Re: [PATCH 10/12] acpi: Ignore acpi_rsdp kernel parameter in a secureboot environment

From: Dave Young
Date: Tue Mar 19 2013 - 04:48:15 EST


On 03/19/2013 05:32 AM, Matthew Garrett wrote:
> From: Josh Boyer <jwboyer@xxxxxxxxxx>
>
> This option allows userspace to pass the RSDP address to the kernel. This
> could potentially be used to circumvent the secure boot trust model.
> We ignore the setting if we don't have the CAP_COMPROMISE_KERNEL capability.
>
> Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxx>
> ---
> 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 586e7e9..0ef63f1 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -245,7 +245,7 @@ early_param("acpi_rsdp", setup_acpi_rsdp);
> acpi_physical_address __init acpi_os_get_root_pointer(void)
> {
> #ifdef CONFIG_KEXEC
> - if (acpi_rsdp)
> + if (acpi_rsdp && capable(CAP_COMPROMISE_KERNEL))
> return acpi_rsdp;
> #endif
>
>

This does not work because capable is not usable at this early point.

Josh, could you update your fix here?

--
Thanks
Dave


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