platform/x86: asus-wmi: Potential buffer overflow in asus_wmi_evaluate_method_buf()

This code tests for if the obj->buffer.length is larger than the buffer
but then it just does the memcpy() anyway.

Fixes: 0f0ac158 ("platform/x86: asus-wmi: Add support for custom fan curves")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220413073744.GB8812@kiliReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/asus-wmi.c

@@ -371,10 +371,14 @@ static int asus_wmi_evaluate_method_buf(u32 method_id,
 
 	switch (obj->type) {
 	case ACPI_TYPE_BUFFER:
-		if (obj->buffer.length > size)
+		if (obj->buffer.length > size) {
 			err = -ENOSPC;
-		if (obj->buffer.length == 0)
+			break;
+		}
+		if (obj->buffer.length == 0) {
 			err = -ENODATA;
+			break;
+		}
 
 		memcpy(ret_buffer, obj->buffer.pointer, obj->buffer.length);
 		break;