1 /*
2  * Copyright (c) 2024 Stefan Sperling <stsp@openbsd.org>
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 <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/tree.h>
20 #include <sys/socket.h>
21 #include <sys/wait.h>
22 
23 #include <errno.h>
24 #include <event.h>
25 #include <siphash.h>
26 #include <limits.h>
27 #include <sha1.h>
28 #include <sha2.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <imsg.h>
34 #include <unistd.h>
35 
36 #include "got_error.h"
37 #include "got_path.h"
38 
39 #include "gotd.h"
40 #include "log.h"
41 #include "notify.h"
42 
43 #ifndef nitems
44 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
45 #endif
46 
47 static struct gotd_notify {
48 	pid_t pid;
49 	const char *title;
50 	struct gotd_imsgev parent_iev;
51 	struct gotd_repolist *repos;
52 	const char *default_sender;
53 } gotd_notify;
54 
55 struct gotd_notify_session {
56 	STAILQ_ENTRY(gotd_notify_session) entry;
57 	uint32_t id;
58 	struct gotd_imsgev iev;
59 };
60 STAILQ_HEAD(gotd_notify_sessions, gotd_notify_session);
61 
62 static struct gotd_notify_sessions gotd_notify_sessions[GOTD_CLIENT_TABLE_SIZE];
63 static SIPHASH_KEY sessions_hash_key;
64 
65 static void gotd_notify_shutdown(void);
66 
67 static uint64_t
68 session_hash(uint32_t session_id)
69 {
70 	return SipHash24(&sessions_hash_key, &session_id, sizeof(session_id));
71 }
72 
73 static void
74 add_session(struct gotd_notify_session *session)
75 {
76 	uint64_t slot;
77 
78 	slot = session_hash(session->id) % nitems(gotd_notify_sessions);
79 	STAILQ_INSERT_HEAD(&gotd_notify_sessions[slot], session, entry);
80 }
81 
82 static struct gotd_notify_session *
83 find_session(uint32_t session_id)
84 {
85 	uint64_t slot;
86 	struct gotd_notify_session *s;
87 
88 	slot = session_hash(session_id) % nitems(gotd_notify_sessions);
89 	STAILQ_FOREACH(s, &gotd_notify_sessions[slot], entry) {
90 		if (s->id == session_id)
91 			return s;
92 	}
93 
94 	return NULL;
95 }
96 
97 static struct gotd_notify_session *
98 find_session_by_fd(int fd)
99 {
100 	uint64_t slot;
101 	struct gotd_notify_session *s;
102 
103 	for (slot = 0; slot < nitems(gotd_notify_sessions); slot++) {
104 		STAILQ_FOREACH(s, &gotd_notify_sessions[slot], entry) {
105 			if (s->iev.ibuf.fd == fd)
106 				return s;
107 		}
108 	}
109 
110 	return NULL;
111 }
112 
113 static void
114 remove_session(struct gotd_notify_session *session)
115 {
116 	uint64_t slot;
117 
118 	slot = session_hash(session->id) % nitems(gotd_notify_sessions);
119 	STAILQ_REMOVE(&gotd_notify_sessions[slot], session,
120 	    gotd_notify_session, entry);
121 	close(session->iev.ibuf.fd);
122 	free(session);
123 }
124 
125 static uint32_t
126 get_session_id(void)
127 {
128 	int duplicate = 0;
129 	uint32_t id;
130 
131 	do {
132 		id = arc4random();
133 		duplicate = (find_session(id) != NULL);
134 	} while (duplicate || id == 0);
135 
136 	return id;
137 }
138 
139 static void
140 gotd_notify_sighdlr(int sig, short event, void *arg)
141 {
142 	/*
143 	 * Normal signal handler rules don't apply because libevent
144 	 * decouples for us.
