op public repos

Blob

Date:: Tue Feb 9 22:30:04 2021 UTC
Message:: add `require client ca' rule to require certs signed by a CA
Actions:: History | Blame | Raw File
1 /*
2  * Copyright (c) 2021 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/mman.h>
18 #include <sys/stat.h>
19 
20 #include <netdb.h>
21 
22 #include <assert.h>
23 #include <errno.h>
24 #include <event.h>
25 #include <fcntl.h>
26 #include <fnmatch.h>
27 #include <limits.h>
28 #include <string.h>
29 
30 #include "gmid.h"
31 
32 struct server {
33 	struct client	 clients[MAX_USERS];
34 	struct tls	*ctx;
35 };
36 
37 struct server_events {
38 	struct event	e4;
39 	int		has_ipv6;
40 	struct event	e6;
41 	struct event	sighup;
42 };
43 
44 int connected_clients;
45 
46 static inline void reschedule_read(int, struct client*, statefn);
47 static inline void reschedule_write(int, struct client*, statefn);
48 
49 static int	 check_path(struct client*, const char*, int*);
50 static void	 open_file(struct client*);
51 static void	 load_file(struct client*);
52 static void	 check_for_cgi(struct client*);
53 static void	 handle_handshake(int, short, void*);
54 static char	*strip_path(char*, int);
55 static void	 fmt_sbuf(const char*, struct client*, const char*);
56 static int	 apply_block_return(struct client*);
57 static int	 apply_require_ca(struct client*);
58 static void	 handle_open_conn(int, short, void*);
59 static void	 start_reply(struct client*, int, const char*);
60 static void	 handle_start_reply(int, short, void*);
61 static void	 start_cgi(const char*, const char*, struct client*);
62 static void	 send_file(int, short, void*);
63 static void	 open_dir(struct client*);
64 static void	 redirect_canonical_dir(struct client*);
65 static void	 enter_handle_dirlist(int, short, void*);
66 static void	 handle_dirlist(int, short, void*);
67 static int 	 read_next_dir_entry(struct client*);
68 static void	 send_directory_listing(int, short, void*);
69 static void	 handle_cgi_reply(int, short, void*);
70 static void	 handle_cgi(int, short, void*);
71 static void	 close_conn(int, short, void*);
72 static void	 do_accept(int, short, void*);
73 static void	 handle_sighup(int, short, void*);
74 
75 static inline void
76 reschedule_read(int fd, struct client *c, statefn fn)
77 {
78 	event_once(fd, EV_READ, fn, c, NULL);
79 }
80 
81 void
82 reschedule_write(int fd, struct client *c, statefn fn)
83 {
84 	event_once(fd, EV_WRITE, fn, c, NULL);
85 }
86 
87 const char *
88 vhost_lang(struct vhost *v, const char *path)
89 {
90 	struct location *loc;
91 
92 	if (v == NULL || path == NULL)
93 		return NULL;
94 
95 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
96 		if (loc->lang != NULL) {
97 			if (!fnmatch(loc->match, path, 0))
98 				return loc->lang;
99 		}
100 	}
101 
102 	return v->locations[0].lang;
103 }
104 
105 const char *
106 vhost_default_mime(struct vhost *v, const char *path)
107 {
108 	struct location *loc;
109 	const char *default_mime = "application/octet-stream";
110 
111 	if (v == NULL || path == NULL)
112 		return default_mime;
113 
114 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
115 		if (loc->default_mime != NULL) {
116 			if (!fnmatch(loc->match, path, 0))
117 				return loc->default_mime;
118 		}
119 	}
120 
121 	if (v->locations[0].default_mime != NULL)
122 		return v->locations[0].default_mime;
123 	return default_mime;
124 }
125 
126 const char *
127 vhost_index(struct vhost *v, const char *path)
128 {
129 	struct location *loc;
130 	const char *index = "index.gmi";
131 
132 	if (v == NULL || path == NULL)
133 		return index;
134 
135 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
136 		if (loc->index != NULL) {
137 			if (!fnmatch(loc->match, path, 0))
138 				return loc->index;
139 		}
140 	}
141 
142 	if (v->locations[0].index != NULL)
143 		return v->locations[0].index;
144 	return index;
145 }
146 
147 int
148 vhost_auto_index(struct vhost *v, const char *path)
149 {
150 	struct location *loc;
151 
152 	if (v == NULL || path == NULL)
153 		return 0;
154 
155 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
