epan/dissectors/packet-fortinet-sso.c

   1 /* packet-fortinet-sso.c
   2  * Routines for Fortinet Single Sign-On
   3  * Copyright 2020, Alexis La Goutte <alexis.lagoutte at gmail dot com>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  *
  11  * No spec/doc is available based on reverse/analysis of protocol...
  12  */
  13
  14 #include "config.h"
  15
  16 #include <epan/packet.h>
  17 #include <epan/addr_resolv.h>
  18
  19 #define UDP_FSSO        8002
  20
  21 void proto_register_fortinet_sso(void);
  22 void proto_reg_handoff_fortinet_sso(void);
  23
  24 static int proto_fortinet_sso;
  25 static int ett_fortinet_sso;
  26
  27 static int hf_fsso_length;
  28 static int hf_fsso_timestamp;
  29 static int hf_fsso_client_ip;
  30 static int hf_fsso_payload_length;
  31 static int hf_fsso_string;
  32 static int hf_fsso_domain;
  33 static int hf_fsso_user;
  34 static int hf_fsso_host;
  35 static int hf_fsso_version;
  36 static int hf_fsso_tsagent_number_port_range;
  37 static int hf_fsso_tsagent_port_range_min;
  38 static int hf_fsso_tsagent_port_range_max;
  39 static int hf_fsso_unknown;
  40 static int hf_fsso_unknown_ipv4;
  41
  42 static dissector_handle_t fortinet_sso_handle;
  43
  44 static int
  45 dissect_fortinet_sso(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  46 {
  47     proto_tree *ti;
  48     proto_tree *fsso_tree;
  49     uint32_t payload_length, client_ip;
  50     int string_length = -1;
  51     const char *string;
  52     int32_t len;
  53     int offset = 0;
  54
  55     col_set_str(pinfo->cinfo, COL_PROTOCOL, "FSSO");
  56     col_set_str(pinfo->cinfo, COL_INFO, "Fortinet Single Sign-On");
  57
  58     ti = proto_tree_add_item(tree, proto_fortinet_sso, tvb, 0, -1, ENC_NA);
  59     fsso_tree = proto_item_add_subtree(ti, ett_fortinet_sso);
  60
  61     proto_tree_add_item(fsso_tree, hf_fsso_length, tvb, offset, 2, ENC_BIG_ENDIAN);
  62     offset += 2;
  63
  64     proto_tree_add_item(fsso_tree, hf_fsso_timestamp, tvb, offset, 4, ENC_BIG_ENDIAN);
  65     offset += 4;
  66
  67     proto_tree_add_item(fsso_tree, hf_fsso_client_ip, tvb, offset, 4, ENC_BIG_ENDIAN);
  68     client_ip = tvb_get_ipv4(tvb, offset);
  69     offset += 4;
  70
  71     proto_tree_add_item_ret_uint(fsso_tree, hf_fsso_payload_length, tvb, offset, 2, ENC_BIG_ENDIAN, &payload_length);
  72     offset += 2;
  73
  74     string = tvb_get_stringz_enc(pinfo->pool, tvb, offset, &string_length, ENC_ASCII);
  75     proto_tree_add_item(fsso_tree, hf_fsso_string, tvb, offset, string_length, ENC_ASCII);
  76     col_set_str(pinfo->cinfo, COL_INFO, string);
  77
  78     if(client_ip == 0xFFFFFFFF) { //if client_ip equal 255.255.255.255 (0xFFFFFFFF) is KeepAlive packet
  79         /* Domain / KeepAlive (User) / Version */
  80         len = tvb_find_uint8(tvb, offset, string_length, '/') - offset;
  81         proto_tree_add_item(fsso_tree, hf_fsso_domain, tvb, offset, len, ENC_ASCII);
  82         offset += (len + 1);
  83         string_length -= (len + 1);
  84
  85         len = tvb_find_uint8(tvb, offset, string_length, '/') - offset;
  86         proto_tree_add_item(fsso_tree, hf_fsso_user, tvb, offset, len, ENC_ASCII);
  87         offset += (len + 1);
  88         string_length -= (len + 1);
  89
  90         proto_tree_add_item(fsso_tree, hf_fsso_version, tvb, offset, string_length, ENC_ASCII);
  91         offset += (string_length);
  92
  93     } else {
  94         /* Host / Domain / User */
  95         len = tvb_find_uint8(tvb, offset, string_length, '/') - offset;
