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
  74 struct config config = {
  75         .smarthost      = NULL,
  76         .port           = 25,
  77         .aliases        = "/etc/aliases",
  78         .spooldir       = "/var/spool/dma",
  79         .authpath       = NULL,
  80         .certfile       = NULL,
  81         .features       = 0,
  82         .mailname       = NULL,
  83         .masquerade_host = NULL,
  84         .masquerade_user = NULL,
  85 };
  86
  87
  88 static void
  89 sighup_handler(int signo)
  90 {
  91         (void)signo;    /* so that gcc doesn't complain */
  92 }
  93
  94 static char *
  95 set_from(struct queue *queue, const char *osender)
  96 {
  97         char *sender;
  98
  99         if (osender) {
 100                 sender = strdup(osender);
 101                 if (sender == NULL)
 102                         return (NULL);
 103         } else if (getenv("EMAIL") != NULL) {
 104                 sender = strdup(getenv("EMAIL"));
 105                 if (sender == NULL)
 106                         return (NULL);
 107         } else {
 108                 const char *from_user = username;
 109                 const char *from_host = hostname();
 110
 111                 if (config.masquerade_user)
 112                         from_user = config.masquerade_user;
 113                 if (config.masquerade_host)
 114                         from_host = config.masquerade_host;
 115                 if (asprintf(&sender, "%s@%s", from_user, from_host) <= 0)
 116                         return (NULL);
 117         }
 118
 119         if (strchr(sender, '\n') != NULL) {
 120                 errno = EINVAL;
 121                 return (NULL);
 122         }
 123
 124         queue->sender = sender;
 125         return (sender);
 126 }
 127
 128 static int
 129 read_aliases(void)
 130 {
 131         yyin = fopen(config.aliases, "r");
 132         if (yyin == NULL) {
 133                 /*
 134                  * Non-existing aliases file is not a fatal error
 135                  */
 136                 if (errno == ENOENT)
 137                         return (0);
 138                 /* Other problems are. */
 139                 return (-1);
 140         }
 141         if (yyparse())
 142                 return (-1);    /* fatal error, probably malloc() */
 143         fclose(yyin);
 144         return (0);
 145 }
 146
 147 int
 148 add_recp(struct queue *queue, const char *str, int expand)
 149 {
 150         struct qitem *it, *tit;
 151         struct stritem *sit;
 152         struct alias *al;
 153         struct passwd *pw;
 154         char *host;
 155         int aliased = 0;
 156
 157         it = calloc(1, sizeof(*it));
 158         if (it == NULL)
 159                 return (-1);
 160         it->addr = strdup(str);
 161         if (it->addr == NULL)
 162                 return (-1);
 163
 164         it->sender = queue->sender;
 165         host = strrchr(it->addr, '@');
 166         if (host != NULL &&
 167             (strcmp(host + 1, hostname()) == 0 ||
 168              strcmp(host + 1, "localhost") == 0)) {
 169                 *host = 0;
 170         }
 171         LIST_FOREACH(tit, &queue->queue, next) {
 172                 /* weed out duplicate dests */
 173                 if (strcmp(tit->addr, it->addr) == 0) {
 174                         free(it->addr);
 175                         free(it);
 176                         return (0);
 177                 }
 178         }
 179         LIST_INSERT_HEAD(&queue->queue, it, next);
 180         if (strrchr(it->addr, '@') == NULL) {
 181                 it->remote = 0;
 182                 if (expand) {
 183                         LIST_FOREACH(al, &aliases, next) {
 184                                 if (strcmp(al->alias, it->addr) != 0)
 185                                         continue;
 186                                 SLIST_FOREACH(sit, &al->dests, next) {
 187                                         if (add_recp(queue, sit->str, 1) != 0)
 188                                                 return (-1);
 189                                 }
 190                                 aliased = 1;
 191                         }
 192                         if (aliased) {
 193                                 LIST_REMOVE(it, next);
 194                         } else {
 195                                 /* Local destination, check */
 196                                 pw = getpwnam(it->addr);
 197                                 if (pw == NULL)
 198                                         goto out;
 199                                 /* XXX read .forward */
 200                                 endpwent();
 201                         }
 202                 }
 203         } else {
 204                 it->remote = 1;
 205         }
 206
 207         return (0);
 208
 209 out:
 210         free(it->addr);
 211         free(it);
 212         return (-1);
 213 }
 214
 215 static struct qitem *
 216 go_background(struct queue *queue)
 217 {
 218         struct sigaction sa;
 219         struct qitem *it;
 220         pid_t pid;
 221
 222         if (daemonize && daemon(0, 0) != 0) {
 223                 syslog(LOG_ERR, "can not daemonize: %m");
 224                 exit(1);
 225         }
 226         daemonize = 0;
 227
 228         bzero(&sa, sizeof(sa));
 229         sa.sa_handler = SIG_IGN;
 230         sigaction(SIGCHLD, &sa, NULL);
 231
 232         LIST_FOREACH(it, &queue->queue, next) {
 233                 /* No need to fork for the last dest */
 234                 if (LIST_NEXT(it, next) == NULL)
 235                         goto retit;
 236
 237                 pid = fork();
 238                 switch (pid) {
 239                 case -1:
 240                         syslog(LOG_ERR, "can not fork: %m");
 241                         exit(1);
 242                         break;
 243
 244                 case 0:
 245                         /*
 246                          * Child:
 247                          *
 248                          * return and deliver mail
 249                          */
 250 retit:
 251                         /*
 252                          * If necessary, acquire the queue and * mail files.
