1 /*
2  * Copyright (c) 2020, 2021, 2022 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 const 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;
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(struct vhost *h, const char *hostname, const char *dir)
107 {
108 	char *cert, *key;
109 
110 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
111 		errx(1, "asprintf");
112 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
113 		errx(1, "asprintf");
114 
115 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
116 		gen_certificate(hostname, cert, key);
117 
118 	h->cert = cert;
119 	h->key = key;
120 	h->domain = hostname;
121 }
122 
123 void
124 load_vhosts(void)
125 {
126 	struct vhost	*h;
127 	struct location	*l;
128 
129 	TAILQ_FOREACH(h, &hosts, vhosts) {
130 		TAILQ_FOREACH(l, &h->locations, locations) {
131 			if (l->dir == NULL)
132 				continue;
133 			if ((l->dirfd = open(l->dir, O_RDONLY | O_DIRECTORY)) == -1)
134 				fatal("open %s for domain %s: %s", l->dir, h->domain,
135 				    strerror(errno));
136 		}
137 	}
138 }
139 
140 int
141 make_socket(int port, int family)
142 {
143 	int sock, v;
144 	struct sockaddr_in addr4;
145 	struct sockaddr_in6 addr6;
146 	struct sockaddr *addr;
147 	socklen_t len;
148 
149 	switch (family) {
150 	case AF_INET:
151 		memset(&addr4, 0, sizeof(addr4));
152 		addr4.sin_family = family;
153 		addr4.sin_port = htons(port);
154 		addr4.sin_addr.s_addr = INADDR_ANY;
155 		addr = (struct sockaddr*)&addr4;
156 		len = sizeof(addr4);
157 		break;
158 
159 	case AF_INET6:
160 		memset(&addr6, 0, sizeof(addr6));
161 		addr6.sin6_family = AF_INET6;
162 		addr6.sin6_port = htons(port);
163 		addr6.sin6_addr = in6addr_any;
164 		addr = (struct sockaddr*)&addr6;
165 		len = sizeof(addr6);
166 		break;
167 
168 	default:
169 		/* unreachable */
170 		abort();
171 	}
172 
173 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
174 		fatal("socket: %s", strerror(errno));
175 
176 	v = 1;
177 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
178 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
179 
180 	v = 1;
181 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
182 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
183 
184 	mark_nonblock(sock);
185 
186 	if (bind(sock, addr, len) == -1)
187 		fatal("bind: %s", strerror(errno));
188 
189 	if (listen(sock, 16) == -1)
190 		fatal("listen: %s", strerror(errno));
191 
192 	return sock;
193 }
194 
195 static void
196 add_keypair(struct vhost *h)
197 {
198 	if (h->ocsp == NULL) {
199 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
200 			fatal("failed to load the keypair (%s, %s)",
201 			    h->cert, h->key);
202 	} else {
203 		if (tls_config_add_keypair_ocsp_file(tlsconf, h->cert, h->key,
204 		    h->ocsp) == -1)
205 			fatal("failed to load the keypair (%s, %s, %s)",
206 			    h->cert, h->key, h->ocsp);
207 	}
208 }
209 
210 void
211 setup_tls(void)
212 {
213 	struct vhost *h;
214 
215 	if ((tlsconf = tls_config_new()) == NULL)
216 		fatal("tls_config_new");
217 
218 	/* optionally accept client certs, but don't try to verify them */
219 	tls_config_verify_client_optional(tlsconf);
220 	tls_config_insecure_noverifycert(tlsconf);
221 
222 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
223 		fatal("tls_config_set_protocols");
224 
225 	if ((ctx = tls_server()) == NULL)
226 		fatal("tls_server failure");
227 
228 	h = TAILQ_FIRST(&hosts);
229 
230 	/* we need to set something, then we can add how many key we want */
231 	if (tls_config_set_keypair_file(tlsconf, h->cert, h->key))
232 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
