1 /*
2  * Copyright (c) 2016, 2019, 2020-2021 Tracey Emery <tracey@traceyemery.net>
3  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
4  * Copyright (c) 2013 David Gwynne <dlg@openbsd.org>
5  * Copyright (c) 2013 Florian Obser <florian@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include "got_compat.h"
21 
22 #include <sys/param.h>
23 #include <sys/ioctl.h>
24 #include <sys/queue.h>
25 #include <sys/wait.h>
26 #include <sys/uio.h>
27 #include <sys/resource.h>
28 #include <sys/socket.h>
29 #include <sys/stat.h>
30 #include <sys/time.h>
31 #include <sys/types.h>
32 #include <sys/mman.h>
33 #include <sys/un.h>
34 
35 #include <net/if.h>
36 #include <netinet/in.h>
37 
38 #include <errno.h>
39 #include <event.h>
40 #include <fcntl.h>
41 #include <ifaddrs.h>
42 #include <limits.h>
43 #include <netdb.h>
44 #include <poll.h>
45 #include <pwd.h>
46 #include <stddef.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 
52 #include "got_error.h"
53 #include "got_opentemp.h"
54 #include "got_reference.h"
55 #include "got_repository.h"
56 
57 #include "proc.h"
58 #include "gotwebd.h"
59 #include "tmpl.h"
60 
61 #define SOCKS_BACKLOG 5
62 #define MAXIMUM(a, b)	(((a) > (b)) ? (a) : (b))
63 
64 
65 volatile int client_cnt;
66 
67 static struct timeval	timeout = { TIMEOUT_DEFAULT, 0 };
68 
69 static void	 sockets_sighdlr(int, short, void *);
70 static void	 sockets_run(struct privsep *, struct privsep_proc *, void *);
71 static void	 sockets_launch(void);
72 static void	 sockets_purge(struct gotwebd *);
73 static void	 sockets_accept_paused(int, short, void *);
74 static void	 sockets_rlimit(int);
75 
76 static int	 sockets_dispatch_gotwebd(int, struct privsep_proc *,
77 		    struct imsg *);
78 static int	 sockets_unix_socket_listen(struct privsep *, struct socket *);
79 static int	 sockets_create_socket(struct address *, in_port_t);
80 static int	 sockets_accept_reserve(int, struct sockaddr *, socklen_t *,
81 		    int, volatile int *);
82 
83 static struct socket *sockets_conf_new_socket_unix(struct gotwebd *,
84 		    struct server *, int);
85 static struct socket *sockets_conf_new_socket_fcgi(struct gotwebd *,
86 		    struct server *, int, struct address *);
87 
88 int cgi_inflight = 0;
89 
90 static struct privsep_proc procs[] = {
91 	{ "gotwebd",	PROC_GOTWEBD,	sockets_dispatch_gotwebd  },
92 };
93 
94 void
95 sockets(struct privsep *ps, struct privsep_proc *p)
96 {
97 	proc_run(ps, p, procs, nitems(procs), sockets_run, NULL);
98 }
99 
100 static void
101 sockets_run(struct privsep *ps, struct privsep_proc *p, void *arg)
102 {
103 	if (config_init(ps->ps_env) == -1)
104 		fatal("failed to initialize configuration");
105 
106 	p->p_shutdown = sockets_shutdown;
107 
108 	sockets_rlimit(-1);
109 
110 	signal_del(&ps->ps_evsigchld);
111 	signal_set(&ps->ps_evsigchld, SIGCHLD, sockets_sighdlr, ps);
112 	signal_add(&ps->ps_evsigchld, NULL);
113 
114 #ifndef PROFILE
115 	if (pledge("stdio rpath wpath cpath inet recvfd proc exec sendfd",
