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Date:: Sun Jul 25 10:01:20 2021 UTC
Message:: support finger:// urls!
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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 "compat.h"
18 
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 
22 #include <netinet/in.h>
23 
24 #include <assert.h>
25 #include <ctype.h>
26 #include <errno.h>
27 #include <netdb.h>
28 #include <stdarg.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <tls.h>
33 #include <unistd.h>
34 
35 #if HAVE_ASR_RUN
36 # include <asr.h>
37 #endif
38 
39 #include "telescope.h"
40 
41 static struct imsgev		*iev_ui;
42 static struct tls_config	*tlsconf;
43 
44 /* a pending request */
45 struct req {
46 	struct phos_uri		 url;
47 	uint32_t		 id;
48 	int			 proto;
49 	int			 fd;
50 	struct tls		*ctx;
51 	char			 req[1024];
52 	size_t			 len;
53 	int			 done_header;
54 	struct bufferevent	*bev;
55 
56 	struct addrinfo		*servinfo, *p;
57 #if HAVE_ASR_RUN
58 	struct addrinfo		 hints;
59 	struct event_asr	*asrev;
60 #endif
61 
62 	TAILQ_ENTRY(req)	 reqs;
63 };
64 
65 static struct req	*req_by_id(uint32_t);
66 
67 static void	 die(void) __attribute__((__noreturn__));
68 
69 static void	 try_to_connect(int, short, void*);
70 
71 #if HAVE_ASR_RUN
72 static void	 query_done(struct asr_result*, void*);
73 static void	 async_conn_towards(struct req*);
74 #else
75 static void	 blocking_conn_towards(struct req*);
76 #endif
77 
78 static void	 close_with_err(struct req*, const char*);
79 static void	 close_with_errf(struct req*, const char*, ...)
80     __attribute__((format(printf, 2, 3)));
81 
82 static void	 net_tls_handshake(int, short, void *);
83 static void	 net_tls_readcb(int, short, void *);
84 static void	 net_tls_writecb(int, short, void *);
85 
86 static int	 gemini_parse_reply(struct req *, const char *, size_t);
87 
88 static void	 net_ready(struct req *req);
89 static void	 net_read(struct bufferevent *, void *);
90 static void	 net_write(struct bufferevent *, void *);
91 static void	 net_error(struct bufferevent *, short, void *);
92 
93 static void	 handle_get_raw(struct imsg *, size_t);
94 static void	 handle_cert_status(struct imsg*, size_t);
95 static void	 handle_proceed(struct imsg*, size_t);
96 static void	 handle_stop(struct imsg*, size_t);
97 static void	 handle_quit(struct imsg*, size_t);
98 static void	 handle_dispatch_imsg(int, short, void*);
99 
100 static int	 net_send_ui(int, uint32_t, const void *, uint16_t);
101 
102 /* TODO: making this customizable */
103 struct timeval timeout_for_handshake = { 5, 0 };
104 
105 static imsg_handlerfn *handlers[] = {
106 	[IMSG_GET_RAW]		= handle_get_raw,
107 	[IMSG_CERT_STATUS]	= handle_cert_status,
108 	[IMSG_PROCEED]		= handle_proceed,
109 	[IMSG_STOP]		= handle_stop,
110 	[IMSG_QUIT]		= handle_quit,
111 };
112 
113 typedef void (*statefn)(int, short, void*);
114 
115 TAILQ_HEAD(, req) reqhead;
116 
117 static inline void
118 yield_r(struct req *req, statefn fn, struct timeval *tv)
119 {
120 	event_once(req->fd, EV_READ, fn, req, tv);
121 }
122 
123 static inline void
124 yield_w(struct req *req, statefn fn, struct timeval *tv)
125 {
126 	event_once(req->fd, EV_WRITE, fn, req, tv);
127 }
128 
129 static struct req *
130 req_by_id(uint32_t id)
131 {
132 	struct req *r;
133 
134 	TAILQ_FOREACH(r, &reqhead, reqs) {
135 		if (r->id == id)
136 			return r;
137 	}
138 
139 	return NULL;
140 }
141 
142 static void __attribute__((__noreturn__))
143 die(void)
144 {
145 	abort(); 		/* TODO */
146 }
147 
148 static void
149 try_to_connect(int fd, short ev, void *d)
150 {
151 	struct req	*req = d;
152 	int		 error = 0;
153 	socklen_t	 len = sizeof(error);
154 
155 again:
156 	if (req->p == NULL)
157 		goto err;
158 
159 	if (req->fd != -1) {
160 		if (getsockopt(req->fd, SOL_SOCKET, SO_ERROR, &error,
161 		    &len) == -1)
162 			goto err;
163 		if (error != 0) {
164                         errno = error;
