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Improved IPSec/ISAKMP detection. (#1600)
Signed-off-by: lns <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,198 @@ | ||
| /* | ||
| * ipsec.c | ||
| * | ||
| * Copyright (C) 2022 - ntop.org | ||
| * | ||
| * nDPI 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. | ||
| * | ||
| * nDPI 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 nDPI. If not, see <http://www.gnu.org/licenses/>. | ||
| * | ||
| */ | ||
|
|
||
| #include "ndpi_protocol_ids.h" | ||
|
|
||
| #define NDPI_CURRENT_PROTO NDPI_PROTOCOL_IPSEC | ||
|
|
||
| #include "ndpi_api.h" | ||
|
|
||
| enum isakmp_type { | ||
| ISAKMP_INVALID = 0, | ||
| ISAKMP_MALFORMED, | ||
| ISAKMP_V1, | ||
| ISAKMP_V2, | ||
| }; | ||
|
|
||
| static void ndpi_int_ipsec_add_connection(struct ndpi_detection_module_struct * const ndpi_struct, | ||
| struct ndpi_flow_struct * const flow, | ||
| enum isakmp_type isakmp_type) | ||
| { | ||
| switch (isakmp_type) | ||
| { | ||
| case ISAKMP_INVALID: | ||
| NDPI_EXCLUDE_PROTO(ndpi_struct, flow); | ||
| return; | ||
| case ISAKMP_MALFORMED: | ||
| NDPI_LOG_INFO(ndpi_struct, "found malformed ISAKMP (UDP)\n"); | ||
| ndpi_set_risk(ndpi_struct, flow, NDPI_MALFORMED_PACKET, "Invalid IPSec/ISAKMP Header"); | ||
| break; | ||
| case ISAKMP_V1: | ||
| NDPI_LOG_INFO(ndpi_struct, "found ISAKMPv1 (UDP)\n"); | ||
| break; | ||
| case ISAKMP_V2: | ||
| NDPI_LOG_INFO(ndpi_struct, "found ISAKMPv2 (UDP)\n"); | ||
| break; | ||
| } | ||
|
|
||
| ndpi_set_detected_protocol(ndpi_struct, flow, | ||
| NDPI_PROTOCOL_IPSEC, | ||
| NDPI_PROTOCOL_UNKNOWN, | ||
| NDPI_CONFIDENCE_DPI); | ||
| } | ||
|
|
||
| static enum isakmp_type ndpi_int_check_ports(struct ndpi_packet_struct const * const packet) | ||
| { | ||
| u_int16_t sport = ntohs(packet->udp->source); | ||
| u_int16_t dport = ntohs(packet->udp->dest); | ||
|
|
||
| /* | ||
| * If packet matches default IPSec/ISAKMP ports, it is most likely malformed, | ||
| * not IPSec/ISAKMP otherwise. | ||
| */ | ||
| if (sport == 500 || dport == 500 || | ||
| sport == 4500 || dport == 4500) | ||
| { | ||
| return ISAKMP_MALFORMED; | ||
| } | ||
|
|
||
| return ISAKMP_INVALID; | ||
| } | ||
|
|
||
| static enum isakmp_type ndpi_int_check_isakmp_v1(struct ndpi_packet_struct const * const packet, | ||
| u_int16_t isakmp_offset, enum isakmp_type isakmp_type) | ||
| { | ||
| /* Next payload type */ | ||
| if (packet->payload[isakmp_offset + 16] >= 14 && packet->payload[isakmp_offset + 16] <= 127) | ||
| { | ||
| return ndpi_int_check_ports(packet); | ||
| } | ||
|
|
||
| /* Exchange Type */ | ||
| if (packet->payload[isakmp_offset + 18] >= 6 && packet->payload[isakmp_offset + 18] < 31) | ||
| { | ||
| return ndpi_int_check_ports(packet); | ||
| } | ||
|
|
||
| /* Flags */ | ||
| if (packet->payload[isakmp_offset + 19] >= 8) | ||
| { | ||
| return ndpi_int_check_ports(packet); | ||
| } | ||
|
|
||
| return isakmp_type; | ||
| } | ||
|
|
||
| static enum isakmp_type ndpi_int_check_isakmp_v2(struct ndpi_packet_struct const * const packet, | ||
