packet-ssh.c

   1 /* packet-ssh.c
   2  * Routines for ssh packet dissection
   3  *
   4  * Huagang XIE <huagang@intruvert.com>
   5  *
   6  * $Id: packet-ssh.c,v 1.7 2003/04/17 07:39:18 guy Exp $
   7  *
   8  * Ethereal - Network traffic analyzer
   9  * By Gerald Combs <gerald@ethereal.com>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * Copied from packet-mysql.c
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program 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 this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  27  *
  28  *
  29  * Note:  support SSH v1 and v2  now.
  30  *
  31  */
  32
  33 #ifdef HAVE_CONFIG_H
  34 # include "config.h"
  35 #endif
  36
  37 #include <glib.h>
  38 #include <epan/packet.h>
  39 #include <epan/conversation.h>
  40
  41 #include "packet-smb-common.h"
  42 #include "packet-tcp.h"
  43 #include "reassemble.h"
  44 #include "prefs.h"
  45
  46 /* get from openssh ssh2.h */
  47 #define SSH2_MSG_DISCONNECT                             1
  48 #define SSH2_MSG_IGNORE                                 2
  49 #define SSH2_MSG_UNIMPLEMENTED                          3
  50 #define SSH2_MSG_DEBUG                                  4
  51 #define SSH2_MSG_SERVICE_REQUEST                        5
  52 #define SSH2_MSG_SERVICE_ACCEPT                         6
  53
  54 /* transport layer: alg negotiation */
  55
  56 #define SSH2_MSG_KEXINIT                                20
  57 #define SSH2_MSG_NEWKEYS                                21
  58
  59 /* transport layer: kex specific messages, can be reused */
  60
  61 #define SSH2_MSG_KEXDH_INIT                             30
  62 #define SSH2_MSG_KEXDH_REPLY                            31
  63
  64 /*
  65 #define SSH2_MSG_KEX_DH_GEX_REQUEST_OLD                 30
  66 #define SSH2_MSG_KEX_DH_GEX_GROUP                       31
  67 */
  68 #define SSH2_MSG_KEX_DH_GEX_INIT                        32
  69 #define SSH2_MSG_KEX_DH_GEX_REPLY                       33
  70 #define SSH2_MSG_KEX_DH_GEX_REQUEST                     34
  71
  72 /* SSH Version 1 definition , from openssh ssh1.h */
  73
  74 #define SSH_MSG_NONE                            0       /* no message */
  75 #define SSH_MSG_DISCONNECT                      1       /* cause (string) */
  76 #define SSH_SMSG_PUBLIC_KEY                     2       /* ck,msk,srvk,hostk */
  77 #define SSH_CMSG_SESSION_KEY                    3       /* key (BIGNUM) */
  78 #define SSH_CMSG_USER                           4       /* user (string) */
  79
  80
  81 #define SSH_VERSION_UNKNOWN     0
  82 #define SSH_VERSION_1           1
  83 #define SSH_VERSION_2           2
  84
  85 /* proto data */
  86
  87 struct ssh_pdu_data{
  88         guint   counter;
  89         guint   number;
  90 };
  91
  92 struct ssh_flow_data {
  93         guint   req_counter;
  94         guint   rsp_counter;
  95         guint   version;
  96 };
  97 static GMemChunk *ssh_this_data=NULL;
  98 static GMemChunk *ssh_global_data = NULL;
  99
 100 static int proto_ssh = -1;
 101 static int hf_ssh_packet_length= -1;
 102 static int hf_ssh_padding_length= -1;
 103 static int hf_ssh_payload= -1;
 104 static int hf_ssh_protocol= -1;
 105 static int hf_ssh_encrypted_packet= -1;
 106 static int hf_ssh_padding_string= -1;
 107 static int hf_ssh_mac_string= -1;
 108 static int hf_ssh_msg_code = -1;
 109 static int hf_ssh_cookie = -1;
 110 static int hf_ssh_kex_algorithms = -1;
 111 static int hf_ssh_server_host_key_algorithms = -1;
 112 static int hf_ssh_encryption_algorithms_client_to_server = -1;
 113 static int hf_ssh_encryption_algorithms_server_to_client = -1;
 114 static int hf_ssh_mac_algorithms_client_to_server=-1;
 115 static int hf_ssh_mac_algorithms_server_to_client=-1;
 116 static int hf_ssh_compression_algorithms_client_to_server=-1;
 117 static int hf_ssh_compression_algorithms_server_to_client=-1;
 118 static int hf_ssh_languages_client_to_server=-1;
 119 static int hf_ssh_languages_server_to_client=-1;
 120 static int hf_ssh_kex_algorithms_length= -1;
 121 static int hf_ssh_server_host_key_algorithms_length= -1;
 122 static int hf_ssh_encryption_algorithms_client_to_server_length= -1;
 123 static int hf_ssh_encryption_algorithms_server_to_client_length= -1;
 124 static int hf_ssh_mac_algorithms_client_to_server_length= -1;
 125 static int hf_ssh_mac_algorithms_server_to_client_length= -1;
 126 static int hf_ssh_compression_algorithms_client_to_server_length= -1;
 127 static int hf_ssh_compression_algorithms_server_to_client_length= -1;
 128 static int hf_ssh_languages_client_to_server_length= -1;
 129 static int hf_ssh_languages_server_to_client_length= -1;
 130
 131 static gint ett_ssh = -1;
 132 static gint ett_key_exchange= -1;
 133 static gint ett_key_init= -1;
 134 static gint ett_ssh1= -1;
 135 static gint ett_ssh2= -1;
 136
 137 static gboolean ssh_desegment = TRUE;
 138
 139 #define TCP_PORT_SSH  22
 140
 141 static const value_string ssh2_msg_vals[] = {
 142         {SSH2_MSG_DISCONNECT, "Disconnect"},
 143         {SSH2_MSG_IGNORE, "Ignore"},
 144         {SSH2_MSG_UNIMPLEMENTED, "Unimplemented"},
 145         {SSH2_MSG_DEBUG, "Debug"},
