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Date:: Tue Sep 13 16:36:38 2022 UTC
Message:: initial import
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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 <limits.h>
33 #include <stdlib.h>
34 #include <stdint.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <imsg.h>
38 #include <tls.h>
39 #include <unistd.h>
40 
41 #include "log.h"
42 #include "proc.h"
43 
44 #include "galileo.h"
45 
46 #define MINIMUM(a, b)	((a) < (b) ? (a) : (b))
47 
48 /* provided by OpenBSD' base libevent but not in any header? */
49 extern void	 bufferevent_read_pressure_cb(struct evbuffer *, size_t,
50 		    size_t, void *);
51 
52 void	proxy_init(struct privsep *, struct privsep_proc *, void *);
53 int	proxy_launch(struct galileo *);
54 void	proxy_accept(int, short, void *);
55 void	proxy_inflight_dec(const char *);
56 int	proxy_dispatch_parent(int, struct privsep_proc *, struct imsg *);
57 void	proxy_resolved(struct asr_result *, void *);
58 void	proxy_connect(int, short, void *);
59 void	proxy_read(struct bufferevent *, void *);
60 void	proxy_write(struct bufferevent *, void *);
61 void	proxy_error(struct bufferevent *, short, void *);
62 int	proxy_bufferevent_add(struct event *, int);
63 void	proxy_tls_writecb(int, short, void *);
64 void	proxy_tls_readcb(int, short, void *);
65 
66 static struct privsep_proc procs[] = {
67 	{ "parent",	PROC_PARENT, proxy_dispatch_parent },
68 };
69 
70 volatile int proxy_clients;
71 volatile int proxy_inflight;
72 uint32_t proxy_fcg_id;
73 
74 void
75 proxy(struct privsep *ps, struct privsep_proc *p)
76 {
77 	proc_run(ps, p, procs, nitems(procs), proxy_init, NULL);
78 }
79 
80 void
81 proxy_init(struct privsep *ps, struct privsep_proc *p, void *arg)
82 {
83 	if (config_init(ps->ps_env) == -1)
84 		fatal("failed to initialize configuration");
85 
86 	/* We use a custom shutdown callback */
87 	/* p->p_shutdown = proxy_shutdown */
88 
89 	if (pledge("stdio recvfd unix inet dns", NULL) == -1)
90 		fatal("pledge");
91 }
92 
93 int
94 proxy_launch(struct galileo *env)
95 {
96 	event_add(&env->sc_evsock, NULL);
97 	return (0);
98 }
99 
100 void
101 proxy_purge(struct server *srv)
102 {
103 }
104 
105 void
106 proxy_accept(int fd, short event, void *arg)
107 {
108 	struct galileo	*env = arg;
109 
110 	log_debug("%s", __func__);
111 	fcgi_accept(env);
112 }
113 
114 void
115 proxy_inflight_dec(const char *why)
116 {
117 	proxy_inflight--;
118 	log_debug("%s: inflight decremented, now %d, %s",
119 	    __func__, proxy_inflight, why);
120 }
121 
122 int
123 proxy_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
124 {
125 	struct privsep	*ps = p->p_ps;
126 	struct galileo	*env = ps->ps_env;
127 
128 	switch (imsg->hdr.type) {
129 	case IMSG_CFG_SRV:
130 		if (config_getserver(env, imsg) == -1)
131 			fatal("config_getproxy");
132 		break;
133 	case IMSG_CFG_SOCK:
134 		/* XXX: improve */
135 
136 		if (env->sc_sock_fd != -1) {
137 			event_del(&env->sc_evsock);
138 			close(env->sc_sock_fd);
139 		}
140 
141 		env->sc_sock_fd = config_getsock(env, imsg);
142 		if (env->sc_sock_fd == -1)
143 			fatal("config_getsock");
144 
145 		event_set(&env->sc_evsock, env->sc_sock_fd,
146 		    EV_READ | EV_PERSIST, proxy_accept, env);
147 		event_add(&env->sc_evsock, NULL);
148 		/* evtimer_set(&env->sc_evpause, proxy_accept_paused, env); */
149 		break;
150 	case IMSG_CFG_DONE:
151 		log_debug("config done!");
152 		break;
153 	case IMSG_CTL_START:
154 		proxy_launch(env);
155 		break;
156 	default:
157 		log_warnx("unknown message %d", imsg->hdr.type);
158 		return (-1);
159 	}
160 
161 	return (0);
162 }
163 
164 static struct proxy_config *
165 proxy_server_match(struct galileo *env, struct client *clt)
166 {
167 	struct server		*srv;
168 
169 	if (clt->clt_server_name == NULL)
170 		return NULL;
171 
172 	TAILQ_FOREACH(srv, &env->sc_servers, srv_entry) {
173 		if (!strcmp(clt->clt_server_name, srv->srv_conf.host))
174 			return &srv->srv_conf;
175 	}
176 
177 	return NULL;
178 }
179 
180 void
181 proxy_start_request(struct galileo *env, struct client *clt)
182 {
183 	struct addrinfo		 hints;
184 	struct asr_query	*query;
185 	char			 port[32];
186 
187 	if ((clt->clt_pc = proxy_server_match(env, clt)) == NULL) {
188 		if (clt_printf(clt, "Status: 501\r\n\r\n") == -1)
189 			return;
190 		fcgi_end_request(clt, 1);
191 		return;
192 	}
193 
194 	(void)snprintf(port, sizeof(port), "%d", clt->clt_pc->proxy_port);
195 
196 	memset(&hints, 0, sizeof(hints));
197 	hints.ai_family = AF_UNSPEC;
198 	hints.ai_socktype = SOCK_STREAM;
199 
200 	query = getaddrinfo_async(clt->clt_pc->proxy_addr, port, &hints, NULL);
201 	if (query == NULL) {
202 		log_warn("getaddrinfo_async");
203 		fcgi_abort_request(clt);
204 		return;
205 	}
206 
207 	clt->clt_evasr = event_asr_run(query, proxy_resolved, clt);
208 	if (clt->clt_evasr == NULL) {
209 		log_warn("event_asr_run");
210 		asr_abort(query);
211 		fcgi_abort_request(clt);
212 		return;
213 	}
214 }
215 
216 void
217 proxy_resolved(struct asr_result *res, void *d)
218 {
219 	struct client		*clt = d;
220 	struct proxy_config	*pc = clt->clt_pc;
221 
222 	clt->clt_evasr = NULL;
223 
224 	if (res->ar_gai_errno != 0) {
225 		log_warnx("failed to resolve %s:%d: %s",
226 		    pc->proxy_addr, pc->proxy_port,
227 		    gai_strerror(res->ar_gai_errno));
228 		if (clt_printf(clt, "Status: 501\r\n") == -1)
229 			return;
230 		if (clt_printf(clt, "Content-Type: text/plain\r\n") == -1)
231 			return;
232 		if (clt_printf(clt, "Proxy error; connection failed") == -1)
233 			return;
234 		fcgi_end_request(clt, 1);
235 		return;
236 	}
237 
238 	clt->clt_addrinfo = res->ar_addrinfo;
239 	clt->clt_p = clt->clt_addrinfo;
240 	proxy_connect(-1, 0, clt);
241 }
242 
243 void
244 proxy_connect(int fd, short ev, void *d)
245 {
246 	struct client		*clt = d;
247 	struct evbuffer		*out;
248 	struct addrinfo		*p;
249 	struct tls_config	*conf;
250 	struct timeval		 conntv = {5, 0};
251 	int			 err = 0;
252 	socklen_t		 len = sizeof(err);
253 
254 again:
255 	if (clt->clt_p == NULL)
256 		goto err;
257 
258 	if (clt->clt_fd != -1) {
259 		if (getsockopt(clt->clt_fd, SOL_SOCKET, SO_ERROR, &err, &len)
260 		    == -1)
261 			goto err;
262 		if (err != 0) {
263 			errno = err;
264 			goto err;
265 		}
266 		goto done;
267 	}
268 
269 	p = clt->clt_p;
270 	clt->clt_fd = socket(p->ai_family, p->ai_socktype | SOCK_NONBLOCK,
271 	    p->ai_protocol);
272 	if (clt->clt_fd == -1) {
273 		clt->clt_p = clt->clt_p->ai_next;
274 		goto again;
275 	}
276 
277 	if (connect(clt->clt_fd, p->ai_addr, p->ai_addrlen) == 0)
278 		goto done;
279 
280 	clt->clt_evconn_live = 1;
281 	event_set(&clt->clt_evconn, clt->clt_fd, EV_WRITE, proxy_connect, clt);
282 	event_add(&clt->clt_evconn, &conntv);
283 	return;
284 
285 done:
286 	clt->clt_evconn_live = 0;
287 	freeaddrinfo(clt->clt_addrinfo);
288 	clt->clt_addrinfo = clt->clt_p = NULL;
289 
290 	/* initialize TLS for Gemini */
291 	if ((conf = tls_config_new()) == NULL) {
292 		log_warn("tls_config_new failed");
293 		goto err;
294 	}
295 
296 	tls_config_insecure_noverifycert(conf);
297 
298 	if ((clt->clt_ctx = tls_client()) == NULL) {
299 		log_warnx("tls_client failed");
300 		tls_config_free(conf);
301 		goto err;
302 	}
303 
304 	if (tls_configure(clt->clt_ctx, conf) == -1) {
305 		log_warnx("tls_configure failed");
306 		tls_config_free(conf);
307 		goto err;
308 	}
309 
310 	tls_config_free(conf);
311 
312 	if (tls_connect_socket(clt->clt_ctx, clt->clt_fd,
313 	    clt->clt_pc->proxy_name) == -1) {
314 		log_warnx("tls_connect_socket failed");
315 		goto err;
316 	}
317 
318 	clt->clt_bev = bufferevent_new(clt->clt_fd, proxy_read, proxy_write,
319 	    proxy_error, clt);
320 	if (clt->clt_bev == NULL) {
321 		log_warn("bufferevent_new");
322 		goto err;
323 	}
324 	out = EVBUFFER_OUTPUT(clt->clt_bev);
325 
326 	event_set(&clt->clt_bev->ev_read, clt->clt_fd, EV_READ,
327 	    proxy_tls_readcb, clt->clt_bev);
328 	event_set(&clt->clt_bev->ev_write, clt->clt_fd, EV_WRITE,
329 	    proxy_tls_writecb, clt->clt_bev);
330 
331 	/* bufferevent_settimeout(); */
332 	bufferevent_enable(clt->clt_bev, EV_READ|EV_WRITE);
333 
334 	/* TODO: compute the URL */
335 	if (evbuffer_add_printf(out, "gemini://localhost/\r\n") == -1) {
336 		log_warn("bufferevent_printf failed");
337 		goto err;
338 	}
339 
340 	return;
341 
342 err:
343 	log_warn("failed to connect to %s:%d",
344 	    clt->clt_pc->proxy_addr, clt->clt_pc->proxy_port);
345 	if (clt_printf(clt, "Status: 501\r\n") == -1)
346 		return;
347 	if (clt_printf(clt, "Content-Type: text/plain\r\n") == -1)
348 		return;
349 	if (clt_printf(clt, "Proxy error; connection failed") == -1)
350 		return;
351 	fcgi_end_request(clt, 1);
352 }
353 
354 void
355 proxy_read(struct bufferevent *bev, void *d)
356 {
357 	struct client		*clt = d;
358 	struct evbuffer		*src = EVBUFFER_INPUT(bev);
359 	char			*hdr;
360 	size_t			 len;
361 	int			 code;
362 
363 	if (clt->clt_headersdone) {
364 	copy:
365 		clt_write_bufferevent(clt, bev);
366 		return;
367 	}
368 
369 	hdr = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
370 	if (hdr == NULL) {
371 		if (EVBUFFER_LENGTH(src) >= 1026)
372 			proxy_error(bev, EV_READ, clt);
373 		return;
374 	}
375 
376 	if (len < 4 ||
377 	    !isdigit((unsigned char)hdr[0]) ||
378 	    !isdigit((unsigned char)hdr[1]) ||
379 	    hdr[2] != ' ') {
380 		log_warnx("invalid ");
381 		free(hdr);
382 		proxy_error(bev, EV_READ, clt);
383 		return;
384 	}
385 
386 	code = (hdr[0] - '0') * 10 + (hdr[1] - '0');
387 	if (code != 20) {
388 		log_warnx("un-handled gemini reply status %d", code);
389 		free(hdr);
390 		proxy_error(bev, EV_READ, clt);
391 		return;
392 	}
393 
394 	if (clt_printf(clt, "Content-Type: %s\r\n", &hdr[4]) == -1)
395 		return;
396 	if (clt_printf(clt, "\r\n") == -1)
397 		return;
398 
399 	clt->clt_headersdone = 1;
400 	goto copy;
401 }
402 
403 void
404 proxy_write(struct bufferevent *bev, void *d)
405 {
406 	return;
407 }
408 
409 void
410 proxy_error(struct bufferevent *bev, short err, void *d)
411 {
412 	struct client		*clt = d;
413 	int			 status = !(err & EVBUFFER_EOF);
414 
415 	log_debug("proxy error, shutting down the connection (err: %x)",
416 	    err);
417 
418 	if (!clt->clt_headersdone) {
419 		if (clt_printf(clt, "Status: 501\r\n") == -1)
420 			return;
421 		if (clt_printf(clt, "Content-Type: text/plain\r\n") == -1)
422 			return;
423 		if (clt_printf(clt, "Proxy error\n") == -1)
424 			return;
425 	}
426 
427 	fcgi_end_request(clt, status);
428 }
429 
430 void
431 proxy_tls_readcb(int fd, short event, void *arg)
432 {
