2:01   ` Dave Young
2019-06-25  2:35     ` Dave Young
2019-06-22  0:03 ` [PATCH V34 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-06-22 23:54   ` Kees Cook
2019-06-27  4:59   ` James Morris
2019-06-27 15:28     ` Matthew Garrett
2019-06-27 18:14       ` James Morris
2019-06-27 23:17         ` Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 10/29] hibernate: Disable when " Matthew Garrett
2019-06-22 17:52   ` Pavel Machek
2019-06-24 13:21     ` Jiri Kosina
2019-07-10 15:26       ` Joey Lee
2019-07-11  4:11       ` joeyli
2019-06-22 23:55   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-06-22 23:55   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 12/29] x86: Lock down IO port " Matthew Garrett
2019-06-22 23:58   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-06-22 23:59   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-06-22 23:59   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-06-23  0:00   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 17/29] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-06-23  0:00   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 18/29] Lock down TIOCSSERIAL Matthew Garrett
2019-06-23  0:01   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 19/29] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-06-23  0:04   ` Kees Cook
2019-06-27  1:49   ` Daniel Axtens
2019-06-27 15:30     ` Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-06-23  0:04   ` Kees Cook
2019-06-23 11:08   ` Thomas Gleixner
2019-06-22  0:03 ` [PATCH V34 21/29] Lock down /proc/kcore Matthew Garrett
2019-06-23  0:05   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 22/29] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-06-23  0:09   ` Kees Cook
2019-06-23  1:57   ` Masami Hiramatsu
2019-06-22  0:03 ` [PATCH V34 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-06-23  0:09   ` Kees Cook
2019-06-24 15:15   ` Daniel Borkmann
2019-06-24 19:54     ` Matthew Garrett
2019-06-24 20:08       ` Andy Lutomirski
2019-06-24 20:15         ` Matthew Garrett
2019-06-24 20:59         ` Daniel Borkmann
2019-06-24 21:30           ` Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 24/29] Lock down perf when " Matthew Garrett
2019-06-23  0:12   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 27/29] tracefs: Restrict tracefs " Matthew Garrett
2019-06-22  0:03 ` [PATCH V34 28/29] efi: Restrict efivar_ssdt_load " Matthew Garrett
2019-06-23  0:14   ` Kees Cook
2019-06-25 15:00   ` Ard Biesheuvel [this message]
2019-06-22  0:03 ` [PATCH V34 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-06-23  0:25   ` Kees Cook
2019-06-24 23:01 ` [PATCH V34 00/29] Lockdown as an LSM James Morris
2019-06-24 23:47   ` Casey Schaufler
2019-06-24 23:56   ` Matthew Garrett
2019-06-25  6:04     ` James Morris
2019-06-25  8:16   ` John Johansen

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