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Date:: Wed Jan 27 10:47:49 2021 UTC
Message:: initial punycode support
Actions:: History | Blame | Raw File
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 <netdb.h>
23 #include <pwd.h>
24 #include <signal.h>
25 #include <stdarg.h>
26 #include <string.h>
27 
28 #include <openssl/pem.h>
29 #include <openssl/x509.h>
30 
31 #include "gmid.h"
32 
33 struct vhost hosts[HOSTSLEN];
34 
35 int goterror;
36 
37 int exfd;
38 
39 struct conf conf;
40 
41 struct tls *ctx;
42 
43 void
44 fatal(const char *fmt, ...)
45 {
46 	va_list ap;
47 
48 	va_start(ap, fmt);
49 
50 	if (conf.foreground) {
51 		vfprintf(stderr, fmt, ap);
52 		fprintf(stderr, "\n");
53 	} else
54 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
55 
56 	va_end(ap);
57 	exit(1);
58 }
59 
60 void
61 logs(int priority, struct client *c,
62     const char *fmt, ...)
63 {
64 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
65 	char *fmted, *s;
66 	size_t len;
67 	int ec;
68 	va_list ap;
69 
70 	va_start(ap, fmt);
71 
72 	if (c == NULL) {
73 		strncpy(hbuf, "<internal>", sizeof(hbuf));
74 		sbuf[0] = '\0';
75 	} else {
76 		len = sizeof(c->addr);
77 		ec = getnameinfo((struct sockaddr*)&c->addr, len,
78 		    hbuf, sizeof(hbuf),
79 		    sbuf, sizeof(sbuf),
80 		    NI_NUMERICHOST | NI_NUMERICSERV);
81 		if (ec != 0)
82 			fatal("getnameinfo: %s", gai_strerror(ec));
83 	}
84 
85 	if (vasprintf(&fmted, fmt, ap) == -1)
86 		fatal("vasprintf: %s", strerror(errno));
87 
88 	if (conf.foreground)
89 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
90 	else {
91 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
92 			fatal("asprintf: %s", strerror(errno));
93 		syslog(priority | LOG_DAEMON, "%s", s);
94 		free(s);
95 	}
96 
97 	free(fmted);
98 
99 	va_end(ap);
100 }
101 
102 /* strchr, but with a bound */
103 static char *
104 gmid_strnchr(char *s, int c, size_t len)
105 {
106 	size_t i;
107 
108 	for (i = 0; i < len; ++i)
109 		if (s[i] == c)
110 			return &s[i];
111 	return NULL;
112 }
113 
114 void
115 log_request(struct client *c, char *meta, size_t l)
116 {
117 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV], b[GEMINI_URL_LEN];
118 	char *t;
119 	size_t len;
120 	int ec;
121 
122 	len = sizeof(c->addr);
123 	ec = getnameinfo((struct sockaddr*)&c->addr, len,
124 	    hbuf, sizeof(hbuf),
125 	    sbuf, sizeof(sbuf),
126 	    NI_NUMERICHOST | NI_NUMERICSERV);
127 	if (ec != 0)
128 		fatal("getnameinfo: %s", gai_strerror(ec));
129 
130 	if (c->iri.schema != NULL) {
131 		/* serialize the IRI */
132 		strlcpy(b, c->iri.schema, sizeof(b));
133 		strlcat(b, "://", sizeof(b));
134 
135 		/* log the decoded host name, but if it was invalid
136 		 * use the raw one. */
137 		if (*c->domain != '\0')
138 			strlcat(b, c->domain, sizeof(b));
139 		else
140 			strlcat(b, c->iri.host, sizeof(b));
141 
142 		strlcat(b, "/", sizeof(b));
143 		strlcat(b, c->iri.path, sizeof(b)); /* TODO: sanitize UTF8 */
144 		if (*c->iri.query != '\0') {	    /* TODO: sanitize UTF8 */
145 			strlcat(b, "?", sizeof(b));
146 			strlcat(b, c->iri.query, sizeof(b));
147 		}
148 	} else {
