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Date:: Thu Apr 13 21:46:22 2023 UTC
Message:: properly initialize the `lang' buffer otherwise we end up using stack garbage when the gemini server doesn't send a `lang' attribute. Problem reported by Javier Bravo, thanks!
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1 /*
2  * Copyright (c) 2022 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2006 - 2015 Reyk Floeter <reyk@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 #include <sys/socket.h>
22 #include <sys/uio.h>
23 
24 #include <netinet/in.h>
25 #include <arpa/inet.h>
26 #include <netdb.h>
27 
28 #include <asr.h>
29 #include <ctype.h>
30 #include <errno.h>
31 #include <event.h>
32 #include <fnmatch.h>
33 #include <limits.h>
34 #include <stdlib.h>
35 #include <stdint.h>
36 #include <stdio.h>
37 #include <string.h>
38 #include <imsg.h>
39 #include <tls.h>
40 #include <unistd.h>
41 
42 #include "config.h"
43 #include "log.h"
44 #include "proc.h"
45 #include "tmpl.h"
46 
47 #include "galileo.h"
48 
49 #define MINIMUM(a, b)	((a) < (b) ? (a) : (b))
50 
51 #if HAVE_LIBEVENT2
52 # define G_TOUT(t)	((t).tv_sec)
53 #else
54 # define G_TOUT(t)	(t)
55 #endif
56 
57 /* provided by OpenBSD' base libevent but not in any header? */
58 extern void	 bufferevent_read_pressure_cb(struct evbuffer *, size_t,
59 		    size_t, void *);
60 
61 void	proxy_init(struct privsep *, struct privsep_proc *, void *);
62 int	proxy_launch(struct galileo *);
63 void	proxy_inflight_dec(const char *);
64 int	proxy_dispatch_parent(int, struct privsep_proc *, struct imsg *);
65 int	proxy_resurl(struct client *, const char *, char *, size_t);
66 void	proxy_translate_gemtext(struct client *);
67 void	proxy_resolved(struct asr_result *, void *);
68 void	proxy_connect(int, short, void *);
69 int	proxy_start_reply(struct client *, int, const char *);
70 void	proxy_read(struct bufferevent *, void *);
71 void	proxy_write(struct bufferevent *, void *);
72 void	proxy_error(struct bufferevent *, short, void *);
73 int	proxy_bufferevent_add(struct event *, int);
74 void	proxy_tls_writecb(int, short, void *);
75 void	proxy_tls_readcb(int, short, void *);
76 
77 static struct privsep_proc procs[] = {
78 	{ "parent",	PROC_PARENT, proxy_dispatch_parent },
79 };
80 
81 volatile int proxy_clients;
82 volatile int proxy_inflight;
83 uint32_t proxy_fcg_id;
84 
85 void
86 proxy(struct privsep *ps, struct privsep_proc *p)
87 {
88 	proc_run(ps, p, procs, nitems(procs), proxy_init, NULL);
89 }
90 
91 void
92 proxy_init(struct privsep *ps, struct privsep_proc *p, void *arg)
93 {
94 	if (config_init(ps->ps_env) == -1)
95 		fatal("failed to initialize configuration");
96 
97 	/* We use a custom shutdown callback */
98 	/* p->p_shutdown = proxy_shutdown */
99 
100 	if (pledge("stdio recvfd unix inet dns", NULL) == -1)
101 		fatal("pledge");
102 }
103 
104 int
105 proxy_launch(struct galileo *env)
106 {
107 	event_add(&env->sc_evsock, NULL);
108 	return (0);
109 }
110 
111 void
112 proxy_purge(struct proxy *pr)
113 {
114 	free(pr);
115 }
116 
117 void
118 proxy_inflight_dec(const char *why)
119 {
120 	proxy_inflight--;
121 	log_debug("%s: inflight decremented, now %d, %s",
122 	    __func__, proxy_inflight, why);
123 }
124 
125 int
126 proxy_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
127 {
128 	struct privsep	*ps = p->p_ps;