156 		if (loc->auto_index != 0) {
157 			if (!fnmatch(loc->match, path, 0))
158 				return loc->auto_index == 1;
159 		}
160 	}
161 
162 	return v->locations[0].auto_index == 1;
163 }
164 
165 int
166 vhost_block_return(struct vhost *v, const char *path, int *code, const char **fmt)
167 {
168 	struct location *loc;
169 
170 	if (v == NULL || path == NULL)
171 		return 0;
172 
173 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
174 		if (loc->block_code != 0) {
175 			if (!fnmatch(loc->match, path, 0)) {
176 				*code = loc->block_code;
177 				*fmt = loc->block_fmt;
178 				return 1;
179 			}
180 		}
181 	}
182 
183 	*code = v->locations[0].block_code;
184 	*fmt = v->locations[0].block_fmt;
185 	return v->locations[0].block_code != 0;
186 }
187 
188 int
189 vhost_strip(struct vhost *v, const char *path)
190 {
191 	struct location *loc;
192 
193 	if (v == NULL || path == NULL)
194 		return 0;
195 
196 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
197 		if (loc->strip != 0) {
198 			if (!fnmatch(loc->match, path, 0))
199 				return loc->strip;
200 		}
201 	}
202 
203 	return v->locations[0].strip;
204 }
205 
206 X509_STORE *
207 vhost_require_ca(struct vhost *v, const char *path)
208 {
209 	struct location *loc;
210 
211 	if (v == NULL || path == NULL)
212 		return NULL;
213 
214 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
215 		if (loc->reqca != NULL) {
216 			if (!fnmatch(loc->match, path, 0))
217 				return loc->reqca;
218 		}
219 	}
220 
221 	return v->locations[0].reqca;
222 }
223 
224 static int
225 check_path(struct client *c, const char *path, int *fd)
226 {
227 	struct stat sb;
228 	const char *p;
229 	int flags;
230 
231 	assert(path != NULL);
232 
233 	if (*path == '\0')
234 		p = ".";
235 	else if (*path == '/')
236 		/* in send_dir we add an initial / (to be
237 		 * redirect-friendly), but here we want to skip it */
238 		p = path+1;
239 	else
240 		p = path;
241 
242 	flags = O_RDONLY | O_NOFOLLOW;
243 
244 	if (*fd == -1 && (*fd = openat(c->host->dirfd, p, flags)) == -1)
245 		return FILE_MISSING;
246 
247 	if (fstat(*fd, &sb) == -1) {
248 		log_notice(c, "failed stat for %s: %s", path, strerror(errno));
249 		return FILE_MISSING;
250 	}
251 
252 	if (S_ISDIR(sb.st_mode))
253 		return FILE_DIRECTORY;
254 
255 	if (sb.st_mode & S_IXUSR)
256 		return FILE_EXECUTABLE;
257 
258 	return FILE_EXISTS;
259 }
260 
261 static void
262 open_file(struct client *c)
263 {
264 	switch (check_path(c, c->iri.path, &c->pfd)) {
265 	case FILE_EXECUTABLE:
266 		if (c->host->cgi != NULL && !fnmatch(c->host->cgi, c->iri.path, 0)) {
267 			start_cgi(c->iri.path, "", c);
268 			return;
269 		}
270 
271 		/* fallthrough */
272 
273 	case FILE_EXISTS:
274 		load_file(c);
275 		return;
276 
277 	case FILE_DIRECTORY:
278 		open_dir(c);
279 		return;
280 
281 	case FILE_MISSING:
282 		if (c->host->cgi != NULL && !fnmatch(c->host->cgi, c->iri.path, 0)) {
283 			check_for_cgi(c);
284 			return;
285 		}
286 		start_reply(c, NOT_FOUND, "not found");
287 		return;
288 
289 	default:
290 		/* unreachable */
291 		abort();
292 	}
293 }
294 
295 static void
296 load_file(struct client *c)
297 {
298 	if ((c->len = filesize(c->pfd)) == -1) {
299 		log_err(c, "failed to get file size for %s: %s",
300 		    c->iri.path, strerror(errno));
301 		start_reply(c, TEMP_FAILURE, "internal server error");
302 		return;
303 	}
304 
305 	if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
306 		    c->pfd, 0)) == MAP_FAILED) {
307 		log_err(c, "mmap: %s: %s", c->iri.path, strerror(errno));
308 		start_reply(c, TEMP_FAILURE, "internal server error");
309 		return;
310 	}
311 	c->i = c->buf;
312 	c->next = send_file;
313 	start_reply(c, SUCCESS, mime(c->host, c->iri.path));
314 }
315 
316 /*
317  * the inverse of this algorithm, i.e. starting from the start of the
318  * path + strlen(cgi), and checking if each component, should be
319  * faster.  But it's tedious to write.  This does the opposite: starts
320  * from the end and strip one component at a time, until either an
321  * executable is found or we emptied the path.
