dma.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Simon 'corecode' Schubert <corecode@fs.ei.tum.de>.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include "dfcompat.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/types.h>
  39 #include <sys/queue.h>
  40 #include <sys/stat.h>
  41 #include <sys/time.h>
  42 #include <sys/wait.h>
  43
  44 #include <dirent.h>
  45 #include <err.h>
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <inttypes.h>
  49 #include <paths.h>
  50 #include <pwd.h>
  51 #include <signal.h>
  52 #include <stdarg.h>
  53 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <syslog.h>
  57 #include <unistd.h>
  58
  59 #include "dma.h"
  60
  61
  62 static void deliver(struct qitem *);
  63
  64 struct aliases aliases = LIST_HEAD_INITIALIZER(aliases);
  65 struct strlist tmpfs = SLIST_HEAD_INITIALIZER(tmpfs);
  66 struct authusers authusers = LIST_HEAD_INITIALIZER(authusers);
  67 char username[USERNAME_SIZE];
  68 uid_t useruid;
  69 const char *logident_base;
  70 char errmsg[ERRMSG_SIZE];
  71
  72 static int daemonize = 1;
  73 static int doqueue = 0;
  74
  75 struct config config = {
  76         .smarthost      = NULL,
  77         .port           = 25,
  78         .aliases        = "/etc/aliases",
  79         .spooldir       = "/var/spool/dma",
  80         .authpath       = NULL,
  81         .certfile       = NULL,
  82         .features       = 0,
  83         .mailname       = NULL,
  84         .masquerade_host = NULL,
  85         .masquerade_user = NULL,
  86 };
  87
  88
  89 static void
  90 sighup_handler(int signo)
  91 {
  92         (void)signo;    /* so that gcc doesn't complain */
  93 }
  94
  95 static char *
  96 set_from(struct queue *queue, const char *osender)
  97 {
  98         const char *addr;
  99         char *sender;
 100
 101         if (osender) {
 102                 addr = osender;
 103         } else if (getenv("EMAIL") != NULL) {
 104                 addr = getenv("EMAIL");
 105         } else {
 106                 if (config.masquerade_user)
 107                         addr = config.masquerade_user;
 108                 else
 109                         addr = username;
 110         }
 111
 112         if (!strchr(addr, '@')) {
 113                 const char *from_host = hostname();
 114
 115                 if (config.masquerade_host)
 116                         from_host = config.masquerade_host;
 117
 118                 if (asprintf(&sender, "%s@%s", addr, from_host) <= 0)
 119                         return (NULL);
 120         } else {
 121                 sender = strdup(addr);
 122                 if (sender == NULL)
 123                         return (NULL);
 124         }
 125
 126         if (strchr(sender, '\n') != NULL) {
 127                 errno = EINVAL;
 128                 return (NULL);
 129         }
 130
 131         queue->sender = sender;
 132         return (sender);
 133 }
 134
 135 static int
 136 read_aliases(void)
 137 {
 138         yyin = fopen(config.aliases, "r");
 139         if (yyin == NULL) {
 140                 /*
 141                  * Non-existing aliases file is not a fatal error
 142                  */
 143                 if (errno == ENOENT)
 144                         return (0);
 145                 /* Other problems are. */
 146                 return (-1);
 147         }
 148         if (yyparse())
 149                 return (-1);    /* fatal error, probably malloc() */
 150         fclose(yyin);
 151         return (0);
 152 }
 153
 154 static int
 155 do_alias(struct queue *queue, const char *addr)
 156 {
 157         struct alias *al;
 158         struct stritem *sit;
 159         int aliased = 0;
 160
 161         LIST_FOREACH(al, &aliases, next) {
 162                 if (strcmp(al->alias, addr) != 0)
 163                         continue;
 164                 SLIST_FOREACH(sit, &al->dests, next) {
 165                         if (add_recp(queue, sit->str, EXPAND_ADDR) != 0)
 166                                 return (-1);
 167                 }
 168                 aliased = 1;
 169         }
 170
 171         return (aliased);
 172 }
 173
 174 int
 175 add_recp(struct queue *queue, const char *str, int expand)
 176 {
 177         struct qitem *it, *tit;
 178         struct passwd *pw;
 179         char *host;
 180         int aliased = 0;
 181
 182         it = calloc(1, sizeof(*it));
 183         if (it == NULL)
 184                 return (-1);
 185         it->addr = strdup(str);
 186         if (it->addr == NULL)
 187                 return (-1);
 188
 189         it->sender = queue->sender;
 190         host = strrchr(it->addr, '@');
 191         if (host != NULL &&
 192             (strcmp(host + 1, hostname()) == 0 ||
 193              strcmp(host + 1, "localhost") == 0)) {
 194                 *host = 0;
 195         }
 196         LIST_FOREACH(tit, &queue->queue, next) {
 197                 /* weed out duplicate dests */
 198                 if (strcmp(tit->addr, it->addr) == 0) {