116 	    NULL) == -1)
117 		fatal("pledge");
118 #endif
119 }
120 
121 void
122 sockets_parse_sockets(struct gotwebd *env)
123 {
124 	struct server *srv;
125 	struct address *a;
126 	struct socket *new_sock = NULL;
127 	int sock_id = 1;
128 
129 	TAILQ_FOREACH(srv, &env->servers, entry) {
130 		if (srv->unix_socket) {
131 			new_sock = sockets_conf_new_socket_unix(env, srv,
132 			    sock_id);
133 			if (new_sock) {
134 				sock_id++;
135 				TAILQ_INSERT_TAIL(&env->sockets, new_sock,
136 				    entry);
137 			}
138 		}
139 
140 		if (srv->fcgi_socket) {
141 			if (TAILQ_EMPTY(&srv->al)) {
142 				fatalx("%s: server %s has no IP addresses to "
143 				    "listen for FCGI connections", __func__,
144 				    srv->name);
145 			}
146 			TAILQ_FOREACH(a, &srv->al, entry) {
147 				if (a->ss.ss_family != AF_INET &&
148 				    a->ss.ss_family != AF_INET6)
149 					continue;
150 				new_sock = sockets_conf_new_socket_fcgi(env,
151 				    srv, sock_id, a);
152 				if (new_sock) {
153 					sock_id++;
154 					TAILQ_INSERT_TAIL(&env->sockets,
155 					    new_sock, entry);
156 				}
157 			}
158 		}
159 	}
160 }
161 
162 static struct socket *
163 sockets_conf_new_socket_unix(struct gotwebd *env, struct server *srv, int id)
164 {
165 	struct socket *sock;
166 	int n;
167 
168 	if ((sock = calloc(1, sizeof(*sock))) == NULL)
169 		fatalx("%s: calloc", __func__);
170 
171 	sock->conf.id = id;
172 	sock->fd = -1;
173 	sock->conf.af_type = AF_UNIX;
174 
175 	if (strlcpy(sock->conf.unix_socket_name,
176 	    srv->unix_socket_name,
177 	    sizeof(sock->conf.unix_socket_name)) >=
178 	    sizeof(sock->conf.unix_socket_name)) {
179 		free(sock);
180 		fatalx("%s: strlcpy", __func__);
181 	}
182 
183 	n = snprintf(sock->conf.name, GOTWEBD_MAXTEXT, "%s_parent",
184 	    srv->name);
185 	if (n < 0 || (size_t)n >= GOTWEBD_MAXTEXT) {
186 		free(sock);
187 		fatalx("%s: snprintf", __func__);
188 	}
189 
190 	if (strlcpy(sock->conf.srv_name, srv->name,
191 	    sizeof(sock->conf.srv_name)) >= sizeof(sock->conf.srv_name)) {
192 		free(sock);
193 		fatalx("%s: strlcpy", __func__);
194 	}
195 
196 	return sock;
197 }
198 
199 static struct socket *
200 sockets_conf_new_socket_fcgi(struct gotwebd *env, struct server *srv, int id,
201     struct address *a)
202 {
203 	struct socket *sock;
204 	struct address *acp;
205 	int n;
206 
207 	if ((sock = calloc(1, sizeof(*sock))) == NULL)
208 		fatalx("%s: calloc", __func__);
209 
210 	sock->conf.id = id;
211 	sock->fd = -1;
212 	sock->conf.af_type = a->ss.ss_family;
213 
214 	sock->conf.fcgi_socket_port = a->port;
215 
216 	n = snprintf(sock->conf.name, GOTWEBD_MAXTEXT, "%s_parent",
217 	    srv->name);
218 	if (n < 0 || (size_t)n >= GOTWEBD_MAXTEXT) {
219 		free(sock);
220 		fatalx("%s: snprintf", __func__);
221 	}
222 
223 	if (strlcpy(sock->conf.srv_name, srv->name,
224 	    sizeof(sock->conf.srv_name)) >= sizeof(sock->conf.srv_name)) {
225 		free(sock);
