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         char *sender;
  99
 100         if (osender) {
 101                 sender = strdup(osender);
 102                 if (sender == NULL)
 103                         return (NULL);
 104         } else if (getenv("EMAIL") != NULL) {
 105                 sender = strdup(getenv("EMAIL"));
 106                 if (sender == NULL)
 107                         return (NULL);
 108         } else {
 109                 const char *from_user = username;
 110                 const char *from_host = hostname();
 111
 112                 if (config.masquerade_user)
 113                         from_user = config.masquerade_user;
 114                 if (config.masquerade_host)
 115                         from_host = config.masquerade_host;
 116                 if (asprintf(&sender, "%s@%s", from_user, from_host) <= 0)
 117                         return (NULL);
 118         }
 119
 120         if (strchr(sender, '\n') != NULL) {
 121                 errno = EINVAL;
 122                 return (NULL);
 123         }
 124
 125         queue->sender = sender;
 126         return (sender);
 127 }
 128
 129 static int
 130 read_aliases(void)
 131 {
 132         yyin = fopen(config.aliases, "r");
 133         if (yyin == NULL) {
 134                 /*
 135                  * Non-existing aliases file is not a fatal error
 136                  */
 137                 if (errno == ENOENT)
 138                         return (0);
 139                 /* Other problems are. */
 140                 return (-1);
 141         }
 142         if (yyparse())
 143                 return (-1);    /* fatal error, probably malloc() */
 144         fclose(yyin);
 145         return (0);
 146 }
 147
 148 static int
 149 do_alias(struct queue *queue, const char *addr)
 150 {
 151         struct alias *al;
 152         struct stritem *sit;
 153         int aliased = 0;
 154
 155         LIST_FOREACH(al, &aliases, next) {
 156                 if (strcmp(al->alias, addr) != 0)
 157                         continue;
 158                 SLIST_FOREACH(sit, &al->dests, next) {
 159                         if (add_recp(queue, sit->str, EXPAND_ADDR) != 0)
 160                                 return (-1);
 161                 }
 162                 aliased = 1;
 163         }
 164
 165         return (aliased);
 166 }
 167
 168 int
 169 add_recp(struct queue *queue, const char *str, int expand)
 170 {
 171         struct qitem *it, *tit;
 172         struct passwd *pw;
 173         char *host;
 174         int aliased = 0;
 175
 176         it = calloc(1, sizeof(*it));
 177         if (it == NULL)
 178                 return (-1);
 179         it->addr = strdup(str);
 180         if (it->addr == NULL)
 181                 return (-1);
 182
 183         it->sender = queue->sender;
 184         host = strrchr(it->addr, '@');
 185         if (host != NULL &&
 186             (strcmp(host + 1, hostname()) == 0 ||
 187              strcmp(host + 1, "localhost") == 0)) {
 188                 *host = 0;
 189         }
 190         LIST_FOREACH(tit, &queue->queue, next) {
 191                 /* weed out duplicate dests */
 192                 if (strcmp(tit->addr, it->addr) == 0) {
 193                         free(it->addr);
 194                         free(it);
 195                         return (0);
 196                 }
 197         }
 198         LIST_INSERT_HEAD(&queue->queue, it, next);
 199         if (strrchr(it->addr, '@') == NULL) {
 200                 it->remote = 0;
 201                 if (expand) {
 202                         aliased = do_alias(queue, it->addr);
 203                         if (!aliased && expand == EXPAND_WILDCARD)
 204                                 aliased = do_alias(queue, "*");
 205                         if (aliased < 0)
 206                                 return (-1);
 207                         if (aliased) {
 208                                 LIST_REMOVE(it, next);
 209                         } else {
 210                                 /* Local destination, check */
 211                                 pw = getpwnam(it->addr);
 212                                 if (pw == NULL)
 213                                         goto out;
 214                                 /* XXX read .forward */
