citadel/mime_parser.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the MIME parser for Citadel.  Sometimes it actually works.
   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 #ifdef DLL_EXPORT
  12 #define IN_LIBCIT
  13 #endif
  14
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17 #include <stdio.h>
  18 #include <signal.h>
  19 #include <sys/types.h>
  20 #include <ctype.h>
  21 #include <string.h>
  22 #include <sys/stat.h>
  23 #include <errno.h>
  24
  25 #include "citadel.h"
  26 #include "server.h"
  27 #include "serv_extensions.h"
  28 #include "sysdep_decls.h"
  29 #include "tools.h"
  30
  31 #include "mime_parser.h"
  32
  33
  34 void extract_key(char *target, char *source, char *key)
  35 {
  36         int a, b;
  37
  38         strcpy(target, source);
  39         for (a = 0; a < strlen(target); ++a) {
  40                 if ((!strncasecmp(&target[a], key, strlen(key)))
  41                     && (target[a + strlen(key)] == '=')) {
  42                         strcpy(target, &target[a + strlen(key) + 1]);
  43                         if (target[0] == 34)
  44                                 strcpy(target, &target[1]);
  45                         for (b = 0; b < strlen(target); ++b)
  46                                 if (target[b] == 34)
  47                                         target[b] = 0;
  48                         return;
  49                 }
  50         }
  51         strcpy(target, "");
  52 }
  53
  54
  55 /*
  56  * For non-multipart messages, we need to generate a quickie partnum of "1"
  57  * to return to callback functions.  Some callbacks demand it.
  58  */
  59 char *fixed_partnum(char *supplied_partnum) {
  60         if (supplied_partnum == NULL) return "1";
  61         if (strlen(supplied_partnum)==0) return "1";
  62         return supplied_partnum;
  63 }
  64
  65
  66
  67 /*
  68  * Convert "quoted-printable" to binary.  Returns number of bytes decoded.
  69  */
  70 int CtdlDecodeQuotedPrintable(char *decoded, char *encoded, int sourcelen) {
  71         char buf[SIZ];
  72         int buf_length = 0;
  73         int soft_line_break = 0;
  74         unsigned int ch;
  75         int decoded_length = 0;
  76         int i;
  77
  78         decoded[0] = 0;
  79         decoded_length = 0;
  80         buf[0] = 0;
  81         buf_length = 0;
  82
  83         for (i = 0; i < sourcelen; ++i) {
  84
  85                 buf[buf_length++] = encoded[i];
  86
  87                 if ( (encoded[i] == '\n')
  88                    || (encoded[i] == 0)
  89                    || (i == (sourcelen-1)) ) {
  90                         buf[buf_length++] = 0;
  91
  92                         /*** begin -- process one line ***/
  93
  94                         if (buf[strlen(buf)-1] == '\n') {
  95                                 buf[strlen(buf)-1] = 0;
  96                         }
  97                         if (buf[strlen(buf)-1] == '\r') {
  98                                 buf[strlen(buf)-1] = 0;
  99                         }
 100                         while (isspace(buf[strlen(buf)-1])) {
 101                                 buf[strlen(buf)-1] = 0;
 102                         }
 103                         soft_line_break = 0;
 104
 105                         while (strlen(buf) > 0) {
 106                                 if (!strcmp(buf, "=")) {
 107                                         soft_line_break = 1;
 108                                         strcpy(buf, "");
 109                                 } else if ((strlen(buf)>=3) && (buf[0]=='=')) {
 110                                         sscanf(&buf[1], "%02x", &ch);
 111                                         decoded[decoded_length++] = ch;
 112                                         strcpy(buf, &buf[3]);
 113                                 } else {
 114                                         decoded[decoded_length++] = buf[0];
 115                                         strcpy(buf, &buf[1]);
 116                                 }
 117                         }
 118                         if (soft_line_break == 0) {
 119                                 decoded[decoded_length++] = '\r';
 120                                 decoded[decoded_length++] = '\n';
 121                         }
 122                         buf_length = 0;
 123                         /*** end -- process one line ***/
 124                 }
 125         }
 126
 127         decoded[decoded_length++] = 0;
 128         return(decoded_length);
 129 }
 130
 131 /*
 132  * Given a message or message-part body and a length, handle any necessary
 133  * decoding and pass the request up the stack.