149 		strlcpy(b, c->req, sizeof(b));
150 	}
151 
152 	if ((t = gmid_strnchr(meta, '\r', l)) == NULL)
153 		t = meta + len;
154 
155 	if (conf.foreground)
156 		fprintf(stderr, "%s:%s GET %s %.*s\n", hbuf, sbuf, b,
157 		    (int)(t - meta), meta);
158 	else
159 		syslog(LOG_INFO | LOG_DAEMON, "%s:%s GET %s %.*s",
160 		    hbuf, sbuf, b, (int)(t - meta), meta);
161 }
162 
163 void
164 sig_handler(int sig)
165 {
166 	(void)sig;
167 }
168 
169 int
170 starts_with(const char *str, const char *prefix)
171 {
172 	size_t i;
173 
174 	if (prefix == NULL)
175 		return 0;
176 
177 	for (i = 0; prefix[i] != '\0'; ++i)
178 		if (str[i] != prefix[i])
179 			return 0;
180 	return 1;
181 }
182 
183 int
184 ends_with(const char *str, const char *sufx)
185 {
186 	size_t i, j;
187 
188 	i = strlen(str);
189 	j = strlen(sufx);
190 
191 	if (j > i)
192 		return 0;
193 
194 	i -= j;
195 	for (j = 0; str[i] != '\0'; i++, j++)
196 		if (str[i] != sufx[j])
197 			return 0;
198 	return 1;
199 }
200 
201 ssize_t
202 filesize(int fd)
203 {
204 	ssize_t len;
205 
206 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
207 		return -1;
208 	if (lseek(fd, 0, SEEK_SET) == -1)
209 		return -1;
210 	return len;
211 }
212 
213 char *
214 absolutify_path(const char *path)
215 {
216 	char *wd, *r;
217 
218 	if (*path == '/')
219 		return strdup(path);
220 
221 	wd = getcwd(NULL, 0);
222 	if (asprintf(&r, "%s/%s", wd, path) == -1)
223 		fatal("asprintf: %s", strerror(errno));
224 	free(wd);
225 	return r;
226 }
227 
228 void
229 gen_certificate(const char *host, const char *certpath, const char *keypath)
230 {
231 	BIGNUM		e;
232 	EVP_PKEY	*pkey;
233 	RSA		*rsa;
234 	X509		*x509;
235 	X509_NAME	*name;
236 	FILE		*f;
237 	const char	*org = "gmid";
238 
239 	LOGN(NULL, "generating a new certificate for %s in %s (it could take a while)",
240 	    host, certpath);
241 
242 	if ((pkey = EVP_PKEY_new()) == NULL)
243                 fatal("couldn't create a new private key");
244 
245 	if ((rsa = RSA_new()) == NULL)
246 		fatal("could'nt generate rsa");
247 
248 	BN_init(&e);
249 	BN_set_word(&e, 17);
250 	if (!RSA_generate_key_ex(rsa, 4096, &e, NULL))
251 		fatal("couldn't generate a rsa key");
252 
253 	if (!EVP_PKEY_assign_RSA(pkey, rsa))
254 		fatal("couldn't assign the key");
255 
256 	if ((x509 = X509_new()) == NULL)
257 		fatal("couldn't generate the X509 certificate");
258 
259 	ASN1_INTEGER_set(X509_get_serialNumber(x509), 1);
260 	X509_gmtime_adj(X509_get_notBefore(x509), 0);
261 	X509_gmtime_adj(X509_get_notAfter(x509), 315360000L); /* 10 years */
262 
263 	if (!X509_set_pubkey(x509, pkey))
264 		fatal("couldn't set the public key");
265 
266 	name = X509_get_subject_name(x509);
267 	if (!X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, org, -1, -1, 0))
268 		fatal("couldn't add N to cert");
269 	if (!X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, host, -1, -1, 0))
270 		fatal("couldn't add CN to cert");
271 	X509_set_issuer_name(x509, name);
272 
273 	if (!X509_sign(x509, pkey, EVP_sha256()))
274                 fatal("couldn't sign the certificate");
275 
276 	if ((f = fopen(keypath, "w")) == NULL)
