packet-multipart.c

   1 /* packet-multipart.c
   2  * Routines for multipart media encapsulation dissection
   3  * Copyright 2004, Anders Broman.
   4  * Copyright 2004, Olivier Biot.
   5  *
   6  * $Id: packet-multipart.c,v 1.8 2004/03/08 22:03:59 obiot Exp $
   7  *
   8  * Refer to the AUTHORS file or the AUTHORS section in the man page
   9  * for contacting the author(s) of this file.
  10  *
  11  * Ethereal - Network traffic analyzer
  12  * By Gerald Combs <gerald@ethereal.com>
  13  * Copyright 1998 Gerald Combs
  14  *
  15  *
  16  * This program is free software; you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License
  18  * as published by the Free Software Foundation; either version 2
  19  * of the License, or (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software
  28  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  29  *
  30  * References for "media-type multipart/mixed :
  31  * http://www.iana.org/assignments/media-types/index.html
  32  * http://www.rfc-editor.org/rfc/rfc2045.txt
  33  * http://www.rfc-editor.org/rfc/rfc2046.txt
  34  * http://www.rfc-editor.org/rfc/rfc2047.txt
  35  * http://www.rfc-editor.org/rfc/rfc2048.txt
  36  * http://www.rfc-editor.org/rfc/rfc2049.txt
  37  *
  38  * Part of the code is modeled from the SIP and HTTP dissectors
  39  *
  40  * General format of a MIME multipart document:
  41  *              [ preamble line-end ]
  42  *              dash-boundary transport-padding line-end
  43  *              body-part
  44  *              *encapsulation
  45  *              close-delimiter transport-padding
  46  *              [ line-end epilogue ]
  47  *
  48  * Where:
  49  *              dash-boundary     := "--" boundary
  50  *              encapsulation     := delimiter transport-padding line-end body-part
  51  *              delimiter         := line-end body-part
  52  *              close-delimiter   := delimiter "--"
  53  *              body-part         := MIME-part-headers [ line-end *OCTET ]
  54  *              transport-padding := *LWSP-char
  55  *
  56  * Note that line-end is often a LF instead of a CRLF.
  57 */
  58
  59 #ifdef HAVE_CONFIG_H
  60 #include "config.h"
  61 #endif
  62
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #include "prefs.h"
  67 #include <glib.h>
  68 #include <ctype.h>
  69
  70 #ifdef NEED_SNPRINTF_H
  71 # include "snprintf.h"
  72 #endif
  73
  74 #include <epan/packet.h>
  75
  76 /* Dissector table for media requiring special attention in multipart
  77  * encapsulation. */
  78 static dissector_table_t multipart_media_subdissector_table;
  79
  80 /* Initialize the protocol and registered fields */
  81 static int proto_multipart = -1;
  82
  83 /* Initialize the subtree pointers */
  84 static gint ett_multipart = -1;
  85 static gint ett_multipart_main = -1;
  86 static gint ett_multipart_body = -1;
  87
  88 /* Not sure that compact_name exists for multipart, but choose to keep
  89  * the structure from SIP dissector, all the content- is also from SIP */
  90
  91
  92 static const char *multipart_headers[] = {
  93         "Unknown-header",               /* Pad so that the real headers start at index 1 */
  94         "Content-Disposition",
  95         "Content-Encoding",
  96         "Content-Language",
  97         "Content-Length",
  98         "Content-Type",
  99 };
 100
 101 #define POS_CONTENT_DISPOSITION         1
 102 #define POS_CONTENT_ENCODING            2
 103 #define POS_CONTENT_LANGUAGE            3
 104 #define POS_CONTENT_LENGTH                      4
 105 #define POS_CONTENT_TYPE                        5
 106
 107 /* Initialize the header fields */
 108 static gint hf_multipart_type = -1;
 109 static gint hf_header_array[] = {
 110         -1, /* "Unknown-header" - Pad so that the real headers start at index 1 */
 111         -1, /* "Content-Disposition" */
 112         -1, /* "Content-Encoding" */
 113         -1, /* "Content-Language" */
 114         -1, /* "Content-Length" */
 115         -1, /* "Content-Type" */
 116 };
 117
 118 /* Define media_type/Content type table */
 119 static dissector_table_t media_type_dissector_table;
 120
 121 /* Data dissector handle */
 122 static dissector_handle_t data_handle;
 123
 124 /* Determins if bodies with no media type dissector shoud be displayed
 125  * as raw text, may cause problems with images sound etc
 126  * TODO improve to check for different content types ?
