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Date:: Wed Feb 3 16:53:34 2021 UTC
Message:: drop unnecessary check around close
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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 <sys/stat.h>
18 
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <limits.h>
22 #include <limits.h>
23 #include <netdb.h>
24 #include <pwd.h>
25 #include <signal.h>
26 #include <stdarg.h>
27 #include <string.h>
28 
29 #include <openssl/pem.h>
30 #include <openssl/x509.h>
31 
32 #include "gmid.h"
33 
34 struct vhost hosts[HOSTSLEN];
35 
36 int exfd, foreground, verbose, sock4, sock6;
37 
38 const char *config_path, *certs_dir, *hostname;
39 
40 struct conf conf;
41 
42 struct tls *ctx;
43 
44 void
45 fatal(const char *fmt, ...)
46 {
47 	va_list ap;
48 
49 	va_start(ap, fmt);
50 
51 	if (foreground) {
52 		vfprintf(stderr, fmt, ap);
53 		fprintf(stderr, "\n");
54 	} else
55 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
56 
57 	va_end(ap);
58 	exit(1);
59 }
60 
61 void
62 logs(int priority, struct client *c,
63     const char *fmt, ...)
64 {
65 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
66 	char *fmted, *s;
67 	size_t len;
68 	int ec;
69 	va_list ap;
70 
71 	if (foreground && !verbose) {
72 		if (priority == LOG_DEBUG || priority == LOG_INFO)
73 			return;
74 	}
75 
76 	va_start(ap, fmt);
77 
78 	if (c == NULL) {
79 		strncpy(hbuf, "<internal>", sizeof(hbuf));
80 		sbuf[0] = '\0';
81 	} else {
82 		len = sizeof(c->addr);
83 		ec = getnameinfo((struct sockaddr*)&c->addr, len,
84 		    hbuf, sizeof(hbuf),
85 		    sbuf, sizeof(sbuf),
86 		    NI_NUMERICHOST | NI_NUMERICSERV);
87 		if (ec != 0)
88 			fatal("getnameinfo: %s", gai_strerror(ec));
89 	}
90 
91 	if (vasprintf(&fmted, fmt, ap) == -1)
92 		fatal("vasprintf: %s", strerror(errno));
93 
94 	if (foreground)
95 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
96 	else {
97 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
98 			fatal("asprintf: %s", strerror(errno));
99 		syslog(priority | LOG_DAEMON, "%s", s);
100 		free(s);
101 	}
102 
103 	free(fmted);
104 
105 	va_end(ap);
106 }
107 
108 /* strchr, but with a bound */
109 static char *
110 gmid_strnchr(char *s, int c, size_t len)
111 {
112 	size_t i;
113 
114 	for (i = 0; i < len; ++i)
115 		if (s[i] == c)
116 			return &s[i];
117 	return NULL;
118 }
119 
120 void
121 log_request(struct client *c, char *meta, size_t l)
122 {
123 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV], b[GEMINI_URL_LEN];
124 	char *t;
125 	size_t len;
126 	int ec;
127 
128 	len = sizeof(c->addr);
129 	ec = getnameinfo((struct sockaddr*)&c->addr, len,
130 	    hbuf, sizeof(hbuf),
131 	    sbuf, sizeof(sbuf),
132 	    NI_NUMERICHOST | NI_NUMERICSERV);
133 	if (ec != 0)
134 		fatal("getnameinfo: %s", gai_strerror(ec));
135 
136 	if (c->iri.schema != NULL) {
137 		/* serialize the IRI */
138 		strlcpy(b, c->iri.schema, sizeof(b));
139 		strlcat(b, "://", sizeof(b));
140 
141 		/* log the decoded host name, but if it was invalid
142 		 * use the raw one. */
143 		if (*c->domain != '\0')
144 			strlcat(b, c->domain, sizeof(b));
145 		else
146 			strlcat(b, c->iri.host, sizeof(b));
147 
148 		strlcat(b, "/", sizeof(b));
149 		strlcat(b, c->iri.path, sizeof(b)); /* TODO: sanitize UTF8 */
150 		if (*c->iri.query != '\0') {	    /* TODO: sanitize UTF8 */
151 			strlcat(b, "?", sizeof(b));
152 			strlcat(b, c->iri.query, sizeof(b));
153 		}
154 	} else {
155 		strlcpy(b, c->req, sizeof(b));
156 	}
157 
158 	if ((t = gmid_strnchr(meta, '\r', l)) == NULL)
159 		t = meta + len;
160 
161 	if (foreground)
162 		fprintf(stderr, "%s:%s GET %s %.*s\n", hbuf, sbuf, b,
