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Date:: Sat Sep 10 09:21:09 2022 UTC
Message:: make config fields `chroot' and `user' fixed-size
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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 (!conf.mime.skip_defaults && 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->env, envs, te) {
246 			TAILQ_REMOVE(&h->env, e, envs);
247 
248 			free(e->name);
249 			free(e->value);
250 			free(e);
251 		}
252 
253 		TAILQ_FOREACH_SAFE(e, &h->params, envs, te) {
254 			TAILQ_REMOVE(&h->params, e, envs);
255 
256 			free(e->name);
257 			free(e->value);
258 			free(e);
259 		}
260 
261 		TAILQ_FOREACH_SAFE(a, &h->aliases, aliases, ta) {
262 			TAILQ_REMOVE(&h->aliases, a, aliases);
263 
264 			free(a->alias);
265 			free(a);
266 		}
267 
268 		TAILQ_FOREACH_SAFE(p, &h->proxies, proxies, tp) {
269 			TAILQ_REMOVE(&h->proxies, p, proxies);
270 
271 			free(p->match_proto);
272 			free(p->match_host);
273 			free(p->host);
274 			free(p->sni);
275 			tls_unload_file(p->cert, p->certlen);
276 			tls_unload_file(p->key, p->keylen);
277 			free(p);
278 		}
279 
280 		free((char*)h->domain);
281 		free((char*)h->cert);
282 		free((char*)h->key);
283 		free((char*)h->ocsp);
284 		free((char*)h->entrypoint);
285 
286 		TAILQ_REMOVE(&hosts, h, vhosts);
287 		free(h);
288 	}
289 
290 	for (i = 0; i < FCGI_MAX; ++i) {
291 		if (fcgi[i].path == NULL && fcgi[i].prog == NULL)
292 			break;
293 		free(fcgi[i].path);
294 		free(fcgi[i].port);
295 		free(fcgi[i].prog);
296 
297 		fcgi[i].path = NULL;
298 		fcgi[i].port = NULL;
299 		fcgi[i].prog = NULL;
300 	}
301 
302 	tls_free(ctx);
303 	tls_config_free(tlsconf);
304 }
305 
306 static int
307 wait_signal(void)
308 {
309 	sigset_t mask;
310 	int signo;
311 
312 	sigemptyset(&mask);
313 	sigaddset(&mask, SIGHUP);
314 	sigaddset(&mask, SIGINT);
315 	sigaddset(&mask, SIGTERM);
316 	sigwait(&mask, &signo);
317 
318 	return signo == SIGHUP;
319 }
320 
321 void
322 drop_priv(void)
323 {
324 	struct passwd *pw = NULL;
325 
326 	if (*conf.chroot != '\0' && *conf.user == '\0')
327 		fatal("can't chroot without an user to switch to after.");
328 
329 	if (*conf.user != '\0') {
330 		if ((pw = getpwnam(conf.user)) == NULL)
331 			fatal("can't find user %s", conf.user);
332 	}
333 
334 	if (*conf.chroot != '\0') {
335 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
336 			fatal("%s: %s", conf.chroot, strerror(errno));
337 	}
338 
339 	if (pw != NULL) {
340 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
341 			fatal("setresuid(%d): %s", pw->pw_uid,
342 			    strerror(errno));
343 	}
344 
345 	if (getuid() == 0)
346 		log_warn(NULL, "not a good idea to run a network daemon as root");
347 }
348 
349 static void
350 usage(void)
351 {
352 	fprintf(stderr,
353 	    "Version: " GMID_STRING "\n"
354 	    "Usage: %s [-dhnVv] [-D macro=value] [-f config] [-P pidfile]\n",
355 	    getprogname());
356 }
357 
358 static void
359 logger_init(void)
360 {
361 	int p[2];
362 
363 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
364 		err(1, "socketpair");
365 
366 	switch (fork()) {
367 	case -1:
368 		err(1, "fork");
369 	case 0:
370 		signal(SIGHUP, SIG_IGN);
371 		close(p[0]);
372 		setproctitle("logger");
373 		imsg_init(&logibuf, p[1]);
374 		drop_priv();
375 		_exit(logger_main(p[1], &logibuf));
376 	default:
377 		close(p[1]);
378 		imsg_init(&logibuf, p[0]);
379 		return;
380 	}
381 }
382 
383 static void
384 serve(void)
385 {
386 	int i, p[2];
387 
388 	/* setup tls before dropping privileges: we don't want user
389 	 * to put private certs inside the chroot. */
390 	setup_tls();
391 
392 	for (i = 0; i < conf.prefork; ++i) {
393 		if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
394 		    PF_UNSPEC, p) == -1)
395 			fatal("socketpair: %s", strerror(errno));
396 
397 		switch (fork()) {
398 		case -1:
399 			fatal("fork: %s", strerror(errno));
400 		case 0:		/* child */
401 			close(p[0]);
402 			imsg_init(&exibuf, p[1]);
