Subject: Re: [PATCH v2] tipc: don't reject messages if reversal fails

From: Erik Hugne <[email-masked]>
Date: Fri, 10 Apr 2015 14:15:59 +0200

Please ignore this, i meant to send it only to tipc-discussion for review first..

//E

On Fri, Apr 10, 2015 at 01:58:18PM +0200, [email-masked] wrote:
> From: Erik Hugne <[email-masked]>
> 
> When we fail to deliver a message to a socket, it is subject to
> message reversal. If the call to tipc_msg_reverse fails, we are
> passing dnode uninitialized to tipc_link_xmit_skb which causes the
> packet to either be dropped, or sent out to a random link. In the
> worst case this leads to a link reset.
> We fix this by only transmitting the message if reversal succeded.
> Also, the redundant check for 'err' is removed, because if the message
> was not consumed, it will always be set.
> 
> Signed-off-by: Erik Hugne <[email-masked]>
> ---
> v2: err check fix according to comments from Billie Alsup
> 
>  net/tipc/socket.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index ee90d74..d215f73 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -1701,7 +1701,7 @@ static int tipc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
>  			atomic_add(truesize, dcnt);
>  		return 0;
>  	}
> -	if (!err || tipc_msg_reverse(tsk_own_node(tsk), skb, &dnode, -err))
> +	if (tipc_msg_reverse(tsk_own_node(tsk), skb, &dnode, -err))
>  		tipc_link_xmit_skb(net, skb, dnode, tsk->portid);
>  	return 0;
>  }
> -- 
> 2.1.4
>