Re: [ 080/143] net: rework recvmsg handler msg_name and msg_namelen logic

[Luis Henriques]

 On Mon, May 12, 2014 at 02:33:20AM +0200, Willy Tarreau wrote:
> 2.6.32-longterm review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
> 
> [ Upstream commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c ]
> 

<snip>

> diff --git a/net/rxrpc/ar-recvmsg.c b/net/rxrpc/ar-recvmsg.c
> index a39bf97..f779fc3 100644
> --- a/net/rxrpc/ar-recvmsg.c
> +++ b/net/rxrpc/ar-recvmsg.c
> @@ -142,10 +142,12 @@ int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock,
>  
>  		/* copy the peer address and timestamp */
>  		if (!continue_call) {
> -			if (msg->msg_name && msg->msg_namelen > 0)
> +			if (msg->msg_name) {
> +				size_t len =
> +					sizeof(call->conn->trans->peer->srx);
>  				memcpy(msg->msg_name,
> -				       &call->conn->trans->peer->srx,
> -				       sizeof(call->conn->trans->peer->srx));
> +				       &call->conn->trans->peer->srx, len);
  +                                    msg->msg_namelen = len;

This statement^^^ is missing in this backport.

Also missing in this patch are the changes to the following functions:

- pppoe_recvmsg()
  In file drivers/net/pppoe.c instead of drivers/net/ppp/pppoe.c

- pppol2tp_recvmsg()
  In file drivers/net/pppol2tp.c instead of net/l2tp/l2tp_ppp.c

For reference, I'm attaching the backport we have used in our Ubuntu
kernel.  (Note that we added some extra information to the commit
message to include the CVE number and a link to the CVE bug.)

Cheers,
--
Luís