165                         goto err;
166 		}
167 		goto done;
168 	}
169 
170 	req->fd = socket(req->p->ai_family, req->p->ai_socktype,
171 	    req->p->ai_protocol);
172 	if (req->fd == -1) {
173 		req->p = req->p->ai_next;
174 		goto again;
175 	} else {
176 		mark_nonblock(req->fd);
177 		if (connect(req->fd, req->p->ai_addr, req->p->ai_addrlen) == 0)
178 			goto done;
179 		yield_w(req, try_to_connect, NULL);
180 	}
181 	return;
182 
183 err:
184 	freeaddrinfo(req->servinfo);
185 	close_with_errf(req, "failed to connect to %s",
186 	    req->url.host);
187 	return;
188 
189 done:
190 	freeaddrinfo(req->servinfo);
191 
192 	switch (req->proto) {
193 	case PROTO_FINGER:
194 		/* finger doesn't have a header */
195 		req->done_header = 1;
196 		net_ready(req);
197 		break;
198 
199 	case PROTO_GEMINI:
200 		/* prepare tls */
201 		if ((req->ctx = tls_client()) == NULL) {
202 			close_with_errf(req, "tls_client: %s",
203 			    strerror(errno));
204 			return;
205 		}
206 		if (tls_configure(req->ctx, tlsconf) == -1) {
207 			close_with_errf(req, "tls_configure: %s",
208 			    tls_error(req->ctx));
209 			return;
210 		}
211 		if (tls_connect_socket(req->ctx, req->fd, req->url.host)
212 		    == -1) {
213 			close_with_errf(req, "tls_connect_socket: %s",
214 			    tls_error(req->ctx));
215 			return;
216 		}
217 		yield_w(req, net_tls_handshake, &timeout_for_handshake);
218 		break;
219 
220 	default:
221 		die();
222 	}
223 }
224 
225 #if HAVE_ASR_RUN
226 static void
227 query_done(struct asr_result *res, void *d)
228 {
229 	struct req	*req = d;
230 
231 	req->asrev = NULL;
232 	if (res->ar_gai_errno != 0) {
233 		close_with_errf(req, "failed to resolve %s: %s",
234 		    req->url.host, gai_strerror(res->ar_gai_errno));
235 		return;
236 	}
237 
238 	req->fd = -1;
239 	req->servinfo = res->ar_addrinfo;
240 	req->p = res->ar_addrinfo;
241 	try_to_connect(0, 0, req);
242 }
243 
244 static void
245 async_conn_towards(struct req *req)
246 {
247 	struct asr_query	*q;
248 	const char		*proto = "1965";
249 
250 	if (*req->url.port != '\0')
251 		proto = req->url.port;
252 
253 	req->hints.ai_family = AF_UNSPEC;
254 	req->hints.ai_socktype = SOCK_STREAM;
255 	q = getaddrinfo_async(req->url.host, proto, &req->hints, NULL);
256 	req->asrev = event_asr_run(q, query_done, req);
257 }
258 #else
259 static void
260 blocking_conn_towards(struct req *req)
261 {
262 	struct addrinfo	 hints;
263 	struct phos_uri	*url = &req->url;
264 	int		 status;
265 	const char	*proto = "1965";
266 
267 	if (*url->port != '\0')
268 		proto = url->port;
269 
270 	memset(&hints, 0, sizeof(hints));
271 	hints.ai_family = AF_UNSPEC;
272 	hints.ai_socktype = SOCK_STREAM;
273 
274 	if ((status = getaddrinfo(url->host, proto, &hints, &req->servinfo))) {
275 		close_with_errf(req, "failed to resolve %s: %s",
276 		    url->host, gai_strerror(status));
277 		return;
278 	}
279 
280 	req->fd = -1;
281 	req->p = req->servinfo;
282 	try_to_connect(0, 0, req);
283 }
284 #endif
285 
286 static void
287 close_conn(int fd, short ev, void *d)
288 {
289 	struct req	*req = d;
290 
291 #if HAVE_ASR_RUN
292 	if (req->asrev != NULL)
293 		event_asr_abort(req->asrev);
294 #endif
295 
296 	if (req->bev != NULL) {
297 		bufferevent_free(req->bev);
298 		req->bev = NULL;
299 	}
300 
301 	if (req->ctx != NULL) {
302 		switch (tls_close(req->ctx)) {
303 		case TLS_WANT_POLLIN:
304 			yield_r(req, close_conn, NULL);
305 			return;
306 		case TLS_WANT_POLLOUT:
307 			yield_w(req, close_conn, NULL);
308 			return;
309 		}
310 
311 		tls_free(req->ctx);
312 		req->ctx = NULL;
313 	}
314 
315 	TAILQ_REMOVE(&reqhead, req, reqs);
316 	if (req->fd != -1)
317 		close(req->fd);
318 	free(req);
319 }
320 
321 static void
322 close_with_err(struct req *req, const char *err)
323 {
324 	net_send_ui(IMSG_ERR, req->id, err, strlen(err)+1);
325 	close_conn(0, 0, req);
326 }
327 
328 static void
329 close_with_errf(struct req *req, const char *fmt, ...)
