1 /*
2  * Copyright (c) 2020 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "gmid.h"
18 
19 #include <sys/stat.h>
20 
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <getopt.h>
24 #include <libgen.h>
25 #include <limits.h>
26 #include <pwd.h>
27 #include <signal.h>
28 #include <string.h>
29 
30 static const char	*opts = "6c:D:d:fH:hnP:p:Vvx:";
31 
32 static struct option longopts[] = {
33 	{"help",	no_argument,		NULL,	'h'},
34 	{"version",	no_argument,		NULL,	'V'},
35 	{NULL,		0,			NULL,	0},
36 };
37 
38 struct fcgi fcgi[FCGI_MAX];
39 
40 struct vhosthead hosts;
41 
42 int sock4, sock6;
43 
44 struct imsgbuf logibuf, exibuf, servibuf[PROC_MAX];
45 
46 const char *config_path, *certs_dir, *hostname, *pidfile, *cgi;
47 
48 struct conf conf;
49 
50 struct tls_config *tlsconf;
51 struct tls *ctx;
52 
53 static void
54 dummy_handler(int signo)
55 {
56 	return;
57 }
58 
59 /* wrapper around dirname(3).  dn must be PATH_MAX+1 at least. */
60 static void
61 pdirname(const char *path, char *dn)
62 {
63 	char	 p[PATH_MAX+1];
64 	char	*t;
65 
66 	strlcpy(p, path, sizeof(p));
67 	t = dirname(p);
68 	memmove(dn, t, strlen(t)+1);
69 }
70 
71 static void
72 mkdirs(const char *path, mode_t mode)
73 {
74 	char	dname[PATH_MAX+1];
75 
76 	pdirname(path, dname);
77 	if (!strcmp(dname, "/"))
78 		return;
79 	mkdirs(dname, mode);
80 	if (mkdir(path, mode) != 0 && errno != EEXIST)
81 		fatal("can't mkdir %s: %s", path, strerror(errno));
82 }
83 
84 /* $XDG_DATA_HOME/gmid */
85 char *
86 data_dir(void)
87 {
88 	const char *home, *xdg;
89 	char *t;
90 
91 	if ((xdg = getenv("XDG_DATA_HOME")) == NULL) {
92 		if ((home = getenv("HOME")) == NULL)
93 			errx(1, "XDG_DATA_HOME and HOME both empty");
94 		if (asprintf(&t, "%s/.local/share/gmid", home) == -1)
95 			err(1, "asprintf");
96 	} else {
97 		if (asprintf(&t, "%s/gmid", xdg) == -1)
98 			err(1, "asprintf");
99 	}
100 
101 	mkdirs(t, 0755);
102 	return t;
103 }
104 
105 void
106 load_local_cert(const char *hostname, const char *dir)
107 {
108 	char *cert, *key;
109 	struct vhost *h;
110 
111 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
112 		errx(1, "asprintf");
113 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
114 		errx(1, "asprintf");
115 
116 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
117 		gen_certificate(hostname, cert, key);
118 
119 	h = TAILQ_FIRST(&hosts);
120 	h->cert = cert;
121 	h->key = key;
122 	h->domain = hostname;
123 }
124 
125 void
126 load_vhosts(void)
127 {
128 	struct vhost	*h;
129 	struct location	*l;
130 
131 	TAILQ_FOREACH(h, &hosts, vhosts) {
132 		TAILQ_FOREACH(l, &h->locations, locations) {
133 			if (l->dir == NULL)
134 				continue;
135 			if ((l->dirfd = open(l->dir, O_RDONLY | O_DIRECTORY)) == -1)
136 				fatal("open %s for domain %s", l->dir, h->domain);
137 		}
138 	}
139 }
140 
141 int
142 make_socket(int port, int family)
143 {
144 	int sock, v;
145 	struct sockaddr_in addr4;
146 	struct sockaddr_in6 addr6;
147 	struct sockaddr *addr;
148 	socklen_t len;
149 
150 	switch (family) {
151 	case AF_INET:
152 		memset(&addr4, 0, sizeof(addr4));
153 		addr4.sin_family = family;
154 		addr4.sin_port = htons(port);
155 		addr4.sin_addr.s_addr = INADDR_ANY;
156 		addr = (struct sockaddr*)&addr4;
157 		len = sizeof(addr4);
158 		break;
159 
160 	case AF_INET6:
161 		memset(&addr6, 0, sizeof(addr6));
162 		addr6.sin6_family = AF_INET6;