322  */
323 static void
324 check_for_cgi(struct client *c)
325 {
326 	char path[PATH_MAX];
327 	char *end;
328 
329 	strlcpy(path, c->iri.path, sizeof(path));
330 	end = strchr(path, '\0');
331 
332 	while (end > path) {
333 		/* go up one level.  UNIX paths are simple and POSIX
334 		 * dirname, with its ambiguities on if the given path
335 		 * is changed or not, gives me headaches. */
336 		while (*end != '/')
337 			end--;
338 		*end = '\0';
339 
340 		switch (check_path(c, path, &c->pfd)) {
341 		case FILE_EXECUTABLE:
342 			start_cgi(path, end+1, c);
343 			return;
344 		case FILE_MISSING:
345 			break;
346 		default:
347 			goto err;
348 		}
349 
350 		*end = '/';
351 		end--;
352 	}
353 
354 err:
355 	start_reply(c, NOT_FOUND, "not found");
356 	return;
357 }
358 
359 void
360 mark_nonblock(int fd)
361 {
362 	int flags;
363 
364 	if ((flags = fcntl(fd, F_GETFL)) == -1)
365 		fatal("fcntl(F_GETFL): %s", strerror(errno));
366 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
367 		fatal("fcntl(F_SETFL): %s", strerror(errno));
368 }
369 
370 static void
371 handle_handshake(int fd, short ev, void *d)
372 {
373 	struct client *c = d;
374 	struct vhost *h;
375 	const char *servname;
376 	const char *parse_err = "unknown error";
377 
378 	switch (tls_handshake(c->ctx)) {
379 	case 0:  /* success */
380 	case -1: /* already handshaked */
381 		break;
382 	case TLS_WANT_POLLIN:
383 		reschedule_read(fd, c, &handle_handshake);
384 		return;
385 	case TLS_WANT_POLLOUT:
386 		reschedule_write(fd, c, &handle_handshake);
387 		return;
388 	default:
389 		/* unreachable */
390 		abort();
391 	}
392 
393 	servname = tls_conn_servername(c->ctx);
394 	if (!puny_decode(servname, c->domain, sizeof(c->domain), &parse_err)) {
395 		log_info(c, "puny_decode: %s", parse_err);
396 		goto err;
397 	}
398 
399 	for (h = hosts; h->domain != NULL; ++h) {
400 		if (!fnmatch(h->domain, c->domain, 0))
401 			break;
402 	}
403 
404 	log_debug(c, "handshake: SNI: \"%s\"; decoded: \"%s\"; matched: \"%s\"",
405 	    servname != NULL ? servname : "(null)",
406 	    c->domain,
407 	    h->domain != NULL ? h->domain : "(null)");
408 
409 	if (h->domain != NULL) {
410 		c->host = h;
411 		handle_open_conn(fd, ev, c);
412 		return;
413 	}
414 
415 err:
416 	if (servname != NULL)
417 		strncpy(c->req, servname, sizeof(c->req));
418 	else
419 		strncpy(c->req, "null", sizeof(c->req));
420 
421 	start_reply(c, BAD_REQUEST, "Wrong/malformed host or missing SNI");
422 }
423 
424 static char *
425 strip_path(char *path, int strip)
426 {
427 	char *t;
428 
429 	while (strip > 0) {
430 		if ((t = strchr(path, '/')) == NULL) {
431 			path = strchr(path, '\0');
432 			break;
433 		}
434 		path = t;
435 		strip--;
436 	}
437 
438 	return path;
439 }
440 
441 static void
442 fmt_sbuf(const char *fmt, struct client *c, const char *path)
443 {
444 	size_t i;
445         char buf[32];
446 
447 	memset(buf, 0, sizeof(buf));
448 	for (i = 0; *fmt; ++fmt) {
449 		if (i == sizeof(buf)-1 || *fmt == '%') {
450 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
451 			memset(buf, 0, sizeof(buf));
452 			i = 0;
453 		}
454 
455 		if (*fmt != '%') {
456 			buf[i++] = *fmt;
457 			continue;
458 		}
459 
