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 <grp.h>
27 #include <pwd.h>
28 #include <signal.h>
29 #include <string.h>
30 
31 static const char	*opts = "D:df:hnP:Vv";
32 
33 static const struct option longopts[] = {
34 	{"help",	no_argument,		NULL,	'h'},
35 	{"version",	no_argument,		NULL,	'V'},
36 	{NULL,		0,			NULL,	0},
37 };
38 
39 struct fcgi fcgi[FCGI_MAX];
40 
41 struct vhosthead hosts;
42 
43 int sock4, sock6;
44 
45 struct imsgbuf logibuf, servibuf[PROC_MAX];
46 
47 const char *config_path = "/etc/gmid.conf";
48 const char *pidfile;
49 
50 struct conf conf;
51 
52 struct tls_config *tlsconf;
53 struct tls *ctx;
54 
55 static void
56 dummy_handler(int signo)
57 {
58 	return;
59 }
60 
61 void
62 load_vhosts(void)
63 {
64 	struct vhost	*h;
65 	struct location	*l;
66 
67 	TAILQ_FOREACH(h, &hosts, vhosts) {
68 		TAILQ_FOREACH(l, &h->locations, locations) {
69 			if (*l->dir == '\0')
70 				continue;
71 			if ((l->dirfd = open(l->dir, O_RDONLY | O_DIRECTORY)) == -1)
72 				fatal("open %s for domain %s: %s", l->dir, h->domain,
73 				    strerror(errno));
74 		}
75 	}
76 }
77 
78 int
79 make_socket(int port, int family)
80 {
81 	int sock, v;
82 	struct sockaddr_in addr4;
83 	struct sockaddr_in6 addr6;
84 	struct sockaddr *addr;
85 	socklen_t len;
86 
87 	switch (family) {
88 	case AF_INET:
89 		memset(&addr4, 0, sizeof(addr4));
90 		addr4.sin_family = family;
91 		addr4.sin_port = htons(port);
92 		addr4.sin_addr.s_addr = INADDR_ANY;
93 		addr = (struct sockaddr*)&addr4;
94 		len = sizeof(addr4);
95 		break;
96 
97 	case AF_INET6:
98 		memset(&addr6, 0, sizeof(addr6));
99 		addr6.sin6_family = AF_INET6;
100 		addr6.sin6_port = htons(port);
101 		addr6.sin6_addr = in6addr_any;
102 		addr = (struct sockaddr*)&addr6;
103 		len = sizeof(addr6);
104 		break;
105 
106 	default:
107 		/* unreachable */
108 		abort();
109 	}
110 
111 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
112 		fatal("socket: %s", strerror(errno));
113 
114 	v = 1;
115 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
116 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
117 
118 	v = 1;
119 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
120 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
121 
122 	mark_nonblock(sock);
123 
124 	if (bind(sock, addr, len) == -1)
125 		fatal("bind: %s", strerror(errno));
126 
127 	if (listen(sock, 16) == -1)
128 		fatal("listen: %s", strerror(errno));
129 
130 	return sock;
131 }
132 
133 static void
134 add_keypair(struct vhost *h)
135 {
136 	if (*h->ocsp == '\0') {
137 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
138 			fatal("failed to load the keypair (%s, %s)",
139 			    h->cert, h->key);
140 	} else {
141 		if (tls_config_add_keypair_ocsp_file(tlsconf, h->cert, h->key,
142 		    h->ocsp) == -1)
143 			fatal("failed to load the keypair (%s, %s, %s)",
144 			    h->cert, h->key, h->ocsp);
145 	}
146 }
147 
148 void
149 setup_tls(void)
150 {
151 	struct vhost *h;
152 
153 	if ((tlsconf = tls_config_new()) == NULL)
154 		fatal("tls_config_new");
155 
156 	/* optionally accept client certs, but don't try to verify them */
157 	tls_config_verify_client_optional(tlsconf);
158 	tls_config_insecure_noverifycert(tlsconf);
159 
160 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
161 		fatal("tls_config_set_protocols");
162 
163 	if ((ctx = tls_server()) == NULL)
164 		fatal("tls_server failure");
165 
166 	h = TAILQ_FIRST(&hosts);
167 
168 	/* we need to set something, then we can add how many key we want */
169 	if (tls_config_set_keypair_file(tlsconf, h->cert, h->key))
170 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
171 		    h->cert, h->key);
172 
173 	/* same for OCSP */
174 	if (*h->ocsp != '\0' &&
175 	    tls_config_set_ocsp_staple_file(tlsconf, h->ocsp) == -1)
176 		fatal("tls_config_set_ocsp_staple_file failed for (%s)",
177 		    h->ocsp);
178 
179 	while ((h = TAILQ_NEXT(h, vhosts)) != NULL)
180 		add_keypair(h);
181 
182 	if (tls_configure(ctx, tlsconf) == -1)
183 		fatal("tls_configure: %s", tls_error(ctx));
184 }
185 
186 static int