 127  */
 128 static gboolean display_unknown_body_as_text = FALSE;
 129
 130
 131 typedef struct {
 132         const char *type; /* Type of multipart */
 133         char *boundary; /* Boundary string (enclosing quotes removed if any) */
 134         guint boundary_length; /* Length of the boundary string */
 135 } multipart_info_t;
 136
 137
 138
 139 static gint
 140 find_first_boundary(tvbuff_t *tvb, gint start, const guint8 *boundary,
 141                 gint boundary_len, gint *boundary_line_len, gboolean *last_boundary);
 142 static gint
 143 find_next_boundary(tvbuff_t *tvb, gint start, const guint8 *boundary,
 144                 gint boundary_len, gint *boundary_line_len, gboolean *last_boundary);
 145 static gint
 146 process_preamble(proto_tree *tree, tvbuff_t *tvb, const guint8 *boundary,
 147                 gint boundary_len, gboolean *last_boundary);
 148 static gint
 149 process_body_part(proto_tree *tree, tvbuff_t *tvb, const guint8 *boundary,
 150                 gint boundary_len, packet_info *pinfo, gint start,
 151                 gboolean *last_boundary);
 152 static gint
 153 is_known_multipart_header(const char *header_str, guint len);
 154 static gint
 155 index_of_char(const char *str, const char c);
 156 char *
 157 unfold_and_compact_mime_header(const char *lines, gint *first_colon_offset);
 158
 159 /*
 160  * Unfold and clean up a MIME-like header, and process LWS as follows:
 161  *              o Preserves LWS in quoted text
 162  *              o Remove LWS before and after a separator
 163  *              o Remove trailing LWS
 164  *              o Replace other LWS with a single space
 165  * Set value to the start of the value
 166  * Return the cleaned-up RFC2822 header (buffer must be freed).
 167  */
 168 char *
 169 unfold_and_compact_mime_header(const char *lines, gint *first_colon_offset)
 170 {
 171         const char *p = lines;
 172         char c;
 173         char *ret, *q;
 174         char sep_seen = 0; /* Did we see a separator ":;," */
 175         char lws = FALSE; /* Did we see LWS (incl. folding) */
 176         gint colon = -1;
 177
 178         if (! lines) return NULL;
 179
 180         c = *p;
 181         ret = g_malloc(strlen(lines) + 1);
 182         q = ret;
 183
 184         while (c) {
 185                 if (c == ':') {
 186                         lws = FALSE; /* Prevent leading LWS from showing up */
 187                         if (colon == -1) {/* First colon */
 188                                 colon = q - ret;
 189                         }
 190                         *(q++) = sep_seen = c;
 191                         p++;
 192                 } else if (c == ';' || c == ',' || c == '=') {
 193                         lws = FALSE; /* Prevent leading LWS from showing up */
 194                         *(q++) = sep_seen = c;
 195                         p++;
 196                 } else if (c == ' ' || c == '\t') {
 197                         lws = TRUE;
 198                         p++;
 199                 } else if (c == '\n') {
 200                         lws = FALSE; /* Skip trailing LWS */
 201                         if ((c = *(p+1))) {
 202                                 if (c == ' ' || c == '\t') { /* Header unfolding */
 203                                         lws = TRUE;
 204                                         p += 2;
 205                                 } else {
 206                                         *q = c = 0; /* Stop */
 207                                 }
 208                         }
 209                 } else if (c == '\r') {
 210                         lws = FALSE;
 211                         if ((c = *(p+1))) {
 212                                 if (c == '\n') {
 213                                         if ((c = *(p+2))) {
 214                                                 if (c == ' ' || c == '\t') { /* Header unfolding */
 215                                                         lws = TRUE;
 216                                                         p += 3;
 217                                                 } else {
 218                                                         *q = c = 0; /* Stop */
 219                                                 }
 220                                         }
 221                                 } else if (c == ' ' || c == '\t') { /* Header unfolding */
 222                                         lws = TRUE;
 223                                         p += 2;
 224                                 } else {
 225                                         *q = c = 0; /* Stop */
 226                                 }
 227                         }
 228                 } else if (c == '"') { /* Start of quoted-string */
 229                         lws = FALSE;
 230                         *(q++) = c;
 231                         while (c) {
 232                                 c = *(q++) = *(++p);
 233                                 if (c == '"') {
 234                                         p++; /* Skip closing quote */
 235                                         break;
 236                                 }
 237                         }
 238                 } else { /* Regular character */
 239                         if (sep_seen) {
 240                                 sep_seen = 0;
 241                                 lws = FALSE;
 242                         } else {
 243                                 if (lws) {
 244                                         *(q++) = ' ';
 245                                         lws = FALSE;
 246                                 }
 247                         }
 248                         lws = FALSE;
 249                         *(q++) = c;
 250                         p++; /* OK */
 251                 }
 252
 253                 if (c) {
 254                         c = *p;
 255                 }
 256         }
 257         *q = 0;
 258
 259         *first_colon_offset = colon;
 260         return (ret);
 261 }
 262
 263 /* Return the index of a given char in the given string,
 264  * or -1 if not found.