163 		addr6.sin6_port = htons(port);
164 		addr6.sin6_addr = in6addr_any;
165 		addr = (struct sockaddr*)&addr6;
166 		len = sizeof(addr6);
167 		break;
168 
169 	default:
170 		/* unreachable */
171 		abort();
172 	}
173 
174 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
175 		fatal("socket: %s", strerror(errno));
176 
177 	v = 1;
178 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
179 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
180 
181 	v = 1;
182 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
183 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
184 
185 	mark_nonblock(sock);
186 
187 	if (bind(sock, addr, len) == -1)
188 		fatal("bind: %s", strerror(errno));
189 
190 	if (listen(sock, 16) == -1)
191 		fatal("listen: %s", strerror(errno));
192 
193 	return sock;
194 }
195 
196 void
197 setup_tls(void)
198 {
199 	struct vhost *h;
200 
201 	if ((tlsconf = tls_config_new()) == NULL)
202 		fatal("tls_config_new");
203 
204 	/* optionally accept client certs, but don't try to verify them */
205 	tls_config_verify_client_optional(tlsconf);
206 	tls_config_insecure_noverifycert(tlsconf);
207 
208 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
209 		fatal("tls_config_set_protocols");
210 
211 	if ((ctx = tls_server()) == NULL)
212 		fatal("tls_server failure");
213 
214 	h = TAILQ_FIRST(&hosts);
215 
216 	/* we need to set something, then we can add how many key we want */
217 	if (tls_config_set_keypair_file(tlsconf, h->cert, h->key))
218 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
219 		    h->cert, h->key);
220 
221 	while ((h = TAILQ_NEXT(h, vhosts)) != NULL) {
222 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
223 			fatal("failed to load the keypair (%s, %s)",
224 			    h->cert, h->key);
225 	}
226 
227 	if (tls_configure(ctx, tlsconf) == -1)
228 		fatal("tls_configure: %s", tls_error(ctx));
229 }
230 
231 static int
232 listener_main(struct imsgbuf *ibuf)
233 {
234 	drop_priv();
235 	load_default_mime(&conf.mime);
236 	load_vhosts();
237 	loop(ctx, sock4, sock6, ibuf);
238 	return 0;
239 }
240 
241 void
242 init_config(void)
243 {
244 	TAILQ_INIT(&hosts);
245 
246 	conf.port = 1965;
247 	conf.ipv6 = 0;
248 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
249 
250 	init_mime(&conf.mime);
251 
252 	conf.chroot = NULL;
253 	conf.user = NULL;
254 
255 	conf.prefork = 3;
256 }
257 
258 void
259 free_config(void)
260 {
261 	struct vhost *h, *th;
262 	struct location *l, *tl;
263 	struct envlist *e, *te;
264 	struct alist *a, *ta;
265 	int v, i;
266 
267 	v = conf.verbose;
268 
269 	free(conf.chroot);
270 	free(conf.user);
271 	memset(&conf, 0, sizeof(conf));
272 
273 	conf.verbose = v;
274 
275 	TAILQ_FOREACH_SAFE(h, &hosts, vhosts, th) {
276 		TAILQ_FOREACH_SAFE(l, &h->locations, locations, tl) {
277 			TAILQ_REMOVE(&h->locations, l, locations);
278 
279 			free((char*)l->match);
280 			free((char*)l->lang);
281 			free((char*)l->default_mime);
282 			free((char*)l->index);
283 			free((char*)l->block_fmt);
284 			free((char*)l->dir);
285 
286 			if (l->dirfd != -1)
287 				close(l->dirfd);
288 
289 			free(l);
290 		}
291 
292 		TAILQ_FOREACH_SAFE(e, &h->env, envs, te) {
293 			TAILQ_REMOVE(&h->env, e, envs);
294 
295 			free(e->name);
296 			free(e->value);
297 			free(e);
298 		}
299 
300 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
