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Date:: Wed Jul 21 14:35:24 2021 UTC
Message:: always include compat.h first
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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 static void		 do_handshake(int, short, void*);
64 static void		 write_request(int, short, void*);
65 static void		 read_reply(int, short, void*);
66 static void		 parse_reply(struct req*);
67 static void		 copy_body(int, short, void*);
68 
69 static void		 handle_get_raw(struct imsg *, size_t);
70 static void		 handle_cert_status(struct imsg*, size_t);
71 static void		 handle_proceed(struct imsg*, size_t);
72 static void		 handle_stop(struct imsg*, size_t);
73 static void		 handle_quit(struct imsg*, size_t);
74 static void		 handle_dispatch_imsg(int, short, void*);
75 
76 static int		 net_send_ui(int, uint32_t, const void *, uint16_t);
77 
78 /* TODO: making this customizable */
79 struct timeval timeout_for_handshake = { 5, 0 };
80 
81 static imsg_handlerfn *handlers[] = {
82 	[IMSG_GET_RAW]		= handle_get_raw,
83 	[IMSG_CERT_STATUS]	= handle_cert_status,
84 	[IMSG_PROCEED]		= handle_proceed,
85 	[IMSG_STOP]		= handle_stop,
86 	[IMSG_QUIT]		= handle_quit,
87 };
88 
89 typedef void (*statefn)(int, short, void*);
90 
91 TAILQ_HEAD(, req) reqhead;
92 /* a pending request */
93 struct req {
94 	struct event		 ev;
95 	struct phos_uri		 url;
96 	uint32_t		 id;
97 	int			 fd;
98 	struct tls		*ctx;
99 	char			 buf[1024];
100 	size_t			 off;
101 
102 	struct addrinfo		*servinfo, *p;
103 #if HAVE_ASR_RUN
104 	struct addrinfo		 hints;
105 	struct event_asr	*asrev;
106 #endif
107 
108 	TAILQ_ENTRY(req)	 reqs;
109 };
110 
111 static inline void
112 yield_r(struct req *req, statefn fn, struct timeval *tv)
113 {
114 	event_once(req->fd, EV_READ, fn, req, tv);
115 }
116 
117 static inline void
118 yield_w(struct req *req, statefn fn, struct timeval *tv)
119 {
120 	event_once(req->fd, EV_WRITE, fn, req, tv);
121 }
122 
123 static inline void
124 advance_buf(struct req *req, size_t len)
125 {
126 	assert(len <= req->off);
127 
128 	req->off -= len;
129 	memmove(req->buf, req->buf + len, req->off);
130 }
131 
132 static void __attribute__((__noreturn__))
133 die(void)
134 {
135 	abort(); 		/* TODO */
136 }
137 
138 static void
139 try_to_connect(int fd, short ev, void *d)
140 {
141 	struct req	*req = d;
142 	int		 error = 0;
143 	socklen_t	 len = sizeof(error);
144 
145 again:
146 	if (req->p == NULL)
147 		goto err;
148 
149 	if (req->fd != -1) {
150 		if (getsockopt(req->fd, SOL_SOCKET, SO_ERROR, &error, &len) == -1)
151 			goto err;
152 		if (error != 0) {
153                         errno = error;
154                         goto err;
155 		}
156 		goto done;
157 	}
158 
159 	req->fd = socket(req->p->ai_family, req->p->ai_socktype, req->p->ai_protocol);
160 	if (req->fd == -1) {
161 		req->p = req->p->ai_next;
162 		goto again;
163 	} else {
164 		mark_nonblock(req->fd);
165 		if (connect(req->fd, req->p->ai_addr, req->p->ai_addrlen) == 0)
166 			goto done;
