webcit/mime_parser.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the MIME parser for Citadel.  Sometimes it actually works.
   5  *
   6  * Copyright (c) 1998-2003 by Art Cancro
   7  * This code is distributed under the terms of the GNU General Public License.
   8  *
   9  */
  10
  11 #include <ctype.h>
  12 #include <stdlib.h>
  13 #ifdef HAVE_UNISTD_H
  14 #include <unistd.h>
  15 #endif
  16 #include <stdio.h>
  17 #ifdef HAVE_FCNTL_H
  18 #include <fcntl.h>
  19 #endif
  20 #include <signal.h>
  21 #include <sys/types.h>
  22 #include <sys/wait.h>
  23 #include <sys/socket.h>
  24 #ifdef HAVE_SYS_TIME_H
  25 #include <sys/time.h>
  26 #endif
  27 #ifdef HAVE_LIMITS_H
  28 #include <limits.h>
  29 #endif
  30 #include <netinet/in.h>
  31 #include <arpa/inet.h>
  32 #include <netdb.h>
  33 #include <string.h>
  34 #include <pwd.h>
  35 #include <errno.h>
  36 #include <stdarg.h>
  37 #include <pthread.h>
  38 #include <signal.h>
  39 #include "webcit.h"
  40 #include "webserver.h"
  41
  42 #include "mime_parser.h"
  43
  44
  45 void extract_key(char *target, char *source, char *key)
  46 {
  47         int a, b;
  48
  49         strcpy(target, source);
  50         for (a = 0; a < strlen(target); ++a) {
  51                 if ((!strncasecmp(&target[a], key, strlen(key)))
  52                     && (target[a + strlen(key)] == '=')) {
  53                         strcpy(target, &target[a + strlen(key) + 1]);
  54                         if (target[0] == 34)
  55                                 strcpy(target, &target[1]);
  56                         for (b = 0; b < strlen(target); ++b)
  57                                 if (target[b] == 34)
  58                                         target[b] = 0;
  59                         return;
  60                 }
  61         }
  62         strcpy(target, "");
  63 }
  64
  65
  66 /*
  67  * For non-multipart messages, we need to generate a quickie partnum of "1"
  68  * to return to callback functions.  Some callbacks demand it.
  69  */
  70 char *fixed_partnum(char *supplied_partnum) {
  71         if (supplied_partnum == NULL) return "1";
  72         if (strlen(supplied_partnum)==0) return "1";
  73         return supplied_partnum;
  74 }
  75
  76
  77
  78 /*
  79  * Convert "quoted-printable" to binary.  Returns number of bytes decoded.
  80  */
  81 int CtdlDecodeQuotedPrintable(char *decoded, char *encoded, int sourcelen) {
  82         char buf[SIZ];
  83         int buf_length = 0;
  84         int soft_line_break = 0;
  85         int ch;
  86         int decoded_length = 0;
  87         int i;
  88
  89         decoded[0] = 0;
  90         decoded_length = 0;
  91         buf[0] = 0;
  92         buf_length = 0;
  93
  94         for (i = 0; i < sourcelen; ++i) {
  95
  96                 buf[buf_length++] = encoded[i];
  97
  98                 if ( (encoded[i] == '\n')
  99                    || (encoded[i] == 0)
 100                    || (i == (sourcelen-1)) ) {
 101                         buf[buf_length++] = 0;
 102
 103                         /*** begin -- process one line ***/
 104
 105                         if (buf[strlen(buf)-1] == '\n') {
 106                                 buf[strlen(buf)-1] = 0;
 107                         }
 108                         if (buf[strlen(buf)-1] == '\r') {
 109                                 buf[strlen(buf)-1] = 0;
 110                         }
 111                         while (isspace(buf[strlen(buf)-1])) {
 112                                 buf[strlen(buf)-1] = 0;
 113                         }
 114                         soft_line_break = 0;
 115
 116                         while (strlen(buf) > 0) {
 117                                 if (!strcmp(buf, "=")) {
 118                                         soft_line_break = 1;
 119                                         strcpy(buf, "");
 120                                 } else if ((strlen(buf)>=3) && (buf[0]=='=')) {
 121                                         sscanf(&buf[1], "%02x", &ch);
 122                                         decoded[decoded_length++] = ch;
 123                                         strcpy(buf, &buf[3]);
 124                                 } else {
 125                                         decoded[decoded_length++] = buf[0];
 126                                         strcpy(buf, &buf[1]);
 127                                 }
 128                         }
 129                         if (soft_line_break == 0) {
 130                                 decoded[decoded_length++] = '\r';
 131                                 decoded[decoded_length++] = '\n';
 132                         }
 133                         buf_length = 0;
 134                         /*** end -- process one line ***/
 135                 }
 136         }
 137
 138         decoded[decoded_length++] = 0;
 139         return(decoded_length);
 140 }
 141
 142 /*
 143  * Given a message or message-part body and a length, handle any necessary
 144  * decoding and pass the request up the stack.