  96         proto_tree_add_item(fsso_tree, hf_fsso_host, tvb, offset, len, ENC_ASCII);
  97         offset += (len + 1);
  98         string_length -= (len + 1);
  99
 100         len = tvb_find_uint8(tvb, offset, string_length, '/') - offset;
 101         proto_tree_add_item(fsso_tree, hf_fsso_domain, tvb, offset, len, ENC_ASCII);
 102         offset += (len + 1);
 103         string_length -= (len + 1);
 104
 105         proto_tree_add_item(fsso_tree, hf_fsso_user, tvb, offset, string_length, ENC_ASCII);
 106         offset += (string_length);
 107     }
 108
 109     if(tvb_reported_length_remaining(tvb, offset) == 4) {
 110
 111         /* There is some packet with extra IPv4 address... */
 112         proto_tree_add_item(fsso_tree, hf_fsso_unknown_ipv4, tvb, offset, 4, ENC_NA);
 113         offset += 4;
 114
 115     } else {
 116
 117         if(tvb_reported_length_remaining(tvb, offset)) {
 118             uint16_t value;
 119             uint32_t number_port_range;
 120             value = tvb_get_ntohs(tvb, offset);
 121
 122             if(value == 0x2002) { /* Not a TS Agent additional Data */
 123                 proto_tree_add_item(fsso_tree, hf_fsso_unknown, tvb, offset, 2, ENC_NA);
 124                 offset += 2;
 125
 126                 proto_tree_add_item(fsso_tree, hf_fsso_unknown_ipv4, tvb, offset, 4, ENC_NA);
 127                 offset += 4;
 128
 129                 proto_tree_add_item(fsso_tree, hf_fsso_unknown, tvb, offset, 6, ENC_NA);
 130                 offset += 6;
 131
 132                 proto_tree_add_item(fsso_tree, hf_fsso_unknown_ipv4, tvb, offset, 4, ENC_NA);
 133                 offset += 4;
 134
 135                 proto_tree_add_item(fsso_tree, hf_fsso_unknown, tvb, offset, 1, ENC_NA);
 136                 offset += 1;
 137             } else {
 138                 proto_tree_add_item(fsso_tree, hf_fsso_unknown, tvb, offset, 15, ENC_NA);
 139                 offset += 15;
 140
 141                 proto_tree_add_item(fsso_tree, hf_fsso_unknown, tvb, offset, 5, ENC_NA);
 142                 offset += 5;
 143
 144                 proto_tree_add_item(fsso_tree, hf_fsso_unknown, tvb, offset, 6, ENC_NA);
 145                 offset += 6;
 146
 147                 /* Port Range assigned to user for TS Agent (RDP/Citrix) */
 148                 proto_tree_add_item_ret_uint(fsso_tree, hf_fsso_tsagent_number_port_range, tvb, offset, 2, ENC_BIG_ENDIAN, &number_port_range);
 149                 offset += 2;
 150
 151                 while (number_port_range) {
 152
 153                     proto_tree_add_item(fsso_tree, hf_fsso_tsagent_port_range_min, tvb, offset, 2, ENC_BIG_ENDIAN);
 154                     offset += 2;
 155
 156                     proto_tree_add_item(fsso_tree, hf_fsso_tsagent_port_range_max, tvb, offset, 2, ENC_BIG_ENDIAN);
 157                     offset += 2;
 158
 159                     number_port_range --;
 160                 }
 161             }
 162         }
 163
 164     }
 165
 166     return offset;
 167 }
 168
 169 static bool
 170 dissect_fortinet_fsso_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 171 {
 172     uint32_t length_remaining, length;
 173
 174     if (tvb_captured_length(tvb) < 2) {
 175         return false;
 176     }
 177
 178     length_remaining = tvb_reported_length_remaining(tvb, 0);
 179     //first bytes is the length of payload
 180     length = tvb_get_ntohs(tvb, 0);
 181     if(length_remaining != length)
 182     {
 183         return false;
 184     }
 185
 186     //always send with UDP Destination Port 80002
 187     if(pinfo->destport != UDP_FSSO)
