sctp: translate host order to network order when setting a hmacid

now sctp auth cannot work well when setting a hmacid manually, which
is caused by that we didn't use the network order for hmacid, so fix
it by adding the transformation in sctp_auth_ep_set_hmacs.

even we set hmacid with the network order in userspace, it still
can't work, because of this condition in sctp_auth_ep_set_hmacs():

		if (id > SCTP_AUTH_HMAC_ID_MAX)
			return -EOPNOTSUPP;

so this wasn't working before and thus it won't break compatibility.

Fixes: 65b07e5d0d09 ("[SCTP]: API updates to suport SCTP-AUTH extensions.")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/auth.c

@@ -809,8 +809,8 @@ int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
 	if (!has_sha1)
 		return -EINVAL;
 
-	memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0],
-		hmacs->shmac_num_idents * sizeof(__u16));
+	for (i = 0; i < hmacs->shmac_num_idents; i++)
+		ep->auth_hmacs_list->hmac_ids[i] = htons(hmacs->shmac_idents[i]);
 	ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) +
 				hmacs->shmac_num_idents * sizeof(__u16));
 	return 0;