460 		switch (*++fmt) {
461 		case '%':
462 			strlcat(c->sbuf, "%", sizeof(c->sbuf));
463 			break;
464 		case 'p':
465 			strlcat(c->sbuf, path, sizeof(c->sbuf));
466 			break;
467 		case 'q':
468 			strlcat(c->sbuf, c->iri.query, sizeof(c->sbuf));
469 			break;
470 		case 'P':
471 			snprintf(buf, sizeof(buf), "%d", conf.port);
472 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
473 			memset(buf, 0, sizeof(buf));
474 			break;
475 		case 'N':
476 			strlcat(c->sbuf, c->domain, sizeof(c->sbuf));
477 			break;
478 		default:
479 			fatal("%s: unknown fmt specifier %c",
480 			    __func__, *fmt);
481 		}
482 	}
483 
484 	if (i != 0)
485 		strlcat(c->sbuf, buf, sizeof(c->sbuf));
486 }
487 
488 /* 1 if a matching `block return' (and apply it), 0 otherwise */
489 static int
490 apply_block_return(struct client *c)
491 {
492 	const char *fmt, *path;
493 	int code;
494 
495 	if (!vhost_block_return(c->host, c->iri.path, &code, &fmt))
496 		return 0;
497 
498 	path = strip_path(c->iri.path, vhost_strip(c->host, c->iri.path));
499 	fmt_sbuf(fmt, c, path);
500 
501 	start_reply(c, code, c->sbuf);
502 	return 1;
503 }
504 
505 /* 1 if matching `require client ca' fails (and apply it), 0 otherwise */
506 static int
507 apply_require_ca(struct client *c)
508 {
509 	X509_STORE	*store;
510 	const uint8_t	*cert;
511 	size_t		 len;
512 
513 	if ((store = vhost_require_ca(c->host, c->iri.path)) == NULL)
514 		return 0;
515 
516 	if (!tls_peer_cert_provided(c->ctx)) {
517 		start_reply(c, CLIENT_CERT_REQ, "client certificate required");
518 		return 1;
519 	}
520 
521 	cert = tls_peer_cert_chain_pem(c->ctx, &len);
522 	if (!validate_against_ca(store, cert, len)) {
523 		start_reply(c, CERT_NOT_AUTH, "certificate not authorised");
524 		return 1;
525 	}
526 
527 	return 0;
528 }
529 
530 static void
531 handle_open_conn(int fd, short ev, void *d)
532 {
533 	struct client *c = d;
534 	const char *parse_err = "invalid request";
535 	char decoded[DOMAIN_NAME_LEN];
536 
537 	bzero(c->req, sizeof(c->req));
538 	bzero(&c->iri, sizeof(c->iri));
539 
540 	switch (tls_read(c->ctx, c->req, sizeof(c->req)-1)) {
541 	case -1:
542 		log_err(c, "tls_read: %s", tls_error(c->ctx));
543 		close_conn(fd, ev, c);
544 		return;
545 
546 	case TLS_WANT_POLLIN:
547 		reschedule_read(fd, c, &handle_open_conn);
548 		return;
549 
550 	case TLS_WANT_POLLOUT:
551 		reschedule_write(fd, c, &handle_open_conn);
552 		return;
553 	}
554 
555 	if (!trim_req_iri(c->req, &parse_err)
556 	    || !parse_iri(c->req, &c->iri, &parse_err)
557 	    || !puny_decode(c->iri.host, decoded, sizeof(decoded), &parse_err)) {
558 		log_info(c, "iri parse error: %s", parse_err);
559 		start_reply(c, BAD_REQUEST, "invalid request");
560 		return;
561 	}
562 
563 	if (c->iri.port_no != conf.port
564 	    || strcmp(c->iri.schema, "gemini")
565 	    || strcmp(decoded, c->domain)) {
566 		start_reply(c, PROXY_REFUSED, "won't proxy request");
567 		return;
568 	}
569 
570 	if (apply_require_ca(c))
571 		return;
572 
573 	if (apply_block_return(c))
574 		return;
575 
576 	if (c->host->entrypoint != NULL) {
577 		start_cgi(c->host->entrypoint, c->iri.path, c);
578 		return;
579 	}
580 
581 	open_file(c);
582 }
583 
584 static void