 145  */
 146 void mime_decode(char *partnum,
 147                  char *part_start, size_t length,
 148                  char *content_type, char *encoding,
 149                  char *disposition,
 150                  char *name, char *filename,
 151                  void (*CallBack)
 152                   (char *cbname,
 153                    char *cbfilename,
 154                    char *cbpartnum,
 155                    char *cbdisp,
 156                    void *cbcontent,
 157                    char *cbtype,
 158                    size_t cblength,
 159                    char *cbencoding,
 160                    void *cbuserdata),
 161                  void (*PreMultiPartCallBack)
 162                   (char *cbname,
 163                    char *cbfilename,
 164                    char *cbpartnum,
 165                    char *cbdisp,
 166                    void *cbcontent,
 167                    char *cbtype,
 168                    size_t cblength,
 169                    char *cbencoding,
 170                    void *cbuserdata),
 171                  void (*PostMultiPartCallBack)
 172                   (char *cbname,
 173                    char *cbfilename,
 174                    char *cbpartnum,
 175                    char *cbdisp,
 176                    void *cbcontent,
 177                    char *cbtype,
 178                    size_t cblength,
 179                    char *cbencoding,
 180                    void *cbuserdata),
 181                   void *userdata,
 182                   int dont_decode
 183 )
 184 {
 185
 186         char *decoded;
 187         size_t bytes_decoded = 0;
 188
 189         /* Some encodings aren't really encodings */
 190         if (!strcasecmp(encoding, "7bit"))
 191                 strcpy(encoding, "");
 192         if (!strcasecmp(encoding, "8bit"))
 193                 strcpy(encoding, "");
 194         if (!strcasecmp(encoding, "binary"))
 195                 strcpy(encoding, "");
 196
 197         /* If this part is not encoded, send as-is */
 198         if ( (strlen(encoding) == 0) || (dont_decode)) {
 199                 if (CallBack != NULL) {
 200                         CallBack(name, filename, fixed_partnum(partnum),
 201                                 disposition, part_start,
 202                                 content_type, length, encoding, userdata);
 203                         }
 204                 return;
 205         }
 206
 207         if ((strcasecmp(encoding, "base64"))
 208             && (strcasecmp(encoding, "quoted-printable"))) {
 209                 return;
 210         }
 211         /*
 212          * Allocate a buffer for the decoded data.  The output buffer is the
 213          * same size as the input buffer; this assumes that the decoded data
 214          * will never be larger than the encoded data.  This is a safe
 215          * assumption with base64, uuencode, and quoted-printable.
 216          */
 217         decoded = mallok(length+2048);
 218         if (decoded == NULL) {
 219                 return;
 220         }
 221
 222         if (!strcasecmp(encoding, "base64")) {
 223                 bytes_decoded = CtdlDecodeBase64(decoded, part_start, length);
 224         }
 225         else if (!strcasecmp(encoding, "quoted-printable")) {
 226                 bytes_decoded = CtdlDecodeQuotedPrintable(decoded,
 227                                                         part_start, length);
 228         }
 229
 230         if (bytes_decoded > 0) if (CallBack != NULL) {
 231                 CallBack(name, filename, fixed_partnum(partnum),
 232                         disposition, decoded,
 233                         content_type, bytes_decoded, "binary", userdata);
 234         }
 235
 236         phree(decoded);
 237 }
 238
 239 /*
 240  * Break out the components of a multipart message
 241  * (This function expects to be fed HEADERS + CONTENT)
 242  * Note: NULL can be supplied as content_end; in this case, the message is
 243  * considered to have ended when the parser encounters a 0x00 byte.
