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