On Tue, 3 Sep 2013, Matthew Garrett wrote:
> custom_method effectively allows arbitrary access to system memory, making
> it possible for an attacker to circumvent restrictions on module loading.
> Disable it if any such restrictions have been enabled.
>
> Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
Reviewed-by: James Morris <jmorris@xxxxxxxxx>
> ---
> 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 12b62f2..50647b3 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 (secure_modules())
> + return -EPERM;
> +
> if (!(*ppos)) {
> /* parse the table header to get the table length */
> if (count <= sizeof(struct acpi_table_header))
> --
> 1.8.3.1
>
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--
James Morris
<jmorris@xxxxxxxxx>
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