167 		yield_w(req, try_to_connect, NULL);
168 	}
169 	return;
170 
171 err:
172 	freeaddrinfo(req->servinfo);
173 	close_with_errf(req, "failed to connect to %s",
174 	    req->url.host);
175 	return;
176 
177 done:
178 	freeaddrinfo(req->servinfo);
179 	setup_tls(req);
180 }
181 
182 #if HAVE_ASR_RUN
183 static void
184 query_done(struct asr_result *res, void *d)
185 {
186 	struct req	*req = d;
187 
188 	req->asrev = NULL;
189 	if (res->ar_gai_errno != 0) {
190 		close_with_errf(req, "failed to resolve %s: %s",
191 		    req->url.host, gai_strerror(res->ar_gai_errno));
192 		return;
193 	}
194 
195 	req->fd = -1;
196 	req->servinfo = res->ar_addrinfo;
197 	req->p = res->ar_addrinfo;
198 	try_to_connect(0, 0, req);
199 }
200 
201 static void
202 async_conn_towards(struct req *req)
203 {
204 	struct asr_query	*q;
205 	const char		*proto = "1965";
206 
207 	if (*req->url.port != '\0')
208 		proto = req->url.port;
209 
210 	req->hints.ai_family = AF_UNSPEC;
211 	req->hints.ai_socktype = SOCK_STREAM;
212 	q = getaddrinfo_async(req->url.host, proto, &req->hints, NULL);
213 	req->asrev = event_asr_run(q, query_done, req);
214 }
215 #else
216 static void
217 blocking_conn_towards(struct req *req)
218 {
219 	struct addrinfo	 hints;
220 	struct phos_uri	*url = &req->url;
221 	int		 status;
222 	const char	*proto = "1965";
223 
224 	if (*url->port != '\0')
225 		proto = url->port;
226 
227 	memset(&hints, 0, sizeof(hints));
228 	hints.ai_family = AF_UNSPEC;
229 	hints.ai_socktype = SOCK_STREAM;
230 
231 	if ((status = getaddrinfo(url->host, proto, &hints, &req->servinfo))) {
232 		close_with_errf(req, "failed to resolve %s: %s",
233 		    url->host, gai_strerror(status));
234 		return;
235 	}
236 
237 	req->fd = -1;
238 	req->p = req->servinfo;
239 	try_to_connect(0, 0, req);
240 }
241 #endif
242 
243 static struct req *
244 req_by_id(uint32_t id)
245 {
246 	struct req *r;
247 
248 	if ((r = req_by_id_try(id)) == NULL)
249 		die();
250 	return r;
251 }
252 
253 static struct req *
254 req_by_id_try(uint32_t id)
255 {
256 	struct req *r;
257 
258 	TAILQ_FOREACH(r, &reqhead, reqs) {
259 		if (r->id == id)
260 			return r;
261 	}
262 
263 	return NULL;
264 }
265 
266 static void
267 close_conn(int fd, short ev, void *d)
268 {
269 	struct req	*req = d;
270 
271 #if HAVE_ASR_RUN
272 	if (req->asrev != NULL)
273 		event_asr_abort(req->asrev);
274 #endif
275 
276 	if (req->ctx != NULL) {
277 		switch (tls_close(req->ctx)) {
278 		case TLS_WANT_POLLIN:
279 			yield_r(req, close_conn, NULL);
280 			return;
281 		case TLS_WANT_POLLOUT:
282 			yield_w(req, close_conn, NULL);
283 			return;
284 		}
285 
286 		tls_free(req->ctx);
287 	}
288 
289 	TAILQ_REMOVE(&reqhead, req, reqs);
290 	if (req->fd != -1)
291 		close(req->fd);
292 	free(req);
293 }
294 
295 static void
296 close_with_err(struct req *req, const char *err)
297 {
298 	net_send_ui(IMSG_ERR, req->id, err, strlen(err)+1);
299 	close_conn(0, 0, req);
300 }
301 
302 static void
303 close_with_errf(struct req *req, const char *fmt, ...)