 199                         free(it->addr);
 200                         free(it);
 201                         return (0);
 202                 }
 203         }
 204         LIST_INSERT_HEAD(&queue->queue, it, next);
 205         if (strrchr(it->addr, '@') == NULL) {
 206                 it->remote = 0;
 207                 if (expand) {
 208                         aliased = do_alias(queue, it->addr);
 209                         if (!aliased && expand == EXPAND_WILDCARD)
 210                                 aliased = do_alias(queue, "*");
 211                         if (aliased < 0)
 212                                 return (-1);
 213                         if (aliased) {
 214                                 LIST_REMOVE(it, next);
 215                         } else {
 216                                 /* Local destination, check */
 217                                 pw = getpwnam(it->addr);
 218                                 if (pw == NULL)
 219                                         goto out;
 220                                 /* XXX read .forward */
 221                                 endpwent();
 222                         }
 223                 }
 224         } else {
 225                 it->remote = 1;
 226         }
 227
 228         return (0);
 229
 230 out:
 231         free(it->addr);
 232         free(it);
 233         return (-1);
 234 }
 235
 236 static struct qitem *
 237 go_background(struct queue *queue)
 238 {
 239         struct sigaction sa;
 240         struct qitem *it;
 241         pid_t pid;
 242
 243         if (daemonize && daemon(0, 0) != 0) {
 244                 syslog(LOG_ERR, "can not daemonize: %m");
 245                 exit(1);
 246         }
 247         daemonize = 0;
 248
 249         bzero(&sa, sizeof(sa));
 250         sa.sa_handler = SIG_IGN;
 251         sigaction(SIGCHLD, &sa, NULL);
 252
 253         LIST_FOREACH(it, &queue->queue, next) {
 254                 /* No need to fork for the last dest */
 255                 if (LIST_NEXT(it, next) == NULL)
 256                         goto retit;
 257
 258                 pid = fork();
 259                 switch (pid) {
 260                 case -1:
 261                         syslog(LOG_ERR, "can not fork: %m");
 262                         exit(1);
 263                         break;
 264
 265                 case 0:
 266                         /*
 267                          * Child:
 268                          *
 269                          * return and deliver mail
 270                          */
 271 retit:
 272                         /*
 273                          * If necessary, acquire the queue and * mail files.
 274                          * If this fails, we probably were raced by another
 275                          * process.  It is okay to be raced if we're supposed
 276                          * to flush the queue.
 277                          */
 278                         setlogident("%s", it->queueid);
 279                         switch (acquirespool(it)) {
 280                         case 0:
 281                                 break;
 282                         case 1:
 283                                 if (doqueue)
 284                                         exit(0);
 285                                 syslog(LOG_WARNING, "could not lock queue file");
 286                                 exit(1);
 287                         default:
 288                                 exit(1);
 289                         }
 290                         dropspool(queue, it);
 291                         return (it);
 292
 293                 default:
 294                         /*
 295                          * Parent:
 296                          *
 297                          * fork next child
 298                          */
 299                         break;
 300                 }
 301         }
 302
 303         syslog(LOG_CRIT, "reached dead code");
 304         exit(1);
 305 }
 306
 307 static void
 308 deliver(struct qitem *it)
 309 {
 310         int error;
 311         unsigned int backoff = MIN_RETRY, slept;
 312         struct timeval now;
 313         struct stat st;
 314
 315         snprintf(errmsg, sizeof(errmsg), "unknown bounce reason");
 316
 317 retry:
 318         syslog(LOG_INFO, "trying delivery");
 319
 320         if (it->remote)
 321                 error = deliver_remote(it);
 322         else
 323                 error = deliver_local(it);
 324
 325         switch (error) {
 326         case 0:
 327                 delqueue(it);
 328                 syslog(LOG_INFO, "delivery successful");
 329                 exit(0);
 330
 331         case 1:
 332                 if (stat(it->queuefn, &st) != 0) {
 333                         syslog(LOG_ERR, "lost queue file `%s'", it->queuefn);
 334                         exit(1);
 335                 }
 336                 if (gettimeofday(&now, NULL) == 0 &&
 337                     (now.tv_sec - st.st_mtim.tv_sec > MAX_TIMEOUT)) {
