| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: packet-tripe.c,v 1.3 2004/04/08 01:36:17 mdw Exp $ |
| 4 | * |
| 5 | * TrIPE protocol dissector for Ethereal |
| 6 | * |
| 7 | * (c) 2003 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Trivial IP Encryption (TrIPE). |
| 13 | * |
| 14 | * TrIPE is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2 of the License, or |
| 17 | * (at your option) any later version. |
| 18 | * |
| 19 | * TrIPE is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with TrIPE; if not, write to the Free Software Foundation, |
| 26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Header files ------------------------------------------------------*/ |
| 30 | |
| 31 | #include "config.h" |
| 32 | |
| 33 | #include <stdio.h> |
| 34 | #include <stdlib.h> |
| 35 | #include <string.h> |
| 36 | |
| 37 | #include <netinet/in.h> |
| 38 | |
| 39 | #include <glib.h> |
| 40 | #include <gmodule.h> |
| 41 | #include <epan/packet.h> |
| 42 | |
| 43 | #ifdef ETHEREAL_BUGGERED |
| 44 | # define plugin_address_table_t void |
| 45 | # define plugin_address_table_init(x) |
| 46 | #else |
| 47 | # include <plugins/plugin_api.h> |
| 48 | #endif |
| 49 | |
| 50 | #include "tripe-protocol.h" |
| 51 | |
| 52 | /*----- Static variables --------------------------------------------------*/ |
| 53 | |
| 54 | static int proto_tripe = -1; |
| 55 | |
| 56 | typedef struct hfmp { |
| 57 | int hf, hf_len, hf_val, tt; |
| 58 | } hfmp; |
| 59 | typedef struct hfge { |
| 60 | int hf, hf_len, hf_val, hfx_len, hfx_val, hfy_len, hfy_val, tt; |
| 61 | } hfge; |
| 62 | |
| 63 | static int hf_tripe_cat = -1; |
| 64 | static int hf_tripe_packet_type = -1; |
| 65 | static int hf_tripe_ct = -1; |
| 66 | static int hf_tripe_ct_seq = -1; |
| 67 | static int hf_tripe_ct_iv = -1; |
| 68 | static int hf_tripe_ct_cbc = -1; |
| 69 | static int hf_tripe_ct_mac = -1; |
| 70 | static int hf_tripe_kx_type = -1; |
| 71 | static hfge hf_tripe_kx_mychal = { -1, -1, -1, -1, -1, -1, -1, -1 }; |
| 72 | static int hf_tripe_kx_mycookie = -1; |
| 73 | static int hf_tripe_kx_yourcookie = -1; |
| 74 | static hfmp hf_tripe_kx_check = { -1, -1, -1, -1 }; |
| 75 | static int hf_tripe_huh = -1; |
| 76 | |
| 77 | static int tt_tripe = -1; |
| 78 | static int tt_tripe_ct = -1; |
| 79 | |
| 80 | G_MODULE_EXPORT const gchar version[] = VERSION; |
| 81 | |
| 82 | /*----- Main code ---------------------------------------------------------*/ |
| 83 | |
| 84 | static gint gethash(proto_tree *tt, int hf, tvbuff_t *b, gint off) |
| 85 | { |
| 86 | proto_tree_add_item(tt, hf, b, off, 20, FALSE); |
| 87 | return (off + 20); |
| 88 | } |
| 89 | |
| 90 | static gint getmp(proto_tree *tt, const hfmp *hf, tvbuff_t *b, gint off) |
| 91 | { |
| 92 | guint16 len = tvb_get_ntohs(b, off); |
| 93 | proto_item *ti = proto_tree_add_item(tt, hf->hf, b, off, len + 2, FALSE); |
| 94 | tt = proto_item_add_subtree(ti, hf->tt); |
| 95 | proto_tree_add_item(tt, hf->hf_len, b, off, 2, FALSE); |