585 start_reply(struct client *c, int code, const char *meta)
586 {
587 	c->code = code;
588 	c->meta = meta;
589 	handle_start_reply(c->fd, 0, c);
590 }
591 
592 static void
593 handle_start_reply(int fd, short ev, void *d)
594 {
595 	struct client *c = d;
596 	char buf[1030];		/* status + ' ' + max reply len + \r\n\0 */
597 	const char *lang;
598 	size_t len;
599 
600 	lang = vhost_lang(c->host, c->iri.path);
601 
602 	snprintf(buf, sizeof(buf), "%d ", c->code);
603 	strlcat(buf, c->meta, sizeof(buf));
604 	if (!strcmp(c->meta, "text/gemini") && lang != NULL) {
605 		strlcat(buf, "; lang=", sizeof(buf));
606 		strlcat(buf, lang, sizeof(buf));
607 	}
608 
609 	len = strlcat(buf, "\r\n", sizeof(buf));
610 	assert(len < sizeof(buf));
611 
612 	switch (tls_write(c->ctx, buf, len)) {
613 	case -1:
614 		close_conn(fd, ev, c);
615 		return;
616 	case TLS_WANT_POLLIN:
617 		reschedule_read(fd, c, &handle_start_reply);
618 		return;
619 	case TLS_WANT_POLLOUT:
620 		reschedule_write(fd, c, &handle_start_reply);
621 		return;
622 	}
623 
624 	log_request(c, buf, sizeof(buf));
625 
626 	if (c->code != SUCCESS)
627 		close_conn(fd, ev, c);
628 	else
629 		c->next(fd, ev, c);
630 }
631 
632 static void
633 start_cgi(const char *spath, const char *relpath, struct client *c)
634 {
635 	char addr[NI_MAXHOST];
636 	int e;
637 
638 	e = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
639 	    addr, sizeof(addr),
640 	    NULL, 0,
641 	    NI_NUMERICHOST);
642 	if (e != 0)
643 		goto err;
644 
645 	if (!send_iri(exfd, &c->iri)
646 	    || !send_string(exfd, spath)
647 	    || !send_string(exfd, relpath)
648 	    || !send_string(exfd, addr)
649 	    || !send_string(exfd, tls_peer_cert_subject(c->ctx))
650 	    || !send_string(exfd, tls_peer_cert_issuer(c->ctx))
651 	    || !send_string(exfd, tls_peer_cert_hash(c->ctx))
652 	    || !send_time(exfd, tls_peer_cert_notbefore(c->ctx))
653 	    || !send_time(exfd, tls_peer_cert_notafter(c->ctx))
654 	    || !send_vhost(exfd, c->host))
655 		goto err;
656 
657 	close(c->pfd);
658 	if ((c->pfd = recv_fd(exfd)) == -1) {
659 		start_reply(c, TEMP_FAILURE, "internal server error");
660 		return;
661 	}
662 
663 	reschedule_read(c->pfd, c, &handle_cgi_reply);
664 	return;
665 
666 err:
667 	/* fatal("cannot talk to the executor process: %s", strerror(errno)); */
668 	fatal("cannot talk to the executor process");
669 }
670 
671 static void
672 send_file(int fd, short ev, void *d)
673 {
674 	struct client *c = d;
675 	ssize_t ret, len;
676 
677 	len = (c->buf + c->len) - c->i;
678 
679 	while (len > 0) {
680 		switch (ret = tls_write(c->ctx, c->i, len)) {
681 		case -1:
682 			log_err(c, "tls_write: %s", tls_error(c->ctx));
683 			close_conn(fd, ev, c);
684 			return;
685 
686 		case TLS_WANT_POLLIN:
687 			reschedule_read(fd, c, &send_file);
688 			return;
689 
690 		case TLS_WANT_POLLOUT:
691 			reschedule_write(fd, c, &send_file);
692 			return;
693 
694 		default:
695 			c->i += ret;
696 			len -= ret;
697 			break;
698 		}
699 	}
700 
701 	close_conn(fd, ev, c);
702 }
703 
704 static void
705 open_dir(struct client *c)
706 {
707 	size_t len;
708 	int dirfd;
709 	char *before_file;
710 
711 	len = strlen(c->iri.path);