 215                                 endpwent();
 216                         }
 217                 }
 218         } else {
 219                 it->remote = 1;
 220         }
 221
 222         return (0);
 223
 224 out:
 225         free(it->addr);
 226         free(it);
 227         return (-1);
 228 }
 229
 230 static struct qitem *
 231 go_background(struct queue *queue)
 232 {
 233         struct sigaction sa;
 234         struct qitem *it;
 235         pid_t pid;
 236
 237         if (daemonize && daemon(0, 0) != 0) {
 238                 syslog(LOG_ERR, "can not daemonize: %m");
 239                 exit(1);
 240         }
 241         daemonize = 0;
 242
 243         bzero(&sa, sizeof(sa));
 244         sa.sa_handler = SIG_IGN;
 245         sigaction(SIGCHLD, &sa, NULL);
 246
 247         LIST_FOREACH(it, &queue->queue, next) {
 248                 /* No need to fork for the last dest */
 249                 if (LIST_NEXT(it, next) == NULL)
 250                         goto retit;
 251
 252                 pid = fork();
 253                 switch (pid) {
 254                 case -1:
 255                         syslog(LOG_ERR, "can not fork: %m");
 256                         exit(1);
 257                         break;
 258
 259                 case 0:
 260                         /*
 261                          * Child:
 262                          *
 263                          * return and deliver mail
 264                          */
 265 retit:
 266                         /*
 267                          * If necessary, acquire the queue and * mail files.
 268                          * If this fails, we probably were raced by another
 269                          * process.  It is okay to be raced if we're supposed
 270                          * to flush the queue.
 271                          */
 272                         setlogident("%s", it->queueid);
 273                         switch (acquirespool(it)) {
 274                         case 0:
 275                                 break;
 276                         case 1:
 277                                 if (doqueue)
 278                                         exit(0);
 279                                 syslog(LOG_WARNING, "could not lock queue file");
 280                                 exit(1);
 281                         default:
 282                                 exit(1);
 283                         }
 284                         dropspool(queue, it);
 285                         return (it);
 286
 287                 default:
 288                         /*
 289                          * Parent:
 290                          *
 291                          * fork next child
 292                          */
 293                         break;
 294                 }
 295         }
 296
 297         syslog(LOG_CRIT, "reached dead code");
 298         exit(1);
 299 }
 300
 301 static void
 302 deliver(struct qitem *it)
 303 {
 304         int error;
 305         unsigned int backoff = MIN_RETRY;
 306         struct timeval now;
 307         struct stat st;
 308
 309         snprintf(errmsg, sizeof(errmsg), "unknown bounce reason");
 310
 311 retry:
 312         syslog(LOG_INFO, "trying delivery");
 313
 314         if (it->remote)
 315                 error = deliver_remote(it);
 316         else
 317                 error = deliver_local(it);
 318
 319         switch (error) {
 320         case 0:
 321                 delqueue(it);
 322                 syslog(LOG_INFO, "delivery successful");
 323                 exit(0);
 324
 325         case 1:
 326                 if (stat(it->queuefn, &st) != 0) {
 327                         syslog(LOG_ERR, "lost queue file `%s'", it->queuefn);
 328                         exit(1);
 329                 }
 330                 if (gettimeofday(&now, NULL) == 0 &&
 331                     (now.tv_sec - st.st_mtim.tv_sec > MAX_TIMEOUT)) {
 332                         snprintf(errmsg, sizeof(errmsg),
 333                                  "Could not deliver for the last %d seconds. Giving up.",
 334                                  MAX_TIMEOUT);
 335                         goto bounce;
 336                 }
 337                 if (sleep(backoff) == 0) {
 338                         /* pick the next backoff between [1.5, 2.5) times backoff */