| 96 | proto_tree_add_item(tt, hf->hf_val, b, off + 2, len, FALSE); |
| 97 | return (off + 2 + len); |
| 98 | } |
| 99 | |
| 100 | static gint getge(proto_tree *tt, const hfge *hf, tvbuff_t *b, gint off) |
| 101 | { |
| 102 | guint16 len = tvb_get_ntohs(b, off), len2; |
| 103 | guint r; |
| 104 | proto_item *ti; |
| 105 | r = tvb_length_remaining(b, off); |
| 106 | if (r < 4 + len || |
| 107 | (len2 = tvb_get_ntohs(b, off + 2 + len), r < 4 + len + len2)) { |
| 108 | ti = proto_tree_add_item(tt, hf->hf, b, off, len + 2, FALSE); |
| 109 | tt = proto_item_add_subtree(ti, hf->tt); |
| 110 | proto_tree_add_item(tt, hf->hf_len, b, off, 2, FALSE); |
| 111 | proto_tree_add_item(tt, hf->hf_val, b, off + 2, len, FALSE); |
| 112 | r = off + len + 2; |
| 113 | } else { |
| 114 | ti = proto_tree_add_item(tt, hf->hf, b, off, len + len2 + 4, FALSE); |
| 115 | tt = proto_item_add_subtree(ti, hf->tt); |
| 116 | proto_tree_add_item(tt, hf->hfx_len, b, off, 2, FALSE); |
| 117 | proto_tree_add_item(tt, hf->hfx_val, b, off + 2, len, FALSE); |
| 118 | proto_tree_add_item(tt, hf->hfy_len, b, off + 2 + len, 2, FALSE); |
| 119 | proto_tree_add_item(tt, hf->hfy_val, b, off + 4 + len, len2, FALSE); |
| 120 | r = off + len + len2 + 4; |
| 121 | } |
| 122 | return (r); |
| 123 | } |
| 124 | |
| 125 | static void dissect_tripe(tvbuff_t *b, packet_info *p, proto_tree *t) |
| 126 | { |
| 127 | proto_item *ti; |
| 128 | proto_tree *tt; |
| 129 | guint8 ty; |
| 130 | gint off = tvb_raw_offset(b); |
| 131 | guint32 seq; |
| 132 | |
| 133 | /* --- Initialize the summary cells --- */ |
| 134 | |
| 135 | if (check_col(p->cinfo, COL_PROTOCOL)) |
| 136 | col_set_str(p->cinfo, COL_PROTOCOL, "TrIPE"); |
| 137 | ty = tvb_get_guint8(b, 0); |
| 138 | if (check_col(p->cinfo, COL_INFO)) { |
| 139 | col_clear(p->cinfo, COL_INFO); |
| 140 | switch (ty & MSG_CATMASK) { |
| 141 | case MSG_PACKET: |
| 142 | switch (ty & MSG_TYPEMASK) { |
| 143 | case 0: |
| 144 | col_set_str(p->cinfo, COL_INFO, "Packet data"); |
| 145 | break; |
| 146 | default: |
| 147 | col_add_fstr(p->cinfo, COL_INFO, |
| 148 | "Packet data, unknown type code %u", |
| 149 | ty & MSG_TYPEMASK); |
| 150 | break; |
| 151 | } |
| 152 | break; |
| 153 | case MSG_KEYEXCH: |
| 154 | switch (ty & MSG_TYPEMASK) { |
| 155 | case KX_PRECHAL: |
| 156 | col_set_str(p->cinfo, COL_INFO, "Key exchange, prechallenge"); |
| 157 | break; |
| 158 | case KX_COOKIE: |
| 159 | col_set_str(p->cinfo, COL_INFO, "Key exchange, cookie"); |
| 160 | break; |
| 161 | case KX_CHAL: |
| 162 | col_set_str(p->cinfo, COL_INFO, "Key exchange, challenge"); |
| 163 | break; |
| 164 | case KX_REPLY: |
| 165 | col_set_str(p->cinfo, COL_INFO, "Key exchange, reply"); |
| 166 | break; |
| 167 | case KX_SWITCH: |
| 168 | col_set_str(p->cinfo, COL_INFO, "Key exchange, switch request"); |
| 169 | break; |
| 170 | case KX_SWITCHOK: |
| 171 | col_set_str(p->cinfo, COL_INFO, "Key exchange, switch response"); |
| 172 | break; |
| 173 | default: |
