irda: Fix missing msg_namelen update in irda_recvmsg_dgram()

From: Mathias Krause <minipli@googlemail.com>

CVE-2013-3228

BugLink: https://bugs.launchpad.net/bugs/1172380

The current code does not fill the msg_name member in case it is set.
It also does not set the msg_namelen member to 0 and therefore makes
net/socket.c leak the local, uninitialized sockaddr_storage variable
to userland -- 128 bytes of kernel stack memory.

Fix that by simply setting msg_namelen to 0 as obviously nobody cared
about irda_recvmsg_dgram() not filling the msg_name in case it was
set.

Cc: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(back ported from commit 5ae94c0d2f0bed41d6718be743985d61b7f5c47d)

Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 net/irda/af_irda.c | 2 ++
 1 file changed, 2 insertions(+)

Great, I forgot to update the Subject: line with serie and CVE
number.


Cheers,
--
Luis

On Mon, May 20, 2013 at 01:06:21PM +0100, Luis Henriques wrote:
> From: Mathias Krause <minipli@googlemail.com>
> 
> CVE-2013-3228
> 
> BugLink: https://bugs.launchpad.net/bugs/1172380
> 
> The current code does not fill the msg_name member in case it is set.
> It also does not set the msg_namelen member to 0 and therefore makes
> net/socket.c leak the local, uninitialized sockaddr_storage variable
> to userland -- 128 bytes of kernel stack memory.
> 
> Fix that by simply setting msg_namelen to 0 as obviously nobody cared
> about irda_recvmsg_dgram() not filling the msg_name in case it was
> set.
> 
> Cc: Samuel Ortiz <samuel@sortiz.org>
> Signed-off-by: Mathias Krause <minipli@googlemail.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> (back ported from commit 5ae94c0d2f0bed41d6718be743985d61b7f5c47d)
> 
> Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
> ---
>  net/irda/af_irda.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
> index 476b24e..bfb325d 100644
> --- a/net/irda/af_irda.c
> +++ b/net/irda/af_irda.c
> @@ -1338,6 +1338,8 @@ static int irda_recvmsg_dgram(struct kiocb *iocb, struct socket *sock,
>  	if ((err = sock_error(sk)) < 0)
>  		return err;
>  
> +	msg->msg_namelen = 0;
> +
>  	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
>  				flags & MSG_DONTWAIT, &err);
>  	if (!skb)
> -- 
> 1.8.1.2
> 
> 
> -- 
> kernel-team mailing list
> kernel-team@lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team

On Mon, May 20, 2013 at 01:06:21PM +0100, Luis Henriques wrote:
> From: Mathias Krause <minipli@googlemail.com>
> 
> CVE-2013-3228
> 
> BugLink: https://bugs.launchpad.net/bugs/1172380
> 
> The current code does not fill the msg_name member in case it is set.
> It also does not set the msg_namelen member to 0 and therefore makes
> net/socket.c leak the local, uninitialized sockaddr_storage variable
> to userland -- 128 bytes of kernel stack memory.
> 
> Fix that by simply setting msg_namelen to 0 as obviously nobody cared
> about irda_recvmsg_dgram() not filling the msg_name in case it was
> set.
> 
> Cc: Samuel Ortiz <samuel@sortiz.org>
> Signed-off-by: Mathias Krause <minipli@googlemail.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> (back ported from commit 5ae94c0d2f0bed41d6718be743985d61b7f5c47d)
> 
> Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
> ---
>  net/irda/af_irda.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
> index 476b24e..bfb325d 100644
> --- a/net/irda/af_irda.c
> +++ b/net/irda/af_irda.c
> @@ -1338,6 +1338,8 @@ static int irda_recvmsg_dgram(struct kiocb *iocb, struct socket *sock,
>  	if ((err = sock_error(sk)) < 0)
>  		return err;
>  
> +	msg->msg_namelen = 0;
> +
>  	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
>  				flags & MSG_DONTWAIT, &err);
>  	if (!skb)

Looks to be a valid backport of the above commit id.  Looks to do what
is claimed.

Acked-by: Andy Whitcroft <apw@canonical.com>

-apw