 253                          * If this fails, we probably were raced by another
 254                          * process.
 255                          */
 256                         setlogident("%s", it->queueid);
 257                         if (acquirespool(it) < 0)
 258                                 exit(1);
 259                         dropspool(queue, it);
 260                         return (it);
 261
 262                 default:
 263                         /*
 264                          * Parent:
 265                          *
 266                          * fork next child
 267                          */
 268                         break;
 269                 }
 270         }
 271
 272         syslog(LOG_CRIT, "reached dead code");
 273         exit(1);
 274 }
 275
 276 static void
 277 deliver(struct qitem *it)
 278 {
 279         int error;
 280         unsigned int backoff = MIN_RETRY;
 281         struct timeval now;
 282         struct stat st;
 283
 284         snprintf(errmsg, sizeof(errmsg), "unknown bounce reason");
 285
 286 retry:
 287         syslog(LOG_INFO, "trying delivery");
 288
 289         if (it->remote)
 290                 error = deliver_remote(it);
 291         else
 292                 error = deliver_local(it);
 293
 294         switch (error) {
 295         case 0:
 296                 delqueue(it);
 297                 syslog(LOG_INFO, "delivery successful");
 298                 exit(0);
 299
 300         case 1:
 301                 if (stat(it->queuefn, &st) != 0) {
 302                         syslog(LOG_ERR, "lost queue file `%s'", it->queuefn);
 303                         exit(1);
 304                 }
 305                 if (gettimeofday(&now, NULL) == 0 &&
 306                     (now.tv_sec - st.st_mtim.tv_sec > MAX_TIMEOUT)) {
 307                         snprintf(errmsg, sizeof(errmsg),
 308                                  "Could not deliver for the last %d seconds. Giving up.",
 309                                  MAX_TIMEOUT);
 310                         goto bounce;
 311                 }
 312                 if (sleep(backoff) == 0) {
 313                         /* pick the next backoff between [1.5, 2.5) times backoff */
 314                         backoff = backoff + backoff / 2 + random() % backoff;
 315                         if (backoff > MAX_RETRY)
 316                                 backoff = MAX_RETRY;
 317                 }
 318                 goto retry;
 319
 320         case -1:
 321         default:
 322                 break;
 323         }
 324
 325 bounce:
 326         bounce(it, errmsg);
 327         /* NOTREACHED */
 328 }
 329
 330 void
 331 run_queue(struct queue *queue)
 332 {
 333         struct qitem *it;
 334
 335         if (LIST_EMPTY(&queue->queue))
 336                 return;
 337
 338         it = go_background(queue);
 339         deliver(it);
 340         /* NOTREACHED */
 341 }
 342
 343 static void
 344 show_queue(struct queue *queue)
 345 {
 346         struct qitem *it;
 347         int locked = 0; /* XXX */
 348
 349         if (LIST_EMPTY(&queue->queue)) {
 350                 printf("Mail queue is empty\n");
 351                 return;
 352         }
 353
 354         LIST_FOREACH(it, &queue->queue, next) {
 355                 printf("ID\t: %s%s\n"
 356                        "From\t: %s\n"
 357                        "To\t: %s\n",
 358                        it->queueid,
 359                        locked ? "*" : "",
 360                        it->sender, it->addr);
 361
 362                 if (LIST_NEXT(it, next) != NULL)
 363                         printf("--\n");
 364         }
 365 }
 366
 367 /*
 368  * TODO:
 369  *
 370  * - alias processing
 371  * - use group permissions
 372  * - proper sysexit codes
 373  */
 374
 375 int
 376 main(int argc, char **argv)
 377 {
 378         struct sigaction act;
 379         char *sender = NULL;
 380         struct queue queue;
 381         int i, ch;
 382         int nodot = 0, doqueue = 0, showq = 0, queue_only = 0;
 383         int recp_from_header = 0;
 384
 385         set_username();
 386
 387         /*
 388          * We never run as root.  If called by root, drop permissions
 389          * to the mail user.
