Bluetooth: Reject an encryption request when the key isn't found

Now that we have methods to finding keys by its parameters we can
reject an encryption request if the key isn't found.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/hci_event.c

@@ -2858,21 +2858,35 @@ static inline void hci_le_ltk_request_evt(struct hci_dev *hdev,
 {
 	struct hci_ev_le_ltk_req *ev = (void *) skb->data;
 	struct hci_cp_le_ltk_reply cp;
+	struct hci_cp_le_ltk_neg_reply neg;
 	struct hci_conn *conn;
+	struct link_key *ltk;
 
 	BT_DBG("%s handle %d", hdev->name, cpu_to_le16(ev->handle));
 
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(ev->handle));
+	if (conn == NULL)
+		goto not_found;
 
-	memset(&cp, 0, sizeof(cp));
+	ltk = hci_find_ltk(hdev, ev->ediv, ev->random);
+	if (ltk == NULL)
+		goto not_found;
+
+	memcpy(cp.ltk, ltk->val, sizeof(ltk->val));
 	cp.handle = cpu_to_le16(conn->handle);
-	memcpy(cp.ltk, conn->ltk, sizeof(conn->ltk));
 
 	hci_send_cmd(hdev, HCI_OP_LE_LTK_REPLY, sizeof(cp), &cp);
 
 	hci_dev_unlock(hdev);
+
+	return;
+
+not_found:
+	neg.handle = ev->handle;
+	hci_send_cmd(hdev, HCI_OP_LE_LTK_NEG_REPLY, sizeof(neg), &neg);
+	hci_dev_unlock(hdev);
 }
 
 static inline void hci_le_meta_evt(struct hci_dev *hdev, struct sk_buff *skb)