 265  */
 266 static gint
 267 index_of_char(const char *str, const char c)
 268 {
 269         gint len = 0;
 270         const char *p = str;
 271
 272         while (*p && *p != c) {
 273                 p++;
 274                 len++;
 275         }
 276
 277         if (*p)
 278                 return len;
 279         return -1;
 280 }
 281
 282 /* Retrieve the media information from pinfo->private_data,
 283  * and compute the boundary string and its length.
 284  * Return a pointer to a filled-in multipart_info_t, or NULL on failure.
 285  *
 286  * Boundary delimiters must not appear within the encapsulated material,
 287  * and must be no longer than 70 characters, not counting the two
 288  * leading hyphens. (quote from rfc2046)
 289  */
 290 static multipart_info_t *
 291 get_multipart_info(packet_info *pinfo)
 292 {
 293         const char *start, *p;
 294         int len = 0;
 295         multipart_info_t *m_info = NULL;
 296         const char *type = pinfo->match_string;
 297         const char *parameters = pinfo->private_data;
 298         gint dummy;
 299
 300         if ((type == NULL) || (parameters == NULL)) {
 301                 /*
 302                  * We need both a content type AND parameters
 303                  * for multipart dissection.
 304                  */
 305                 return NULL;
 306         }
 307
 308         /* Clean up the parameters */
 309         parameters = unfold_and_compact_mime_header(parameters, &dummy);
 310
 311         /*
 312          * Process the private data
 313          * The parameters must contain the boundary string
 314          */
 315         p = parameters;
 316         while (*p) {
 317                 if (strncasecmp(p, "boundary=", 9) == 0)
 318                         break;
 319                 /* Skip to next parameter */
 320                 p = strchr(p, ';');
 321                 if (p == NULL)
 322                         return NULL;
 323                 p++; /* Skip semicolon */
 324                 while ((*p) && isspace((guchar)*p))
 325                         p++; /* Skip white space */
 326         }
 327         start = p + 9;
 328         if (start[0] == 0) {
 329                 return NULL;
 330         }
 331
 332         /*
 333          * Process the parameter value
 334          */
 335         if (start[0] == '"') {
 336                 /*
 337                  * Boundary string is a quoted-string
 338                  */
 339                 start++; /* Skip the quote */
 340                 len = index_of_char(start, '"');
 341                 if (len < 0) {
 342                         /*
 343                          * No closing quote
 344                          */
 345                         return NULL;
 346                 }
 347         } else {
 348                 /*
 349                  * Look for end of boundary
 350                  */
 351                 p = start;
 352                 while (*p) {
 353                         if (*p == ';' || isspace((guchar)*p))
 354                                 break;
 355                         p++;
 356                         len++;
 357                 }
 358         }
 359         /*
 360          * There is a value for the boundary string
 361          */
 362         m_info = g_malloc(sizeof(multipart_info_t));
 363         m_info->type = type;
 364         m_info->boundary = g_strndup(start, len);
 365         m_info->boundary_length = len;
 366
 367         return m_info;
 368 }
 369
 370 static void
 371 cleanup_multipart_info(void *data)
 372 {
 373         multipart_info_t *m_info = data;
 374         if (m_info) {
 375                 if (m_info->boundary)
 376                         g_free(m_info->boundary);
 377                 g_free(m_info);
 378         }
 379 }
 380
 381 /*
 382  * The first boundary does not implicitly contain the leading
 383  * line-end sequence.
