sctp: check asoc peer.asconf_capable before processing asconf

asconf chunks should be dropped when the asoc doesn't support
asconf feature.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sctp/sm_statefuns.c

@@ -3721,7 +3721,8 @@ enum sctp_disposition sctp_sf_do_asconf(struct net *net,
 	 * is received unauthenticated it MUST be silently discarded as
 	 * described in [I-D.ietf-tsvwg-sctp-auth].
 	 */
-	if (!net->sctp.addip_noauth && !chunk->auth)
+	if (!asoc->peer.asconf_capable ||
+	    (!net->sctp.addip_noauth && !chunk->auth))
 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
 					     commands);
 
@@ -3863,7 +3864,8 @@ enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
 	 * is received unauthenticated it MUST be silently discarded as
 	 * described in [I-D.ietf-tsvwg-sctp-auth].
 	 */
-	if (!net->sctp.addip_noauth && !asconf_ack->auth)
+	if (!asoc->peer.asconf_capable ||
+	    (!net->sctp.addip_noauth && !asconf_ack->auth))
 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
 					     commands);