301 			TAILQ_REMOVE(&h->params, e, envs);
302 
303 			free(e->name);
304 			free(e->value);
305 			free(e);
306 		}
307 
308 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
309 			TAILQ_REMOVE(&h->aliases, a, aliases);
310 
311 			free(a->alias);
312 			free(a);
313 		}
314 
315 		free((char*)h->domain);
316 		free((char*)h->cert);
317 		free((char*)h->key);
318 		free((char*)h->cgi);
319 		free((char*)h->entrypoint);
320 
321 		TAILQ_REMOVE(&hosts, h, vhosts);
322 		free(h);
323 	}
324 
325 	for (i = 0; i < FCGI_MAX; ++i) {
326 		if (fcgi[i].path == NULL && fcgi[i].prog == NULL)
327 			break;
328 		free(fcgi[i].path);
329 		free(fcgi[i].port);
330 		free(fcgi[i].prog);
331 
332 		fcgi[i].path = NULL;
333 		fcgi[i].port = NULL;
334 		fcgi[i].prog = NULL;
335 	}
336 
337 	tls_free(ctx);
338 	tls_config_free(tlsconf);
339 }
340 
341 static int
342 wait_signal(void)
343 {
344 	sigset_t mask;
345 	int signo;
346 
347 	sigemptyset(&mask);
348 	sigaddset(&mask, SIGHUP);
349 	sigaddset(&mask, SIGINT);
350 	sigaddset(&mask, SIGTERM);
351 	sigwait(&mask, &signo);
352 
353 	return signo == SIGHUP;
354 }
355 
356 void
357 drop_priv(void)
358 {
359 	struct passwd *pw = NULL;
360 
361 	if (conf.chroot != NULL && conf.user == NULL)
362 		fatal("can't chroot without an user to switch to after.");
363 
364 	if (conf.user != NULL) {
365 		if ((pw = getpwnam(conf.user)) == NULL)
366 			fatal("can't find user %s", conf.user);
367 	}
368 
369 	if (conf.chroot != NULL) {
370 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
371 			fatal("%s: %s", conf.chroot, strerror(errno));
372 	}
373 
374 	if (pw != NULL) {
375 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
376 			fatal("setresuid(%d): %s", pw->pw_uid,
377 			    strerror(errno));
378 	}
379 
380 	if (getuid() == 0)
381 		log_warn(NULL, "not a good idea to run a network daemon as root");
382 }
383 
384 static void
385 usage(void)
386 {
387 	fprintf(stderr,
388 	    "Version: " GMID_STRING "\n"
389 	    "Usage: %s [-fnv] [-c config] [-D macro=value] [-P pidfile]\n"
390 	    "       %s [-6hVv] [-d certs-dir] [-H hostname] [-p port] [-x cgi] [dir]\n",
391 	    getprogname(),
392 	    getprogname());
393 }
394 
395 static void
396 logger_init(void)
397 {
398 	int p[2];
399 
400 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
401 		err(1, "socketpair");
402 
403 	switch (fork()) {
404 	case -1:
405 		err(1, "fork");
406 	case 0:
407 		signal(SIGHUP, SIG_IGN);
408 		close(p[0]);
409 		setproctitle("logger");
410 		imsg_init(&logibuf, p[1]);
411 		drop_priv();
412 		_exit(logger_main(p[1], &logibuf));
413 	default:
414 		close(p[1]);
415 		imsg_init(&logibuf, p[0]);
416 		return;
417 	}
418 }
419 
420 static int
421 serve(int argc, char **argv, struct imsgbuf *ibuf)
422 {
423 	char		 path[PATH_MAX];
424 	int		 i, p[2];
425 	struct vhost	*h;
426 	struct location	*l;
427 
428 	if (config_path == NULL) {
429 		if (hostname == NULL)
430 			hostname = "localhost";
431 		if (certs_dir == NULL)
432 			certs_dir = data_dir();
433 		load_local_cert(hostname, certs_dir);
434 
435 		h = TAILQ_FIRST(&hosts);
436 		h->domain = "*";
437 
438 		l = TAILQ_FIRST(&h->locations);
439 		l->auto_index = 1;
440 		l->match = "*";
441 
442 		switch (argc) {
443 		case 0:
444 			l->dir = getcwd(path, sizeof(path));
445 			break;
446 		case 1:
447 			l->dir = absolutify_path(argv[0]);
448 			break;