 390          */
 391         if (geteuid() == 0 || getuid() == 0) {
 392                 struct passwd *pw;
 393
 394                 pw = getpwnam(DMA_ROOT_USER);
 395                 if (pw == NULL)
 396                         err(1, "cannot drop root privileges");
 397
 398                 if (setuid(pw->pw_uid) != 0)
 399                         err(1, "cannot drop root privileges");
 400
 401                 if (geteuid() == 0 || getuid() == 0)
 402                         errx(1, "cannot drop root privileges");
 403         }
 404
 405         atexit(deltmp);
 406         init_random();
 407
 408         bzero(&queue, sizeof(queue));
 409         LIST_INIT(&queue.queue);
 410
 411         if (strcmp(argv[0], "mailq") == 0) {
 412                 argv++; argc--;
 413                 showq = 1;
 414                 if (argc != 0)
 415                         errx(1, "invalid arguments");
 416                 goto skipopts;
 417         }
 418
 419         opterr = 0;
 420         while ((ch = getopt(argc, argv, ":A:b:B:C:d:Df:F:h:iL:N:no:O:q:r:R:tUV:vX:")) != -1) {
 421                 switch (ch) {
 422                 case 'A':
 423                         /* -AX is being ignored, except for -A{c,m} */
 424                         if (optarg[0] == 'c' || optarg[0] == 'm') {
 425                                 break;
 426                         }
 427                         /* else FALLTRHOUGH */
 428                 case 'b':
 429                         /* -bX is being ignored, except for -bp */
 430                         if (optarg[0] == 'p') {
 431                                 showq = 1;
 432                                 break;
 433                         } else if (optarg[0] == 'q') {
 434                                 queue_only = 1;
 435                                 break;
 436                         }
 437                         /* else FALLTRHOUGH */
 438                 case 'D':
 439                         daemonize = 0;
 440                         break;
 441                 case 'L':
 442                         logident_base = optarg;
 443                         break;
 444                 case 'f':
 445                 case 'r':
 446                         sender = optarg;
 447                         break;
 448
 449                 case 't':
 450                         recp_from_header = 1;
 451                         break;
 452
 453                 case 'o':
 454                         /* -oX is being ignored, except for -oi */
 455                         if (optarg[0] != 'i')
 456                                 break;
 457                         /* else FALLTRHOUGH */
 458                 case 'O':
 459                         break;
 460                 case 'i':
 461                         nodot = 1;
 462                         break;
 463
 464                 case 'q':
 465                         doqueue = 1;
 466                         break;
 467
 468                 /* Ignored options */
 469                 case 'B':
 470                 case 'C':
 471                 case 'd':
 472                 case 'F':
 473                 case 'h':
 474                 case 'N':
 475                 case 'n':
 476                 case 'R':
 477                 case 'U':
 478                 case 'V':
 479                 case 'v':
 480                 case 'X':
 481                         break;
 482
 483                 case ':':
 484                         if (optopt == 'q') {
 485                                 doqueue = 1;
 486                                 break;
 487                         }
 488                         /* FALLTHROUGH */
 489
 490                 default:
 491                         fprintf(stderr, "invalid argument: `-%c'\n", optopt);
 492                         exit(1);
 493                 }
 494         }
 495         argc -= optind;
 496         argv += optind;
 497         opterr = 1;
 498
 499         if (argc != 0 && (showq || doqueue))
 500                 errx(1, "sending mail and queue operations are mutually exclusive");
 501
 502         if (showq + doqueue > 1)
 503                 errx(1, "conflicting queue operations");
 504
 505 skipopts:
 506         if (logident_base == NULL)
 507                 logident_base = "dma";
 508         setlogident(NULL);
 509
 510         act.sa_handler = sighup_handler;
 511         act.sa_flags = 0;
 512         sigemptyset(&act.sa_mask);
 513         if (sigaction(SIGHUP, &act, NULL) != 0)
 514                 syslog(LOG_WARNING, "can not set signal handler: %m");
 515
 516         parse_conf(CONF_PATH "/dma.conf");
 517
 518         if (config.authpath != NULL)
 519                 parse_authfile(config.authpath);
 520
 521         if (showq) {
 522                 if (load_queue(&queue) < 0)
 523                         errlog(1, "can not load queue");
 524                 show_queue(&queue);
 525                 return (0);
 526         }
 527
 528         if (doqueue) {
 529                 if (load_queue(&queue) < 0)
 530                         errlog(1, "can not load queue");
 531                 run_queue(&queue);
 532                 return (0);
 533         }
 534
 535         if (read_aliases() != 0)
 536                 errlog(1, "can not read aliases file `%s'", config.aliases);
 537
 538         if ((sender = set_from(&queue, sender)) == NULL)
 539                 errlog(1, NULL);
 540
 541         if (newspoolf(&queue) != 0)
 542                 errlog(1, "can not create temp file");
 543
 544         setlogident("%s", queue.id);
 545
 546         for (i = 0; i < argc; i++) {
 547                 if (add_recp(&queue, argv[i], 1) != 0)
 548                         errlogx(1, "invalid recipient `%s'", argv[i]);
 549         }
 550
 551         if (LIST_EMPTY(&queue.queue) && !recp_from_header)
 552                 errlogx(1, "no recipients");
 553
 554         if (readmail(&queue, nodot, recp_from_header) != 0)
 555                 errlog(1, "can not read mail");
 556
 557         if (LIST_EMPTY(&queue.queue))
 558                 errlogx(1, "no recipients");
 559
 560         if (linkspool(&queue) != 0)
 561                 errlog(1, "can not create spools");
 562
 563         /* From here on the mail is safe. */
 564
 565         if (config.features & DEFER || queue_only)
 566                 return (0);
 567
 568         run_queue(&queue);
 569
 570         /* NOTREACHED */
 571         return (0);
 572 }