 134  */
 135 void mime_decode(char *partnum,
 136                  char *part_start, size_t length,
 137                  char *content_type, char *charset, char *encoding,
 138                  char *disposition,
 139                  char *name, char *filename,
 140                  void (*CallBack)
 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 (*PreMultiPartCallBack)
 152                   (char *cbname,
 153                    char *cbfilename,
 154                    char *cbpartnum,
 155                    char *cbdisp,
 156                    void *cbcontent,
 157                    char *cbtype,
 158                    char *cbcharset,
 159                    size_t cblength,
 160                    char *cbencoding,
 161                    void *cbuserdata),
 162                  void (*PostMultiPartCallBack)
 163                   (char *cbname,
 164                    char *cbfilename,
 165                    char *cbpartnum,
 166                    char *cbdisp,
 167                    void *cbcontent,
 168                    char *cbtype,
 169                    char *cbcharset,
 170                    size_t cblength,
 171                    char *cbencoding,
 172                    void *cbuserdata),
 173                   void *userdata,
 174                   int dont_decode
 175 )
 176 {
 177
 178         char *decoded;
 179         size_t bytes_decoded = 0;
 180
 181         /* Some encodings aren't really encodings */
 182         if (!strcasecmp(encoding, "7bit"))
 183                 strcpy(encoding, "");
 184         if (!strcasecmp(encoding, "8bit"))
 185                 strcpy(encoding, "");
 186         if (!strcasecmp(encoding, "binary"))
 187                 strcpy(encoding, "");
 188
 189         /* If this part is not encoded, send as-is */
 190         if ( (strlen(encoding) == 0) || (dont_decode)) {
 191                 if (CallBack != NULL) {
 192                         CallBack(name, filename, fixed_partnum(partnum),
 193                                 disposition, part_start,
 194                                 content_type, charset, length, encoding, userdata);
 195                         }
 196                 return;
 197         }
 198
 199         if ((strcasecmp(encoding, "base64"))
 200             && (strcasecmp(encoding, "quoted-printable"))) {
 201                 return;
 202         }
 203         /*
 204          * Allocate a buffer for the decoded data.  The output buffer is the
 205          * same size as the input buffer; this assumes that the decoded data
 206          * will never be larger than the encoded data.  This is a safe
 207          * assumption with base64, uuencode, and quoted-printable.
 208          */
 209         decoded = malloc(length+2048);
 210         if (decoded == NULL) {
 211                 return;
 212         }
 213
 214         if (!strcasecmp(encoding, "base64")) {
 215                 bytes_decoded = CtdlDecodeBase64(decoded, part_start, length);
 216         }
 217         else if (!strcasecmp(encoding, "quoted-printable")) {
 218                 bytes_decoded = CtdlDecodeQuotedPrintable(decoded,
 219                                                         part_start, length);
 220         }
 221
 222         if (bytes_decoded > 0) if (CallBack != NULL) {
 223                 CallBack(name, filename, fixed_partnum(partnum),
 224                         disposition, decoded,
 225                         content_type, charset, bytes_decoded, "binary", userdata);
 226         }
 227
 228         free(decoded);
 229 }
 230
 231 /*
 232  * Break out the components of a multipart message
 233  * (This function expects to be fed HEADERS + CONTENT)
 234  * Note: NULL can be supplied as content_end; in this case, the message is
 235  * considered to have ended when the parser encounters a 0x00 byte.
