netdev - Re: [PATCH] sctp: Use correct sideffect command in duplicate cookie handling

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Message-ID: <20130313132913.GB17592@hmsreliant.think-freely.org>
Date:	Wed, 13 Mar 2013 09:29:13 -0400
From:	Neil Horman <nhorman@...driver.com>
To:	Vlad Yasevich <vyasevich@...il.com>
Cc:	netdev@...r.kernel.org, linux-sctp@...r.kernel.org
Subject: Re: [PATCH] sctp: Use correct sideffect command in duplicate cookie
 handling

On Tue, Mar 12, 2013 at 09:53:23PM -0400, Vlad Yasevich wrote:
> When SCTP is done processing a duplicate cookie chunk, it tries
> to delete a newly created association.  For that, it has to set
> the right association for the side-effect processing to work.
> However, when it uses the SCTP_CMD_NEW_ASOC command, that performs
> more work then really needed (like hashing the associationa and
> assigning it an id) and there is no point to do that only to
> delete the association as a next step.  In fact, it also creates
> an impossible condition where an association may be found by
> the getsockopt() call, and that association is empty.  This
> causes a crash in some sctp getsockopts.
> 
> The solution is rather simple.  We simply use SCTP_CMD_SET_ASOC
> command that doesn't have all the overhead and does exactly
> what we need.
> 
> Reported-by: Karl Heiss <kheiss@...il.com>
> Tested-by: Karl Heiss <kheiss@...il.com>
> CC: Neil Horman <nhorman@...driver.com>
> Signed-off-by: Vlad Yasevich <vyasevich@...il.com>
> ---
>  net/sctp/sm_statefuns.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index 5131fcf..de1a013 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -2082,7 +2082,7 @@ sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
>  	}
>  
>  	/* Delete the tempory new association. */
> -	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
> +	sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
>  	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
>  
>  	/* Restore association pointer to provide SCTP command interpeter
> -- 
> 1.7.7.6
> 
> 
Acked-by: Neil Horman <nhorman@...driver.com>

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