| 174 | col_add_fstr(p->cinfo, COL_INFO, |
| 175 | "Key exchange, unknown type code %u", |
| 176 | ty & MSG_TYPEMASK); |
| 177 | break; |
| 178 | } |
| 179 | break; |
| 180 | default: |
| 181 | col_add_fstr(p->cinfo, COL_INFO, |
| 182 | "Unknown category code %u, unknown type code %u", |
| 183 | ty & MSG_CATMASK, ty & MSG_TYPEMASK); |
| 184 | break; |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | /* --- Fill in the tree --- */ |
| 189 | |
| 190 | if (t) { |
| 191 | ti = proto_tree_add_item(t, proto_tripe, b, 0, -1, FALSE); |
| 192 | tt = proto_item_add_subtree(ti, tt_tripe); |
| 193 | |
| 194 | proto_tree_add_item(tt, hf_tripe_cat, b, 0, 1, FALSE); |
| 195 | |
| 196 | off = 1; |
| 197 | switch (ty & MSG_CATMASK) { |
| 198 | case MSG_PACKET: |
| 199 | proto_tree_add_item(tt, hf_tripe_packet_type, b, 0, 1, FALSE); |
| 200 | switch (ty & MSG_TYPEMASK) { |
| 201 | case 0: |
| 202 | goto ct; |
| 203 | default: |
| 204 | goto huh; |
| 205 | } |
| 206 | break; |
| 207 | case MSG_KEYEXCH: |
| 208 | proto_tree_add_item(tt, hf_tripe_kx_type, b, 0, 1, FALSE); |
| 209 | switch (ty & MSG_TYPEMASK) { |
| 210 | case KX_PRECHAL: |
| 211 | off = getge(tt, &hf_tripe_kx_mychal, b, off); |
| 212 | goto tail; |
| 213 | case KX_COOKIE: |
| 214 | off = getge(tt, &hf_tripe_kx_mychal, b, off); |
| 215 | off = gethash(tt, hf_tripe_kx_yourcookie, b, off); |
| 216 | goto tail; |
| 217 | case KX_CHAL: |
| 218 | off = getge(tt, &hf_tripe_kx_mychal, b, off); |
| 219 | off = gethash(tt, hf_tripe_kx_yourcookie, b, off); |
| 220 | off = getmp(tt, &hf_tripe_kx_check, b, off); |
| 221 | goto tail; |
| 222 | case KX_REPLY: |
| 223 | off = gethash(tt, hf_tripe_kx_mycookie, b, off); |
| 224 | off = gethash(tt, hf_tripe_kx_yourcookie, b, off); |
| 225 | off = getmp(tt, &hf_tripe_kx_check, b, off); |
| 226 | goto ct; |
| 227 | case KX_SWITCH: |
| 228 | off = gethash(tt, hf_tripe_kx_mycookie, b, off); |
| 229 | off = gethash(tt, hf_tripe_kx_yourcookie, b, off); |
| 230 | goto ct; |
| 231 | case KX_SWITCHOK: |
| 232 | goto ct; |
| 233 | default: |
| 234 | goto huh; |
| 235 | } |
| 236 | break; |
| 237 | default: |
| 238 | goto huh; |
| 239 | } |
| 240 | tail: |
| 241 | if (tvb_offset_exists(b, off)) |
| 242 | goto huh; |
| 243 | goto done; |
| 244 | huh: |
| 245 | proto_tree_add_item(tt, hf_tripe_huh, b, off, -1, FALSE); |
| 246 | goto done; |
| 247 | ct: |
| 248 | ti = proto_tree_add_item(tt, hf_tripe_ct, b, off, -1, FALSE); |
| 249 | seq = tvb_get_ntohl(b, off + 10); |
| 250 | proto_item_set_text(ti, "Encrypted ciphertext (sequence number %lu)", |
| 251 | (unsigned long)seq); |
| 252 | tt = proto_item_add_subtree(ti, tt_tripe_ct); |
| 253 | proto_tree_add_item(tt, hf_tripe_ct_mac, b, off, 10, FALSE); |
| 254 | off += 10; |
| 255 | proto_tree_add_item(tt, hf_tripe_ct_seq, b, off, 4, FALSE); |
| 256 | off += 4; |
| 257 | proto_tree_add_item(tt, hf_tripe_ct_iv, b, off, 8, FALSE); |
| 258 | off += 8; |
| 259 | proto_tree_add_item(ti, hf_tripe_ct_cbc, b, off, -1, FALSE); |
