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 1.8 2003/12/23 21:16:27 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                         switch(version) {
 322
 323                         case SSH_VERSION_UNKNOWN:
 324                                 /*
 325                                  * We use "tvb_ensure_length_remaining()"
 326                                  * to make sure there actually *is* data
 327                                  * remaining.
 328                                  *
 329                                  * This means we're guaranteed that
 330                                  * "remain_length" is positive.
 331                                  */
 332                                 remain_length = tvb_ensure_length_remaining(tvb,
 333                                     offset);
 334                                 proto_tree_add_text(ssh_tree, tvb, offset,
 335                                                 remain_length,
 336                                                 "Unknown SSH version data");
 337                                 offset += remain_length;
 338                                 break;
 339
 340                         case SSH_VERSION_1:
 341                                 offset = ssh_dissect_ssh1(tvb, pinfo,
 342                                                 offset,ssh_tree,is_response,this_number,
 343                                                 &need_desegmentation);
 344                                 break;
 345
 346                         case SSH_VERSION_2:
 347                                 offset = ssh_dissect_ssh2(tvb, pinfo,
 348                                                 offset,ssh_tree,is_response,this_number,
 349                                                 &need_desegmentation);
 350                                 break;
 351                         }
 352                 }
 353
 354                 if(need_desegmentation) return;
 355         }
 356 }
 357
 358 static int
 359 ssh_dissect_ssh2(tvbuff_t *tvb, packet_info *pinfo,
 360                 int offset, proto_tree *tree,int is_response, int this_number,
 361                 gboolean *need_desegmentation)
 362 {
 363         proto_item *ti;
 364         proto_item *ssh2_tree=NULL;
 365
 366         if(tree) {
 367                 ti=proto_tree_add_text(tree,tvb,offset,-1,"SSH Version 2");
 368                 ssh2_tree = proto_item_add_subtree(ti ,ett_ssh2);
 369         }
 370
 371         if((is_response && this_number > 3) || (!is_response && this_number>4)) {
 372                 offset = ssh_dissect_encrypted_packet(tvb, pinfo,
 373                                 offset,ssh2_tree,is_response);
 374         } else {
 375                 offset = ssh_dissect_key_exchange(tvb,pinfo,
 376                         offset,ssh2_tree,is_response,this_number,
 377                         need_desegmentation);
 378         }
 379
 380         return offset;
 381 }
 382 static int
 383 ssh_dissect_ssh1(tvbuff_t *tvb, packet_info *pinfo,
 384                 int offset, proto_tree *tree,int is_response,
 385                 int number, gboolean *need_desegmentation)
 386 {
 387         guint   plen, padding_length,len;
 388         guint8  msg_code;
 389         guint   remain_length;
 390
 391         proto_item *ti;
 392         proto_item *ssh1_tree =NULL;
 393
 394         if(tree) {
 395                 ti=proto_tree_add_text(tree,tvb,offset,-1,"SSH Version 1");
 396                 ssh1_tree = proto_item_add_subtree(ti ,ett_ssh1);
 397         }
 398
 399         /*
 400          * We use "tvb_ensure_length_remaining()" to make sure there
 401          * actually *is* data remaining.
 402          *
 403          * This means we're guaranteed that "remain_length" is positive.