 338                         snprintf(errmsg, sizeof(errmsg),
 339                                  "Could not deliver for the last %d seconds. Giving up.",
 340                                  MAX_TIMEOUT);
 341                         goto bounce;
 342                 }
 343                 for (slept = 0; slept < backoff;) {
 344                         slept += SLEEP_TIMEOUT - sleep(SLEEP_TIMEOUT);
 345                         if (flushqueue_since(slept)) {
 346                                 backoff = MIN_RETRY;
 347                                 goto retry;
 348                         }
 349                 }
 350                 if (slept >= backoff) {
 351                         /* pick the next backoff between [1.5, 2.5) times backoff */
 352                         backoff = backoff + backoff / 2 + random() % backoff;
 353                         if (backoff > MAX_RETRY)
 354                                 backoff = MAX_RETRY;
 355                 }
 356                 goto retry;
 357
 358         case -1:
 359         default:
 360                 break;
 361         }
 362
 363 bounce:
 364         bounce(it, errmsg);
 365         /* NOTREACHED */
 366 }
 367
 368 void
 369 run_queue(struct queue *queue)
 370 {
 371         struct qitem *it;
 372
 373         if (LIST_EMPTY(&queue->queue))
 374                 return;
 375
 376         it = go_background(queue);
 377         deliver(it);
 378         /* NOTREACHED */
 379 }
 380
 381 static void
 382 show_queue(struct queue *queue)
 383 {
 384         struct qitem *it;
 385         int locked = 0; /* XXX */
 386
 387         if (LIST_EMPTY(&queue->queue)) {
 388                 printf("Mail queue is empty\n");
 389                 return;
 390         }
 391
 392         LIST_FOREACH(it, &queue->queue, next) {
 393                 printf("ID\t: %s%s\n"
 394                        "From\t: %s\n"
 395                        "To\t: %s\n",
 396                        it->queueid,
 397                        locked ? "*" : "",
 398                        it->sender, it->addr);
 399
 400                 if (LIST_NEXT(it, next) != NULL)
 401                         printf("--\n");
 402         }
 403 }
 404
 405 /*
 406  * TODO:
 407  *
 408  * - alias processing
 409  * - use group permissions
 410  * - proper sysexit codes
 411  */
 412
 413 int
 414 main(int argc, char **argv)
 415 {
 416         struct sigaction act;
 417         char *sender = NULL;
 418         struct queue queue;
 419         int i, ch;
 420         int nodot = 0, showq = 0, queue_only = 0;
 421         int recp_from_header = 0;
 422
 423         set_username();
 424
 425         /*
 426          * We never run as root.  If called by root, drop permissions
 427          * to the mail user.
 428          */
 429         if (geteuid() == 0 || getuid() == 0) {
 430                 struct passwd *pw;
 431
 432                 errno = 0;
 433                 pw = getpwnam(DMA_ROOT_USER);
 434                 if (pw == NULL) {
 435                         if (errno == 0)
 436                                 errx(1, "user '%s' not found", DMA_ROOT_USER);
 437                         else
 438                                 err(1, "cannot drop root privileges");
 439                 }
 440
 441                 if (setuid(pw->pw_uid) != 0)
 442                         err(1, "cannot drop root privileges");
 443
 444                 if (geteuid() == 0 || getuid() == 0)
 445                         errx(1, "cannot drop root privileges");
 446         }
 447
 448         atexit(deltmp);
 449         init_random();
 450
 451         bzero(&queue, sizeof(queue));
 452         LIST_INIT(&queue.queue);
 453
 454         if (strcmp(argv[0], "mailq") == 0) {
 455                 argv++; argc--;
 456                 showq = 1;
 457                 if (argc != 0)
 458                         errx(1, "invalid arguments");
 459                 goto skipopts;
 460         } else if (strcmp(argv[0], "newaliases") == 0) {
 461                 logident_base = "dma";
 462                 setlogident(NULL);
 463
 464                 if (read_aliases() != 0)
 465                         errx(1, "could not parse aliases file `%s'", config.aliases);
 466                 exit(0);
 467         }
 468
 469         opterr = 0;
 470         while ((ch = getopt(argc, argv, ":A:b:B:C:d:Df:F:h:iL:N:no:O:q:r:R:tUV:vX:")) != -1) {
 471                 switch (ch) {
 472                 case 'A':
 473                         /* -AX is being ignored, except for -A{c,m} */
 474                         if (optarg[0] == 'c' || optarg[0] == 'm') {
 475                                 break;
 476                         }
 477                         /* else FALLTRHOUGH */
 478                 case 'b':
 479                         /* -bX is being ignored, except for -bp */
 480                         if (optarg[0] == 'p') {
 481                                 showq = 1;
 482                                 break;
 483                         } else if (optarg[0] == 'q') {