403 			setproctitle("server");
404 			_exit(listener_main(&exibuf));
405 		default:
406 			close(p[1]);
407 			imsg_init(&servibuf[i], p[0]);
408 		}
409 	}
410 }
411 
412 static int
413 write_pidfile(const char *pidfile)
414 {
415 	struct flock	lock;
416 	int		fd;
417 
418 	if (pidfile == NULL)
419 		return -1;
420 
421 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
422 		fatal("can't open pidfile %s: %s", pidfile, strerror(errno));
423 
424 	lock.l_start = 0;
425 	lock.l_len = 0;
426 	lock.l_type = F_WRLCK;
427 	lock.l_whence = SEEK_SET;
428 
429 	if (fcntl(fd, F_SETLK, &lock) == -1)
430 		fatal("can't lock %s, gmid is already running?", pidfile);
431 
432 	if (ftruncate(fd, 0) == -1)
433 		fatal("ftruncate: %s: %s", pidfile, strerror(errno));
434 
435 	dprintf(fd, "%d\n", getpid());
436 
437 	return fd;
438 }
439 
440 int
441 main(int argc, char **argv)
442 {
443 	int i, ch, conftest = 0;
444 	int pidfd, old_ipv6, old_port;
445 
446 	logger_init();
447 	init_config();
448 
449 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
450 		switch (ch) {
451 		case 'D':
452 			if (cmdline_symset(optarg) == -1)
453 				fatal("could not parse macro definition: %s",
454 				    optarg);
455 			break;
456 
457 		case 'd':
458 			conf.foreground = 1;
459 			break;
460 
461 		case 'f':
462 			config_path = absolutify_path(optarg);
463 			break;
464 
465 		case 'h':
466 			usage();
467 			return 0;
468 
469 		case 'n':
470 			conftest++;
471 			break;
472 
473 		case 'P':
474 			pidfile = optarg;
475 			break;
476 
477 		case 'V':
478 			puts("Version: " GMID_STRING);
479 			return 0;
480 
481 		case 'v':
482 			conf.verbose++;
483 			break;
484 
485 		default:
486 			usage();
487 			return 1;
488 		}
489 	}
490 	argc -= optind;
491 	argv += optind;
492 
493 	if (argc != 0)
494 		usage();
495 
496 	parse_conf(config_path);
497 
498 	if (conftest) {
499 		fprintf(stderr, "config OK\n");
500 		if (conftest > 1)
501 			print_conf();
502 		return 0;
503 	}
504 
505 	if (!conf.foreground) {
506 		/* log to syslog */
507 		imsg_compose(&logibuf, IMSG_LOG_TYPE, 0, 0, -1, NULL, 0);
508 		imsg_flush(&logibuf);
509 
510 		if (daemon(1, 1) == -1)
511 			fatal("daemon: %s", strerror(errno));
512 	}
513 
514 	sock4 = make_socket(conf.port, AF_INET);
515 	sock6 = -1;
516 	if (conf.ipv6)
517 		sock6 = make_socket(conf.port, AF_INET6);
518 
519 	signal(SIGPIPE, SIG_IGN);
520 
521 	pidfd = write_pidfile(pidfile);
522 
523 	/*
524 	 * Linux seems to call the event handlers even when we're
525 	 * doing a sigwait.  These dummy handlers are here to avoid
526 	 * being terminated on SIGHUP, SIGINT or SIGTERM.
527 	 */
528 	signal(SIGHUP, dummy_handler);
529 	signal(SIGINT, dummy_handler);
530 	signal(SIGTERM, dummy_handler);
531 
532 	/* wait a sighup and reload the daemon */
533 	for (;;) {
534 		serve();
535 
536 		if (!wait_signal())
537 			break;
538 
539 		log_info(NULL, "reloading configuration %s", config_path);
540 
541 		/* close the servers */
542 		for (i = 0; i < conf.prefork; ++i) {
543 			imsg_compose(&servibuf[i], IMSG_QUIT, 0, 0, -1, NULL, 0);
544 			imsg_flush(&servibuf[i]);
545 			close(servibuf[i].fd);
546 		}
547 
548 		old_ipv6 = conf.ipv6;
549 		old_port = conf.port;
550 
551 		free_config();
552 		init_config();
553 		parse_conf(config_path);
554 
555 		if (old_port != conf.port) {
556 			close(sock4);
557 			close(sock6);
558 			sock4 = -1;
559 			sock6 = -1;
560 		}
561 
562 		if (sock6 != -1 && old_ipv6 != conf.ipv6) {
563 			close(sock6);
564 			sock6 = -1;
565 		}
566 
567 		if (sock4 == -1)
568 			sock4 = make_socket(conf.port, AF_INET);
569 		if (sock6 == -1 && conf.ipv6)
570 			sock6 = make_socket(conf.port, AF_INET6);
571 	}
572 
573 	imsg_compose(&exibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
574 	imsg_flush(&exibuf);
575 
576 	imsg_compose(&logibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
577 	imsg_flush(&logibuf);
578 
579 	if (pidfd != -1)
580 		close(pidfd);
581 
582 	return 0;
583 }