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