citadel/mime_parser.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the MIME parser for Citadel.  Sometimes it actually works.
   5  *
   6  * Copyright (c) 1998-2002 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         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 *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                    size_t cblength,
 148                    char *cbencoding,
 149                    void *cbuserdata),
 150                  void (*PreMultiPartCallBack)
 151                   (char *cbname,
 152                    char *cbfilename,
 153                    char *cbpartnum,
 154                    char *cbdisp,
 155                    void *cbcontent,
 156                    char *cbtype,
 157                    size_t cblength,
 158                    char *cbencoding,
 159                    void *cbuserdata),
 160                  void (*PostMultiPartCallBack)
 161                   (char *cbname,
 162                    char *cbfilename,
 163                    char *cbpartnum,
 164                    char *cbdisp,
 165                    void *cbcontent,
 166                    char *cbtype,
 167                    size_t cblength,
 168                    char *cbencoding,
 169                    void *cbuserdata),
 170                   void *userdata,
 171                   int dont_decode
 172 )
 173 {
 174
 175         char *decoded;
 176         size_t bytes_decoded = 0;
 177
 178         /* Some encodings aren't really encodings */
 179         if (!strcasecmp(encoding, "7bit"))
 180                 strcpy(encoding, "");
 181         if (!strcasecmp(encoding, "8bit"))
 182                 strcpy(encoding, "");
 183         if (!strcasecmp(encoding, "binary"))
 184                 strcpy(encoding, "");
 185
 186         /* If this part is not encoded, send as-is */
 187         if ( (strlen(encoding) == 0) || (dont_decode)) {
 188                 if (CallBack != NULL) {
 189                         CallBack(name, filename, fixed_partnum(partnum),
 190                                 disposition, part_start,
 191                                 content_type, length, encoding, userdata);
 192                         }
 193                 return;
 194         }
 195
 196         if ((strcasecmp(encoding, "base64"))
 197             && (strcasecmp(encoding, "quoted-printable"))) {
 198                 return;
 199         }
 200         /*
 201          * Allocate a buffer for the decoded data.  The output buffer is the
 202          * same size as the input buffer; this assumes that the decoded data
 203          * will never be larger than the encoded data.  This is a safe
 204          * assumption with base64, uuencode, and quoted-printable.
 205          */
 206         decoded = malloc(length+2048);
 207         if (decoded == NULL) {
 208                 return;
 209         }
 210
 211         if (!strcasecmp(encoding, "base64")) {
 212                 bytes_decoded = CtdlDecodeBase64(decoded, part_start, length);
 213         }
 214         else if (!strcasecmp(encoding, "quoted-printable")) {
 215                 bytes_decoded = CtdlDecodeQuotedPrintable(decoded,
 216                                                         part_start, length);
 217         }
 218
 219         if (bytes_decoded > 0) if (CallBack != NULL) {
 220                 CallBack(name, filename, fixed_partnum(partnum),
 221                         disposition, decoded,
 222                         content_type, bytes_decoded, "binary", userdata);
 223         }
 224
 225         free(decoded);
 226 }
 227
 228 /*
 229  * Break out the components of a multipart message
 230  * (This function expects to be fed HEADERS + CONTENT)
 231  * Note: NULL can be supplied as content_end; in this case, the message is
 232  * considered to have ended when the parser encounters a 0x00 byte.
 233  */
 234 void the_mime_parser(char *partnum,
 235                      char *content_start, char *content_end,
 236                      void (*CallBack)
 237                       (char *cbname,
 238                        char *cbfilename,
 239                        char *cbpartnum,
 240                        char *cbdisp,
 241                        void *cbcontent,
 242                        char *cbtype,
 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                        size_t cblength,
 254                        char *cbencoding,
 255                        void *cbuserdata),
 256                      void (*PostMultiPartCallBack)
 257                       (char *cbname,
 258                        char *cbfilename,
 259                        char *cbpartnum,
 260                        char *cbdisp,
 261                        void *cbcontent,
 262                        char *cbtype,
 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 *part_start, *part_end = NULL;
 273         char buf[SIZ];
 274         char *header;
 275         char *boundary;
 276         char *startary;
 277         char *endary;
 278         char *next_boundary;
 279         char *content_type;
 280         size_t content_length;
 281         char *encoding;
 282         char *disposition;
 283         char *name = NULL;
 284         char *content_type_name;
 285         char *content_disposition_name;
 286         char *filename;
 287         int is_multipart;
 288         int part_seq = 0;
 289         int i;
 290         size_t length;
 291         char nested_partnum[SIZ];
 292
 293         ptr = content_start;
 294         content_length = 0;
 295
 296         boundary = malloc(SIZ);
 297         memset(boundary, 0, SIZ);
 298
 299         startary = malloc(SIZ);
 300         memset(startary, 0, SIZ);
 301
 302         endary = malloc(SIZ);
 303         memset(endary, 0, SIZ);
 304
 305         header = malloc(SIZ);
 306         memset(header, 0, SIZ);
 307
 308         content_type = malloc(SIZ);
 309         memset(content_type, 0, SIZ);
 310
 311         encoding = malloc(SIZ);
 312         memset(encoding, 0, SIZ);
 313
 314         content_type_name = malloc(SIZ);
 315         memset(content_type_name, 0, SIZ);
 316
 317         content_disposition_name = malloc(SIZ);
 318         memset(content_disposition_name, 0, SIZ);
 319
 320         filename = malloc(SIZ);
 321         memset(filename, 0, SIZ);
 322
 323         disposition = malloc(SIZ);
 324         memset(disposition, 0, SIZ);
 325
 326         /* If the caller didn't supply an endpointer, generate one by measure */
 327         if (content_end == NULL) {
 328                 content_end = &content_start[strlen(content_start)];
 329         }
 330
 331         /* Learn interesting things from the headers */
 332         strcpy(header, "");
 333         do {
 334                 ptr = memreadline(ptr, buf, SIZ);
 335                 if (ptr >= content_end) {
 336                         goto end_parser;
 337                 }
 338
 339                 for (i = 0; i < strlen(buf); ++i)
 340                         if (isspace(buf[i]))
 341                                 buf[i] = ' ';
 342                 if (!isspace(buf[0])) {
 343                         if (!strncasecmp(header, "Content-type: ", 14)) {
 344                                 strcpy(content_type, &header[14]);
 345                                 extract_key(content_type_name, content_type, "name");
 346                                 /* Deal with weird headers */
 347                                 if (strchr(content_type, ' '))
 348                                         *(strchr(content_type, ' ')) = '\0';
 349                                 if (strchr(content_type, ';'))
 350                                         *(strchr(content_type, ';')) = '\0';
 351                         }
 352                         if (!strncasecmp(header, "Content-Disposition: ", 21)) {
 353                                 strcpy(disposition, &header[21]);
 354                                 extract_key(content_disposition_name, disposition, "name");
 355                                 extract_key(filename, disposition, "filename");
 356                         }
 357                         if (!strncasecmp(header, "Content-length: ", 16)) {
 358                                 content_length = (size_t) atol(&header[16]);
 359                         }
 360                         if (!strncasecmp(header,
 361                                       "Content-transfer-encoding: ", 27))
 362                                 strcpy(encoding, &header[27]);
 363                         if (strlen(boundary) == 0)
 364                                 extract_key(boundary, header, "boundary");
 365                         strcpy(header, "");
 366                 }
 367                 if ((strlen(header) + strlen(buf) + 2) < SIZ)
 368                         strcat(header, buf);
 369         } while ((strlen(buf) > 0) && (*ptr != 0));
 370
 371         if (strchr(disposition, ';'))
 372                 *(strchr(disposition, ';')) = '\0';
 373         striplt(disposition);
 374         if (strchr(content_type, ';'))
 375                 *(strchr(content_type, ';')) = '\0';
 376         striplt(content_type);
 377
 378         if (strlen(boundary) > 0) {
 379                 is_multipart = 1;
 380         } else {
 381                 is_multipart = 0;
 382         }
 383
 384         /* If this is a multipart message, then recursively process it */
 385         part_start = NULL;
 386         if (is_multipart) {
 387
 388                 /* Tell the client about this message's multipartedness */
 389                 if (PreMultiPartCallBack != NULL) {
 390                         PreMultiPartCallBack("", "", partnum, "",
 391                                 NULL, content_type,
 392                                 0, encoding, userdata);
 393                 }
 394
 395                 /* Figure out where the boundaries are */
 396                 snprintf(startary, SIZ, "--%s", boundary);
 397                 snprintf(endary, SIZ, "--%s--", boundary);
 398
 399                 part_start = NULL;
 400                 do {
 401                         next_boundary = bmstrstr(ptr, startary, strncmp);
 402                         if ( (part_start != NULL) && (next_boundary != NULL) ) {
 403                                 part_end = next_boundary;
 404                                 --part_end;
 405
