103 lines
2.6 KiB
C++
103 lines
2.6 KiB
C++
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/*
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*
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* Copyright (c) 2011-2016 The University of Waikato, Hamilton, New Zealand.
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* All rights reserved.
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*
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* This file is part of libprotoident.
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*
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* This code has been developed by the University of Waikato WAND
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* research group. For further information please see http://www.wand.net.nz/
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*
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* libprotoident is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* libprotoident is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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*/
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#include <string.h>
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#include "libprotoident.h"
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#include "proto_manager.h"
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#include "proto_common.h"
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static bool match_length_single(uint32_t payload, uint32_t len) {
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uint32_t statedlen;
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if (len == 2) {
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return true;
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}
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statedlen = (ntohl(payload) >> 16);
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if (statedlen < 1280) {
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if (statedlen != len - 2)
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return false;
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}
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return true;
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}
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static bool match_dns_tcp_length(lpi_data_t *data) {
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uint32_t id0, id1;
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if (data->payload_len[0] == 0 || data->payload_len[1] == 0)
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return false;
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if (data->server_port != 53 && data->client_port != 53)
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return false;
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if (!match_length_single(data->payload[0], data->payload_len[0]))
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return false;
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if (!match_length_single(data->payload[1], data->payload_len[1]))
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return false;
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if (data->payload_len[0] > 2 && data->payload_len[1] > 2) {
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id0 = (ntohl(data->payload[0]) & 0xffff);
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id1 = (ntohl(data->payload[1]) & 0xffff);
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if (id0 != id1)
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return false;
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}
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return true;
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}
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static bool match_tcp_dns(lpi_data_t *data, lpi_module_t *mod UNUSED) {
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if (match_dns(data))
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return true;
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if (match_dns_tcp_length(data))
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return true;
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return false;
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}
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static lpi_module_t lpi_dns = {
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LPI_PROTO_DNS,
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LPI_CATEGORY_SERVICES,
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"DNS_TCP",
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6, /* Not a high certainty */
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match_tcp_dns
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};
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void register_dns_tcp(LPIModuleMap *mod_map) {
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register_protocol(&lpi_dns, mod_map);
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}
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