 236  */
 237 void the_mime_parser(char *partnum,
 238                      char *content_start, char *content_end,
 239                      void (*CallBack)
 240                       (char *cbname,
 241                        char *cbfilename,
 242                        char *cbpartnum,
 243                        char *cbdisp,
 244                        void *cbcontent,
 245                        char *cbtype,
 246                        char *cbcharset,
 247                        size_t cblength,
 248                        char *cbencoding,
 249                        void *cbuserdata),
 250                      void (*PreMultiPartCallBack)
 251                       (char *cbname,
 252                        char *cbfilename,
 253                        char *cbpartnum,
 254                        char *cbdisp,
 255                        void *cbcontent,
 256                        char *cbtype,
 257                        char *cbcharset,
 258                        size_t cblength,
 259                        char *cbencoding,
 260                        void *cbuserdata),
 261                      void (*PostMultiPartCallBack)
 262                       (char *cbname,
 263                        char *cbfilename,
 264                        char *cbpartnum,
 265                        char *cbdisp,
 266                        void *cbcontent,
 267                        char *cbtype,
 268                        char *cbcharset,
 269                        size_t cblength,
 270                        char *cbencoding,
 271                        void *cbuserdata),
 272                       void *userdata,
 273                       int dont_decode
 274 )
 275 {
 276
 277         char *ptr;
 278         char *part_start, *part_end = NULL;
 279         char buf[SIZ];
 280         char *header;
 281         char *boundary;
 282         char *startary;
 283         char *endary;
 284         char *next_boundary;
 285         char *content_type;
 286         char *charset;
 287         size_t content_length;
 288         char *encoding;
 289         char *disposition;
 290         char *name = NULL;
 291         char *content_type_name;
 292         char *content_disposition_name;
 293         char *filename;
 294         int is_multipart;
 295         int part_seq = 0;
 296         int i;
 297         size_t length;
 298         char nested_partnum[SIZ];
 299
 300         ptr = content_start;
 301         content_length = 0;
 302
 303         boundary = malloc(SIZ);
 304         memset(boundary, 0, SIZ);
 305
 306         startary = malloc(SIZ);
 307         memset(startary, 0, SIZ);
 308
 309         endary = malloc(SIZ);
 310         memset(endary, 0, SIZ);
 311
 312         header = malloc(SIZ);
 313         memset(header, 0, SIZ);
 314
 315         content_type = malloc(SIZ);
 316         memset(content_type, 0, SIZ);
 317
 318         charset = malloc(SIZ);
 319         memset(charset, 0, SIZ);
 320
 321         encoding = malloc(SIZ);
 322         memset(encoding, 0, SIZ);
 323
 324         content_type_name = malloc(SIZ);
 325         memset(content_type_name, 0, SIZ);
 326
 327         content_disposition_name = malloc(SIZ);
 328         memset(content_disposition_name, 0, SIZ);
 329
 330         filename = malloc(SIZ);
 331         memset(filename, 0, SIZ);
 332
 333         disposition = malloc(SIZ);
 334         memset(disposition, 0, SIZ);
 335
 336         /* If the caller didn't supply an endpointer, generate one by measure */
 337         if (content_end == NULL) {
 338                 content_end = &content_start[strlen(content_start)];
 339         }
 340
 341         /* Learn interesting things from the headers */
 342         strcpy(header, "");
 343         do {
 344                 ptr = memreadline(ptr, buf, SIZ);
 345                 if (ptr >= content_end) {
 346                         goto end_parser;
 347                 }
 348
 349                 for (i = 0; i < strlen(buf); ++i) {
 350                         if (isspace(buf[i])) {
 351                                 buf[i] = ' ';
 352                         }
 353                 }
 354
 355                 if (!isspace(buf[0])) {
 356                         if (!strncasecmp(header, "Content-type: ", 14)) {
 357                                 strcpy(content_type, &header[14]);
 358                                 extract_key(content_type_name, content_type, "name");
 359                                 extract_key(charset, content_type, "charset");
 360                                 /* Deal with weird headers */
 361                                 if (strchr(content_type, ' '))
 362                                         *(strchr(content_type, ' ')) = '\0';
 363                                 if (strchr(content_type, ';'))
