[PATCH V31 14/25] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down

[Matthew Garrett]

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>
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx>
cc: Dave Young <dyoung@xxxxxxxxxx>
cc: linux-acpi@xxxxxxxxxxxxxxx
---
 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 f29e427d0d1d..cd5bba7b8eb3 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -194,7 +194,8 @@ acpi_physical_address __init acpi_os_get_root_pointer(void)
 	acpi_physical_address pa;
 
 #ifdef CONFIG_KEXEC
-	if (acpi_rsdp)
+	if (acpi_rsdp && !kernel_is_locked_down("ACPI RSDP specification",
+						LOCKDOWN_INTEGRITY))
 		return acpi_rsdp;
 #endif
 	pa = acpi_arch_get_root_pointer();
-- 
2.21.0.392.gf8f6787159e-goog