330 {
331 	va_list	 ap;
332 	char	*s;
333 
334 	va_start(ap, fmt);
335 	if (vasprintf(&s, fmt, ap) == -1)
336 		abort();
337 	va_end(ap);
338 
339 	close_with_err(req, s);
340 	free(s);
341 }
342 
343 static void
344 net_tls_handshake(int fd, short event, void *d)
345 {
346 	struct req	*req = d;
347 	const char	*hash;
348 
349 	if (event == EV_TIMEOUT) {
350 		close_with_err(req, "Timeout loading page");
351 		return;
352 	}
353 
354 	switch (tls_handshake(req->ctx)) {
355 	case TLS_WANT_POLLIN:
356 		yield_r(req, net_tls_handshake, NULL);
357 		return;
358 	case TLS_WANT_POLLOUT:
359 		yield_w(req, net_tls_handshake, NULL);
360 		return;
361 	}
362 
363 	hash = tls_peer_cert_hash(req->ctx);
364 	if (hash == NULL) {
365 		close_with_errf(req, "handshake failed: %s",
366 		    tls_error(req->ctx));
367 		return;
368 	}
369 	net_send_ui(IMSG_CHECK_CERT, req->id, hash, strlen(hash)+1);
370 }
371 
372 static void
373 net_tls_readcb(int fd, short event, void *d)
374 {
375 	struct bufferevent	*bufev = d;
376 	struct req		*req = bufev->cbarg;
377 	char			 buf[IBUF_READ_SIZE];
378 	int			 what = EVBUFFER_READ;
379 	int			 howmuch = IBUF_READ_SIZE;
380 	ssize_t			 ret;
381 	size_t			 len;
382 
383 	if (event == EV_TIMEOUT) {
384 		what |= EVBUFFER_TIMEOUT;
385 		goto err;
386 	}
387 
388 	if (bufev->wm_read.high != 0)
389 		howmuch = MIN(sizeof(buf), bufev->wm_read.high);
390 
391 	switch (ret = tls_read(req->ctx, buf, howmuch)) {
392 	case TLS_WANT_POLLIN:
393 	case TLS_WANT_POLLOUT:
394 		goto retry;
395 	case -1:
396 		what |= EVBUFFER_ERROR;
397 		goto err;
398 	}
399 	len = ret;
400 
401 	if (len == 0) {
402 		what |= EVBUFFER_EOF;
403 		goto err;
404 	}
405 
406 	if (evbuffer_add(bufev->input, buf, len) == -1) {
407 		what |= EVBUFFER_ERROR;
408 		goto err;
409 	}
410 
411 	event_add(&bufev->ev_read, NULL);
412 
413 	len = EVBUFFER_LENGTH(bufev->input);
414 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
415 		return;
416 
417 	if (bufev->readcb != NULL)
418 		(*bufev->readcb)(bufev, bufev->cbarg);
419 	return;
420 
421 retry:
422 	event_add(&bufev->ev_read, NULL);
423 	return;
424 
425 err:
426 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
427 }
428 
429 static void
430 net_tls_writecb(int fd, short event, void *d)
431 {
432 	struct bufferevent	*bufev = d;
433 	struct req		*req = bufev->cbarg;
434 	ssize_t			 ret;
435 	size_t			 len;
436 	short			 what = EVBUFFER_WRITE;
437 
438 	if (event & EV_TIMEOUT) {
439 		what |= EVBUFFER_TIMEOUT;
440 		goto err;
441 	}
442 
443 	if (EVBUFFER_LENGTH(bufev->output) != 0) {
444 		ret = tls_write(req->ctx, EVBUFFER_DATA(bufev->output),
445 		    EVBUFFER_LENGTH(bufev->output));
446 		switch (ret) {
447 		case TLS_WANT_POLLIN:
448 		case TLS_WANT_POLLOUT:
449 			goto retry;
450 		case -1:
451 			what |= EVBUFFER_ERROR;
452 			goto err;
453 		}
454 		len = ret;
455 		evbuffer_drain(bufev->output, len);
456 	}
457 
458 	if (EVBUFFER_LENGTH(bufev->output) != 0)
459 		event_add(&bufev->ev_write, NULL);
460 
461 	if (bufev->writecb != NULL &&
462 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
463 		(*bufev->writecb)(bufev, bufev->cbarg);
464 	return;
465 
466 retry:
467 	event_add(&bufev->ev_write, NULL);
