154 lines
4.0 KiB
C++
154 lines
4.0 KiB
C++
/*
|
|
*
|
|
* Copyright (c) 2011-2016 The University of Waikato, Hamilton, New Zealand.
|
|
* All rights reserved.
|
|
*
|
|
* This file is part of libprotoident.
|
|
*
|
|
* This code has been developed by the University of Waikato WAND
|
|
* research group. For further information please see http://www.wand.net.nz/
|
|
*
|
|
* libprotoident is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU Lesser General Public License as published by
|
|
* the Free Software Foundation; either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* libprotoident is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*
|
|
*/
|
|
|
|
#include <string.h>
|
|
|
|
#include "libprotoident.h"
|
|
#include "proto_manager.h"
|
|
#include "proto_common.h"
|
|
|
|
static inline bool match_ntp_request(uint32_t payload, uint32_t len) {
|
|
|
|
uint8_t first;
|
|
uint8_t *ptr;
|
|
uint8_t version;
|
|
|
|
if (len != 48 && len != 68 && len != 64)
|
|
return false;
|
|
|
|
ptr = (uint8_t *)&payload;
|
|
first = *ptr;
|
|
|
|
//first = (uint8_t) (payload);
|
|
|
|
version = (first & 0x38) >> 3;
|
|
|
|
if (version > 4 || version == 0)
|
|
return false;
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
static inline bool match_version0_request(uint32_t payload, uint32_t len) {
|
|
|
|
uint32_t secondbyte = 0;
|
|
|
|
if (len != 48)
|
|
return false;
|
|
|
|
/* Only supporting the 'clock good' status for now */
|
|
if (!MATCH(payload, 0x00, ANY, ANY, ANY))
|
|
return false;
|
|
|
|
secondbyte = ((ntohl(payload) >> 16) & 0xff);
|
|
if (secondbyte > 4)
|
|
return false;
|
|
return true;
|
|
|
|
|
|
}
|
|
|
|
static inline bool match_ntp_response(uint32_t payload, uint32_t len) {
|
|
|
|
uint8_t first;
|
|
uint8_t version;
|
|
uint8_t mode;
|
|
|
|
/* Server may not have replied */
|
|
if (len == 0)
|
|
return true;
|
|
|
|
first = (uint8_t) (payload);
|
|
|
|
version = (first & 0x38) >> 3;
|
|
mode = (first & 0x07);
|
|
|
|
if (version > 4 || version == 0)
|
|
return false;
|
|
if (mode == 3)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
static inline bool match_ntp(lpi_data_t *data, lpi_module_t *mod UNUSED) {
|
|
|
|
/* Force NTP to be on port 123 */
|
|
|
|
if (data->server_port != 123 && data->client_port != 123)
|
|
return false;
|
|
|
|
if (match_ntp_request(data->payload[0], data->payload_len[0])) {
|
|
if (match_ntp_response(data->payload[1], data->payload_len[1]))
|
|
return true;
|
|
}
|
|
|
|
if (match_ntp_request(data->payload[1], data->payload_len[1])) {
|
|
if (match_ntp_response(data->payload[0], data->payload_len[0]))
|
|
return true;
|
|
}
|
|
|
|
if (match_version0_request(data->payload[0], data->payload_len[0])) {
|
|
if (match_ntp_response(data->payload[1], data->payload_len[1]))
|
|
return true;
|
|
}
|
|
|
|
if (match_version0_request(data->payload[1], data->payload_len[1])) {
|
|
if (match_ntp_response(data->payload[0], data->payload_len[0]))
|
|
return true;
|
|
}
|
|
|
|
/* OK, turns out we can have NTP servers that keep sending responses
|
|
* without a specific request from the client */
|
|
if (match_ntp_response(data->payload[0], data->payload_len[0]) &&
|
|
data->payload_len[0] == 48 &&
|
|
data->payload_len[1] == 0) {
|
|
return true;
|
|
}
|
|
if (match_ntp_response(data->payload[1], data->payload_len[1]) &&
|
|
data->payload_len[1] == 48 &&
|
|
data->payload_len[0] == 0) {
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static lpi_module_t lpi_ntp = {
|
|
LPI_PROTO_UDP_NTP,
|
|
LPI_CATEGORY_SERVICES,
|
|
"NTP",
|
|
2,
|
|
match_ntp
|
|
};
|
|
|
|
void register_ntp(LPIModuleMap *mod_map) {
|
|
register_protocol(&lpi_ntp, mod_map);
|
|
}
|
|
|