712 	if (len > 0 && !ends_with(c->iri.path, "/")) {
713 		redirect_canonical_dir(c);
714 		return;
715 	}
716 
717 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
718 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
719 	if (!ends_with(c->sbuf, "/"))
720 		strlcat(c->sbuf, "/", sizeof(c->sbuf));
721 	before_file = strchr(c->sbuf, '\0');
722 	len = strlcat(c->sbuf, vhost_index(c->host, c->iri.path),
723 	    sizeof(c->sbuf));
724 	if (len >= sizeof(c->sbuf)) {
725 		start_reply(c, TEMP_FAILURE, "internal server error");
726 		return;
727 	}
728 
729 	c->iri.path = c->sbuf;
730 
731 	/* close later unless we have to generate the dir listing */
732 	dirfd = c->pfd;
733 	c->pfd = -1;
734 
735 	switch (check_path(c, c->iri.path, &c->pfd)) {
736 	case FILE_EXECUTABLE:
737 		if (c->host->cgi != NULL && !fnmatch(c->host->cgi, c->iri.path, 0)) {
738 			start_cgi(c->iri.path, "", c);
739 			break;
740 		}
741 
742 		/* fallthrough */
743 
744 	case FILE_EXISTS:
745                 load_file(c);
746 		break;
747 
748 	case FILE_DIRECTORY:
749 		start_reply(c, TEMP_REDIRECT, c->sbuf);
750 		break;
751 
752 	case FILE_MISSING:
753 		*before_file = '\0';
754 
755 		if (!vhost_auto_index(c->host, c->iri.path)) {
756 			start_reply(c, NOT_FOUND, "not found");
757 			break;
758 		}
759 
760 		c->pfd = dirfd;
761 		c->next = enter_handle_dirlist;
762 
763 		if ((c->dir = fdopendir(c->pfd)) == NULL) {
764 			log_err(c, "fdopendir(%d) (vhost:%s) %s: %s",
765 			    c->pfd, c->host->domain, c->iri.path, strerror(errno));
766 			start_reply(c, TEMP_FAILURE, "internal server error");
767 			return;
768 		}
769 		c->off = 0;
770 
771                 start_reply(c, SUCCESS, "text/gemini");
772 		return;
773 
774 	default:
775 		/* unreachable */
776 		abort();
777 	}
778 
779 	close(dirfd);
780 }
781 
782 static void
783 redirect_canonical_dir(struct client *c)
784 {
785 	size_t len;
786 
787 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
788 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
789 	len = strlcat(c->sbuf, "/", sizeof(c->sbuf));
790 
791 	if (len >= sizeof(c->sbuf)) {
792 		start_reply(c, TEMP_FAILURE, "internal server error");
793 		return;
794 	}
795 
796 	start_reply(c, TEMP_REDIRECT, c->sbuf);
797 }
798 
799 static void
800 enter_handle_dirlist(int fd, short ev, void *d)
801 {
802 	struct client *c = d;
803 	char b[PATH_MAX];
804 	size_t l;
805 
806 	strlcpy(b, c->iri.path, sizeof(b));
807 	l = snprintf(c->sbuf, sizeof(c->sbuf),
808 	    "# Index of %s\n\n", b);
809 	if (l >= sizeof(c->sbuf)) {
810 		/* this is impossible, given that we have enough space
811 		 * in c->sbuf to hold the ancilliary string plus the
812 		 * full path; but it wouldn't read nice without some
813 		 * error checking, and I'd like to avoid a strlen. */
814 		close_conn(fd, ev, c);
815 		return;
816 	}
817 
818 	c->len = l;
819 	handle_dirlist(fd, ev, c);
820 }
821 
822 static void
823 handle_dirlist(int fd, short ev, void *d)
824 {
825 	struct client *c = d;
826 	ssize_t r;
827 
828 	while (c->len > 0) {
829 		switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
830 		case -1:
831 			close_conn(fd, ev, c);
832 			return;
833 		case TLS_WANT_POLLOUT:
834 			reschedule_read(fd, c, &handle_dirlist);
