libcitadel/lib/mime_parser.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the MIME parser for Citadel.
   5  *
   6  * Copyright (c) 1998-2007 by the citadel.org development team.
   7  * This code is distributed under the GNU General Public License v3.
   8  *
   9  */
  10
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <stdio.h>
  14 #include <signal.h>
  15 #include <sys/types.h>
  16 #include <ctype.h>
  17 #include <string.h>
  18 #include <sys/stat.h>
  19 #include <errno.h>
  20
  21 #include "xdgmime/xdgmime.h"
  22 #include "libcitadel.h"
  23
  24 void extract_key(char *target, char *source, char *key)
  25 {
  26         char *ptr;
  27         char looking_for[256];
  28         int double_quotes = 0;
  29
  30         snprintf(looking_for, sizeof looking_for, "%s=", key);
  31
  32         ptr = bmstrcasestr(source, looking_for);
  33         if (ptr == NULL) {
  34                 strcpy(target, "");
  35                 return;
  36         }
  37         strcpy(target, (ptr + strlen(looking_for)));
  38
  39         for (ptr=target; (*ptr != 0); ++ptr) {
  40
  41                 /* A semicolon means we've hit the end of the key, unless we're inside double quotes */
  42                 if ( (double_quotes != 1) && (*ptr == ';')) {
  43                         *ptr = 0;
  44                 }
  45
  46                 /* if we find double quotes, we've got a great set of string boundaries */
  47                 if (*ptr == '\"') {
  48                         ++double_quotes;
  49                         if (double_quotes == 1) {
  50                                 strcpy(ptr, ptr+1);
  51                         }
  52                         else {
  53                                 *ptr = 0;
  54                         }
  55                 }
  56         }
  57 }
  58
  59
  60 /*
  61  * For non-multipart messages, we need to generate a quickie partnum of "1"
  62  * to return to callback functions.  Some callbacks demand it.
  63  */
  64 char *fixed_partnum(char *supplied_partnum) {
  65         if (supplied_partnum == NULL) return "1";
  66         if (strlen(supplied_partnum)==0) return "1";
  67         return supplied_partnum;
  68 }
  69
  70
  71
  72 /*
  73  * Convert "quoted-printable" to binary.  Returns number of bytes decoded.
  74  * according to RFC2045 section 6.7
  75  */
  76 int CtdlDecodeQuotedPrintable(char *decoded, char *encoded, int sourcelen) {
  77         unsigned int ch;
  78         int decoded_length = 0;
  79         int pos = 0;
  80
  81         while (pos < sourcelen)
  82         {
  83                 if (!strncmp(&encoded[pos], "=\r\n", 3))
  84                 {
  85                         pos += 3;
  86                 }
  87                 else if (!strncmp(&encoded[pos], "=\n", 2))
  88                 {
  89                         pos += 2;
  90                 }
  91                 else if (encoded[pos] == '=')
  92                 {
  93                         ch = 0;
  94                         sscanf(&encoded[pos+1], "%02x", &ch);
  95                         pos += 3;
  96                         decoded[decoded_length++] = ch;
  97                 }
  98                 else
  99                 {
 100                         decoded[decoded_length++] = encoded[pos];
 101                         pos += 1;
 102                 }
 103         }
 104         decoded[decoded_length] = 0;
 105         return(decoded_length);
 106 }
 107
 108
 109 /*
 110  * Given a message or message-part body and a length, handle any necessary
 111  * decoding and pass the request up the stack.
 112  */
 113 void mime_decode(char *partnum,
 114                  char *part_start, size_t length,
 115                  char *content_type, char *charset, char *encoding,
 116                  char *disposition,
 117                  char *name, char *filename,
 118                  void (*CallBack)
 119                   (char *cbname,
 120                    char *cbfilename,
 121                    char *cbpartnum,
 122                    char *cbdisp,
 123                    void *cbcontent,
 124                    char *cbtype,
 125                    char *cbcharset,
 126                    size_t cblength,
 127                    char *cbencoding,
 128                    void *cbuserdata),
 129                  void (*PreMultiPartCallBack)
 130                   (char *cbname,
 131                    char *cbfilename,
 132                    char *cbpartnum,
 133                    char *cbdisp,
 134                    void *cbcontent,
 135                    char *cbtype,
 136                    char *cbcharset,
 137                    size_t cblength,
 138                    char *cbencoding,
 139                    void *cbuserdata),
 140                  void (*PostMultiPartCallBack)
 141                   (char *cbname,
 142                    char *cbfilename,
 143                    char *cbpartnum,
 144                    char *cbdisp,
 145                    void *cbcontent,
 146                    char *cbtype,
 147                    char *cbcharset,
 148                    size_t cblength,
 149                    char *cbencoding,
 150                    void *cbuserdata),
 151                   void *userdata,
 152                   int dont_decode
 153 )
 154 {
 155
 156         char *decoded;
 157         size_t bytes_decoded = 0;
 158
 159         /* Some encodings aren't really encodings */
 160         if (!strcasecmp(encoding, "7bit"))
 161                 strcpy(encoding, "");
 162         if (!strcasecmp(encoding, "8bit"))
 163                 strcpy(encoding, "");
 164         if (!strcasecmp(encoding, "binary"))
 165                 strcpy(encoding, "");
 166
 167         /* If this part is not encoded, send as-is */
 168         if ( (strlen(encoding) == 0) || (dont_decode)) {
 169                 if (CallBack != NULL) {
 170                         CallBack(name, filename, fixed_partnum(partnum),
 171                                 disposition, part_start,
 172                                 content_type, charset, length, encoding, userdata);
 173                         }
 174                 return;
 175         }
 176
 177         /* Fail silently if we hit an unknown encoding. */
 178         if ((strcasecmp(encoding, "base64"))
 179             && (strcasecmp(encoding, "quoted-printable"))) {
 180                 return;
 181         }
 182
 183         /*
 184          * Allocate a buffer for the decoded data.  The output buffer is slightly
 185          * larger than the input buffer; this assumes that the decoded data
 186          * will never be significantly larger than the encoded data.  This is a
 187          * safe assumption with base64, uuencode, and quoted-printable.
 188          */
 189         decoded = malloc(length + 32768);
 190         if (decoded == NULL) {
 191                 return;
 192         }
 193
 194         if (!strcasecmp(encoding, "base64")) {
 195                 bytes_decoded = CtdlDecodeBase64(decoded, part_start, length);
 196         }
 197         else if (!strcasecmp(encoding, "quoted-printable")) {
 198                 bytes_decoded = CtdlDecodeQuotedPrintable(decoded, part_start, length);
 199         }
 200
 201         if (bytes_decoded > 0) if (CallBack != NULL) {
 202                 CallBack(name, filename, fixed_partnum(partnum),
 203                         disposition, decoded,
 204                         content_type, charset, bytes_decoded, "binary", userdata);
 205         }
 206
 207         free(decoded);
 208 }
 209
 210 /*
 211  * Break out the components of a multipart message
 212  * (This function expects to be fed HEADERS + CONTENT)
 213  * Note: NULL can be supplied as content_end; in this case, the message is
 214  * considered to have ended when the parser encounters a 0x00 byte.
 215  */
 216 void the_mime_parser(char *partnum,
 217                      char *content_start, char *content_end,
 218                      void (*CallBack)
 219                       (char *cbname,
 220                        char *cbfilename,
 221                        char *cbpartnum,
 222                        char *cbdisp,
 223                        void *cbcontent,
 224                        char *cbtype,
 225                        char *cbcharset,
 226                        size_t cblength,
 227                        char *cbencoding,
 228                        void *cbuserdata),
 229                      void (*PreMultiPartCallBack)
 230                       (char *cbname,
 231                        char *cbfilename,
 232                        char *cbpartnum,
 233                        char *cbdisp,
 234                        void *cbcontent,
 235                        char *cbtype,
 236                        char *cbcharset,
 237                        size_t cblength,
 238                        char *cbencoding,
 239                        void *cbuserdata),
 240                      void (*PostMultiPartCallBack)
 241                       (char *cbname,
 242                        char *cbfilename,
 243                        char *cbpartnum,
 244                        char *cbdisp,
 245                        void *cbcontent,
 246                        char *cbtype,
 247                        char *cbcharset,
 248                        size_t cblength,
 249                        char *cbencoding,
 250                        void *cbuserdata),
 251                       void *userdata,
 252                       int dont_decode
 253 )
 254 {
 255
 256         char *ptr;
 257         char *srch = NULL;
 258         char *part_start, *part_end = NULL;
 259         char buf[SIZ];
 260         char *header;
 261         char *boundary;
 262         char *startary;
 263         size_t startary_len = 0;
 264         char *endary;
 265         char *next_boundary;
 266         char *content_type;
 267         char *charset;
 268         size_t content_length;
 269         char *encoding;
 270         char *disposition;
 271         char *name = NULL;
 272         char *content_type_name;
 273         char *content_disposition_name;
 274         char *filename;
 275         int is_multipart;
 276         int part_seq = 0;
 277         int i;
 278         size_t length;
 279         char nested_partnum[256];
 280         int crlf_in_use = 0;
 281         char *evaluate_crlf_ptr = NULL;
 282         int buflen = 0;
 283         int headerlen = 0;
 284
 285         ptr = content_start;
 286         content_length = 0;
 287
 288         boundary = malloc(SIZ);
 289         memset(boundary, 0, SIZ);
 290
 291         startary = malloc(SIZ);
 292         memset(startary, 0, SIZ);
 293
 294         endary = malloc(SIZ);
 295         memset(endary, 0, SIZ);
 296
 297         header = malloc(SIZ);
 298         memset(header, 0, SIZ);
 299
 300         content_type = malloc(SIZ);
 301         memset(content_type, 0, SIZ);
 302
 303         charset = malloc(SIZ);
 304         memset(charset, 0, SIZ);
 305
 306         encoding = malloc(SIZ);
 307         memset(encoding, 0, SIZ);
 308
 309         content_type_name = malloc(SIZ);
 310         memset(content_type_name, 0, SIZ);
 311
 312         content_disposition_name = malloc(SIZ);
 313         memset(content_disposition_name, 0, SIZ);
 314
 315         filename = malloc(SIZ);
 316         memset(filename, 0, SIZ);
 317
 318         disposition = malloc(SIZ);
 319         memset(disposition, 0, SIZ);
 320
 321         /* If the caller didn't supply an endpointer, generate one by measure */
 322         if (content_end == NULL) {
 323                 content_end = &content_start[strlen(content_start)];
 324         }
 325
 326         /* Learn interesting things from the headers */
 327         strcpy(header, "");
 328         headerlen = 0;
 329         do {
 330                 ptr = memreadlinelen(ptr, buf, SIZ, &buflen);
 331                 if (ptr >= content_end) {
 332                         goto end_parser;
 333                 }
 334
 335                 for (i = 0; i < buflen; ++i) {
 336                         if (isspace(buf[i])) {
 337                                 buf[i] = ' ';
 338                         }
 339                 }
 340
 341                 if (!isspace(buf[0])) {
 342                         if (!strncasecmp(header, "Content-type:", 13)) {
 343                                 strcpy(content_type, &header[13]);
 344                                 striplt(content_type);
 345                                 extract_key(content_type_name, content_type, "name");
 346                                 extract_key(charset, content_type, "charset");
 347                                 extract_key(boundary, header, "boundary");
 348                                 /* Deal with weird headers */
 349                                 if (strchr(content_type, ' '))
 350                                         *(strchr(content_type, ' ')) = '\0';
 351                                 if (strchr(content_type, ';'))
 352                                         *(strchr(content_type, ';')) = '\0';
 353                         }
 354                         if (!strncasecmp(header, "Content-Disposition:", 20)) {
 355                                 strcpy(disposition, &header[20]);
 356                                 striplt(disposition);
 357                                 extract_key(content_disposition_name, disposition, "name");
 358                                 extract_key(filename, disposition, "filename");
 359                         }
 360                         if (!strncasecmp(header, "Content-length: ", 15)) {
 361                                 char clbuf[10];
 362                                 safestrncpy(clbuf, &header[15], sizeof clbuf);
 363                                 striplt(clbuf);
 364                                 content_length = (size_t) atol(clbuf);
 365                         }
 366                         if (!strncasecmp(header, "Content-transfer-encoding: ", 26)) {
 367                                 strcpy(encoding, &header[26]);
 368                                 striplt(encoding);
 369                         }
 370                         strcpy(header, "");
 371                         headerlen = 0;
 372                 }
 373                 if ((headerlen + buflen + 2) < SIZ) {
 374                         memcpy(&header[headerlen], buf, buflen);
 375                         headerlen += buflen;
 376                         header[headerlen] = '\0';
 377                 }
 378         } while ((!IsEmptyStr(buf)) && (*ptr != 0));
 379
 380         if (strchr(disposition, ';'))
 381                 *(strchr(disposition, ';')) = '\0';
 382         striplt(disposition);
 383         if (strchr(content_type, ';'))
 384                 *(strchr(content_type, ';')) = '\0';
 385         striplt(content_type);
 386
 387         if (!IsEmptyStr(boundary)) {
 388                 is_multipart = 1;
 389         } else {
 390                 is_multipart = 0;
 391         }
 392
 393         /* If this is a multipart message, then recursively process it */
 394         part_start = NULL;
 395         if (is_multipart) {
 396
 397                 /* Tell the client about this message's multipartedness */
 398                 if (PreMultiPartCallBack != NULL) {
 399                         PreMultiPartCallBack("", "", partnum, "",
 400                                 NULL, content_type, charset,
 401                                 0, encoding, userdata);
 402                 }
 403
 404                 /* Figure out where the boundaries are */
 405                 snprintf(startary, SIZ, "--%s", boundary);
 406                 snprintf(endary, SIZ, "--%s--", boundary);
 407                 startary_len = strlen(startary);
 408
 409                 part_start = NULL;
 410                 do {
 411                         next_boundary = NULL;
 412                         for (srch=ptr; srch<content_end; ++srch) {
 413                                 if (!memcmp(srch, startary, startary_len)) {
 414                                         next_boundary = srch;
 415                                         srch = content_end;
 416                                 }
 417                         }
 418
 419                         if ( (part_start != NULL) && (next_boundary != NULL) ) {
 420                                 part_end = next_boundary;
 421                                 --part_end;             /* omit the trailing LF */
 422                                 if (crlf_in_use) {
 423                                         --part_end;     /* omit the trailing CR */
 424                                 }
 425
 426                                 if (!IsEmptyStr(partnum)) {
 427                                         snprintf(nested_partnum,
 428                                                  sizeof nested_partnum,
 429                                                  "%s.%d", partnum,
 430                                                  ++part_seq);
 431                                 }
 432                                 else {
 433                                         snprintf(nested_partnum,
 434                                                  sizeof nested_partnum,
 435                                                  "%d", ++part_seq);
 436                                 }
 437                                 the_mime_parser(nested_partnum,
 438                                             part_start, part_end,
 439                                                 CallBack,
 440                                                 PreMultiPartCallBack,
 441                                                 PostMultiPartCallBack,
 442                                                 userdata,
 443                                                 dont_decode);
 444                         }
 445
 446                         if (next_boundary != NULL) {
 447                                 /* If we pass out of scope, don't attempt to
 448                                  * read past the end boundary. */
 449                                 if (!strcmp(next_boundary, endary)) {
 450                                         ptr = content_end;
 451                                 }
 452                                 else {
 453                                         /* Set up for the next part. */
 454                                         part_start = strstr(next_boundary, "\n");
 455
 456                                         /* Determine whether newlines are LF or CRLF */
 457                                         evaluate_crlf_ptr = part_start;
 458                                         --evaluate_crlf_ptr;
 459                                         if (!memcmp(evaluate_crlf_ptr, "\r\n", 2)) {
 460                                                 crlf_in_use = 1;
 461                                         }
 462                                         else {
 463                                                 crlf_in_use = 0;
 464                                         }
 465
 466                                         /* Advance past the LF ... now we're in the next part */
 467                                         ++part_start;
 468                                         ptr = part_start;
 469                                 }
 470                         }
 471                         else {
 472                                 /* Invalid end of multipart.  Bail out! */
 473                                 ptr = content_end;
 474                         }
 475                 } while ( (ptr < content_end) && (next_boundary != NULL) );
 476
 477                 if (PostMultiPartCallBack != NULL) {
 478                         PostMultiPartCallBack("", "", partnum, "", NULL,
 479                                 content_type, charset, 0, encoding, userdata);
 480                 }
 481                 goto end_parser;
 482         }
 483
 484         /* If it's not a multipart message, then do something with it */
 485         if (!is_multipart) {
 486                 part_start = ptr;
 487                 length = 0;
 488                 while (ptr < content_end) {
 489                         ++ptr;
 490                         ++length;
 491                 }
 492                 part_end = content_end;
 493
 494                 /******
 495                  * I thought there was an off-by-one error here, but there isn't.
 496                  * This probably means that there's an off-by-one error somewhere
 497                  * else ... or maybe only in certain messages?
 498                 --part_end;
 499                 --length;
 500                 ******/
 501
 502                 /* Truncate if the header told us to */
 503                 if ( (content_length > 0) && (length > content_length) ) {
 504                         length = content_length;
 505                 }
 506
 507                 /* Sometimes the "name" field is tacked on to Content-type,
 508                  * and sometimes it's tacked on to Content-disposition.  Use
 509                  * whichever one we have.
 510                  */
 511                 if (strlen(content_disposition_name) > strlen(content_type_name)) {
 512                         name = content_disposition_name;
 513                 }
 514                 else {
 515                         name = content_type_name;
 516                 }
 517
 518                 /* Ok, we've got a non-multipart part here, so do something with it.
 519                  */
 520                 mime_decode(partnum,
 521                         part_start, length,
 522                         content_type, charset, encoding, disposition,
 523                         name, filename,
 524                         CallBack, NULL, NULL,
 525                         userdata, dont_decode
 526                 );
 527
 528                 /*
 529                  * Now if it's an encapsulated message/rfc822 then we have to recurse into it
 530                  */
 531                 if (!strcasecmp(content_type, "message/rfc822")) {
 532
 533                         if (PreMultiPartCallBack != NULL) {
 534                                 PreMultiPartCallBack("", "", partnum, "",
 535                                         NULL, content_type, charset,
 536                                         0, encoding, userdata);
 537                         }
 538                         if (CallBack != NULL) {
 539                                 if (strlen(partnum) > 0) {
 540                                         snprintf(nested_partnum,
 541                                                  sizeof nested_partnum,
 542                                                  "%s.%d", partnum,
 543                                                  ++part_seq);
 544                                 }
 545                                 else {
 546                                         snprintf(nested_partnum,
 547                                                  sizeof nested_partnum,
 548                                                  "%d", ++part_seq);
 549                                 }
 550                                 the_mime_parser(nested_partnum,
 551                                         part_start, part_end,
 552                                         CallBack,
 553                                         PreMultiPartCallBack,
 554                                         PostMultiPartCallBack,
 555                                         userdata,
 556                                         dont_decode
 557                                 );
 558                         }
 559                         if (PostMultiPartCallBack != NULL) {
 560                                 PostMultiPartCallBack("", "", partnum, "", NULL,
 561                                         content_type, charset, 0, encoding, userdata);
 562                         }
 563
 564
 565                 }
 566
 567         }
 568
 569 end_parser:     /* free the buffers!  end the oppression!! */
 570         free(boundary);
 571         free(startary);
 572         free(endary);
 573         free(header);
 574         free(content_type);
 575         free(charset);
 576         free(encoding);
 577         free(content_type_name);
 578         free(content_disposition_name);
 579         free(filename);
 580         free(disposition);
 581 }
 582
 583
 584
 585 /*
 586  * Entry point for the MIME parser.
 587  * (This function expects to be fed HEADERS + CONTENT)
 588  * Note: NULL can be supplied as content_end; in this case, the message is
 589  * considered to have ended when the parser encounters a 0x00 byte.
 590  */
 591 void mime_parser(char *content_start,
 592                 char *content_end,
 593
 594                  void (*CallBack)
 595                   (char *cbname,
 596                    char *cbfilename,
 597                    char *cbpartnum,
 598                    char *cbdisp,
 599                    void *cbcontent,
 600                    char *cbtype,
 601                    char *cbcharset,
 602                    size_t cblength,
 603                    char *cbencoding,
 604                    void *cbuserdata),
 605
 606                  void (*PreMultiPartCallBack)
 607                   (char *cbname,
 608                    char *cbfilename,
 609                    char *cbpartnum,
 610                    char *cbdisp,
 611                    void *cbcontent,
 612                    char *cbtype,
 613                    char *cbcharset,
 614                    size_t cblength,
 615                    char *cbencoding,
 616                    void *cbuserdata),
 617
 618                  void (*PostMultiPartCallBack)
 619                   (char *cbname,
 620                    char *cbfilename,
 621                    char *cbpartnum,
 622                    char *cbdisp,
 623                    void *cbcontent,
 624                    char *cbtype,
 625                    char *cbcharset,
 626                    size_t cblength,
 627                    char *cbencoding,
 628                    void *cbuserdata),
 629
 630                   void *userdata,
 631                   int dont_decode
 632 )
 633 {
 634
 635         the_mime_parser("", content_start, content_end,
 636                         CallBack,
 637                         PreMultiPartCallBack,
 638                         PostMultiPartCallBack,
 639                         userdata, dont_decode);
 640 }
 641
 642
 643
 644
 645
 646
 647 typedef struct _MimeGuess {
 648         const char *Pattern;
 649         size_t PatternLen;
 650         long PatternOffset;
 651         const char *MimeString;
 652 } MimeGuess;
 653
 654 MimeGuess MyMimes [] = {
 655         {
 656                 "GIF",
 657                 3,
 658                 0,
 659                 "image/gif"
 660         },
 661         {
 662                 "\xff\xd8",
 663                 2,
 664                 0,
 665                 "image/jpeg"
 666         },
 667         {
 668                 "\x89PNG",
 669                 4,
 670                 0,
 671                 "image/png"
 672         },
 673         { // last...
 674                 "",
 675                 0,
 676                 0,
 677                 ""
 678         }
 679 };
 680
 681
 682 const char *GuessMimeType(char *data, size_t dlen)
 683 {
 684         return (xdg_mime_get_mime_type_for_data(data, dlen));
 685 /*
 686         int MimeIndex = 0;
 687
 688         while (MyMimes[MimeIndex].PatternLen != 0)
 689         {
 690                 if ((MyMimes[MimeIndex].PatternLen +
 691                      MyMimes[MimeIndex].PatternOffset < dlen) &&
 692                     strncmp(MyMimes[MimeIndex].Pattern,
 693                             &data[MyMimes[MimeIndex].PatternOffset],
 694                             MyMimes[MimeIndex].PatternLen) == 0)
 695                 {
 696                         break;
 697                 }
 698                 MimeIndex ++;
 699         }
 700         return MyMimes[MimeIndex].MimeString;
 701 */
 702 }
 703
 704
 705 const char* GuessMimeByFilename(const char *what, size_t len)
 706 {
 707         return xdg_mime_get_mime_type_from_file_name(what);
 708 /*
 709         if (!strncasecmp(&what[len - 4], ".gif", 4))
 710                 return "image/gif";
 711         else if (!strncasecmp(&what[len - 3], ".js", 3))
 712                 return  "text/javascript";
 713         else if (!strncasecmp(&what[len - 4], ".txt", 4))
 714                 return "text/plain";
 715         else if (!strncasecmp(&what[len - 4], ".css", 4))
 716                 return "text/css";
 717         else if (!strncasecmp(&what[len - 4], ".jpg", 4))
 718                 return "image/jpeg";
 719         else if (!strncasecmp(&what[len - 4], ".png", 4))
 720                 return "image/png";
 721         else if (!strncasecmp(&what[len - 4], ".ico", 4))
 722                 return "image/x-icon";
 723         else if (!strncasecmp(&what[len - 5], ".html", 5))
 724                 return "text/html";
 725         else if (!strncasecmp(&what[len - 4], ".htm", 4))
 726                 return "text/html";
 727         else if (!strncasecmp(&what[len - 4], ".wml", 4))
 728                 return "text/vnd.wap.wml";
 729         else if (!strncasecmp(&what[len - 5], ".wmls", 5))
 730                 return "text/vnd.wap.wmlscript";
 731         else if (!strncasecmp(&what[len - 5], ".wmlc", 5))
 732                 return "application/vnd.wap.wmlc";
 733         else if (!strncasecmp(&what[len - 6], ".wmlsc", 6))
 734                 return "application/vnd.wap.wmlscriptc";
 735         else if (!strncasecmp(&what[len - 5], ".wbmp", 5))
 736                 return "image/vnd.wap.wbmp";
 737         else
 738                 return "application/octet-stream";
 739 */
 740 }