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Date:: Wed May 25 18:03:07 2022 UTC
Message:: handle mark_nonblock_cloexec failure
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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 #include "utils.h"
41 
42 static struct imsgev		*iev_ui;
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 		if (!mark_nonblock_cloexec(req->fd))
177 			goto err;
178 		if (connect(req->fd, req->p->ai_addr, req->p->ai_addrlen) == 0)
179 			goto done;
180 		yield_w(req, try_to_connect, NULL);
181 	}
182 	return;
183 
184 err:
185 	freeaddrinfo(req->servinfo);
186 	close_with_errf(req, "failed to connect to %s",
187 	    req->url.host);
188 	return;
189 
190 done:
191 	freeaddrinfo(req->servinfo);
192 
193 	switch (req->proto) {
194 	case PROTO_FINGER:
195 	case PROTO_GOPHER:
196 		/* finger and gopher don't have a header nor TLS */
197 		req->done_header = 1;
198 		net_ready(req);
199 		break;
200 
201 	case PROTO_GEMINI: {
202 		struct tls_config *conf;
203 
204 		if ((conf = tls_config_new()) == NULL)
205 			die();
206 
207 		tls_config_insecure_noverifycert(conf);
208 		tls_config_insecure_noverifyname(conf);
209 
210 		/* prepare tls */
211 		if ((req->ctx = tls_client()) == NULL) {
212 			close_with_errf(req, "tls_client: %s",
213 			    strerror(errno));
214 			return;
215 		}
216 
217 		if (tls_configure(req->ctx, conf) == -1) {
218 			close_with_errf(req, "tls_configure: %s",
219 			    tls_error(req->ctx));
220 			return;
221 		}
222 		tls_config_free(conf);
223 
224 		if (tls_connect_socket(req->ctx, req->fd, req->url.host)
225 		    == -1) {
226 			close_with_errf(req, "tls_connect_socket: %s",
227 			    tls_error(req->ctx));
228 			return;
229 		}
230 		yield_w(req, net_tls_handshake, &timeout_for_handshake);
231 		break;
232 	}
233 
234 	default:
235 		die();
236 	}
237 }
238 
239 #if HAVE_ASR_RUN
240 static void
241 query_done(struct asr_result *res, void *d)
242 {
243 	struct req	*req = d;
244 
245 	req->asrev = NULL;
246 	if (res->ar_gai_errno != 0) {
247 		close_with_errf(req, "failed to resolve %s: %s",
248 		    req->url.host, gai_strerror(res->ar_gai_errno));
249 		return;
250 	}
251 
252 	req->fd = -1;
253 	req->servinfo = res->ar_addrinfo;
254 	req->p = res->ar_addrinfo;
255 	try_to_connect(0, 0, req);
256 }
257 
258 static void
259 async_conn_towards(struct req *req)
260 {
261 	struct asr_query	*q;
262 	const char		*proto = "1965";
263 
264 	if (*req->url.port != '\0')
265 		proto = req->url.port;
266 
267 	req->hints.ai_family = AF_UNSPEC;
268 	req->hints.ai_socktype = SOCK_STREAM;
269 	q = getaddrinfo_async(req->url.host, proto, &req->hints, NULL);
270 	req->asrev = event_asr_run(q, query_done, req);
271 }
272 #else
273 static void
274 blocking_conn_towards(struct req *req)
275 {
276 	struct addrinfo	 hints;
277 	struct phos_uri	*url = &req->url;
278 	int		 status;
279 	const char	*proto = "1965";
280 
281 	if (*url->port != '\0')
282 		proto = url->port;
283 
284 	memset(&hints, 0, sizeof(hints));
285 	hints.ai_family = AF_UNSPEC;
286 	hints.ai_socktype = SOCK_STREAM;
287 
288 	if ((status = getaddrinfo(url->host, proto, &hints, &req->servinfo))) {
289 		close_with_errf(req, "failed to resolve %s: %s",
290 		    url->host, gai_strerror(status));
291 		return;
292 	}
293 
294 	req->fd = -1;
295 	req->p = req->servinfo;
296 	try_to_connect(0, 0, req);
297 }
298 #endif
299 
300 static void
301 close_conn(int fd, short ev, void *d)
302 {
303 	struct req	*req = d;
304 
305 #if HAVE_ASR_RUN
306 	if (req->asrev != NULL)
307 		event_asr_abort(req->asrev);
308 #endif
309 
310 	if (req->bev != NULL) {
311 		bufferevent_free(req->bev);
312 		req->bev = NULL;
313 	}
314 
315 	if (req->ctx != NULL) {
316 		switch (tls_close(req->ctx)) {
317 		case TLS_WANT_POLLIN:
318 			yield_r(req, close_conn, NULL);
319 			return;
320 		case TLS_WANT_POLLOUT:
321 			yield_w(req, close_conn, NULL);
322 			return;
323 		}
324 
325 		tls_free(req->ctx);
326 		req->ctx = NULL;
327 	}
328 
329 	TAILQ_REMOVE(&reqhead, req, reqs);
330 	if (req->fd != -1)
331 		close(req->fd);
332 	free(req);
333 }
334 
335 static void
336 close_with_err(struct req *req, const char *err)
337 {
338 	net_send_ui(IMSG_ERR, req->id, err, strlen(err)+1);
339 	close_conn(0, 0, req);
340 }
341 
342 static void
343 close_with_errf(struct req *req, const char *fmt, ...)