187 listener_main(struct imsgbuf *ibuf)
188 {
189 	drop_priv();
190 	if (load_default_mime(&conf.mime) == -1)
191 		fatal("load_default_mime: %s", strerror(errno));
192 	sort_mime(&conf.mime);
193 	load_vhosts();
194 	loop(ctx, sock4, sock6, ibuf);
195 	return 0;
196 }
197 
198 void
199 init_config(void)
200 {
201 	TAILQ_INIT(&hosts);
202 
203 	conf.port = 1965;
204 	conf.ipv6 = 0;
205 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
206 
207 	init_mime(&conf.mime);
208 
209 	conf.prefork = 3;
210 }
211 
212 void
213 free_config(void)
214 {
215 	struct vhost *h, *th;
216 	struct location *l, *tl;
217 	struct proxy *p, *tp;
218 	struct envlist *e, *te;
219 	struct alist *a, *ta;
220 	int v;
221 
222 	v = conf.verbose;
223 
224 	free_mime(&conf.mime);
225 	memset(&conf, 0, sizeof(conf));
226 
227 	conf.verbose = v;
228 
229 	TAILQ_FOREACH_SAFE(h, &hosts, vhosts, th) {
230 		TAILQ_FOREACH_SAFE(l, &h->locations, locations, tl) {
231 			TAILQ_REMOVE(&h->locations, l, locations);
232 
233 			if (l->dirfd != -1)
234 				close(l->dirfd);
235 
236 			free(l);
237 		}
238 
239 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
240 			TAILQ_REMOVE(&h->params, e, envs);
241 			free(e);
242 		}
243 
244 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
245 			TAILQ_REMOVE(&h->aliases, a, aliases);
246 			free(a);
247 		}
248 
249 		TAILQ_FOREACH_SAFE(p, &h->proxies, proxies, tp) {
250 			TAILQ_REMOVE(&h->proxies, p, proxies);
251 			tls_unload_file(p->cert, p->certlen);
252 			tls_unload_file(p->key, p->keylen);
253 			free(p);
254 		}
255 
256 		TAILQ_REMOVE(&hosts, h, vhosts);
257 		free(h);
258 	}
259 
260 	memset(fcgi, 0, sizeof(fcgi));
261 
262 	tls_free(ctx);
263 	tls_config_free(tlsconf);
264 }
265 
266 static int
267 wait_signal(void)
268 {
269 	sigset_t mask;
270 	int signo;
271 
272 	sigemptyset(&mask);
273 	sigaddset(&mask, SIGHUP);
274 	sigaddset(&mask, SIGINT);
275 	sigaddset(&mask, SIGTERM);
276 	sigwait(&mask, &signo);
277 
278 	return signo == SIGHUP;
279 }
280 
281 void
282 drop_priv(void)
283 {
284 	struct passwd *pw = NULL;
285 
286 	if (*conf.chroot != '\0' && *conf.user == '\0')
287 		fatal("can't chroot without an user to switch to after.");
288 
289 	if (*conf.user != '\0') {
290 		if ((pw = getpwnam(conf.user)) == NULL)
291 			fatal("can't find user %s", conf.user);
292 	}
293 
294 	if (*conf.chroot != '\0') {
295 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
296 			fatal("%s: %s", conf.chroot, strerror(errno));
297 	}
298 
299 	if (pw != NULL) {
300 		if (setgroups(1, &pw->pw_gid) == -1 ||
301 		    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1 ||
302 		    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
303 			fatal("cannot drop privileges");
304 	}
305 
306 	if (getuid() == 0)
307 		log_warn(NULL, "not a good idea to run a network daemon as root");
308 }
309 
310 static void
311 usage(void)
312 {
313 	fprintf(stderr,
314 	    "Version: " GMID_STRING "\n"
315 	    "Usage: %s [-dhnVv] [-D macro=value] [-f config] [-P pidfile]\n",
316 	    getprogname());
317 }
318 
319 static void
320 logger_init(void)
321 {
322 	int p[2];
323 
324 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
325 		err(1, "socketpair");
326 
327 	switch (fork()) {
328 	case -1:
329 		err(1, "fork");
330 	case 0:
331 		signal(SIGHUP, SIG_IGN);
332 		close(p[0]);
333 		setproctitle("logger");
334 		imsg_init(&logibuf, p[1]);
335 		drop_priv();
336 		_exit(logger_main(p[1], &logibuf));
337 	default:
338 		close(p[1]);
339 		imsg_init(&logibuf, p[0]);
340 		return;
341 	}
342 }
343 
344 static void
345 serve(void)
346 {
347 	int i, p[2];
348 
349 	/* setup tls before dropping privileges: we don't want user
350 	 * to put private certs inside the chroot. */
351 	setup_tls();
352 
353 	for (i = 0; i < conf.prefork; ++i) {
354 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
355 		    PF_UNSPEC, p) == -1)
356 			fatal("socketpair: %s", strerror(errno));
357 
358 		switch (fork()) {
359 		case -1:
360 			fatal("fork: %s", strerror(errno));
361 		case 0:		/* child */
362 			close(p[0]);
363 			imsg_init(&servibuf[i], p[1]);
364 			setproctitle("server");
365 			_exit(listener_main(&servibuf[i]));
366 		default:
367 			close(p[1]);
368 			imsg_init(&servibuf[i], p[0]);
369 		}
370 	}
371 }
372 
373 static int
374 write_pidfile(const char *pidfile)
375 {
376 	struct flock	lock;
377 	int		fd;
378 
379 	if (pidfile == NULL)
380 		return -1;
381 
382 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
383 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
384 
385 	lock.l_start = 0;
386 	lock.l_len = 0;
387 	lock.l_type = F_WRLCK;
388 	lock.l_whence = SEEK_SET;
389 
390 	if (fcntl(fd, F_SETLK, &lock) == -1)
391 		fatal("can't lock %s, gmid is already running?", pidfile);
392 
393 	if (ftruncate(fd, 0) == -1)
394 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
395 
396 	dprintf(fd, "%d\n", getpid());
397 
398 	return fd;
399 }
400 
401 int
402 main(int argc, char **argv)
403 {
404 	int i, ch, conftest = 0;
405 	int pidfd, old_ipv6, old_port;
406 
407 	logger_init();
408 	init_config();
409 
410 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
411 		switch (ch) {
412 		case 'D':
413 			if (cmdline_symset(optarg) == -1)
414 				fatal("could not parse macro definition: %s",
415 				    optarg);
416 			break;
417 		case 'd':
418 			conf.foreground = 1;
419 			break;
420 		case 'f':
421 			config_path = absolutify_path(optarg);
422 			break;
423 		case 'h':
424 			usage();
425 			return 0;
426 		case 'n':
427 			conftest++;
428 			break;
429 		case 'P':
430 			pidfile = optarg;
431 			break;
432 		case 'V':
433 			puts("Version: " GMID_STRING);
434 			return 0;
435 		case 'v':
436 			conf.verbose++;
437 			break;
438 		default:
439 			usage();
440 			return 1;
441 		}
442 	}
443 	argc -= optind;
444 	argv += optind;
445 
446 	if (argc != 0)
447 		usage();
448 
449 	parse_conf(config_path);
450 
451 	if (conftest) {
452 		fprintf(stderr, "config OK\n");
453 		if (conftest > 1)
454 			print_conf();
455 		return 0;
456 	}
457 
458 	if (!conf.foreground) {
459 		/* log to syslog */
460 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
461 		imsg_flush(&logibuf);
462 
463 		if (daemon(1, 1) == -1)
464 			fatal("daemon: %s", strerror(errno));
465 	}
466 
467 	sock4 = make_socket(conf.port, AF_INET);
468 	sock6 = -1;
469 	if (conf.ipv6)
470 		sock6 = make_socket(conf.port, AF_INET6);
471 
472 	signal(SIGPIPE, SIG_IGN);
473 
474 	pidfd = write_pidfile(pidfile);
475 
476 	/*
477 	 * Linux seems to call the event handlers even when we're
478 	 * doing a sigwait.  These dummy handlers are here to avoid
479 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
480 	 */
481 	signal(SIGHUP, dummy_handler);
482 	signal(SIGINT, dummy_handler);
483 	signal(SIGTERM, dummy_handler);
484 
485 	/* wait a sighup and reload the daemon */
486 	for (;;) {
487 		serve();
488 
489 		if (!wait_signal())
490 			break;
491 
492 		log_info(NULL, "reloading configuration %s", config_path);
493 
494 		/* close the servers */
495 		for (i = 0; i < conf.prefork; ++i) {
496 			imsg_compose(&servibuf[i], IMSG_QUIT, 0, 0, -1, NULL, 0);
497 			imsg_flush(&servibuf[i]);
498 			close(servibuf[i].fd);
499 		}
500 
501 		old_ipv6 = conf.ipv6;
502 		old_port = conf.port;
503 
504 		free_config();
505 		init_config();
506 		parse_conf(config_path);
507 
508 		if (old_port != conf.port) {
509 			close(sock4);
510 			close(sock6);
511 			sock4 = -1;
512 			sock6 = -1;
513 		}
514 
515 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
516 			close(sock6);
517 			sock6 = -1;
518 		}
519 
520 		if (sock4 == -1)
521 			sock4 = make_socket(conf.port, AF_INET);
522 		if (sock6 == -1 && conf.ipv6)
523 			sock6 = make_socket(conf.port, AF_INET6);
524 	}
525 
526 	for (i = 0; i < conf.prefork; ++i) {
527 		imsg_compose(&servibuf[i], IMSG_QUIT, 0, 0, -1, NULL, 0);
528 		imsg_flush(&servibuf[i]);
529 		close(servibuf[i].fd);
530 	}
531 
532 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
533 	imsg_flush(&logibuf);
534 	close(logibuf.fd);
535 
536 	if (pidfd != -1)
537 		close(pidfd);
538 
539 	return 0;
540 }