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, slept;
 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                 for (slept = 0; slept < backoff;) {
 338                         slept += SLEEP_TIMEOUT - sleep(SLEEP_TIMEOUT);
 339                         if (flushqueue_since(slept)) {
 340                                 backoff = MIN_RETRY;
 341                                 goto retry;
 342                         }
 343                 }
 344                 if (slept >= backoff) {
 345                         /* pick the next backoff between [1.5, 2.5) times backoff */
 346                         backoff = backoff + backoff / 2 + random() % backoff;
 347                         if (backoff > MAX_RETRY)
 348                                 backoff = MAX_RETRY;
 349                 }
 350                 goto retry;
 351
 352         case -1:
 353         default:
 354                 break;
 355         }
 356
 357 bounce:
 358         bounce(it, errmsg);
 359         /* NOTREACHED */
 360 }
 361
 362 void
 363 run_queue(struct queue *queue)
 364 {
 365         struct qitem *it;
 366
 367         if (LIST_EMPTY(&queue->queue))
 368                 return;
 369
 370         it = go_background(queue);
 371         deliver(it);
 372         /* NOTREACHED */
 373 }
 374
 375 static void
 376 show_queue(struct queue *queue)
 377 {
 378         struct qitem *it;
 379         int locked = 0; /* XXX */
 380
 381         if (LIST_EMPTY(&queue->queue)) {
 382                 printf("Mail queue is empty\n");
 383                 return;
 384         }
 385
 386         LIST_FOREACH(it, &queue->queue, next) {
 387                 printf("ID\t: %s%s\n"
 388                        "From\t: %s\n"
 389                        "To\t: %s\n",
 390                        it->queueid,
 391                        locked ? "*" : "",
 392                        it->sender, it->addr);
 393
 394                 if (LIST_NEXT(it, next) != NULL)
 395                         printf("--\n");
 396         }
 397 }
 398
 399 /*
 400  * TODO:
 401  *
 402  * - alias processing
 403  * - use group permissions
 404  * - proper sysexit codes
 405  */
 406
 407 int
 408 main(int argc, char **argv)
 409 {
 410         struct sigaction act;
 411         char *sender = NULL;
 412         struct queue queue;
 413         int i, ch;
 414         int nodot = 0, showq = 0, queue_only = 0;
 415         int recp_from_header = 0;
 416
 417         set_username();
 418
 419         /*
 420          * We never run as root.  If called by root, drop permissions
 421          * to the mail user.
 422          */
 423         if (geteuid() == 0 || getuid() == 0) {
 424                 struct passwd *pw;
 425
 426                 errno = 0;
 427                 pw = getpwnam(DMA_ROOT_USER);
 428                 if (pw == NULL) {
 429                         if (errno == 0)
 430                                 errx(1, "user '%s' not found", DMA_ROOT_USER);
 431                         else
 432                                 err(1, "cannot drop root privileges");
 433                 }
 434
 435                 if (setuid(pw->pw_uid) != 0)
 436                         err(1, "cannot drop root privileges");
 437
 438                 if (geteuid() == 0 || getuid() == 0)
 439                         errx(1, "cannot drop root privileges");
 440         }
 441
 442         atexit(deltmp);
 443         init_random();
 444
 445         bzero(&queue, sizeof(queue));
 446         LIST_INIT(&queue.queue);
 447
 448         if (strcmp(argv[0], "mailq") == 0) {
 449                 argv++; argc--;
 450                 showq = 1;
 451                 if (argc != 0)
 452                         errx(1, "invalid arguments");
 453                 goto skipopts;
 454         }
 455
 456         opterr = 0;
 457         while ((ch = getopt(argc, argv, ":A:b:B:C:d:Df:F:h:iL:N:no:O:q:r:R:tUV:vX:")) != -1) {
 458                 switch (ch) {
 459                 case 'A':
 460                         /* -AX is being ignored, except for -A{c,m} */
 461                         if (optarg[0] == 'c' || optarg[0] == 'm') {
 462                                 break;
 463                         }
 464                         /* else FALLTRHOUGH */
 465                 case 'b':
 466                         /* -bX is being ignored, except for -bp */
 467                         if (optarg[0] == 'p') {
 468                                 showq = 1;
 469                                 break;
 470                         } else if (optarg[0] == 'q') {
 471                                 queue_only = 1;
 472                                 break;
 473                         }
 474                         /* else FALLTRHOUGH */
 475                 case 'D':