344 {
345 	va_list	 ap;
346 	char	*s;
347 
348 	va_start(ap, fmt);
349 	if (vasprintf(&s, fmt, ap) == -1)
350 		abort();
351 	va_end(ap);
352 
353 	close_with_err(req, s);
354 	free(s);
355 }
356 
357 static void
358 net_tls_handshake(int fd, short event, void *d)
359 {
360 	struct req	*req = d;
361 	const char	*hash;
362 
363 	if (event == EV_TIMEOUT) {
364 		close_with_err(req, "Timeout loading page");
365 		return;
366 	}
367 
368 	switch (tls_handshake(req->ctx)) {
369 	case TLS_WANT_POLLIN:
370 		yield_r(req, net_tls_handshake, NULL);
371 		return;
372 	case TLS_WANT_POLLOUT:
373 		yield_w(req, net_tls_handshake, NULL);
374 		return;
375 	}
376 
377 	hash = tls_peer_cert_hash(req->ctx);
378 	if (hash == NULL) {
379 		close_with_errf(req, "handshake failed: %s",
380 		    tls_error(req->ctx));
381 		return;
382 	}
383 	net_send_ui(IMSG_CHECK_CERT, req->id, hash, strlen(hash)+1);
384 }
385 
386 static void
387 net_tls_readcb(int fd, short event, void *d)
388 {
389 	struct bufferevent	*bufev = d;
390 	struct req		*req = bufev->cbarg;
391 	char			 buf[IBUF_READ_SIZE];
392 	int			 what = EVBUFFER_READ;
393 	int			 howmuch = IBUF_READ_SIZE;
394 	int			 res;
395 	ssize_t			 ret;
396 	size_t			 len;
397 
398 	if (event == EV_TIMEOUT) {
399 		what |= EVBUFFER_TIMEOUT;
400 		goto err;
401 	}
402 
403 	if (bufev->wm_read.high != 0)
404 		howmuch = MIN(sizeof(buf), bufev->wm_read.high);
405 
406 	switch (ret = tls_read(req->ctx, buf, howmuch)) {
407 	case TLS_WANT_POLLIN:
408 	case TLS_WANT_POLLOUT:
409 		goto retry;
410 	case -1:
411 		what |= EVBUFFER_ERROR;
412 		goto err;
413 	}
414 	len = ret;
415 
416 	if (len == 0) {
417 		what |= EVBUFFER_EOF;
418 		goto err;
419 	}
420 
421 	res = evbuffer_add(bufev->input, buf, len);
422 	if (res == -1) {
423 		what |= EVBUFFER_ERROR;
424 		goto err;
425 	}
426 
427 	event_add(&bufev->ev_read, NULL);
428 
429 	len = EVBUFFER_LENGTH(bufev->input);
430 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
431 		return;
432 
433 	if (bufev->readcb != NULL)
434 		(*bufev->readcb)(bufev, bufev->cbarg);
435 	return;
436 
437 retry:
438 	event_add(&bufev->ev_read, NULL);
439 	return;
440 
441 err:
442 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
443 }
444 
445 static void
446 net_tls_writecb(int fd, short event, void *d)
447 {
448 	struct bufferevent	*bufev = d;
449 	struct req		*req = bufev->cbarg;
450 	ssize_t			 ret;
451 	size_t			 len;
452 	short			 what = EVBUFFER_WRITE;
453 
454 	if (event & EV_TIMEOUT) {
455 		what |= EVBUFFER_TIMEOUT;
456 		goto err;
457 	}
458 
459 	if (EVBUFFER_LENGTH(bufev->output) != 0) {
460 		ret = tls_write(req->ctx, EVBUFFER_DATA(bufev->output),
461 		    EVBUFFER_LENGTH(bufev->output));
462 		switch (ret) {
463 		case TLS_WANT_POLLIN:
464 		case TLS_WANT_POLLOUT:
465 			goto retry;
466 		case -1:
467 			what |= EVBUFFER_ERROR;
468 			goto err;
469 		}