 146         {SSH2_MSG_SERVICE_REQUEST, "Service Request"},
 147         {SSH2_MSG_SERVICE_ACCEPT, "Service Accept"},
 148         {SSH2_MSG_KEXINIT, "Key Exchange Init"},
 149         {SSH2_MSG_NEWKEYS, "New Keys"},
 150         {SSH2_MSG_KEXDH_INIT, "Diffie-Hellman Key Exchange Init"},
 151         {SSH2_MSG_KEXDH_REPLY, "Diffie-Hellman Key Exchange Reply"},
 152         {SSH2_MSG_KEX_DH_GEX_INIT, "Diffie-Hellman GEX Init"},
 153         {SSH2_MSG_KEX_DH_GEX_REPLY, "Diffie-Hellman GEX Reply"},
 154         {SSH2_MSG_KEX_DH_GEX_REQUEST, "Diffie-Hellman GEX Request"},
 155         { 0,          NULL }
 156 };
 157
 158 static const value_string ssh1_msg_vals[] = {
 159         {SSH_MSG_NONE,"No Message"},
 160         {SSH_MSG_DISCONNECT, "Disconnect"},
 161         {SSH_SMSG_PUBLIC_KEY,"Public Key"},
 162         {SSH_CMSG_SESSION_KEY,"Session Key"},
 163         {SSH_CMSG_USER,"User"},
 164 };
 165
 166
 167 static const value_string ssh_opcode_vals[] = {
 168   { 0,          NULL }
 169 };
 170
 171 static int ssh_dissect_key_init(tvbuff_t *tvb, int offset, proto_tree *tree);
 172
 173 static int ssh_dissect_ssh1(tvbuff_t *tvb, packet_info *pinfo,
 174                 int offset, proto_tree *tree,int is_response,
 175                 int number, gboolean *need_desegmentation);
 176 static int ssh_dissect_ssh2(tvbuff_t *tvb, packet_info *pinfo,
 177                 int offset, proto_tree *tree,int is_response,
 178                 int number, gboolean *need_desegmentation );
 179 static int ssh_dissect_key_exchange(tvbuff_t *tvb, packet_info *pinfo,
 180                 int offset, proto_tree *tree,int is_response,
 181                 int number, gboolean *need_desegmentation );
 182 static int ssh_dissect_protocol(tvbuff_t *tvb, packet_info *pinfo,
 183                 int offset, proto_tree *tree,int is_response,int *version,
 184                 gboolean *need_desegmentation);
 185 static int ssh_dissect_encrypted_packet(tvbuff_t *tvb, packet_info *pinfo,
 186                 int offset, proto_tree *tree,int is_response);
 187 proto_item * ssh_proto_tree_add_item(proto_tree *tree, int hfindex, tvbuff_t *tvb,
 188     gint start, gint length, gboolean little_endian);
 189
 190 static void
 191 ssh_init_protocol(void)
 192 {
 193         if (ssh_global_data)
 194                 g_mem_chunk_destroy(ssh_global_data);
 195         if (ssh_this_data)
 196                 g_mem_chunk_destroy(ssh_this_data);
 197
 198         ssh_global_data = g_mem_chunk_new("ssh_global_datas",
 199                                       sizeof(struct ssh_flow_data),
 200                                       100* sizeof(struct ssh_flow_data), G_ALLOC_AND_FREE);
 201         ssh_this_data = g_mem_chunk_new("ssh_pku_data",
 202                                       sizeof(struct ssh_pdu_data),
 203                                       100* sizeof(struct ssh_pdu_data), G_ALLOC_AND_FREE);
 204
 205 }
 206
 207 static void
 208 dissect_ssh(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 209 {
 210
 211         proto_tree      *ssh_tree = NULL;
 212         proto_item      *ti;
 213         conversation_t  *conversation=NULL;
 214         gint            remain_length;
 215         int             last_offset;
 216         guint           this_number,number;
 217
 218         int             offset = 0;
 219
 220         gboolean        is_response;
 221         gboolean        is_newdata;
 222         gboolean        need_desegmentation;
 223         guint           version;
 224
 225         struct ssh_pdu_data *this_data=NULL;
 226         struct ssh_flow_data *global_data=NULL;
 227
 228         is_newdata = FALSE;
 229         this_data = p_get_proto_data(pinfo->fd, proto_ssh);
 230
 231         conversation = find_conversation(&pinfo->src, &pinfo->dst, pinfo->ptype,
 232                 pinfo->srcport, pinfo->destport, 0);
 233
 234         if (!conversation) {
 235                 /* create a new conversation */
 236                 conversation = conversation_new(&pinfo->src, &pinfo->dst, pinfo->ptype,
 237                         pinfo->srcport, pinfo->destport, 0);
 238         }
 239
 240         global_data = conversation_get_proto_data(conversation,proto_ssh);
 241         if(!global_data ) {
 242                 global_data = g_mem_chunk_alloc(ssh_global_data);
 243                 global_data->req_counter=0;
 244                 global_data->rsp_counter=0;
 245                 global_data->version=SSH_VERSION_UNKNOWN;
 246                 conversation_add_proto_data(conversation,proto_ssh,global_data);
 247         }
 248
 249 /*
 250  *      end of attaching data
 251  */
 252         if (pinfo->destport == pinfo->match_port) {
 253                 is_response=FALSE;
 254                 if(!this_data) {
 255                         this_data = g_mem_chunk_alloc(ssh_this_data);
 256                         this_data->counter = global_data->req_counter++;
 257                         p_add_proto_data(pinfo->fd, proto_ssh, this_data);
 258                         is_newdata = TRUE;
 259                 }
 260         }else {
 261                 is_response=TRUE;
 262                 if(!this_data) {
