lkml.org 
[lkml]   [2017]   [Oct]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 14/27] ACPI: Limit access to custom_method when the kernel is locked down
On Thu, Oct 19, 2017 at 03:52:19PM +0100, David Howells wrote:
> From: Matthew Garrett <matthew.garrett@nebula.com>
>
> custom_method effectively allows arbitrary access to system memory, making
> it possible for an attacker to circumvent restrictions on module loading.
> Disable it if the kernel is locked down.
>
> Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
> Signed-off-by: David Howells <dhowells@redhat.com>

I have reviewed this patch. Please feel free to add:

Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>

Thanks!
Joey Lee

> cc: linux-acpi@vger.kernel.org
> ---
>
> drivers/acpi/custom_method.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
> index c68e72414a67..b33fba70ec51 100644
> --- a/drivers/acpi/custom_method.c
> +++ b/drivers/acpi/custom_method.c
> @@ -29,6 +29,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf,
> struct acpi_table_header table;
> acpi_status status;
>
> + if (kernel_is_locked_down("ACPI custom methods"))
> + return -EPERM;
> +
> if (!(*ppos)) {
> /* parse the table header to get the table length */
> if (count <= sizeof(struct acpi_table_header))
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-efi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html

\
 
 \ /
  Last update: 2017-10-22 17:34    [W:0.854 / U:1.552 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site