[NETLINK]: introduce NLA_BINARY type

This patch introduces a new NLA_BINARY attribute policy type with the
verification of simply checking the maximum length of the payload.

It also fixes a small typo in the example.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/attr.c

@@ -67,6 +67,11 @@ static int validate_nla(struct nlattr *nla, int maxtype,
 		}
 		break;
 
+	case NLA_BINARY:
+		if (pt->len && attrlen > pt->len)
+			return -ERANGE;
+		break;
+
 	default:
 		if (pt->len)
 			minlen = pt->len;