net: rose: restore old recvmsg behavior

recvmsg handler in net/rose/af_rose.c performs size-check ->msg_namelen.

After commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c
(net: rework recvmsg handler msg_name and msg_namelen logic), we now
always take the else branch due to namelen being initialized to 0.

Digging in netdev-vger-cvs git repo shows that msg_namelen was
initialized with a fixed-size since at least 1995, so the else branch
was never taken.

Compile tested only.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/rose/af_rose.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

On Mon, Dec 23, 2013 at 12:32:31AM +0100, Florian Westphal wrote:
> --- a/net/rose/af_rose.c
> +++ b/net/rose/af_rose.c
> @@ -1253,6 +1253,7 @@ static int rose_recvmsg(struct kiocb *iocb, struct socket *sock,
>  
>  	if (msg->msg_name) {
>  		struct sockaddr_rose *srose;
> +		struct full_sockaddr_rose *full_srose = msg->msg_name;
>  
>  		memset(msg->msg_name, 0, sizeof(struct full_sockaddr_rose));
>  		srose = msg->msg_name;
> @@ -1260,18 +1261,9 @@ static int rose_recvmsg(struct kiocb *iocb, struct socket *sock,
>  		srose->srose_addr   = rose->dest_addr;
>  		srose->srose_call   = rose->dest_call;
>  		srose->srose_ndigis = rose->dest_ndigis;
> -		if (msg->msg_namelen >= sizeof(struct full_sockaddr_rose)) {
> -			struct full_sockaddr_rose *full_srose = (struct full_sockaddr_rose *)msg->msg_name;
> -			for (n = 0 ; n < rose->dest_ndigis ; n++)
> -				full_srose->srose_digis[n] = rose->dest_digis[n];
> -			msg->msg_namelen = sizeof(struct full_sockaddr_rose);
> -		} else {
> -			if (rose->dest_ndigis >= 1) {
> -				srose->srose_ndigis = 1;
> -				srose->srose_digi = rose->dest_digis[0];
> -			}
> -			msg->msg_namelen = sizeof(struct sockaddr_rose);
> -		}
> +		for (n = 0 ; n < rose->dest_ndigis ; n++)
> +			full_srose->srose_digis[n] = rose->dest_digis[n];
> +		msg->msg_namelen = sizeof(struct full_sockaddr_rose);
>  	}
>  
>  	skb_free_datagram(sk, skb);

Looks good. I guess we want to push that to stable, too?

Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

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From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Mon, 23 Dec 2013 04:17:06 +0100

> Looks good. I guess we want to push that to stable, too?
> 
> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

Applied and queued up for -stable.
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