atm: fix info leak in getsockopt(SO_ATMPVC)

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>
diff --git a/net/atm/common.c b/net/atm/common.c
index b4b44db..0c0ad93 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -812,6 +812,7 @@
 
 		if (!vcc->dev || !test_bit(ATM_VF_ADDR, &vcc->flags))
 			return -ENOTCONN;
+		memset(&pvc, 0, sizeof(pvc));
 		pvc.sap_family = AF_ATMPVC;
 		pvc.sap_addr.itf = vcc->dev->number;
 		pvc.sap_addr.vpi = vcc->vpi;