 384  *
 385  * Return the offset to the 1st byte of the boundary delimiter line.
 386  * Set boundary_line_len to the length of the entire boundary delimiter.
 387  * Set last_boundary to TRUE if we've seen the last-boundary delimiter.
 388  */
 389 static gint
 390 find_first_boundary(tvbuff_t *tvb, gint start, const guint8 *boundary,
 391                 gint boundary_len, gint *boundary_line_len, gboolean *last_boundary)
 392 {
 393         gint offset = start, next_offset, line_len, boundary_start;
 394
 395         while (tvb_length_remaining(tvb, offset + 2 + boundary_len) > 0) {
 396                 boundary_start = offset;
 397                 if (((tvb_strneql(tvb, offset, (const guint8 *)"--", 2) == 0)
 398                                         && (tvb_strneql(tvb, offset + 2, boundary,      boundary_len) == 0)))
 399                 {
 400                         /* Boundary string; now check if last */
 401                         if ((tvb_length_remaining(tvb, offset + 2 + boundary_len + 2) >= 0)
 402                                         && (tvb_strneql(tvb, offset + 2 + boundary_len,
 403                                                         (const guint8 *)"--", 2) == 0)) {
 404                                 *last_boundary = TRUE;
 405                         } else {
 406                                 *last_boundary = FALSE;
 407                         }
 408                         /* Look for line end of the boundary line */
 409                         line_len =  tvb_find_line_end(tvb, offset, -1, &offset, FALSE);
 410                         if (line_len == -1) {
 411                                 *boundary_line_len = -1;
 412                         } else {
 413                                 *boundary_line_len = offset - boundary_start;
 414                         }
 415                         return boundary_start;
 416                 }
 417                 line_len =  tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 418                 if (line_len == -1) {
 419                         return -1;
 420                 }
 421                 offset = next_offset;
 422         }
 423
 424         return -1;
 425 }
 426
 427 /*
 428  * Unless the first boundary, subsequent boundaries include a line-end sequence
 429  * before the dashed boundary string.
 430  *
 431  * Return the offset to the 1st byte of the boundary delimiter line.
 432  * Set boundary_line_len to the length of the entire boundary delimiter.
 433  * Set last_boundary to TRUE if we've seen the last-boundary delimiter.
 434  */
 435 static gint
 436 find_next_boundary(tvbuff_t *tvb, gint start, const guint8 *boundary,
 437                 gint boundary_len, gint *boundary_line_len, gboolean *last_boundary)
 438 {
 439         gint offset = start, next_offset, line_len, boundary_start;
 440
 441         while (tvb_length_remaining(tvb, offset + 2 + boundary_len) > 0) {
 442                 line_len =  tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 443                 if (line_len == -1) {
 444                         return -1;
 445                 }
 446                 boundary_start = offset + line_len;
 447                 if (((tvb_strneql(tvb, next_offset, (const guint8 *)"--", 2) == 0)
 448                                         && (tvb_strneql(tvb, next_offset + 2, boundary, boundary_len) == 0)))
 449                 {
 450                         /* Boundary string; now check if last */
 451                         if ((tvb_length_remaining(tvb, next_offset + 2 + boundary_len + 2) >= 0)
 452                                         && (tvb_strneql(tvb, next_offset + 2 + boundary_len,
 453                                                         (const guint8 *)"--", 2) == 0)) {
 454                                 *last_boundary = TRUE;
 455                         } else {
 456                                 *last_boundary = FALSE;
 457                         }
 458                         /* Look for line end of the boundary line */
 459                         line_len =  tvb_find_line_end(tvb, next_offset, -1, &offset, FALSE);
 460                         if (line_len == -1) {
 461                                 *boundary_line_len = -1;
 462                         } else {
 463                                 *boundary_line_len = offset - boundary_start;
 464                         }
 465                         return boundary_start;
 466                 }
 467                 offset = next_offset;
 468         }
 469
 470         return -1;
 471 }
 472
 473 /*
 474  * Process the multipart preamble:
 475  *              [ preamble line-end ] dashed-boundary transport-padding line-end
 476  *
 477  * Return the offset to the start of the first body-part.