| 260 | goto done; |
| 261 | done:; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | void proto_register_tripe(void) |
| 266 | { |
| 267 | static value_string vs_kxtype[] = { |
| 268 | { KX_PRECHAL, "KX_PRECHAL (prechallenge)" }, |
| 269 | { KX_COOKIE, "KX_COOKIE (cookie)" }, |
| 270 | { KX_CHAL, "KX_CHAL (challenge)" }, |
| 271 | { KX_REPLY, "KX_REPLY (reply)" }, |
| 272 | { KX_SWITCH, "KX_SWITCH (switch request)" }, |
| 273 | { KX_SWITCHOK, "KX_SWITCHOK (switch response)" }, |
| 274 | { 0, 0 } |
| 275 | }; |
| 276 | |
| 277 | static hf_register_info hfs[] = { |
| 278 | &hf_tripe_cat, { |
| 279 | "Message category", "tripe.cat", |
| 280 | FT_UINT8, BASE_HEX, 0, MSG_CATMASK |
| 281 | }, |
| 282 | &hf_tripe_packet_type, { |
| 283 | "Packet message type", "tripe.packet.type", |
| 284 | FT_UINT8, BASE_HEX, 0, MSG_TYPEMASK, |
| 285 | "This is the TrIPE packet type subcode." |
| 286 | }, |
| 287 | &hf_tripe_ct, { |
| 288 | "Encrypted ciphertext", "tripe.ct", |
| 289 | FT_BYTES, BASE_NONE, 0, 0, |
| 290 | "This is an encrypted message." |
| 291 | }, |
| 292 | &hf_tripe_ct_seq, { |
| 293 | "Ciphertext sequence number", "tripe.ct.seq", |
| 294 | FT_UINT32, BASE_DEC, 0, 0, |
| 295 | "This is the unique sequence number for the ciphertext." |
| 296 | }, |
| 297 | &hf_tripe_ct_iv, { |
| 298 | "Ciphertext initialization vector", "tripe.ct.iv", |
| 299 | FT_BYTES, BASE_NONE, 0, 0, |
| 300 | "This is the initialization vector used for the actual encryption." |
| 301 | }, |
| 302 | &hf_tripe_ct_cbc, { |
| 303 | "CBC-encrypted data", "tripe.ct.cbc", |
| 304 | FT_BYTES, BASE_NONE, 0, 0, |
| 305 | "This is the CBC-encrypted message. Reading it ought to be hard." |
| 306 | }, |
| 307 | &hf_tripe_ct_mac, { |
| 308 | "Message authentication code", "tripe.ct.mac", |
| 309 | FT_BYTES, BASE_NONE, 0, 0, |
| 310 | "This is the message authentication code for the ciphertext." |
| 311 | }, |
| 312 | &hf_tripe_kx_type, { |
| 313 | "Key-exchange message type", "tripe.kx.type", |
| 314 | FT_UINT8, BASE_HEX, vs_kxtype, MSG_TYPEMASK, |
| 315 | "This is the TrIPE key-exchange type subcode." |
| 316 | }, |
| 317 | &hf_tripe_kx_mychal.hf, { |
| 318 | "Sender's challenge data", "tripe.kx.mychal", |
| 319 | FT_BYTES, BASE_NONE, 0, 0, |
| 320 | "This is the sender's challenge." |
| 321 | }, |
| 322 | &hf_tripe_kx_mychal.hf_len, { |
| 323 | "Challenge length", "tripe.kx.mychal.len", |
| 324 | FT_UINT16, BASE_DEC, 0, 0, |
| 325 | "This is the length of the sender's challenge." |
| 326 | }, |
| 327 | &hf_tripe_kx_mychal.hf_val, { |
| 328 | "Challenge", "tripe.kx.mychal.val", |
| 329 | FT_BYTES, BASE_NONE, 0, 0, |
| 330 | "This is the value of the sender's challenge." |
| 331 | }, |
| 332 | &hf_tripe_kx_mychal.hfx_len, { |
| 333 | "Challenge x length", "tripe.kx.mychal.x.len", |
| 334 | FT_UINT16, BASE_DEC, 0, 0, |
| 335 | "This is the length of the sender's challenge x-coordinate." |
| 336 | }, |
| 337 | &hf_tripe_kx_mychal.hfy_val, { |