470 		len = ret;
471 
472 		evbuffer_drain(bufev->output, len);
473 	}
474 
475 	if (EVBUFFER_LENGTH(bufev->output) != 0)
476 		event_add(&bufev->ev_write, NULL);
477 
478 	if (bufev->writecb != NULL &&
479 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
480 		(*bufev->writecb)(bufev, bufev->cbarg);
481 	return;
482 
483 retry:
484 	event_add(&bufev->ev_write, NULL);
485 	return;
486 
487 err:
488 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
489 }
490 
491 static int
492 gemini_parse_reply(struct req *req, const char *header, size_t len)
493 {
494 	int		 code;
495 	const char	*t;
496 
497 	if (len < 4)
498 		return 0;
499 
500 	if (!isdigit(header[0]) || !isdigit(header[1]))
501 		return 0;
502 
503 	code = (header[0] - '0')*10 + (header[1] - '0');
504 	if (header[2] != ' ')
505 		return 0;
506 
507 	t = header + 3;
508 
509 	net_send_ui(IMSG_GOT_CODE, req->id, &code, sizeof(code));
510 	net_send_ui(IMSG_GOT_META, req->id, t, strlen(t)+1);
511 
512 	bufferevent_disable(req->bev, EV_READ|EV_WRITE);
513 
514 	return code;
515 }
516 
517 /* called when we're ready to read/write */
518 static void
519 net_ready(struct req *req)
520 {
521 	req->bev = bufferevent_new(req->fd, net_read, net_write, net_error,
522 	    req);
523 	if (req->bev == NULL)
524 		die();
525 
526 #if HAVE_EVENT2
527 	evbuffer_unfreeze(req->bev->input, 0);
528 	evbuffer_unfreeze(req->bev->output, 1);
529 #endif
530 
531 	/* setup tls i/o layer */
532 	if (req->ctx != NULL) {
533 		event_set(&req->bev->ev_read, req->fd, EV_READ,
534 		    net_tls_readcb, req->bev);
535 		event_set(&req->bev->ev_write, req->fd, EV_WRITE,
536 		    net_tls_writecb, req->bev);
537 	}
538 
539 	/* TODO: adjust watermarks */
540 	bufferevent_setwatermark(req->bev, EV_WRITE, 1, 0);
541 	bufferevent_setwatermark(req->bev, EV_READ,  1, 0);
542 
543 	bufferevent_enable(req->bev, EV_READ|EV_WRITE);
544 
545 	bufferevent_write(req->bev, req->req, req->len);
546 }
547 
548 /* called after a read has been done */
549 static void
550 net_read(struct bufferevent *bev, void *d)
551 {
552 	struct req	*req = d;
553 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
554 	uint8_t		*data;
555 	size_t		 len, chunk;
556 	int		 r;
557 	char		*header;
558 
559 	if (!req->done_header) {
560 		header = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
561 		if (header == NULL && EVBUFFER_LENGTH(src) >= 1024)
562 			goto err;
563 		if (header == NULL)
564 			return;
565 		r = gemini_parse_reply(req, header, len);
566 		free(header);
567 		req->done_header = 1;
568 		if (r == 0)
569 			goto err;
570 		else if (r < 20 || r >= 30)
571 			close_conn(0, 0, req);
572 		return;
573 	}
574 
575 	if ((len = EVBUFFER_LENGTH(src)) == 0)
576 		return;
577 	data = EVBUFFER_DATA(src);
578 
579 	/*
580 	 * Split data into chunks before sending.  imsg can't handle
581 	 * message that are "too big".
