Commit 046ece77 authored Oct 02, 2023 by Andy Shevchenko Committed by Rafael J. Wysocki Oct 03, 2023

ACPI: property: Allow _DSD buffer data only for byte accessors

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: 369af6bf ("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>
[ rjw: Add missing braces ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 8a749fd1

drivers/acpi/property.c

+10 −9

Original line number	Diff line number	Diff line
		@@ -1102,25 +1102,26 @@ 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;
		}
		fallthrough;
		default:
		} else {
		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;
		}

		switch (proptype) {
		case DEV_PROP_U8: