HID: fix parsing of local delimiter with size 0

Acording to HID standard 1.11, value 0 allows for size being 0.
Local delimiter tag has has 0 one of the possible values.

Therefore we need to handle this case properly, to be fully compliant
with the specification.

Reported-by: Marcin Tolysz <tolysz@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 6462c92..a4b496c 100644 (file)
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -387,7 +387,8 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
        __u32 data;
        unsigned n;
 
-       if (item->size == 0) {
+       /* Local delimiter could have value 0, which allows size to be 0 */
+       if (item->size == 0 && item->tag != HID_LOCAL_ITEM_TAG_DELIMITER) {
                dbg_hid("item data expected for local item\n");
                return -1;
        }