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 = "D:df:hnP:Vv";
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 = "/etc/gmid.conf";
47 const char *pidfile;
48 
49 struct conf conf;
50 
51 struct tls_config *tlsconf;
52 struct tls *ctx;
53 
54 static void
55 dummy_handler(int signo)
56 {
57 	return;
58 }
59 
60 void
61 load_vhosts(void)
62 {
63 	struct vhost	*h;
64 	struct location	*l;
65 
66 	TAILQ_FOREACH(h, &hosts, vhosts) {
67 		TAILQ_FOREACH(l, &h->locations, locations) {
68 			if (l->dir == NULL)
69 				continue;
70 			if ((l->dirfd = open(l->dir, O_RDONLY | O_DIRECTORY)) == -1)
71 				fatal("open %s for domain %s: %s", l->dir, h->domain,
72 				    strerror(errno));
73 		}
74 	}
75 }
76 
77 int
78 make_socket(int port, int family)
79 {
80 	int sock, v;
81 	struct sockaddr_in addr4;
82 	struct sockaddr_in6 addr6;
83 	struct sockaddr *addr;
84 	socklen_t len;
85 
86 	switch (family) {
87 	case AF_INET:
88 		memset(&addr4, 0, sizeof(addr4));
89 		addr4.sin_family = family;
90 		addr4.sin_port = htons(port);
91 		addr4.sin_addr.s_addr = INADDR_ANY;
92 		addr = (struct sockaddr*)&addr4;
93 		len = sizeof(addr4);
94 		break;
95 
96 	case AF_INET6:
97 		memset(&addr6, 0, sizeof(addr6));
98 		addr6.sin6_family = AF_INET6;
99 		addr6.sin6_port = htons(port);
100 		addr6.sin6_addr = in6addr_any;
101 		addr = (struct sockaddr*)&addr6;
102 		len = sizeof(addr6);
103 		break;
104 
105 	default:
106 		/* unreachable */
107 		abort();
108 	}
109 
110 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
111 		fatal("socket: %s", strerror(errno));
112 
113 	v = 1;
114 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
115 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
116 
117 	v = 1;
118 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
119 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
120 
121 	mark_nonblock(sock);
122 
123 	if (bind(sock, addr, len) == -1)
124 		fatal("bind: %s", strerror(errno));
125 
126 	if (listen(sock, 16) == -1)
127 		fatal("listen: %s", strerror(errno));
128 
129 	return sock;
130 }
131 
132 static void
133 add_keypair(struct vhost *h)
134 {
135 	if (h->ocsp == NULL) {
136 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
137 			fatal("failed to load the keypair (%s, %s)",
138 			    h->cert, h->key);
139 	} else {
140 		if (tls_config_add_keypair_ocsp_file(tlsconf, h->cert, h->key,
141 		    h->ocsp) == -1)
142 			fatal("failed to load the keypair (%s, %s, %s)",
143 			    h->cert, h->key, h->ocsp);
144 	}
145 }
146 
147 void
148 setup_tls(void)
149 {
150 	struct vhost *h;
151 
152 	if ((tlsconf = tls_config_new()) == NULL)
153 		fatal("tls_config_new");
154 
155 	/* optionally accept client certs, but don't try to verify them */
156 	tls_config_verify_client_optional(tlsconf);
157 	tls_config_insecure_noverifycert(tlsconf);
158 
159 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
160 		fatal("tls_config_set_protocols");
161 
162 	if ((ctx = tls_server()) == NULL)
163 		fatal("tls_server failure");
164 
165 	h = TAILQ_FIRST(&hosts);
166 
167 	/* we need to set something, then we can add how many key we want */
168 	if (tls_config_set_keypair_file(tlsconf, h->cert, h->key))
169 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
170 		    h->cert, h->key);
171 
172 	/* same for OCSP */
173 	if (h->ocsp != NULL &&
174 	    tls_config_set_ocsp_staple_file(tlsconf, h->ocsp) == -1)
175 		fatal("tls_config_set_ocsp_staple_file failed for (%s)",
176 		    h->ocsp);
177 
178 	while ((h = TAILQ_NEXT(h, vhosts)) != NULL)
179 		add_keypair(h);
180 
181 	if (tls_configure(ctx, tlsconf) == -1)
182 		fatal("tls_configure: %s", tls_error(ctx));
183 }
184 
185 static int
186 listener_main(struct imsgbuf *ibuf)
187 {
188 	drop_priv();
189 	if (load_default_mime(&conf.mime) == -1)
190 		fatal("load_default_mime: %s", strerror(errno));
191 	sort_mime(&conf.mime);
192 	load_vhosts();
193 	loop(ctx, sock4, sock6, ibuf);
194 	return 0;
195 }
196 
197 void
198 init_config(void)
199 {
200 	TAILQ_INIT(&hosts);
201 
202 	conf.port = 1965;
203 	conf.ipv6 = 0;
204 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
205 
