net: fix infoleak in llc

The stack object “info” has a total size of 12 bytes. Its last byte
is padding which is not initialized and leaked via “put_cmsg”.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index b3c52e3..8ae3ed9 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -626,6 +626,7 @@
 	if (llc->cmsg_flags & LLC_CMSG_PKTINFO) {
 		struct llc_pktinfo info;
 
+		memset(&info, 0, sizeof(info));
 		info.lpi_ifindex = llc_sk(skb->sk)->dev->ifindex;
 		llc_pdu_decode_dsap(skb, &info.lpi_sap);
 		llc_pdu_decode_da(skb, info.lpi_mac);