226 		fatalx("%s: strlcpy", __func__);
227 	}
228 
229 	acp = &sock->conf.addr;
230 
231 	memcpy(&acp->ss, &a->ss, sizeof(acp->ss));
232 	acp->ipproto = a->ipproto;
233 	acp->port = a->port;
234 	if (*a->ifname != '\0') {
235 		if (strlcpy(acp->ifname, a->ifname,
236 		    sizeof(acp->ifname)) >= sizeof(acp->ifname)) {
237 			fatalx("%s: interface name truncated",
238 			    __func__);
239 		}
240 	}
241 
242 	return (sock);
243 }
244 
245 static void
246 sockets_launch(void)
247 {
248 	struct socket *sock;
249 
250 	TAILQ_FOREACH(sock, &gotwebd_env->sockets, entry) {
251 		log_debug("%s: configuring socket %d (%d)", __func__,
252 		    sock->conf.id, sock->fd);
253 
254 		event_set(&sock->ev, sock->fd, EV_READ | EV_PERSIST,
255 		    sockets_socket_accept, sock);
256 
257 		if (event_add(&sock->ev, NULL))
258 			fatalx("event add sock");
259 
260 		evtimer_set(&sock->pause, sockets_accept_paused, sock);
261 
262 		log_debug("%s: running socket listener %d", __func__,
263 		    sock->conf.id);
264 	}
265 }
266 
267 static void
268 sockets_purge(struct gotwebd *env)
269 {
270 	struct socket *sock, *tsock;
271 
272 	/* shutdown and remove sockets */
273 	TAILQ_FOREACH_SAFE(sock, &env->sockets, entry, tsock) {
274 		if (event_initialized(&sock->ev))
275 			event_del(&sock->ev);
276 		if (evtimer_initialized(&sock->evt))
277 			evtimer_del(&sock->evt);
278 		if (evtimer_initialized(&sock->pause))
279 			evtimer_del(&sock->pause);
280 		if (sock->fd != -1)
281 			close(sock->fd);
282 		TAILQ_REMOVE(&env->sockets, sock, entry);
283 	}
284 }
285 
286 static int
287 sockets_dispatch_gotwebd(int fd, struct privsep_proc *p, struct imsg *imsg)
288 {
289 	struct privsep *ps = p->p_ps;
290 	int res = 0, cmd = 0, verbose;
291 
292 	switch (imsg->hdr.type) {
293 	case IMSG_CFG_SRV:
294 		config_getserver(gotwebd_env, imsg);
295 		break;
296 	case IMSG_CFG_SOCK:
297 		config_getsock(gotwebd_env, imsg);
298 		break;
299 	case IMSG_CFG_FD:
300 		config_getfd(gotwebd_env, imsg);
301 		break;
302 	case IMSG_CFG_DONE:
303 		config_getcfg(gotwebd_env, imsg);
304 		break;
305 	case IMSG_CTL_START:
306 		sockets_launch();
307 		break;
308 	case IMSG_CTL_VERBOSE:
309 		IMSG_SIZE_CHECK(imsg, &verbose);
310 		memcpy(&verbose, imsg->data, sizeof(verbose));
311 		log_setverbose(verbose);
312 		break;
313 	default:
314 		return -1;
315 	}
316 
317 	switch (cmd) {
318 	case 0:
319 		break;
320 	default:
321 		if (proc_compose_imsg(ps, PROC_GOTWEBD, -1, cmd,
322 		    imsg->hdr.peerid, -1, &res, sizeof(res)) == -1)
323 			return -1;
324 		break;
325 	}
326 
327 	return 0;
328 }
329 
330 static void
331 sockets_sighdlr(int sig, short event, void *arg)
332 {
333 	switch (sig) {
334 	case SIGHUP:
335 		log_info("%s: ignoring SIGHUP", __func__);
336 		break;
337 	case SIGPIPE:
338 		log_info("%s: ignoring SIGPIPE", __func__);
339 		break;
340 	case SIGUSR1:
341 		log_info("%s: ignoring SIGUSR1", __func__);
342 		break;
343 	case SIGCHLD:
344 		break;