 478  */
 479 static gint
 480 process_preamble(proto_tree *tree, tvbuff_t *tvb, const guint8 *boundary,
 481                 gint boundary_len, gboolean *last_boundary)
 482 {
 483         gint boundary_start, boundary_line_len, body_part_start;
 484
 485         body_part_start = 0;
 486         boundary_start = find_first_boundary(tvb, 0, boundary, boundary_len,
 487                         &boundary_line_len, last_boundary);
 488         if (boundary_start == 0) {
 489                 if (tree) {
 490                         proto_tree_add_text(tree, tvb, boundary_start, boundary_line_len,
 491                                         "First boundary: %s",
 492                                         tvb_format_text(tvb, boundary_start, boundary_line_len));
 493                 }
 494                 return boundary_start + boundary_line_len;
 495         } else if (boundary_start > 0) {
 496                 if (boundary_line_len > 0) {
 497                         gint body_part_start = boundary_start + boundary_line_len;
 498
 499                         if (tree) {
 500                                 if (body_part_start > 0) {
 501                                         proto_tree_add_text(tree, tvb, 0, body_part_start,
 502                                                         "Preamble");
 503                                 }
 504                                 proto_tree_add_text(tree, tvb, boundary_start,
 505                                                 boundary_line_len, "First boundary: %s",
 506                                                 tvb_format_text(tvb, boundary_start,
 507                                                         boundary_line_len));
 508                         }
 509                         return body_part_start;
 510                 }
 511         }
 512         return -1;
 513 }
 514
 515 /*
 516  * Process a multipart body-part:
 517  *              MIME-part-headers [ line-end *OCTET ]
 518  *              line-end dashed-boundary transport-padding line-end
 519  *
 520  * If applicable, call a media subdissector.
 521  *
 522  * Return the offset to the start of the next body-part.
 523  */
 524 static gint
 525 process_body_part(proto_tree *tree, tvbuff_t *tvb, const guint8 *boundary,
 526                 gint boundary_len, packet_info *pinfo, gint start,
 527                 gboolean *last_boundary)
 528 {
 529         proto_tree *subtree = NULL;
 530         proto_item *ti = NULL;
 531         gint offset = start, next_offset;
 532         gint line_len = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 533         char *parameters = NULL;
 534         gint body_start, boundary_start, boundary_line_len;
 535
 536         char *content_type_str = NULL;
 537
 538         if (tree) {
 539                 ti = proto_tree_add_text(tree, tvb, start, 0,
 540                                 "Encapsulated multipart part");
 541                 subtree = proto_item_add_subtree(ti, ett_multipart_body);
 542         }
 543         /*
 544          * Process the MIME-part-headers
 545          */
 546
 547         while (line_len > 0)
 548         {
 549                 gint colon_offset;
 550                 char *header_str = tvb_get_string(tvb, offset, next_offset - offset);
 551
 552                 header_str = unfold_and_compact_mime_header(header_str, &colon_offset);
 553                 if (colon_offset <= 0) {
 554                         if (tree) {
 555                                 proto_tree_add_text(subtree, tvb, offset, next_offset - offset,
 556                                                 "%s",
 557                                                 tvb_format_text(tvb, offset, next_offset - offset));
 558                         }
 559                 } else {
 560                         gint hf_index;
 561
 562                         /* Split header name from header value */
 563                         header_str[colon_offset] = '\0';
 564                         hf_index = is_known_multipart_header(header_str, colon_offset);
 565
 566                         if (hf_index == -1) {
 567                                 if (tree) {
 568                                         proto_tree_add_text(subtree, tvb, offset,
 569                                                         next_offset - offset,
 570                                                         "%s",
 571                                                         tvb_format_text(tvb, offset, next_offset - offset));
 572                                 }
 573                         } else {
 574                                 char *value_str = header_str + colon_offset + 1;
 575
 576                                 if (tree) {
 577                                         proto_tree_add_string_format(subtree,
 578                                                         hf_header_array[hf_index], tvb,
 579                                                         offset, next_offset - offset,
 580                                                         (const char *)value_str, "%s",
 581                                                         tvb_format_text(tvb, offset, next_offset - offset));
 582                                 }
 583
 584                                 switch (hf_index) {
 585                                         case POS_CONTENT_TYPE:
 586                                                 {