 404          */
 405         remain_length = tvb_ensure_length_remaining(tvb,offset);
 406         if (ssh_desegment && pinfo->can_desegment) {
 407                 if(remain_length < 4) {
 408                         pinfo->desegment_offset = offset;
 409                         pinfo->desegment_len = 4-remain_length;
 410                         *need_desegmentation = TRUE;
 411                         return offset;
 412                 }
 413         }
 414         plen = tvb_get_ntohl(tvb, offset) ;
 415         padding_length  = 8 - plen%8;
 416
 417
 418         if (ssh_desegment && pinfo->can_desegment) {
 419                 if(plen+4+padding_length >  remain_length ) {
 420                         pinfo->desegment_offset = offset;
 421                         pinfo->desegment_len = plen+padding_length - remain_length;
 422                         *need_desegmentation = TRUE;
 423                         return offset;
 424                 }
 425         }
 426
 427         if (check_col(pinfo->cinfo, COL_INFO)) {
 428                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s: ",
 429                         is_response?"Server":"Client");
 430         }
 431
 432         if(plen >= 0xffff) {
 433                 if (ssh1_tree && plen > 0) {
 434                           proto_tree_add_uint_format(ssh1_tree, hf_ssh_packet_length, tvb,
 435                             offset, 4, plen,"Overly large length %x",plen);
 436                 }
 437                 plen = remain_length-4-padding_length;
 438         } else {
 439                 if (ssh1_tree && plen > 0) {
 440                           proto_tree_add_uint(ssh1_tree, hf_ssh_packet_length, tvb,
 441                             offset, 4, plen);
 442                 }
 443         }
 444         offset+=4;
 445 /* padding length */
 446
 447         if (tree) {
 448                   proto_tree_add_uint(ssh1_tree, hf_ssh_padding_length, tvb,
 449                     offset, padding_length, padding_length);
 450         }
 451         offset += padding_length;
 452 /*
 453         if(tree) {
 454                 tf=proto_tree_add_text(tree,tvb,offset,-1,"SSH Version 1");
 455                 ssh1_tree = proto_item_add_subtree(tf ,ett_ssh1);
 456         }
 457 */
 458         /* msg_code */
 459         if(number == 1 ) {
 460                 msg_code = tvb_get_guint8(tvb, offset);
 461                 if (tree) {
 462                         proto_tree_add_uint_format(ssh1_tree, hf_ssh_msg_code, tvb,
 463                                 offset, 1, msg_code,"Msg code: %s (%u)",
 464                                 val_to_str(msg_code, ssh1_msg_vals, "Unknown (%u)"),
 465                                 msg_code);
 466                 }
 467                 if (check_col(pinfo->cinfo, COL_INFO)) {
 468                         col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
 469                         val_to_str(msg_code, ssh1_msg_vals, "Unknown (%u)"));
 470                 }
 471                 offset += 1;
 472                 len = plen -1;
 473         } else {
 474                 len = plen;
 475                 if (check_col(pinfo->cinfo, COL_INFO)) {
 476                         col_append_fstr(pinfo->cinfo, COL_INFO, "Encrypted packet len=%d", len);
 477                 }
 478         }
 479         /* payload */
 480         if (ssh1_tree ) {
 481                 ssh_proto_tree_add_item(ssh1_tree, hf_ssh_payload,
 482                     tvb, offset, len, FALSE);
 483         }
 484         offset+=len;
 485
 486         return offset;
 487 }
 488
 489 static int
 490 ssh_dissect_key_exchange(tvbuff_t *tvb, packet_info *pinfo,
 491                 int offset, proto_tree *tree,int is_response,int number,
 492                 gboolean *need_desegmentation)
 493 {
 494         guint   plen,len;
 495         guint8  padding_length;
 496         guint   remain_length;
 497         int     last_offset=offset;
 498         guint   msg_code;
 499
 500         proto_item *tf;
 501         proto_item *key_ex_tree =NULL;
 502
 503         /*
 504          * We use "tvb_ensure_length_remaining()" to make sure there
 505          * actually *is* data remaining.
 506          *
 507          * This means we're guaranteed that "remain_length" is positive.
 508          */
 509         remain_length = tvb_ensure_length_remaining(tvb,offset);
 510         if (ssh_desegment && pinfo->can_desegment) {
 511                 if(remain_length < 4) {
 512                         pinfo->desegment_offset = offset;
 513                         pinfo->desegment_len = 4-remain_length;
 514                         *need_desegmentation = TRUE;
 515                         return offset;
 516                 }
 517         }
 518         plen = tvb_get_ntohl(tvb, offset) ;
 519
 520         if (ssh_desegment && pinfo->can_desegment) {
 521                 if(plen +4 >  remain_length ) {
 522                         pinfo->desegment_offset = offset;
 523                         pinfo->desegment_len = plen+4 - remain_length;
 524                         *need_desegmentation = TRUE;
 525                         return offset;
 526                 }
 527         }
 528         /*
 529          * Need to check plen > 0x80000000 here