 263                         this_data = g_mem_chunk_alloc(ssh_global_data);
 264                         this_data->counter = global_data->rsp_counter++;
 265                         p_add_proto_data(pinfo->fd, proto_ssh, this_data);
 266                         is_newdata = TRUE;
 267                 }
 268         }
 269         if(tree) {
 270                   ti = proto_tree_add_item(tree, proto_ssh, tvb, offset, -1, FALSE);
 271                   ssh_tree = proto_item_add_subtree(ti, ett_ssh);
 272         }
 273         number = 0;
 274
 275         version = global_data->version;
 276
 277         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 278                 switch(version) {
 279                         case SSH_VERSION_UNKNOWN:
 280                                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SSH");
 281                                 break;
 282                         case SSH_VERSION_1:
 283                                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SSHv1");
 284                                 break;
 285                         case SSH_VERSION_2:
 286                                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SSHv2");
 287                                 break;
 288
 289                 }
 290         }
 291
 292         if(this_data->counter != 0 && version == SSH_VERSION_UNKNOWN) {
 293                 offset = ssh_dissect_encrypted_packet(tvb, pinfo,
 294                         offset,ssh_tree,is_response);
 295                 return;
 296         }
 297
 298         while((remain_length = tvb_reported_length_remaining(tvb,offset))> 0 ) {
 299                 need_desegmentation = FALSE;
 300                 last_offset = offset;
 301                 this_number = this_data->counter+number;
 302
 303                 if(number > 1 && is_newdata) {
 304                         /* update the this_data and flow_data */
 305                         if(is_response) {
 306                                 global_data->rsp_counter++;
 307                         } else {
 308                                 global_data->req_counter++;
 309                         }
 310                 }
 311
 312                 number++;
 313                 if(this_number == 0)  {
 314                         offset = ssh_dissect_protocol(tvb, pinfo,
 315                                         offset,ssh_tree, is_response,
 316                                         &version, &need_desegmentation);
 317                         if(!is_response) {
 318                                 global_data->version= version;
 319                         }
 320                 } else {
 321                         if(version == SSH_VERSION_1) {
 322                                 offset = ssh_dissect_ssh1(tvb, pinfo,
 323                                                 offset,ssh_tree,is_response,this_number,
 324                                                 &need_desegmentation);
 325                         } else if(version == SSH_VERSION_2) {
 326                                 offset = ssh_dissect_ssh2(tvb, pinfo,
 327                                                 offset,ssh_tree,is_response,this_number,
 328                                                 &need_desegmentation);
 329                         }
 330                 }
 331
 332                 if(need_desegmentation) return;
 333         }
 334 }
 335
 336 static int
 337 ssh_dissect_ssh2(tvbuff_t *tvb, packet_info *pinfo,
 338                 int offset, proto_tree *tree,int is_response, int this_number,
 339                 gboolean *need_desegmentation)
 340 {
 341         proto_item *ti;
 342         proto_item *ssh2_tree=NULL;
 343
 344         if(tree) {
 345                 ti=proto_tree_add_text(tree,tvb,offset,-1,"SSH Version 2");
 346                 ssh2_tree = proto_item_add_subtree(ti ,ett_ssh2);
 347         }
 348
 349         if((is_response && this_number > 3) || (!is_response && this_number>4)) {
 350                 offset = ssh_dissect_encrypted_packet(tvb, pinfo,
 351                                 offset,ssh2_tree,is_response);
 352         } else {
 353                 offset = ssh_dissect_key_exchange(tvb,pinfo,
 354                         offset,ssh2_tree,is_response,this_number,
 355                         need_desegmentation);
 356         }
 357
 358         return offset;
 359 }
 360 static int
 361 ssh_dissect_ssh1(tvbuff_t *tvb, packet_info *pinfo,
 362                 int offset, proto_tree *tree,int is_response,
 363                 int number, gboolean *need_desegmentation)
 364 {
 365         guint   plen, padding_length,len;
 366         guint8  msg_code;
 367         guint   remain_length;
 368
 369         proto_item *ti;
 370         proto_item *ssh1_tree =NULL;
 371
 372         if(tree) {
 373                 ti=proto_tree_add_text(tree,tvb,offset,-1,"SSH Version 1");
 374                 ssh1_tree = proto_item_add_subtree(ti ,ett_ssh1);
 375         }
 376
 377         /*
 378          * We use "tvb_ensure_length_remaining()" to make sure there
 379          * actually *is* data remaining.