345 	default:
346 		log_info("SIGNAL: %d", sig);
347 		fatalx("unexpected signal");
348 	}
349 }
350 
351 void
352 sockets_shutdown(void)
353 {
354 	struct server *srv, *tsrv;
355 	struct socket *sock, *tsock;
356 	int i;
357 
358 	sockets_purge(gotwebd_env);
359 
360 	/* clean sockets */
361 	TAILQ_FOREACH_SAFE(sock, &gotwebd_env->sockets, entry, tsock) {
362 		TAILQ_REMOVE(&gotwebd_env->sockets, sock, entry);
363 		close(sock->fd);
364 		free(sock);
365 	}
366 
367 	/* clean servers */
368 	TAILQ_FOREACH_SAFE(srv, &gotwebd_env->servers, entry, tsrv) {
369 		for (i = 0; i < srv->ncached_repos; i++)
370 			got_repo_close(srv->cached_repos[i].repo);
371 		free(srv);
372 	}
373 
374 	free(gotwebd_env);
375 }
376 
377 int
378 sockets_privinit(struct gotwebd *env, struct socket *sock)
379 {
380 	struct privsep *ps = env->gotwebd_ps;
381 
382 	if (sock->conf.af_type == AF_UNIX) {
383 		log_debug("%s: initializing unix socket %s", __func__,
384 		    sock->conf.unix_socket_name);
385 		sock->fd = sockets_unix_socket_listen(ps, sock);
386 		if (sock->fd == -1) {
387 			log_warnx("%s: create unix socket failed", __func__);
388 			return -1;
389 		}
390 	}
391 
392 	if (sock->conf.af_type == AF_INET || sock->conf.af_type == AF_INET6) {
393 		log_debug("%s: initializing %s FCGI socket on port %d for %s",
394 		    __func__, sock->conf.af_type == AF_INET ? "inet" : "inet6",
395 		    sock->conf.fcgi_socket_port, sock->conf.name);
396 		sock->fd = sockets_create_socket(&sock->conf.addr,
397 		    sock->conf.fcgi_socket_port);
398 		if (sock->fd == -1) {
399 			log_warnx("%s: create FCGI socket failed", __func__);
400 			return -1;
401 		}
402 	}
403 
404 	return 0;
405 }
406 
407 static int
408 sockets_unix_socket_listen(struct privsep *ps, struct socket *sock)
409 {
410 	struct gotwebd *env = ps->ps_env;
411 	struct sockaddr_un sun;
412 	struct socket *tsock;
413 	int u_fd = -1;
414 	mode_t old_umask, mode;
415 
416 	TAILQ_FOREACH(tsock, &env->sockets, entry) {
417 		if (strcmp(tsock->conf.unix_socket_name,
418 		    sock->conf.unix_socket_name) == 0 &&
419 		    tsock->fd != -1)
420 			return (tsock->fd);
421 	}
422 
423 	/* TA: FIXME:  this needs upstreaming. */
424 	int socket_flags = SOCK_STREAM | SOCK_NONBLOCK;
425 #ifdef SOCK_CLOEXEC
426 	socket_flags |= SOCK_CLOEXEC;
427 #endif
428 	u_fd = socket(AF_UNIX, socket_flags, 0);
429 	if (u_fd == -1) {
430 		log_warn("%s: socket", __func__);
431 		return -1;
432 	}
433 
434 	sun.sun_family = AF_UNIX;
435 	if (strlcpy(sun.sun_path, sock->conf.unix_socket_name,
436 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
437 		log_warn("%s: %s name too long", __func__,
438 		    sock->conf.unix_socket_name);
439 		close(u_fd);
440 		return -1;
441 	}
442 
443 	if (unlink(sock->conf.unix_socket_name) == -1) {
444 		if (errno != ENOENT) {
445 			log_warn("%s: unlink %s", __func__,
446 			    sock->conf.unix_socket_name);
447 			close(u_fd);
448 			return -1;
449 		}
450 	}
451 
