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 "dfcompat.h"
37
38 #include <sys/param.h>
39 #include <sys/types.h>
40 #include <sys/queue.h>
41 #include <sys/stat.h>
42 #include <sys/time.h>
43 #include <sys/wait.h>
44
45 #include <dirent.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <inttypes.h>
50 #include <libgen.h>
51 #include <paths.h>
52 #include <pwd.h>
53 #include <signal.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <syslog.h>
59 #include <unistd.h>
60
61 #include "dma.h"
62
63 extern int yyparse(void);
64 extern FILE *yyin;
65
66 static void deliver(struct qitem *);
67
68 struct aliases aliases = LIST_HEAD_INITIALIZER(aliases);
69 struct strlist tmpfs = SLIST_HEAD_INITIALIZER(tmpfs);
70 struct authusers authusers = LIST_HEAD_INITIALIZER(authusers);
71 char username[USERNAME_SIZE];
72 uid_t useruid;
73 const char *logident_base;
74 char errmsg[ERRMSG_SIZE];
75
76 static int daemonize = 1;
77 static int doqueue = 0;
78
79 struct config config = {
80 .smarthost = NULL,
81 .port = 25,
82 .aliases = "/etc/aliases",
83 .spooldir = "/var/spool/dma",
84 .authpath = NULL,
85 .certfile = NULL,
86 .features = 0,
87 .mailname = NULL,
88 .masquerade_host = NULL,
89 .masquerade_user = NULL,
90 .fingerprint = NULL,
91 };
92
93
94 static void
sighup_handler(int signo)95 sighup_handler(int signo)
96 {
97 (void)signo; /* so that gcc doesn't complain */
98 }
99
100 static char *
set_from(struct queue * queue,const char * osender)101 set_from(struct queue *queue, const char *osender)
102 {
103 const char *addr;
104 char *sender;
105
106 if (config.masquerade_user) {
107 addr = config.masquerade_user;
108 } else if (osender) {
109 addr = osender;
110 } else if (getenv("EMAIL") != NULL) {
111 addr = getenv("EMAIL");
112 } else {
113 addr = username;
114 }
115
116 if (!strchr(addr, '@')) {
117 const char *from_host = hostname();
118
119 if (config.masquerade_host)
120 from_host = config.masquerade_host;
121
122 if (asprintf(&sender, "%s@%s", addr, from_host) <= 0)
123 return (NULL);
124 } else {
125 sender = strdup(addr);
126 if (sender == NULL)
127 return (NULL);
128 }
129
130 if (strchr(sender, '\n') != NULL) {
131 errno = EINVAL;
132 return (NULL);
133 }
134
135 queue->sender = sender;
136 return (sender);
137 }
138
139 static int
read_aliases(void)140 read_aliases(void)
141 {
142 yyin = fopen(config.aliases, "r");
143 if (yyin == NULL) {
144 /*
145 * Non-existing aliases file is not a fatal error
146 */
147 if (errno == ENOENT)
148 return (0);
149 /* Other problems are. */
150 return (-1);
151 }
152 if (yyparse())
153 return (-1); /* fatal error, probably malloc() */
154 fclose(yyin);
155 return (0);
156 }
157
158 static int
do_alias(struct queue * queue,const char * addr)159 do_alias(struct queue *queue, const char *addr)
160 {
161 struct alias *al;
162 struct stritem *sit;
163 int aliased = 0;
164
165 LIST_FOREACH(al, &aliases, next) {
166 if (strcmp(al->alias, addr) != 0)
167 continue;
168 SLIST_FOREACH(sit, &al->dests, next) {
169 if (add_recp(queue, sit->str, EXPAND_ADDR) != 0)
170 return (-1);
171 }
172 aliased = 1;
173 }
174
175 return (aliased);
176 }
177
178 int
add_recp(struct queue * queue,const char * str,int expand)179 add_recp(struct queue *queue, const char *str, int expand)
180 {
181 struct qitem *it, *tit;
182 struct passwd *pw;
183 char *host;
184 int aliased = 0;
185
186 it = calloc(1, sizeof(*it));
187 if (it == NULL)
188 return (-1);
189 it->addr = strdup(str);
190 if (it->addr == NULL)
191 return (-1);
192
193 it->sender = queue->sender;
194 host = strrchr(it->addr, '@');
195 if (host != NULL &&
196 (strcmp(host + 1, hostname()) == 0 ||
197 strcmp(host + 1, "localhost") == 0)) {
198 *host = 0;
199 }
200 LIST_FOREACH(tit, &queue->queue, next) {
201 /* weed out duplicate dests */
202 if (strcmp(tit->addr, it->addr) == 0) {
203 free(it->addr);
204 free(it);
205 return (0);
206 }
207 }
208 LIST_INSERT_HEAD(&queue->queue, it, next);
209
210 /**
211 * Do local delivery if there is no @.