449 		default:
450 			usage();
451 			return 1;
452 		}
453 
454 		log_notice(NULL, "serving %s on port %d", l->dir, conf.port);
455 	}
456 
457 	/* setup tls before dropping privileges: we don't want user
458 	 * to put private certs inside the chroot. */
459 	setup_tls();
460 
461 	for (i = 0; i < conf.prefork; ++i) {
462 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
463 		    PF_UNSPEC, p) == -1)
464 			fatal("socketpair: %s", strerror(errno));
465 
466 		switch (fork()) {
467 		case -1:
468 			fatal("fork: %s", strerror(errno));
469 		case 0:		/* child */
470 			close(p[0]);
471 			imsg_init(&exibuf, p[1]);
472 			setproctitle("server");
473 			_exit(listener_main(&exibuf));
474 		default:
475 			close(p[1]);
476 			imsg_init(&servibuf[i], p[0]);
477 		}
478 	}
479 
480 	setproctitle("executor");
481 	drop_priv();
482 	_exit(executor_main(ibuf));
483 }
484 
485 static int
486 write_pidfile(const char *pidfile)
487 {
488 	struct flock	lock;
489 	int		fd;
490 
491 	if (pidfile == NULL)
492 		return -1;
493 
494 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
495 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
496 
497 	lock.l_start = 0;
498 	lock.l_len = 0;
499 	lock.l_type = F_WRLCK;
500 	lock.l_whence = SEEK_SET;
501 
502 	if (fcntl(fd, F_SETLK, &lock) == -1)
503 		fatal("can't lock %s, gmid is already running?", pidfile);
504 
505 	if (ftruncate(fd, 0) == -1)
506 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
507 
508 	dprintf(fd, "%d\n", getpid());
509 
510 	return fd;
511 }
512 
513 static void
514 setup_configless(int argc, char **argv, const char *cgi)
515 {
516 	struct vhost	*host;
517 	struct location	*loc;
518 
519 	host = xcalloc(1, sizeof(*host));
520 	host->cgi = cgi;
521 	TAILQ_INSERT_HEAD(&hosts, host, vhosts);
522 
523 	loc = xcalloc(1, sizeof(*loc));
524 	loc->fcgi = -1;
525 	TAILQ_INSERT_HEAD(&host->locations, loc, locations);
526 
527 	serve(argc, argv, NULL);
528 
529 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
530 	imsg_flush(&logibuf);
531 }
532 
533 static int
534 parse_portno(const char *p)
535 {
536 	const char *errstr;
537 	int n;
538 
539 	n = strtonum(p, 0, UINT16_MAX, &errstr);
540 	if (errstr != NULL)
541 		yyerror("port number is %s: %s", errstr, p);
542 	return n;
543 }
544 
545 int
546 main(int argc, char **argv)
547 {
548 	struct imsgbuf exibuf;
549 	int ch, conftest = 0, configless = 0;
550 	int pidfd, old_ipv6, old_port;
551 
552 	logger_init();
553 	init_config();
554 
555 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
556 		switch (ch) {
557 		case '6':
558 			conf.ipv6 = 1;
559 			configless = 1;
560 			break;
561 
562 		case 'c':
563 			config_path = absolutify_path(optarg);
564 			break;
565 
566 		case 'D':
567 			if (cmdline_symset(optarg) == -1)
568 				fatal("could not parse macro definition: %s",
569 				    optarg);
570 			break;
571 
572 		case 'd':
573 			certs_dir = optarg;
574 			configless = 1;
575 			break;
576 
577 		case 'f':
578 			conf.foreground = 1;
579 			break;
580 
581 		case 'H':
582 			hostname = optarg;
583 			configless = 1;
584 			break;
585 
586 		case 'h':
587 			usage();
588 			return 0;
589 
590 		case 'n':
591 			conftest = 1;
592 			break;
593 
594 		case 'P':
595 			pidfile = optarg;
596 			break;
597 
598 		case 'p':
599 			conf.port = parse_portno(optarg);
600 			configless = 1;
601 			break;
602 
