atm: fix info leak via getsockname()

[ Upstream commit 3c0c5cfd ]

The ATM code fails to initialize the two padding bytes of struct
sockaddr_atmpvc inserted for alignment. Add an explicit memset(0)
before filling the structure to avoid the info leak.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/atm/pvc.c

@@ -95,6 +95,7 @@ static int pvc_getname(struct socket *sock, struct sockaddr *sockaddr,
 		return -ENOTCONN;
 	*sockaddr_len = sizeof(struct sockaddr_atmpvc);
 	addr = (struct sockaddr_atmpvc *)sockaddr;
+	memset(addr, 0, sizeof(*addr));
 	addr->sap_family = AF_ATMPVC;
 	addr->sap_addr.itf = vcc->dev->number;
 	addr->sap_addr.vpi = vcc->vpi;