epan/dissectors/packet-kerberos4.c

   1 /* packet-kerberos4.c
   2  * Routines for Kerberos v4 packet dissection
   3  *
   4  * Ronnie Sahlberg 2004
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24 /*
  25  * PDU structure based on the document :
  26  *                                                              Section E.2.1
  27  *
  28  *                            Kerberos Authentication and Authorization System
  29  *
  30  *            by S. P. Miller, B. C. Neuman, J. I. Schiller, and J. H. Saltzer
  31  *
  32  */
  33
  34 #include "config.h"
  35
  36 #include <glib.h>
  37 #include <epan/packet.h>
  38
  39 void proto_register_krb4(void);
  40 void proto_reg_handoff_krb4(void);
  41
  42 static int proto_krb4 = -1;
  43 static int hf_krb4_version = -1;
  44 static int hf_krb4_auth_msg_type = -1;
  45 static int hf_krb4_m_type = -1;
  46 static int hf_krb4_byte_order = -1;
  47 static int hf_krb4_name = -1;
  48 static int hf_krb4_instance = -1;
  49 static int hf_krb4_realm = -1;
  50 static int hf_krb4_time_sec = -1;
  51 static int hf_krb4_exp_date = -1;
  52 static int hf_krb4_req_date = -1;
  53 static int hf_krb4_lifetime = -1;
  54 static int hf_krb4_s_name = -1;
  55 static int hf_krb4_s_instance = -1;
  56 static int hf_krb4_kvno = -1;
  57 static int hf_krb4_length = -1;
  58 static int hf_krb4_ticket_length = -1;
  59 static int hf_krb4_request_length = -1;
  60 static int hf_krb4_ticket_blob = -1;
  61 static int hf_krb4_request_blob = -1;
  62 static int hf_krb4_encrypted_blob = -1;
  63 static int hf_krb4_unknown_transarc_blob = -1;
  64
  65 static gint ett_krb4 = -1;
  66 static gint ett_krb4_auth_msg_type = -1;
  67
  68 #define UDP_PORT_KRB4    750
  69 #define TRANSARC_SPECIAL_VERSION 0x63
  70
  71 static const value_string byte_order_vals[] = {
  72         { 0,    "Big Endian" },
  73         { 1,    "Little Endian" },
  74         { 0,    NULL }
  75 };
  76
  77 #define AUTH_MSG_KDC_REQUEST            1
  78 #define AUTH_MSG_KDC_REPLY              2
  79 #define AUTH_MSG_APPL_REQUEST           3
  80 #define AUTH_MSG_APPL_REQUEST_MUTUAL    4
  81 #define AUTH_MSG_ERR_REPLY              5
  82 #define AUTH_MSG_PRIVATE                6
  83 #define AUTH_MSG_SAFE                   7
  84 #define AUTH_MSG_APPL_ERR               8
  85 #define AUTH_MSG_DIE                    63
  86 static const value_string m_type_vals[] = {
  87         { AUTH_MSG_KDC_REQUEST,         "KDC Request" },
  88         { AUTH_MSG_KDC_REPLY,           "KDC Reply" },
  89         { AUTH_MSG_APPL_REQUEST,        "Appl Request" },
  90         { AUTH_MSG_APPL_REQUEST_MUTUAL, "Appl Request Mutual" },
  91         { AUTH_MSG_ERR_REPLY,           "Err Reply" },
  92         { AUTH_MSG_PRIVATE,             "Private" },
  93         { AUTH_MSG_SAFE,                "Safe" },
  94         { AUTH_MSG_APPL_ERR,            "Appl Err" },
  95         { AUTH_MSG_DIE,                 "Die" },
  96         { 0,    NULL }
  97 };
  98
  99
 100 static int
 101 dissect_krb4_string(packet_info *pinfo _U_, int hf_index, proto_tree *tree, tvbuff_t *tvb, int offset)
 102 {
 103         proto_tree_add_item(tree, hf_index, tvb, offset, -1, ENC_ASCII|ENC_NA);
 104         while(tvb_get_guint8(tvb, offset)!=0){
 105                 offset++;
 106         }
 107         offset++;
 108
 109         return offset;
 110 }
 111
 112 static int
 113 dissect_krb4_kdc_request(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb, int offset, gboolean little_endian, int version)
