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