835 			return;
836 		case TLS_WANT_POLLIN:
837 			reschedule_write(fd, c, &handle_dirlist);
838 			return;
839 		default:
840 			c->off += r;
841 			c->len -= r;
842 		}
843 	}
844 
845 	send_directory_listing(fd, ev, c);
846 }
847 
848 static int
849 read_next_dir_entry(struct client *c)
850 {
851 	struct dirent *d;
852 
853 	do {
854 		errno = 0;
855 		if ((d = readdir(c->dir)) == NULL) {
856 			if (errno != 0)
857 				log_err(c, "readdir: %s", strerror(errno));
858 			return 0;
859 		}
860 	} while (!strcmp(d->d_name, "."));
861 
862 	/* XXX: url escape */
863 	snprintf(c->sbuf, sizeof(c->sbuf), "=> %s %s\n",
864 	    d->d_name, d->d_name);
865 	c->len = strlen(c->sbuf);
866 	c->off = 0;
867 
868 	return 1;
869 }
870 
871 static void
872 send_directory_listing(int fd, short ev, void *d)
873 {
874 	struct client *c = d;
875 	ssize_t r;
876 
877 	while (1) {
878 		if (c->len == 0) {
879 			if (!read_next_dir_entry(c))
880 				goto end;
881 		}
882 
883 		while (c->len > 0) {
884 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
885 			case -1:
886 				goto end;
887 
888 			case TLS_WANT_POLLOUT:
889 				reschedule_read(fd, c, &send_directory_listing);
890 				return;
891 
892 			case TLS_WANT_POLLIN:
893 				reschedule_write(fd, c, &send_directory_listing);
894 				return;
895 
896 			default:
897 				c->off += r;
898 				c->len -= r;
899 				break;
900 			}
901 		}
902 	}
903 
904 end:
905 	close_conn(fd, ev, d);
906 }
907 
908 /* accumulate the meta line from the cgi script. */
909 static void
910 handle_cgi_reply(int fd, short ev, void *d)
911 {
912 	struct client *c = d;
913 	void	*buf, *e;
914 	size_t	 len;
915 	ssize_t	 r;
916 
917 
918 	buf = c->sbuf + c->len;
919 	len = sizeof(c->sbuf) - c->len;
920 
921 	r = read(c->pfd, buf, len);
922 	if (r == 0 || r == -1) {
923 		start_reply(c, CGI_ERROR, "CGI error");
924 		return;
925 	}
926 
927 	c->len += r;
928 
929 	/* TODO: error if the CGI script don't reply correctly */
930 	e = strchr(c->sbuf, '\n');
931 	if (e != NULL || c->len == sizeof(c->sbuf)) {
932 		log_request(c, c->sbuf, c->len);
933 
934 		c->off = 0;
935 		handle_cgi(fd, ev, c);
936 		return;
937 	}
938 
939 	reschedule_read(fd, c, &handle_cgi_reply);
940 }
941 
942 static void
943 handle_cgi(int fd, short ev, void *d)
944 {
945 	struct client *c = d;
946 	ssize_t r;
947 
948 	while (1) {
949 		if (c->len == 0) {
950 			switch (r = read(c->pfd, c->sbuf, sizeof(c->sbuf))) {
951 			case 0:
952 				goto end;
953 			case -1:
954 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
955 					reschedule_read(c->pfd, c, &handle_cgi);
956 					return;
957 				}
958 				goto end;
959 			default:
960 				c->len = r;
961 				c->off = 0;
962 			}
963 		}
964 
965 		while (c->len > 0) {
966 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
967 			case -1:
968 				goto end;
969 
970 			case TLS_WANT_POLLOUT:
971 				reschedule_read(c->fd, c, &handle_cgi);
972 				return;
973 
974 			case TLS_WANT_POLLIN:
975 				reschedule_write(c->fd, c, &handle_cgi);
976 				return;
977 
978 			default:
979                                 c->off += r;
980 				c->len -= r;
981 				break;
982 			}
983 		}
984 	}
985 
986 end:
987 	close_conn(c->fd, ev, d);
988 }
989 
