[PATCH 16/30] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down

From: David Howells
Date: Thu Nov 09 2017 - 12:32:46 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 modify the workings of hardware . Reject
the option when the kernel is locked down.

Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Reviewed-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
cc: Dave Young <dyoung@xxxxxxxxxx>
cc: linux-acpi@xxxxxxxxxxxxxxx
---

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

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index db78d353bab1..36c6527c1b0a 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -192,7 +192,7 @@ acpi_physical_address __init acpi_os_get_root_pointer(void)
acpi_physical_address pa = 0;

#ifdef CONFIG_KEXEC
- if (acpi_rsdp)
+ if (acpi_rsdp && !kernel_is_locked_down("ACPI RSDP specification"))
return acpi_rsdp;
#endif