603 		case 'V':
604 			puts("Version: " GMID_STRING);
605 			return 0;
606 
607 		case 'v':
608 			conf.verbose++;
609 			break;
610 
611 		case 'x':
612 			/* drop the starting / (if any) */
613 			if (*optarg == '/')
614 				optarg++;
615 			cgi = optarg;
616 			configless = 1;
617 			break;
618 
619 		default:
620 			usage();
621 			return 1;
622 		}
623 	}
624 	argc -= optind;
625 	argv += optind;
626 
627 	if (config_path == NULL) {
628 		configless = 1;
629 		conf.foreground = 1;
630 		conf.prefork = 1;
631 		conf.verbose++;
632 	}
633 
634 	if (config_path != NULL && (argc > 0 || configless))
635 		fatal("can't specify options in config mode.");
636 
637 	if (conftest) {
638 		if (config_path == NULL)
639 			fatal("missing configuration");
640 		parse_conf(config_path);
641 		puts("config OK");
642 		return 0;
643 	}
644 
645 	if (!conf.foreground && !configless) {
646 		/* log to syslog */
647 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
648 		imsg_flush(&logibuf);
649 
650 		if (daemon(1, 1) == -1)
651 			fatal("daemon: %s", strerror(errno));
652 	}
653 
654 	if (config_path != NULL)
655 		parse_conf(config_path);
656 
657 	sock4 = make_socket(conf.port, AF_INET);
658 	sock6 = -1;
659 	if (conf.ipv6)
660 		sock6 = make_socket(conf.port, AF_INET6);
661 
662 	signal(SIGPIPE, SIG_IGN);
663 	signal(SIGCHLD, SIG_IGN);
664 
665 	if (configless) {
666 		setup_configless(argc, argv, cgi);
667 		return 0;
668 	}
669 
670 	pidfd = write_pidfile(pidfile);
671 
672 	/*
673 	 * Linux seems to call the event handlers even when we're
674 	 * doing a sigwait.  These dummy handlers are here to avoid
675 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
676 	 */
677 	signal(SIGHUP, dummy_handler);
678 	signal(SIGINT, dummy_handler);
679 	signal(SIGTERM, dummy_handler);
680 
681 	/* wait a sighup and reload the daemon */
682 	for (;;) {
683 		int p[2];
684 
685 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
686 		    PF_UNSPEC, p) == -1)
687 			fatal("socketpair: %s", strerror(errno));
688 
689 		switch (fork()) {
690 		case -1:
691 			fatal("fork: %s", strerror(errno));
692 		case 0:
693 			close(p[0]);
694 			imsg_init(&exibuf, p[1]);
695 			_exit(serve(argc, argv, &exibuf));
696 		}
697 
698 		close(p[1]);
699 		imsg_init(&exibuf, p[0]);
700 
701 		if (!wait_signal())
702 			break;
703 
704 		log_info(NULL, "reloading configuration %s", config_path);
705 
706 		/* close the executor (it'll close the servers too) */
707 		imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
708 		imsg_flush(&exibuf);
709 		close(p[0]);
710 
711 		old_ipv6 = conf.ipv6;
712 		old_port = conf.port;
713 
714 		free_config();
715 		init_config();
716 		parse_conf(config_path);
717 
718 		if (old_port != conf.port) {
719 			close(sock4);
720 			close(sock6);
721 			sock4 = -1;
722 			sock6 = -1;
723 		}
724 
725 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
726 			close(sock6);
727 			sock6 = -1;
728 		}
729 
730 		if (sock4 == -1)
731 			sock4 = make_socket(conf.port, AF_INET);
732 		if (sock6 == -1 && conf.ipv6)
733 			sock6 = make_socket(conf.port, AF_INET6);
734 	}
735 
736 	imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
737 	imsg_flush(&exibuf);
738 
739 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
740 	imsg_flush(&logibuf);
741 
742 	if (pidfd != -1)
743 		close(pidfd);
744 
745 	return 0;
746 }