277 		fatal("fopen(%s): %s", keypath, strerror(errno));
278 	if (!PEM_write_PrivateKey(f, pkey, NULL, NULL, 0, NULL, NULL))
279 		fatal("couldn't write private key");
280 	fclose(f);
281 
282 	if ((f = fopen(certpath, "w")) == NULL)
283 		fatal("fopen(%s): %s", certpath, strerror(errno));
284 	if (!PEM_write_X509(f, x509))
285 		fatal("couldn't write cert");
286 	fclose(f);
287 
288 	X509_free(x509);
289 	RSA_free(rsa);
290 }
291 
292 /* XXX: create recursively */
293 void
294 mkdirs(const char *path)
295 {
296 	if (mkdir(path, 0755) == -1 && errno != EEXIST)
297 		fatal("can't mkdir %s: %s", path, strerror(errno));
298 }
299 
300 /* $XDG_DATA_HOME/gmid */
301 char *
302 data_dir(void)
303 {
304 	const char *home, *xdg;
305 	char dir[PATH_MAX];
306 	char *t;
307 
308 	if ((xdg = getenv("XDG_DATA_HOME")) == NULL) {
309 		if ((home = getenv("HOME")) == NULL)
310 			errx(1, "XDG_DATA_HOME and HOME both empty");
311 		if (asprintf(&t, "%s/.local/share/gmid", home) == -1)
312 			err(1, "asprintf");
313 		mkdirs(t);
314 		return t;
315 	}
316 
317 	if (asprintf(&t, "%s/gmid", xdg) == -1)
318 		err(1, "asprintf");
319 	mkdirs(t);
320 	return t;
321 }
322 
323 void
324 load_local_cert(const char *hostname, const char *dir)
325 {
326 	char *cert, *key;
327 
328 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
329 		errx(1, "asprintf");
330 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
331 		errx(1, "asprintf");
332 
333 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
334 		gen_certificate(hostname, cert, key);
335 
336 	hosts[0].cert = cert;
337 	hosts[0].key = key;
338 	hosts[0].domain = hostname;
339 }
340 
341 void
342 yyerror(const char *msg)
343 {
344 	goterror = 1;
345 	fprintf(stderr, "%d: %s\n", yylineno, msg);
346 }
347 
348 int
349 parse_portno(const char *p)
350 {
351 	const char *errstr;
352 	int n;
353 
354 	n = strtonum(p, 0, UINT16_MAX, &errstr);
355 	if (errstr != NULL)
356 		errx(1, "port number is %s: %s", errstr, p);
357 	return n;
358 }
359 
360 void
361 parse_conf(const char *path)
362 {
363 	if ((yyin = fopen(path, "r")) == NULL)
364 		fatal("cannot open config %s", path);
365 	yyparse();
366 	fclose(yyin);
367 
368 	if (goterror)
369 		exit(1);
370 }
371 
372 void
373 load_vhosts(void)
374 {
375 	struct vhost *h;
376 
377 	for (h = hosts; h->domain != NULL; ++h) {
378 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
379 			fatal("open %s for domain %s", h->dir, h->domain);
380 	}
381 }
382 
383 int
384 make_socket(int port, int family)
385 {
386 	int sock, v;
387 	struct sockaddr_in addr4;
388 	struct sockaddr_in6 addr6;
389 	struct sockaddr *addr;
390 	socklen_t len;
391 
392         switch (family) {
393 	case AF_INET:
394 		bzero(&addr4, sizeof(addr4));
395 		addr4.sin_family = family;
396 		addr4.sin_port = htons(port);
397 		addr4.sin_addr.s_addr = INADDR_ANY;
398 		addr = (struct sockaddr*)&addr4;
399 		len = sizeof(addr4);
400 		break;
401 
402 	case AF_INET6:
403 		bzero(&addr6, sizeof(addr6));
404 		addr6.sin6_family = AF_INET6;
405 		addr6.sin6_port = htons(port);
406 		addr6.sin6_addr = in6addr_any;
407 		addr = (struct sockaddr*)&addr6;
408 		len = sizeof(addr6);
409 		break;
410 
411 	default:
412 		/* unreachable */
413 		abort();
414 	}
415 
416 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
417 		fatal("socket: %s", strerror(errno));
418 
419 	v = 1;
420 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
421 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
422 
423 	v = 1;
424 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
425 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
426 
427 	mark_nonblock(sock);
428 
429 	if (bind(sock, addr, len) == -1)
430 		fatal("bind: %s", strerror(errno));
431 
432 	if (listen(sock, 16) == -1)
433 		fatal("listen: %s", strerror(errno));
434 
435 	return sock;
436 }
437 
438 void
439 setup_tls(void)
440 {
441 	struct tls_config *tlsconf;
442 	struct vhost *h;
443 
444 	if ((tlsconf = tls_config_new()) == NULL)
445 		fatal("tls_config_new");
446 
447 	/* optionally accept client certs, but don't try to verify them */
448 	tls_config_verify_client_optional(tlsconf);
449 	tls_config_insecure_noverifycert(tlsconf);
450 
451 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
452 		fatal("tls_config_set_protocols");
453 
454 	if ((ctx = tls_server()) == NULL)
455 		fatal("tls_server failure");
456 
457 	/* we need to set something, then we can add how many key we want */
458 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
459 		fatal("tls_config_set_keypair_file failed");
460 
461 	for (h = &hosts[1]; h->domain != NULL; ++h) {
462 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
463 			fatal("failed to load the keypair (%s, %s)",
464 			    h->cert, h->key);
465 	}
466 
467 	if (tls_configure(ctx, tlsconf) == -1)
468 		fatal("tls_configure: %s", tls_error(ctx));
469 }
470 
471 int
472 listener_main(void)
473 {
474 	int sock4, sock6;
475 
476 	load_default_mime(&conf.mime);
477 
478 	if (!conf.foreground && daemon(0, 1) == -1)
479 		exit(1);
480 
481 	sock4 = make_socket(conf.port, AF_INET);
482 	sock6 = -1;
483 	if (conf.ipv6)
484 		sock6 = make_socket(conf.port, AF_INET6);
485 
486 	load_vhosts();
487 
488 	sandbox();
489 	loop(ctx, sock4, sock6);
490 
491 	return 0;
492 }
493 
494 void
495 init_config(void)
496 {
497 	size_t i;
498 
499 	bzero(hosts, sizeof(hosts));
500 	for (i = 0; i < HOSTSLEN; ++i)
501 		hosts[i].dirfd = -1;
502 
503 	conf.foreground = 0;
504 	conf.port = 1965;
505 	conf.ipv6 = 0;
506 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
507 
508 	init_mime(&conf.mime);
509 
510 	conf.chroot = NULL;
511 	conf.user = NULL;
512 }
513 
514 void
515 drop_priv(void)
516 {
517 	struct passwd *pw = NULL;
518 
519 	if (conf.chroot != NULL && conf.user == NULL)
520 		fatal("can't chroot without an user to switch to after.");
521 
522 	if (conf.user != NULL) {
523 		if ((pw = getpwnam(conf.user)) == NULL)
524 			fatal("can't find user %s", conf.user);
525 	}
526 
527 	if (conf.chroot != NULL) {
528 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
529 			fatal("%s: %s", conf.chroot, strerror(errno));
530 	}
531 
532 	if (pw != NULL) {
533 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
534 			fatal("setresuid(%d): %s", pw->pw_uid,
535 			    strerror(errno));
536 	}
537 
538 	if (getuid() == 0)
539 		LOGW(NULL, "%s",
540 		    "not a good idea to run a network daemon as root");
541 }
542 
543 void
544 usage(const char *me)
545 {
546 	fprintf(stderr,
547 	    "USAGE: %s [-n] [-c config] | [-6h] [-d certs-dir] [-H host]"
548 	    "       [-p port] [-x cgi] [dir]",
549 	    me);
550 }
551 
552 int
553 main(int argc, char **argv)
554 {
555 	int ch, p[2];
556 	const char *config_path = NULL, *certs_dir = NULL, *hostname = NULL;
557 	int conftest = 0, configless = 0;
558 
559 	init_config();
560 
561 	while ((ch = getopt(argc, argv, "6c:d:H:hnp:x:")) != -1) {
562 		switch (ch) {
563 		case '6':
564 			conf.ipv6 = 1;
565 			configless = 1;
566 			break;
567 
568 		case 'c':
569 			config_path = optarg;
570 			break;
571 
572 		case 'd':
573 			certs_dir = optarg;
574 			configless = 1;
575 			break;
576 
577 		case 'H':
578 			hostname = optarg;
579 			configless = 1;
580 			break;
581 
582 		case 'h':
583 			usage(*argv);
584 			return 0;
585 
586 		case 'n':
587 			conftest = 1;
588 			break;
589 
590 		case 'p':
591 			conf.port = parse_portno(optarg);
592 			configless = 1;
593 			break;
594 
595 		case 'x':
596 			/* drop the starting / (if any) */
597 			if (*optarg == '/')
598 				optarg++;
599 			hosts[0].cgi = optarg;
600 			configless = 1;
601 			break;
602 
603 		default:
604 			usage(*argv);
605 			return 1;
606 		}
607 	}
608 	argc -= optind;
609 	argv += optind;
610 
611 	if (config_path != NULL) {
612 		if (argc > 0 || configless)
613 			fatal("can't specify options is config mode.");
614 
615 		parse_conf(config_path);
616 	} else {
617 		conf.foreground = 1;
618 
619 		if (hostname == NULL)
620 			hostname = "localhost";
621 		if (certs_dir == NULL)
622 			certs_dir = data_dir();
623 		load_local_cert(hostname, certs_dir);
624 
625 		hosts[0].locations[0].auto_index = 1;
626 		hosts[0].locations[0].match = "*";
627 
628                 switch (argc) {
629 		case 0:
630 			hosts[0].dir = ".";
631 			break;
632 		case 1:
633 			hosts[0].dir = argv[0];
634 			break;
635 		default:
636 			usage(getprogname());
637 			return 1;
638 		}
639 
640 		LOGN(NULL, "serving %s on port %d", hosts[0].dir, conf.port);
641 	}
642 
643 	if (conftest) {
644 		puts("config OK");
645 		return 0;
646 	}
647 
648 	/* setup tls before dropping privileges: we don't want user
649 	 * to put private certs inside the chroot. */
650 	setup_tls();
651 	drop_priv();
652 
653 	signal(SIGPIPE, SIG_IGN);
654 	signal(SIGCHLD, SIG_IGN);
655 
656 #ifdef SIGINFO
657 	signal(SIGINFO, sig_handler);
658 #endif
659 	signal(SIGUSR2, sig_handler);
660 
661 	if (!conf.foreground) {
662 		signal(SIGHUP, SIG_IGN);
663 		if (daemon(1, 1) == -1)
664 			fatal("daemon: %s", strerror(errno));
665 	}
666 
667 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
668 		fatal("socketpair: %s", strerror(errno));
669 
670 	switch (fork()) {
671 	case -1:
672 		fatal("fork: %s", strerror(errno));
673 
674 	case 0:			/* child */
675 		close(p[0]);
676 		exfd = p[1];
677 		listener_main();
678 		_exit(0);
679 
680 	default:		/* parent */
681 		close(p[1]);
682 		return executor_main(p[0]);
683 	}
684 }