468 	return;
469 
470 err:
471 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
472 }
473 
474 static int
475 gemini_parse_reply(struct req *req, const char *header, size_t len)
476 {
477 	int		 code;
478 	const char	*t;
479 
480 	if (len < 4)
481 		return 0;
482 
483 	if (!isdigit(header[0]) || !isdigit(header[1]))
484 		return 0;
485 
486 	code = (header[0] - '0')*10 + (header[1] - '0');
487 	if (header[2] != ' ')
488 		return 0;
489 
490 	t = header + 3;
491 
492 	net_send_ui(IMSG_GOT_CODE, req->id, &code, sizeof(code));
493 	net_send_ui(IMSG_GOT_META, req->id, t, strlen(t)+1);
494 
495 	bufferevent_disable(req->bev, EV_READ|EV_WRITE);
496 
497 	if (code < 20 || code >= 30)
498 		close_conn(0, 0, req);
499 	return 1;
500 }
501 
502 /* called when we're ready to read/write */
503 static void
504 net_ready(struct req *req)
505 {
506 	req->bev = bufferevent_new(req->fd, net_read, net_write, net_error,
507 	    req);
508 	if (req->bev == NULL)
509 		die();
510 
511 	/* setup tls i/o layer */
512 	if (req->ctx != NULL) {
513 		event_set(&req->bev->ev_read, req->fd, EV_READ,
514 		    net_tls_readcb, req->bev);
515 		event_set(&req->bev->ev_write, req->fd, EV_WRITE,
516 		    net_tls_writecb, req->bev);
517 	}
518 
519 	/* TODO: adjust watermarks */
520 	bufferevent_setwatermark(req->bev, EV_WRITE, 1, 0);
521 	bufferevent_setwatermark(req->bev, EV_READ,  1, 0);
522 
523 	bufferevent_enable(req->bev, EV_READ|EV_WRITE);
524 
525 	bufferevent_write(req->bev, req->req, req->len);
526 }
527 
528 /* called after a read has been done */
529 static void
530 net_read(struct bufferevent *bev, void *d)
531 {
532 	struct req	*req = d;
533 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
534 	void		*data;
535 	size_t		 len;
536 	int		 r;
537 	char		*header;
538 
539 	if (!req->done_header) {
540 		header = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
541 		if (header == NULL && EVBUFFER_LENGTH(src) >= 1024)
542 			goto err;
543 		if (header == NULL)
544 			return;
545 		r = gemini_parse_reply(req, header, len);
546 		free(header);
547 		if (!r)
548 			goto err;
549 		req->done_header = 1;
550 		return;
551 	}
552 
553 	if ((len = EVBUFFER_LENGTH(src)) == 0)
554 		return;
555 	data = EVBUFFER_DATA(src);
556 	net_send_ui(IMSG_BUF, req->id, data, len);
557 	evbuffer_drain(src, len);
558 	return;
559 
560 err:
561 	(*bev->errorcb)(bev, EVBUFFER_READ, bev->cbarg);
562 }
563 
564 /* called after a write has been done */
565 static void
566 net_write(struct bufferevent *bev, void *d)
567 {
568 	struct evbuffer	*dst = EVBUFFER_OUTPUT(bev);
569 
570 	if (EVBUFFER_LENGTH(dst) == 0)
571 		(*bev->errorcb)(bev, EVBUFFER_WRITE, bev->cbarg);
572 }
573 
574 static void
575 net_error(struct bufferevent *bev, short error, void *d)
576 {
577 	struct req	*req = d;
578 
579 	if (error & EVBUFFER_TIMEOUT) {
580 		close_with_err(req, "Timeout loading page");
581 		return;
582 	}
583 
584 	if (error & EVBUFFER_ERROR) {
585 		close_with_err(req, "buffer event error");
586 		return;
587 	}
588 
589 	if (error & EVBUFFER_EOF) {
590 		net_send_ui(IMSG_EOF, req->id, NULL, 0);
591 		close_conn(0, 0, req);
592 		return;
593 	}
594 
595 	if (error & EVBUFFER_WRITE) {
596 		/* finished sending request */
597 		bufferevent_disable(bev, EV_WRITE);
598 		return;
599 	}
600 
601 	if (error & EVBUFFER_READ) {
602 		close_with_err(req, "protocol error");
603 		return;
604 	}
605 
606 	close_with_errf(req, "unknown event error %x", error);
607 }
608 
609 static void
610 handle_get_raw(struct imsg *imsg, size_t datalen)
611 {
612 	struct req	*req;
613 	struct get_req	*r;
614 
615 	r = imsg->data;
616 
617 	if (datalen != sizeof(*r))
618 		die();
619 
620 	if ((req = calloc(1, sizeof(*req))) == NULL)
621 		die();
622 
623 	req->id = imsg->hdr.peerid;
624 	TAILQ_INSERT_HEAD(&reqhead, req, reqs);
625 
626 	strlcpy(req->url.host, r->host, sizeof(req->url.host));
627 	strlcpy(req->url.port, r->port, sizeof(req->url.port));
628 
629 	strlcpy(req->req, r->req, sizeof(req->req));
630 	req->len = strlen(r->req);
631 
632 	req->proto = r->proto;
633 
634 #if HAVE_ASR_RUN
635         async_conn_towards(req);
636 #else
637 	blocking_conn_towards(req);
638 #endif
639 }
640 
641 static void
642 handle_cert_status(struct imsg *imsg, size_t datalen)
643 {
644 	struct req	*req;
645 	int		 is_ok;
646 
647 	req = req_by_id(imsg->hdr.peerid);
648 
649 	if (datalen < sizeof(is_ok))
650 		die();
651 	memcpy(&is_ok, imsg->data, sizeof(is_ok));
652 
653 	if (is_ok)
654 		net_ready(req);
655 	else
656 		close_conn(0, 0, req);
657 }
658 
659 static void
660 handle_proceed(struct imsg *imsg, size_t datalen)
661 {
662 	struct req *req;
663 
664 	if ((req = req_by_id(imsg->hdr.peerid)) == NULL)
665 		return;
666 
667 	bufferevent_enable(req->bev, EV_READ);
668 }
669 
670 static void
671 handle_stop(struct imsg *imsg, size_t datalen)
672 {
673 	struct req	*req;
674 
675 	if ((req = req_by_id(imsg->hdr.peerid)) == NULL)
676 		return;
677 	close_conn(0, 0, req);
678 }
679 
680 static void
681 handle_quit(struct imsg *imsg, size_t datalen)
682 {
683 	event_loopbreak();
684 }
685 
686 static void
687 handle_dispatch_imsg(int fd, short ev, void *d)
688 {
689 	struct imsgev	*iev = d;
690 
691 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1)
692 		err(1, "connection closed");
693 }
694 
695 static int
696 net_send_ui(int type, uint32_t peerid, const void *data,
697     uint16_t datalen)
698 {
699 	return imsg_compose_event(iev_ui, type, peerid, 0, -1,
700 	    data, datalen);
701 }
702 
703 int
704 net_main(void)
705 {
706 	setproctitle("net");
707 
708 	TAILQ_INIT(&reqhead);
709 
710 	if ((tlsconf = tls_config_new()) == NULL)
711 		die();
712 	tls_config_insecure_noverifycert(tlsconf);
713 	tls_config_insecure_noverifyname(tlsconf);
714 
715 	event_init();
716 
717 	/* Setup pipe and event handler to the main process */
718 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
719 		die();
720 	imsg_init(&iev_ui->ibuf, 3);
721 	iev_ui->handler = handle_dispatch_imsg;
722 	iev_ui->events = EV_READ;
723 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
724 	    iev_ui->handler, iev_ui);
725 	event_add(&iev_ui->ev, NULL);
726 
727 	sandbox_net_process();
728 
729 	event_dispatch();
730 
731 	tls_config_free(tlsconf);
732 	msgbuf_clear(&iev_ui->ibuf.w);
733 	close(iev_ui->ibuf.fd);
734 	free(iev_ui);
735 
736 	return 0;
737 }