163 		    (int)(t - meta), meta);
164 	else
165 		syslog(LOG_INFO | LOG_DAEMON, "%s:%s GET %s %.*s",
166 		    hbuf, sbuf, b, (int)(t - meta), meta);
167 }
168 
169 void
170 sig_handler(int sig)
171 {
172 	(void)sig;
173 }
174 
175 void
176 gen_certificate(const char *host, const char *certpath, const char *keypath)
177 {
178 	BIGNUM		e;
179 	EVP_PKEY	*pkey;
180 	RSA		*rsa;
181 	X509		*x509;
182 	X509_NAME	*name;
183 	FILE		*f;
184 	const char	*org = "gmid";
185 
186 	LOGN(NULL, "generating new certificate for %s (it could take a while)",
187 	    host);
188 
189 	if ((pkey = EVP_PKEY_new()) == NULL)
190                 fatal("couldn't create a new private key");
191 
192 	if ((rsa = RSA_new()) == NULL)
193 		fatal("could'nt generate rsa");
194 
195 	BN_init(&e);
196 	BN_set_word(&e, 17);
197 	if (!RSA_generate_key_ex(rsa, 4096, &e, NULL))
198 		fatal("couldn't generate a rsa key");
199 
200 	if (!EVP_PKEY_assign_RSA(pkey, rsa))
201 		fatal("couldn't assign the key");
202 
203 	if ((x509 = X509_new()) == NULL)
204 		fatal("couldn't generate the X509 certificate");
205 
206 	ASN1_INTEGER_set(X509_get_serialNumber(x509), 1);
207 	X509_gmtime_adj(X509_get_notBefore(x509), 0);
208 	X509_gmtime_adj(X509_get_notAfter(x509), 315360000L); /* 10 years */
209 
210 	if (!X509_set_pubkey(x509, pkey))
211 		fatal("couldn't set the public key");
212 
213 	name = X509_get_subject_name(x509);
214 	if (!X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, org, -1, -1, 0))
215 		fatal("couldn't add N to cert");
216 	if (!X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, host, -1, -1, 0))
217 		fatal("couldn't add CN to cert");
218 	X509_set_issuer_name(x509, name);
219 
220 	if (!X509_sign(x509, pkey, EVP_sha256()))
221                 fatal("couldn't sign the certificate");
222 
223 	if ((f = fopen(keypath, "w")) == NULL)
224 		fatal("fopen(%s): %s", keypath, strerror(errno));
225 	if (!PEM_write_PrivateKey(f, pkey, NULL, NULL, 0, NULL, NULL))
226 		fatal("couldn't write private key");
227 	fclose(f);
228 
229 	if ((f = fopen(certpath, "w")) == NULL)
230 		fatal("fopen(%s): %s", certpath, strerror(errno));
231 	if (!PEM_write_X509(f, x509))
232 		fatal("couldn't write cert");
233 	fclose(f);
234 
235 	X509_free(x509);
236 	RSA_free(rsa);
237 }
238 
239 /* XXX: create recursively */
240 void
241 mkdirs(const char *path)
242 {
243 	if (mkdir(path, 0755) == -1 && errno != EEXIST)
244 		fatal("can't mkdir %s: %s", path, strerror(errno));
245 }
246 
247 /* $XDG_DATA_HOME/gmid */
248 char *
249 data_dir(void)
250 {
251 	const char *home, *xdg;
252 	char *t;
253 
254 	if ((xdg = getenv("XDG_DATA_HOME")) == NULL) {
255 		if ((home = getenv("HOME")) == NULL)
256 			errx(1, "XDG_DATA_HOME and HOME both empty");
257 		if (asprintf(&t, "%s/.local/share/gmid", home) == -1)
258 			err(1, "asprintf");
259 		mkdirs(t);
260 		return t;
261 	}
262 
263 	if (asprintf(&t, "%s/gmid", xdg) == -1)
264 		err(1, "asprintf");
265 	mkdirs(t);
266 	return t;
267 }
268 
269 void
270 load_local_cert(const char *hostname, const char *dir)
271 {
272 	char *cert, *key;
273 
274 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
275 		errx(1, "asprintf");
276 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
277 		errx(1, "asprintf");
278 
279 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
280 		gen_certificate(hostname, cert, key);
281 
282 	hosts[0].cert = cert;
283 	hosts[0].key = key;
284 	hosts[0].domain = hostname;
285 }
286 
287 void
288 load_vhosts(void)
289 {
290 	struct vhost *h;
291 
292 	for (h = hosts; h->domain != NULL; ++h) {
293 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
294 			fatal("open %s for domain %s", h->dir, h->domain);
