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,
206 		    h->ocsp) == -1)
207 			fatal("failed to load the keypair (%s, %s, %s)",
208 			    h->cert, h->key, h->ocsp);
209 	}
210 }
211 
212 void
213 setup_tls(void)
214 {
215 	struct vhost *h;
216 
217 	if ((tlsconf = tls_config_new()) == NULL)
218 		fatal("tls_config_new");
219 
220 	/* optionally accept client certs, but don't try to verify them */
221 	tls_config_verify_client_optional(tlsconf);
222 	tls_config_insecure_noverifycert(tlsconf);
223 
224 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
225 		fatal("tls_config_set_protocols");
226 
227 	if ((ctx = tls_server()) == NULL)
228 		fatal("tls_server failure");
229 
230 	h = TAILQ_FIRST(&hosts);
231 
232 	/* we need to set something, then we can add how many key we want */
233 	if (tls_config_set_keypair_file(tlsconf, h->cert, h->key))
234 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
235 		    h->cert, h->key);
236 
237 	/* same for OCSP */
238 	if (h->ocsp != NULL &&
239 	    tls_config_set_ocsp_staple_file(tlsconf, h->ocsp) == -1)
240 		fatal("tls_config_set_ocsp_staple_file failed for (%s)",
241 		    h->ocsp);
242 
243 	while ((h = TAILQ_NEXT(h, vhosts)) != NULL)
244 		add_keypair(h);
245 
246 	if (tls_configure(ctx, tlsconf) == -1)
247 		fatal("tls_configure: %s", tls_error(ctx));
248 }
249 
250 static int
251 listener_main(struct imsgbuf *ibuf)
252 {
253 	drop_priv();
254 	load_default_mime(&conf.mime);
255 	load_vhosts();
256 	loop(ctx, sock4, sock6, ibuf);
257 	return 0;
258 }
259 
260 void
261 init_config(void)
262 {
263 	TAILQ_INIT(&hosts);
264 
265 	conf.port = 1965;
266 	conf.ipv6 = 0;
267 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
268 
269 	init_mime(&conf.mime);
270 
271 	conf.chroot = NULL;
272 	conf.user = NULL;
273 
274 	conf.prefork = 3;
275 }
276 
277 void
278 free_config(void)
279 {
280 	struct vhost *h, *th;
281 	struct location *l, *tl;
282 	struct envlist *e, *te;
283 	struct alist *a, *ta;
284 	int v, i;
285 
286 	v = conf.verbose;
287 
288 	free(conf.chroot);
289 	free(conf.user);
290 	memset(&conf, 0, sizeof(conf));
291 
292 	conf.verbose = v;
293 
294 	TAILQ_FOREACH_SAFE(h, &hosts, vhosts, th) {
295 		TAILQ_FOREACH_SAFE(l, &h->locations, locations, tl) {
296 			TAILQ_REMOVE(&h->locations, l, locations);
297 
298 			free((char*)l->match);
299 			free((char*)l->lang);
300 			free((char*)l->default_mime);
301 			free((char*)l->index);
302 			free((char*)l->block_fmt);
303 			free((char*)l->dir);
304 
305 			if (l->dirfd != -1)
306 				close(l->dirfd);
307 
308 			free(l);
309 		}
310 
311 		TAILQ_FOREACH_SAFE(e, &h->env, envs, te) {
312 			TAILQ_REMOVE(&h->env, e, envs);
313 
314 			free(e->name);
315 			free(e->value);
316 			free(e);
317 		}
318 
319 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
320 			TAILQ_REMOVE(&h->params, e, envs);
321 
322 			free(e->name);
323 			free(e->value);
324 			free(e);
325 		}
326 
327 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
328 			TAILQ_REMOVE(&h->aliases, a, aliases);
329 
330 			free(a->alias);
331 			free(a);
332 		}
333 
334 		free((char*)h->domain);
335 		free((char*)h->cert);
336 		free((char*)h->key);
337 		free((char*)h->cgi);
338 		free((char*)h->entrypoint);
339 
