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: %s", l->dir, h->domain,
137 				    strerror(errno));
138 		}
139 	}
140 }
141 
142 int
143 make_socket(int port, int family)
144 {
145 	int sock, v;
146 	struct sockaddr_in addr4;
147 	struct sockaddr_in6 addr6;
148 	struct sockaddr *addr;
149 	socklen_t len;
150 
151 	switch (family) {
152 	case AF_INET:
153 		memset(&addr4, 0, sizeof(addr4));
154 		addr4.sin_family = family;
155 		addr4.sin_port = htons(port);
156 		addr4.sin_addr.s_addr = INADDR_ANY;
157 		addr = (struct sockaddr*)&addr4;
158 		len = sizeof(addr4);
159 		break;
160 
161 	case AF_INET6:
162 		memset(&addr6, 0, sizeof(addr6));
163 		addr6.sin6_family = AF_INET6;
164 		addr6.sin6_port = htons(port);
165 		addr6.sin6_addr = in6addr_any;
166 		addr = (struct sockaddr*)&addr6;
167 		len = sizeof(addr6);
168 		break;
169 
170 	default:
171 		/* unreachable */
172 		abort();
173 	}
174 
175 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
176 		fatal("socket: %s", strerror(errno));
177 
178 	v = 1;
179 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
180 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
181 
182 	v = 1;
183 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
184 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
185 
186 	mark_nonblock(sock);
187 
188 	if (bind(sock, addr, len) == -1)
189 		fatal("bind: %s", strerror(errno));
190 
191 	if (listen(sock, 16) == -1)
192 		fatal("listen: %s", strerror(errno));
193 
194 	return sock;
195 }
196 
197 static void
198 add_keypair(struct vhost *h)
199 {
200 	if (h->ocsp == NULL) {
201 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
202 			fatal("failed to load the keypair (%s, %s)",
203 			    h->cert, h->key);
204 	} else {
205 		if (tls_config_add_keypair_ocsp_file(tlsconf, h->cert, h->key, h->ocsp) == -1)
206 			fatal("failed to load the keypair (%s, %s, %s)",
207 			    h->cert, h->key, h->ocsp);
208 	}
209 }
210 
211 void
212 setup_tls(void)
213 {
214 	struct vhost *h;
215 
216 	if ((tlsconf = tls_config_new()) == NULL)
217 		fatal("tls_config_new");
218 
219 	/* optionally accept client certs, but don't try to verify them */
220 	tls_config_verify_client_optional(tlsconf);
221 	tls_config_insecure_noverifycert(tlsconf);
222 
223 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
224 		fatal("tls_config_set_protocols");
225 
226 	if ((ctx = tls_server()) == NULL)
227 		fatal("tls_server failure");
228 
229 	h = TAILQ_FIRST(&hosts);
230 
231 	/* we need to set something, then we can add how many key we want */
232 	if (tls_config_set_keypair_file(tlsconf, h->cert, h->key))
233 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
234 		    h->cert, h->key);
235 	if (h->ocsp != NULL &&
236 	    tls_config_set_ocsp_staple_file(tlsconf, h->ocsp) == -1)
237 		fatal("tls_config_set_ocsp_staple_file failed for (%s)",
238 		    h->ocsp);
239 
240 	while ((h = TAILQ_NEXT(h, vhosts)) != NULL)
241 		add_keypair(h);
242 
243 	if (tls_configure(ctx, tlsconf) == -1)
244 		fatal("tls_configure: %s", tls_error(ctx));
245 }
246 
247 static int
248 listener_main(struct imsgbuf *ibuf)
249 {
250 	drop_priv();
251 	load_default_mime(&conf.mime);
252 	load_vhosts();
253 	loop(ctx, sock4, sock6, ibuf);
254 	return 0;
255 }
256 
257 void
258 init_config(void)
259 {
260 	TAILQ_INIT(&hosts);
261 
262 	conf.port = 1965;
263 	conf.ipv6 = 0;
264 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
265 
266 	init_mime(&conf.mime);
267 
268 	conf.chroot = NULL;
269 	conf.user = NULL;
270 
271 	conf.prefork = 3;
272 }
273 
274 void
275 free_config(void)
276 {
277 	struct vhost *h, *th;
278 	struct location *l, *tl;
279 	struct envlist *e, *te;