| 338 | "Challenge x value", "tripe.kx.mychal.x.val", |
| 339 | FT_BYTES, BASE_NONE, 0, 0, |
| 340 | "This is the value of the sender's challenge x-coordinate." |
| 341 | }, |
| 342 | &hf_tripe_kx_mychal.hfy_len, { |
| 343 | "Challenge y length", "tripe.kx.mychal.y.len", |
| 344 | FT_UINT16, BASE_DEC, 0, 0, |
| 345 | "This is the length of the sender's challenge x-coordinate." |
| 346 | }, |
| 347 | &hf_tripe_kx_mychal.hfx_val, { |
| 348 | "Challenge y value", "tripe.kx.mychal.y.val", |
| 349 | FT_BYTES, BASE_NONE, 0, 0, |
| 350 | "This is the value of the sender's challenge x-coordinate." |
| 351 | }, |
| 352 | &hf_tripe_kx_mycookie, { |
| 353 | "Sender's hashed cookie", "tripe.kx.mycookie", |
| 354 | FT_BYTES, BASE_NONE, 0, 0, |
| 355 | "This is the hash of the sender's challenge." |
| 356 | }, |
| 357 | &hf_tripe_kx_yourcookie, { |
| 358 | "Recipient's hashed cookie", "tripe.kx.yourcookie", |
| 359 | FT_BYTES, BASE_NONE, 0, 0, |
| 360 | "This is the hash of the recipient's challenge." |
| 361 | }, |
| 362 | &hf_tripe_kx_check.hf, { |
| 363 | "Challenge check-value", "tripe.kx.check", |
| 364 | FT_BYTES, BASE_NONE, 0, 0, |
| 365 | "This is an encrypted check-value which proves that the sender " |
| 366 | "knows the answer to the challenge, and that it is therefore honest." |
| 367 | }, |
| 368 | &hf_tripe_kx_check.hf_len, { |
| 369 | "Check-value length", "tripe.kx.check.len", |
| 370 | FT_UINT16, BASE_DEC, 0, 0, |
| 371 | "This is the length of the encrypted check-value." |
| 372 | }, |
| 373 | &hf_tripe_kx_check.hf_val, { |
| 374 | "Check-value data", "tripe.kx.check.val", |
| 375 | FT_BYTES, BASE_NONE, 0, 0, |
| 376 | "This is the actual encrypted check-value." |
| 377 | }, |
| 378 | &hf_tripe_huh, { |
| 379 | "Unknown data", "tripe.huh", |
| 380 | FT_BYTES, BASE_NONE, 0, 0, |
| 381 | "I don't know what's meant to appear here." |
| 382 | }, |
| 383 | }; |
| 384 | |
| 385 | static gint *tts[] = { |
| 386 | &tt_tripe, |
| 387 | &tt_tripe_ct, |
| 388 | &hf_tripe_kx_mychal.tt, |
| 389 | &hf_tripe_kx_check.tt, |
| 390 | }; |
| 391 | |
| 392 | proto_tripe = proto_register_protocol("TrIPE", "TrIPE", "tripe"); |
| 393 | proto_register_field_array(proto_tripe, hfs, array_length(hfs)); |
| 394 | proto_register_subtree_array(tts, array_length(tts)); |
| 395 | } |
| 396 | |
| 397 | void proto_reg_handoff_tripe(void) |
| 398 | { |
| 399 | dissector_handle_t dh; |
| 400 | |
| 401 | dh = create_dissector_handle(dissect_tripe, proto_tripe); |
| 402 | dissector_add("udp.port", 22003, dh); |
| 403 | } |
| 404 | |
| 405 | G_MODULE_EXPORT void plugin_reg_handoff(void) |
| 406 | { |
| 407 | proto_reg_handoff_tripe(); |
| 408 | } |
| 409 | |
| 410 | G_MODULE_EXPORT void plugin_init(plugin_address_table_t *pat) |
| 411 | { |
| 412 | plugin_address_table_init(pat); |
| 413 | if (proto_tripe == -1) |
| 414 | proto_register_tripe(); |
| 415 | } |
| 416 | |
| 417 | /*----- That's all, folks -------------------------------------------------*/ |