 587                                                         /* The Content-Type starts at colon_offset + 1 */
 588                                                         gint semicolon_offset = index_of_char(
 589                                                                         value_str, ';');
 590
 591                                                         if (semicolon_offset > 0) {
 592                                                                 value_str[semicolon_offset] = '\0';
 593                                                                 parameters = value_str + semicolon_offset + 1;
 594                                                         } else {
 595                                                                 parameters = NULL;
 596                                                         }
 597 #if GLIB_MAJOR_VERSION < 2
 598                                                         content_type_str = g_strdup(value_str);
 599                                                         g_strdown(content_type_str);
 600 #else
 601                                                         content_type_str = g_ascii_strdown(value_str, -1);
 602 #endif
 603                                                 }
 604                                                 break;
 605
 606                                         default:
 607                                                 break;
 608                                 }
 609                         }
 610                 }
 611                 offset = next_offset;
 612                 line_len = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 613         }
 614         if (line_len < 0) {
 615                 /* ERROR */
 616                 return -1;
 617         }
 618         proto_tree_add_text(subtree, tvb, offset, next_offset - offset,
 619                         "%s", tvb_format_text(tvb, offset, next_offset - offset));
 620
 621         body_start = next_offset;
 622
 623         /*
 624          * Process the body
 625          */
 626
 627         boundary_start = find_next_boundary(tvb, body_start, boundary, boundary_len,
 628                         &boundary_line_len, last_boundary);
 629         if (boundary_start > 0) {
 630                 gint body_len = boundary_start - body_start;
 631                 tvbuff_t *tmp_tvb = tvb_new_subset(tvb, body_start,
 632                                 body_len, body_len);
 633
 634                 if (content_type_str) {
 635                         /*
 636                          * subdissection
 637                          */
 638                         void *save_private_data = pinfo->private_data;
 639                         gboolean dissected;
 640
 641                         pinfo->private_data = parameters;
 642                         /*
 643                          * First try the dedicated multipart dissector table
 644                          */
 645                         dissected = dissector_try_string(multipart_media_subdissector_table,
 646                                                 content_type_str, tmp_tvb, pinfo, subtree);
 647                         if (! dissected) {
 648                                 /*
 649                                  * Fall back to the default media dissector table
 650                                  */
 651                                 dissected = dissector_try_string(media_type_dissector_table,
 652                                                 content_type_str, tmp_tvb, pinfo, subtree);
 653                         }
 654                         pinfo->private_data = save_private_data;
 655                         g_free(content_type_str);
 656                         content_type_str = NULL;
 657                         parameters = NULL; /* Shares same memory as content_type_str */
 658                         if (! dissected) {
 659                                 call_dissector(data_handle, tmp_tvb, pinfo, subtree);
 660                         }
 661                 } else {
 662                         call_dissector(data_handle, tmp_tvb, pinfo, subtree);
 663                 }
 664                 if (tree) {
 665                         if (*last_boundary == TRUE) {
 666                                 proto_tree_add_text(tree, tvb,
 667                                                 boundary_start, boundary_line_len,
 668                                                 "Last boundary: %s",
 669                                                 tvb_format_text(tvb, boundary_start,
 670                                                         boundary_line_len));
 671                         } else {
 672                                 proto_tree_add_text(tree, tvb,
 673                                                 boundary_start, boundary_line_len,
 674                                                 "Boundary: %s",
 675                                                 tvb_format_text(tvb, boundary_start,
 676                                                         boundary_line_len));
 677                         }
 678                 }
 679                 return boundary_start + boundary_line_len;
 680         }
 681
 682         return -1;
 683 }
 684
 685 /*
 686  * Call this method to actually dissect the multipart body.
 687  * NOTE - Only do so if a boundary string has been found!