 380          *
 381          * This means we're guaranteed that "remain_length" is positive.
 382          */
 383         remain_length = tvb_ensure_length_remaining(tvb,offset);
 384         if (ssh_desegment && pinfo->can_desegment) {
 385                 if(remain_length < 4) {
 386                         pinfo->desegment_offset = offset;
 387                         pinfo->desegment_len = 4-remain_length;
 388                         *need_desegmentation = TRUE;
 389                         return offset;
 390                 }
 391         }
 392         plen = tvb_get_ntohl(tvb, offset) ;
 393         padding_length  = 8 - plen%8;
 394
 395
 396         if (ssh_desegment && pinfo->can_desegment) {
 397                 if(plen+4+padding_length >  remain_length ) {
 398                         pinfo->desegment_offset = offset;
 399                         pinfo->desegment_len = plen+padding_length - remain_length;
 400                         *need_desegmentation = TRUE;
 401                         return offset;
 402                 }
 403         }
 404
 405         if (check_col(pinfo->cinfo, COL_INFO)) {
 406                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s: ",
 407                         is_response?"Server":"Client");
 408         }
 409
 410         if(plen >= 0xffff) {
 411                 if (ssh1_tree && plen > 0) {
 412                           proto_tree_add_uint_format(ssh1_tree, hf_ssh_packet_length, tvb,
 413                             offset, 4, plen,"Overly large length %x",plen);
 414                 }
 415                 plen = remain_length-4-padding_length;
 416         } else {
 417                 if (ssh1_tree && plen > 0) {
 418                           proto_tree_add_uint(ssh1_tree, hf_ssh_packet_length, tvb,
 419                             offset, 4, plen);
 420                 }
 421         }
 422         offset+=4;
 423 /* padding length */
 424
 425         if (tree) {
 426                   proto_tree_add_uint(ssh1_tree, hf_ssh_padding_length, tvb,
 427                     offset, padding_length, padding_length);
 428         }
 429         offset += padding_length;
 430 /*
 431         if(tree) {
 432                 tf=proto_tree_add_text(tree,tvb,offset,-1,"SSH Version 1");
 433                 ssh1_tree = proto_item_add_subtree(tf ,ett_ssh1);
 434         }
 435 */
 436         /* msg_code */
 437         if(number == 1 ) {
 438                 msg_code = tvb_get_guint8(tvb, offset);
 439                 if (tree) {
 440                         proto_tree_add_uint_format(ssh1_tree, hf_ssh_msg_code, tvb,
 441                                 offset, 1, msg_code,"Msg code: %s (%u)",
 442                                 val_to_str(msg_code, ssh1_msg_vals, "Unknown (%u)"),
 443                                 msg_code);
 444                 }
 445                 if (check_col(pinfo->cinfo, COL_INFO)) {
 446                         col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
 447                         val_to_str(msg_code, ssh1_msg_vals, "Unknown (%u)"));
 448                 }
 449                 offset += 1;
 450                 len = plen -1;
 451         } else {
 452                 len = plen;
 453                 if (check_col(pinfo->cinfo, COL_INFO)) {
 454                         col_append_fstr(pinfo->cinfo, COL_INFO, "Encrypted packet len=%d", len);
 455                 }
 456         }
 457         /* payload */
 458         if (ssh1_tree ) {
 459                 ssh_proto_tree_add_item(ssh1_tree, hf_ssh_payload,
 460                     tvb, offset, len, FALSE);
 461         }
 462         offset+=len;
 463
 464         return offset;
 465 }
 466
 467 static int
 468 ssh_dissect_key_exchange(tvbuff_t *tvb, packet_info *pinfo,
 469                 int offset, proto_tree *tree,int is_response,int number,
 470                 gboolean *need_desegmentation)
 471 {
 472         guint   plen,len;
 473         guint8  padding_length;
 474         guint   remain_length;
 475         int     last_offset=offset;
 476         guint   msg_code;
 477
 478         proto_item *tf;
 479         proto_item *key_ex_tree =NULL;
 480
 481         /*
 482          * We use "tvb_ensure_length_remaining()" to make sure there
 483          * actually *is* data remaining.
