From: Xin Long <lucien.xin@gmail.com>
Date: Sat, 30 Jul 2016 13:58:35 +0800

sctp needs to queue auth chunk back when we know that we are going
to generate another segment. But commit f1533cce60d1 ("sctp: fix
panic when sending auth chunks") requeues the last chunk processed
which is probably not the auth chunk.

It causes panic when calculating the MAC in sctp_auth_calculate_hmac(),
as the incorrect offset of the auth chunk in skb->data.

This fix is to requeue it by using packet->auth.

Fixes: f1533cce60d1 ("sctp: fix panic when sending auth chunks")
Signed-off-by: Xin Long <lucien.xin@gmail.com>

Applied.