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Date:: Wed Jan 27 15:00:55 2021 UTC
Message:: make configless mode works again. also accept every host
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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 <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 exfd, foreground, goterror;
36 
37 struct conf conf;
38 
39 struct tls *ctx;
40 
41 void
42 fatal(const char *fmt, ...)
43 {
44 	va_list ap;
45 
46 	va_start(ap, fmt);
47 
48 	if (foreground) {
49 		vfprintf(stderr, fmt, ap);
50 		fprintf(stderr, "\n");
51 	} else
52 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
53 
54 	va_end(ap);
55 	exit(1);
56 }
57 
58 void
59 logs(int priority, struct client *c,
60     const char *fmt, ...)
61 {
62 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
63 	char *fmted, *s;
64 	size_t len;
65 	int ec;
66 	va_list ap;
67 
68 	va_start(ap, fmt);
69 
70 	if (c == NULL) {
71 		strncpy(hbuf, "<internal>", sizeof(hbuf));
72 		sbuf[0] = '\0';
73 	} else {
74 		len = sizeof(c->addr);
75 		ec = getnameinfo((struct sockaddr*)&c->addr, len,
76 		    hbuf, sizeof(hbuf),
77 		    sbuf, sizeof(sbuf),
78 		    NI_NUMERICHOST | NI_NUMERICSERV);
79 		if (ec != 0)
80 			fatal("getnameinfo: %s", gai_strerror(ec));
81 	}
82 
83 	if (vasprintf(&fmted, fmt, ap) == -1)
84 		fatal("vasprintf: %s", strerror(errno));
85 
86 	if (foreground)
87 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
88 	else {
89 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
90 			fatal("asprintf: %s", strerror(errno));
91 		syslog(priority | LOG_DAEMON, "%s", s);
92 		free(s);
93 	}
94 
95 	free(fmted);
96 
97 	va_end(ap);
98 }
99 
100 /* strchr, but with a bound */
101 static char *
102 gmid_strnchr(char *s, int c, size_t len)
103 {
104 	size_t i;
105 
106 	for (i = 0; i < len; ++i)
107 		if (s[i] == c)
108 			return &s[i];
109 	return NULL;
110 }
111 
112 void
113 log_request(struct client *c, char *meta, size_t l)
114 {
115 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV], b[GEMINI_URL_LEN];
116 	char *t;
117 	size_t len;
118 	int ec;
119 
120 	len = sizeof(c->addr);
121 	ec = getnameinfo((struct sockaddr*)&c->addr, len,
122 	    hbuf, sizeof(hbuf),
123 	    sbuf, sizeof(sbuf),
124 	    NI_NUMERICHOST | NI_NUMERICSERV);
125 	if (ec != 0)
126 		fatal("getnameinfo: %s", gai_strerror(ec));
127 
128 	if (c->iri.schema != NULL) {
129 		/* serialize the IRI */
130 		strlcpy(b, c->iri.schema, sizeof(b));
131 		strlcat(b, "://", sizeof(b));
132 
133 		/* log the decoded host name, but if it was invalid
134 		 * use the raw one. */
135 		if (*c->domain != '\0')
136 			strlcat(b, c->domain, sizeof(b));
137 		else
138 			strlcat(b, c->iri.host, sizeof(b));
139 
140 		strlcat(b, "/", sizeof(b));
141 		strlcat(b, c->iri.path, sizeof(b)); /* TODO: sanitize UTF8 */
142 		if (*c->iri.query != '\0') {	    /* TODO: sanitize UTF8 */
143 			strlcat(b, "?", sizeof(b));
144 			strlcat(b, c->iri.query, sizeof(b));
145 		}
146 	} else {
147 		strlcpy(b, c->req, sizeof(b));
148 	}
149 
150 	if ((t = gmid_strnchr(meta, '\r', l)) == NULL)
151 		t = meta + len;
152 
153 	if (foreground)
154 		fprintf(stderr, "%s:%s GET %s %.*s\n", hbuf, sbuf, b,
155 		    (int)(t - meta), meta);
156 	else
157 		syslog(LOG_INFO | LOG_DAEMON, "%s:%s GET %s %.*s",
158 		    hbuf, sbuf, b, (int)(t - meta), meta);
159 }
160 
161 void
162 sig_handler(int sig)
163 {
164 	(void)sig;
165 }
166 
167 int
168 starts_with(const char *str, const char *prefix)
169 {
170 	size_t i;
171 
172 	if (prefix == NULL)
173 		return 0;
174 
175 	for (i = 0; prefix[i] != '\0'; ++i)
176 		if (str[i] != prefix[i])
177 			return 0;
178 	return 1;
179 }
180 
181 int
182 ends_with(const char *str, const char *sufx)
183 {
184 	size_t i, j;
185 
186 	i = strlen(str);
187 	j = strlen(sufx);
188 
189 	if (j > i)
190 		return 0;
191 
192 	i -= j;
193 	for (j = 0; str[i] != '\0'; i++, j++)
194 		if (str[i] != sufx[j])
195 			return 0;
196 	return 1;
197 }
198 
199 ssize_t
200 filesize(int fd)
201 {
202 	ssize_t len;
203 
204 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
205 		return -1;
206 	if (lseek(fd, 0, SEEK_SET) == -1)
207 		return -1;
208 	return len;
209 }
210 
211 char *
212 absolutify_path(const char *path)
213 {
214 	char *wd, *r;
215 
216 	if (*path == '/')
217 		return strdup(path);
218 
219 	wd = getcwd(NULL, 0);
220 	if (asprintf(&r, "%s/%s", wd, path) == -1)
221 		fatal("asprintf: %s", strerror(errno));
222 	free(wd);
223 	return r;
224 }
225 
226 void
227 gen_certificate(const char *host, const char *certpath, const char *keypath)
228 {
229 	BIGNUM		e;
230 	EVP_PKEY	*pkey;
231 	RSA		*rsa;
232 	X509		*x509;
233 	X509_NAME	*name;
234 	FILE		*f;
235 	const char	*org = "gmid";
236 
237 	LOGN(NULL, "generating a new certificate for %s in %s (it could take a while)",
238 	    host, certpath);
239 
240 	if ((pkey = EVP_PKEY_new()) == NULL)
241                 fatal("couldn't create a new private key");
242 
243 	if ((rsa = RSA_new()) == NULL)
244 		fatal("could'nt generate rsa");
245 
246 	BN_init(&e);
247 	BN_set_word(&e, 17);
248 	if (!RSA_generate_key_ex(rsa, 4096, &e, NULL))
249 		fatal("couldn't generate a rsa key");
250 
251 	if (!EVP_PKEY_assign_RSA(pkey, rsa))
252 		fatal("couldn't assign the key");
253 
254 	if ((x509 = X509_new()) == NULL)
255 		fatal("couldn't generate the X509 certificate");
256 
257 	ASN1_INTEGER_set(X509_get_serialNumber(x509), 1);
258 	X509_gmtime_adj(X509_get_notBefore(x509), 0);
259 	X509_gmtime_adj(X509_get_notAfter(x509), 315360000L); /* 10 years */
260 
261 	if (!X509_set_pubkey(x509, pkey))
262 		fatal("couldn't set the public key");
263 
264 	name = X509_get_subject_name(x509);
265 	if (!X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, org, -1, -1, 0))
266 		fatal("couldn't add N to cert");
267 	if (!X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, host, -1, -1, 0))
268 		fatal("couldn't add CN to cert");
269 	X509_set_issuer_name(x509, name);
270 
271 	if (!X509_sign(x509, pkey, EVP_sha256()))
272                 fatal("couldn't sign the certificate");
273 
274 	if ((f = fopen(keypath, "w")) == NULL)
275 		fatal("fopen(%s): %s", keypath, strerror(errno));
276 	if (!PEM_write_PrivateKey(f, pkey, NULL, NULL, 0, NULL, NULL))
277 		fatal("couldn't write private key");
278 	fclose(f);
279 
280 	if ((f = fopen(certpath, "w")) == NULL)
281 		fatal("fopen(%s): %s", certpath, strerror(errno));
282 	if (!PEM_write_X509(f, x509))
283 		fatal("couldn't write cert");
284 	fclose(f);
285 
286 	X509_free(x509);
287 	RSA_free(rsa);
288 }
289 
290 /* XXX: create recursively */
291 void
292 mkdirs(const char *path)
293 {
294 	if (mkdir(path, 0755) == -1 && errno != EEXIST)
295 		fatal("can't mkdir %s: %s", path, strerror(errno));
296 }
297 
298 /* $XDG_DATA_HOME/gmid */
299 char *
300 data_dir(void)
301 {
302 	const char *home, *xdg;
303 	char dir[PATH_MAX];
304 	char *t;
305 
306 	if ((xdg = getenv("XDG_DATA_HOME")) == NULL) {
307 		if ((home = getenv("HOME")) == NULL)
308 			errx(1, "XDG_DATA_HOME and HOME both empty");
309 		if (asprintf(&t, "%s/.local/share/gmid", home) == -1)
310 			err(1, "asprintf");
311 		mkdirs(t);
312 		return t;
313 	}
314 
315 	if (asprintf(&t, "%s/gmid", xdg) == -1)
316 		err(1, "asprintf");
317 	mkdirs(t);
318 	return t;
319 }
320 
321 void
322 load_local_cert(const char *hostname, const char *dir)
323 {
324 	char *cert, *key;
325 
326 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
327 		errx(1, "asprintf");
328 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
329 		errx(1, "asprintf");
330 
331 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
332 		gen_certificate(hostname, cert, key);
333 
334 	hosts[0].cert = cert;
335 	hosts[0].key = key;
336 	hosts[0].domain = hostname;
337 }
338 
339 void
340 yyerror(const char *msg)
341 {
342 	goterror = 1;
343 	fprintf(stderr, "%d: %s\n", yylineno, msg);
344 }
345 
346 int
347 parse_portno(const char *p)
348 {
349 	const char *errstr;
350 	int n;
351 
352 	n = strtonum(p, 0, UINT16_MAX, &errstr);
353 	if (errstr != NULL)
354 		errx(1, "port number is %s: %s", errstr, p);
355 	return n;
356 }
357 
358 void
359 parse_conf(const char *path)
360 {
361 	if ((yyin = fopen(path, "r")) == NULL)
362 		fatal("cannot open config %s", path);
363 	yyparse();
364 	fclose(yyin);
365 
366 	if (goterror)
367 		exit(1);
368 }
369 
370 void
371 load_vhosts(void)
372 {
373 	struct vhost *h;
374 
375 	for (h = hosts; h->domain != NULL; ++h) {
376 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
377 			fatal("open %s for domain %s", h->dir, h->domain);
378 	}
379 }
380 
381 int
382 make_socket(int port, int family)
383 {
384 	int sock, v;
385 	struct sockaddr_in addr4;
386 	struct sockaddr_in6 addr6;
387 	struct sockaddr *addr;
388 	socklen_t len;
389 
390         switch (family) {
391 	case AF_INET:
392 		bzero(&addr4, sizeof(addr4));
393 		addr4.sin_family = family;
394 		addr4.sin_port = htons(port);
395 		addr4.sin_addr.s_addr = INADDR_ANY;
396 		addr = (struct sockaddr*)&addr4;
397 		len = sizeof(addr4);
398 		break;
399 
400 	case AF_INET6:
401 		bzero(&addr6, sizeof(addr6));
402 		addr6.sin6_family = AF_INET6;
403 		addr6.sin6_port = htons(port);
404 		addr6.sin6_addr = in6addr_any;
405 		addr = (struct sockaddr*)&addr6;
406 		len = sizeof(addr6);
407 		break;
408 
409 	default:
410 		/* unreachable */
411 		abort();
412 	}
413 
414 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
415 		fatal("socket: %s", strerror(errno));
416 
417 	v = 1;
418 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
419 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
420 
421 	v = 1;
422 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
423 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
424 
425 	mark_nonblock(sock);
426 
427 	if (bind(sock, addr, len) == -1)
428 		fatal("bind: %s", strerror(errno));
429 
430 	if (listen(sock, 16) == -1)
431 		fatal("listen: %s", strerror(errno));
432 
433 	return sock;
434 }
435 
436 void
437 setup_tls(void)
438 {
439 	struct tls_config *tlsconf;
440 	struct vhost *h;
441 
442 	if ((tlsconf = tls_config_new()) == NULL)
443 		fatal("tls_config_new");
444 
445 	/* optionally accept client certs, but don't try to verify them */
446 	tls_config_verify_client_optional(tlsconf);
447 	tls_config_insecure_noverifycert(tlsconf);
448 
449 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
450 		fatal("tls_config_set_protocols");
451 
452 	if ((ctx = tls_server()) == NULL)
453 		fatal("tls_server failure");
454 
455 	/* we need to set something, then we can add how many key we want */
456 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
457 		fatal("tls_config_set_keypair_file failed");
458 
459 	for (h = &hosts[1]; h->domain != NULL; ++h) {
460 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
461 			fatal("failed to load the keypair (%s, %s)",
462 			    h->cert, h->key);
463 	}
464 
465 	if (tls_configure(ctx, tlsconf) == -1)
466 		fatal("tls_configure: %s", tls_error(ctx));
467 }
468 
469 int
470 listener_main(void)
471 {
472 	int sock4, sock6;
473 
474 	load_default_mime(&conf.mime);
475 
476 	sock4 = make_socket(conf.port, AF_INET);
477 	sock6 = -1;
478 	if (conf.ipv6)
479 		sock6 = make_socket(conf.port, AF_INET6);
480 
481 	load_vhosts();
482 
483 	sandbox();
484 	loop(ctx, sock4, sock6);
485 
486 	return 0;
487 }
488 
489 void
490 init_config(void)
491 {
492 	size_t i;
493 
494 	bzero(hosts, sizeof(hosts));
495 	for (i = 0; i < HOSTSLEN; ++i)
496 		hosts[i].dirfd = -1;
497 
498 	conf.port = 1965;
499 	conf.ipv6 = 0;
500 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
501 
502 	init_mime(&conf.mime);
503 
504 	conf.chroot = NULL;
505 	conf.user = NULL;
506 }
507 
508 void
509 drop_priv(void)
510 {
511 	struct passwd *pw = NULL;
512 
513 	if (conf.chroot != NULL && conf.user == NULL)
514 		fatal("can't chroot without an user to switch to after.");
515 
516 	if (conf.user != NULL) {
517 		if ((pw = getpwnam(conf.user)) == NULL)
518 			fatal("can't find user %s", conf.user);
519 	}
520 
521 	if (conf.chroot != NULL) {
522 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
523 			fatal("%s: %s", conf.chroot, strerror(errno));
524 	}
525 
526 	if (pw != NULL) {
527 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
528 			fatal("setresuid(%d): %s", pw->pw_uid,
529 			    strerror(errno));
530 	}
531 
532 	if (getuid() == 0)
533 		LOGW(NULL, "%s",
534 		    "not a good idea to run a network daemon as root");
535 }
536 
537 void
538 usage(const char *me)
539 {
540 	fprintf(stderr,
541 	    "USAGE: %s [-fn] [-c config] | [-6h] [-d certs-dir] [-H host]"
542 	    "       [-p port] [-x cgi] [dir]",
543 	    me);
544 }
545 
546 int
547 main(int argc, char **argv)
548 {
549 	int ch, p[2];
550 	const char *config_path = NULL, *certs_dir = NULL, *hostname = NULL;
551 	int conftest = 0, configless = 0;
552 
553 	init_config();
554 
555 	while ((ch = getopt(argc, argv, "6c:d:fH:hnp:x:")) != -1) {
556 		switch (ch) {
557 		case '6':
558 			conf.ipv6 = 1;
559 			configless = 1;
560 			break;
561 
562 		case 'c':
563 			config_path = optarg;
564 			break;
565 
566 		case 'd':
567 			certs_dir = optarg;
568 			configless = 1;
569 			break;
570 
571 		case 'f':
572 			foreground = 1;
573 			break;
574 
575 		case 'H':
576 			hostname = optarg;
577 			configless = 1;
578 			break;
579 
580 		case 'h':
581 			usage(*argv);
582 			return 0;
583 
584 		case 'n':
585 			conftest = 1;
586 			break;
587 
588 		case 'p':
589 			conf.port = parse_portno(optarg);
590 			configless = 1;
591 			break;
592 
593 		case 'x':
594 			/* drop the starting / (if any) */
595 			if (*optarg == '/')
596 				optarg++;
597 			hosts[0].cgi = optarg;
598 			configless = 1;
599 			break;
600 
601 		default:
602 			usage(*argv);
603 			return 1;
604 		}
605 	}
606 	argc -= optind;
607 	argv += optind;
608 
609 	if (config_path != NULL) {
610 		if (argc > 0 || configless)
611 			fatal("can't specify options is config mode.");
612 
613 		parse_conf(config_path);
614 	} else {
615 		configless = 1;
616 		foreground = 1;
617 
618 		if (hostname == NULL)
619 			hostname = "localhost";
620 		if (certs_dir == NULL)
621 			certs_dir = data_dir();
622 		load_local_cert(hostname, certs_dir);
623 
624 		hosts[0].domain = "*";
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 	signal(SIGHUP, SIG_IGN);
661 
662 	if (!foreground && !configless) {
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 }