 484          *
 485          * This means we're guaranteed that "remain_length" is positive.
 486          */
 487         remain_length = tvb_ensure_length_remaining(tvb,offset);
 488         if (ssh_desegment && pinfo->can_desegment) {
 489                 if(remain_length < 4) {
 490                         pinfo->desegment_offset = offset;
 491                         pinfo->desegment_len = 4-remain_length;
 492                         *need_desegmentation = TRUE;
 493                         return offset;
 494                 }
 495         }
 496         plen = tvb_get_ntohl(tvb, offset) ;
 497
 498         if (ssh_desegment && pinfo->can_desegment) {
 499                 if(plen +4 >  remain_length ) {
 500                         pinfo->desegment_offset = offset;
 501                         pinfo->desegment_len = plen+4 - remain_length;
 502                         *need_desegmentation = TRUE;
 503                         return offset;
 504                 }
 505         }
 506         /*
 507          * Need to check plen > 0x80000000 here
 508          */
 509
 510         if (check_col(pinfo->cinfo, COL_INFO)) {
 511                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s: ",
 512                         is_response?"Server":"Client");
 513         }
 514
 515         if(plen >= 0xffff) {
 516                 if (tree) {
 517                         proto_tree_add_uint_format(tree, hf_ssh_packet_length, tvb,
 518                                 offset, 4, plen,"Overly large number 0x%x",plen);
 519                 }
 520                 plen = remain_length-4;
 521         } else {
 522                 if (tree) {
 523                         proto_tree_add_uint(tree, hf_ssh_packet_length, tvb,
 524                                 offset, 4, plen);
 525                 }
 526         }
 527         offset+=4;
 528 /* padding length */
 529         padding_length = tvb_get_guint8(tvb, offset);
 530         if (tree) {
 531                   proto_tree_add_uint(tree, hf_ssh_padding_length, tvb,
 532                     offset, 1, padding_length);
 533         }
 534         offset += 1;
 535
 536         if(tree) {
 537                 tf=proto_tree_add_text(tree,tvb,offset,-1,"Key Exchange");
 538                 key_ex_tree = proto_item_add_subtree(tf ,ett_key_exchange);
 539         }
 540         /* msg_code */
 541         msg_code = tvb_get_guint8(tvb, offset);
 542         if (tree) {
 543                   proto_tree_add_uint_format(key_ex_tree, hf_ssh_msg_code, tvb,
 544                     offset, 1, msg_code,"Msg code: %s (%u)",
 545                         val_to_str(msg_code, ssh2_msg_vals, "Unknown (%u)"),
 546                         msg_code);
 547
 548         }
 549         if (check_col(pinfo->cinfo, COL_INFO)) {
 550                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
 551                         val_to_str(msg_code, ssh2_msg_vals, "Unknown (%u)"));
 552         }
 553         offset += 1;
 554
 555         /* 16 bytes cookie  */
 556         if(number == 1) {
 557                 offset = ssh_dissect_key_init(tvb, offset,key_ex_tree);
 558         }
 559
 560         len = plen+4-padding_length-(offset-last_offset);
 561         if (tree ) {
 562                 ssh_proto_tree_add_item(key_ex_tree, hf_ssh_payload,
 563                     tvb, offset, len, FALSE);
 564         }
 565         offset +=len;
 566
 567         /* padding */
 568         if(tree) {
 569                 ssh_proto_tree_add_item(key_ex_tree, hf_ssh_padding_string,
 570                                 tvb, offset, padding_length, FALSE);
 571         }
 572         offset+= padding_length;
 573
 574         /* MAC , if there is still bytes, treat it as 16bytes MAC*/
 575         if(msg_code == SSH2_MSG_KEX_DH_GEX_REPLY) {
 576                 len = tvb_reported_length_remaining(tvb,offset);
 577                 if(len == 16) {
 578                         if(tree) {
 579                                 proto_tree_add_item(key_ex_tree, hf_ssh_mac_string,
 580                                         tvb, offset, len , FALSE);
 581                         }
 582                         offset+=len;
 583                 }
 584         }
 585
 586         return offset;
 587 }
 588 static int
 589 ssh_dissect_encrypted_packet(tvbuff_t *tvb, packet_info *pinfo,
 590                 int offset, proto_tree *tree,int is_response)
 591 {
 592         gint len;
 593
 594         len = tvb_reported_length_remaining(tvb,offset);
 595         if (check_col(pinfo->cinfo, COL_INFO)) {
 596                 col_add_fstr(pinfo->cinfo, COL_INFO, "Encrypted %s packet len=%d",
 597                         is_response?"response":"request",len);
 598         }