340 		TAILQ_REMOVE(&hosts, h, vhosts);
341 		free(h);
342 	}
343 
344 	for (i = 0; i < FCGI_MAX; ++i) {
345 		if (fcgi[i].path == NULL && fcgi[i].prog == NULL)
346 			break;
347 		free(fcgi[i].path);
348 		free(fcgi[i].port);
349 		free(fcgi[i].prog);
350 
351 		fcgi[i].path = NULL;
352 		fcgi[i].port = NULL;
353 		fcgi[i].prog = NULL;
354 	}
355 
356 	tls_free(ctx);
357 	tls_config_free(tlsconf);
358 }
359 
360 static int
361 wait_signal(void)
362 {
363 	sigset_t mask;
364 	int signo;
365 
366 	sigemptyset(&mask);
367 	sigaddset(&mask, SIGHUP);
368 	sigaddset(&mask, SIGINT);
369 	sigaddset(&mask, SIGTERM);
370 	sigwait(&mask, &signo);
371 
372 	return signo == SIGHUP;
373 }
374 
375 void
376 drop_priv(void)
377 {
378 	struct passwd *pw = NULL;
379 
380 	if (conf.chroot != NULL && conf.user == NULL)
381 		fatal("can't chroot without an user to switch to after.");
382 
383 	if (conf.user != NULL) {
384 		if ((pw = getpwnam(conf.user)) == NULL)
385 			fatal("can't find user %s", conf.user);
386 	}
387 
388 	if (conf.chroot != NULL) {
389 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
390 			fatal("%s: %s", conf.chroot, strerror(errno));
391 	}
392 
393 	if (pw != NULL) {
394 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
395 			fatal("setresuid(%d): %s", pw->pw_uid,
396 			    strerror(errno));
397 	}
398 
399 	if (getuid() == 0)
400 		log_warn(NULL, "not a good idea to run a network daemon as root");
401 }
402 
403 static void
404 usage(void)
405 {
406 	fprintf(stderr,
407 	    "Version: " GMID_STRING "\n"
408 	    "Usage: %s [-fnv] [-c config] [-D macro=value] [-P pidfile]\n"
409 	    "       %s [-6hVv] [-d certs-dir] [-H hostname] [-p port] [-x cgi] [dir]\n",
410 	    getprogname(),
411 	    getprogname());
412 }
413 
414 static void
415 logger_init(void)
416 {
417 	int p[2];
418 
419 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
420 		err(1, "socketpair");
421 
422 	switch (fork()) {
423 	case -1:
424 		err(1, "fork");
425 	case 0:
426 		signal(SIGHUP, SIG_IGN);
427 		close(p[0]);
428 		setproctitle("logger");
429 		imsg_init(&logibuf, p[1]);
430 		drop_priv();
431 		_exit(logger_main(p[1], &logibuf));
432 	default:
433 		close(p[1]);
434 		imsg_init(&logibuf, p[0]);
435 		return;
436 	}
437 }
438 
439 static int
440 serve(int argc, char **argv, struct imsgbuf *ibuf)
441 {
442 	char		 path[PATH_MAX];
443 	int		 i, p[2];
444 	struct vhost	*h;
445 	struct location	*l;
446 
447 	if (config_path == NULL) {
448 		if (hostname == NULL)
449 			hostname = "localhost";
450 		if (certs_dir == NULL)
451 			certs_dir = data_dir();
452 		load_local_cert(hostname, certs_dir);
453 
454 		h = TAILQ_FIRST(&hosts);
455 		h->domain = "*";
456 
457 		l = TAILQ_FIRST(&h->locations);
458 		l->auto_index = 1;
459 		l->match = "*";
460 
461 		switch (argc) {
462 		case 0:
463 			l->dir = getcwd(path, sizeof(path));
464 			break;
465 		case 1:
466 			l->dir = absolutify_path(argv[0]);
467 			break;
468 		default:
469 			usage();
470 			return 1;
471 		}
472 
473 		log_notice(NULL, "serving %s on port %d", l->dir, conf.port);
474 	}
475 
476 	/* setup tls before dropping privileges: we don't want user
477 	 * to put private certs inside the chroot. */
478 	setup_tls();
479 
480 	for (i = 0; i < conf.prefork; ++i) {