280 	struct alist *a, *ta;
281 	int v, i;
282 
283 	v = conf.verbose;
284 
285 	free(conf.chroot);
286 	free(conf.user);
287 	memset(&conf, 0, sizeof(conf));
288 
289 	conf.verbose = v;
290 
291 	TAILQ_FOREACH_SAFE(h, &hosts, vhosts, th) {
292 		TAILQ_FOREACH_SAFE(l, &h->locations, locations, tl) {
293 			TAILQ_REMOVE(&h->locations, l, locations);
294 
295 			free((char*)l->match);
296 			free((char*)l->lang);
297 			free((char*)l->default_mime);
298 			free((char*)l->index);
299 			free((char*)l->block_fmt);
300 			free((char*)l->dir);
301 
302 			if (l->dirfd != -1)
303 				close(l->dirfd);
304 
305 			free(l);
306 		}
307 
308 		TAILQ_FOREACH_SAFE(e, &h->env, envs, te) {
309 			TAILQ_REMOVE(&h->env, e, envs);
310 
311 			free(e->name);
312 			free(e->value);
313 			free(e);
314 		}
315 
316 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
317 			TAILQ_REMOVE(&h->params, e, envs);
318 
319 			free(e->name);
320 			free(e->value);
321 			free(e);
322 		}
323 
324 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
325 			TAILQ_REMOVE(&h->aliases, a, aliases);
326 
327 			free(a->alias);
328 			free(a);
329 		}
330 
331 		free((char*)h->domain);
332 		free((char*)h->cert);
333 		free((char*)h->key);
334 		free((char*)h->cgi);
335 		free((char*)h->entrypoint);
336 
337 		TAILQ_REMOVE(&hosts, h, vhosts);
338 		free(h);
339 	}
340 
341 	for (i = 0; i < FCGI_MAX; ++i) {
342 		if (fcgi[i].path == NULL && fcgi[i].prog == NULL)
343 			break;
344 		free(fcgi[i].path);
345 		free(fcgi[i].port);
346 		free(fcgi[i].prog);
347 
348 		fcgi[i].path = NULL;
349 		fcgi[i].port = NULL;
350 		fcgi[i].prog = NULL;
351 	}
352 
353 	tls_free(ctx);
354 	tls_config_free(tlsconf);
355 }
356 
357 static int
358 wait_signal(void)
359 {
360 	sigset_t mask;
361 	int signo;
362 
363 	sigemptyset(&mask);
364 	sigaddset(&mask, SIGHUP);
365 	sigaddset(&mask, SIGINT);
366 	sigaddset(&mask, SIGTERM);
367 	sigwait(&mask, &signo);
368 
369 	return signo == SIGHUP;
370 }
371 
372 void
373 drop_priv(void)
374 {
375 	struct passwd *pw = NULL;
376 
377 	if (conf.chroot != NULL && conf.user == NULL)
378 		fatal("can't chroot without an user to switch to after.");
379 
380 	if (conf.user != NULL) {
381 		if ((pw = getpwnam(conf.user)) == NULL)
382 			fatal("can't find user %s", conf.user);
383 	}
384 
385 	if (conf.chroot != NULL) {
386 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
387 			fatal("%s: %s", conf.chroot, strerror(errno));
388 	}
389 
390 	if (pw != NULL) {
391 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
392 			fatal("setresuid(%d): %s", pw->pw_uid,
393 			    strerror(errno));
394 	}
395 
396 	if (getuid() == 0)
397 		log_warn(NULL, "not a good idea to run a network daemon as root");
398 }
399 
400 static void
401 usage(void)
402 {
403 	fprintf(stderr,
404 	    "Version: " GMID_STRING "\n"
405 	    "Usage: %s [-fnv] [-c config] [-D macro=value] [-P pidfile]\n"
406 	    "       %s [-6hVv] [-d certs-dir] [-H hostname] [-p port] [-x cgi] [dir]\n",
407 	    getprogname(),
408 	    getprogname());
409 }
410 
411 static void
412 logger_init(void)
413 {
414 	int p[2];
415 
416 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
417 		err(1, "socketpair");
418 
419 	switch (fork()) {
420 	case -1:
421 		err(1, "fork");
422 	case 0:
423 		signal(SIGHUP, SIG_IGN);
424 		close(p[0]);
425 		setproctitle("logger");
426 		imsg_init(&logibuf, p[1]);
427 		drop_priv();
428 		_exit(logger_main(p[1], &logibuf));
429 	default:
430 		close(p[1]);
431 		imsg_init(&logibuf, p[0]);
432 		return;
433 	}
434 }
435 
436 static int
437 serve(int argc, char **argv, struct imsgbuf *ibuf)
438 {
439 	char		 path[PATH_MAX];
440 	int		 i, p[2];