212 * Do not do local delivery when NULLCLIENT is set.
213 */
214 if (strrchr(it->addr, '@') == NULL && (config.features & NULLCLIENT) == 0) {
215 it->remote = 0;
216 if (expand) {
217 aliased = do_alias(queue, it->addr);
218 if (!aliased && expand == EXPAND_WILDCARD)
219 aliased = do_alias(queue, "*");
220 if (aliased < 0)
221 return (-1);
222 if (aliased) {
223 LIST_REMOVE(it, next);
224 } else {
225 /* Local destination, check */
226 pw = getpwnam(it->addr);
227 if (pw == NULL)
228 goto out;
229 /* XXX read .forward */
230 endpwent();
231 }
232 }
233 } else {
234 it->remote = 1;
235 }
236
237 return (0);
238
239 out:
240 free(it->addr);
241 free(it);
242 return (-1);
243 }
244
245 static struct qitem *
go_background(struct queue * queue)246 go_background(struct queue *queue)
247 {
248 struct sigaction sa;
249 struct qitem *it;
250 pid_t pid;
251
252 if (daemonize && daemon(0, 0) != 0) {
253 syslog(LOG_ERR, "can not daemonize: %m");
254 exit(EX_OSERR);
255 }
256 daemonize = 0;
257
258 bzero(&sa, sizeof(sa));
259 sa.sa_handler = SIG_IGN;
260 sigaction(SIGCHLD, &sa, NULL);
261
262 LIST_FOREACH(it, &queue->queue, next) {
263 /* No need to fork for the last dest */
264 if (LIST_NEXT(it, next) == NULL)
265 goto retit;
266
267 pid = fork();
268 switch (pid) {
269 case -1:
270 syslog(LOG_ERR, "can not fork: %m");
271 exit(EX_OSERR);
272 break;
273
274 case 0:
275 /*
276 * Child:
277 *
278 * return and deliver mail
279 */
280 retit:
281 /*
282 * If necessary, acquire the queue and * mail files.
283 * If this fails, we probably were raced by another
284 * process. It is okay to be raced if we're supposed
285 * to flush the queue.
286 */
287 setlogident("%s", it->queueid);
288 switch (acquirespool(it)) {
289 case 0:
290 break;
291 case 1:
292 if (doqueue)
293 exit(EX_OK);
294 syslog(LOG_WARNING, "could not lock queue file");
295 exit(EX_SOFTWARE);
296 default:
297 exit(EX_SOFTWARE);
298 }
299 dropspool(queue, it);
300 return (it);
301
302 default:
303 /*
304 * Parent:
305 *
306 * fork next child
307 */
308 break;
309 }
310 }
311
312 syslog(LOG_CRIT, "reached dead code");
313 exit(EX_SOFTWARE);
314 }
315
316 static void
deliver(struct qitem * it)317 deliver(struct qitem *it)
318 {
319 int error;
320 unsigned int backoff = MIN_RETRY, slept;
321 struct timeval now;
322 struct stat st;
323
324 snprintf(errmsg, sizeof(errmsg), "unknown bounce reason");
325
326 retry:
327 syslog(LOG_INFO, "<%s> trying delivery", it->addr);
328
329 if (it->remote)
330 error = deliver_remote(it);
331 else
332 error = deliver_local(it);
333
334 switch (error) {
335 case 0:
336 syslog(LOG_INFO, "<%s> delivery successful", it->addr);
337 delqueue(it);
338 exit(EX_OK);
339
340 case 1:
341 if (stat(it->queuefn, &st) != 0) {
342 syslog(LOG_ERR, "lost queue file `%s'", it->queuefn);
343 exit(EX_SOFTWARE);
344 }
345 if (gettimeofday(&now, NULL) == 0 &&
346 (now.tv_sec - st.st_mtim.tv_sec > MAX_TIMEOUT)) {
347 snprintf(errmsg, sizeof(errmsg),
348 "Could not deliver for the last %d seconds. Giving up.",
349 MAX_TIMEOUT);
350 goto bounce;
351 }
352 for (slept = 0; slept < backoff;) {
353 slept += SLEEP_TIMEOUT - sleep(SLEEP_TIMEOUT);
