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Date:: Wed Jan 27 15:35:55 2021 UTC
Message:: drop unused variable
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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 char *
168 absolutify_path(const char *path)
169 {
170 	char *wd, *r;
171 
172 	if (*path == '/')
173 		return strdup(path);
174 
175 	wd = getcwd(NULL, 0);
176 	if (asprintf(&r, "%s/%s", wd, path) == -1)
177 		fatal("asprintf: %s", strerror(errno));
178 	free(wd);
179 	return r;
180 }
181 
182 void
183 gen_certificate(const char *host, const char *certpath, const char *keypath)
184 {
185 	BIGNUM		e;
186 	EVP_PKEY	*pkey;
187 	RSA		*rsa;
188 	X509		*x509;
189 	X509_NAME	*name;
190 	FILE		*f;
191 	const char	*org = "gmid";
192 
193 	LOGN(NULL, "generating new certificate for %s (it could take a while)",
194 	    host);
195 
196 	if ((pkey = EVP_PKEY_new()) == NULL)
197                 fatal("couldn't create a new private key");
198 
199 	if ((rsa = RSA_new()) == NULL)
200 		fatal("could'nt generate rsa");
201 
202 	BN_init(&e);
203 	BN_set_word(&e, 17);
204 	if (!RSA_generate_key_ex(rsa, 4096, &e, NULL))
205 		fatal("couldn't generate a rsa key");
206 
207 	if (!EVP_PKEY_assign_RSA(pkey, rsa))
208 		fatal("couldn't assign the key");
209 
210 	if ((x509 = X509_new()) == NULL)
211 		fatal("couldn't generate the X509 certificate");
212 
213 	ASN1_INTEGER_set(X509_get_serialNumber(x509), 1);
214 	X509_gmtime_adj(X509_get_notBefore(x509), 0);
215 	X509_gmtime_adj(X509_get_notAfter(x509), 315360000L); /* 10 years */
216 
217 	if (!X509_set_pubkey(x509, pkey))
218 		fatal("couldn't set the public key");
219 
220 	name = X509_get_subject_name(x509);
221 	if (!X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, org, -1, -1, 0))
222 		fatal("couldn't add N to cert");
223 	if (!X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, host, -1, -1, 0))
224 		fatal("couldn't add CN to cert");
225 	X509_set_issuer_name(x509, name);
226 
227 	if (!X509_sign(x509, pkey, EVP_sha256()))
228                 fatal("couldn't sign the certificate");
229 
230 	if ((f = fopen(keypath, "w")) == NULL)
231 		fatal("fopen(%s): %s", keypath, strerror(errno));
232 	if (!PEM_write_PrivateKey(f, pkey, NULL, NULL, 0, NULL, NULL))
233 		fatal("couldn't write private key");
234 	fclose(f);
235 
236 	if ((f = fopen(certpath, "w")) == NULL)
237 		fatal("fopen(%s): %s", certpath, strerror(errno));
238 	if (!PEM_write_X509(f, x509))
239 		fatal("couldn't write cert");
240 	fclose(f);
241 
242 	X509_free(x509);
243 	RSA_free(rsa);
244 }
245 
246 /* XXX: create recursively */
247 void
248 mkdirs(const char *path)
249 {
250 	if (mkdir(path, 0755) == -1 && errno != EEXIST)
251 		fatal("can't mkdir %s: %s", path, strerror(errno));
252 }
253 
254 /* $XDG_DATA_HOME/gmid */
255 char *
256 data_dir(void)
257 {
258 	const char *home, *xdg;
259 	char *t;
260 
261 	if ((xdg = getenv("XDG_DATA_HOME")) == NULL) {
262 		if ((home = getenv("HOME")) == NULL)
263 			errx(1, "XDG_DATA_HOME and HOME both empty");
264 		if (asprintf(&t, "%s/.local/share/gmid", home) == -1)
265 			err(1, "asprintf");
266 		mkdirs(t);
267 		return t;
268 	}
269 
270 	if (asprintf(&t, "%s/gmid", xdg) == -1)
271 		err(1, "asprintf");
272 	mkdirs(t);
273 	return t;
274 }
275 
276 void
277 load_local_cert(const char *hostname, const char *dir)
278 {
279 	char *cert, *key;
280 
281 	if (asprintf(&cert, "%s/%s.cert.pem", dir, hostname) == -1)
282 		errx(1, "asprintf");
283 	if (asprintf(&key, "%s/%s.key.pem", dir, hostname) == -1)
284 		errx(1, "asprintf");
285 
286 	if (access(cert, R_OK) == -1 || access(key, R_OK) == -1)
287 		gen_certificate(hostname, cert, key);
288 
289 	hosts[0].cert = cert;
290 	hosts[0].key = key;
291 	hosts[0].domain = hostname;
292 }
293 
294 void
295 yyerror(const char *msg)
296 {
297 	goterror = 1;
298 	fprintf(stderr, "%d: %s\n", yylineno, msg);
299 }
300 
301 int
302 parse_portno(const char *p)
303 {
304 	const char *errstr;
305 	int n;
306 
307 	n = strtonum(p, 0, UINT16_MAX, &errstr);
308 	if (errstr != NULL)
309 		errx(1, "port number is %s: %s", errstr, p);
310 	return n;
311 }
312 
313 void
314 parse_conf(const char *path)
315 {
316 	if ((yyin = fopen(path, "r")) == NULL)
317 		fatal("cannot open config %s", path);
318 	yyparse();
319 	fclose(yyin);
320 
321 	if (goterror)
322 		exit(1);
323 }
324 
325 void
326 load_vhosts(void)
327 {
328 	struct vhost *h;
329 
330 	for (h = hosts; h->domain != NULL; ++h) {
331 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
332 			fatal("open %s for domain %s", h->dir, h->domain);
333 	}
334 }
335 
336 int
337 make_socket(int port, int family)
338 {
339 	int sock, v;
340 	struct sockaddr_in addr4;
341 	struct sockaddr_in6 addr6;
342 	struct sockaddr *addr;
343 	socklen_t len;
344 
345         switch (family) {
346 	case AF_INET:
347 		bzero(&addr4, sizeof(addr4));
348 		addr4.sin_family = family;
349 		addr4.sin_port = htons(port);
350 		addr4.sin_addr.s_addr = INADDR_ANY;
351 		addr = (struct sockaddr*)&addr4;
352 		len = sizeof(addr4);
353 		break;
354 
355 	case AF_INET6:
356 		bzero(&addr6, sizeof(addr6));
357 		addr6.sin6_family = AF_INET6;
358 		addr6.sin6_port = htons(port);
359 		addr6.sin6_addr = in6addr_any;
360 		addr = (struct sockaddr*)&addr6;
361 		len = sizeof(addr6);
362 		break;
363 
364 	default:
365 		/* unreachable */
366 		abort();
367 	}
368 
369 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
370 		fatal("socket: %s", strerror(errno));
371 
372 	v = 1;
373 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
374 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
375 
376 	v = 1;
377 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
378 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
379 
380 	mark_nonblock(sock);
381 
382 	if (bind(sock, addr, len) == -1)
383 		fatal("bind: %s", strerror(errno));
384 
385 	if (listen(sock, 16) == -1)
386 		fatal("listen: %s", strerror(errno));
387 
388 	return sock;
389 }
390 
391 void
392 setup_tls(void)
393 {
394 	struct tls_config *tlsconf;
395 	struct vhost *h;
396 
397 	if ((tlsconf = tls_config_new()) == NULL)
398 		fatal("tls_config_new");
399 
400 	/* optionally accept client certs, but don't try to verify them */
401 	tls_config_verify_client_optional(tlsconf);
402 	tls_config_insecure_noverifycert(tlsconf);
403 
404 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
405 		fatal("tls_config_set_protocols");
406 
407 	if ((ctx = tls_server()) == NULL)
408 		fatal("tls_server failure");
409 
410 	/* we need to set something, then we can add how many key we want */
411 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
412 		fatal("tls_config_set_keypair_file failed");
413 
414 	for (h = &hosts[1]; h->domain != NULL; ++h) {
415 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
416 			fatal("failed to load the keypair (%s, %s)",
417 			    h->cert, h->key);
418 	}
419 
420 	if (tls_configure(ctx, tlsconf) == -1)
421 		fatal("tls_configure: %s", tls_error(ctx));
422 }
423 
424 int
425 listener_main(void)
426 {
427 	int sock4, sock6;
428 
429 	load_default_mime(&conf.mime);
430 
431 	sock4 = make_socket(conf.port, AF_INET);
432 	sock6 = -1;
433 	if (conf.ipv6)
434 		sock6 = make_socket(conf.port, AF_INET6);
435 
436 	load_vhosts();
437 
438 	sandbox();
439 	loop(ctx, sock4, sock6);
440 
441 	return 0;
442 }
443 
444 void
445 init_config(void)
446 {
447 	size_t i;
448 
449 	bzero(hosts, sizeof(hosts));
450 	for (i = 0; i < HOSTSLEN; ++i)
451 		hosts[i].dirfd = -1;
452 
453 	conf.port = 1965;
454 	conf.ipv6 = 0;
455 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
456 
457 	init_mime(&conf.mime);
458 
459 	conf.chroot = NULL;
460 	conf.user = NULL;
461 }
462 
463 void
464 drop_priv(void)
465 {
466 	struct passwd *pw = NULL;
467 
468 	if (conf.chroot != NULL && conf.user == NULL)
469 		fatal("can't chroot without an user to switch to after.");
470 
471 	if (conf.user != NULL) {
472 		if ((pw = getpwnam(conf.user)) == NULL)
473 			fatal("can't find user %s", conf.user);
474 	}
475 
476 	if (conf.chroot != NULL) {
477 		if (chroot(conf.chroot) != 0 || chdir("/") != 0)
478 			fatal("%s: %s", conf.chroot, strerror(errno));
479 	}
480 
481 	if (pw != NULL) {
482 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
483 			fatal("setresuid(%d): %s", pw->pw_uid,
484 			    strerror(errno));
485 	}
486 
487 	if (getuid() == 0)
488 		LOGW(NULL, "%s",
489 		    "not a good idea to run a network daemon as root");
490 }
491 
492 void
493 usage(const char *me)
494 {
495 	fprintf(stderr,
496 	    "USAGE: %s [-fn] [-c config] | [-6h] [-d certs-dir] [-H host]"
497 	    "       [-p port] [-x cgi] [dir]",
498 	    me);
499 }
500 
501 int
502 main(int argc, char **argv)
503 {
504 	int ch, p[2];
505 	const char *config_path = NULL, *certs_dir = NULL, *hostname = NULL;
506 	int conftest = 0, configless = 0;
507 
508 	init_config();
509 
510 	while ((ch = getopt(argc, argv, "6c:d:fH:hnp:x:")) != -1) {
511 		switch (ch) {
512 		case '6':
513 			conf.ipv6 = 1;
514 			configless = 1;
515 			break;
516 
517 		case 'c':
518 			config_path = optarg;
519 			break;
520 
521 		case 'd':
522 			certs_dir = optarg;
523 			configless = 1;
524 			break;
525 
526 		case 'f':
527 			foreground = 1;
528 			break;
529 
530 		case 'H':
531 			hostname = optarg;
532 			configless = 1;
533 			break;
534 
535 		case 'h':
536 			usage(*argv);
537 			return 0;
538 
539 		case 'n':
540 			conftest = 1;
541 			break;
542 
543 		case 'p':
544 			conf.port = parse_portno(optarg);
545 			configless = 1;
546 			break;
547 
548 		case 'x':
549 			/* drop the starting / (if any) */
550 			if (*optarg == '/')
551 				optarg++;
552 			hosts[0].cgi = optarg;
553 			configless = 1;
554 			break;
555 
556 		default:
557 			usage(*argv);
558 			return 1;
559 		}
560 	}
561 	argc -= optind;
562 	argv += optind;
563 
564 	if (config_path != NULL) {
565 		if (argc > 0 || configless)
566 			fatal("can't specify options is config mode.");
567 
568 		parse_conf(config_path);
569 	} else {
570 		configless = 1;
571 		foreground = 1;
572 
573 		if (hostname == NULL)
574 			hostname = "localhost";
575 		if (certs_dir == NULL)
576 			certs_dir = data_dir();
577 		load_local_cert(hostname, certs_dir);
578 
579 		hosts[0].domain = "*";
580 		hosts[0].locations[0].auto_index = 1;
581 		hosts[0].locations[0].match = "*";
582 
583                 switch (argc) {
584 		case 0:
585 			hosts[0].dir = ".";
586 			break;
587 		case 1:
588 			hosts[0].dir = argv[0];
589 			break;
590 		default:
591 			usage(getprogname());
592 			return 1;
593 		}
594 
595 		LOGN(NULL, "serving %s on port %d", hosts[0].dir, conf.port);
596 	}
597 
598 	if (conftest) {
599 		puts("config OK");
600 		return 0;
601 	}
602 
603 	/* setup tls before dropping privileges: we don't want user
604 	 * to put private certs inside the chroot. */
605 	setup_tls();
606 	drop_priv();
607 
608 	signal(SIGPIPE, SIG_IGN);
609 	signal(SIGCHLD, SIG_IGN);
610 
611 #ifdef SIGINFO
612 	signal(SIGINFO, sig_handler);
613 #endif
614 	signal(SIGUSR2, sig_handler);
615 	signal(SIGHUP, SIG_IGN);
616 
617 	if (!foreground && !configless) {
618 		if (daemon(1, 1) == -1)
619 			fatal("daemon: %s", strerror(errno));
620 	}
621 
622 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
623 		fatal("socketpair: %s", strerror(errno));
624 
625 	switch (fork()) {
626 	case -1:
627 		fatal("fork: %s", strerror(errno));
628 
629 	case 0:			/* child */
630 		close(p[0]);
631 		exfd = p[1];
632 		listener_main();
633 		_exit(0);
634 
635 	default:		/* parent */
636 		close(p[1]);
637 		return executor_main(p[0]);
638 	}
639 }