Subject: Re: [PATCH net] sctp: use right member as the param of list_for_each_entry

From: Marcelo Ricardo Leitner <[email-masked]>
Date: Mon, 27 Nov 2017 10:45:36 -0200

On Sun, Nov 26, 2017 at 08:56:07PM +0800, Xin Long wrote:
> Commit d04adf1b3551 ("sctp: reset owner sk for data chunks on out queues
> when migrating a sock") made a mistake that using 'list' as the param of
> list_for_each_entry to traverse the retransmit, sacked and abandoned
> queues, while chunks are using 'transmitted_list' to link into these
> queues.
> 
> It could cause NULL dereference panic if there are chunks in any of these
> queues when peeling off one asoc.
> 
> So use the chunk member 'transmitted_list' instead in this patch.
> 
> Fixes: d04adf1b3551 ("sctp: reset owner sk for data chunks on out queues when migrating a sock")
> Signed-off-by: Xin Long <[email-masked]>

Ouch

Acked-by: Marcelo Ricardo Leitner <[email-masked]>

> ---
>  net/sctp/socket.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 3204a9b..014847e 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -188,13 +188,13 @@ static void sctp_for_each_tx_datachunk(struct sctp_association *asoc,
>  		list_for_each_entry(chunk, &t->transmitted, transmitted_list)
>  			cb(chunk);
>  
> -	list_for_each_entry(chunk, &q->retransmit, list)
> +	list_for_each_entry(chunk, &q->retransmit, transmitted_list)
>  		cb(chunk);
>  
> -	list_for_each_entry(chunk, &q->sacked, list)
> +	list_for_each_entry(chunk, &q->sacked, transmitted_list)
>  		cb(chunk);
>  
> -	list_for_each_entry(chunk, &q->abandoned, list)
> +	list_for_each_entry(chunk, &q->abandoned, transmitted_list)
>  		cb(chunk);
>  
>  	list_for_each_entry(chunk, &q->out_chunk_list, list)
> -- 
> 2.1.0
> 
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