304 {
305 	va_list	 ap;
306 	char	*s;
307 
308 	va_start(ap, fmt);
309 	if (vasprintf(&s, fmt, ap) == -1)
310 		abort();
311 	va_end(ap);
312 
313 	close_with_err(req, s);
314 	free(s);
315 }
316 
317 static void
318 setup_tls(struct req *req)
319 {
320 	if ((req->ctx = tls_client()) == NULL) {
321 		close_with_errf(req, "tls_client: %s", strerror(errno));
322 		return;
323 	}
324 	if (tls_configure(req->ctx, tlsconf) == -1) {
325 		close_with_errf(req, "tls_configure: %s", tls_error(req->ctx));
326 		return;
327 	}
328 	if (tls_connect_socket(req->ctx, req->fd, req->url.host) == -1) {
329 		close_with_errf(req, "tls_connect_socket: %s", tls_error(req->ctx));
330 		return;
331 	}
332 	yield_w(req, do_handshake, &timeout_for_handshake);
333 }
334 
335 static void
336 do_handshake(int fd, short ev, void *d)
337 {
338 	struct req	*req = d;
339 	const char	*hash;
340 
341 	if (ev == EV_TIMEOUT) {
342 		close_with_err(req, "Timeout loading page");
343 		return;
344 	}
345 
346 	switch (tls_handshake(req->ctx)) {
347 	case TLS_WANT_POLLIN:
348 		yield_r(req, do_handshake, NULL);
349 		return;
350 	case TLS_WANT_POLLOUT:
351 		yield_w(req, do_handshake, NULL);
352 		return;
353 	}
354 
355 	hash = tls_peer_cert_hash(req->ctx);
356 	if (hash == NULL) {
357 		close_with_errf(req, "handshake failed: %s", tls_error(req->ctx));
358 		return;
359 	}
360 	net_send_ui(IMSG_CHECK_CERT, req->id, hash, strlen(hash)+1);
361 }
362 
363 static void
364 write_request(int fd, short ev, void *d)
365 {
366 	struct req	*req = d;
367 	ssize_t		 r;
368 	size_t		 len;
369 
370 	len = strlen(req->buf);
371 
372 	switch (r = tls_write(req->ctx, req->buf, len)) {
373 	case -1:
374 		close_with_errf(req, "tls_write: %s", tls_error(req->ctx));
375 		break;
376 	case TLS_WANT_POLLIN:
377 		yield_r(req, write_request, NULL);
378 		break;
379 	case TLS_WANT_POLLOUT:
380 		yield_w(req, write_request, NULL);
381 		break;
382 	default:
383 		/* assume r == len */
384 		(void)r;
385 		yield_r(req, read_reply, NULL);
386 		break;
387 	}
388 }
389 
390 static void
391 read_reply(int fd, short ev, void *d)
392 {
393 	struct req	*req = d;
394 	size_t		 len;
395 	ssize_t		 r;
396 	char		*buf;
397 
398 	buf = req->buf + req->off;
399 	len = sizeof(req->buf) - req->off;
400 
401 	switch (r = tls_read(req->ctx, buf, len)) {
402 	case -1:
403 		close_with_errf(req, "tls_read: %s", tls_error(req->ctx));
404 		break;
405 	case TLS_WANT_POLLIN:
406 		yield_r(req, read_reply, NULL);
407 		break;
408 	case TLS_WANT_POLLOUT:
409 		yield_w(req, read_reply, NULL);
410 		break;
411 	default:
412 		req->off += r;
413 
414 		if (memmem(req->buf, req->off, "\r\n", 2) != NULL)
415 			parse_reply(req);
416 		else if (req->off == sizeof(req->buf))
417 			close_with_err(req, "invalid response");
418 		else
419 			yield_r(req, read_reply, NULL);
420 		break;
421 	}
422 }
423 
424 static void
425 parse_reply(struct req *req)
426 {
427 	int	 code;
428 	char	*e;
429 	size_t	 len;
430 
431 	if (req->off < 4)
432 		goto err;
433 
434 	if (!isdigit(req->buf[0]) || !isdigit(req->buf[1]))
435 		goto err;
436 
437 	code = (req->buf[0] - '0')*10 + (req->buf[1] - '0');
438 
439 	if (!isspace(req->buf[2]))
440 		goto err;
441 
442 	advance_buf(req, 3);
443 	if ((e = memmem(req->buf, req->off, "\r\n", 2)) == NULL)
444 		goto err;
445 
446 	*e = '\0';
447 	e++;
448 	len = e - req->buf;
449 	net_send_ui(IMSG_GOT_CODE, req->id, &code, sizeof(code));
450 	net_send_ui(IMSG_GOT_META, req->id, req->buf, len);
451 
452 	if (20 <= code && code < 30)
453 		advance_buf(req, len+1); /* skip \n too */
454 	else
455 		close_conn(0, 0, req);
456 
457 	return;
458 
459 err:
460 	close_with_err(req, "malformed request");
461 }
462 
463 static void
464 copy_body(int fd, short ev, void *d)
465 {
466 	struct req	*req = d;
467 	ssize_t		 r;
468 
469 	for (;;) {
470 		if (req->off != 0) {
471 			net_send_ui(IMSG_BUF, req->id,
472 			    req->buf, req->off);
473 			req->off = 0;
474 		}
475 
476 		switch (r = tls_read(req->ctx, req->buf, sizeof(req->buf))) {
477 		case TLS_WANT_POLLIN:
478 			yield_r(req, copy_body, NULL);
479 			return;
480 		case TLS_WANT_POLLOUT:
481 			yield_w(req, copy_body, NULL);
482 			return;
483 		case -1:
484 			/*
485 			 * XXX: should notify the user that the
486 			 * download was aborted.
487 			 */
488 			/* fallthrough */
489 		case 0:
490 			net_send_ui(IMSG_EOF, req->id, NULL, 0);
491 			close_conn(0, 0, req);
492 			return;
493 		default:
494 			req->off = r;
495 		}
496 	}
497 }
498 
499 static void
500 handle_get_raw(struct imsg *imsg, size_t datalen)
501 {
502 	struct req	*req;
503 	struct get_req	*r;
504 
505 	r = imsg->data;
506 
507 	if (datalen != sizeof(*r))
508 		die();
509 
510 	if ((req = calloc(1, sizeof(*req))) == NULL)
511 		die();
512 
513 	req->id = imsg->hdr.peerid;
514 	TAILQ_INSERT_HEAD(&reqhead, req, reqs);
515 
516 	strlcpy(req->url.host, r->host, sizeof(req->url.host));
517 	strlcpy(req->url.port, r->port, sizeof(req->url.port));
518 	strlcpy(req->buf, r->req, sizeof(req->buf));
519 
520 #if HAVE_ASR_RUN
521         async_conn_towards(req);
522 #else
523 	blocking_conn_towards(req);
524 #endif
525 }
526 
527 static void
528 handle_cert_status(struct imsg *imsg, size_t datalen)
529 {
530 	struct req	*req;
531 	int		 is_ok;
532 
533 	req = req_by_id(imsg->hdr.peerid);
534 
535 	if (datalen < sizeof(is_ok))
536 		die();
537 	memcpy(&is_ok, imsg->data, sizeof(is_ok));
538 
539 	if (is_ok)
540 		yield_w(req, write_request, NULL);
541 	else
542 		close_conn(0, 0, req);
543 }
544 
545 static void
546 handle_proceed(struct imsg *imsg, size_t datalen)
547 {
548 	yield_r(req_by_id(imsg->hdr.peerid),
549 	    copy_body, NULL);
550 }
551 
552 static void
553 handle_stop(struct imsg *imsg, size_t datalen)
554 {
555 	struct req	*req;
556 
557 	if ((req = req_by_id_try(imsg->hdr.peerid)) == NULL)
558 		return;
559 	close_conn(0, 0, req);
560 }
561 
562 static void
563 handle_quit(struct imsg *imsg, size_t datalen)
564 {
565 	event_loopbreak();
566 }
567 
568 static void
569 handle_dispatch_imsg(int fd, short ev, void *d)
570 {
571 	struct imsgev	*iev = d;
572 
573 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1)
574 		err(1, "connection closed");
575 }
576 
577 static int
578 net_send_ui(int type, uint32_t peerid, const void *data,
579     uint16_t datalen)
580 {
581 	return imsg_compose_event(iev_ui, type, peerid, 0, -1,
582 	    data, datalen);
583 }
584 
585 int
586 client_main(void)
587 {
588 	setproctitle("net");
589 
590 	TAILQ_INIT(&reqhead);
591 
592 	if ((tlsconf = tls_config_new()) == NULL)
593 		die();
594 	tls_config_insecure_noverifycert(tlsconf);
595 	tls_config_insecure_noverifyname(tlsconf);
596 
597 	event_init();
598 
599 	/* Setup pipe and event handler to the main process */
600 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
601 		die();
602 	imsg_init(&iev_ui->ibuf, 3);
603 	iev_ui->handler = handle_dispatch_imsg;
604 	iev_ui->events = EV_READ;
605 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
606 	    iev_ui->handler, iev_ui);
607 	event_add(&iev_ui->ev, NULL);
608 
609 	sandbox_net_process();
610 
611 	event_dispatch();
612 	return 0;
613 }