 406                                 if (strlen(partnum) > 0) {
 407                                         snprintf(nested_partnum,
 408                                                  sizeof nested_partnum,
 409                                                  "%s.%d", partnum,
 410                                                  ++part_seq);
 411                                 }
 412                                 else {
 413                                         snprintf(nested_partnum,
 414                                                  sizeof nested_partnum,
 415                                                  "%d", ++part_seq);
 416                                 }
 417                                 the_mime_parser(nested_partnum,
 418                                             part_start, part_end,
 419                                                 CallBack,
 420                                                 PreMultiPartCallBack,
 421                                                 PostMultiPartCallBack,
 422                                                 userdata,
 423                                                 dont_decode);
 424                         }
 425
 426                         if (next_boundary != NULL) {
 427                                 /* If we pass out of scope, don't attempt to read
 428                                  * past the end boundary. */
 429                                 if (!strcmp(next_boundary, endary)) {
 430                                         ptr = content_end;
 431                                 }
 432                                 else {
 433                                         /* Set up for the next part. */
 434                                         part_start = strstr(next_boundary, "\n");
 435                                         ++part_start;
 436                                         ptr = part_start;
 437                                 }
 438                         }
 439                         else {
 440                                 /* Invalid end of multipart.  Bail out! */
 441                                 ptr = content_end;
 442                         }
 443                 } while ( (ptr < content_end) && (next_boundary != NULL) );
 444
 445                 if (PostMultiPartCallBack != NULL) {
 446                         PostMultiPartCallBack("", "", partnum, "", NULL,
 447                                 content_type, 0, encoding, userdata);
 448                 }
 449                 goto end_parser;
 450         }
 451
 452         /* If it's not a multipart message, then do something with it */
 453         if (!is_multipart) {
 454                 part_start = ptr;
 455                 length = 0;
 456                 while (ptr < content_end) {
 457                         ++ptr;
 458                         ++length;
 459                 }
 460                 part_end = content_end;
 461                 /* fix an off-by-one error */
 462                 --part_end;
 463                 --length;
 464
 465                 /* Truncate if the header told us to */
 466                 if ( (content_length > 0) && (length > content_length) ) {
 467                         length = content_length;
 468                 }
 469
 470                 /* Sometimes the "name" field is tacked on to Content-type,
 471                  * and sometimes it's tacked on to Content-disposition.  Use
 472                  * whichever one we have.
 473                  */
 474                 if (strlen(content_disposition_name) > strlen(content_type_name)) {
 475                         name = content_disposition_name;
 476                 }
 477                 else {
 478                         name = content_type_name;
 479                 }
 480
 481                 mime_decode(partnum,
 482                             part_start, length,
 483                             content_type, encoding, disposition,
 484                             name, filename,
 485                             CallBack, NULL, NULL,
 486                             userdata, dont_decode);
 487         }
 488
 489 end_parser:     /* free the buffers!  end the oppression!! */
 490         free(boundary);
 491         free(startary);
 492         free(endary);
 493         free(header);
 494         free(content_type);
 495         free(encoding);
 496         free(content_type_name);
 497         free(content_disposition_name);
 498         free(filename);
 499         free(disposition);
 500 }
 501
 502
 503
 504 /*
 505  * Entry point for the MIME parser.
 506  * (This function expects to be fed HEADERS + CONTENT)
 507  * Note: NULL can be supplied as content_end; in this case, the message is
 508  * considered to have ended when the parser encounters a 0x00 byte.
 509  */
 510 void mime_parser(char *content_start,
 511                 char *content_end,
 512
 513                  void (*CallBack)
 514                   (char *cbname,
 515                    char *cbfilename,
 516                    char *cbpartnum,
 517                    char *cbdisp,
 518                    void *cbcontent,
 519                    char *cbtype,
 520                    size_t cblength,
 521                    char *cbencoding,
 522                    void *cbuserdata),
 523
 524                  void (*PreMultiPartCallBack)
 525                   (char *cbname,
 526                    char *cbfilename,
 527                    char *cbpartnum,
 528                    char *cbdisp,
 529                    void *cbcontent,
 530                    char *cbtype,
 531                    size_t cblength,
 532                    char *cbencoding,
 533                    void *cbuserdata),
 534
 535                  void (*PostMultiPartCallBack)
 536                   (char *cbname,
 537                    char *cbfilename,
 538                    char *cbpartnum,
 539                    char *cbdisp,
 540                    void *cbcontent,
 541                    char *cbtype,
 542                    size_t cblength,
 543                    char *cbencoding,
 544                    void *cbuserdata),
 545
 546                   void *userdata,
 547                   int dont_decode
 548 )
 549 {
 550
 551         the_mime_parser("", content_start, content_end,
 552                         CallBack,
 553                         PreMultiPartCallBack,
 554                         PostMultiPartCallBack,
 555                         userdata, dont_decode);
 556 }