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authorLinn Crosetto <lcrosetto@gmail.com>2019-08-19 17:17:52 -0700
committerJames Morris <jmorris@namei.org>2019-08-19 21:54:16 -0700
commit6ea0e815fc5e18597724169caa6e4d46dd8e693d (patch)
treee128c849c6b2a565b79967ee3b1457015993cc2d /drivers/acpi/tables.c
parent41fa1ee9c6d687afb05760dd349f361855f1d7f5 (diff)
acpi: Disable ACPI table override if the kernel is locked down
>From the kernel documentation (initrd_table_override.txt): If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to override nearly any ACPI table provided by the BIOS with an instrumented, modified one. When lockdown is enabled, the kernel should disallow any unauthenticated changes to kernel space. ACPI tables contain code invoked by the kernel, so do not allow ACPI tables to be overridden if the kernel is locked down. Signed-off-by: Linn Crosetto <lcrosetto@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Matthew Garrett <mjg59@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> cc: linux-acpi@vger.kernel.org Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'drivers/acpi/tables.c')
-rw-r--r--drivers/acpi/tables.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index de974322a197..b7c29a11c0c1 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -20,6 +20,7 @@
#include <linux/memblock.h>
#include <linux/earlycpio.h>
#include <linux/initrd.h>
+#include <linux/security.h>
#include "internal.h"
#ifdef CONFIG_ACPI_CUSTOM_DSDT
@@ -577,6 +578,11 @@ void __init acpi_table_upgrade(void)
if (table_nr == 0)
return;
+ if (security_locked_down(LOCKDOWN_ACPI_TABLES)) {
+ pr_notice("kernel is locked down, ignoring table override\n");
+ return;
+ }
+
acpi_tables_addr =
memblock_find_in_range(0, ACPI_TABLE_UPGRADE_MAX_PHYS,
all_tables_size, PAGE_SIZE);