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 <limits.h>
24 #include <pwd.h>
25 #include <signal.h>
26 #include <string.h>
27 
28 struct vhost hosts[HOSTSLEN];
29 
30 int sock4, sock6;
31 
32 struct imsgbuf logibuf, exibuf, servibuf[PROC_MAX];
33 
34 const char *config_path, *certs_dir, *hostname;
35 
36 struct conf conf;
37 
38 struct tls_config *tlsconf;
39 struct tls *ctx;
40 
41 /* XXX: create recursively */
42 void
43 mkdirs(const char *path)
44 {
45 	if (mkdir(path, 0755) == -1 && errno != EEXIST)
46 		fatal("can't mkdir %s: %s", path, strerror(errno));
47 }
48 
49 /* $XDG_DATA_HOME/gmid */
50 char *
51 data_dir(void)
52 {
53 	const char *home, *xdg;
54 	char *t;
55 
56 	if ((xdg = getenv("XDG_DATA_HOME")) == NULL) {
57 		if ((home = getenv("HOME")) == NULL)
58 			errx(1, "XDG_DATA_HOME and HOME both empty");
59 		if (asprintf(&t, "%s/.local/share/gmid", home) == -1)
60 			err(1, "asprintf");
61 		mkdirs(t);
62 		return t;
63 	}
64 
65 	if (asprintf(&t, "%s/gmid", xdg) == -1)
66 		err(1, "asprintf");
67 	mkdirs(t);
68 	return t;
69 }
70 
71 void
72 load_local_cert(const char *hostname, const char *dir)
73 {
74 	char *cert, *key;
75 
76 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
77 		errx(1, "asprintf");
78 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
79 		errx(1, "asprintf");
80 
81 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
82 		gen_certificate(hostname, cert, key);
83 
84 	hosts[0].cert = cert;
85 	hosts[0].key = key;
86 	hosts[0].domain = hostname;
87 }
88 
89 void
90 load_vhosts(void)
91 {
92 	struct vhost *h;
93 
94 	for (h = hosts; h->domain != NULL; ++h) {
95 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
96 			fatal("open %s for domain %s", h->dir, h->domain);
97 	}
98 }
99 
100 int
101 make_socket(int port, int family)
102 {
103 	int sock, v;
104 	struct sockaddr_in addr4;
105 	struct sockaddr_in6 addr6;
106 	struct sockaddr *addr;
107 	socklen_t len;
108 
109         switch (family) {
110 	case AF_INET:
111 		bzero(&addr4, sizeof(addr4));
112 		addr4.sin_family = family;
113 		addr4.sin_port = htons(port);
114 		addr4.sin_addr.s_addr = INADDR_ANY;
115 		addr = (struct sockaddr*)&addr4;
116 		len = sizeof(addr4);
117 		break;
118 
119 	case AF_INET6:
120 		bzero(&addr6, sizeof(addr6));
121 		addr6.sin6_family = AF_INET6;
122 		addr6.sin6_port = htons(port);
123 		addr6.sin6_addr = in6addr_any;
124 		addr = (struct sockaddr*)&addr6;
125 		len = sizeof(addr6);
126 		break;
127 
128 	default:
129 		/* unreachable */
130 		abort();
131 	}
132 
133 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
134 		fatal("socket: %s", strerror(errno));
135 
136 	v = 1;
137 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
138 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
139 
140 	v = 1;
141 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
142 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
143 
144 	mark_nonblock(sock);
145 
146 	if (bind(sock, addr, len) == -1)
147 		fatal("bind: %s", strerror(errno));
148 
149 	if (listen(sock, 16) == -1)
150 		fatal("listen: %s", strerror(errno));
151 
152 	return sock;
153 }
154 
155 void
156 setup_tls(void)
157 {
158 	struct vhost *h;
159 
160 	if ((tlsconf = tls_config_new()) == NULL)
161 		fatal("tls_config_new");
162 
163 	/* optionally accept client certs, but don't try to verify them */
164 	tls_config_verify_client_optional(tlsconf);
165 	tls_config_insecure_noverifycert(tlsconf);
166 
167 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
168 		fatal("tls_config_set_protocols");
169 
170 	if ((ctx = tls_server()) == NULL)
171 		fatal("tls_server failure");
172 
173 	/* we need to set something, then we can add how many key we want */
174 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
175 		fatal("tls_config_set_keypair_file failed for (%s, %s)",
176 		    hosts->cert, hosts->key);
177 
178 	for (h = &hosts[1]; h->domain != NULL; ++h) {
179 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
180 			fatal("failed to load the keypair (%s, %s)",
