sctp: check duplicate node before inserting a new transport

lxin · davem330 · commit cd2b70875058 · 2017-02-19T18:19:37.000-05:00
sctp has changed to use rhlist for transport rhashtable since commit 7fda702 ("sctp: use new rhlist interface on sctp transport rhashtable"). But rhltable_insert_key doesn't check the duplicate node when inserting a node, unlike rhashtable_lookup_insert_key. It may cause duplicate assoc/transport in rhashtable. like: client (addr A, B) server (addr X, Y) connect to X INIT (1) ------------> connect to Y INIT (2) ------------> INIT_ACK (1) <------------ INIT_ACK (2) <------------ After sending INIT (2), one transport will be created and hashed into rhashtable. But when receiving INIT_ACK (1) and processing the address params, another transport will be created and hashed into rhashtable with the same addr Y and EP as the last transport. This will confuse the assoc/transport's lookup. This patch is to fix it by returning err if any duplicate node exists before inserting it. Fixes: 7fda702 ("sctp: use new rhlist interface on sctp transport rhashtable") Reported-by: Fabio M. Di Nitto <fdinitto@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/input.c b/net/sctp/input.c
@@ -872,6 +872,8 @@ void sctp_transport_hashtable_destroy(void)
 
 int sctp_hash_transport(struct sctp_transport *t)
 {
+	struct sctp_transport *transport;
+	struct rhlist_head *tmp, *list;
 	struct sctp_hash_cmp_arg arg;
 	int err;
 
@@ -882,8 +884,19 @@ int sctp_hash_transport(struct sctp_transport *t)
 	arg.paddr = &t->ipaddr;
 	arg.lport = htons(t->asoc->base.bind_addr.port);
 
+	list = rhltable_lookup(&sctp_transport_hashtable, &arg,
+			       sctp_hash_params);
+
+	rhl_for_each_entry_rcu(transport, tmp, list, node)
+		if (transport->asoc->ep == t->asoc->ep) {
+			err = -EEXIST;
+			goto out;
+		}
+
 	err = rhltable_insert_key(&sctp_transport_hashtable, &arg,
 				  &t->node, sctp_hash_params);
+
+out:
 	if (err)
 		pr_err_once("insert transport fail, errno %d\n", err);
 