233 		    h->cert, h->key);
234 
235 	/* same for OCSP */
236 	if (h->ocsp != NULL &&
237 	    tls_config_set_ocsp_staple_file(tlsconf, h->ocsp) == -1)
238 		fatal("tls_config_set_ocsp_staple_file failed for (%s)",
239 		    h->ocsp);
240 
241 	while ((h = TAILQ_NEXT(h, vhosts)) != NULL)
242 		add_keypair(h);
243 
244 	if (tls_configure(ctx, tlsconf) == -1)
245 		fatal("tls_configure: %s", tls_error(ctx));
246 }
247 
248 static int
249 listener_main(struct imsgbuf *ibuf)
250 {
251 	drop_priv();
252 	if (!conf.mime.skip_defaults && load_default_mime(&conf.mime) == -1)
253 		fatal("load_default_mime: %s", strerror(errno));
254 	sort_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 proxy *p, *tp;
283 	struct envlist *e, *te;
284 	struct alist *a, *ta;
285 	int v, i;
286 
287 	v = conf.verbose;
288 
289 	free_mime(&conf.mime);
290 	free(conf.chroot);
291 	free(conf.user);
292 	memset(&conf, 0, sizeof(conf));
293 
294 	conf.verbose = v;
295 
296 	TAILQ_FOREACH_SAFE(h, &hosts, vhosts, th) {
297 		TAILQ_FOREACH_SAFE(l, &h->locations, locations, tl) {
298 			TAILQ_REMOVE(&h->locations, l, locations);
299 
300 			free((char*)l->match);
301 			free((char*)l->lang);
302 			free((char*)l->default_mime);
303 			free((char*)l->index);
304 			free((char*)l->block_fmt);
305 			free((char*)l->dir);
306 
307 			if (l->dirfd != -1)
308 				close(l->dirfd);
309 
310 			free(l);
311 		}
312 
313 		TAILQ_FOREACH_SAFE(e, &h->env, envs, te) {
314 			TAILQ_REMOVE(&h->env, e, envs);
315 
316 			free(e->name);
317 			free(e->value);
318 			free(e);
319 		}
320 
321 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
322 			TAILQ_REMOVE(&h->params, e, envs);
323 
324 			free(e->name);
325 			free(e->value);
326 			free(e);
327 		}
328 
329 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
330 			TAILQ_REMOVE(&h->aliases, a, aliases);
331 
332 			free(a->alias);
333 			free(a);
334 		}
335 
336 		TAILQ_FOREACH_SAFE(p, &h->proxies, proxies, tp) {
337 			TAILQ_REMOVE(&h->proxies, p, proxies);
338 
339 			free(p->match_proto);
340 			free(p->match_host);
341 			free(p->host);
342 			free(p->sni);
343 			tls_unload_file(p->cert, p->certlen);
344 			tls_unload_file(p->key, p->keylen);
345 			free(p);
346 		}
347 
348 		free((char*)h->domain);
349 		free((char*)h->cert);
350 		free((char*)h->key);
351 		free((char*)h->ocsp);
352 		free((char*)h->entrypoint);
353 
354 		TAILQ_REMOVE(&hosts, h, vhosts);
355 		free(h);
356 	}
357 
358 	for (i = 0; i < FCGI_MAX; ++i) {
359 		if (fcgi[i].path == NULL && fcgi[i].prog == NULL)
360 			break;
361 		free(fcgi[i].path);
362 		free(fcgi[i].port);
363 		free(fcgi[i].prog);
364 
365 		fcgi[i].path = NULL;
366 		fcgi[i].port = NULL;
367 		fcgi[i].prog = NULL;
368 	}
369 
370 	tls_free(ctx);
371 	tls_config_free(tlsconf);
372 }
373 
374 static int
375 wait_signal(void)
376 {
377 	sigset_t mask;
378 	int signo;
379 
380 	sigemptyset(&mask);
381 	sigaddset(&mask, SIGHUP);
382 	sigaddset(&mask, SIGINT);
383 	sigaddset(&mask, SIGTERM);
384 	sigwait(&mask, &signo);
385 
386 	return signo == SIGHUP;
387 }
388 
389 void
390 drop_priv(void)
391 {
392 	struct passwd *pw = NULL;
393 
394 	if (conf.chroot != NULL && conf.user == NULL)
395 		fatal("can't chroot without an user to switch to after.");
396 
397 	if (conf.user != NULL) {
398 		if ((pw = getpwnam(conf.user)) == NULL)
399 			fatal("can't find user %s", conf.user);
400 	}
401 
402 	if (conf.chroot != NULL) {
403 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
404 			fatal("%s: %s", conf.chroot, strerror(errno));
405 	}
406 
407 	if (pw != NULL) {
408 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
409 			fatal("setresuid(%d): %s", pw->pw_uid,
410 			    strerror(errno));
411 	}
412 
413 	if (getuid() == 0)
414 		log_warn(NULL, "not a good idea to run a network daemon as root");
415 }
416 
417 static void
418 usage(void)
419 {
420 	fprintf(stderr,
421 	    "Version: " GMID_STRING "\n"
422 	    "Usage: %s [-fnv] [-c config] [-D macro=value] [-P pidfile]\n"
423 	    "       %s [-6hVv] [-d certs-dir] [-H hostname] [-p port] [dir]\n",
424 	    getprogname(),
425 	    getprogname());
426 }
427 
428 static void
429 logger_init(void)
430 {
431 	int p[2];
432 
433 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
434 		err(1, "socketpair");
435 
436 	switch (fork()) {
437 	case -1:
438 		err(1, "fork");
439 	case 0:
440 		signal(SIGHUP, SIG_IGN);
441 		close(p[0]);
442 		setproctitle("logger");
443 		imsg_init(&logibuf, p[1]);
444 		drop_priv();
445 		_exit(logger_main(p[1], &logibuf));
446 	default:
447 		close(p[1]);
448 		imsg_init(&logibuf, p[0]);
449 		return;
450 	}
451 }
452 
453 static void
454 serve(void)
455 {
456 	int i, p[2];
457 
458 	/* setup tls before dropping privileges: we don't want user
459 	 * to put private certs inside the chroot. */
460 	setup_tls();
461 
462 	for (i = 0; i < conf.prefork; ++i) {
463 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
464 		    PF_UNSPEC, p) == -1)
465 			fatal("socketpair: %s", strerror(errno));
466 
467 		switch (fork()) {
468 		case -1:
469 			fatal("fork: %s", strerror(errno));
470 		case 0:		/* child */
471 			close(p[0]);
472 			imsg_init(&exibuf, p[1]);
473 			setproctitle("server");
474 			_exit(listener_main(&exibuf));
475 		default:
476 			close(p[1]);
477 			imsg_init(&servibuf[i], p[0]);
478 		}
479 	}
480 }
481 
482 static int
483 write_pidfile(const char *pidfile)
484 {
485 	struct flock	lock;
486 	int		fd;
487 
488 	if (pidfile == NULL)
489 		return -1;
490 
491 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
492 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
493 
494 	lock.l_start = 0;
495 	lock.l_len = 0;
496 	lock.l_type = F_WRLCK;
497 	lock.l_whence = SEEK_SET;
498 
499 	if (fcntl(fd, F_SETLK, &lock) == -1)
500 		fatal("can't lock %s, gmid is already running?", pidfile);
501 
502 	if (ftruncate(fd, 0) == -1)
503 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
504 
505 	dprintf(fd, "%d\n", getpid());
506 
507 	return fd;
508 }
509 
510 static void
511 setup_configless(const char *path)
512 {
513 	char p[PATH_MAX];
514 	struct vhost	*host;
515 	struct location	*loc;
516 
517 	if (hostname == NULL)
518 		hostname = "localhost";
519 	if (certs_dir == NULL)
520 		certs_dir = data_dir();
521 
522 	host = xcalloc(1, sizeof(*host));
523 	TAILQ_INSERT_HEAD(&hosts, host, vhosts);
524 
525 	loc = xcalloc(1, sizeof(*loc));
526 	loc->fcgi = -1;
527 	TAILQ_INSERT_HEAD(&host->locations, loc, locations);
528 
529 	load_local_cert(host, hostname, certs_dir);
530 
531 	host->domain = "*";
532 	loc->auto_index = 1;
533 	loc->match = "*";
534 	if (path == NULL)
535 		loc->dir = getcwd(p, sizeof(p));
536 	else
537 		loc->dir = absolutify_path(path);
538 
539 	log_notice(NULL, "serving %s on port %d", loc->dir, conf.port);
540 }
541 
542 static int
543 parse_portno(const char *p)
544 {
545 	const char *errstr;
546 	int n;
547 
548 	n = strtonum(p, 0, UINT16_MAX, &errstr);
549 	if (errstr != NULL)
550 		yyerror("port number is %s: %s", errstr, p);
551 	return n;
552 }
553 
554 int
555 main(int argc, char **argv)
556 {
557 	int i, ch, conftest = 0, configless = 0;
558 	int pidfd, old_ipv6, old_port;
559 
560 	logger_init();
561 	init_config();
562 
563 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
564 		switch (ch) {
565 		case '6':
566 			conf.ipv6 = 1;
567 			configless = 1;
568 			break;
569 
570 		case 'c':
571 			config_path = absolutify_path(optarg);
572 			break;
573 
574 		case 'D':
575 			if (cmdline_symset(optarg) == -1)
576 				fatal("could not parse macro definition: %s",
577 				    optarg);
578 			break;
579 
580 		case 'd':
581 			certs_dir = optarg;
582 			configless = 1;
583 			break;
584 
585 		case 'f':
586 			conf.foreground = 1;
587 			break;
588 
589 		case 'H':
590 			hostname = optarg;
591 			configless = 1;
592 			break;
593 
594 		case 'h':
595 			usage();
596 			return 0;
597 
598 		case 'n':
599 			conftest++;
600 			break;
601 
602 		case 'P':
603 			pidfile = optarg;
604 			break;
605 
606 		case 'p':
607 			conf.port = parse_portno(optarg);
608 			configless = 1;
609 			break;
610 
611 		case 'V':
612 			puts("Version: " GMID_STRING);
613 			return 0;
614 
615 		case 'v':
616 			conf.verbose++;
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 (argc > 1 || (configless && argc != 0))
635 		usage();
636 
637 	if (config_path != NULL && (argc > 0 || configless))
638 		fatal("can't specify options in config mode.");
639 
640 	if (conftest) {
641 		if (config_path == NULL)
642 			fatal("missing configuration");
643 		parse_conf(config_path);
644 		fprintf(stderr, "config OK\n");
645 		if (conftest > 1)
646 			print_conf();
647 		return 0;
648 	}
649 
650 	if (!conf.foreground && !configless) {
651 		/* log to syslog */
652 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
653 		imsg_flush(&logibuf);
654 
655 		if (daemon(1, 1) == -1)
656 			fatal("daemon: %s", strerror(errno));
657 	}
658 
659 	if (config_path != NULL)
660 		parse_conf(config_path);
661 	else
662 		setup_configless(*argv);
663 
664 	sock4 = make_socket(conf.port, AF_INET);
665 	sock6 = -1;
666 	if (conf.ipv6)
667 		sock6 = make_socket(conf.port, AF_INET6);
668 
669 	signal(SIGPIPE, SIG_IGN);
670 
671 	pidfd = write_pidfile(pidfile);
672 
673 	/*
674 	 * Linux seems to call the event handlers even when we're
675 	 * doing a sigwait.  These dummy handlers are here to avoid
676 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
677 	 */
678 	signal(SIGHUP, dummy_handler);
679 	signal(SIGINT, dummy_handler);
680 	signal(SIGTERM, dummy_handler);
681 
682 	/* wait a sighup and reload the daemon */
683 	for (;;) {
684 		serve();
685 
686 		if (!wait_signal() || configless)
687 			break;
688 
689 		log_info(NULL, "reloading configuration %s", config_path);
690 
691 		/* close the servers */
692 		for (i = 0; i < conf.prefork; ++i) {
693 			imsg_compose(&servibuf[i], IMSG_QUIT, 0, 0, -1, NULL, 0);
694 			imsg_flush(&servibuf[i]);
695 			close(servibuf[i].fd);
696 		}
697 
698 		old_ipv6 = conf.ipv6;
699 		old_port = conf.port;
700 
701 		free_config();
702 		init_config();
703 		parse_conf(config_path);
704 
705 		if (old_port != conf.port) {
706 			close(sock4);
707 			close(sock6);
708 			sock4 = -1;
709 			sock6 = -1;
710 		}
711 
712 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
713 			close(sock6);
714 			sock6 = -1;
715 		}
716 
717 		if (sock4 == -1)
718 			sock4 = make_socket(conf.port, AF_INET);
719 		if (sock6 == -1 && conf.ipv6)
720 			sock6 = make_socket(conf.port, AF_INET6);
721 	}
722 
723 	imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
724 	imsg_flush(&exibuf);
725 
726 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
727 	imsg_flush(&logibuf);
728 
729 	if (pidfd != -1)
730 		close(pidfd);
731 
732 	return 0;
733 }