354 if (flushqueue_since(slept)) {
355 backoff = MIN_RETRY;
356 goto retry;
357 }
358 }
359 if (slept >= backoff) {
360 /* pick the next backoff between [1.5, 2.5) times backoff */
361 backoff = backoff + backoff / 2 + random() % backoff;
362 if (backoff > MAX_RETRY)
363 backoff = MAX_RETRY;
364 }
365 goto retry;
366
367 case -1:
368 default:
369 break;
370 }
371
372 bounce:
373 bounce(it, errmsg);
374 /* NOTREACHED */
375 }
376
377 void
run_queue(struct queue * queue)378 run_queue(struct queue *queue)
379 {
380 struct qitem *it;
381
382 if (LIST_EMPTY(&queue->queue))
383 return;
384
385 it = go_background(queue);
386 deliver(it);
387 /* NOTREACHED */
388 }
389
390 static void
show_queue(struct queue * queue)391 show_queue(struct queue *queue)
392 {
393 struct qitem *it;
394 int locked = 0; /* XXX */
395
396 if (LIST_EMPTY(&queue->queue)) {
397 printf("Mail queue is empty\n");
398 return;
399 }
400
401 LIST_FOREACH(it, &queue->queue, next) {
402 printf("ID\t: %s%s\n"
403 "From\t: %s\n"
404 "To\t: %s\n",
405 it->queueid,
406 locked ? "*" : "",
407 it->sender, it->addr);
408
409 if (LIST_NEXT(it, next) != NULL)
410 printf("--\n");
411 }
412 }
413
414 /*
415 * TODO:
416 *
417 * - alias processing
418 * - use group permissions
419 * - proper sysexit codes
420 */
421
422 int
main(int argc,char ** argv)423 main(int argc, char **argv)
424 {
425 struct sigaction act;
426 char *sender = NULL;
427 char *own_name = NULL;
428 struct queue queue;
429 int i, ch;
430 int nodot = 0, showq = 0, queue_only = 0, newaliases = 0;
431 int recp_from_header = 0;
432
433 set_username();
434
435 /*
436 * We never run as root. If called by root, drop permissions
437 * to the mail user.
438 */
439 if (geteuid() == 0 || getuid() == 0) {
440 struct passwd *pw;
441
442 errno = 0;
443 pw = getpwnam(DMA_ROOT_USER);
444 if (pw == NULL) {
445 if (errno == 0)
446 errx(EX_CONFIG, "user '%s' not found", DMA_ROOT_USER);
447 else
448 err(EX_OSERR, "cannot drop root privileges");
449 }
450
451 if (setuid(pw->pw_uid) != 0)
452 err(EX_OSERR, "cannot drop root privileges");
453
454 if (geteuid() == 0 || getuid() == 0)
455 errx(EX_OSERR, "cannot drop root privileges");
456 }
457
458 atexit(deltmp);
459 init_random();
460
461 bzero(&queue, sizeof(queue));
462 LIST_INIT(&queue.queue);
463
464 own_name = basename(argv[0]);
465
466 if (strcmp(own_name, "mailq") == 0) {
467 argv++; argc--;
468 showq = 1;
469 if (argc != 0 && strcmp(argv[0], "-Ac") != 0)
470 errx(EX_USAGE, "invalid arguments");
471 goto skipopts;
472 } else if (strcmp(own_name, "newaliases") == 0) {
473 newaliases = 1;
474 goto skipopts;
475 } else if (strcmp(own_name, "hoststat") == 0 ||
476 strcmp(own_name, "purgestat") == 0) {
477 exit(EX_OK);
478 }
479
480 opterr = 0;
481 while ((ch = getopt(argc, argv, ":A:b:B:C:d:Df:F:h:iL:N:no:O:q:r:R:tUV:vX:")) != -1) {
482 switch (ch) {
483 case 'A':
484 /* -AX is being ignored, except for -A{c,m} */
485 if (optarg[0] == 'c' || optarg[0] == 'm') {
486 break;
487 }
488 /* Else FALLTHROUGH */
489 case 'b':
490 /* -bX is being ignored, except for -bp */
491 if (optarg[0] == 'p') {
492 showq = 1;
493 break;
494 } else if (optarg[0] == 'q') {