 599         if (tree ) {
 600                 ssh_proto_tree_add_item(tree, hf_ssh_encrypted_packet,
 601                                 tvb, offset, len, FALSE);
 602         }
 603         offset+=len;
 604         return offset;
 605 }
 606
 607 static int
 608 ssh_dissect_protocol(tvbuff_t *tvb, packet_info *pinfo,
 609                 int offset, proto_tree *tree, int is_response, int * version,
 610                 gboolean *need_desegmentation)
 611 {
 612         guint   remain_length;
 613         gint    linelen, protolen;
 614
 615         /*
 616          *  If the first packet do not contain the banner,
 617          *  it is dump in the middle of a flow or not a ssh at all
 618          */
 619         if(tvb_strncaseeql(tvb,offset,"SSH-",4) != 0 ) {
 620                 offset = ssh_dissect_encrypted_packet(tvb, pinfo,
 621                         offset,tree,is_response);
 622                 return offset;
 623         }
 624
 625         if(!is_response) {
 626                 if(tvb_strncaseeql(tvb,offset,"SSH-2.",6) == 0 ) {
 627                         *(version) = SSH_VERSION_2;
 628                 }else if(tvb_strncaseeql(tvb,offset,"SSH-1.99-",9) == 0 ) {
 629                         *(version) = SSH_VERSION_2;
 630                 }else if(tvb_strncaseeql(tvb,offset,"SSH-1.",6) == 0 ) {
 631                         *(version) = SSH_VERSION_1;
 632                }
 633         }
 634
 635         /*
 636          * We use "tvb_ensure_length_remaining()" to make sure there
 637          * actually *is* data remaining.
 638          *
 639          * This means we're guaranteed that "remain_length" is positive.
 640          */
 641         remain_length = tvb_ensure_length_remaining(tvb,offset);
 642         /*linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 643          */
 644         linelen = tvb_find_guint8(tvb, offset, -1, '\n');
 645
 646         if (ssh_desegment && pinfo->can_desegment) {
 647                 if(linelen == -1 || remain_length < (guint)linelen-offset ) {
 648                         pinfo->desegment_offset = offset;
 649                         pinfo->desegment_len = linelen-remain_length;
 650                         *need_desegmentation = TRUE;
 651                         return offset;
 652                 }
 653         }
 654         if(linelen == -1 ) {
 655                 /* XXX - reassemble across segment boundaries? */
 656                 linelen = remain_length;
 657                 protolen = linelen;
 658         } else {
 659                 linelen = linelen - offset + 1;
 660                 protolen = linelen - 1;
 661         }
 662
 663         if (check_col(pinfo->cinfo, COL_INFO)) {
 664                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s Protocol: %s",
 665                         is_response?"Server":"Client",
 666                         tvb_format_text(tvb,offset,protolen));
 667         }
 668         if (tree ) {
 669                 ssh_proto_tree_add_item(tree, hf_ssh_protocol,
 670                                 tvb, offset, linelen, FALSE);
 671         }
 672         offset+=linelen;
 673         return offset;
 674 }
 675
 676 #define SSH_PROPOSAL(item)\
 677         { &hf_ssh_ ## item, &hf_ssh_ ## item ## _length }
 678
 679 static struct {
 680         int *value, *length;
 681 } ssh_proposals[] = {
 682         SSH_PROPOSAL(kex_algorithms),
 683         SSH_PROPOSAL(server_host_key_algorithms),
 684         SSH_PROPOSAL(encryption_algorithms_client_to_server),
 685         SSH_PROPOSAL(encryption_algorithms_server_to_client),
 686         SSH_PROPOSAL(mac_algorithms_client_to_server),
 687         SSH_PROPOSAL(mac_algorithms_server_to_client),
 688         SSH_PROPOSAL(compression_algorithms_client_to_server),
 689         SSH_PROPOSAL(compression_algorithms_server_to_client),
 690         SSH_PROPOSAL(languages_client_to_server),
 691         SSH_PROPOSAL(languages_server_to_client),
 692         {NULL, NULL}
 693 };
 694
 695 static int
 696 ssh_dissect_key_init(tvbuff_t *tvb, int offset, proto_tree *tree )
 697 {
 698         guint   len;
 699         int     i;
 700
 701         proto_item *tf;
 702         proto_item *key_init_tree=NULL;
 703
 704         if (tree) {
 705                 tf=proto_tree_add_text(tree,tvb,offset,-1,"Algorithms");
 706                 key_init_tree = proto_item_add_subtree(tf, ett_key_init);
 707                 proto_tree_add_item(key_init_tree, hf_ssh_cookie,
 708                     tvb, offset, 16, FALSE);
 709         }
 710         offset += 16;
 711
 712         for (i = 0; ssh_proposals[i].value; i++) {
 713                 len = tvb_get_ntohl(tvb, offset);
 714                 if (key_init_tree) {