 688  */
 689 static void dissect_multipart(tvbuff_t *tvb, packet_info *pinfo,
 690                 proto_tree *tree)
 691 {
 692         proto_tree *subtree = NULL;
 693         proto_item *ti = NULL;
 694         multipart_info_t *m_info = get_multipart_info(pinfo);
 695         gint header_start = 0;
 696         guint8 *boundary;
 697         gint boundary_len;
 698         gint offset = 0;
 699         gboolean last_boundary = FALSE;
 700
 701         if (m_info == NULL) {
 702                 /*
 703                  * We can't get the required multipart information
 704                  */
 705                 proto_tree_add_text(tree, tvb, 0, -1,
 706                                 "The multipart dissector could not find "
 707                                 "the required boundary parameter.");
 708                 call_dissector(data_handle, tvb, pinfo, tree);
 709                 return;
 710         }
 711         boundary = (guint8 *)m_info->boundary;
 712         boundary_len = m_info->boundary_length;
 713         /* Clean up the memory if an exception is thrown */
 714         /* CLEANUP_PUSH(cleanup_multipart_info, m_info); */
 715
 716         /* Add stuff to the protocol tree */
 717         if (tree) {
 718                 ti = proto_tree_add_item(tree, proto_multipart,
 719                                 tvb, 0, -1, FALSE);
 720                 subtree = proto_item_add_subtree(ti, ett_multipart);
 721                 proto_item_append_text(ti, ", Type: %s, Boundary: \"%s\"",
 722                                 m_info->type, m_info->boundary);
 723                 proto_tree_add_string(subtree, hf_multipart_type,
 724                                 tvb, 0, 0, pinfo->match_string);
 725         }
 726
 727         /*
 728          * Make no entries in Protocol column and Info column on summary display,
 729          * but stop sub-dissectors from clearing entered text in summary display.
 730          */
 731         if (check_col(pinfo->cinfo, COL_INFO))
 732                 col_set_fence(pinfo->cinfo, COL_INFO);
 733
 734         offset = 0;
 735
 736         /*
 737          * Process the multipart preamble
 738          */
 739         header_start = process_preamble(subtree, tvb, boundary,
 740                         boundary_len, &last_boundary);
 741         if (header_start == -1) {
 742                 call_dissector(data_handle, tvb, pinfo, subtree);
 743                 /* Clean up the dynamically allocated memory */
 744                 cleanup_multipart_info(m_info);
 745                 return;
 746         }
 747         /*
 748          * Process the encapsulated bodies
 749          */
 750         while (last_boundary == FALSE) {
 751                 header_start = process_body_part(subtree, tvb, boundary, boundary_len,
 752                                 pinfo, header_start, &last_boundary);
 753                 if (header_start == -1) {
 754                         /* Clean up the dynamically allocated memory */
 755                         cleanup_multipart_info(m_info);
 756                         return;
 757                 }
 758         }
 759         /*
 760          * Process the multipart trailer
 761          */
 762         if (tree) {
 763                 if (tvb_length_remaining(tvb, header_start) > 0) {
 764                         proto_tree_add_text(subtree, tvb, header_start, -1, "Trailer");
 765                 }
 766         }
 767         /* Clean up the dynamically allocated memory */
 768         cleanup_multipart_info(m_info);
 769         return;
 770 }
 771
 772 /* Returns index of method in multipart_headers */
 773 static gint
 774 is_known_multipart_header(const char *header_str, guint len)
 775 {
 776         guint i;
 777
 778         for (i = 1; i < array_length(multipart_headers); i++) {
 779                 if (len == strlen(multipart_headers[i]) &&
 780                         strncasecmp(header_str, multipart_headers[i], len) == 0) {
 781                         return i;
 782                 }
 783         }
 784
 785         return -1;
 786 }
 787
 788 /*
 789  * Register the protocol with Ethereal.
 790  *
 791  * This format is required because a script is used to build the C function
 792  * that calls all the protocol registration.
