mail.c

   1 /*
   2  * Copyright (c) 2008-2014, Simon Schubert <2@0x2c.org>.
   3  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to The DragonFly Project
   6  * by Simon Schubert <2@0x2c.org>.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <errno.h>
  37 #include <inttypes.h>
  38 #include <signal.h>
  39 #include <syslog.h>
  40 #include <unistd.h>
  41
  42 #include "dma.h"
  43
  44 void
  45 bounce(struct qitem *it, const char *reason)
  46 {
  47         struct queue bounceq;
  48         char line[1000];
  49         size_t pos;
  50         int error;
  51
  52         /* Don't bounce bounced mails */
  53         if (it->sender[0] == 0) {
  54                 syslog(LOG_INFO, "can not bounce a bounce message, discarding");
  55                 exit(EX_SOFTWARE);
  56         }
  57
  58         bzero(&bounceq, sizeof(bounceq));
  59         LIST_INIT(&bounceq.queue);
  60         bounceq.sender = "";
  61         if (add_recp(&bounceq, it->sender, EXPAND_WILDCARD) != 0)
  62                 goto fail;
  63
  64         if (newspoolf(&bounceq) != 0)
  65                 goto fail;
  66
  67         syslog(LOG_ERR, "delivery failed, bouncing as %s", bounceq.id);
  68         setlogident("%s", bounceq.id);
  69
  70         error = fprintf(bounceq.mailf,
  71                 "Received: from MAILER-DAEMON\n"
  72                 "\tid %s\n"
  73                 "\tby %s (%s);\n"
  74                 "\t%s\n"
  75                 "X-Original-To: <%s>\n"
  76                 "From: MAILER-DAEMON <>\n"
  77                 "To: %s\n"
  78                 "Subject: Mail delivery failed\n"
  79                 "Message-Id: <%s@%s>\n"
  80                 "Date: %s\n"
  81                 "\n"
  82                 "This is the %s at %s.\n"
  83                 "\n"
  84                 "There was an error delivering your mail to <%s>.\n"
  85                 "\n"
  86                 "%s\n"
  87                 "\n"
  88                 "%s\n"
  89                 "\n",
  90                 bounceq.id,
  91                 hostname(), VERSION,
  92                 rfc822date(),
  93                 it->addr,
  94                 it->sender,
  95                 bounceq.id, hostname(),
  96                 rfc822date(),
  97                 VERSION, hostname(),
  98                 it->addr,
  99                 reason,
 100                 config.features & FULLBOUNCE ?
 101                     "Original message follows." :
 102                     "Message headers follow.");
 103         if (error < 0)
 104                 goto fail;
 105
 106         if (fseek(it->mailf, 0, SEEK_SET) != 0)
 107                 goto fail;
 108         if (config.features & FULLBOUNCE) {
 109                 while ((pos = fread(line, 1, sizeof(line), it->mailf)) > 0) {
 110                         if (fwrite(line, 1, pos, bounceq.mailf) != pos)
 111                                 goto fail;
 112                 }
 113         } else {
 114                 while (!feof(it->mailf)) {
 115                         if (fgets(line, sizeof(line), it->mailf) == NULL)
 116                                 break;
 117                         if (line[0] == '\n')
 118                                 break;
 119                         if (fwrite(line, strlen(line), 1, bounceq.mailf) != 1)
 120                                 goto fail;
 121                 }
 122         }
 123
 124         if (linkspool(&bounceq) != 0)
 125                 goto fail;
 126         /* bounce is safe */
 127
 128         delqueue(it);
 129
 130         run_queue(&bounceq);
 131         /* NOTREACHED */
 132
 133 fail:
 134         syslog(LOG_CRIT, "error creating bounce: %m");
 135         delqueue(it);
 136         exit(EX_IOERR);
 137 }
 138
 139 struct parse_state {
 140         char addr[1000];
 141         int pos;
 142
 143         enum {
 144                 NONE = 0,
 145                 START,
 146                 MAIN,
 147                 EOL,
 148                 QUIT
 149         } state;
 150         int comment;
 151         int quote;
 152         int brackets;
 153         int esc;
 154 };
 155
 156 /*
 157  * Simplified RFC2822 header/address parsing.
 158  * We copy escapes and quoted strings directly, since
 159  * we have to pass them like this to the mail server anyways.