 114 {
 115         nstime_t time_sec;
 116         guint8 lifetime;
 117
 118         if(version==TRANSARC_SPECIAL_VERSION){
 119                 proto_tree_add_item(tree, hf_krb4_unknown_transarc_blob, tvb, offset, 8, ENC_NA);
 120                 offset+=8;
 121         }
 122
 123         /* Name */
 124         offset=dissect_krb4_string(pinfo, hf_krb4_name, tree, tvb, offset);
 125
 126         /* Instance */
 127         offset=dissect_krb4_string(pinfo, hf_krb4_instance, tree, tvb, offset);
 128
 129         /* Realm */
 130         offset=dissect_krb4_string(pinfo, hf_krb4_realm, tree, tvb, offset);
 131
 132         /* Time sec */
 133         time_sec.secs=little_endian?tvb_get_letohl(tvb, offset):tvb_get_ntohl(tvb, offset);
 134         time_sec.nsecs=0;
 135         proto_tree_add_time(tree, hf_krb4_time_sec, tvb, offset, 4, &time_sec);
 136         offset+=4;
 137
 138         /* lifetime */
 139         lifetime=tvb_get_guint8(tvb, offset);
 140         proto_tree_add_uint_format_value(tree, hf_krb4_lifetime, tvb, offset, 1, lifetime, "%d (%d minutes)", lifetime, lifetime*5);
 141         offset++;
 142
 143         /* service Name */
 144         offset=dissect_krb4_string(pinfo, hf_krb4_s_name, tree, tvb, offset);
 145
 146         /* service Instance */
 147         offset=dissect_krb4_string(pinfo, hf_krb4_s_instance, tree, tvb, offset);
 148
 149         return offset;
 150 }
 151
 152
 153 static int
 154 dissect_krb4_kdc_reply(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb, int offset, gboolean little_endian)
 155 {
 156         nstime_t time_sec;
 157         guint32 length;
 158
 159         /* Name */
 160         offset=dissect_krb4_string(pinfo, hf_krb4_name, tree, tvb, offset);
 161
 162         /* Instance */
 163         offset=dissect_krb4_string(pinfo, hf_krb4_instance, tree, tvb, offset);
 164
 165         /* Realm */
 166         offset=dissect_krb4_string(pinfo, hf_krb4_realm, tree, tvb, offset);
 167
 168         /* Time sec */
 169         time_sec.secs=little_endian?tvb_get_letohl(tvb, offset):tvb_get_ntohl(tvb, offset);
 170         time_sec.nsecs=0;
 171         proto_tree_add_time(tree, hf_krb4_time_sec, tvb, offset, 4, &time_sec);
 172         offset+=4;
 173
 174         /*XXX unknown byte here */
 175         offset++;
 176
 177         /* exp date */
 178         time_sec.secs=little_endian?tvb_get_letohl(tvb, offset):tvb_get_ntohl(tvb, offset);
 179         time_sec.nsecs=0;
 180         proto_tree_add_time(tree, hf_krb4_exp_date, tvb, offset, 4, &time_sec);
 181         offset+=4;
 182
 183         /* kvno */
 184         proto_tree_add_item(tree, hf_krb4_kvno, tvb, offset, 1, ENC_BIG_ENDIAN);
 185         offset++;
 186
 187         /* length2 */
 188         length=little_endian?tvb_get_letohs(tvb, offset):tvb_get_ntohs(tvb, offset);
 189         proto_tree_add_uint_format_value(tree, hf_krb4_length, tvb, offset, 2, length, "%d", length);
 190         offset+=2;
 191
 192         /* encrypted blob */
 193         proto_tree_add_item(tree, hf_krb4_encrypted_blob, tvb, offset, length, ENC_NA);
 194         offset+=length;
 195
 196         return offset;
 197 }
 198
 199
 200 static int
 201 dissect_krb4_appl_request(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb, int offset, gboolean little_endian)
 202 {
 203         guint8 tlen, rlen;
 204         nstime_t time_sec;
 205         guint8 lifetime;
