[PATCH V32 14/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down

From: Matthew Garrett
Date: Wed Apr 03 2019 - 20:34:58 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>
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