433 	struct bufferevent	*bufev = arg;
434 	struct client		*clt = bufev->cbarg;
435 	char			 rbuf[IBUF_READ_SIZE];
436 	int			 what = EVBUFFER_READ;
437 	int			 howmuch = IBUF_READ_SIZE;
438 	ssize_t			 ret;
439 	size_t			 len;
440 
441 	if (event == EV_TIMEOUT) {
442 		what |= EVBUFFER_TIMEOUT;
443 		goto err;
444 	}
445 
446 	if (bufev->wm_read.high != 0)
447 		howmuch = MINIMUM(sizeof(rbuf), bufev->wm_read.high);
448 
449 	ret = tls_read(clt->clt_ctx, rbuf, howmuch);
450 	if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) {
451 		goto retry;
452 	} else if (ret == -1) {
453 		what |= EVBUFFER_ERROR;
454 		goto err;
455 	}
456 	len = ret;
457 
458 	if (len == 0) {
459 		what |= EVBUFFER_EOF;
460 		goto err;
461 	}
462 
463 	if (evbuffer_add(bufev->input, rbuf, len) == -1) {
464 		what |= EVBUFFER_ERROR;
465 		goto err;
466 	}
467 
468 	proxy_bufferevent_add(&bufev->ev_read, bufev->timeout_read);
469 
470 	len = EVBUFFER_LENGTH(bufev->input);
471 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
472 		return;
473 	if (bufev->wm_read.high != 0 && len > bufev->wm_read.high) {
474 		struct evbuffer *buf = bufev->input;
475 		event_del(&bufev->ev_read);
476 		evbuffer_setcb(buf, bufferevent_read_pressure_cb, bufev);
477 		return;
478 	}
479 
480 	if (bufev->readcb != NULL)
481 		(*bufev->readcb)(bufev, bufev->cbarg);
482 	return;
483 
484 retry:
485 	proxy_bufferevent_add(&bufev->ev_read, bufev->timeout_read);
486 	return;
487 
488 err:
489 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
490 }
491 
492 int
493 proxy_bufferevent_add(struct event *ev, int timeout)
494 {
495 	struct timeval tv, *ptv = NULL;
496 
497 	if (timeout) {
498 		timerclear(&tv);
499 		tv.tv_sec = timeout;
500 		ptv = &tv;
501 	}
502 
503 	return (event_add(ev, ptv));
504 }
505 
506 void
507 proxy_tls_writecb(int fd, short event, void *arg)
508 {
509 	struct bufferevent	*bufev = arg;
510 	struct client		*clt = bufev->cbarg;
511 	ssize_t			 ret;
512 	short			 what = EVBUFFER_WRITE;
513 	size_t			 len;
514 
515 	if (event == EV_TIMEOUT) {
516 		what |= EVBUFFER_TIMEOUT;
517 		goto err;
518 	}
519 
520 	if (EVBUFFER_LENGTH(bufev->output)) {
521 		ret = tls_write(clt->clt_ctx,
522 		    EVBUFFER_DATA(bufev->output),
523 		    EVBUFFER_LENGTH(bufev->output));
524 		if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) {
525 			goto retry;
526 		} else if (ret == -1) {
527 			what |= EVBUFFER_ERROR;
528 			goto err;
529 		}
530 		len = ret;
531 		evbuffer_drain(bufev->output, len);
532 	}
533 
534 	if (EVBUFFER_LENGTH(bufev->output) != 0)
535 		proxy_bufferevent_add(&bufev->ev_write, bufev->timeout_write);
536 
537 	if (bufev->writecb != NULL &&
538 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
539 		(*bufev->writecb)(bufev, bufev->cbarg);
540 	return;
541 
542 retry:
543 	proxy_bufferevent_add(&bufev->ev_write, bufev->timeout_write);
544 	return;
545 
546 err:
547 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
548 }
549 
550 void
551 proxy_client_free(struct client *clt)
552 {
553 	if (clt->clt_evasr)
554 		event_asr_abort(clt->clt_evasr);
555 
556 	if (clt->clt_addrinfo)
557 		freeaddrinfo(clt->clt_addrinfo);
558 
559 	if (clt->clt_evconn_live)
560 		event_del(&clt->clt_evconn);
561 
562 	if (clt->clt_fd != -1)
563 		close(clt->clt_fd);
564 
565 	if (clt->clt_ctx)
566 		tls_free(clt->clt_ctx);
567 
568 	if (clt->clt_bev)
569 		bufferevent_free(clt->clt_bev);
570 
571 	free(clt->clt_server_name);
572 	free(clt->clt_script_name);
573 	free(clt->clt_path_info);
574 	free(clt);
575 }