[PATCH 15/16] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down

From: David Howells
Date: Wed Nov 16 2016 - 16:49:17 EST

From: Josh Boyer <jwboyer@xxxxxxxxxx>

This option allows userspace to pass the RSDP address to the kernel, which
makes it possible for a user to circumvent any restrictions imposed on
loading modules. Ignore the option when the kernel is locked down.

Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>

drivers/acpi/osl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 416953a42510..fb1dc79a7f1b 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -40,6 +40,7 @@
#include <linux/list.h>
#include <linux/jiffies.h>
#include <linux/semaphore.h>
+#include <linux/security.h>

#include <asm/io.h>
#include <asm/uaccess.h>
@@ -191,7 +192,7 @@ early_param("acpi_rsdp", setup_acpi_rsdp);
acpi_physical_address __init acpi_os_get_root_pointer(void)
- if (acpi_rsdp)
+ if (acpi_rsdp && !kernel_is_locked_down())
return acpi_rsdp;