 160  * XXX local addresses will need treatment
 161  */
 162 static int
 163 parse_addrs(struct parse_state *ps, char *s, struct queue *queue)
 164 {
 165         char *addr;
 166
 167 again:
 168         switch (ps->state) {
 169         case NONE:
 170                 return (-1);
 171
 172         case START:
 173                 /* init our data */
 174                 bzero(ps, sizeof(*ps));
 175
 176                 /* skip over header name */
 177                 while (*s != ':')
 178                         s++;
 179                 s++;
 180                 ps->state = MAIN;
 181                 break;
 182
 183         case MAIN:
 184                 /* all fine */
 185                 break;
 186
 187         case EOL:
 188                 switch (*s) {
 189                 case ' ':
 190                 case '\t':
 191                         s++;
 192                         /* continue */
 193                         break;
 194
 195                 default:
 196                         ps->state = QUIT;
 197                         if (ps->pos != 0)
 198                                 goto newaddr;
 199                         return (0);
 200                 }
 201
 202         case QUIT:
 203                 return (0);
 204         }
 205
 206         for (; *s != 0; s++) {
 207                 if (ps->esc) {
 208                         ps->esc = 0;
 209
 210                         switch (*s) {
 211                         case '\r':
 212                         case '\n':
 213                                 goto err;
 214
 215                         default:
 216                                 goto copy;
 217                         }
 218                 }
 219
 220                 if (ps->quote) {
 221                         switch (*s) {
 222                         case '"':
 223                                 ps->quote = 0;
 224                                 goto copy;
 225
 226                         case '\\':
 227                                 ps->esc = 1;
 228                                 goto copy;
 229
 230                         case '\r':
 231                         case '\n':
 232                                 goto eol;
 233
 234                         default:
 235                                 goto copy;
 236                         }
 237                 }
 238
 239                 switch (*s) {
 240                 case '(':
 241                         ps->comment++;
 242                         break;
 243
 244                 case ')':
 245                         if (ps->comment)
 246                                 ps->comment--;
 247                         else
 248                                 goto err;
 249                         goto skip;
 250
 251                 case '"':
 252                         ps->quote = 1;
 253                         goto copy;
 254
 255                 case '\\':
 256                         ps->esc = 1;
 257                         goto copy;
 258
 259                 case '\r':
 260                 case '\n':
 261                         goto eol;
 262                 }
 263
 264                 if (ps->comment)
 265                         goto skip;
 266
 267                 switch (*s) {
 268                 case ' ':
 269                 case '\t':
 270                         /* ignore whitespace */
 271                         goto skip;
 272
 273                 case '<':
 274                         /* this is the real address now */
 275                         ps->brackets = 1;
 276                         ps->pos = 0;
 277                         goto skip;
 278
 279                 case '>':
 280                         if (!ps->brackets)
 281                                 goto err;
 282                         ps->brackets = 0;
 283
 284                         s++;
 285                         goto newaddr;
 286
 287                 case ':':
 288                         /* group - ignore */
 289                         ps->pos = 0;
 290                         goto skip;
 291
 292                 case ',':
 293                 case ';':
 294                         /*
 295                          * Next address, copy previous one.
 296                          * However, we might be directly after
 297                          * a <address>, or have two consecutive
 298                          * commas.
 299                          * Skip the comma unless there is
 300                          * really something to copy.
 301                          */
 302                         if (ps->pos == 0)
 303                                 goto skip;
 304                         s++;
 305                         goto newaddr;
 306
 307                 default:
 308                         goto copy;
 309                 }
 310
 311 copy:
 312                 if (ps->comment)
 313                         goto skip;
 314
 315                 if (ps->pos + 1 == sizeof(ps->addr))
 316                         goto err;
 317                 ps->addr[ps->pos++] = *s;
 318
 319 skip:
 320                 ;
 321         }
 322
 323 eol:
 324         ps->state = EOL;
 325         return (0);
 326
 327 err:
 328         ps->state = QUIT;
 329         return (-1);
 330
 331 newaddr:
 332         ps->addr[ps->pos] = 0;
 333         ps->pos = 0;
 334         addr = strdup(ps->addr);
 335         if (addr == NULL)
 336                 errlog(EX_SOFTWARE, NULL);
 337
 338         if (add_recp(queue, addr, EXPAND_WILDCARD) != 0)
 339                 errlogx(EX_DATAERR, "invalid recipient `%s'", addr);
 340
 341         goto again;
 342 }
 343
 344 int
 345 readmail(struct queue *queue, int nodot, int recp_from_header)
 346 {
 347         struct parse_state parse_state;
 348         char line[1000];        /* by RFC2822 */
 349         size_t linelen;
 350         size_t error;
 351         int had_headers = 0;
 352         int had_from = 0;
 353         int had_messagid = 0;
 354         int had_date = 0;
 355         int had_last_line = 0;
 356         int nocopy = 0;
 357
 358         parse_state.state = NONE;
 359
 360         error = fprintf(queue->mailf,
 361                 "Received: from %s (uid %d)\n"
 362                 "\t(envelope-from %s)\n"
 363                 "\tid %s\n"
 364                 "\tby %s (%s);\n"
 365                 "\t%s\n",
 366                 username, useruid,
 367                 queue->sender,
 368                 queue->id,
 369                 hostname(), VERSION,
 370                 rfc822date());
 371         if ((ssize_t)error < 0)
 372                 return (-1);
 373
 374         while (!feof(stdin)) {
 375                 if (fgets(line, sizeof(line) - 1, stdin) == NULL)
 376                         break;
 377                 if (had_last_line)
 378                         errlogx(EX_DATAERR, "bad mail input format:"
 379                                 " from %s (uid %d) (envelope-from %s)",
 380                                 username, useruid, queue->sender);
 381                 linelen = strlen(line);
 382                 if (linelen == 0 || line[linelen - 1] != '\n') {
 383                         /*
 384                          * This line did not end with a newline character.