| u_int16_t isakmp_offset, enum isakmp_type isakmp_type) | ||
| { | ||
| /* Next payload type */ | ||
| if ((packet->payload[isakmp_offset + 16] > 0 && packet->payload[isakmp_offset + 16] <= 32) || | ||
| (packet->payload[isakmp_offset + 16] >= 49 && packet->payload[isakmp_offset + 16] <= 127)) | ||
| { | ||
| return ndpi_int_check_ports(packet); | ||
| } | ||
|
|
||
| /* Exchange Type */ | ||
| if ((packet->payload[isakmp_offset + 18] <= 33) || | ||
| (packet->payload[isakmp_offset + 18] >= 38 && packet->payload[isakmp_offset + 18] <= 239)) | ||
| { | ||
| return ndpi_int_check_ports(packet); | ||
| } | ||
|
|
||
| /* Flags */ | ||
| if ((packet->payload[isakmp_offset + 19] & 0xC7) != 0) | ||
| { | ||
| return ndpi_int_check_ports(packet); | ||
| } | ||
|
|
||
| return isakmp_type; | ||
| } | ||
|
|
||
| void ndpi_search_ipsec(struct ndpi_detection_module_struct *ndpi_struct, | ||
| struct ndpi_flow_struct *flow) | ||
| { | ||
| struct ndpi_packet_struct * const packet = &ndpi_struct->packet; | ||
| u_int16_t isakmp_offset = 0; | ||
| enum isakmp_type isakmp_type = ISAKMP_INVALID; | ||
|
|
||
| NDPI_LOG_DBG(ndpi_struct, "search IPSEC (UDP)\n"); | ||
|
|
||
| if (packet->payload_packet_len < 28) | ||
| { | ||
| NDPI_EXCLUDE_PROTO(ndpi_struct, flow); | ||
| return; | ||
| } | ||
|
|
||
| /* check for non-ESP marker required for ISAKMP over UDP */ | ||
| if (get_u_int32_t(packet->payload, 0) == 0x00000000) | ||
| { | ||
| isakmp_offset = 4; | ||
| if (packet->payload_packet_len < 32) | ||
| { | ||
| NDPI_EXCLUDE_PROTO(ndpi_struct, flow); | ||
| return; | ||
| } | ||
| } | ||
|
|
||
| if (packet->payload[isakmp_offset + 17] != 0x20 /* Major Version 2 */) | ||
| { | ||
| if (packet->payload[isakmp_offset + 17] != 0x10 /* Major Version 1 */) | ||
| { | ||
| NDPI_EXCLUDE_PROTO(ndpi_struct, flow); | ||
| return; | ||
| } else { | ||
| /* Version 1 is obsolete, but still used by some embedded devices. */ | ||
| isakmp_type = ISAKMP_V1; | ||
| } | ||
| } else { | ||
| isakmp_type = ISAKMP_V2; | ||
| } | ||
|
|
||
| if (ntohl(get_u_int32_t(packet->payload, isakmp_offset + 24)) != (u_int32_t)packet->payload_packet_len - isakmp_offset) | ||
| { | ||
| NDPI_EXCLUDE_PROTO(ndpi_struct, flow); | ||
| return; | ||
| } | ||
|
|
||
| if (isakmp_type == ISAKMP_V1) | ||
| { | ||
| isakmp_type = ndpi_int_check_isakmp_v1(packet, isakmp_offset, isakmp_type); | ||
| } else { | ||
| isakmp_type = ndpi_int_check_isakmp_v2(packet, isakmp_offset, isakmp_type); | ||
| } | ||
|
|
||
| ndpi_int_ipsec_add_connection(ndpi_struct, flow, isakmp_type); | ||
| } | ||
|
|
||
| void init_ipsec_dissector(struct ndpi_detection_module_struct *ndpi_struct, | ||
| u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask) | ||
| { | ||
| ndpi_set_bitmask_protocol_detection("IPSec", ndpi_struct, detection_bitmask, *id, | ||
| NDPI_PROTOCOL_IPSEC, | ||
| ndpi_search_ipsec, | ||
| NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD, | ||
| SAVE_DETECTION_BITMASK_AS_UNKNOWN, | ||
| ADD_TO_DETECTION_BITMASK | ||
| ); | ||
|
|
||
| *id += 1; | ||