295 	}
296 }
297 
298 int
299 make_socket(int port, int family)
300 {
301 	int sock, v;
302 	struct sockaddr_in addr4;
303 	struct sockaddr_in6 addr6;
304 	struct sockaddr *addr;
305 	socklen_t len;
306 
307         switch (family) {
308 	case AF_INET:
309 		bzero(&addr4, sizeof(addr4));
310 		addr4.sin_family = family;
311 		addr4.sin_port = htons(port);
312 		addr4.sin_addr.s_addr = INADDR_ANY;
313 		addr = (struct sockaddr*)&addr4;
314 		len = sizeof(addr4);
315 		break;
316 
317 	case AF_INET6:
318 		bzero(&addr6, sizeof(addr6));
319 		addr6.sin6_family = AF_INET6;
320 		addr6.sin6_port = htons(port);
321 		addr6.sin6_addr = in6addr_any;
322 		addr = (struct sockaddr*)&addr6;
323 		len = sizeof(addr6);
324 		break;
325 
326 	default:
327 		/* unreachable */
328 		abort();
329 	}
330 
331 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
332 		fatal("socket: %s", strerror(errno));
333 
334 	v = 1;
335 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
336 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
337 
338 	v = 1;
339 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
340 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
341 
342 	mark_nonblock(sock);
343 
344 	if (bind(sock, addr, len) == -1)
345 		fatal("bind: %s", strerror(errno));
346 
347 	if (listen(sock, 16) == -1)
348 		fatal("listen: %s", strerror(errno));
349 
350 	return sock;
351 }
352 
353 void
354 setup_tls(void)
355 {
356 	struct tls_config *tlsconf;
357 	struct vhost *h;
358 
359 	if ((tlsconf = tls_config_new()) == NULL)
360 		fatal("tls_config_new");
361 
362 	/* optionally accept client certs, but don't try to verify them */
363 	tls_config_verify_client_optional(tlsconf);
364 	tls_config_insecure_noverifycert(tlsconf);
365 
366 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
367 		fatal("tls_config_set_protocols");
368 
369 	if ((ctx = tls_server()) == NULL)
370 		fatal("tls_server failure");
371 
372 	/* we need to set something, then we can add how many key we want */
373 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
374 		fatal("tls_config_set_keypair_file failed");
375 
376 	for (h = &hosts[1]; h->domain != NULL; ++h) {
377 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
378 			fatal("failed to load the keypair (%s, %s)",
379 			    h->cert, h->key);
380 	}
381 
382 	if (tls_configure(ctx, tlsconf) == -1)
383 		fatal("tls_configure: %s", tls_error(ctx));
384 }
385 
386 static int
387 listener_main(void)
388 {
389 	load_default_mime(&conf.mime);
390 	load_vhosts();
391 	sandbox();
392 	loop(ctx, sock4, sock6);
393 	return 0;
394 }
395 
396 void
397 init_config(void)
398 {
399 	size_t i;
400 
401 	bzero(hosts, sizeof(hosts));
402 	for (i = 0; i < HOSTSLEN; ++i)
403 		hosts[i].dirfd = -1;
404 
405 	conf.port = 1965;
406 	conf.ipv6 = 0;
407 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
408 
409 	init_mime(&conf.mime);
410 
411 	conf.chroot = NULL;
412 	conf.user = NULL;
413 }
414 
415 void
416 drop_priv(void)
417 {
418 	struct passwd *pw = NULL;
419 
420 	if (conf.chroot != NULL && conf.user == NULL)
421 		fatal("can't chroot without an user to switch to after.");
422 
423 	if (conf.user != NULL) {
424 		if ((pw = getpwnam(conf.user)) == NULL)
425 			fatal("can't find user %s", conf.user);
426 	}
427 
428 	if (conf.chroot != NULL) {
429 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
430 			fatal("%s: %s", conf.chroot, strerror(errno));
431 	}
432 
433 	if (pw != NULL) {
434 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
435 			fatal("setresuid(%d): %s", pw->pw_uid,
436 			    strerror(errno));
437 	}
438 
439 	if (getuid() == 0)
440 		LOGW(NULL, "%s",