 715                         proto_tree_add_uint(key_init_tree,
 716                                 *ssh_proposals[i].length, tvb, offset, 4, len);
 717                 }
 718                 offset+=4;
 719                 if (key_init_tree) {
 720                         ssh_proto_tree_add_item(key_init_tree,
 721                                 *ssh_proposals[i].value, tvb, offset, len, FALSE);
 722                 }
 723                 offset+=len;
 724         }
 725         return offset;
 726 }
 727 proto_item *
 728 ssh_proto_tree_add_item(proto_tree *tree, int hfindex, tvbuff_t *tvb,
 729     gint start, gint length, gboolean little_endian)
 730 {
 731         if (tree && length <0xffff && length > 0) {
 732                 return proto_tree_add_item(tree, hfindex, tvb, start, length,little_endian);
 733         }
 734         return NULL;
 735 }
 736
 737 void
 738 proto_register_ssh(void)
 739 {
 740   static hf_register_info hf[] = {
 741     { &hf_ssh_packet_length,
 742       { "Packet Length",              "ssh.packet_length",
 743         FT_UINT32, BASE_DEC, NULL,  0x0,
 744         "SSH packet length", HFILL }},
 745
 746     { &hf_ssh_padding_length,
 747       { "Padding Length",         "ssh.padding_length",
 748         FT_UINT8, BASE_DEC, NULL, 0x0,
 749         "SSH Packet Number", HFILL }},
 750
 751     { &hf_ssh_msg_code,
 752       { "Message Code",   "ssh.message_code",
 753         FT_UINT8, BASE_DEC, NULL, 0x0,
 754         "SSH Message Code", HFILL }},
 755
 756     { &hf_ssh_cookie,
 757       { "Cookie",         "ssh.cookie",
 758         FT_BYTES, BASE_NONE, NULL, 0x0,
 759         "SSH Cookie", HFILL }},
 760
 761     { &hf_ssh_encrypted_packet,
 762       { "Encrypted Packet",       "ssh.encrypted_packet",
 763         FT_BYTES, BASE_NONE, NULL, 0x0,
 764         "SSH Protocol Packet", HFILL }},
 765
 766     { &hf_ssh_protocol,
 767       { "Protocol",       "ssh.protocol",
 768         FT_STRING, BASE_NONE, NULL, 0x0,
 769         "SSH Protocol", HFILL }},
 770
 771     { &hf_ssh_payload,
 772       { "Payload",        "ssh.payload",
 773         FT_BYTES, BASE_NONE, NULL, 0x0,
 774         "SSH Payload", HFILL }},
 775
 776     { &hf_ssh_padding_string,
 777       { "Padding String",         "ssh.padding_string",
 778         FT_STRING, BASE_NONE, NULL, 0x0,
 779         "SSH Padding String", HFILL }},
 780
 781     { &hf_ssh_mac_string,
 782       { "MAC String",     "ssh.mac_string",
 783         FT_STRING, BASE_NONE, NULL, 0x0,
 784         "SSH MAC String", HFILL }},
 785
 786   { &hf_ssh_kex_algorithms,
 787       { "kex_algorithms string",         "ssh.kex_algorithms",
 788         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 789         "SSH kex_algorithms string", HFILL }},
 790
 791   { &hf_ssh_server_host_key_algorithms,
 792       { "server_host_key_algorithms string",         "ssh.server_host_key_algorithms",
 793         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 794         "SSH server_host_key_algorithms string", HFILL }},
 795
 796   { &hf_ssh_encryption_algorithms_client_to_server,
 797       { "encryption_algorithms_client_to_server string",         "ssh.encryption_algorithms_client_to_server",
 798         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 799         "SSH encryption_algorithms_client_to_server string", HFILL }},
 800
 801   { &hf_ssh_encryption_algorithms_server_to_client,
 802       { "encryption_algorithms_server_to_client string",         "ssh.encryption_algorithms_server_to_client",
 803         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 804         "SSH encryption_algorithms_server_to_client string", HFILL }},
 805
 806   { &hf_ssh_mac_algorithms_client_to_server,
 807       { "mac_algorithms_client_to_server string",         "ssh.mac_algorithms_client_to_server",
 808         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 809         "SSH mac_algorithms_client_to_server string", HFILL }},
 810
 811   { &hf_ssh_mac_algorithms_server_to_client,
 812       { "mac_algorithms_server_to_client string",         "ssh.mac_algorithms_server_to_client",
 813         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 814         "SSH mac_algorithms_server_to_client string", HFILL }},
 815
 816   { &hf_ssh_compression_algorithms_client_to_server,
 817       { "compression_algorithms_client_to_server string",         "ssh.compression_algorithms_client_to_server",
 818         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 819         "SSH compression_algorithms_client_to_server string", HFILL }},
 820
 821   { &hf_ssh_compression_algorithms_server_to_client,
 822       { "compression_algorithms_server_to_client string",         "ssh.compression_algorithms_server_to_client",
