Re: [PATCH v1 1/2] ACPI: property: Allow _DSD buffer data only for byte accessors

Rafael J. Wysocki
2023-10-03T13:59:41Z

On Mon, Oct 2, 2023 at 3:46 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> In accordance with ACPI specificication and _DSD data buffer
> representation the data there is an array of bytes. Hence,
> accessing it with something longer will create a sparse data
> which is against of how device property APIs work in general
> and also not defined in the ACPI specification (see [1]).
> Fix the code to emit an error if non-byte accessor is used to
> retrieve _DSD buffer data.
>
> Fixes: 369af6bf2c28 ("ACPI: property: Read buffer properties as integers")
> Link: https://uefi.org/specs/ACPI/6.5/19_ASL_Reference.html#buffer-declare-buffer-object [1]
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Applied along with the [2/2] as 6.7 material.

> ---
> drivers/acpi/property.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index 413e4fcadcaf..06550d8c619d 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -1102,25 +1102,25 @@ static int acpi_data_prop_read(const struct acpi_device_data *data,
> switch (proptype) {
> case DEV_PROP_STRING:
> break;
> - case DEV_PROP_U8 ... DEV_PROP_U64:
> + default:
> if (obj->type == ACPI_TYPE_BUFFER) {
> if (nval > obj->buffer.length)
> return -EOVERFLOW;
> - break;
> + } else {
> + if (nval > obj->package.count)
> + return -EOVERFLOW;
> }
> - fallthrough;
> - default:
> - if (nval > obj->package.count)
> - return -EOVERFLOW;
> break;
> }
> if (nval == 0)
> return -EINVAL;
>
> - if (obj->type != ACPI_TYPE_BUFFER)
> - items = obj->package.elements;
> - else
> + if (obj->type == ACPI_TYPE_BUFFER) {
> + if (proptype != DEV_PROP_U8)
> + return -EPROTO;
> items = obj;
> + } else
> + items = obj->package.elements;

The braces that are missing here (as per the coding style) were added
while applying the patch.

>
> switch (proptype) {
> case DEV_PROP_U8:
> --

Thanks!