441 	struct vhost	*h;
442 	struct location	*l;
443 
444 	if (config_path == NULL) {
445 		if (hostname == NULL)
446 			hostname = "localhost";
447 		if (certs_dir == NULL)
448 			certs_dir = data_dir();
449 		load_local_cert(hostname, certs_dir);
450 
451 		h = TAILQ_FIRST(&hosts);
452 		h->domain = "*";
453 
454 		l = TAILQ_FIRST(&h->locations);
455 		l->auto_index = 1;
456 		l->match = "*";
457 
458 		switch (argc) {
459 		case 0:
460 			l->dir = getcwd(path, sizeof(path));
461 			break;
462 		case 1:
463 			l->dir = absolutify_path(argv[0]);
464 			break;
465 		default:
466 			usage();
467 			return 1;
468 		}
469 
470 		log_notice(NULL, "serving %s on port %d", l->dir, conf.port);
471 	}
472 
473 	/* setup tls before dropping privileges: we don't want user
474 	 * to put private certs inside the chroot. */
475 	setup_tls();
476 
477 	for (i = 0; i < conf.prefork; ++i) {
478 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
479 		    PF_UNSPEC, p) == -1)
480 			fatal("socketpair: %s", strerror(errno));
481 
482 		switch (fork()) {
483 		case -1:
484 			fatal("fork: %s", strerror(errno));
485 		case 0:		/* child */
486 			close(p[0]);
487 			imsg_init(&exibuf, p[1]);
488 			setproctitle("server");
489 			_exit(listener_main(&exibuf));
490 		default:
491 			close(p[1]);
492 			imsg_init(&servibuf[i], p[0]);
493 		}
494 	}
495 
496 	setproctitle("executor");
497 	drop_priv();
498 	_exit(executor_main(ibuf));
499 }
500 
501 static int
502 write_pidfile(const char *pidfile)
503 {
504 	struct flock	lock;
505 	int		fd;
506 
507 	if (pidfile == NULL)
508 		return -1;
509 
510 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
511 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
512 
513 	lock.l_start = 0;
514 	lock.l_len = 0;
515 	lock.l_type = F_WRLCK;
516 	lock.l_whence = SEEK_SET;
517 
518 	if (fcntl(fd, F_SETLK, &lock) == -1)
519 		fatal("can't lock %s, gmid is already running?", pidfile);
520 
521 	if (ftruncate(fd, 0) == -1)
522 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
523 
524 	dprintf(fd, "%d\n", getpid());
525 
526 	return fd;
527 }
528 
529 static void
530 setup_configless(int argc, char **argv, const char *cgi)
531 {
532 	struct vhost	*host;
533 	struct location	*loc;
534 
535 	host = xcalloc(1, sizeof(*host));
536 	host->cgi = cgi;
537 	TAILQ_INSERT_HEAD(&hosts, host, vhosts);
538 
539 	loc = xcalloc(1, sizeof(*loc));
540 	loc->fcgi = -1;
541 	TAILQ_INSERT_HEAD(&host->locations, loc, locations);
542 
543 	serve(argc, argv, NULL);
544 
545 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
546 	imsg_flush(&logibuf);
547 }
548 
549 static int
550 parse_portno(const char *p)
551 {
552 	const char *errstr;
553 	int n;
554 
555 	n = strtonum(p, 0, UINT16_MAX, &errstr);
556 	if (errstr != NULL)
557 		yyerror("port number is %s: %s", errstr, p);
558 	return n;
559 }
560 
561 int
562 main(int argc, char **argv)
563 {
564 	struct imsgbuf exibuf;
565 	int ch, conftest = 0, configless = 0;
566 	int pidfd, old_ipv6, old_port;
567 
568 	logger_init();
569 	init_config();
570 
571 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
572 		switch (ch) {
573 		case '6':
574 			conf.ipv6 = 1;
575 			configless = 1;
576 			break;
577 
578 		case 'c':
579 			config_path = absolutify_path(optarg);
580 			break;
581 
582 		case 'D':
583 			if (cmdline_symset(optarg) == -1)
584 				fatal("could not parse macro definition: %s",
585 				    optarg);
586 			break;
587 
588 		case 'd':
589 			certs_dir = optarg;
590 			configless = 1;
591 			break;
592 
593 		case 'f':
594 			conf.foreground = 1;
595 			break;
596 
597 		case 'H':
598 			hostname = optarg;
599 			configless = 1;
600 			break;
601 
602 		case 'h':