 364                                         *(strchr(content_type, ';')) = '\0';
 365                         }
 366                         if (!strncasecmp(header, "Content-Disposition: ", 21)) {
 367                                 strcpy(disposition, &header[21]);
 368                                 extract_key(content_disposition_name, disposition, "name");
 369                                 extract_key(filename, disposition, "filename");
 370                         }
 371                         if (!strncasecmp(header, "Content-length: ", 16)) {
 372                                 content_length = (size_t) atol(&header[16]);
 373                         }
 374                         if (!strncasecmp(header,
 375                                       "Content-transfer-encoding: ", 27))
 376                                 strcpy(encoding, &header[27]);
 377                         if (strlen(boundary) == 0)
 378                                 extract_key(boundary, header, "boundary");
 379                         strcpy(header, "");
 380                 }
 381                 if ((strlen(header) + strlen(buf) + 2) < SIZ)
 382                         strcat(header, buf);
 383         } while ((strlen(buf) > 0) && (*ptr != 0));
 384
 385         if (strchr(disposition, ';'))
 386                 *(strchr(disposition, ';')) = '\0';
 387         striplt(disposition);
 388         if (strchr(content_type, ';'))
 389                 *(strchr(content_type, ';')) = '\0';
 390         striplt(content_type);
 391
 392         if (!strlen(content_type)) {
 393                 strcpy(content_type, "text/plain");
 394         }
 395         if (!strlen(charset)) {
 396                 strcpy(charset, "us-ascii");
 397         }
 398
 399         if (strlen(boundary) > 0) {
 400                 is_multipart = 1;
 401         } else {
 402                 is_multipart = 0;
 403         }
 404
 405         /* If this is a multipart message, then recursively process it */
 406         part_start = NULL;
 407         if (is_multipart) {
 408
 409                 /* Tell the client about this message's multipartedness */
 410                 if (PreMultiPartCallBack != NULL) {
 411                         PreMultiPartCallBack("", "", partnum, "",
 412                                 NULL, content_type, charset,
 413                                 0, encoding, userdata);
 414                 }
 415
 416                 /* Figure out where the boundaries are */
 417                 snprintf(startary, SIZ, "--%s", boundary);
 418                 snprintf(endary, SIZ, "--%s--", boundary);
 419
 420                 part_start = NULL;
 421                 do {
 422                         next_boundary = bmstrstr(ptr, startary, strncmp);
 423                         if ( (part_start != NULL) && (next_boundary != NULL) ) {
 424                                 part_end = next_boundary;
 425                                 --part_end;
 426
 427                                 if (strlen(partnum) > 0) {
 428                                         snprintf(nested_partnum,
 429                                                  sizeof nested_partnum,
 430                                                  "%s.%d", partnum,
 431                                                  ++part_seq);
 432                                 }
 433                                 else {
 434                                         snprintf(nested_partnum,
 435                                                  sizeof nested_partnum,
 436                                                  "%d", ++part_seq);
 437                                 }
 438                                 the_mime_parser(nested_partnum,
 439                                             part_start, part_end,
 440                                                 CallBack,
 441                                                 PreMultiPartCallBack,
 442                                                 PostMultiPartCallBack,
 443                                                 userdata,
 444                                                 dont_decode);
 445                         }
 446
 447                         if (next_boundary != NULL) {
 448                                 /* If we pass out of scope, don't attempt to read
 449                                  * past the end boundary. */
 450                                 if (!strcmp(next_boundary, endary)) {
 451                                         ptr = content_end;
 452                                 }
 453                                 else {
 454                                         /* Set up for the next part. */
 455                                         part_start = strstr(next_boundary, "\n");
 456                                         ++part_start;