 823         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 824         "SSH compression_algorithms_server_to_client string", HFILL }},
 825
 826   { &hf_ssh_languages_client_to_server,
 827       { "languages_client_to_server string",         "ssh.languages_client_to_server",
 828         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 829         "SSH languages_client_to_server string", HFILL }},
 830
 831   { &hf_ssh_languages_server_to_client,
 832       { "languages_server_to_client string",         "ssh.languages_server_to_client",
 833         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 834         "SSH languages_server_to_client string", HFILL }},
 835
 836   { &hf_ssh_kex_algorithms_length,
 837       { "kex_algorithms length",         "ssh.kex_algorithms_length",
 838         FT_UINT32, BASE_DEC, NULL, 0x0,
 839         "SSH kex_algorithms length", HFILL }},
 840
 841   { &hf_ssh_server_host_key_algorithms_length,
 842       { "server_host_key_algorithms length",         "ssh.server_host_key_algorithms_length",
 843         FT_UINT32, BASE_DEC, NULL, 0x0,
 844         "SSH server_host_key_algorithms length", HFILL }},
 845
 846   { &hf_ssh_encryption_algorithms_client_to_server_length,
 847       { "encryption_algorithms_client_to_server length",         "ssh.encryption_algorithms_client_to_server_length",
 848         FT_UINT32, BASE_DEC, NULL, 0x0,
 849         "SSH encryption_algorithms_client_to_server length", HFILL }},
 850
 851   { &hf_ssh_encryption_algorithms_server_to_client_length,
 852       { "encryption_algorithms_server_to_client length",         "ssh.encryption_algorithms_server_to_client_length",
 853         FT_UINT32, BASE_DEC, NULL, 0x0,
 854         "SSH encryption_algorithms_server_to_client length", HFILL }},
 855
 856   { &hf_ssh_mac_algorithms_client_to_server_length,
 857       { "mac_algorithms_client_to_server length",         "ssh.mac_algorithms_client_to_server_length",
 858         FT_UINT32, BASE_DEC, NULL, 0x0,
 859         "SSH mac_algorithms_client_to_server length", HFILL }},
 860
 861   { &hf_ssh_mac_algorithms_server_to_client_length,
 862       { "mac_algorithms_server_to_client length",         "ssh.mac_algorithms_server_to_client_length",
 863         FT_UINT32, BASE_DEC, NULL, 0x0,
 864         "SSH mac_algorithms_server_to_client length", HFILL }},
 865
 866   { &hf_ssh_compression_algorithms_client_to_server_length,
 867       { "compression_algorithms_client_to_server length",         "ssh.compression_algorithms_client_to_server_length",
 868         FT_UINT32, BASE_DEC, NULL, 0x0,
 869         "SSH compression_algorithms_client_to_server length", HFILL }},
 870
 871   { &hf_ssh_compression_algorithms_server_to_client_length,
 872       { "compression_algorithms_server_to_client length",         "ssh.compression_algorithms_server_to_client_length",
 873         FT_UINT32, BASE_DEC, NULL, 0x0,
 874         "SSH compression_algorithms_server_to_client length", HFILL }},
 875
 876   { &hf_ssh_languages_client_to_server_length,
 877       { "languages_client_to_server length",         "ssh.languages_client_to_server_length",
 878         FT_UINT32, BASE_DEC, NULL, 0x0,
 879         "SSH languages_client_to_server length", HFILL }},
 880
 881   { &hf_ssh_languages_server_to_client_length,
 882       { "languages_server_to_client length",         "ssh.languages_server_to_client_length",
 883         FT_UINT32, BASE_DEC, NULL, 0x0,
 884         "SSH languages_server_to_client length", HFILL }},
 885
 886
 887         };
 888         static gint *ett[] = {
 889                 &ett_ssh,
 890                 &ett_key_exchange,
 891                 &ett_ssh1,
 892                 &ett_ssh2,
 893                 &ett_key_init
 894         };
 895         module_t *ssh_module;
 896
 897         proto_ssh = proto_register_protocol("SSH Protocol",
 898                                        "SSH", "ssh");
 899          proto_register_field_array(proto_ssh, hf, array_length(hf));
 900         proto_register_subtree_array(ett, array_length(ett));
 901         register_init_routine(&ssh_init_protocol);
 902
 903         ssh_module = prefs_register_protocol(proto_ssh, NULL);
 904         prefs_register_bool_preference(ssh_module, "desegment_buffers",
 905                 "Desegment all SSH buffers spanning multiple TCP segments",
 906                 "Whether the SSH dissector should desegment all SSH buffers spanning multiple TCP segments",
 907                 &ssh_desegment);
 908 }
 909
 910 void
 911 proto_reg_handoff_ssh(void)
 912 {
 913         dissector_handle_t ssh_handle;
 914
 915         ssh_handle = create_dissector_handle(dissect_ssh, proto_ssh);
 916
 917         dissector_add("tcp.port", TCP_PORT_SSH, ssh_handle);
 918 }