206 	init_mime(&conf.mime);
207 
208 	conf.prefork = 3;
209 }
210 
211 void
212 free_config(void)
213 {
214 	struct vhost *h, *th;
215 	struct location *l, *tl;
216 	struct proxy *p, *tp;
217 	struct envlist *e, *te;
218 	struct alist *a, *ta;
219 	int v, i;
220 
221 	v = conf.verbose;
222 
223 	free_mime(&conf.mime);
224 	memset(&conf, 0, sizeof(conf));
225 
226 	conf.verbose = v;
227 
228 	TAILQ_FOREACH_SAFE(h, &hosts, vhosts, th) {
229 		TAILQ_FOREACH_SAFE(l, &h->locations, locations, tl) {
230 			TAILQ_REMOVE(&h->locations, l, locations);
231 
232 			free((char*)l->match);
233 			free((char*)l->lang);
234 			free((char*)l->default_mime);
235 			free((char*)l->index);
236 			free((char*)l->block_fmt);
237 			free((char*)l->dir);
238 
239 			if (l->dirfd != -1)
240 				close(l->dirfd);
241 
242 			free(l);
243 		}
244 
245 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
246 			TAILQ_REMOVE(&h->params, e, envs);
247 
248 			free(e->name);
249 			free(e->value);
250 			free(e);
251 		}
252 
253 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
254 			TAILQ_REMOVE(&h->aliases, a, aliases);
255 
256 			free(a->alias);
257 			free(a);
258 		}
259 
260 		TAILQ_FOREACH_SAFE(p, &h->proxies, proxies, tp) {
261 			TAILQ_REMOVE(&h->proxies, p, proxies);
262 
263 			free(p->match_proto);
264 			free(p->match_host);
265 			free(p->host);
266 			free(p->sni);
267 			tls_unload_file(p->cert, p->certlen);
268 			tls_unload_file(p->key, p->keylen);
269 			free(p);
270 		}
271 
272 		free((char*)h->domain);
273 		free((char*)h->cert);
274 		free((char*)h->key);
275 		free((char*)h->ocsp);
276 		free((char*)h->entrypoint);
277 
278 		TAILQ_REMOVE(&hosts, h, vhosts);
279 		free(h);
280 	}
281 
282 	for (i = 0; i < FCGI_MAX; ++i) {
283 		if (fcgi[i].path == NULL && fcgi[i].prog == NULL)
284 			break;
285 		free(fcgi[i].path);
286 		free(fcgi[i].port);
287 		free(fcgi[i].prog);
288 
289 		fcgi[i].path = NULL;
290 		fcgi[i].port = NULL;
291 		fcgi[i].prog = NULL;
292 	}
293 
294 	tls_free(ctx);
295 	tls_config_free(tlsconf);
296 }
297 
298 static int
299 wait_signal(void)
300 {
301 	sigset_t mask;
302 	int signo;
303 
304 	sigemptyset(&mask);
305 	sigaddset(&mask, SIGHUP);
306 	sigaddset(&mask, SIGINT);
307 	sigaddset(&mask, SIGTERM);
308 	sigwait(&mask, &signo);
309 
310 	return signo == SIGHUP;
311 }
312 
313 void
314 drop_priv(void)
315 {
316 	struct passwd *pw = NULL;
317 
318 	if (*conf.chroot != '\0' && *conf.user == '\0')
319 		fatal("can't chroot without an user to switch to after.");
320 
321 	if (*conf.user != '\0') {
322 		if ((pw = getpwnam(conf.user)) == NULL)
323 			fatal("can't find user %s", conf.user);
324 	}
325 
326 	if (*conf.chroot != '\0') {
327 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
328 			fatal("%s: %s", conf.chroot, strerror(errno));
329 	}
330 
331 	if (pw != NULL) {
332 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
333 			fatal("setresuid(%d): %s", pw->pw_uid,
334 			    strerror(errno));
335 	}
336 
337 	if (getuid() == 0)
338 		log_warn(NULL, "not a good idea to run a network daemon as root");
339 }
340 
341 static void
342 usage(void)
343 {
344 	fprintf(stderr,
345 	    "Version: " GMID_STRING "\n"
346 	    "Usage: %s [-dhnVv] [-D macro=value] [-f config] [-P pidfile]\n",
347 	    getprogname());
348 }
349 
350 static void
351 logger_init(void)
352 {
353 	int p[2];
354 
355 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
356 		err(1, "socketpair");
357 
358 	switch (fork()) {
359 	case -1:
360 		err(1, "fork");
361 	case 0:
362 		signal(SIGHUP, SIG_IGN);
363 		close(p[0]);
364 		setproctitle("logger");
365 		imsg_init(&logibuf, p[1]);
366 		drop_priv();
367 		_exit(logger_main(p[1], &logibuf));
368 	default:
369 		close(p[1]);
370 		imsg_init(&logibuf, p[0]);
371 		return;
372 	}
373 }
374 
375 static void
376 serve(void)
377 {
378 	int i, p[2];
379 
380 	/* setup tls before dropping privileges: we don't want user
381 	 * to put private certs inside the chroot. */
382 	setup_tls();
383 
384 	for (i = 0; i < conf.prefork; ++i) {
385 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
386 		    PF_UNSPEC, p) == -1)
387 			fatal("socketpair: %s", strerror(errno));
388 
389 		switch (fork()) {
390 		case -1:
391 			fatal("fork: %s", strerror(errno));
392 		case 0:		/* child */
393 			close(p[0]);
394 			imsg_init(&exibuf, p[1]);
395 			setproctitle("server");
396 			_exit(listener_main(&exibuf));
397 		default:
398 			close(p[1]);
399 			imsg_init(&servibuf[i], p[0]);
400 		}
401 	}
402 }
403 
404 static int
405 write_pidfile(const char *pidfile)
406 {
407 	struct flock	lock;
408 	int		fd;
409 
410 	if (pidfile == NULL)
411 		return -1;
412 
413 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
414 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
415 
416 	lock.l_start = 0;
417 	lock.l_len = 0;
418 	lock.l_type = F_WRLCK;
419 	lock.l_whence = SEEK_SET;
420 
421 	if (fcntl(fd, F_SETLK, &lock) == -1)
422 		fatal("can't lock %s, gmid is already running?", pidfile);
423 
424 	if (ftruncate(fd, 0) == -1)
425 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
426 
427 	dprintf(fd, "%d\n", getpid());
428 
429 	return fd;
430 }
431 
432 int
433 main(int argc, char **argv)
434 {
435 	int i, ch, conftest = 0;
436 	int pidfd, old_ipv6, old_port;
437 
438 	logger_init();
439 	init_config();
440 
441 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
442 		switch (ch) {
443 		case 'D':
444 			if (cmdline_symset(optarg) == -1)
445 				fatal("could not parse macro definition: %s",
446 				    optarg);
447 			break;
448 
449 		case 'd':
450 			conf.foreground = 1;
451 			break;
452 
453 		case 'f':
454 			config_path = absolutify_path(optarg);
455 			break;
456 
457 		case 'h':
458 			usage();
459 			return 0;
460 
461 		case 'n':
462 			conftest++;
463 			break;
464 
465 		case 'P':
466 			pidfile = optarg;
467 			break;
468 
469 		case 'V':
470 			puts("Version: " GMID_STRING);
471 			return 0;
472 
473 		case 'v':
474 			conf.verbose++;
475 			break;
476 
477 		default:
478 			usage();
479 			return 1;
480 		}
481 	}
482 	argc -= optind;
483 	argv += optind;
484 
485 	if (argc != 0)
486 		usage();
487 
488 	parse_conf(config_path);
489 
490 	if (conftest) {
491 		fprintf(stderr, "config OK\n");
492 		if (conftest > 1)
493 			print_conf();
494 		return 0;
495 	}
496 
497 	if (!conf.foreground) {
498 		/* log to syslog */
499 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
500 		imsg_flush(&logibuf);
501 
502 		if (daemon(1, 1) == -1)
503 			fatal("daemon: %s", strerror(errno));
504 	}
505 
506 	sock4 = make_socket(conf.port, AF_INET);
507 	sock6 = -1;
508 	if (conf.ipv6)
509 		sock6 = make_socket(conf.port, AF_INET6);
510 
511 	signal(SIGPIPE, SIG_IGN);
512 
513 	pidfd = write_pidfile(pidfile);
514 
515 	/*
516 	 * Linux seems to call the event handlers even when we're
517 	 * doing a sigwait.  These dummy handlers are here to avoid
518 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
519 	 */
520 	signal(SIGHUP, dummy_handler);
521 	signal(SIGINT, dummy_handler);
522 	signal(SIGTERM, dummy_handler);
523 
524 	/* wait a sighup and reload the daemon */
525 	for (;;) {
526 		serve();
527 
528 		if (!wait_signal())
529 			break;
530 
531 		log_info(NULL, "reloading configuration %s", config_path);
532 
533 		/* close the servers */
534 		for (i = 0; i < conf.prefork; ++i) {
535 			imsg_compose(&servibuf[i], IMSG_QUIT, 0, 0, -1, NULL, 0);
536 			imsg_flush(&servibuf[i]);
537 			close(servibuf[i].fd);
538 		}
539 
540 		old_ipv6 = conf.ipv6;
541 		old_port = conf.port;
542 
543 		free_config();
544 		init_config();
545 		parse_conf(config_path);
546 
547 		if (old_port != conf.port) {
548 			close(sock4);
549 			close(sock6);
550 			sock4 = -1;
551 			sock6 = -1;
552 		}
553 
554 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
555 			close(sock6);
556 			sock6 = -1;
557 		}
558 
559 		if (sock4 == -1)
560 			sock4 = make_socket(conf.port, AF_INET);
561 		if (sock6 == -1 && conf.ipv6)
562 			sock6 = make_socket(conf.port, AF_INET6);
563 	}
564 
565 	imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
566 	imsg_flush(&exibuf);
567 
568 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
569 	imsg_flush(&logibuf);
570 
571 	if (pidfd != -1)
572 		close(pidfd);
573 
574 	return 0;
575 }