 188     {
 189         return false;
 190     }
 191
 192     dissect_fortinet_sso(tvb, pinfo, tree, data);
 193     return true;
 194 }
 195
 196 void
 197 proto_register_fortinet_sso(void)
 198 {
 199     static hf_register_info hf[] = {
 200         { &hf_fsso_length,
 201         { "Length", "fortinet_sso.length", FT_UINT16, BASE_DEC, NULL, 0x0,
 202         NULL, HFILL}},
 203
 204         { &hf_fsso_timestamp,
 205         { "Timestamp", "fortinet_sso.timestamp", FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0,
 206         NULL, HFILL}},
 207
 208         { &hf_fsso_client_ip,
 209         { "Client IP", "fortinet_sso.client_ip", FT_IPv4, BASE_NONE, NULL, 0x0,
 210         NULL, HFILL}},
 211
 212         { &hf_fsso_payload_length,
 213         { "Payload Length", "fortinet_sso.payload_length", FT_UINT16, BASE_DEC, NULL, 0x0,
 214         NULL, HFILL}},
 215
 216         { &hf_fsso_string,
 217         { "String", "fortinet_sso.string", FT_STRING, BASE_NONE, NULL, 0x0,
 218         NULL, HFILL}},
 219
 220         { &hf_fsso_user,
 221         { "User", "fortinet_sso.user", FT_STRING, BASE_NONE, NULL, 0x0,
 222         NULL, HFILL}},
 223
 224         { &hf_fsso_domain,
 225         { "Domain", "fortinet_sso.domain", FT_STRING, BASE_NONE, NULL, 0x0,
 226         NULL, HFILL}},
 227
 228         { &hf_fsso_host,
 229         { "Host", "fortinet_sso.host", FT_STRING, BASE_NONE, NULL, 0x0,
 230         NULL, HFILL}},
 231
 232         { &hf_fsso_version,
 233         { "Version", "fortinet_sso.version", FT_STRING, BASE_NONE, NULL, 0x0,
 234         NULL, HFILL}},
 235
 236         { &hf_fsso_tsagent_number_port_range,
 237         { "Number of Port Range", "fortinet_sso.tsagent.port_range.number", FT_UINT16, BASE_DEC, NULL, 0x0,
 238         NULL, HFILL}},
 239
 240         { &hf_fsso_tsagent_port_range_min,
 241         { "Port Range (Min)", "fortinet_sso.tsagent.port_range.min", FT_UINT16, BASE_DEC, NULL, 0x0,
 242         NULL, HFILL}},
 243
 244         { &hf_fsso_tsagent_port_range_max,
 245         { "Port Range (Max)", "fortinet_sso.tsagent.port_range.max", FT_UINT16, BASE_DEC, NULL, 0x0,
 246         NULL, HFILL}},
 247
 248         { &hf_fsso_unknown,
 249         { "Unknown", "fortinet_sso.unknown", FT_BYTES, BASE_NONE, NULL, 0x0,
 250         "Unknown Data...", HFILL}},
 251
 252         { &hf_fsso_unknown_ipv4,
 253         { "Unknown IPv4", "fortinet_sso.unknown.ipv4", FT_IPv4, BASE_NONE, NULL, 0x0,
 254         "Unknown Data...", HFILL}},
 255
 256     };
 257
 258     static int *ett[] = {
 259         &ett_fortinet_sso,
 260     };
 261
 262     proto_fortinet_sso = proto_register_protocol("Fortinet Single Sign On", "fortinet_sso", "fortinet_sso");
 263     fortinet_sso_handle = register_dissector("fortinet_sso", dissect_fortinet_sso, proto_fortinet_sso);
 264
 265     proto_register_field_array(proto_fortinet_sso, hf, array_length(hf));
 266     proto_register_subtree_array(ett, array_length(ett));
 267 }
 268
 269
 270 void
 271 proto_reg_handoff_fortinet_sso(void)
 272 {
 273     dissector_add_uint_with_preference("udp.port", 0, fortinet_sso_handle);
 274     heur_dissector_add("udp", dissect_fortinet_fsso_heur, "Fortinet SSO over UDP", "fortinet_sso", proto_fortinet_sso, HEURISTIC_ENABLE);
 275 }
 276
 277 /*
 278  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 279  *
 280  * Local variables:
 281  * c-basic-offset: 4
 282  * tab-width: 8
 283  * indent-tabs-mode: nil
 284  * End:
 285  *
 286  * vi: set shiftwidth=4 tabstop=8 expandtab:
 287  * :indentSize=4:tabSize=8:noTabs=true:
 288  */