129 	struct galileo	*env = ps->ps_env;
130 
131 	switch (imsg->hdr.type) {
132 	case IMSG_CFG_SRV:
133 		if (config_getproxy(env, imsg) == -1)
134 			fatal("config_getproxy");
135 		break;
136 	case IMSG_CFG_SOCK:
137 		/* XXX: improve */
138 
139 		env->sc_sock_fd = config_getsock(env, imsg);
140 		if (env->sc_sock_fd == -1)
141 			fatal("config_getsock");
142 
143 		event_set(&env->sc_evsock, env->sc_sock_fd,
144 		    EV_READ | EV_PERSIST, fcgi_accept, env);
145 		evtimer_set(&env->sc_evpause, fcgi_accept, env);
146 		break;
147 	case IMSG_CFG_DONE:
148 		config_getcfg(env, imsg);
149 		proxy_launch(env);
150 		break;
151 	case IMSG_CTL_START:
152 		break;
153 	case IMSG_CTL_RESET:
154 		config_getreset(env, imsg);
155 		break;
156 	default:
157 		return (-1);
158 	}
159 
160 	return (0);
161 }
162 
163 static int
164 portok(const char **url, struct client *clt)
165 {
166 	const char		*u = *url;
167 	const char		*port = clt->clt_pc->proxy_port;
168 	size_t			 len;
169 
170 	len = strlen(port);
171 
172 	if (*u == '\0' || *u == '/' || *u == '?' || *u == '#')
173 		return (1);
174 	if (*u != ':')
175 		return (0);
176 	u++;
177 	if (strncmp(u, port, len) != 0)
178 		return (0);
179 	u += len;
180 	if (*u != '\0' && *u != '/' && *u != '?' && *u != '#')
181 		return (0);
182 	*url = u;
183 	return (1);
184 }
185 
186 int
187 proxy_resurl(struct client *clt, const char *url, char *buf, size_t len)
188 {
189 	const char		*tmp;
190 	size_t			 l;
191 
192 	if (clt->clt_server_name == NULL)
193 		return (-1);
194 
195 	l = strlen(clt->clt_server_name);
196 
197 	if (len == 0) {
198 		log_warn("%s: zero-sized buffer!", __func__);
199 		return (-1);
200 	}
201 
202 	/* look if it's an absolute URI */
203 	if (strncmp(url, "//", 2) == 0) {
204 		tmp = url + 2;
205 		if (strncmp(tmp, clt->clt_server_name, l) != 0)
206 			goto done;
207 
208 		tmp += l;
209 		if (!portok(&tmp, clt))
210 			goto done;
211 		url = tmp;
212 	} else if (strncmp(url, "gemini://", 9) == 0) {
213 		tmp = url + 9;
214 		if (strncmp(tmp, clt->clt_server_name, l) != 0)
215 			goto done;
216 
217 		tmp += l;
218 		if (!portok(&tmp, clt))
219 			goto done;
220 		url = tmp;
221 	} else {
222 		tmp = url;
223 		while (isalpha((unsigned char)*tmp) || *tmp == '+')
224 			tmp++;
225 		if (strncmp(tmp, "://", 3) == 0)
226 			goto done;
227 	}
228 
229 	/* maybe it's an absolute path? */
230 	if (*url == '\0' || *url == '/') {
231 		if (strlcpy(buf, clt->clt_script_name, len) >= len)
232 			return (-1);
233 		if (strlcat(buf, url + 1, len) >= len)
234 			return (-1);
235 		return (0);
236 	}
237 
238 	/* otherwise, leave it as it is */
239  done:
240 	if (strlcpy(buf, url, len) >= len)
241 		return (-1);
242 	return (0);
243 }
244 
245 static inline int
246 match_image_heur(const char *url)
247 {
248 	return (fnmatch("*.jpg", url, 0) == 0 ||
249 	    fnmatch("*.jpeg", url, 0) == 0 ||
250 	    fnmatch("*.gif", url, 0) == 0 ||
251 	    fnmatch("*.png", url, 0) == 0 ||
252 	    fnmatch("*.svg", url, 0) == 0 ||
253 	    fnmatch("*.webp", url, 0) == 0);
254 }
255 
256 static int
257 gemtext_translate_line(struct client *clt, char *line)
258 {
259 	char		 buf[1025];
260 	char		*url;
261 
262 	/* preformatted line / closing */
263 	if (clt->clt_translate & TR_PRE) {
264 		if (!strncmp(line, "```", 3)) {
265 			clt->clt_translate &= ~TR_PRE;
266 			return (tp_pre_close(clt->clt_tp));