 339                         backoff = backoff + backoff / 2 + random() % backoff;
 340                         if (backoff > MAX_RETRY)
 341                                 backoff = MAX_RETRY;
 342                 }
 343                 goto retry;
 344
 345         case -1:
 346         default:
 347                 break;
 348         }
 349
 350 bounce:
 351         bounce(it, errmsg);
 352         /* NOTREACHED */
 353 }
 354
 355 void
 356 run_queue(struct queue *queue)
 357 {
 358         struct qitem *it;
 359
 360         if (LIST_EMPTY(&queue->queue))
 361                 return;
 362
 363         it = go_background(queue);
 364         deliver(it);
 365         /* NOTREACHED */
 366 }
 367
 368 static void
 369 show_queue(struct queue *queue)
 370 {
 371         struct qitem *it;
 372         int locked = 0; /* XXX */
 373
 374         if (LIST_EMPTY(&queue->queue)) {
 375                 printf("Mail queue is empty\n");
 376                 return;
 377         }
 378
 379         LIST_FOREACH(it, &queue->queue, next) {
 380                 printf("ID\t: %s%s\n"
 381                        "From\t: %s\n"
 382                        "To\t: %s\n",
 383                        it->queueid,
 384                        locked ? "*" : "",
 385                        it->sender, it->addr);
 386
 387                 if (LIST_NEXT(it, next) != NULL)
 388                         printf("--\n");
 389         }
 390 }
 391
 392 /*
 393  * TODO:
 394  *
 395  * - alias processing
 396  * - use group permissions
 397  * - proper sysexit codes
 398  */
 399
 400 int
 401 main(int argc, char **argv)
 402 {
 403         struct sigaction act;
 404         char *sender = NULL;
 405         struct queue queue;
 406         int i, ch;
 407         int nodot = 0, showq = 0, queue_only = 0;
 408         int recp_from_header = 0;
 409
 410         set_username();
 411
 412         /*
 413          * We never run as root.  If called by root, drop permissions
 414          * to the mail user.
 415          */
 416         if (geteuid() == 0 || getuid() == 0) {
 417                 struct passwd *pw;
 418
 419                 pw = getpwnam(DMA_ROOT_USER);
 420                 if (pw == NULL)
 421                         err(1, "cannot drop root privileges");
 422
 423                 if (setuid(pw->pw_uid) != 0)
 424                         err(1, "cannot drop root privileges");
 425
 426                 if (geteuid() == 0 || getuid() == 0)
 427                         errx(1, "cannot drop root privileges");
 428         }
 429
 430         atexit(deltmp);
 431         init_random();
 432
 433         bzero(&queue, sizeof(queue));
 434         LIST_INIT(&queue.queue);
 435
 436         if (strcmp(argv[0], "mailq") == 0) {
 437                 argv++; argc--;
 438                 showq = 1;
 439                 if (argc != 0)
 440                         errx(1, "invalid arguments");
 441                 goto skipopts;
 442         }
 443
 444         opterr = 0;
 445         while ((ch = getopt(argc, argv, ":A:b:B:C:d:Df:F:h:iL:N:no:O:q:r:R:tUV:vX:")) != -1) {
 446                 switch (ch) {
 447                 case 'A':
 448                         /* -AX is being ignored, except for -A{c,m} */
 449                         if (optarg[0] == 'c' || optarg[0] == 'm') {
 450                                 break;
 451                         }
 452                         /* else FALLTRHOUGH */
 453                 case 'b':
 454                         /* -bX is being ignored, except for -bp */
 455                         if (optarg[0] == 'p') {
 456                                 showq = 1;
 457                                 break;
 458                         } else if (optarg[0] == 'q') {
 459                                 queue_only = 1;
 460                                 break;
 461                         }
 462                         /* else FALLTRHOUGH */
 463                 case 'D':
 464                         daemonize = 0;
 465                         break;
 466                 case 'L':
 467                         logident_base = optarg;
 468                         break;
 469                 case 'f':
 470                 case 'r':
 471                         sender = optarg;
 472                         break;
 473
 474                 case 't':
