af_key: fix info leaks in notify messages

key_notify_sa_flush() and key_notify_policy_flush() miss to initialize
the sadb_msg_reserved member of the broadcasted message and thereby
leak 2 bytes of heap memory to listeners. Fix that.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/key/af_key.c

@@ -1710,6 +1710,7 @@ static int key_notify_sa_flush(const struct km_event *c)
 	hdr->sadb_msg_version = PF_KEY_V2;
 	hdr->sadb_msg_errno = (uint8_t) 0;
 	hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
+	hdr->sadb_msg_reserved = 0;
 
 	pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
 
@@ -2699,6 +2700,7 @@ static int key_notify_policy_flush(const struct km_event *c)
 	hdr->sadb_msg_errno = (uint8_t) 0;
 	hdr->sadb_msg_satype = SADB_SATYPE_UNSPEC;
 	hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
+	hdr->sadb_msg_reserved = 0;
 	pfkey_broadcast(skb_out, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
 	return 0;