441 		    "not a good idea to run a network daemon as root");
442 }
443 
444 void
445 usage(const char *me)
446 {
447 	fprintf(stderr,
448 	    "USAGE: %s [-fn] [-c config] | [-6h] [-d certs-dir] [-H host]"
449 	    "       [-p port] [-x cgi] [dir]",
450 	    me);
451 }
452 
453 static int
454 serve(int argc, char **argv, int *p)
455 {
456 	char path[PATH_MAX];
457 
458 	if (config_path == NULL) {
459 		if (hostname == NULL)
460 			hostname = "localhost";
461 		if (certs_dir == NULL)
462 			certs_dir = data_dir();
463 		load_local_cert(hostname, certs_dir);
464 
465 		hosts[0].domain = "*";
466 		hosts[0].locations[0].auto_index = 1;
467 		hosts[0].locations[0].match = "*";
468 
469 		switch (argc) {
470 		case 0:
471 			hosts[0].dir = getcwd(path, sizeof(path));
472 			break;
473 		case 1:
474 			hosts[0].dir = absolutify_path(argv[0]);
475 			break;
476 		default:
477 			usage(getprogname());
478 			return 1;
479 		}
480 
481 		LOGN(NULL, "serving %s on port %d", hosts[0].dir, conf.port);
482 	}
483 
484 	/* setup tls before dropping privileges: we don't want user
485 	 * to put private certs inside the chroot. */
486 	setup_tls();
487 
488 	switch (fork()) {
489 	case -1:
490 		fatal("fork: %s", strerror(errno));
491 
492 	case 0:			/* child */
493 		close(p[0]);
494 		exfd = p[1];
495 		drop_priv();
496 		listener_main();
497 		_exit(0);
498 
499 	default:		/* parent */
500 		close(p[1]);
501 		exfd = p[0];
502 		drop_priv();
503 		return executor_main();
504 	}
505 }
506 
507 int
508 main(int argc, char **argv)
509 {
510 	int ch, p[2];
511 	int conftest = 0, configless = 0;
512 
513 	init_config();
514 
515 	while ((ch = getopt(argc, argv, "6c:d:fH:hnp:vx:")) != -1) {
516 		switch (ch) {
517 		case '6':
518 			conf.ipv6 = 1;
519 			configless = 1;
520 			break;
521 
522 		case 'c':
523 			config_path = optarg;
524 			break;
525 
526 		case 'd':
527 			certs_dir = optarg;
528 			configless = 1;
529 			break;
530 
531 		case 'f':
532 			foreground = 1;
533 			break;
534 
535 		case 'H':
536 			hostname = optarg;
537 			configless = 1;
538 			break;
539 
540 		case 'h':
541 			usage(*argv);
542 			return 0;
543 
544 		case 'n':
545 			conftest = 1;
546 			break;
547 
548 		case 'p':
549 			conf.port = parse_portno(optarg);
550 			configless = 1;
551 			break;
552 
553 		case 'v':
554 			verbose = 1;
555 			break;
556 
557 		case 'x':
558 			/* drop the starting / (if any) */
559 			if (*optarg == '/')
560 				optarg++;
561 			hosts[0].cgi = optarg;
562 			configless = 1;
563 			break;
564 
565 		default:
566 			usage(*argv);
567 			return 1;
568 		}
569 	}
570 	argc -= optind;
571 	argv += optind;
572 
573 	if (config_path == NULL) {
574 		configless = 1;
575 		foreground = 1;
576 	}
577 
578 	if (config_path != NULL && (argc > 0 || configless))
579 		err(1, "can't specify options in config mode.");
580 
581 	if (conftest) {
582 		parse_conf(config_path);
583 		puts("config OK");
584 		return 0;
585 	}
586 
587 	signal(SIGPIPE, SIG_IGN);
588 	signal(SIGCHLD, SIG_IGN);
589 
590 #ifdef SIGINFO
591 	signal(SIGINFO, sig_handler);
592 #endif
593 	signal(SIGUSR2, sig_handler);
594 	signal(SIGHUP, SIG_IGN);
595 
596 	if (!foreground && !configless) {
597 		if (daemon(1, 1) == -1)
598 			fatal("daemon: %s", strerror(errno));
599 	}
600 
601 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC,
602 	    PF_UNSPEC, p) == -1)
603 		fatal("socketpair: %s", strerror(errno));
604 
605 	if (config_path != NULL)
606 		parse_conf(config_path);
607 
608 	sock4 = make_socket(conf.port, AF_INET);
609 	sock6 = -1;
610 	if (conf.ipv6)
611 		sock6 = make_socket(conf.port, AF_INET6);
612 
613 	return serve(argc, argv, p);
614 }