 244  */
 245 void the_mime_parser(char *partnum,
 246                      char *content_start, char *content_end,
 247                      void (*CallBack)
 248                       (char *cbname,
 249                        char *cbfilename,
 250                        char *cbpartnum,
 251                        char *cbdisp,
 252                        void *cbcontent,
 253                        char *cbtype,
 254                        size_t cblength,
 255                        char *cbencoding,
 256                        void *cbuserdata),
 257                      void (*PreMultiPartCallBack)
 258                       (char *cbname,
 259                        char *cbfilename,
 260                        char *cbpartnum,
 261                        char *cbdisp,
 262                        void *cbcontent,
 263                        char *cbtype,
 264                        size_t cblength,
 265                        char *cbencoding,
 266                        void *cbuserdata),
 267                      void (*PostMultiPartCallBack)
 268                       (char *cbname,
 269                        char *cbfilename,
 270                        char *cbpartnum,
 271                        char *cbdisp,
 272                        void *cbcontent,
 273                        char *cbtype,
 274                        size_t cblength,
 275                        char *cbencoding,
 276                        void *cbuserdata),
 277                       void *userdata,
 278                       int dont_decode
 279 )
 280 {
 281
 282         char *ptr;
 283         char *part_start, *part_end = NULL;
 284         char buf[SIZ];
 285         char *header;
 286         char *boundary;
 287         char *startary;
 288         char *endary;
 289         char *content_type;
 290         size_t content_length;
 291         char *encoding;
 292         char *disposition;
 293         char *name = NULL;
 294         char *content_type_name;
 295         char *content_disposition_name;
 296         char *filename;
 297         int is_multipart;
 298         int part_seq = 0;
 299         int i;
 300         size_t length;
 301         char nested_partnum[SIZ];
 302
 303         ptr = content_start;
 304         content_length = 0;
 305
 306         boundary = mallok(SIZ);
 307         memset(boundary, 0, SIZ);
 308
 309         startary = mallok(SIZ);
 310         memset(startary, 0, SIZ);
 311
 312         endary = mallok(SIZ);
 313         memset(endary, 0, SIZ);
 314
 315         header = mallok(SIZ);
 316         memset(header, 0, SIZ);
 317
 318         content_type = mallok(SIZ);
 319         memset(content_type, 0, SIZ);
 320
 321         encoding = mallok(SIZ);
 322         memset(encoding, 0, SIZ);
 323
 324         content_type_name = mallok(SIZ);
 325         memset(content_type_name, 0, SIZ);
 326
 327         content_disposition_name = mallok(SIZ);
 328         memset(content_disposition_name, 0, SIZ);
 329
 330         filename = mallok(SIZ);
 331         memset(filename, 0, SIZ);
 332
 333         disposition = mallok(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                 if (!isspace(buf[0])) {
 353                         if (!strncasecmp(header, "Content-type: ", 14)) {
 354                                 strcpy(content_type, &header[14]);
 355                                 extract_key(content_type_name, content_type, "name");
 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,
 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                 do {
 409                         if ( (!strncasecmp(ptr, startary, strlen(startary)))
 410                            || (!strncasecmp(ptr, endary, strlen(endary))) ) {
 411                                 if (part_start != NULL) {
 412                                         if (strlen(partnum) > 0) {
 413                                                 snprintf(nested_partnum,
 414                                                          sizeof nested_partnum,
 415                                                          "%s.%d", partnum,
 416                                                          ++part_seq);
 417                                         }
 418                                         else {
 419                                                 snprintf(nested_partnum,
 420                                                          sizeof nested_partnum,
 421                                                          "%d", ++part_seq);
 422                                         }
 423                                         the_mime_parser(nested_partnum,
 424                                                     part_start, part_end,
 425                                                         CallBack,
 426                                                         PreMultiPartCallBack,
 427                                                         PostMultiPartCallBack,
 428                                                         userdata,
 429                                                         dont_decode);
 430                                 }
 431                                 ptr = memreadline(ptr, buf, SIZ);
 432                                 part_start = ptr;
 433                         }
 434                         else {
 435                                 part_end = ptr;
 436                                 ++ptr;
 437                         }
 438                         /* If we pass out of scope in the MIME multipart (by
 439                          * hitting the end boundary), force the pointer out
 440                          * of scope so this loop ends.
