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Date:   Wed,  6 Mar 2019 15:59:01 -0800
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Subject: [PATCH 15/27] acpi: Ignore acpi_rsdp kernel param when the kernel has
 been locked down
From:   Matthew Garrett <matthewgarrett@google.com>
To:     jmorris@namei.org
Cc:     linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, dhowells@redhat.com
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Sender: linux-kernel-owner@vger.kernel.org
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From: Josh Boyer <jwboyer@redhat.com>

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@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
cc: Dave Young <dyoung@redhat.com>
cc: linux-acpi@vger.kernel.org
Signed-off-by: Matthew Garrett <matthewgarrett@google.com>
---
 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 f29e427d0d1d..3e44cef7a0cd 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -194,7 +194,7 @@ 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"))
 		return acpi_rsdp;
 #endif
 	pa = acpi_arch_get_root_pointer();
-- 
2.21.0.352.gf09ad66450-goog