495 queue_only = 1;
496 break;
497 }
498 /* Else FALLTHROUGH */
499 case 'D':
500 daemonize = 0;
501 break;
502 case 'L':
503 logident_base = optarg;
504 break;
505 case 'f':
506 case 'r':
507 sender = optarg;
508 break;
509
510 case 't':
511 recp_from_header = 1;
512 break;
513
514 case 'o':
515 /* -oX is being ignored, except for -oi */
516 if (optarg[0] != 'i')
517 break;
518 /* Else FALLTHROUGH */
519 case 'i':
520 nodot = 1;
521 break;
522
523 case 'q':
524 /* Don't let getopt slup up other arguments */
525 if (optarg && *optarg == '-')
526 optind--;
527 doqueue = 1;
528 break;
529
530 /* Ignored options */
531 case 'B':
532 case 'C':
533 case 'd':
534 case 'F':
535 case 'h':
536 case 'N':
537 case 'n':
538 case 'O':
539 case 'R':
540 case 'U':
541 case 'V':
542 case 'v':
543 case 'X':
544 break;
545
546 case ':':
547 if (optopt == 'q') {
548 doqueue = 1;
549 break;
550 }
551 /* Else FALLTHROUGH */
552
553 default:
554 fprintf(stderr, "invalid argument: `-%c'\n", optopt);
555 exit(EX_USAGE);
556 }
557 }
558 argc -= optind;
559 argv += optind;
560 opterr = 1;
561
562 if (argc != 0 && (showq || doqueue))
563 errx(EX_USAGE, "sending mail and queue operations are mutually exclusive");
564
565 if (showq + doqueue > 1)
566 errx(EX_USAGE, "conflicting queue operations");
567
568 skipopts:
569 if (logident_base == NULL)
570 logident_base = "dma";
571 setlogident(NULL);
572
573 act.sa_handler = sighup_handler;
574 act.sa_flags = 0;
575 sigemptyset(&act.sa_mask);
576 if (sigaction(SIGHUP, &act, NULL) != 0)
577 syslog(LOG_WARNING, "can not set signal handler: %m");
578
579 parse_conf(CONF_PATH "/dma.conf");
580
581 if (config.authpath != NULL)
582 parse_authfile(config.authpath);
583
584 if (showq) {
585 if (load_queue(&queue) < 0)
586 errlog(EX_NOINPUT, "can not load queue");
587 show_queue(&queue);
588 return (0);
589 }
590
591 if (doqueue) {
592 flushqueue_signal();
593 if (load_queue(&queue) < 0)
594 errlog(EX_NOINPUT, "can not load queue");
595 run_queue(&queue);
596 return (0);
597 }
598
599 if (read_aliases() != 0)
600 errlog(EX_SOFTWARE, "could not parse aliases file `%s'", config.aliases);
601
602 if (newaliases)
603 return(0);
604
605 if ((sender = set_from(&queue, sender)) == NULL)
606 errlog(EX_SOFTWARE, NULL);
607
608 if (newspoolf(&queue) != 0)
609 errlog(EX_CANTCREAT, "can not create temp file in `%s'", config.spooldir);
610
611 setlogident("%s", queue.id);
612
613 for (i = 0; i < argc; i++) {
614 if (add_recp(&queue, argv[i], EXPAND_WILDCARD) != 0)
615 errlogx(EX_DATAERR, "invalid recipient `%s'", argv[i]);
616 }
617
618 if (LIST_EMPTY(&queue.queue) && !recp_from_header)
619 errlogx(EX_NOINPUT, "no recipients");
620
621 if (readmail(&queue, nodot, recp_from_header) != 0)
622 errlog(EX_NOINPUT, "can not read mail");
623
624 if (LIST_EMPTY(&queue.queue))
625 errlogx(EX_NOINPUT, "no recipients");
626
627 if (linkspool(&queue) != 0)
628 errlog(EX_CANTCREAT, "can not create spools");
629
630 /* From here on the mail is safe. */
631
632 if (config.features & DEFER || queue_only)
633 return (0);
634
635 run_queue(&queue);
636
637 /* NOTREACHED */
638 return (0);
639 }
640