 476                         daemonize = 0;
 477                         break;
 478                 case 'L':
 479                         logident_base = optarg;
 480                         break;
 481                 case 'f':
 482                 case 'r':
 483                         sender = optarg;
 484                         break;
 485
 486                 case 't':
 487                         recp_from_header = 1;
 488                         break;
 489
 490                 case 'o':
 491                         /* -oX is being ignored, except for -oi */
 492                         if (optarg[0] != 'i')
 493                                 break;
 494                         /* else FALLTRHOUGH */
 495                 case 'O':
 496                         break;
 497                 case 'i':
 498                         nodot = 1;
 499                         break;
 500
 501                 case 'q':
 502                         /* Don't let getopt slup up other arguments */
 503                         if (optarg && *optarg == '-')
 504                                 optind--;
 505                         doqueue = 1;
 506                         break;
 507
 508                 /* Ignored options */
 509                 case 'B':
 510                 case 'C':
 511                 case 'd':
 512                 case 'F':
 513                 case 'h':
 514                 case 'N':
 515                 case 'n':
 516                 case 'R':
 517                 case 'U':
 518                 case 'V':
 519                 case 'v':
 520                 case 'X':
 521                         break;
 522
 523                 case ':':
 524                         if (optopt == 'q') {
 525                                 doqueue = 1;
 526                                 break;
 527                         }
 528                         /* FALLTHROUGH */
 529
 530                 default:
 531                         fprintf(stderr, "invalid argument: `-%c'\n", optopt);
 532                         exit(1);
 533                 }
 534         }
 535         argc -= optind;
 536         argv += optind;
 537         opterr = 1;
 538
 539         if (argc != 0 && (showq || doqueue))
 540                 errx(1, "sending mail and queue operations are mutually exclusive");
 541
 542         if (showq + doqueue > 1)
 543                 errx(1, "conflicting queue operations");
 544
 545 skipopts:
 546         if (logident_base == NULL)
 547                 logident_base = "dma";
 548         setlogident(NULL);
 549
 550         act.sa_handler = sighup_handler;
 551         act.sa_flags = 0;
 552         sigemptyset(&act.sa_mask);
 553         if (sigaction(SIGHUP, &act, NULL) != 0)
 554                 syslog(LOG_WARNING, "can not set signal handler: %m");
 555
 556         parse_conf(CONF_PATH "/dma.conf");
 557
 558         if (config.authpath != NULL)
 559                 parse_authfile(config.authpath);
 560
 561         if (showq) {
 562                 if (load_queue(&queue) < 0)
 563                         errlog(1, "can not load queue");
 564                 show_queue(&queue);
 565                 return (0);
 566         }
 567
 568         if (doqueue) {
 569                 flushqueue_signal();
 570                 if (load_queue(&queue) < 0)
 571                         errlog(1, "can not load queue");
 572                 run_queue(&queue);
 573                 return (0);
 574         }
 575
 576         if (read_aliases() != 0)
 577                 errlog(1, "can not read aliases file `%s'", config.aliases);
 578
 579         if ((sender = set_from(&queue, sender)) == NULL)
 580                 errlog(1, NULL);
 581
 582         if (newspoolf(&queue) != 0)
 583                 errlog(1, "can not create temp file in `%s'", config.spooldir);
 584
 585         setlogident("%s", queue.id);
 586
 587         for (i = 0; i < argc; i++) {
 588                 if (add_recp(&queue, argv[i], EXPAND_WILDCARD) != 0)
 589                         errlogx(1, "invalid recipient `%s'", argv[i]);
 590         }
 591
 592         if (LIST_EMPTY(&queue.queue) && !recp_from_header)
 593                 errlogx(1, "no recipients");
 594
 595         if (readmail(&queue, nodot, recp_from_header) != 0)
 596                 errlog(1, "can not read mail");
 597
 598         if (LIST_EMPTY(&queue.queue))
 599                 errlogx(1, "no recipients");
 600
 601         if (linkspool(&queue) != 0)
 602                 errlog(1, "can not create spools");
 603
 604         /* From here on the mail is safe. */
 605
 606         if (config.features & DEFER || queue_only)
 607                 return (0);
 608
 609         run_queue(&queue);
 610
 611         /* NOTREACHED */
 612         return (0);
 613 }