181 			    h->cert, h->key);
182 	}
183 
184 	if (tls_configure(ctx, tlsconf) == -1)
185 		fatal("tls_configure: %s", tls_error(ctx));
186 }
187 
188 static int
189 listener_main(struct imsgbuf *ibuf)
190 {
191 	drop_priv();
192 	load_default_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 	size_t i;
202 
203 	bzero(hosts, sizeof(hosts));
204 	for (i = 0; i < HOSTSLEN; ++i)
205 		hosts[i].dirfd = -1;
206 
207 	conf.port = 1965;
208 	conf.ipv6 = 0;
209 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
210 
211 	init_mime(&conf.mime);
212 
213 	conf.chroot = NULL;
214 	conf.user = NULL;
215 
216 	/* we'll change this to 0 when running without config. */
217 	conf.prefork = 3;
218 }
219 
220 void
221 free_config(void)
222 {
223 	struct vhost *h;
224 	struct location *l;
225 
226 	free(conf.chroot);
227 	free(conf.user);
228 	memset(&conf, 0, sizeof(conf));
229 
230 	for (h = hosts; h->domain != NULL; ++h) {
231 		free((char*)h->domain);
232 		free((char*)h->cert);
233 		free((char*)h->key);
234 		free((char*)h->dir);
235 		free((char*)h->cgi);
236 		free((char*)h->entrypoint);
237 
238 		for (l = h->locations; l->match != NULL; ++l) {
239 			free((char*)l->match);
240 			free((char*)l->lang);
241 			free((char*)l->default_mime);
242 			free((char*)l->index);
243 			free((char*)l->block_fmt);
244 		}
245 	}
246 	memset(hosts, 0, sizeof(hosts));
247 
248 	tls_free(ctx);
249 	tls_config_free(tlsconf);
250 }
251 
252 static void
253 wait_sighup(void)
254 {
255 	sigset_t mask;
256 	int signo;
257 
258 	sigemptyset(&mask);
259 	sigaddset(&mask, SIGHUP);
260 	sigwait(&mask, &signo);
261 }
262 
263 void
264 drop_priv(void)
265 {
266 	struct passwd *pw = NULL;
267 
268 	if (conf.chroot != NULL && conf.user == NULL)
269 		fatal("can't chroot without an user to switch to after.");
270 
271 	if (conf.user != NULL) {
272 		if ((pw = getpwnam(conf.user)) == NULL)
273 			fatal("can't find user %s", conf.user);
274 	}
275 
276 	if (conf.chroot != NULL) {
277 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
278 			fatal("%s: %s", conf.chroot, strerror(errno));
279 	}
280 
281 	if (pw != NULL) {
282 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
283 			fatal("setresuid(%d): %s", pw->pw_uid,
284 			    strerror(errno));
285 	}
286 
287 	if (getuid() == 0)
288 		log_warn(NULL, "not a good idea to run a network daemon as root");
289 }
290 
291 static void
292 usage(const char *me)
293 {
294 	fprintf(stderr,
295 	    "USAGE: %s [-fn] [-c config] | [-6h] [-d certs-dir] [-H host]\n"
296 	    "       [-p port] [-x cgi] [dir]\n",
297 	    me);
298 }
299 
300 static void
301 logger_init(void)
302 {
303 	int p[2];
304 
305 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
306 		err(1, "socketpair");
307 
308 	switch (fork()) {
309 	case -1:
310 		err(1, "fork");
311 	case 0:
312 		signal(SIGHUP, SIG_IGN);
313 		close(p[0]);
314 		setproctitle("logger");
315 		imsg_init(&logibuf, p[1]);
316 		drop_priv();
317 		_exit(logger_main(p[1], &logibuf));
318 	default:
319 		close(p[1]);
320 		imsg_init(&logibuf, p[0]);
321 		return;
322 	}
323 }
324 
325 static int
326 serve(int argc, char **argv, struct imsgbuf *ibuf)
327 {
328 	char	path[PATH_MAX];
329 	int	i, p[2];
330 
331         if (config_path == NULL) {
332 		if (hostname == NULL)
333 			hostname = "localhost";
334 		if (certs_dir == NULL)
335 			certs_dir = data_dir();
336 		load_local_cert(hostname, certs_dir);
337 
338 		hosts[0].domain = "*";
339 		hosts[0].locations[0].auto_index = 1;
340 		hosts[0].locations[0].match = "*";
341 
342 		switch (argc) {
343 		case 0:
344 			hosts[0].dir = getcwd(path, sizeof(path));
345 			break;
346 		case 1:
347 			hosts[0].dir = absolutify_path(argv[0]);
348 			break;
349 		default:
350 			usage(getprogname());
351 			return 1;
352 		}
353 
354 		log_notice(NULL, "serving %s on port %d", hosts[0].dir, conf.port);
355 	}
356 
357 	/* setup tls before dropping privileges: we don't want user
358 	 * to put private certs inside the chroot. */
359 	setup_tls();
360 
361 	for (i = 0; i < conf.prefork; ++i) {