145 	 */
146 
147 	switch (sig) {
148 	case SIGHUP:
149 		log_info("%s: ignoring SIGHUP", __func__);
150 		break;
151 	case SIGUSR1:
152 		log_info("%s: ignoring SIGUSR1", __func__);
153 		break;
154 	case SIGTERM:
155 	case SIGINT:
156 		gotd_notify_shutdown();
157 		/* NOTREACHED */
158 		break;
159 	default:
160 		fatalx("unexpected signal");
161 	}
162 }
163 
164 static void
165 run_notification_helper(const char *prog, const char **argv, int fd,
166     const char *user, const char *pass)
167 {
168 	const struct got_error *err = NULL;
169 	pid_t pid;
170 	int child_status;
171 
172 	pid = fork();
173 	if (pid == -1) {
174 		err = got_error_from_errno("fork");
175 		log_warn("%s", err->msg);
176 		return;
177 	} else if (pid == 0) {
178 		signal(SIGQUIT, SIG_DFL);
179 		signal(SIGINT, SIG_DFL);
180 		signal(SIGCHLD, SIG_DFL);
181 
182 		if (dup2(fd, STDIN_FILENO) == -1) {
183 			fprintf(stderr, "%s: dup2: %s\n", getprogname(),
184 			    strerror(errno));
185 			_exit(1);
186 		}
187 
188 		closefrom(STDERR_FILENO + 1);
189 
190 		if (user != NULL && pass != NULL) {
191 			setenv("GOT_NOTIFY_HTTP_USER", user, 1);
192 			setenv("GOT_NOTIFY_HTTP_PASS", pass, 1);
193 		}
194 
195 		if (execv(prog, (char *const *)argv) == -1) {
196 			fprintf(stderr, "%s: exec %s: %s\n", getprogname(),
197 			    prog, strerror(errno));
198 			_exit(1);
199 		}
200 
201 		/* not reached */
202 	}
203 
204 	if (waitpid(pid, &child_status, 0) == -1) {
205 		err = got_error_from_errno("waitpid");
206 		goto done;
207 	}
208 
209 	if (!WIFEXITED(child_status)) {
210 		err = got_error(GOT_ERR_PRIVSEP_DIED);
211 		goto done;
212 	}
213 
214 	if (WEXITSTATUS(child_status) != 0)
215 		err = got_error(GOT_ERR_PRIVSEP_EXIT);
216 done:
217 	if (err)
218 		log_warnx("%s: child %s pid %d: %s", gotd_notify.title,
219 		    prog, pid, err->msg);
220 }
221 
222 static void
223 notify_email(struct gotd_notification_target *target, const char *subject_line,
224     int fd)
225 {
226 	const char *argv[13];
227 	int i = 0;
228 
229 	argv[i++] = GOTD_PATH_PROG_NOTIFY_EMAIL;
230 
231 	argv[i++] = "-f";
232 	if (target->conf.email.sender)
233 		argv[i++] = target->conf.email.sender;
234 	else
235 		argv[i++] = gotd_notify.default_sender;
236 
237 	if (target->conf.email.responder) {
238 		argv[i++] = "-r";
239 		argv[i++] = target->conf.email.responder;
240 	}
241 
242 	if (target->conf.email.hostname) {
243 		argv[i++] = "-h";
244 		argv[i++] = target->conf.email.hostname;
245 	}
246 
247 	if (target->conf.email.port) {
248 		argv[i++] = "-p";
249 		argv[i++] = target->conf.email.port;
250 	}
251 
252 	argv[i++] = "-s";
253 	argv[i++] = subject_line;
254 
255 	argv[i++] = target->conf.email.recipient;
256 
257 	argv[i] = NULL;
258 
259 	run_notification_helper(GOTD_PATH_PROG_NOTIFY_EMAIL, argv, fd,
260 	    NULL, NULL);
261 }
262 
263 static void
264 notify_http(struct gotd_notification_target *target, const char *repo,
265     const char *username, int fd)
266 {
267 	const char *argv[12];
268 	int argc = 0;
269 
270 	argv[argc++] = GOTD_PATH_PROG_NOTIFY_HTTP;
271 	if (target->conf.http.tls)
272 		argv[argc++] = "-c";
273 
274 	argv[argc++] = "-r";
275 	argv[argc++] = repo;
276 	argv[argc++] = "-h";
277 	argv[argc++] = target->conf.http.hostname;
278 	argv[argc++] = "-p";
279 	argv[argc++] = target->conf.http.port;
280 	argv[argc++] = "-u";
281 	argv[argc++] = username;
282 
283 	argv[argc++] = target->conf.http.path;
284 
285 	argv[argc] = NULL;
286 
287 	run_notification_helper(GOTD_PATH_PROG_NOTIFY_HTTP, argv, fd,
288 	    target->conf.http.user, target->conf.http.password);
289 }
290 
291 static const struct got_error *
292 send_notification(struct imsg *imsg, struct gotd_imsgev *iev)
293 {
294 	const struct got_error *err = NULL;
295 	struct gotd_imsg_notify inotify;
296 	size_t datalen;
297 	struct gotd_repo *repo;
298 	struct gotd_notification_target *target;
299 	int fd;
300 	char *username = NULL;
301 
302 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
303 	if (datalen < sizeof(inotify))
304 		return got_error(GOT_ERR_PRIVSEP_LEN);
305 
306 	memcpy(&inotify, imsg->data, sizeof(inotify));
307 	if (datalen != sizeof(inotify) + inotify.username_len)
308 		return got_error(GOT_ERR_PRIVSEP_LEN);
309 
310 	repo = gotd_find_repo_by_name(inotify.repo_name, gotd_notify.repos);
311 	if (repo == NULL)
312 		return got_error(GOT_ERR_PRIVSEP_MSG);
313 
314 	fd = imsg_get_fd(imsg);
315 	if (fd == -1)
316 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
317 
318 	username = strndup(imsg->data + sizeof(inotify), inotify.username_len);
319 	if (username == NULL)
320 		return got_error_from_errno("strndup");
321 
322 	STAILQ_FOREACH(target, &repo->notification_targets, entry) {
323 		if (lseek(fd, 0, SEEK_SET) == -1) {
324 			err = got_error_from_errno("lseek");
325 			goto done;
326 		}
327 		switch (target->type) {
328 		case GOTD_NOTIFICATION_VIA_EMAIL:
329 			notify_email(target, inotify.subject_line, fd);
330 			break;
331 		case GOTD_NOTIFICATION_VIA_HTTP:
332 			notify_http(target, repo->name, username, fd);
333 			break;
334 		}
335 	}
336 
337 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_NOTIFICATION_SENT,
338 	    PROC_NOTIFY, -1, NULL, 0) == -1) {
339 		err = got_error_from_errno("imsg compose NOTIFY");
340 		goto done;
341 	}
342 done:
343 	close(fd);
344 	free(username);
345 	return err;
346 }
347 
348 static void
349 notify_dispatch_session(int fd, short event, void *arg)
350 {
351 	struct gotd_imsgev *iev = arg;
352 	struct imsgbuf *ibuf = &iev->ibuf;
353 	ssize_t n;
354 	int shut = 0;
355 	struct imsg imsg;
356 
357 	if (event & EV_READ) {
358 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
359 			fatal("imsg_read error");
360 		if (n == 0) {
361 			/* Connection closed. */
362 			shut = 1;
363 			goto done;
364 		}
365 	}
366 
367 	if (event & EV_WRITE) {
368 		n = msgbuf_write(&ibuf->w);
369 		if (n == -1 && errno != EAGAIN && errno != EPIPE)
370 			fatal("msgbuf_write");
371 		if (n == 0 || (n == -1 && errno == EPIPE)) {
372 			/* Connection closed. */
373 			shut = 1;
374 			goto done;
375 		}
376 	}
377 
378 	for (;;) {
379 		const struct got_error *err = NULL;
380 
381 		if ((n = imsg_get(ibuf, &imsg)) == -1)
382 			fatal("%s: imsg_get error", __func__);
383 		if (n == 0)	/* No more messages. */
384 			break;
385 
386 		switch (imsg.hdr.type) {
387 		case GOTD_IMSG_NOTIFY:
388 			err = send_notification(&imsg, iev);
389 			break;
390 		default:
391 			log_debug("unexpected imsg %d", imsg.hdr.type);
392 			break;
393 		}
394 		imsg_free(&imsg);
395 
396 		if (err)
397 			log_warnx("%s: %s", __func__, err->msg);
398 	}
399 done:
400 	if (!shut) {
401 		gotd_imsg_event_add(iev);
402 	} else {
403 		struct gotd_notify_session *session;
404 
405 		/* This pipe is dead. Remove its event handler */
406 		event_del(&iev->ev);
407 		imsg_clear(&iev->ibuf);
408 
409 		session = find_session_by_fd(fd);
410 		if (session)
411 			remove_session(session);
412 	}
413 }
414 