 530          */
 531
 532         if (check_col(pinfo->cinfo, COL_INFO)) {
 533                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s: ",
 534                         is_response?"Server":"Client");
 535         }
 536
 537         if(plen >= 0xffff) {
 538                 if (tree) {
 539                         proto_tree_add_uint_format(tree, hf_ssh_packet_length, tvb,
 540                                 offset, 4, plen,"Overly large number 0x%x",plen);
 541                 }
 542                 plen = remain_length-4;
 543         } else {
 544                 if (tree) {
 545                         proto_tree_add_uint(tree, hf_ssh_packet_length, tvb,
 546                                 offset, 4, plen);
 547                 }
 548         }
 549         offset+=4;
 550 /* padding length */
 551         padding_length = tvb_get_guint8(tvb, offset);
 552         if (tree) {
 553                   proto_tree_add_uint(tree, hf_ssh_padding_length, tvb,
 554                     offset, 1, padding_length);
 555         }
 556         offset += 1;
 557
 558         if(tree) {
 559                 tf=proto_tree_add_text(tree,tvb,offset,-1,"Key Exchange");
 560                 key_ex_tree = proto_item_add_subtree(tf ,ett_key_exchange);
 561         }
 562         /* msg_code */
 563         msg_code = tvb_get_guint8(tvb, offset);
 564         if (tree) {
 565                   proto_tree_add_uint_format(key_ex_tree, hf_ssh_msg_code, tvb,
 566                     offset, 1, msg_code,"Msg code: %s (%u)",
 567                         val_to_str(msg_code, ssh2_msg_vals, "Unknown (%u)"),
 568                         msg_code);
 569
 570         }
 571         if (check_col(pinfo->cinfo, COL_INFO)) {
 572                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
 573                         val_to_str(msg_code, ssh2_msg_vals, "Unknown (%u)"));
 574         }
 575         offset += 1;
 576
 577         /* 16 bytes cookie  */
 578         if(number == 1) {
 579                 offset = ssh_dissect_key_init(tvb, offset,key_ex_tree);
 580         }
 581
 582         len = plen+4-padding_length-(offset-last_offset);
 583         if (tree ) {
 584                 ssh_proto_tree_add_item(key_ex_tree, hf_ssh_payload,
 585                     tvb, offset, len, FALSE);
 586         }
 587         offset +=len;
 588
 589         /* padding */
 590         if(tree) {
 591                 ssh_proto_tree_add_item(key_ex_tree, hf_ssh_padding_string,
 592                                 tvb, offset, padding_length, FALSE);
 593         }
 594         offset+= padding_length;
 595
 596         /* MAC , if there is still bytes, treat it as 16bytes MAC*/
 597         if(msg_code == SSH2_MSG_KEX_DH_GEX_REPLY) {
 598                 len = tvb_reported_length_remaining(tvb,offset);
 599                 if(len == 16) {
 600                         if(tree) {
 601                                 proto_tree_add_item(key_ex_tree, hf_ssh_mac_string,
 602                                         tvb, offset, len , FALSE);
 603                         }
 604                         offset+=len;
 605                 }
 606         }
 607
 608         return offset;
 609 }
 610 static int
 611 ssh_dissect_encrypted_packet(tvbuff_t *tvb, packet_info *pinfo,
 612                 int offset, proto_tree *tree,int is_response)
 613 {
 614         gint len;
 615
 616         len = tvb_reported_length_remaining(tvb,offset);
 617         if (check_col(pinfo->cinfo, COL_INFO)) {
 618                 col_add_fstr(pinfo->cinfo, COL_INFO, "Encrypted %s packet len=%d",
 619                         is_response?"response":"request",len);
 620         }
 621         if (tree ) {
 622                 ssh_proto_tree_add_item(tree, hf_ssh_encrypted_packet,
 623                                 tvb, offset, len, FALSE);
 624         }
 625         offset+=len;
 626         return offset;
 627 }
 628
 629 static int
 630 ssh_dissect_protocol(tvbuff_t *tvb, packet_info *pinfo,
 631                 int offset, proto_tree *tree, int is_response, int * version,
 632                 gboolean *need_desegmentation)
 633 {
 634         guint   remain_length;
 635         gint    linelen, protolen;
 636
 637         /*
 638          *  If the first packet do not contain the banner,
 639          *  it is dump in the middle of a flow or not a ssh at all
 640          */
 641         if(tvb_strncaseeql(tvb,offset,"SSH-",4) != 0 ) {
 642                 offset = ssh_dissect_encrypted_packet(tvb, pinfo,
 643                         offset,tree,is_response);
 644                 return offset;
 645         }
 646
 647         if(!is_response) {
 648                 if(tvb_strncaseeql(tvb,offset,"SSH-2.",6) == 0 ) {
 649                         *(version) = SSH_VERSION_2;
 650                 }else if(tvb_strncaseeql(tvb,offset,"SSH-1.99-",9) == 0 ) {
 651                         *(version) = SSH_VERSION_2;
 652                 }else if(tvb_strncaseeql(tvb,offset,"SSH-1.",6) == 0 ) {
 653                         *(version) = SSH_VERSION_1;
 654                }
 655         }
 656
 657         /*
 658          * We use "tvb_ensure_length_remaining()" to make sure there
 659          * actually *is* data remaining.