362 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
363 		    PF_UNSPEC, p) == -1)
364 			fatal("socketpair: %s", strerror(errno));
365 
366 		switch (fork()) {
367 		case -1:
368 			fatal("fork: %s", strerror(errno));
369 		case 0:		/* child */
370 			close(p[0]);
371 			imsg_init(&exibuf, p[1]);
372 			setproctitle("server");
373 			_exit(listener_main(&exibuf));
374 		default:
375 			close(p[1]);
376 			imsg_init(&servibuf[i], p[0]);
377 		}
378 	}
379 
380 	setproctitle("executor");
381 	drop_priv();
382 	_exit(executor_main(ibuf));
383 }
384 
385 int
386 main(int argc, char **argv)
387 {
388 	int ch, conftest = 0, configless = 0;
389 	int old_ipv6, old_port;
390 
391 	init_config();
392 
393 	while ((ch = getopt(argc, argv, "6c:d:fH:hnp:vx:")) != -1) {
394 		switch (ch) {
395 		case '6':
396 			conf.ipv6 = 1;
397 			configless = 1;
398 			break;
399 
400 		case 'c':
401 			config_path = absolutify_path(optarg);
402 			break;
403 
404 		case 'd':
405 			certs_dir = optarg;
406 			configless = 1;
407 			break;
408 
409 		case 'f':
410 			conf.foreground = 1;
411 			break;
412 
413 		case 'H':
414 			hostname = optarg;
415 			configless = 1;
416 			break;
417 
418 		case 'h':
419 			usage(*argv);
420 			return 0;
421 
422 		case 'n':
423 			conftest = 1;
424 			break;
425 
426 		case 'p':
427 			conf.port = parse_portno(optarg);
428 			configless = 1;
429 			break;
430 
431 		case 'v':
432 			conf.verbose++;
433 			break;
434 
435 		case 'x':
436 			/* drop the starting / (if any) */
437 			if (*optarg == '/')
438 				optarg++;
439 			hosts[0].cgi = optarg;
440 			configless = 1;
441 			break;
442 
443 		default:
444 			usage(*argv);
445 			return 1;
446 		}
447 	}
448 	argc -= optind;
449 	argv += optind;
450 
451 	if (config_path == NULL) {
452 		configless = 1;
453 		conf.foreground = 1;
454 		conf.prefork = 1;
455 		conf.verbose++;
456 	}
457 
458 	if (config_path != NULL && (argc > 0 || configless))
459 		err(1, "can't specify options in config mode.");
460 
461 	if (conftest) {
462 		parse_conf(config_path);
463 		puts("config OK");
464 		return 0;
465 	}
466 
467 	signal(SIGPIPE, SIG_IGN);
468 	signal(SIGCHLD, SIG_IGN);
469 
470 	if (!conf.foreground && !configless) {
471 		if (daemon(1, 1) == -1)
472 			err(1, "daemon");
473 	}
474 
475 	if (config_path != NULL)
476 		parse_conf(config_path);
477 
478 	logger_init();
479 
480 	sock4 = make_socket(conf.port, AF_INET);
481 	sock6 = -1;
482 	if (conf.ipv6)
483 		sock6 = make_socket(conf.port, AF_INET6);
484 
485 	if (configless) {
486 		serve(argc, argv, NULL);
487 		imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
488 		imsg_flush(&logibuf);
489 		return 0;
490 	}
491 
492 	/* wait a sighup and reload the daemon */
493 	for (;;) {
494 		struct imsgbuf exibuf;
495 		int p[2];
496 
497 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
498 		    PF_UNSPEC, p) == -1)
499 			fatal("socketpair: %s", strerror(errno));
500 
501 		switch (fork()) {
502 		case -1:
503 			fatal("fork: %s", strerror(errno));
504 		case 0:
505 			signal(SIGHUP, SIG_IGN);
506 			close(p[0]);
507 			imsg_init(&exibuf, p[1]);
508 			_exit(serve(argc, argv, &exibuf));
509 		}
510 
511 		close(p[1]);
512 		imsg_init(&exibuf, p[0]);
513 
514 		wait_sighup();
515 		log_info(NULL, "reloading configuration %s", config_path);
516 
517 		/* close the executor (it'll close the servers too) */
518 		imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
519 		imsg_flush(&exibuf);
520 		close(p[0]);
521 
522 		old_ipv6 = conf.ipv6;
523 		old_port = conf.port;
524 
525 		free_config();
526 		init_config();
527 		parse_conf(config_path);
528 
529 		if (old_port != conf.port) {
530 			close(sock4);
531 			close(sock6);
532 			sock4 = -1;
533 			sock6 = -1;
534 		}
535 
536 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
537 			close(sock6);
538 			sock6 = -1;
539 		}
540 
541 		if (sock4 == -1)
542 			sock4 = make_socket(conf.port, AF_INET);
543 		if (sock6 == -1 && conf.ipv6)
544 			sock6 = make_socket(conf.port, AF_INET6);
545 	}
546 }