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

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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: 369af6bf2c ("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>
This commit is contained in:
Andy Shevchenko 2023-10-02 16:46:29 +03:00 committed by Rafael J. Wysocki
parent 8a749fd1a8
commit 046ece773c
1 changed files with 10 additions and 9 deletions
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19
drivers/acpi/property.c
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@ -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;
} 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;
}
switch (proptype) {
case DEV_PROP_U8: