citadel/mime_parser.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the MIME parser for Citadel.
   5  *
   6  * Copyright (c) 1998-2005 by Art Cancro
   7  * This code is distributed under the terms of the GNU General Public License.
   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 "citadel.h"
  22 #include "server.h"
  23 #include "serv_extensions.h"
  24 #include "sysdep_decls.h"
  25 #include "tools.h"
  26
  27 #include "mime_parser.h"
  28
  29
  30 void extract_key(char *target, char *source, char *key)
  31 {
  32         int a, b;
  33
  34         strcpy(target, source);
  35         for (a = 0; a < strlen(target); ++a) {
  36                 if ((!strncasecmp(&target[a], key, strlen(key)))
  37                     && (target[a + strlen(key)] == '=')) {
  38                         strcpy(target, &target[a + strlen(key) + 1]);
  39                         if (target[0] == 34)
  40                                 strcpy(target, &target[1]);
  41                         for (b = 0; b < strlen(target); ++b)
  42                                 if (target[b] == 34)
  43                                         target[b] = 0;
  44                         return;
  45                 }
  46         }
  47         strcpy(target, "");
  48 }
  49
  50
  51 /*
  52  * For non-multipart messages, we need to generate a quickie partnum of "1"
  53  * to return to callback functions.  Some callbacks demand it.
  54  */
  55 char *fixed_partnum(char *supplied_partnum) {
  56         if (supplied_partnum == NULL) return "1";
  57         if (strlen(supplied_partnum)==0) return "1";
  58         return supplied_partnum;
  59 }
  60
  61
  62
  63 /*
  64  * Convert "quoted-printable" to binary.  Returns number of bytes decoded.
  65  */
  66 int CtdlDecodeQuotedPrintable(char *decoded, char *encoded, int sourcelen) {
  67         char buf[SIZ];
  68         int buf_length = 0;
  69         int soft_line_break = 0;
  70         unsigned int ch;
  71         int decoded_length = 0;
  72         int i;
  73
  74         decoded[0] = 0;
  75         decoded_length = 0;
  76         buf[0] = 0;
  77         buf_length = 0;
  78
  79         for (i = 0; i < sourcelen; ++i) {
  80
  81                 buf[buf_length++] = encoded[i];
  82
  83                 if ( (encoded[i] == '\n')
  84                    || (encoded[i] == 0)
  85                    || (i == (sourcelen-1)) ) {
  86                         buf[buf_length++] = 0;
  87
  88                         /*** begin -- process one line ***/
  89
  90                         if (buf[strlen(buf)-1] == '\n') {
  91                                 buf[strlen(buf)-1] = 0;
  92                         }
  93                         if (buf[strlen(buf)-1] == '\r') {
  94                                 buf[strlen(buf)-1] = 0;
  95                         }
  96                         while (isspace(buf[strlen(buf)-1])) {
  97                                 buf[strlen(buf)-1] = 0;
  98                         }
  99                         soft_line_break = 0;
 100
 101                         while (strlen(buf) > 0) {
 102                                 if (!strcmp(buf, "=")) {
 103                                         soft_line_break = 1;
 104                                         strcpy(buf, "");
 105                                 } else if ((strlen(buf)>=3) && (buf[0]=='=')) {
 106                                         sscanf(&buf[1], "%02x", &ch);
 107                                         decoded[decoded_length++] = ch;
 108                                         strcpy(buf, &buf[3]);
 109                                 } else {
 110                                         decoded[decoded_length++] = buf[0];
 111                                         strcpy(buf, &buf[1]);
 112                                 }
 113                         }
 114                         if (soft_line_break == 0) {
 115                                 decoded[decoded_length++] = '\r';
 116                                 decoded[decoded_length++] = '\n';
 117                         }
 118                         buf_length = 0;
 119                         /*** end -- process one line ***/
 120                 }
 121         }
 122
 123         decoded[decoded_length++] = 0;
 124         return(decoded_length);
 125 }
 126
 127 /*
 128  * Given a message or message-part body and a length, handle any necessary
 129  * decoding and pass the request up the stack.
 130  */
 131 void mime_decode(char *partnum,
 132                  char *part_start, size_t length,
 133                  char *content_type, char *charset, char *encoding,
 134                  char *disposition,
 135                  char *name, char *filename,
 136                  void (*CallBack)
 137                   (char *cbname,
 138                    char *cbfilename,
 139                    char *cbpartnum,
 140                    char *cbdisp,
 141                    void *cbcontent,
 142                    char *cbtype,
 143                    char *cbcharset,
 144                    size_t cblength,
 145                    char *cbencoding,
 146                    void *cbuserdata),
 147                  void (*PreMultiPartCallBack)
 148                   (char *cbname,
 149                    char *cbfilename,
 150                    char *cbpartnum,
 151                    char *cbdisp,
 152                    void *cbcontent,
 153                    char *cbtype,
 154                    char *cbcharset,
 155                    size_t cblength,
 156                    char *cbencoding,
 157                    void *cbuserdata),
 158                  void (*PostMultiPartCallBack)
 159                   (char *cbname,
 160                    char *cbfilename,
 161                    char *cbpartnum,
 162                    char *cbdisp,
 163                    void *cbcontent,
 164                    char *cbtype,
 165                    char *cbcharset,
 166                    size_t cblength,
 167                    char *cbencoding,
 168                    void *cbuserdata),
 169                   void *userdata,
 170                   int dont_decode
 171 )
 172 {
 173
 174         char *decoded;
 175         size_t bytes_decoded = 0;
 176
 177         /* Some encodings aren't really encodings */
 178         if (!strcasecmp(encoding, "7bit"))
 179                 strcpy(encoding, "");
 180         if (!strcasecmp(encoding, "8bit"))
 181                 strcpy(encoding, "");
 182         if (!strcasecmp(encoding, "binary"))
 183                 strcpy(encoding, "");
 184
 185         /* If this part is not encoded, send as-is */
 186         if ( (strlen(encoding) == 0) || (dont_decode)) {
 187                 if (CallBack != NULL) {
 188                         CallBack(name, filename, fixed_partnum(partnum),
 189                                 disposition, part_start,
 190                                 content_type, charset, length, encoding, userdata);
 191                         }
 192                 return;
 193         }
 194
 195         if ((strcasecmp(encoding, "base64"))
 196             && (strcasecmp(encoding, "quoted-printable"))) {
 197                 return;
 198         }
 199         /*
 200          * Allocate a buffer for the decoded data.  The output buffer is the
 201          * same size as the input buffer; this assumes that the decoded data
 202          * will never be larger than the encoded data.  This is a safe
 203          * assumption with base64, uuencode, and quoted-printable.
 204          */
 205         decoded = malloc(length+2048);
 206         if (decoded == NULL) {
 207                 return;
 208         }
 209
 210         if (!strcasecmp(encoding, "base64")) {
 211                 bytes_decoded = CtdlDecodeBase64(decoded, part_start, length);
 212         }
 213         else if (!strcasecmp(encoding, "quoted-printable")) {
 214                 bytes_decoded = CtdlDecodeQuotedPrintable(decoded,
 215                                                         part_start, length);
 216         }
 217
 218         if (bytes_decoded > 0) if (CallBack != NULL) {
 219                 CallBack(name, filename, fixed_partnum(partnum),
 220                         disposition, decoded,
 221                         content_type, charset, bytes_decoded, "binary", userdata);
 222         }
 223
 224         free(decoded);
 225 }
 226
 227 /*
 228  * Break out the components of a multipart message
 229  * (This function expects to be fed HEADERS + CONTENT)
 230  * Note: NULL can be supplied as content_end; in this case, the message is
 231  * considered to have ended when the parser encounters a 0x00 byte.
 232  */
 233 void the_mime_parser(char *partnum,
 234                      char *content_start, char *content_end,
 235                      void (*CallBack)
 236                       (char *cbname,
 237                        char *cbfilename,
 238                        char *cbpartnum,
 239                        char *cbdisp,
 240                        void *cbcontent,
 241                        char *cbtype,
 242                        char *cbcharset,
 243                        size_t cblength,
 244                        char *cbencoding,
 245                        void *cbuserdata),
 246                      void (*PreMultiPartCallBack)
 247                       (char *cbname,
 248                        char *cbfilename,
 249                        char *cbpartnum,
 250                        char *cbdisp,
 251                        void *cbcontent,
 252                        char *cbtype,
 253                        char *cbcharset,
 254                        size_t cblength,
 255                        char *cbencoding,
 256                        void *cbuserdata),
 257                      void (*PostMultiPartCallBack)
 258                       (char *cbname,
 259                        char *cbfilename,
 260                        char *cbpartnum,
 261                        char *cbdisp,
 262                        void *cbcontent,
 263                        char *cbtype,
 264                        char *cbcharset,
 265                        size_t cblength,
 266                        char *cbencoding,
 267                        void *cbuserdata),
 268                       void *userdata,
 269                       int dont_decode
 270 )
 271 {
 272
 273         char *ptr;
 274         char *srch = NULL;
 275         char *part_start, *part_end = NULL;
 276         char buf[SIZ];
 277         char *header;
 278         char *boundary;
 279         char *startary;
 280         size_t startary_len = 0;
 281         char *endary;
 282         char *next_boundary;
 283         char *content_type;
 284         char *charset;
 285         size_t content_length;
 286         char *encoding;
 287         char *disposition;
 288         char *name = NULL;
 289         char *content_type_name;
 290         char *content_disposition_name;
 291         char *filename;
 292         int is_multipart;
 293         int part_seq = 0;
 294         int i;
 295         size_t length;
 296         char nested_partnum[SIZ];
 297
 298         ptr = content_start;
 299         content_length = 0;
 300
 301         boundary = malloc(SIZ);
 302         memset(boundary, 0, SIZ);
 303
 304         startary = malloc(SIZ);
 305         memset(startary, 0, SIZ);
 306
 307         endary = malloc(SIZ);
 308         memset(endary, 0, SIZ);
 309
 310         header = malloc(SIZ);
 311         memset(header, 0, SIZ);
 312
 313         content_type = malloc(SIZ);
 314         memset(content_type, 0, SIZ);
 315
 316         charset = malloc(SIZ);
 317         memset(charset, 0, SIZ);
 318
 319         encoding = malloc(SIZ);
 320         memset(encoding, 0, SIZ);
 321
 322         content_type_name = malloc(SIZ);
 323         memset(content_type_name, 0, SIZ);
 324
 325         content_disposition_name = malloc(SIZ);
 326         memset(content_disposition_name, 0, SIZ);
 327
 328         filename = malloc(SIZ);
 329         memset(filename, 0, SIZ);
 330
 331         disposition = malloc(SIZ);
 332         memset(disposition, 0, SIZ);
 333
 334         /* If the caller didn't supply an endpointer, generate one by measure */
 335         if (content_end == NULL) {
 336                 content_end = &content_start[strlen(content_start)];
 337         }
 338
 339         /* Learn interesting things from the headers */
 340         strcpy(header, "");
 341         do {
 342                 ptr = memreadline(ptr, buf, SIZ);
 343                 if (ptr >= content_end) {
 344                         goto end_parser;
 345                 }
 346
 347                 for (i = 0; i < strlen(buf); ++i) {
 348                         if (isspace(buf[i])) {
 349                                 buf[i] = ' ';
 350                         }
 351                 }
 352
 353                 if (!isspace(buf[0])) {
 354                         if (!strncasecmp(header, "Content-type: ", 14)) {
 355                                 strcpy(content_type, &header[14]);
 356                                 extract_key(content_type_name, content_type, "name");
 357                                 extract_key(charset, content_type, "charset");
 358                                 /* Deal with weird headers */
 359                                 if (strchr(content_type, ' '))
 360                                         *(strchr(content_type, ' ')) = '\0';
 361                                 if (strchr(content_type, ';'))
 362                                         *(strchr(content_type, ';')) = '\0';
 363                         }
 364                         if (!strncasecmp(header, "Content-Disposition: ", 21)) {
 365                                 strcpy(disposition, &header[21]);
 366                                 extract_key(content_disposition_name, disposition, "name");
 367                                 extract_key(filename, disposition, "filename");
 368                         }
 369                         if (!strncasecmp(header, "Content-length: ", 16)) {
 370                                 content_length = (size_t) atol(&header[16]);
 371                         }
 372                         if (!strncasecmp(header,
 373                                       "Content-transfer-encoding: ", 27))
 374                                 strcpy(encoding, &header[27]);
 375                         if (strlen(boundary) == 0)
 376                                 extract_key(boundary, header, "boundary");
 377                         strcpy(header, "");
 378                 }
 379                 if ((strlen(header) + strlen(buf) + 2) < SIZ)
 380                         strcat(header, buf);
 381         } while ((strlen(buf) > 0) && (*ptr != 0));
 382
 383         if (strchr(disposition, ';'))
 384                 *(strchr(disposition, ';')) = '\0';
 385         striplt(disposition);
 386         if (strchr(content_type, ';'))
 387                 *(strchr(content_type, ';')) = '\0';
 388         striplt(content_type);
 389
 390         if (strlen(boundary) > 0) {
 391                 is_multipart = 1;
 392         } else {
 393                 is_multipart = 0;
 394         }
 395
 396         /* If this is a multipart message, then recursively process it */
 397         part_start = NULL;
 398         if (is_multipart) {
 399
 400                 /* Tell the client about this message's multipartedness */
 401                 if (PreMultiPartCallBack != NULL) {
 402                         PreMultiPartCallBack("", "", partnum, "",
 403                                 NULL, content_type, charset,
 404                                 0, encoding, userdata);
 405                 }
 406
 407                 /* Figure out where the boundaries are */
 408                 snprintf(startary, SIZ, "--%s", boundary);
 409                 snprintf(endary, SIZ, "--%s--", boundary);
 410                 startary_len = strlen(startary);
 411
 412                 part_start = NULL;
 413                 do {
 414                         next_boundary = NULL;
 415                         for (srch=ptr; srch<content_end; ++srch) {
 416                                 if (!memcmp(srch, startary, startary_len)) {
 417                                         next_boundary = srch;
 418                                         srch = content_end;
 419                                 }
 420                         }
 421
 422                         if ( (part_start != NULL) && (next_boundary != NULL) ) {
 423                                 part_end = next_boundary;
 424                                 --part_end;
 425
 426                                 if (strlen(partnum) > 0) {
 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                                         ++part_start;
 456                                         ptr = part_start;
 457                                 }
 458                         }
 459                         else {
 460                                 /* Invalid end of multipart.  Bail out! */
 461                                 ptr = content_end;
 462                         }
 463                 } while ( (ptr < content_end) && (next_boundary != NULL) );
 464
 465                 if (PostMultiPartCallBack != NULL) {
 466                         PostMultiPartCallBack("", "", partnum, "", NULL,
 467                                 content_type, charset, 0, encoding, userdata);
 468                 }
 469                 goto end_parser;
 470         }
 471
 472         /* If it's not a multipart message, then do something with it */
 473         if (!is_multipart) {
 474                 part_start = ptr;
 475                 length = 0;
 476                 while (ptr < content_end) {
 477                         ++ptr;
 478                         ++length;
 479                 }
 480                 part_end = content_end;
 481                 /* fix an off-by-one error */
 482                 --part_end;
 483                 --length;
 484
 485                 /* Truncate if the header told us to */
 486                 if ( (content_length > 0) && (length > content_length) ) {
 487                         length = content_length;
 488                 }
 489
 490                 /* Sometimes the "name" field is tacked on to Content-type,
 491                  * and sometimes it's tacked on to Content-disposition.  Use
 492                  * whichever one we have.
 493                  */
 494                 if (strlen(content_disposition_name) > strlen(content_type_name)) {
 495                         name = content_disposition_name;
 496                 }
 497                 else {
 498                         name = content_type_name;
 499                 }
 500
 501                 /* lprintf(CTDL_DEBUG, "mime_decode part=%s, len=%d, type=%s, charset=%s, encoding=%s\n",
 502                         partnum, length, content_type, charset, encoding); */
 503
 504                 /* Ok, we've got a non-multipart part here, so do something with it.
 505                  */
 506                 mime_decode(partnum,
 507                         part_start, length,
 508                         content_type, charset, encoding, disposition,
 509                         name, filename,
 510                         CallBack, NULL, NULL,
 511                         userdata, dont_decode
 512                 );
 513         }
 514
 515 end_parser:     /* free the buffers!  end the oppression!! */
 516         free(boundary);
 517         free(startary);
 518         free(endary);
 519         free(header);
 520         free(content_type);
 521         free(charset);
 522         free(encoding);
 523         free(content_type_name);
 524         free(content_disposition_name);
 525         free(filename);
 526         free(disposition);
 527 }
 528
 529
 530
 531 /*
 532  * Entry point for the MIME parser.
 533  * (This function expects to be fed HEADERS + CONTENT)
 534  * Note: NULL can be supplied as content_end; in this case, the message is
 535  * considered to have ended when the parser encounters a 0x00 byte.
 536  */
 537 void mime_parser(char *content_start,
 538                 char *content_end,
 539
 540                  void (*CallBack)
 541                   (char *cbname,
 542                    char *cbfilename,
 543                    char *cbpartnum,
 544                    char *cbdisp,
 545                    void *cbcontent,
 546                    char *cbtype,
 547                    char *cbcharset,
 548                    size_t cblength,
 549                    char *cbencoding,
 550                    void *cbuserdata),
 551
 552                  void (*PreMultiPartCallBack)
 553                   (char *cbname,
 554                    char *cbfilename,
 555                    char *cbpartnum,
 556                    char *cbdisp,
 557                    void *cbcontent,
 558                    char *cbtype,
 559                    char *cbcharset,
 560                    size_t cblength,
 561                    char *cbencoding,
 562                    void *cbuserdata),
 563
 564                  void (*PostMultiPartCallBack)
 565                   (char *cbname,
 566                    char *cbfilename,
 567                    char *cbpartnum,
 568                    char *cbdisp,
 569                    void *cbcontent,
 570                    char *cbtype,
 571                    char *cbcharset,
 572                    size_t cblength,
 573                    char *cbencoding,
 574                    void *cbuserdata),
 575
 576                   void *userdata,
 577                   int dont_decode
 578 )
 579 {
 580
 581         the_mime_parser("", content_start, content_end,
 582                         CallBack,
 583                         PreMultiPartCallBack,
 584                         PostMultiPartCallBack,
 585                         userdata, dont_decode);
 586 }