 206
 207         /* kvno */
 208         proto_tree_add_item(tree, hf_krb4_kvno, tvb, offset, 1, ENC_BIG_ENDIAN);
 209         offset++;
 210
 211         /* Realm */
 212         offset=dissect_krb4_string(pinfo, hf_krb4_realm, tree, tvb, offset);
 213
 214         /* ticket length */
 215         tlen=tvb_get_guint8(tvb, offset);
 216         proto_tree_add_item(tree, hf_krb4_ticket_length, tvb, offset, 1, ENC_BIG_ENDIAN);
 217         offset++;
 218
 219         /* request length */
 220         rlen=tvb_get_guint8(tvb, offset);
 221         proto_tree_add_item(tree, hf_krb4_request_length, tvb, offset, 1, ENC_BIG_ENDIAN);
 222         offset++;
 223
 224         /* ticket */
 225         proto_tree_add_item(tree, hf_krb4_ticket_blob, tvb, offset, tlen, ENC_NA);
 226         offset+=tlen;
 227
 228         /* request */
 229         proto_tree_add_item(tree, hf_krb4_request_blob, tvb, offset, rlen, ENC_NA);
 230         offset+=rlen;
 231
 232         /* request time */
 233         time_sec.secs=little_endian?tvb_get_letohl(tvb, offset):tvb_get_ntohl(tvb, offset);
 234         time_sec.nsecs=0;
 235         proto_tree_add_time(tree, hf_krb4_req_date, tvb, offset, 4, &time_sec);
 236         offset+=4;
 237
 238         /* lifetime */
 239         lifetime=tvb_get_guint8(tvb, offset);
 240         proto_tree_add_uint_format_value(tree, hf_krb4_lifetime, tvb, offset, 1, lifetime, "%d (%d minutes)", lifetime, lifetime*5);
 241         offset++;
 242
 243         /* service Name */
 244         offset=dissect_krb4_string(pinfo, hf_krb4_s_name, tree, tvb, offset);
 245
 246         /* service Instance */
 247         offset=dissect_krb4_string(pinfo, hf_krb4_s_instance, tree, tvb, offset);
 248
 249         return offset;
 250 }
 251
 252
 253
 254 static int
 255 dissect_krb4_auth_msg_type(packet_info *pinfo, proto_tree *parent_tree, tvbuff_t *tvb, int offset, int version)
 256 {
 257         proto_tree *tree;
 258         proto_item *item;
 259         guint8 auth_msg_type;
 260
 261         auth_msg_type=tvb_get_guint8(tvb, offset);
 262         item = proto_tree_add_item(parent_tree, hf_krb4_auth_msg_type, tvb, offset, 1, ENC_BIG_ENDIAN);
 263         tree = proto_item_add_subtree(item, ett_krb4_auth_msg_type);
 264
 265         /* m_type */
 266         proto_tree_add_item(tree, hf_krb4_m_type, tvb, offset, 1, ENC_BIG_ENDIAN);
 267         col_append_fstr(pinfo->cinfo, COL_INFO, "%s%s",
 268            (version==TRANSARC_SPECIAL_VERSION)?"TRANSARC-":"",
 269             val_to_str(auth_msg_type>>1, m_type_vals, "Unknown (0x%04x)"));
 270         proto_item_append_text(item, " %s%s",
 271            (version==TRANSARC_SPECIAL_VERSION)?"TRANSARC-":"",
 272            val_to_str(auth_msg_type>>1, m_type_vals, "Unknown (0x%04x)"));
 273
 274         /* byte order */
 275         proto_tree_add_item(tree, hf_krb4_byte_order, tvb, offset, 1, ENC_BIG_ENDIAN);
 276         proto_item_append_text(item, " (%s)", val_to_str(auth_msg_type&0x01, byte_order_vals, "Unknown (0x%04x)"));
 277
 278         offset++;
 279         return offset;
 280 }
 281
 282 static gboolean
 283 dissect_krb4(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
 284 {
 285         proto_tree *tree;
 286         proto_item *item;
 287         guint8 version, opcode;
 288         int offset=0;
 289
 290         /* this should better have the value 4 or it might be a weirdo
 291          * Transarc AFS special unknown thing.
