Re: [PATCH net] sctp: check duplicate node before inserting a new transport

[David Miller <davem@davemloft.net>]

From: Xin Long <lucien.xin@gmail.com>
Date: Fri, 17 Feb 2017 16:35:24 +0800

> sctp has changed to use rhlist for transport rhashtable since commit
> 7fda702f9315 ("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: 7fda702f9315 ("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>

Applied.