 484                                 queue_only = 1;
 485                                 break;
 486                         }
 487                         /* else FALLTRHOUGH */
 488                 case 'D':
 489                         daemonize = 0;
 490                         break;
 491                 case 'L':
 492                         logident_base = optarg;
 493                         break;
 494                 case 'f':
 495                 case 'r':
 496                         sender = optarg;
 497                         break;
 498
 499                 case 't':
 500                         recp_from_header = 1;
 501                         break;
 502
 503                 case 'o':
 504                         /* -oX is being ignored, except for -oi */
 505                         if (optarg[0] != 'i')
 506                                 break;
 507                         /* else FALLTRHOUGH */
 508                 case 'O':
 509                         break;
 510                 case 'i':
 511                         nodot = 1;
 512                         break;
 513
 514                 case 'q':
 515                         /* Don't let getopt slup up other arguments */
 516                         if (optarg && *optarg == '-')
 517                                 optind--;
 518                         doqueue = 1;
 519                         break;
 520
 521                 /* Ignored options */
 522                 case 'B':
 523                 case 'C':
 524                 case 'd':
 525                 case 'F':
 526                 case 'h':
 527                 case 'N':
 528                 case 'n':
 529                 case 'R':
 530                 case 'U':
 531                 case 'V':
 532                 case 'v':
 533                 case 'X':
 534                         break;
 535
 536                 case ':':
 537                         if (optopt == 'q') {
 538                                 doqueue = 1;
 539                                 break;
 540                         }
 541                         /* FALLTHROUGH */
 542
 543                 default:
 544                         fprintf(stderr, "invalid argument: `-%c'\n", optopt);
 545                         exit(1);
 546                 }
 547         }
 548         argc -= optind;
 549         argv += optind;
 550         opterr = 1;
 551
 552         if (argc != 0 && (showq || doqueue))
 553                 errx(1, "sending mail and queue operations are mutually exclusive");
 554
 555         if (showq + doqueue > 1)
 556                 errx(1, "conflicting queue operations");
 557
 558 skipopts:
 559         if (logident_base == NULL)
 560                 logident_base = "dma";
 561         setlogident(NULL);
 562
 563         act.sa_handler = sighup_handler;
 564         act.sa_flags = 0;
 565         sigemptyset(&act.sa_mask);
 566         if (sigaction(SIGHUP, &act, NULL) != 0)
 567                 syslog(LOG_WARNING, "can not set signal handler: %m");
 568
 569         parse_conf(CONF_PATH "/dma.conf");
 570
 571         if (config.authpath != NULL)
 572                 parse_authfile(config.authpath);
 573
 574         if (showq) {
 575                 if (load_queue(&queue) < 0)
 576                         errlog(1, "can not load queue");
 577                 show_queue(&queue);
 578                 return (0);
 579         }
 580
 581         if (doqueue) {
 582                 flushqueue_signal();
 583                 if (load_queue(&queue) < 0)
 584                         errlog(1, "can not load queue");
 585                 run_queue(&queue);
 586                 return (0);
 587         }
 588
 589         if (read_aliases() != 0)
 590                 errlog(1, "could not parse aliases file `%s'", config.aliases);
 591
 592         if ((sender = set_from(&queue, sender)) == NULL)
 593                 errlog(1, NULL);
 594
 595         if (newspoolf(&queue) != 0)
 596                 errlog(1, "can not create temp file in `%s'", config.spooldir);
 597
 598         setlogident("%s", queue.id);
 599
 600         for (i = 0; i < argc; i++) {
 601                 if (add_recp(&queue, argv[i], EXPAND_WILDCARD) != 0)
 602                         errlogx(1, "invalid recipient `%s'", argv[i]);
 603         }
 604
 605         if (LIST_EMPTY(&queue.queue) && !recp_from_header)
 606                 errlogx(1, "no recipients");
 607
 608         if (readmail(&queue, nodot, recp_from_header) != 0)
 609                 errlog(1, "can not read mail");
 610
 611         if (LIST_EMPTY(&queue.queue))
 612                 errlogx(1, "no recipients");
 613
 614         if (linkspool(&queue) != 0)
 615                 errlog(1, "can not create spools");
 616
 617         /* From here on the mail is safe. */
 618
 619         if (config.features & DEFER || queue_only)
 620                 return (0);
 621
 622         run_queue(&queue);
 623
 624         /* NOTREACHED */
 625         return (0);
 626 }