 292          */
 293         version=tvb_get_guint8(tvb, offset);
 294         if((version!=4)&&(version!=TRANSARC_SPECIAL_VERSION)){
 295                 return FALSE;
 296         }
 297
 298         opcode=tvb_get_guint8(tvb, offset+1);
 299         switch(opcode>>1){
 300         case AUTH_MSG_KDC_REQUEST:
 301         case AUTH_MSG_KDC_REPLY:
 302         case AUTH_MSG_APPL_REQUEST:
 303         case AUTH_MSG_APPL_REQUEST_MUTUAL:
 304         case AUTH_MSG_ERR_REPLY:
 305         case AUTH_MSG_PRIVATE:
 306         case AUTH_MSG_SAFE:
 307         case AUTH_MSG_APPL_ERR:
 308         case AUTH_MSG_DIE:
 309                 break;
 310         default:
 311                 return FALSE;
 312         }
 313
 314         /* create a tree for krb4 */
 315         item = proto_tree_add_item(parent_tree, proto_krb4, tvb, offset, -1, ENC_NA);
 316         tree = proto_item_add_subtree(item, ett_krb4);
 317
 318         col_set_str(pinfo->cinfo, COL_PROTOCOL, "KRB4");
 319         col_clear(pinfo->cinfo, COL_INFO);
 320
 321         /* version */
 322         proto_tree_add_item(tree, hf_krb4_version, tvb, offset, 1, ENC_BIG_ENDIAN);
 323         offset++;
 324
 325         /* auth_msg_type */
 326         offset = dissect_krb4_auth_msg_type(pinfo, tree, tvb, offset, version);
 327
 328         switch(opcode>>1){
 329         case AUTH_MSG_KDC_REQUEST:
 330                 /*offset =*/ dissect_krb4_kdc_request(pinfo, tree, tvb, offset, opcode&0x01, version);
 331                 break;
 332         case AUTH_MSG_KDC_REPLY:
 333                 /*offset =*/ dissect_krb4_kdc_reply(pinfo, tree, tvb, offset, opcode&0x01);
 334                 break;
 335         case AUTH_MSG_APPL_REQUEST:
 336                 /*offset =*/ dissect_krb4_appl_request(pinfo, tree, tvb, offset, opcode&0x01);
 337                 break;
 338         case AUTH_MSG_APPL_REQUEST_MUTUAL:
 339         case AUTH_MSG_ERR_REPLY:
 340         case AUTH_MSG_PRIVATE:
 341         case AUTH_MSG_SAFE:
 342         case AUTH_MSG_APPL_ERR:
 343         case AUTH_MSG_DIE:
 344                 break;
 345         }
 346         return TRUE;
 347 }
 348
 349 void
 350 proto_register_krb4(void)
 351 {
 352   static hf_register_info hf[] = {
 353     { &hf_krb4_version,
 354       { "Version", "krb4.version",
 355         FT_UINT8, BASE_DEC, NULL, 0x0,
 356         "Kerberos(v4) version number", HFILL }},
 357     { &hf_krb4_auth_msg_type,
 358       { "Msg Type", "krb4.auth_msg_type",
 359         FT_UINT8, BASE_HEX, NULL, 0x0,
 360         "Message Type/Byte Order", HFILL }},
 361     { &hf_krb4_m_type,
 362       { "M Type", "krb4.m_type",
 363         FT_UINT8, BASE_HEX, VALS(m_type_vals), 0xfe,
 364         "Message Type", HFILL }},
 365     { &hf_krb4_byte_order,
 366       { "Byte Order", "krb4.byte_order",
 367         FT_UINT8, BASE_HEX, VALS(byte_order_vals), 0x01,
 368         NULL, HFILL }},
 369     { &hf_krb4_name,
 370       { "Name", "krb4.name",
 371         FT_STRINGZ, BASE_NONE, NULL, 0x00,
 372         NULL, HFILL }},
 373     { &hf_krb4_instance,
 374       { "Instance", "krb4.instance",
 375         FT_STRINGZ, BASE_NONE, NULL, 0x00,
