ACPICA: Interpreter: fix memory leak by using existing buffer

ACPICA commit 52d1da5dcbd79a722b70f02a1a83f04088f51ff6

There was a memory leak that ocurred when a _CID object is defined as
a package containing string objects. When _CID is checked for any
possible repairs, it calls a helper function to repair _HID (because
_CID basically contains multiple _HID entries).

The _HID repair function assumes that string objects are standalone
objects that are not contained inside of any packages. The _HID
repair function replaces the string object with a brand new object
and attempts to delete the old object by decrementing the reference
count of the old object. Strings inside of packages have a reference
count of 2 so the _HID repair function leaves this object in a
dangling state and causes a memory leak.

Instead of allocating a brand new object and removing the old object,
use the existing object when repairing the _HID object.

Link: https://github.com/acpica/acpica/commit/52d1da5d
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/nsrepair2.c

@@ -495,9 +495,8 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 		   union acpi_operand_object **return_object_ptr)
 {
 	union acpi_operand_object *return_object = *return_object_ptr;
-	union acpi_operand_object *new_string;
-	char *source;
 	char *dest;
+	char *source;
 
 	ACPI_FUNCTION_NAME(ns_repair_HID);
 
@@ -518,13 +517,6 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 		return_ACPI_STATUS(AE_OK);
 	}
 
-	/* It is simplest to always create a new string object */
-
-	new_string = acpi_ut_create_string_object(return_object->string.length);
-	if (!new_string) {
-		return_ACPI_STATUS(AE_NO_MEMORY);
-	}
-
 	/*
 	 * Remove a leading asterisk if present. For some unknown reason, there
 	 * are many machines in the field that contains IDs like this.
@@ -534,7 +526,7 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 	source = return_object->string.pointer;
 	if (*source == '*') {
 		source++;
-		new_string->string.length--;
+		return_object->string.length--;
 
 		ACPI_DEBUG_PRINT((ACPI_DB_REPAIR,
 				  "%s: Removed invalid leading asterisk\n",
@@ -549,12 +541,11 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 	 * "NNNN####" where N is an uppercase letter or decimal digit, and
 	 * # is a hex digit.
 	 */
-	for (dest = new_string->string.pointer; *source; dest++, source++) {
+	for (dest = return_object->string.pointer; *source; dest++, source++) {
 		*dest = (char)toupper((int)*source);
 	}
+	return_object->string.pointer[return_object->string.length] = 0;
 
-	acpi_ut_remove_reference(return_object);
-	*return_object_ptr = new_string;
 	return_ACPI_STATUS(AE_OK);
 }