267 		}
268 
269 		if (tp_htmlescape(clt->clt_tp, line) == -1)
270 			return (-1);
271 		return (clt_putc(clt, '\n'));
272 	}
273 
274 	/* bullet */
275 	if (!strncmp(line, "* ", 2)) {
276 		if (clt->clt_translate & TR_NAV) {
277 			if (clt_puts(clt, "</ul></nav>") == -1)
278 				return (-1);
279 			clt->clt_translate &= ~TR_NAV;
280 		}
281 
282 		if (!(clt->clt_translate & TR_LIST)) {
283 			if (clt_puts(clt, "<ul>") == -1)
284 				return (-1);
285 			clt->clt_translate |= TR_LIST;
286 		}
287 
288 		if (clt_puts(clt, "<li>") == -1 ||
289 		    tp_htmlescape(clt->clt_tp, line + 2) == -1 ||
290 		    clt_puts(clt, "</li>") == -1)
291 			return (-1);
292 		return (0);
293 	}
294 
295 	if (clt->clt_translate & TR_LIST) {
296 		if (clt_puts(clt, "</ul>") == -1)
297 			return (-1);
298 		clt->clt_translate &= ~TR_LIST;
299 	}
300 
301 	/* link */
302 	if (!strncmp(line, "=>", 2)) {
303 		char *label;
304 
305 		line += 2;
306 		line += strspn(line, " \t");
307 
308 		label = line + strcspn(line, " \t");
309 		if (*label == '\0')
310 			label = line;
311 		else {
312 			*label++ = '\0';
313 			label += strspn(label, " \t");
314 			if (*label == '\0')
315 				label = line;
316 		}
317 
318 		if (proxy_resurl(clt, line, buf, sizeof(buf)) == 0)
319 			url = buf;
320 		else
321 			url = line; /* leave the URL as it is */
322 
323 		if (!(clt->clt_pc->flags & PROXY_NO_IMGPRV) &&
324 		    match_image_heur(url)) {
325 			if (clt->clt_translate & TR_NAV) {
326 				if (clt_puts(clt, "</ul></nav>") == -1)
327 					return (-1);
328 				clt->clt_translate &= ~TR_NAV;
329 			}
330 
331 			if (tp_figure(clt->clt_tp, url, label) == -1)
332 				return (-1);
333 
334 			return (0);
335 		}
336 
337 		if (!(clt->clt_translate & TR_NAV)) {
338 			if (clt_puts(clt, "<nav><ul>") == -1)
339 				return (-1);
340 			clt->clt_translate |= TR_NAV;
341 		}
342 
343 		if (clt_puts(clt, "<li><a href='") == -1)
344 			return (-1);
345 
346 		if (tp_urlescape(clt->clt_tp, url) == -1 ||
347 		    clt_puts(clt, "'>") == -1 ||
348 		    tp_htmlescape(clt->clt_tp, label) == -1 ||
349 		    clt_puts(clt, "</a></li>") == -1)
350 			return (-1);
351 
352 		return (0);
353 	}
354 
355 	if (clt->clt_translate & TR_NAV) {
356 		if (clt_puts(clt, "</ul></nav>") == -1)
357 			return (-1);
358 		clt->clt_translate &= ~TR_NAV;
359 	}
360 
361 	/* pre opening */
362 	if (!strncmp(line, "```", 3)) {
363 		line += 3;
364 		line += strspn(line, " \t");
365 
366 		clt->clt_translate |= TR_PRE;
367 		return (tp_pre_open(clt->clt_tp, line));
368 	}
369 
370 	/* citation block */
371 	if (*line == '>') {
372 		if (clt_puts(clt, "<blockquote>") == -1 ||
373 		    tp_htmlescape(clt->clt_tp, line + 1) == -1 ||
374 		    clt_puts(clt, "</blockquote>") == -1)
375 			return (-1);
376 		return (0);
377 	}
378 
379 	/* headings */
380 	if (!strncmp(line, "###", 3)) {
381 		if (clt_puts(clt, "<h3>") == -1 ||
382 		    tp_htmlescape(clt->clt_tp, line + 3) == -1 ||
383 		    clt_puts(clt, "</h3>") == -1)
384 			return (-1);
385 		return (0);
386 	}
387 	if (!strncmp(line, "##", 2)) {
388 		if (clt_puts(clt, "<h2>") == -1 ||
389 		    tp_htmlescape(clt->clt_tp, line + 2) == -1 ||
390 		    clt_puts(clt, "</h2>") == -1)
391 			return (-1);
392 		return (0);
393 	}
394 	if (!strncmp(line, "#", 1)) {
395 		if (clt_puts(clt, "<h1>") == -1 ||