 660          *
 661          * This means we're guaranteed that "remain_length" is positive.
 662          */
 663         remain_length = tvb_ensure_length_remaining(tvb,offset);
 664         /*linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 665          */
 666         linelen = tvb_find_guint8(tvb, offset, -1, '\n');
 667
 668         if (ssh_desegment && pinfo->can_desegment) {
 669                 if(linelen == -1 || remain_length < (guint)linelen-offset ) {
 670                         pinfo->desegment_offset = offset;
 671                         pinfo->desegment_len = linelen-remain_length;
 672                         *need_desegmentation = TRUE;
 673                         return offset;
 674                 }
 675         }
 676         if(linelen == -1 ) {
 677                 /* XXX - reassemble across segment boundaries? */
 678                 linelen = remain_length;
 679                 protolen = linelen;
 680         } else {
 681                 linelen = linelen - offset + 1;
 682                 protolen = linelen - 1;
 683         }
 684
 685         if (check_col(pinfo->cinfo, COL_INFO)) {
 686                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s Protocol: %s",
 687                         is_response?"Server":"Client",
 688                         tvb_format_text(tvb,offset,protolen));
 689         }
 690         if (tree ) {
 691                 ssh_proto_tree_add_item(tree, hf_ssh_protocol,
 692                                 tvb, offset, linelen, FALSE);
 693         }
 694         offset+=linelen;
 695         return offset;
 696 }
 697
 698 #define SSH_PROPOSAL(item)\
 699         { &hf_ssh_ ## item, &hf_ssh_ ## item ## _length }
 700
 701 static struct {
 702         int *value, *length;
 703 } ssh_proposals[] = {
 704         SSH_PROPOSAL(kex_algorithms),
 705         SSH_PROPOSAL(server_host_key_algorithms),
 706         SSH_PROPOSAL(encryption_algorithms_client_to_server),
 707         SSH_PROPOSAL(encryption_algorithms_server_to_client),
 708         SSH_PROPOSAL(mac_algorithms_client_to_server),
 709         SSH_PROPOSAL(mac_algorithms_server_to_client),
 710         SSH_PROPOSAL(compression_algorithms_client_to_server),
 711         SSH_PROPOSAL(compression_algorithms_server_to_client),
 712         SSH_PROPOSAL(languages_client_to_server),
 713         SSH_PROPOSAL(languages_server_to_client),
 714         {NULL, NULL}
 715 };
 716
 717 static int
 718 ssh_dissect_key_init(tvbuff_t *tvb, int offset, proto_tree *tree )
 719 {
 720         guint   len;
 721         int     i;
 722
 723         proto_item *tf;
 724         proto_item *key_init_tree=NULL;
 725
 726         if (tree) {
 727                 tf=proto_tree_add_text(tree,tvb,offset,-1,"Algorithms");
 728                 key_init_tree = proto_item_add_subtree(tf, ett_key_init);
 729                 proto_tree_add_item(key_init_tree, hf_ssh_cookie,
 730                     tvb, offset, 16, FALSE);
 731         }
 732         offset += 16;
 733
 734         for (i = 0; ssh_proposals[i].value; i++) {
 735                 len = tvb_get_ntohl(tvb, offset);
 736                 if (key_init_tree) {
 737                         proto_tree_add_uint(key_init_tree,
 738                                 *ssh_proposals[i].length, tvb, offset, 4, len);
 739                 }
 740                 offset+=4;
 741                 if (key_init_tree) {
 742                         ssh_proto_tree_add_item(key_init_tree,
 743                                 *ssh_proposals[i].value, tvb, offset, len, FALSE);
 744                 }
 745                 offset+=len;
 746         }
 747         return offset;
 748 }
 749 proto_item *
 750 ssh_proto_tree_add_item(proto_tree *tree, int hfindex, tvbuff_t *tvb,
 751     gint start, gint length, gboolean little_endian)
 752 {
 753         if (tree && length <0xffff && length > 0) {
 754                 return proto_tree_add_item(tree, hfindex, tvb, start, length,little_endian);
 755         }
 756         return NULL;
 757 }
 758
 759 void
 760 proto_register_ssh(void)
 761 {
 762   static hf_register_info hf[] = {
 763     { &hf_ssh_packet_length,
 764       { "Packet Length",              "ssh.packet_length",
