Re: [ 102/184] Bluetooth: fix possible info leak in

[Ben Hutchings]

On Tue, 2013-06-04 at 19:23 +0200, Willy Tarreau wrote:
> 2.6.32-longterm review patch.  If anyone has any objections, please let me know.
> 
> ------------------
>  bt_sock_recvmsg()
> 
> From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

commit 4683f42fde3977bdb4e8a09622788cc8b5313778 upstream.

> In case the socket is already shutting down, bt_sock_recvmsg() returns
> with 0 without updating msg_namelen leading to net/socket.c leaking the
> local, uninitialized sockaddr_storage variable to userland -- 128 bytes
> of kernel stack memory.
> 
> Fix this by moving the msg_namelen assignment in front of the shutdown
> test.
> 
> Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
> Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx>
> Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> [dannf: adjusted to apply to Debian's 2.6.32]
> Signed-off-by: Willy Tarreau <w@xxxxxx>
> ---
>  net/bluetooth/af_bluetooth.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
> index 8cfb5a8..d7239dd 100644
> --- a/net/bluetooth/af_bluetooth.c
> +++ b/net/bluetooth/af_bluetooth.c
> @@ -240,14 +240,14 @@ int bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
>  	if (flags & (MSG_OOB))
>  		return -EOPNOTSUPP;
>  
> +	msg->msg_namelen = 0;
> +
>  	if (!(skb = skb_recv_datagram(sk, flags, noblock, &err))) {
>  		if (sk->sk_shutdown & RCV_SHUTDOWN)
>  			return 0;
>  		return err;
>  	}
>  
> -	msg->msg_namelen = 0;
> -
>  	copied = skb->len;
>  	if (len < copied) {
>  		msg->msg_flags |= MSG_TRUNC;

-- 
Ben Hutchings
Theory and practice are closer in theory than in practice.
                                - John Levine, moderator of comp.compilers

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