396 		    tp_htmlescape(clt->clt_tp, line + 1) == -1 ||
397 		    clt_puts(clt, "</h1>") == -1)
398 			return (-1);
399 		return (0);
400 	}
401 
402 	/* Not following strictly the gemini specification... */
403 	if (*line == '\0')
404 		return (0);
405 
406 	/* paragraph */
407 	if (clt_puts(clt, "<p>") == -1 ||
408 	    tp_htmlescape(clt->clt_tp, line) == -1 ||
409 	    clt_puts(clt, "</p>") == -1)
410 		return (-1);
411 
412 	return (0);
413 }
414 
415 void
416 proxy_translate_gemtext(struct client *clt)
417 {
418 	struct bufferevent	*bev = clt->clt_bev;
419 	struct evbuffer		*src = EVBUFFER_INPUT(bev);
420 	char			*line;
421 	size_t			 len;
422 	int			 r;
423 
424 	for (;;) {
425 		line = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF);
426 		if (line == NULL)
427 			return;
428 
429 		r = gemtext_translate_line(clt, line);
430 		free(line);
431 		if (r == -1)
432 			return;
433 	}
434 }
435 
436 struct proxy_config *
437 proxy_match(struct galileo *env, const char *name)
438 {
439 	struct proxy		*pr;
440 
441 	if (name == NULL)
442 		return (NULL);
443 
444 	TAILQ_FOREACH(pr, &env->sc_proxies, pr_entry) {
445 		if (!strcmp(name, pr->pr_conf.host))
446 			return (&pr->pr_conf);
447 	}
448 
449 	return (NULL);
450 }
451 
452 int
453 proxy_start_request(struct galileo *env, struct client *clt)
454 {
455 	struct addrinfo		 hints;
456 	struct asr_query	*query;
457 	int			 r;
458 	char			*url;
459 
460 	if (clt->clt_path_info == NULL) {
461 		log_warnx("PATH_INFO not defined!");
462 		if (proxy_start_reply(clt, 501, "text/html") == -1)
463 			return (-1);
464 		if (tp_error(clt->clt_tp, -1, "internal server error") == -1)
465 			return (-1);
466 		return (fcgi_end_request(clt, 1));
467 	}
468 
469 	if ((clt->clt_pc = proxy_match(env, clt->clt_server_name)) == NULL) {
470 		if (proxy_start_reply(clt, 501, "text/html") == -1)
471 			return (-1);
472 		if (tp_error(clt->clt_tp, -1, "unknown server") == -1)
473 			return (-1);
474 		return (fcgi_end_request(clt, 1));
475 	}
476 
477 	if (clt->clt_bodylen != 0 && clt->clt_body == NULL) {
478 		if (proxy_start_reply(clt, 400, "text/html") == -1)
479 			return (-1);
480 		if (tp_error(clt->clt_tp, -1, "bad request") == -1)
481 			return (-1);
482 		return (fcgi_end_request(clt, 1));
483 	}
484 
485 	if (clt->clt_body) {
486 		r = asprintf(&url, "%s%s?%s", clt->clt_script_name,
487 		    clt->clt_path_info + 1, clt->clt_body);
488 		if (r == -1)
489 			return (fcgi_end_request(clt, 1));
490 
491 		if (proxy_start_reply(clt, 302, url) == -1 ||
492 		    fcgi_end_request(clt, 1) == -1) {
493 			free(url);
494 			return (-1);
495 		}
496 		free(url);
497 		return (0);
498 	}
499 
500 	memset(&hints, 0, sizeof(hints));
501 	hints.ai_family = AF_UNSPEC;
502 	hints.ai_socktype = SOCK_STREAM;
503 
504 	query = getaddrinfo_async(clt->clt_pc->proxy_addr,
505 	    clt->clt_pc->proxy_port, &hints, NULL);
506 	if (query == NULL) {
507 		log_warn("getaddrinfo_async");
508 		return (fcgi_abort_request(clt));
509 	}
510 
511 	clt->clt_evasr = event_asr_run(query, proxy_resolved, clt);
512 	if (clt->clt_evasr == NULL) {
513 		log_warn("event_asr_run");
514 		asr_abort(query);
515 		return (fcgi_abort_request(clt));
516 	}
517 
518 	return (0);
519 }
520 
521 void
522 proxy_resolved(struct asr_result *res, void *d)
523 {
524 	struct client		*clt = d;
525 	struct proxy_config	*pc = clt->clt_pc;
526 
527 	clt->clt_evasr = NULL;
528 
529 	if (res->ar_gai_errno != 0) {
530 		log_warnx("failed to resolve %s:%s: %s",
531 		    pc->proxy_addr, pc->proxy_port,
532 		    gai_strerror(res->ar_gai_errno));
533 		if (proxy_start_reply(clt, 501, "text/html") == -1)
534 			return;
535 		if (tp_error(clt->clt_tp, -1, "Can't resolve host") == -1)
536 			return;
537 		fcgi_end_request(clt, 1);
538 		return;
539 	}
540 
541 	clt->clt_addrinfo = res->ar_addrinfo;
542 	clt->clt_p = clt->clt_addrinfo;
543 	proxy_connect(-1, 0, clt);
544 }
545 
546 void
547 proxy_connect(int fd, short ev, void *d)
548 {
549 	struct client		*clt = d;
550 	struct evbuffer		*out;
551 	struct addrinfo		*p;
552 	struct tls_config	*conf;
553 	struct timeval		 conntv = {5, 0};
554 	int			 err = 0;
555 	socklen_t		 len = sizeof(err);
556 
557 again:
558 	if (clt->clt_p == NULL)
559 		goto err;
560 
561 	if (clt->clt_fd != -1) {
562 		if (getsockopt(clt->clt_fd, SOL_SOCKET, SO_ERROR, &err, &len)
563 		    == -1)
564 			goto err;
565 		if (err != 0) {
566 			errno = err;
567 			goto err;
568 		}
569 		goto done;
570 	}
571 
572 	p = clt->clt_p;
573 	clt->clt_fd = socket(p->ai_family, p->ai_socktype | SOCK_NONBLOCK,
574 	    p->ai_protocol);
575 	if (clt->clt_fd == -1) {
576 		clt->clt_p = clt->clt_p->ai_next;
577 		goto again;
578 	}
579 
580 	if (connect(clt->clt_fd, p->ai_addr, p->ai_addrlen) == 0)
581 		goto done;
582 
583 	clt->clt_evconn_live = 1;
584 	event_set(&clt->clt_evconn, clt->clt_fd, EV_WRITE, proxy_connect, clt);
585 	event_add(&clt->clt_evconn, &conntv);
586 	return;
587 
588 done:
589 	clt->clt_evconn_live = 0;
590 	freeaddrinfo(clt->clt_addrinfo);
591 	clt->clt_addrinfo = clt->clt_p = NULL;
592 
593 	clt->clt_bev = bufferevent_new(clt->clt_fd, proxy_read, proxy_write,
594 	    proxy_error, clt);
595 	if (clt->clt_bev == NULL) {
596 		log_warn("bufferevent_new");
597 		goto err;
598 	}
599 
600 	if (!(clt->clt_pc->flags & PROXY_NO_TLS)) {
601 		/* initialize TLS for Gemini */
602 		if ((conf = tls_config_new()) == NULL) {
603 			log_warn("tls_config_new failed");
604 			goto err;
605 		}
606 
607 		tls_config_insecure_noverifycert(conf);
608 
609 		if ((clt->clt_ctx = tls_client()) == NULL) {
610 			log_warnx("tls_client failed");
611 			tls_config_free(conf);
612 			goto err;
613 		}
614 
615 		if (tls_configure(clt->clt_ctx, conf) == -1) {
616 			log_warnx("tls_configure failed");
617 			tls_config_free(conf);
618 			goto err;
619 		}
620 
621 		tls_config_free(conf);
622 
623 		if (tls_connect_socket(clt->clt_ctx, clt->clt_fd,
624 			clt->clt_pc->proxy_name) == -1) {
625 			log_warnx("tls_connect_socket failed");
626 			goto err;
627 		}
628 
629 		event_set(&clt->clt_bev->ev_read, clt->clt_fd, EV_READ,
630 		    proxy_tls_readcb, clt->clt_bev);
631 		event_set(&clt->clt_bev->ev_write, clt->clt_fd, EV_WRITE,
632 		    proxy_tls_writecb, clt->clt_bev);
633 
634 #if HAVE_LIBEVENT2
635 		evbuffer_unfreeze(clt->clt_bev->input, 0);
636 		evbuffer_unfreeze(clt->clt_bev->output, 1);
637 #endif
638 	}
639 
640 	/* bufferevent_settimeout(); */
641 	bufferevent_enable(clt->clt_bev, EV_READ|EV_WRITE);
642 
643 	/* TODO: compute the URL */
644 	out = EVBUFFER_OUTPUT(clt->clt_bev);
645 	if (evbuffer_add_printf(out, "gemini://%s/%s",
646 	    clt->clt_pc->proxy_name, clt->clt_path_info) == -1) {
647 		log_warn("bufferevent_printf failed");
648 		goto err;
649 	}
650 
651 	if (clt->clt_query &&
652 	    evbuffer_add_printf(out, "?%s", clt->clt_query) == -1) {
653 		log_warn("bufferevent_printf failed");
654 		goto err;
655 	}
656 
657 	if (evbuffer_add(out, "\r\n", 2) == -1) {
658 		log_warn("bufferevent_add failed");
659 		goto err;
660 	}
661 
662 	return;
663 
664 err:
665 	log_warn("failed to connect to %s:%s",
666 	    clt->clt_pc->proxy_addr, clt->clt_pc->proxy_port);
667 	if (proxy_start_reply(clt, 501, "text/html") == -1)
668 		return;
669 	if (tp_error(clt->clt_tp, -1, "Can't connect") == -1)
670 		return;
671 	fcgi_end_request(clt, 1);
672 }
673 
674 static inline int
675 parse_mime(struct client *clt, char *mime, char *lang, size_t len)
676 {
677 	char			*t, *semi;
678 
679 	memset(lang, 0, len);
680 
681 	if (strncmp(mime, "text/gemini", 11) != 0)
682 		return (0);
683 
684 	clt->clt_translate = TR_ENABLED;
685 
686 	if ((mime = strchr(mime, ';')) == NULL)
687 		return (0);
688 
689 	*mime++ = '\0';
690 	while ((t = strsep(&mime, ";")) != NULL) {
691 		if (!strncmp(t, "charset=", 8)) {
692 			t += 8;
693 			if (!strncasecmp(t, "utf8", 4) ||
694 			    !strncasecmp(t, "utf-8", 5) ||
695 			    !strncasecmp(t, "ascii", 5)) {
696 				log_debug("unknown charset %s", t);
697 				return (-1);
698 			}
699 			continue;
700 		}
701 
702 		if (!strncmp(t, "lang=", 5)) {
703 			t += 5;
704 			if ((semi = strchr(t, ';')) != NULL)
705 				*semi = '\0';
706 
707 			if (strlcpy(lang, t, len) >= len) {
708 				log_debug("lang too long: %s", t);
709 				*lang = '\0';
710 			}
711 
712 			if (semi)
713 				*semi = ';';
714 			continue;
715 		}
716 	}
717 
718 	return (0);
719 }
720 
721 int
722 proxy_start_reply(struct client *clt, int status, const char *ctype)
723 {
724 	const char	*csp;
725 
726 	csp = "Content-Security-Policy: default-src 'self'; "
727 	    "script-src 'none'; object-src 'none';\r\n";
728 
729 	if (status != 200 &&
730 	    clt_printf(clt, "Status: %d\r\n", status) == -1)
731 		return (-1);
732 
733 	if (clt_puts(clt, csp) == -1)
734 		return (-1);
735 
736 	if (status == 302) {
737 		/* use "ctype" as redirect target */
738 		if (clt_printf(clt, "Location: %s\r\n", ctype) == -1)
739 			return (-1);
740 		if (clt_puts(clt, "\r\n") == -1)
741 			return (-1);
742 		return (0);
743 	}
744 
745 	if (ctype != NULL) {
746 		if (!strcmp(ctype, "text/html"))
747 			ctype = "text/html;charset=utf-8";
748 		if (clt_printf(clt, "Content-Type: %s\r\n", ctype)
749 		    == -1)
750 			return (-1);
751 	}
752 
753 	if (clt_puts(clt, "\r\n") == -1)
754 		return (-1);
755 
756 	return (0);
757 }
758 
759 void
760 proxy_read(struct bufferevent *bev, void *d)
761 {
762 	struct client		*clt = d;
763 	struct evbuffer		*src = EVBUFFER_INPUT(bev);
764 	const char		*ctype;
765 	char			 buf[1025];
766 	char			 lang[16];
767 	char			*hdr, *mime;
768 	size_t			 len;
769 	int			 code;
770 
771 	if (clt->clt_headersdone) {
772 		if (clt->clt_translate)
773 			proxy_translate_gemtext(clt);
774 		else
775 			clt_write_bufferevent(clt, bev);
776 		return;
777 	}
778 
779 	hdr = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
780 	if (hdr == NULL) {
781 		if (EVBUFFER_LENGTH(src) >= 1026)
782 			proxy_error(bev, EV_READ, clt);
783 		return;
784 	}
785 
786 	if (len < 4 ||
787 	    !isdigit((unsigned char)hdr[0]) ||
788 	    !isdigit((unsigned char)hdr[1]) ||
789 	    hdr[2] != ' ') {
790 		log_warnx("invalid ");
791 		proxy_error(bev, EV_READ, clt);
792 		goto err;
793 	}
794 
795 	code = (hdr[0] - '0') * 10 + (hdr[1] - '0');
796 
797 	switch (hdr[0]) {
798 	case '1':
799 		if (proxy_start_reply(clt, 200, "text/html") == -1)
800 			goto err;
801 		if (tp_inputpage(clt->clt_tp, &hdr[3]) == -1)
802 			goto err;
803 		fcgi_end_request(clt, 0);
804 		goto err;
805 	case '2':
806 		/* handled below */
807 		break;
808 	case '3':
809 		if (proxy_resurl(clt, &hdr[3], buf, sizeof(buf)) == 0) {
810 			if (proxy_start_reply(clt, 302, buf) == -1)
811 				goto err;
812 			fcgi_end_request(clt, 0);
813 			goto err;
814 		}
815 		/* fallthrough */
816 	default:
817 		if (proxy_start_reply(clt, 501, "text/html") == -1)
818 			goto err;
819 		if (tp_error(clt->clt_tp, code, &hdr[3]) == -1)
820 			goto err;
821 		fcgi_end_request(clt, 1);
822 		goto err;
823 	}
824 
825 	mime = hdr + 2 + strspn(hdr + 2, " \t");
826 	if (parse_mime(clt, mime, lang, sizeof(lang)) == -1) {
827 		if (proxy_start_reply(clt, 501, "text/html") == -1)
828 			goto err;
829 		if (tp_error(clt->clt_tp, -1, "Bad response") == -1)
830 			goto err;
831 		fcgi_end_request(clt, 1);
832 		goto err;
833 	}
834 
835 	if (clt->clt_translate)
836 		ctype = "text/html;charset=utf-8";
837 	else
838 		ctype = mime;
839 
840 	if (clt_printf(clt, "Content-Type: %s\r\n\r\n", ctype) == -1)
841 		goto err;
842 
843 	clt->clt_headersdone = 1;
844 
845 	if (clt->clt_translate &&
846 	    tp_head(clt->clt_tp, lang, NULL) == -1)
847 		goto err;
848 
849 	/*
850 	 * Trigger the read again so we proceed with the response
851 	 * body, if any.
852 	 */
853 	free(hdr);
854 	proxy_read(bev, d);
855 	return;
856 
857 err:
858 	free(hdr);
859 }
860 
861 void
862 proxy_write(struct bufferevent *bev, void *d)
863 {
864 	return;
865 }
866 
867 void
868 proxy_error(struct bufferevent *bev, short err, void *d)
869 {
870 	struct client		*clt = d;
871 	int			 status = !(err & EVBUFFER_EOF);
872 
873 	log_debug("proxy error, shutting down the connection (err: %x)",
874 	    err);
875 
876 	if (!clt->clt_headersdone) {
877 		if (proxy_start_reply(clt, 501, "text/html") == -1)
878 			return;
879 		if (tp_error(clt->clt_tp, -1, "Proxy error") == -1)
880 			return;
881 	} else if (status == 0) {
882 		if (clt->clt_translate & TR_PRE) {
883 			if (tp_pre_close(clt->clt_tp))
884 				return;
885 			clt->clt_translate &= ~TR_PRE;
886 		}
887 
888 		if (clt->clt_translate & TR_LIST) {
889 			if (clt_puts(clt, "</ul>") == -1)
890 				return;
891 			clt->clt_translate &= ~TR_LIST;
892 		}
893 
894 		if (clt->clt_translate & TR_NAV) {
895 			if (clt_puts(clt, "</ul></nav>") == -1)
896 				return;
897 			clt->clt_translate &= ~TR_NAV;
898 		}
899 
900 		if (clt->clt_translate &&
901 		    tp_foot(clt->clt_tp) == -1)
902 			return;
903 	}
904 
905 	fcgi_end_request(clt, status);
906 }
907 
908 void
909 proxy_tls_readcb(int fd, short event, void *arg)
910 {
911 	struct bufferevent	*bufev = arg;
912 	struct client		*clt = bufev->cbarg;
913 	char			 rbuf[IBUF_READ_SIZE];
914 	int			 what = EVBUFFER_READ;
915 	int			 howmuch = IBUF_READ_SIZE;
916 	ssize_t			 ret;
917 	size_t			 len;
918 
919 	if (event == EV_TIMEOUT) {
920 		what |= EVBUFFER_TIMEOUT;
921 		goto err;
922 	}
923 
924 	if (bufev->wm_read.high != 0)