603 			usage();
604 			return 0;
605 
606 		case 'n':
607 			conftest++;
608 			break;
609 
610 		case 'P':
611 			pidfile = optarg;
612 			break;
613 
614 		case 'p':
615 			conf.port = parse_portno(optarg);
616 			configless = 1;
617 			break;
618 
619 		case 'V':
620 			puts("Version: " GMID_STRING);
621 			return 0;
622 
623 		case 'v':
624 			conf.verbose++;
625 			break;
626 
627 		case 'x':
628 			/* drop the starting / (if any) */
629 			if (*optarg == '/')
630 				optarg++;
631 			cgi = optarg;
632 			configless = 1;
633 			break;
634 
635 		default:
636 			usage();
637 			return 1;
638 		}
639 	}
640 	argc -= optind;
641 	argv += optind;
642 
643 	if (config_path == NULL) {
644 		configless = 1;
645 		conf.foreground = 1;
646 		conf.prefork = 1;
647 		conf.verbose++;
648 	}
649 
650 	if (config_path != NULL && (argc > 0 || configless))
651 		fatal("can't specify options in config mode.");
652 
653 	if (conftest) {
654 		if (config_path == NULL)
655 			fatal("missing configuration");
656 		parse_conf(config_path);
657 		fprintf(stderr, "config OK\n");
658 		if (conftest > 1)
659 			print_conf();
660 		return 0;
661 	}
662 
663 	if (!conf.foreground && !configless) {
664 		/* log to syslog */
665 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
666 		imsg_flush(&logibuf);
667 
668 		if (daemon(1, 1) == -1)
669 			fatal("daemon: %s", strerror(errno));
670 	}
671 
672 	if (config_path != NULL)
673 		parse_conf(config_path);
674 
675 	sock4 = make_socket(conf.port, AF_INET);
676 	sock6 = -1;
677 	if (conf.ipv6)
678 		sock6 = make_socket(conf.port, AF_INET6);
679 
680 	signal(SIGPIPE, SIG_IGN);
681 	signal(SIGCHLD, SIG_IGN);
682 
683 	if (configless) {
684 		setup_configless(argc, argv, cgi);
685 		return 0;
686 	}
687 
688 	pidfd = write_pidfile(pidfile);
689 
690 	/*
691 	 * Linux seems to call the event handlers even when we're
692 	 * doing a sigwait.  These dummy handlers are here to avoid
693 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
694 	 */
695 	signal(SIGHUP, dummy_handler);
696 	signal(SIGINT, dummy_handler);
697 	signal(SIGTERM, dummy_handler);
698 
699 	/* wait a sighup and reload the daemon */
700 	for (;;) {
701 		int p[2];
702 
703 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
704 		    PF_UNSPEC, p) == -1)
705 			fatal("socketpair: %s", strerror(errno));
706 
707 		switch (fork()) {
708 		case -1:
709 			fatal("fork: %s", strerror(errno));
710 		case 0:
711 			close(p[0]);
712 			imsg_init(&exibuf, p[1]);
713 			_exit(serve(argc, argv, &exibuf));
714 		}
715 
716 		close(p[1]);
717 		imsg_init(&exibuf, p[0]);
718 
719 		if (!wait_signal())
720 			break;
721 
722 		log_info(NULL, "reloading configuration %s", config_path);
723 
724 		/* close the executor (it'll close the servers too) */
725 		imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
726 		imsg_flush(&exibuf);
727 		close(p[0]);
728 
729 		old_ipv6 = conf.ipv6;
730 		old_port = conf.port;
731 
732 		free_config();
733 		init_config();
734 		parse_conf(config_path);
735 
736 		if (old_port != conf.port) {
737 			close(sock4);
738 			close(sock6);
739 			sock4 = -1;
740 			sock6 = -1;
741 		}
742 
743 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
744 			close(sock6);
745 			sock6 = -1;
746 		}
747 
748 		if (sock4 == -1)
749 			sock4 = make_socket(conf.port, AF_INET);
750 		if (sock6 == -1 && conf.ipv6)
751 			sock6 = make_socket(conf.port, AF_INET6);
752 	}
753 
754 	imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
755 	imsg_flush(&exibuf);
756 
757 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
758 	imsg_flush(&logibuf);
759 
760 	if (pidfd != -1)
761 		close(pidfd);
762 
763 	return 0;
764 }