 376         NULL, HFILL }},
 377     { &hf_krb4_realm,
 378       { "Realm", "krb4.realm",
 379         FT_STRINGZ, BASE_NONE, NULL, 0x00,
 380         NULL, HFILL }},
 381     { &hf_krb4_time_sec,
 382       { "Time Sec", "krb4.time_sec",
 383         FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x00,
 384         NULL, HFILL }},
 385     { &hf_krb4_exp_date,
 386       { "Exp Date", "krb4.exp_date",
 387         FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x00,
 388         NULL, HFILL }},
 389     { &hf_krb4_req_date,
 390       { "Req Date", "krb4.req_date",
 391         FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x00,
 392         NULL, HFILL }},
 393     { &hf_krb4_lifetime,
 394       { "Lifetime", "krb4.lifetime",
 395         FT_UINT8, BASE_DEC, NULL, 0x00,
 396         "Lifetime (in 5 min units)", HFILL }},
 397     { &hf_krb4_s_name,
 398       { "Service Name", "krb4.s_name",
 399         FT_STRINGZ, BASE_NONE, NULL, 0x00,
 400         NULL, HFILL }},
 401     { &hf_krb4_s_instance,
 402       { "Service Instance", "krb4.s_instance",
 403         FT_STRINGZ, BASE_NONE, NULL, 0x00,
 404         NULL, HFILL }},
 405     { &hf_krb4_kvno,
 406       { "Kvno", "krb4.kvno",
 407         FT_UINT8, BASE_DEC, NULL, 0x00,
 408         "Key Version No", HFILL }},
 409     { &hf_krb4_length,
 410       { "Length", "krb4.length",
 411         FT_UINT32, BASE_DEC, NULL, 0x00,
 412         "Length of encrypted blob", HFILL }},
 413     { &hf_krb4_ticket_length,
 414       { "Ticket Length", "krb4.ticket.length",
 415         FT_UINT8, BASE_DEC, NULL, 0x00,
 416         "Length of ticket", HFILL }},
 417     { &hf_krb4_request_length,
 418       { "Request Length", "krb4.request.length",
 419         FT_UINT8, BASE_DEC, NULL, 0x00,
 420         "Length of request", HFILL }},
 421     { &hf_krb4_ticket_blob,
 422       { "Ticket Blob", "krb4.ticket.blob",
 423         FT_BYTES, BASE_NONE, NULL, 0x00,
 424         NULL, HFILL }},
 425     { &hf_krb4_request_blob,
 426       { "Request Blob", "krb4.request.blob",
 427         FT_BYTES, BASE_NONE, NULL, 0x00,
 428         NULL, HFILL }},
 429     { &hf_krb4_encrypted_blob,
 430       { "Encrypted Blob", "krb4.encrypted_blob",
 431         FT_BYTES, BASE_NONE, NULL, 0x00,
 432         NULL, HFILL }},
 433     { &hf_krb4_unknown_transarc_blob,
 434       { "Unknown Transarc Blob", "krb4.unknown_transarc_blob",
 435         FT_BYTES, BASE_NONE, NULL, 0x00,
 436         "Unknown blob only present in Transarc packets", HFILL }},
 437   };
 438   static gint *ett[] = {
 439     &ett_krb4,
 440     &ett_krb4_auth_msg_type,
 441   };
 442
 443   proto_krb4 = proto_register_protocol("Kerberos v4",
 444                                        "KRB4", "krb4");
 445   new_register_dissector("krb4", dissect_krb4, proto_krb4);
 446   proto_register_field_array(proto_krb4, hf, array_length(hf));
 447   proto_register_subtree_array(ett, array_length(ett));
 448 }
 449
 450 void
 451 proto_reg_handoff_krb4(void)
 452 {
 453   dissector_handle_t krb4_handle;
 454
 455   krb4_handle = find_dissector("krb4");
 456   dissector_add_uint("udp.port", UDP_PORT_KRB4, krb4_handle);
 457 }