452 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
453 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP;
454 
455 	if (bind(u_fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
456 		log_warn("%s: bind: %s", __func__, sock->conf.unix_socket_name);
457 		close(u_fd);
458 		(void)umask(old_umask);
459 		return -1;
460 	}
461 
462 	(void)umask(old_umask);
463 
464 	if (chmod(sock->conf.unix_socket_name, mode) == -1) {
465 		log_warn("%s: chmod", __func__);
466 		close(u_fd);
467 		(void)unlink(sock->conf.unix_socket_name);
468 		return -1;
469 	}
470 
471 	if (chown(sock->conf.unix_socket_name, ps->ps_pw->pw_uid,
472 	    ps->ps_pw->pw_gid) == -1) {
473 		log_warn("%s: chown", __func__);
474 		close(u_fd);
475 		(void)unlink(sock->conf.unix_socket_name);
476 		return -1;
477 	}
478 
479 	if (listen(u_fd, SOCKS_BACKLOG) == -1) {
480 		log_warn("%s: listen", __func__);
481 		return -1;
482 	}
483 
484 	return u_fd;
485 }
486 
487 static int
488 sockets_create_socket(struct address *a, in_port_t port)
489 {
490 	struct addrinfo hints;
491 	int fd = -1, o_val = 1, flags;
492 
493 	memset(&hints, 0, sizeof(hints));
494 	hints.ai_family = AF_UNSPEC;
495 	hints.ai_socktype = SOCK_STREAM;
496 	hints.ai_flags |= AI_PASSIVE;
497 
498 	switch (a->ss.ss_family) {
499 	case AF_INET:
500 		((struct sockaddr_in *)(&a->ss))->sin_port = htons(port);
501 		break;
502 	case AF_INET6:
503 		((struct sockaddr_in6 *)(&a->ss))->sin6_port = htons(port);
504 		break;
505 	default:
506 		log_warnx("%s: unknown address family", __func__);
507 		return -1;
508 	}
509 
510 	fd = socket(a->ss.ss_family, hints.ai_socktype, a->ipproto);
511 	if (fd == -1)
512 		return -1;
513 
514 	log_debug("%s: opened socket (%d) for %s", __func__,
515 	    fd, a->ifname);
516 
517 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &o_val,
518 	    sizeof(int)) == -1) {
519 		log_warn("%s: setsockopt error", __func__);
520 		close(fd);
521 		return -1;
522 	}
523 
524 	/* non-blocking */
525 	flags = fcntl(fd, F_GETFL);
526 	flags |= O_NONBLOCK;
527 	if (fcntl(fd, F_SETFL, flags) == -1) {
528 		log_info("%s: could not enable non-blocking I/O", __func__);
529 		close(fd);
530 		return -1;
531 	}
532 
533 	if (bind(fd, (struct sockaddr *)&a->ss, SS_LEN(&a->ss)) == -1) {
534 		close(fd);
535 		log_info("%s: can't bind to port %d", __func__,
536 		    ntohs(port));
537 		return -1;
538 	}
539 
540 	if (listen(fd, SOMAXCONN) == -1) {
541 		log_warn("%s, unable to listen on socket", __func__);
542 		close(fd);
543 		return -1;
544 	}
545 
546 	return (fd);
547 }
548 
549 static int
550 sockets_accept_reserve(int sockfd, struct sockaddr *addr, socklen_t *addrlen,
551     int reserve, volatile int *counter)
552 {
553 	int ret;
554 
555 	if (getdtablecount() + reserve +
556 	    ((*counter + 1) * FD_NEEDED) >= getdtablesize()) {
557 		log_debug("inflight fds exceeded");
558 		errno = EMFILE;
559 		return -1;
560 	}
561 /* TA:  This needs fixing upstream. */