 793  */
 794
 795 void
 796 proto_register_multipart(void)
 797 {
 798
 799 /* Setup list of header fields  See Section 1.6.1 for details */
 800         static hf_register_info hf[] = {
 801                 { &hf_multipart_type,
 802                         {       "Type",
 803                                 "mime_multipart.type",
 804                                 FT_STRING, BASE_NONE, NULL, 0x00,
 805                                 "RFC 3261: MIME multipart encapsulation type", HFILL
 806                         }
 807                 },
 808                 { &hf_header_array[POS_CONTENT_DISPOSITION],
 809                         {       "Content-Disposition",
 810                                 "mime_multipart.header.content-disposition",
 811                                 FT_STRING, BASE_NONE, NULL, 0x00,
 812                                 "RFC 3261: Content-Disposition Header", HFILL
 813                         }
 814                 },
 815                 { &hf_header_array[POS_CONTENT_ENCODING],
 816                         {       "Content-Encoding",
 817                                 "mime_multipart.header.content-encoding",
 818                                 FT_STRING, BASE_NONE, NULL, 0x00,
 819                                 "RFC 3261: Content-Encoding Header", HFILL
 820                         }
 821                 },
 822                 { &hf_header_array[POS_CONTENT_LANGUAGE],
 823                         {       "Content-Language",
 824                                 "mime_multipart.header.content-language",
 825                                 FT_STRING, BASE_NONE, NULL, 0x00,
 826                                 "RFC 3261: Content-Language Header", HFILL
 827                         }
 828                 },
 829                 { &hf_header_array[POS_CONTENT_LENGTH],
 830                         {       "Content-Length",
 831                                 "mime_multipart.header.content-length",
 832                                 FT_STRING, BASE_NONE, NULL, 0x0,
 833                                 "RFC 3261: Content-Length Header", HFILL
 834                         }
 835                 },
 836                 { &hf_header_array[POS_CONTENT_TYPE],
 837                         {       "Content-Type",
 838                                 "mime_multipart.header.content-type",
 839                                 FT_STRING, BASE_NONE,NULL,0x0,
 840                                 "RFC 3261: Content-Type Header", HFILL
 841                         }
 842                 },
 843         };
 844
 845         /*
 846          * Preferences
 847          */
 848         module_t *multipart_module;
 849
 850         /*
 851          * Setup protocol subtree array
 852          */
 853         static gint *ett[] = {
 854                 &ett_multipart,
 855                 &ett_multipart_main,
 856                 &ett_multipart_body,
 857         };
 858
 859         /*
 860          * Register the protocol name and description
 861          */
 862         proto_multipart = proto_register_protocol(
 863                         "MIME Multipart Media Encapsulation",
 864                         "MIME multipart",
 865                         "mime_multipart");
 866
 867         /*
 868          * Required function calls to register
 869          * the header fields and subtrees used.
 870          */
 871         proto_register_field_array(proto_multipart, hf, array_length(hf));
 872         proto_register_subtree_array(ett, array_length(ett));
 873
 874         /*
 875          * Get the content type and Internet media type table
 876          */
 877         media_type_dissector_table = find_dissector_table("media_type");
 878
 879         multipart_module = prefs_register_protocol(proto_multipart, NULL);
 880
 881         prefs_register_bool_preference(multipart_module,
 882                         "display_unknown_body_as_text",
 883                         "Display bodies without media type as text",
 884                         "Display multipart bodies with no media type dissector"
 885                         " as raw text (may cause problems with binary data).",
 886                         &display_unknown_body_as_text);
 887
 888         /*
 889          * Dissectors requiring different behavior in cases where the media
 890          * is contained in a multipart entity should register their multipart
 891          * dissector in the dissector table below, which is similar to the
 892          * "media_type" dissector table defined in the HTTP dissector code.
 893          */
 894         multipart_media_subdissector_table = register_dissector_table(
 895                         "multipart_media_type",
 896                         "Internet media type (for multipart processing)",
 897                         FT_STRING, BASE_NONE);
 898 }
 899
 900
 901 /* If this dissector uses sub-dissector registration add a registration routine.
 902    This format is required because a script is used to find these routines and
 903    create the code that calls these routines.
 904 */
 905 void
 906 proto_reg_handoff_multipart(void)
 907 {
 908         dissector_handle_t multipart_handle;
 909
 910         /*
 911          * When we cannot display the data, call the data dissector
 912          */
 913         data_handle = find_dissector("data");
 914
 915         /*
 916          * Handle for multipart dissection
 917          */
 918         multipart_handle = create_dissector_handle(
 919                         dissect_multipart, proto_multipart);
 920
 921         dissector_add_string("media_type",
 922                         "multipart/mixed", multipart_handle);
 923         dissector_add_string("media_type",
 924                         "multipart/related", multipart_handle);
 925         dissector_add_string("media_type",
 926                         "multipart/alternative", multipart_handle);
 927         dissector_add_string("media_type",
 928                         "multipart/form-data", multipart_handle);
 929
 930 }