 441                          */
 442                         if (ptr < content_end) {
 443                                 if (!strcasecmp(ptr, endary)) {
 444                                         ptr = content_end++;
 445                                 }
 446                         }
 447                 } while (ptr <= content_end);
 448                 if (PostMultiPartCallBack != NULL) {
 449                         PostMultiPartCallBack("", "", partnum, "", NULL,
 450                                 content_type, 0, encoding, userdata);
 451                 }
 452                 goto end_parser;
 453         }
 454
 455         /* If it's not a multipart message, then do something with it */
 456         if (!is_multipart) {
 457                 part_start = ptr;
 458                 length = 0;
 459                 while (ptr < content_end) {
 460                         ++ptr;
 461                         ++length;
 462                 }
 463                 part_end = content_end;
 464                 /* fix an off-by-one error */
 465                 --part_end;
 466                 --length;
 467
 468                 /* Truncate if the header told us to */
 469                 if ( (content_length > 0) && (length > content_length) ) {
 470                         length = content_length;
 471                 }
 472
 473                 /* Sometimes the "name" field is tacked on to Content-type,
 474                  * and sometimes it's tacked on to Content-disposition.  Use
 475                  * whichever one we have.
 476                  */
 477                 if (strlen(content_disposition_name) > strlen(content_type_name)) {
 478                         name = content_disposition_name;
 479                 }
 480                 else {
 481                         name = content_type_name;
 482                 }
 483
 484                 mime_decode(partnum,
 485                             part_start, length,
 486                             content_type, encoding, disposition,
 487                             name, filename,
 488                             CallBack, NULL, NULL,
 489                             userdata, dont_decode);
 490         }
 491
 492 end_parser:     /* free the buffers!  end the oppression!! */
 493         phree(boundary);
 494         phree(startary);
 495         phree(endary);
 496         phree(header);
 497         phree(content_type);
 498         phree(encoding);
 499         phree(content_type_name);
 500         phree(content_disposition_name);
 501         phree(filename);
 502         phree(disposition);
 503 }
 504
 505
 506
 507 /*
 508  * Entry point for the MIME parser.
 509  * (This function expects to be fed HEADERS + CONTENT)
 510  * Note: NULL can be supplied as content_end; in this case, the message is
 511  * considered to have ended when the parser encounters a 0x00 byte.
 512  */
 513 void mime_parser(char *content_start,
 514                 char *content_end,
 515
 516                  void (*CallBack)
 517                   (char *cbname,
 518                    char *cbfilename,
 519                    char *cbpartnum,
 520                    char *cbdisp,
 521                    void *cbcontent,
 522                    char *cbtype,
 523                    size_t cblength,
 524                    char *cbencoding,
 525                    void *cbuserdata),
 526
 527                  void (*PreMultiPartCallBack)
 528                   (char *cbname,
 529                    char *cbfilename,
 530                    char *cbpartnum,
 531                    char *cbdisp,
 532                    void *cbcontent,
 533                    char *cbtype,
 534                    size_t cblength,
 535                    char *cbencoding,
 536                    void *cbuserdata),
 537
 538                  void (*PostMultiPartCallBack)
 539                   (char *cbname,
 540                    char *cbfilename,
 541                    char *cbpartnum,
 542                    char *cbdisp,
 543                    void *cbcontent,
 544                    char *cbtype,
 545                    size_t cblength,
 546                    char *cbencoding,
 547                    void *cbuserdata),
 548
 549                   void *userdata,
 550                   int dont_decode
 551 )
 552 {
 553
 554         the_mime_parser("", content_start, content_end,
 555                         CallBack,
 556                         PreMultiPartCallBack,
 557                         PostMultiPartCallBack,
 558                         userdata, dont_decode);
 559 }
 560