925 		howmuch = MINIMUM(sizeof(rbuf), bufev->wm_read.high);
926 
927 	ret = tls_read(clt->clt_ctx, rbuf, howmuch);
928 	if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) {
929 		goto retry;
930 	} else if (ret == -1) {
931 		what |= EVBUFFER_ERROR;
932 		goto err;
933 	}
934 	len = ret;
935 
936 	if (len == 0) {
937 		what |= EVBUFFER_EOF;
938 		goto err;
939 	}
940 
941 	if (evbuffer_add(bufev->input, rbuf, len) == -1) {
942 		what |= EVBUFFER_ERROR;
943 		goto err;
944 	}
945 
946 	proxy_bufferevent_add(&bufev->ev_read, G_TOUT(bufev->timeout_read));
947 
948 	len = EVBUFFER_LENGTH(bufev->input);
949 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
950 		return;
951 	if (bufev->wm_read.high != 0 && len > bufev->wm_read.high) {
952 		struct evbuffer *buf = bufev->input;
953 		event_del(&bufev->ev_read);
954 		evbuffer_setcb(buf, bufferevent_read_pressure_cb, bufev);
955 		return;
956 	}
957 
958 	if (bufev->readcb != NULL)
959 		(*bufev->readcb)(bufev, bufev->cbarg);
960 	return;
961 
962 retry:
963 	proxy_bufferevent_add(&bufev->ev_read, G_TOUT(bufev->timeout_read));
964 	return;
965 
966 err:
967 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
968 }
969 
970 int
971 proxy_bufferevent_add(struct event *ev, int timeout)
972 {
973 	struct timeval tv, *ptv = NULL;
974 
975 	if (timeout) {
976 		timerclear(&tv);
977 		tv.tv_sec = timeout;
978 		ptv = &tv;
979 	}
980 
981 	return (event_add(ev, ptv));
982 }
983 
984 void
985 proxy_tls_writecb(int fd, short event, void *arg)
986 {
987 	struct bufferevent	*bufev = arg;
988 	struct client		*clt = bufev->cbarg;
989 	ssize_t			 ret;
990 	short			 what = EVBUFFER_WRITE;
991 	size_t			 len;
992 
993 	if (event == EV_TIMEOUT) {
994 		what |= EVBUFFER_TIMEOUT;
995 		goto err;
996 	}
997 
998 	if (EVBUFFER_LENGTH(bufev->output)) {
999 		ret = tls_write(clt->clt_ctx,
1000 		    EVBUFFER_DATA(bufev->output),
1001 		    EVBUFFER_LENGTH(bufev->output));
1002 		if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) {
1003 			goto retry;
1004 		} else if (ret == -1) {
1005 			what |= EVBUFFER_ERROR;
1006 			goto err;
1007 		}
1008 		len = ret;
1009 		evbuffer_drain(bufev->output, len);
1010 	}
1011 
1012 	if (EVBUFFER_LENGTH(bufev->output) != 0)
1013 		proxy_bufferevent_add(&bufev->ev_write,
1014 		    G_TOUT(bufev->timeout_write));
1015 
1016 	if (bufev->writecb != NULL &&
1017 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
1018 		(*bufev->writecb)(bufev, bufev->cbarg);
1019 	return;
1020 
1021 retry:
1022 	proxy_bufferevent_add(&bufev->ev_write, G_TOUT(bufev->timeout_write));
1023 	return;
1024 
1025 err:
1026 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
1027 }
1028 
1029 void
1030 proxy_client_free(struct client *clt)
1031 {
1032 	if (clt->clt_evasr)
1033 		event_asr_abort(clt->clt_evasr);
1034 
1035 	if (clt->clt_addrinfo)
1036 		freeaddrinfo(clt->clt_addrinfo);
1037 
1038 	if (clt->clt_evconn_live)
1039 		event_del(&clt->clt_evconn);
1040 
1041 	if (clt->clt_fd != -1)
1042 		close(clt->clt_fd);
1043 
1044 	if (clt->clt_ctx)
1045 		tls_free(clt->clt_ctx);
1046 
1047 	if (clt->clt_bev)
1048 		bufferevent_free(clt->clt_bev);
1049 
1050 	template_free(clt->clt_tp);
1051 
1052 	free(clt->clt_body);
1053 	free(clt->clt_server_name);
1054 	free(clt->clt_script_name);
1055 	free(clt->clt_path_info);
1056 	free(clt->clt_query);
1057 	free(clt);
1058 }