 385                          * If we fix it, it better be the last line of
 386                          * the file.
 387                          */
 388                         line[linelen] = '\n';
 389                         line[linelen + 1] = 0;
 390                         had_last_line = 1;
 391                 }
 392                 if (!had_headers) {
 393                         /*
 394                          * Unless this is a continuation, switch of
 395                          * the Bcc: nocopy flag.
 396                          */
 397                         if (!(line[0] == ' ' || line[0] == '\t'))
 398                                 nocopy = 0;
 399
 400                         if (strprefixcmp(line, "Date:") == 0)
 401                                 had_date = 1;
 402                         else if (strprefixcmp(line, "Message-Id:") == 0)
 403                                 had_messagid = 1;
 404                         else if (strprefixcmp(line, "From:") == 0)
 405                                 had_from = 1;
 406                         else if (strprefixcmp(line, "Bcc:") == 0)
 407                                 nocopy = 1;
 408
 409                         if (parse_state.state != NONE) {
 410                                 if (parse_addrs(&parse_state, line, queue) < 0) {
 411                                         errlogx(EX_DATAERR, "invalid address in header\n");
 412                                         /* NOTREACHED */
 413                                 }
 414                         }
 415
 416                         if (recp_from_header && (
 417                                         strprefixcmp(line, "To:") == 0 ||
 418                                         strprefixcmp(line, "Cc:") == 0 ||
 419                                         strprefixcmp(line, "Bcc:") == 0)) {
 420                                 parse_state.state = START;
 421                                 if (parse_addrs(&parse_state, line, queue) < 0) {
 422                                         errlogx(EX_DATAERR, "invalid address in header\n");
 423                                         /* NOTREACHED */
 424                                 }
 425                         }
 426                 }
 427
 428                 if (strcmp(line, "\n") == 0 && !had_headers) {
 429                         had_headers = 1;
 430                         while (!had_date || !had_messagid || !had_from) {
 431                                 if (!had_date) {
 432                                         had_date = 1;
 433                                         snprintf(line, sizeof(line), "Date: %s\n", rfc822date());
 434                                 } else if (!had_messagid) {
 435                                         /* XXX msgid, assign earlier and log? */
 436                                         had_messagid = 1;
 437                                         snprintf(line, sizeof(line), "Message-Id: <%"PRIxMAX".%s.%"PRIxMAX"@%s>\n",
 438                                                  (uintmax_t)time(NULL),
 439                                                  queue->id,
 440                                                  (uintmax_t)random(),
 441                                                  hostname());
 442                                 } else if (!had_from) {
 443                                         had_from = 1;
 444                                         snprintf(line, sizeof(line), "From: <%s>\n", queue->sender);
 445                                 }
 446                                 if (fwrite(line, strlen(line), 1, queue->mailf) != 1)
 447                                         return (-1);
 448                         }
 449                         strcpy(line, "\n");
 450                 }
 451                 if (!nodot && linelen == 2 && line[0] == '.')
 452                         break;
 453                 if (!nocopy) {
 454                         if (fwrite(line, strlen(line), 1, queue->mailf) != 1)
 455                                 return (-1);
 456                 }
 457         }
 458
 459         return (0);
 460 }