990 static void
991 close_conn(int fd, short ev, void *d)
992 {
993 	struct client *c = d;
994 
995 	switch (tls_close(c->ctx)) {
996 	case TLS_WANT_POLLIN:
997 		reschedule_read(fd, c, &close_conn);
998 		return;
999 	case TLS_WANT_POLLOUT:
1000 		reschedule_read(fd, c, &close_conn);
1001 		return;
1002 	}
1003 
1004 	connected_clients--;
1005 
1006 	tls_free(c->ctx);
1007 	c->ctx = NULL;
1008 
1009 	if (c->buf != MAP_FAILED)
1010 		munmap(c->buf, c->len);
1011 
1012 	if (c->pfd != -1)
1013 		close(c->pfd);
1014 
1015 	if (c->dir != NULL)
1016 		closedir(c->dir);
1017 
1018 	close(c->fd);
1019 	c->fd = -1;
1020 }
1021 
1022 static void
1023 do_accept(int sock, short et, void *d)
1024 {
1025 	struct client *c;
1026 	struct server *s = d;
1027 	struct sockaddr_storage addr;
1028 	struct sockaddr *saddr;
1029 	socklen_t len;
1030 	int i, fd;
1031 
1032 	(void)et;
1033 
1034 
1035 	saddr = (struct sockaddr*)&addr;
1036 	len = sizeof(addr);
1037 	if ((fd = accept4(sock, saddr, &len, SOCK_NONBLOCK)) == -1) {
1038 		if (errno == EWOULDBLOCK || errno == EAGAIN)
1039 			return;
1040 		fatal("accept: %s", strerror(errno));
1041 	}
1042 
1043 	for (i = 0; i < MAX_USERS; ++i) {
1044 		c = &s->clients[i];
1045 		if (c->fd == -1) {
1046 			memset(c, 0, sizeof(*c));
1047 			if (tls_accept_socket(s->ctx, &c->ctx, fd) == -1)
1048 				break; /* goodbye fd! */
1049 
1050 			c->fd = fd;
1051 			c->pfd = -1;
1052 			c->buf = MAP_FAILED;
1053 			c->dir = NULL;
1054 			c->addr = addr;
1055 
1056 			reschedule_read(fd, c, &handle_handshake);
1057 			connected_clients++;
1058 			return;
1059 		}
1060 	}
1061 
1062 	close(fd);
1063 }
1064 
1065 static void
1066 handle_sighup(int fd, short ev, void *d)
1067 {
1068 	struct server_events *events = d;
1069 
1070 	(void)fd;
1071 	(void)ev;
1072 
1073 	event_del(&events->e4);
1074 	if (events->has_ipv6)
1075 		event_del(&events->e6);
1076 	signal_del(&events->sighup);
1077 }
1078 
1079 static void
1080 handle_siginfo(int fd, short ev, void *d)
1081 {
1082 	(void)fd;
1083 	(void)ev;
1084 	(void)d;
1085 
1086 	log_info(NULL, "%d connected clients", connected_clients);
1087 }
1088 
1089 void
1090 loop(struct tls *ctx, int sock4, int sock6)
1091 {
1092 	struct server_events events;
1093 	struct server server;
1094 	struct event info;
1095 	size_t i;
1096 
1097 	event_init();
1098 
1099 	memset(&events, 0, sizeof(events));
1100 	memset(&server, 0, sizeof(server));
1101 	for (i = 0; i < MAX_USERS; ++i)
1102 		server.clients[i].fd = -1;
1103 
1104 	event_set(&events.e4, sock4, EV_READ | EV_PERSIST, &do_accept, &server);
1105 	event_add(&events.e4, NULL);
1106 
1107 	if (sock6 != -1) {
1108 		events.has_ipv6 = 1;
1109 		event_set(&events.e6, sock6, EV_READ | EV_PERSIST, &do_accept, &server);
1110 		event_add(&events.e6, NULL);
1111 	}
1112 
1113 	signal_set(&events.sighup, SIGHUP, &handle_sighup, &events);
1114 	signal_add(&events.sighup, NULL);
1115 
1116 #ifdef SIGINFO
1117 	signal_set(&info, SIGINFO, &handle_siginfo, NULL);
1118 	signal_add(&info, NULL);
1119 #endif
1120 	signal_set(&info, SIGUSR2, &handle_siginfo, NULL);
1121 	signal_add(&info, NULL);
1122 
1123 	server.ctx = ctx;
1124 
1125 	sandbox();
1126 	event_dispatch();
1127 	_exit(0);
1128 }