481 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
482 		    PF_UNSPEC, p) == -1)
483 			fatal("socketpair: %s", strerror(errno));
484 
485 		switch (fork()) {
486 		case -1:
487 			fatal("fork: %s", strerror(errno));
488 		case 0:		/* child */
489 			close(p[0]);
490 			imsg_init(&exibuf, p[1]);
491 			setproctitle("server");
492 			_exit(listener_main(&exibuf));
493 		default:
494 			close(p[1]);
495 			imsg_init(&servibuf[i], p[0]);
496 		}
497 	}
498 
499 	setproctitle("executor");
500 	drop_priv();
501 	_exit(executor_main(ibuf));
502 }
503 
504 static int
505 write_pidfile(const char *pidfile)
506 {
507 	struct flock	lock;
508 	int		fd;
509 
510 	if (pidfile == NULL)
511 		return -1;
512 
513 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
514 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
515 
516 	lock.l_start = 0;
517 	lock.l_len = 0;
518 	lock.l_type = F_WRLCK;
519 	lock.l_whence = SEEK_SET;
520 
521 	if (fcntl(fd, F_SETLK, &lock) == -1)
522 		fatal("can't lock %s, gmid is already running?", pidfile);
523 
524 	if (ftruncate(fd, 0) == -1)
525 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
526 
527 	dprintf(fd, "%d\n", getpid());
528 
529 	return fd;
530 }
531 
532 static void
533 setup_configless(int argc, char **argv, const char *cgi)
534 {
535 	struct vhost	*host;
536 	struct location	*loc;
537 
538 	host = xcalloc(1, sizeof(*host));
539 	host->cgi = cgi;
540 	TAILQ_INSERT_HEAD(&hosts, host, vhosts);
541 
542 	loc = xcalloc(1, sizeof(*loc));
543 	loc->fcgi = -1;
544 	TAILQ_INSERT_HEAD(&host->locations, loc, locations);
545 
546 	serve(argc, argv, NULL);
547 
548 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
549 	imsg_flush(&logibuf);
550 }
551 
552 static int
553 parse_portno(const char *p)
554 {
555 	const char *errstr;
556 	int n;
557 
558 	n = strtonum(p, 0, UINT16_MAX, &errstr);
559 	if (errstr != NULL)
560 		yyerror("port number is %s: %s", errstr, p);
561 	return n;
562 }
563 
564 int
565 main(int argc, char **argv)
566 {
567 	struct imsgbuf exibuf;
568 	int ch, conftest = 0, configless = 0;
569 	int pidfd, old_ipv6, old_port;
570 
571 	logger_init();
572 	init_config();
573 
574 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
575 		switch (ch) {
576 		case '6':
577 			conf.ipv6 = 1;
578 			configless = 1;
579 			break;
580 
581 		case 'c':
582 			config_path = absolutify_path(optarg);
583 			break;
584 
585 		case 'D':
586 			if (cmdline_symset(optarg) == -1)
587 				fatal("could not parse macro definition: %s",
588 				    optarg);
589 			break;
590 
591 		case 'd':
592 			certs_dir = optarg;
593 			configless = 1;
594 			break;
595 
596 		case 'f':
597 			conf.foreground = 1;
598 			break;
599 
600 		case 'H':
601 			hostname = optarg;
602 			configless = 1;
603 			break;
604 
605 		case 'h':
606 			usage();
607 			return 0;
608 
609 		case 'n':
610 			conftest++;
611 			break;
612 
613 		case 'P':
614 			pidfile = optarg;
615 			break;
616 
617 		case 'p':
618 			conf.port = parse_portno(optarg);
619 			configless = 1;
620 			break;
621 
622 		case 'V':
623 			puts("Version: " GMID_STRING);
624 			return 0;
625 
626 		case 'v':
627 			conf.verbose++;
628 			break;
629 
630 		case 'x':
631 			/* drop the starting / (if any) */