582 	 */
583 	while (len != 0) {
584 		chunk = MIN(len, 4096);
585 		net_send_ui(IMSG_BUF, req->id, data, chunk);
586 		data += chunk;
587 		len -= chunk;
588 	}
589 
590 	evbuffer_drain(src, EVBUFFER_LENGTH(src));
591 	return;
592 
593 err:
594 	(*bev->errorcb)(bev, EVBUFFER_READ, bev->cbarg);
595 }
596 
597 /* called after a write has been done */
598 static void
599 net_write(struct bufferevent *bev, void *d)
600 {
601 	struct evbuffer	*dst = EVBUFFER_OUTPUT(bev);
602 
603 	if (EVBUFFER_LENGTH(dst) == 0)
604 		(*bev->errorcb)(bev, EVBUFFER_WRITE, bev->cbarg);
605 }
606 
607 static void
608 net_error(struct bufferevent *bev, short error, void *d)
609 {
610 	struct req	*req = d;
611 	struct evbuffer	*src;
612 
613 	if (error & EVBUFFER_TIMEOUT) {
614 		close_with_err(req, "Timeout loading page");
615 		return;
616 	}
617 
618 	if (error & EVBUFFER_ERROR) {
619 		close_with_err(req, "buffer event error");
620 		return;
621 	}
622 
623 	if (error & EVBUFFER_EOF) {
624 		/* EOF and no header */
625 		if (!req->done_header) {
626 			close_with_err(req, "protocol error");
627 			return;
628 		}
629 
630 		src = EVBUFFER_INPUT(req->bev);
631 		if (EVBUFFER_LENGTH(src) != 0)
632 			net_send_ui(IMSG_BUF, req->id, EVBUFFER_DATA(src),
633 			    EVBUFFER_LENGTH(src));
634 		net_send_ui(IMSG_EOF, req->id, NULL, 0);
635 		close_conn(0, 0, req);
636 		return;
637 	}
638 
639 	if (error & EVBUFFER_WRITE) {
640 		/* finished sending request */
641 		bufferevent_disable(bev, EV_WRITE);
642 		return;
643 	}
644 
645 	if (error & EVBUFFER_READ) {
646 		close_with_err(req, "protocol error");
647 		return;
648 	}
649 
650 	close_with_errf(req, "unknown event error %x", error);
651 }
652 
653 static void
654 handle_get_raw(struct imsg *imsg, size_t datalen)
655 {
656 	struct req	*req;
657 	struct get_req	*r;
658 
659 	r = imsg->data;
660 
661 	if (datalen != sizeof(*r))
662 		die();
663 
664 	if ((req = calloc(1, sizeof(*req))) == NULL)
665 		die();
666 
667 	req->id = imsg->hdr.peerid;
668 	TAILQ_INSERT_HEAD(&reqhead, req, reqs);
669 
670 	strlcpy(req->url.host, r->host, sizeof(req->url.host));
671 	strlcpy(req->url.port, r->port, sizeof(req->url.port));
672 
673 	strlcpy(req->req, r->req, sizeof(req->req));
674 	req->len = strlen(r->req);
675 
676 	req->proto = r->proto;
677 
678 #if HAVE_ASR_RUN
679 	async_conn_towards(req);
680 #else
681 	blocking_conn_towards(req);
682 #endif
683 }
684 
685 static void
686 handle_cert_status(struct imsg *imsg, size_t datalen)
687 {
688 	struct req	*req;
689 	int		 is_ok;
690 
691 	req = req_by_id(imsg->hdr.peerid);
692 
693 	if (datalen < sizeof(is_ok))
694 		die();
695 	memcpy(&is_ok, imsg->data, sizeof(is_ok));
696 
697 	if (is_ok)
698 		net_ready(req);
699 	else
700 		close_conn(0, 0, req);
701 }
702 
703 static void
704 handle_proceed(struct imsg *imsg, size_t datalen)
705 {
706 	struct req *req;
707 
708 	if ((req = req_by_id(imsg->hdr.peerid)) == NULL)
709 		return;
710 
711 	bufferevent_enable(req->bev, EV_READ);
712 }
713 
714 static void
715 handle_stop(struct imsg *imsg, size_t datalen)
716 {
717 	struct req	*req;
718 
719 	if ((req = req_by_id(imsg->hdr.peerid)) == NULL)
720 		return;
721 	close_conn(0, 0, req);
722 }
723 
724 static void
725 handle_quit(struct imsg *imsg, size_t datalen)
726 {
727 	event_loopbreak();
728 }
729 
730 static void
731 handle_dispatch_imsg(int fd, short ev, void *d)
732 {
733 	struct imsgev	*iev = d;
734 
735 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1)
736 		err(1, "connection closed");
737 }
738 
739 static int
740 net_send_ui(int type, uint32_t peerid, const void *data,
741     uint16_t datalen)
742 {
743 	return imsg_compose_event(iev_ui, type, peerid, 0, -1,
744 	    data, datalen);
745 }
746 
747 int
748 net_main(void)
749 {
750 	setproctitle("net");
751 
752 	TAILQ_INIT(&reqhead);
753 
754 	event_init();
755 
756 	/* Setup pipe and event handler to the main process */
757 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
758 		die();
759 	imsg_init(&iev_ui->ibuf, 3);
760 	iev_ui->handler = handle_dispatch_imsg;
761 	iev_ui->events = EV_READ;
762 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
763 	    iev_ui->handler, iev_ui);
764 	event_add(&iev_ui->ev, NULL);
765 
766 	sandbox_net_process();
767 
768 	event_dispatch();
769 
770 	msgbuf_clear(&iev_ui->ibuf.w);
771 	close(iev_ui->ibuf.fd);
772 	free(iev_ui);
773 
774 	return 0;
775 }