 475                         recp_from_header = 1;
 476                         break;
 477
 478                 case 'o':
 479                         /* -oX is being ignored, except for -oi */
 480                         if (optarg[0] != 'i')
 481                                 break;
 482                         /* else FALLTRHOUGH */
 483                 case 'O':
 484                         break;
 485                 case 'i':
 486                         nodot = 1;
 487                         break;
 488
 489                 case 'q':
 490                         /* Don't let getopt slup up other arguments */
 491                         if (optarg && *optarg == '-')
 492                                 optind--;
 493                         doqueue = 1;
 494                         break;
 495
 496                 /* Ignored options */
 497                 case 'B':
 498                 case 'C':
 499                 case 'd':
 500                 case 'F':
 501                 case 'h':
 502                 case 'N':
 503                 case 'n':
 504                 case 'R':
 505                 case 'U':
 506                 case 'V':
 507                 case 'v':
 508                 case 'X':
 509                         break;
 510
 511                 case ':':
 512                         if (optopt == 'q') {
 513                                 doqueue = 1;
 514                                 break;
 515                         }
 516                         /* FALLTHROUGH */
 517
 518                 default:
 519                         fprintf(stderr, "invalid argument: `-%c'\n", optopt);
 520                         exit(1);
 521                 }
 522         }
 523         argc -= optind;
 524         argv += optind;
 525         opterr = 1;
 526
 527         if (argc != 0 && (showq || doqueue))
 528                 errx(1, "sending mail and queue operations are mutually exclusive");
 529
 530         if (showq + doqueue > 1)
 531                 errx(1, "conflicting queue operations");
 532
 533 skipopts:
 534         if (logident_base == NULL)
 535                 logident_base = "dma";
 536         setlogident(NULL);
 537
 538         act.sa_handler = sighup_handler;
 539         act.sa_flags = 0;
 540         sigemptyset(&act.sa_mask);
 541         if (sigaction(SIGHUP, &act, NULL) != 0)
 542                 syslog(LOG_WARNING, "can not set signal handler: %m");
 543
 544         parse_conf(CONF_PATH "/dma.conf");
 545
 546         if (config.authpath != NULL)
 547                 parse_authfile(config.authpath);
 548
 549         if (showq) {
 550                 if (load_queue(&queue) < 0)
 551                         errlog(1, "can not load queue");
 552                 show_queue(&queue);
 553                 return (0);
 554         }
 555
 556         if (doqueue) {
 557                 if (load_queue(&queue) < 0)
 558                         errlog(1, "can not load queue");
 559                 run_queue(&queue);
 560                 return (0);
 561         }
 562
 563         if (read_aliases() != 0)
 564                 errlog(1, "can not read aliases file `%s'", config.aliases);
 565
 566         if ((sender = set_from(&queue, sender)) == NULL)
 567                 errlog(1, NULL);
 568
 569         if (newspoolf(&queue) != 0)
 570                 errlog(1, "can not create temp file");
 571
 572         setlogident("%s", queue.id);
 573
 574         for (i = 0; i < argc; i++) {
 575                 if (add_recp(&queue, argv[i], EXPAND_WILDCARD) != 0)
 576                         errlogx(1, "invalid recipient `%s'", argv[i]);
 577         }
 578
 579         if (LIST_EMPTY(&queue.queue) && !recp_from_header)
 580                 errlogx(1, "no recipients");
 581
 582         if (readmail(&queue, nodot, recp_from_header) != 0)
 583                 errlog(1, "can not read mail");
 584
 585         if (LIST_EMPTY(&queue.queue))
 586                 errlogx(1, "no recipients");
 587
 588         if (linkspool(&queue) != 0)
 589                 errlog(1, "can not create spools");
 590
 591         /* From here on the mail is safe. */
 592
 593         if (config.features & DEFER || queue_only)
 594                 return (0);
 595
 596         run_queue(&queue);
 597
 598         /* NOTREACHED */
 599         return (0);
 600 }