 765         FT_UINT32, BASE_DEC, NULL,  0x0,
 766         "SSH packet length", HFILL }},
 767
 768     { &hf_ssh_padding_length,
 769       { "Padding Length",         "ssh.padding_length",
 770         FT_UINT8, BASE_DEC, NULL, 0x0,
 771         "SSH Packet Number", HFILL }},
 772
 773     { &hf_ssh_msg_code,
 774       { "Message Code",   "ssh.message_code",
 775         FT_UINT8, BASE_DEC, NULL, 0x0,
 776         "SSH Message Code", HFILL }},
 777
 778     { &hf_ssh_cookie,
 779       { "Cookie",         "ssh.cookie",
 780         FT_BYTES, BASE_NONE, NULL, 0x0,
 781         "SSH Cookie", HFILL }},
 782
 783     { &hf_ssh_encrypted_packet,
 784       { "Encrypted Packet",       "ssh.encrypted_packet",
 785         FT_BYTES, BASE_NONE, NULL, 0x0,
 786         "SSH Protocol Packet", HFILL }},
 787
 788     { &hf_ssh_protocol,
 789       { "Protocol",       "ssh.protocol",
 790         FT_STRING, BASE_NONE, NULL, 0x0,
 791         "SSH Protocol", HFILL }},
 792
 793     { &hf_ssh_payload,
 794       { "Payload",        "ssh.payload",
 795         FT_BYTES, BASE_NONE, NULL, 0x0,
 796         "SSH Payload", HFILL }},
 797
 798     { &hf_ssh_padding_string,
 799       { "Padding String",         "ssh.padding_string",
 800         FT_STRING, BASE_NONE, NULL, 0x0,
 801         "SSH Padding String", HFILL }},
 802
 803     { &hf_ssh_mac_string,
 804       { "MAC String",     "ssh.mac_string",
 805         FT_STRING, BASE_NONE, NULL, 0x0,
 806         "SSH MAC String", HFILL }},
 807
 808   { &hf_ssh_kex_algorithms,
 809       { "kex_algorithms string",         "ssh.kex_algorithms",
 810         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 811         "SSH kex_algorithms string", HFILL }},
 812
 813   { &hf_ssh_server_host_key_algorithms,
 814       { "server_host_key_algorithms string",         "ssh.server_host_key_algorithms",
 815         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 816         "SSH server_host_key_algorithms string", HFILL }},
 817
 818   { &hf_ssh_encryption_algorithms_client_to_server,
 819       { "encryption_algorithms_client_to_server string",         "ssh.encryption_algorithms_client_to_server",
 820         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 821         "SSH encryption_algorithms_client_to_server string", HFILL }},
 822
 823   { &hf_ssh_encryption_algorithms_server_to_client,
 824       { "encryption_algorithms_server_to_client string",         "ssh.encryption_algorithms_server_to_client",
 825         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 826         "SSH encryption_algorithms_server_to_client string", HFILL }},
 827
 828   { &hf_ssh_mac_algorithms_client_to_server,
 829       { "mac_algorithms_client_to_server string",         "ssh.mac_algorithms_client_to_server",
 830         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 831         "SSH mac_algorithms_client_to_server string", HFILL }},
 832
 833   { &hf_ssh_mac_algorithms_server_to_client,
 834       { "mac_algorithms_server_to_client string",         "ssh.mac_algorithms_server_to_client",
 835         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 836         "SSH mac_algorithms_server_to_client string", HFILL }},
 837
 838   { &hf_ssh_compression_algorithms_client_to_server,
 839       { "compression_algorithms_client_to_server string",         "ssh.compression_algorithms_client_to_server",
 840         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 841         "SSH compression_algorithms_client_to_server string", HFILL }},
 842
 843   { &hf_ssh_compression_algorithms_server_to_client,
 844       { "compression_algorithms_server_to_client string",         "ssh.compression_algorithms_server_to_client",
 845         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 846         "SSH compression_algorithms_server_to_client string", HFILL }},
 847
 848   { &hf_ssh_languages_client_to_server,
 849       { "languages_client_to_server string",         "ssh.languages_client_to_server",
 850         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 851         "SSH languages_client_to_server string", HFILL }},
 852
 853   { &hf_ssh_languages_server_to_client,
 854       { "languages_server_to_client string",         "ssh.languages_server_to_client",