| } | ||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,11 +1,10 @@ | ||
| Guessed flow protos: 1 | ||
| Guessed flow protos: 0 | ||
|
|
||
| DPI Packets (UDP): 4 (4.00 pkts/flow) | ||
| DPI Packets (UDP): 1 (1.00 pkts/flow) | ||
| DPI Packets (other): 1 (1.00 pkts/flow) | ||
| Confidence Match by port : 1 (flows) | ||
| Confidence DPI : 1 (flows) | ||
| Confidence DPI : 2 (flows) | ||
|
|
||
| IPsec 6 1768 2 | ||
| IPSec 6 1768 2 | ||
|
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||
| 1 UDP 10.2.3.2:500 <-> 10.3.4.4:500 [proto: 79/IPsec][Encrypted][Confidence: Match by port][cat: VPN/2][2 pkts/770 bytes <-> 2 pkts/722 bytes][Goodput ratio: 89/88][0.02 sec][PLAIN TEXT (DELETE)][Plen Bins: 0,0,0,0,0,0,0,0,25,0,25,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] | ||
| 2 51 10.2.3.2:0 <-> 10.3.4.4:0 [proto: 79/IPsec][Encrypted][Confidence: DPI][cat: VPN/2][1 pkts/138 bytes <-> 1 pkts/138 bytes][Goodput ratio: 0/0][< 1 sec][Plen Bins: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] | ||
| 1 UDP 10.2.3.2:500 <-> 10.3.4.4:500 [proto: 79/IPSec][Encrypted][Confidence: DPI][cat: VPN/2][2 pkts/770 bytes <-> 2 pkts/722 bytes][Goodput ratio: 89/88][0.02 sec][PLAIN TEXT (DELETE)][Plen Bins: 0,0,0,0,0,0,0,0,25,0,25,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] | ||
| 2 51 10.2.3.2:0 <-> 10.3.4.4:0 [proto: 79/IPSec][Encrypted][Confidence: DPI][cat: VPN/2][1 pkts/138 bytes <-> 1 pkts/138 bytes][Goodput ratio: 0/0][< 1 sec][Plen Bins: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,11 +1,10 @@ | ||
| Guessed flow protos: 1 | ||
| Guessed flow protos: 0 | ||
|
|
||
| DPI Packets (UDP): 4 (4.00 pkts/flow) | ||
| DPI Packets (UDP): 1 (1.00 pkts/flow) | ||
| DPI Packets (other): 1 (1.00 pkts/flow) | ||
| Confidence Match by port : 1 (flows) | ||
| Confidence DPI : 1 (flows) | ||
| Confidence DPI : 2 (flows) | ||
|
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| IPsec 6 1856 2 | ||
| IPSec 6 1856 2 | ||
|
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| 1 UDP 10.2.3.2:500 <-> 10.3.4.4:500 [proto: 79/IPsec][Encrypted][Confidence: Match by port][cat: VPN/2][2 pkts/786 bytes <-> 2 pkts/738 bytes][Goodput ratio: 89/88][0.02 sec][PLAIN TEXT (DELETE)][Plen Bins: 0,0,0,0,0,0,0,0,0,25,25,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] | ||
| 2 50 10.2.3.2:0 <-> 10.3.4.4:0 [proto: 79/IPsec][Encrypted][Confidence: DPI][cat: VPN/2][1 pkts/166 bytes <-> 1 pkts/166 bytes][Goodput ratio: 0/0][0.00 sec][Plen Bins: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] | ||
| 1 UDP 10.2.3.2:500 <-> 10.3.4.4:500 [proto: 79/IPSec][Encrypted][Confidence: DPI][cat: VPN/2][2 pkts/786 bytes <-> 2 pkts/738 bytes][Goodput ratio: 89/88][0.02 sec][PLAIN TEXT (DELETE)][Plen Bins: 0,0,0,0,0,0,0,0,0,25,25,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] | ||
| 2 50 10.2.3.2:0 <-> 10.3.4.4:0 [proto: 79/IPSec][Encrypted][Confidence: DPI][cat: VPN/2][1 pkts/166 bytes <-> 1 pkts/166 bytes][Goodput ratio: 0/0][0.00 sec][Plen Bins: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] |
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