562 #ifdef __APPLE__
563 	ret = accept(sockfd, addr, addrlen);
564 #else
565 	ret = accept4(sockfd, addr, addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);
566 #endif
567 
568 	if (ret > -1) {
569 		(*counter)++;
570 		log_debug("inflight incremented, now %d", *counter);
571 	}
572 
573 	return ret;
574 }
575 
576 static void
577 sockets_accept_paused(int fd, short events, void *arg)
578 {
579 	struct socket *sock = (struct socket *)arg;
580 
581 	event_add(&sock->ev, NULL);
582 }
583 
584 void
585 sockets_socket_accept(int fd, short event, void *arg)
586 {
587 	struct socket *sock = (struct socket *)arg;
588 	struct sockaddr_storage ss;
589 	struct timeval backoff;
590 	struct request *c = NULL;
591 	socklen_t len;
592 	int s;
593 
594 	backoff.tv_sec = 1;
595 	backoff.tv_usec = 0;
596 
597 	event_add(&sock->ev, NULL);
598 	if (event & EV_TIMEOUT)
599 		return;
600 
601 	len = sizeof(ss);
602 
603 	s = sockets_accept_reserve(fd, (struct sockaddr *)&ss, &len,
604 	    FD_RESERVE, &cgi_inflight);
605 
606 	if (s == -1) {
607 		switch (errno) {
608 		case EINTR:
609 		case EWOULDBLOCK:
610 		case ECONNABORTED:
611 			return;
612 		case EMFILE:
613 		case ENFILE:
614 			event_del(&sock->ev);
615 			evtimer_add(&sock->pause, &backoff);
616 			return;
617 		default:
618 			log_warn("%s: accept", __func__);
619 		}
620 	}
621 
622 	if (client_cnt > GOTWEBD_MAXCLIENTS)
623 		goto err;
624 
625 	c = calloc(1, sizeof(struct request));
626 	if (c == NULL) {
627 		log_warn("%s", __func__);
628 		close(s);
629 		cgi_inflight--;
630 		return;
631 	}
632 
633 	c->tp = template(c, fcgi_puts, fcgi_putc);
634 	if (c->tp == NULL) {
635 		log_warn("%s", __func__);
636 		close(s);
637 		cgi_inflight--;
638 		free(c);
639 		return;
640 	}
641 
642 	c->fd = s;
643 	c->sock = sock;
644 	memcpy(c->priv_fd, sock->priv_fd, sizeof(c->priv_fd));
645 	c->buf_pos = 0;
646 	c->buf_len = 0;
647 	c->request_started = 0;
648 	c->sock->client_status = CLIENT_CONNECT;
649 
650 	event_set(&c->ev, s, EV_READ|EV_PERSIST, fcgi_request, c);
651 	event_add(&c->ev, NULL);
652 
653 	evtimer_set(&c->tmo, fcgi_timeout, c);
654 	evtimer_add(&c->tmo, &timeout);
655 
656 	client_cnt++;
657 
658 	return;
659 err:
660 	cgi_inflight--;
661 	close(s);
662 	if (c != NULL)
663 		free(c);
664 }
665 
666 static void
667 sockets_rlimit(int maxfd)
668 {
669 	struct rlimit rl;
670 
671 	if (getrlimit(RLIMIT_NOFILE, &rl) == -1)
672 		fatal("%s: failed to get resource limit", __func__);
673 	log_debug("%s: max open files %llu", __func__,
674 	    (unsigned long long)rl.rlim_max);
675 
676 	/*
677 	 * Allow the maximum number of open file descriptors for this
678 	 * login class (which should be the class "daemon" by default).
679 	 */
680 	if (maxfd == -1)
681 		rl.rlim_cur = rl.rlim_max;
682 	else
683 		rl.rlim_cur = MAXIMUM(rl.rlim_max, (rlim_t)maxfd);
684 	if (setrlimit(RLIMIT_NOFILE, &rl) == -1)
685 		fatal("%s: failed to set resource limit", __func__);
686 }