 855         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 856         "SSH languages_server_to_client string", HFILL }},
 857
 858   { &hf_ssh_kex_algorithms_length,
 859       { "kex_algorithms length",         "ssh.kex_algorithms_length",
 860         FT_UINT32, BASE_DEC, NULL, 0x0,
 861         "SSH kex_algorithms length", HFILL }},
 862
 863   { &hf_ssh_server_host_key_algorithms_length,
 864       { "server_host_key_algorithms length",         "ssh.server_host_key_algorithms_length",
 865         FT_UINT32, BASE_DEC, NULL, 0x0,
 866         "SSH server_host_key_algorithms length", HFILL }},
 867
 868   { &hf_ssh_encryption_algorithms_client_to_server_length,
 869       { "encryption_algorithms_client_to_server length",         "ssh.encryption_algorithms_client_to_server_length",
 870         FT_UINT32, BASE_DEC, NULL, 0x0,
 871         "SSH encryption_algorithms_client_to_server length", HFILL }},
 872
 873   { &hf_ssh_encryption_algorithms_server_to_client_length,
 874       { "encryption_algorithms_server_to_client length",         "ssh.encryption_algorithms_server_to_client_length",
 875         FT_UINT32, BASE_DEC, NULL, 0x0,
 876         "SSH encryption_algorithms_server_to_client length", HFILL }},
 877
 878   { &hf_ssh_mac_algorithms_client_to_server_length,
 879       { "mac_algorithms_client_to_server length",         "ssh.mac_algorithms_client_to_server_length",
 880         FT_UINT32, BASE_DEC, NULL, 0x0,
 881         "SSH mac_algorithms_client_to_server length", HFILL }},
 882
 883   { &hf_ssh_mac_algorithms_server_to_client_length,
 884       { "mac_algorithms_server_to_client length",         "ssh.mac_algorithms_server_to_client_length",
 885         FT_UINT32, BASE_DEC, NULL, 0x0,
 886         "SSH mac_algorithms_server_to_client length", HFILL }},
 887
 888   { &hf_ssh_compression_algorithms_client_to_server_length,
 889       { "compression_algorithms_client_to_server length",         "ssh.compression_algorithms_client_to_server_length",
 890         FT_UINT32, BASE_DEC, NULL, 0x0,
 891         "SSH compression_algorithms_client_to_server length", HFILL }},
 892
 893   { &hf_ssh_compression_algorithms_server_to_client_length,
 894       { "compression_algorithms_server_to_client length",         "ssh.compression_algorithms_server_to_client_length",
 895         FT_UINT32, BASE_DEC, NULL, 0x0,
 896         "SSH compression_algorithms_server_to_client length", HFILL }},
 897
 898   { &hf_ssh_languages_client_to_server_length,
 899       { "languages_client_to_server length",         "ssh.languages_client_to_server_length",
 900         FT_UINT32, BASE_DEC, NULL, 0x0,
 901         "SSH languages_client_to_server length", HFILL }},
 902
 903   { &hf_ssh_languages_server_to_client_length,
 904       { "languages_server_to_client length",         "ssh.languages_server_to_client_length",
 905         FT_UINT32, BASE_DEC, NULL, 0x0,
 906         "SSH languages_server_to_client length", HFILL }},
 907
 908
 909         };
 910         static gint *ett[] = {
 911                 &ett_ssh,
 912                 &ett_key_exchange,
 913                 &ett_ssh1,
 914                 &ett_ssh2,
 915                 &ett_key_init
 916         };
 917         module_t *ssh_module;
 918
 919         proto_ssh = proto_register_protocol("SSH Protocol",
 920                                        "SSH", "ssh");
 921          proto_register_field_array(proto_ssh, hf, array_length(hf));
 922         proto_register_subtree_array(ett, array_length(ett));
 923         register_init_routine(&ssh_init_protocol);
 924
 925         ssh_module = prefs_register_protocol(proto_ssh, NULL);
 926         prefs_register_bool_preference(ssh_module, "desegment_buffers",
 927                 "Desegment all SSH buffers spanning multiple TCP segments",
 928                 "Whether the SSH dissector should desegment all SSH buffers spanning multiple TCP segments",
 929                 &ssh_desegment);
 930 }
 931
 932 void
 933 proto_reg_handoff_ssh(void)
 934 {
 935         dissector_handle_t ssh_handle;
 936
 937         ssh_handle = create_dissector_handle(dissect_ssh, proto_ssh);
 938
 939         dissector_add("tcp.port", TCP_PORT_SSH, ssh_handle);
 940 }