Commit cd2b7087 authored Feb 17, 2017 by Xin Long Committed by David S. Miller Feb 19, 2017

sctp: check duplicate node before inserting a new transport



sctp has changed to use rhlist for transport rhashtable since commit
7fda702f ("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: 7fda702f ("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>

parent 7e1392fb

net/sctp/input.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -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);

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