 457                                         ptr = part_start;
 458                                 }
 459                         }
 460                         else {
 461                                 /* Invalid end of multipart.  Bail out! */
 462                                 ptr = content_end;
 463                         }
 464                 } while ( (ptr < content_end) && (next_boundary != NULL) );
 465
 466                 if (PostMultiPartCallBack != NULL) {
 467                         PostMultiPartCallBack("", "", partnum, "", NULL,
 468                                 content_type, charset, 0, encoding, userdata);
 469                 }
 470                 goto end_parser;
 471         }
 472
 473         /* If it's not a multipart message, then do something with it */
 474         if (!is_multipart) {
 475                 part_start = ptr;
 476                 length = 0;
 477                 while (ptr < content_end) {
 478                         ++ptr;
 479                         ++length;
 480                 }
 481                 part_end = content_end;
 482                 /* fix an off-by-one error */
 483                 --part_end;
 484                 --length;
 485
 486                 /* Truncate if the header told us to */
 487                 if ( (content_length > 0) && (length > content_length) ) {
 488                         length = content_length;
 489                 }
 490
 491                 /* Sometimes the "name" field is tacked on to Content-type,
 492                  * and sometimes it's tacked on to Content-disposition.  Use
 493                  * whichever one we have.
 494                  */
 495                 if (strlen(content_disposition_name) > strlen(content_type_name)) {
 496                         name = content_disposition_name;
 497                 }
 498                 else {
 499                         name = content_type_name;
 500                 }
 501
 502                 mime_decode(partnum,
 503                             part_start, length,
 504                             content_type, charset, encoding, disposition,
 505                             name, filename,
 506                             CallBack, NULL, NULL,
 507                             userdata, dont_decode);
 508         }
 509
 510 end_parser:     /* free the buffers!  end the oppression!! */
 511         free(boundary);
 512         free(startary);
 513         free(endary);
 514         free(header);
 515         free(content_type);
 516         free(charset);
 517         free(encoding);
 518         free(content_type_name);
 519         free(content_disposition_name);
 520         free(filename);
 521         free(disposition);
 522 }
 523
 524
 525
 526 /*
 527  * Entry point for the MIME parser.
 528  * (This function expects to be fed HEADERS + CONTENT)
 529  * Note: NULL can be supplied as content_end; in this case, the message is
 530  * considered to have ended when the parser encounters a 0x00 byte.
 531  */
 532 void mime_parser(char *content_start,
 533                 char *content_end,
 534
 535                  void (*CallBack)
 536                   (char *cbname,
 537                    char *cbfilename,
 538                    char *cbpartnum,
 539                    char *cbdisp,
 540                    void *cbcontent,
 541                    char *cbtype,
 542                    char *cbcharset,
 543                    size_t cblength,
 544                    char *cbencoding,
 545                    void *cbuserdata),
 546
 547                  void (*PreMultiPartCallBack)
 548                   (char *cbname,
 549                    char *cbfilename,
 550                    char *cbpartnum,
 551                    char *cbdisp,
 552                    void *cbcontent,
 553                    char *cbtype,
 554                    char *cbcharset,
 555                    size_t cblength,
 556                    char *cbencoding,
 557                    void *cbuserdata),
 558
 559                  void (*PostMultiPartCallBack)
 560                   (char *cbname,
 561                    char *cbfilename,
 562                    char *cbpartnum,
 563                    char *cbdisp,
 564                    void *cbcontent,
 565                    char *cbtype,
 566                    char *cbcharset,
 567                    size_t cblength,
 568                    char *cbencoding,
 569                    void *cbuserdata),
 570
 571                   void *userdata,
 572                   int dont_decode
 573 )
 574 {
 575
 576         the_mime_parser("", content_start, content_end,
 577                         CallBack,
 578                         PreMultiPartCallBack,
 579                         PostMultiPartCallBack,
 580                         userdata, dont_decode);
 581 }