632 			if (*optarg == '/')
633 				optarg++;
634 			cgi = optarg;
635 			configless = 1;
636 			break;
637 
638 		default:
639 			usage();
640 			return 1;
641 		}
642 	}
643 	argc -= optind;
644 	argv += optind;
645 
646 	if (config_path == NULL) {
647 		configless = 1;
648 		conf.foreground = 1;
649 		conf.prefork = 1;
650 		conf.verbose++;
651 	}
652 
653 	if (config_path != NULL && (argc > 0 || configless))
654 		fatal("can't specify options in config mode.");
655 
656 	if (conftest) {
657 		if (config_path == NULL)
658 			fatal("missing configuration");
659 		parse_conf(config_path);
660 		fprintf(stderr, "config OK\n");
661 		if (conftest > 1)
662 			print_conf();
663 		return 0;
664 	}
665 
666 	if (!conf.foreground && !configless) {
667 		/* log to syslog */
668 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
669 		imsg_flush(&logibuf);
670 
671 		if (daemon(1, 1) == -1)
672 			fatal("daemon: %s", strerror(errno));
673 	}
674 
675 	if (config_path != NULL)
676 		parse_conf(config_path);
677 
678 	sock4 = make_socket(conf.port, AF_INET);
679 	sock6 = -1;
680 	if (conf.ipv6)
681 		sock6 = make_socket(conf.port, AF_INET6);
682 
683 	signal(SIGPIPE, SIG_IGN);
684 	signal(SIGCHLD, SIG_IGN);
685 
686 	if (configless) {
687 		setup_configless(argc, argv, cgi);
688 		return 0;
689 	}
690 
691 	pidfd = write_pidfile(pidfile);
692 
693 	/*
694 	 * Linux seems to call the event handlers even when we're
695 	 * doing a sigwait.  These dummy handlers are here to avoid
696 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
697 	 */
698 	signal(SIGHUP, dummy_handler);
699 	signal(SIGINT, dummy_handler);
700 	signal(SIGTERM, dummy_handler);
701 
702 	/* wait a sighup and reload the daemon */
703 	for (;;) {
704 		int p[2];
705 
706 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
707 		    PF_UNSPEC, p) == -1)
708 			fatal("socketpair: %s", strerror(errno));
709 
710 		switch (fork()) {
711 		case -1:
712 			fatal("fork: %s", strerror(errno));
713 		case 0:
714 			close(p[0]);
715 			imsg_init(&exibuf, p[1]);
716 			_exit(serve(argc, argv, &exibuf));
717 		}
718 
719 		close(p[1]);
720 		imsg_init(&exibuf, p[0]);
721 
722 		if (!wait_signal())
723 			break;
724 
725 		log_info(NULL, "reloading configuration %s", config_path);
726 
727 		/* close the executor (it'll close the servers too) */
728 		imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
729 		imsg_flush(&exibuf);
730 		close(p[0]);
731 
732 		old_ipv6 = conf.ipv6;
733 		old_port = conf.port;
734 
735 		free_config();
736 		init_config();
737 		parse_conf(config_path);
738 
739 		if (old_port != conf.port) {
740 			close(sock4);
741 			close(sock6);
742 			sock4 = -1;
743 			sock6 = -1;
744 		}
745 
746 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
747 			close(sock6);
748 			sock6 = -1;
749 		}
750 
751 		if (sock4 == -1)
752 			sock4 = make_socket(conf.port, AF_INET);
753 		if (sock6 == -1 && conf.ipv6)
754 			sock6 = make_socket(conf.port, AF_INET6);
755 	}
756 
757 	imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
758 	imsg_flush(&exibuf);
759 
760 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
761 	imsg_flush(&logibuf);
762 
763 	if (pidfd != -1)
764 		close(pidfd);
765 
766 	return 0;
767 }