From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
Matthew Garrett <matthewgarrett@google.com>,
Matthew Garrett <mjg59@google.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Kees Cook <keescook@chromium.org>,
linux-efi@vger.kernel.org
Subject: [PATCH V35 28/29] efi: Restrict efivar_ssdt_load when the kernel is locked down
Date: Mon, 15 Jul 2019 12:59:45 -0700 [thread overview]
Message-ID: <20190715195946.223443-29-matthewgarrett@google.com> (raw)
In-Reply-To: <20190715195946.223443-1-matthewgarrett@google.com>
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>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.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 ad3b1f4866b3..776f479e5499 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -30,6 +30,7 @@
#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
--
2.22.0.510.g264f2c817a-goog
next prev parent reply other threads:[~2019-07-15 20:01 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 19:59 [PATCH V35 00/29] Kernel lockdown functionality Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 01/29] security: Support early LSMs Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 04/29] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 05/29] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 10/29] hibernate: Disable when " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 12/29] x86: Lock down IO port " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-07-16 2:59 ` Dave Young
2019-07-16 20:34 ` Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 17/29] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 18/29] Lock down TIOCSSERIAL Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 19/29] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-07-15 23:26 ` James Morris
2019-07-15 19:59 ` [PATCH V35 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 21/29] Lock down /proc/kcore Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 22/29] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-07-15 22:54 ` Daniel Borkmann
2019-07-16 20:32 ` Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 24/29] Lock down perf when " Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-07-15 19:59 ` [PATCH V35 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-07-15 23:17 ` James Morris
2019-07-15 19:59 ` [PATCH V35 27/29] tracefs: Restrict tracefs " Matthew Garrett
2019-07-16 23:14 ` Steven Rostedt
2019-07-16 23:22 ` Matthew Garrett
2019-07-15 19:59 ` Matthew Garrett [this message]
2019-07-15 19:59 ` [PATCH V35 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett
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