415 static const struct got_error *
416 recv_session(struct imsg *imsg)
417 {
418 	struct gotd_notify_session *session;
419 	size_t datalen;
420 	int fd;
421 
422 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
423 	if (datalen != 0)
424 		return got_error(GOT_ERR_PRIVSEP_LEN);
425 
426 	fd = imsg_get_fd(imsg);
427 	if (fd == -1)
428 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
429 
430 	session = calloc(1, sizeof(*session));
431 	if (session == NULL)
432 		return got_error_from_errno("calloc");
433 
434 	session->id = get_session_id();
435 	imsg_init(&session->iev.ibuf, fd);
436 	session->iev.handler = notify_dispatch_session;
437 	session->iev.events = EV_READ;
438 	session->iev.handler_arg = NULL;
439 	event_set(&session->iev.ev, session->iev.ibuf.fd, EV_READ,
440 	    notify_dispatch_session, &session->iev);
441 	gotd_imsg_event_add(&session->iev);
442 	add_session(session);
443 
444 	return NULL;
445 }
446 
447 static void
448 notify_dispatch(int fd, short event, void *arg)
449 {
450 	struct gotd_imsgev *iev = arg;
451 	struct imsgbuf *ibuf = &iev->ibuf;
452 	ssize_t n;
453 	int shut = 0;
454 	struct imsg imsg;
455 
456 	if (event & EV_READ) {
457 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
458 			fatal("imsg_read error");
459 		if (n == 0) {
460 			/* Connection closed. */
461 			shut = 1;
462 			goto done;
463 		}
464 	}
465 
466 	if (event & EV_WRITE) {
467 		n = msgbuf_write(&ibuf->w);
468 		if (n == -1 && errno != EAGAIN)
469 			fatal("msgbuf_write");
470 		if (n == 0) {
471 			/* Connection closed. */
472 			shut = 1;
473 			goto done;
474 		}
475 	}
476 
477 	for (;;) {
478 		const struct got_error *err = NULL;
479 
480 		if ((n = imsg_get(ibuf, &imsg)) == -1)
481 			fatal("%s: imsg_get error", __func__);
482 		if (n == 0)	/* No more messages. */
483 			break;
484 
485 		switch (imsg.hdr.type) {
486 		case GOTD_IMSG_CONNECT_SESSION:
487 			err = recv_session(&imsg);
488 			break;
489 		default:
490 			log_debug("unexpected imsg %d", imsg.hdr.type);
491 			break;
492 		}
493 		imsg_free(&imsg);
494 
495 		if (err)
496 			log_warnx("%s: %s", __func__, err->msg);
497 	}
498 done:
499 	if (!shut) {
500 		gotd_imsg_event_add(iev);
501 	} else {
502 		/* This pipe is dead. Remove its event handler */
503 		event_del(&iev->ev);
504 		event_loopexit(NULL);
505 	}
506 
507 }
508 
509 void
510 notify_main(const char *title, struct gotd_repolist *repos,
511     const char *default_sender)
512 {
513 	const struct got_error *err = NULL;
514 	struct event evsigint, evsigterm, evsighup, evsigusr1;
515 
516 	arc4random_buf(&sessions_hash_key, sizeof(sessions_hash_key));
517 
518 	gotd_notify.title = title;
519 	gotd_notify.repos = repos;
520 	gotd_notify.default_sender = default_sender;
521 	gotd_notify.pid = getpid();
522 
523 	signal_set(&evsigint, SIGINT, gotd_notify_sighdlr, NULL);
524 	signal_set(&evsigterm, SIGTERM, gotd_notify_sighdlr, NULL);
525 	signal_set(&evsighup, SIGHUP, gotd_notify_sighdlr, NULL);
526 	signal_set(&evsigusr1, SIGUSR1, gotd_notify_sighdlr, NULL);
527 	signal(SIGPIPE, SIG_IGN);
528 
529 	signal_add(&evsigint, NULL);
530 	signal_add(&evsigterm, NULL);
531 	signal_add(&evsighup, NULL);
532 	signal_add(&evsigusr1, NULL);
533 
534 	imsg_init(&gotd_notify.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
535 	gotd_notify.parent_iev.handler = notify_dispatch;
536 	gotd_notify.parent_iev.events = EV_READ;
537 	gotd_notify.parent_iev.handler_arg = NULL;
538 	event_set(&gotd_notify.parent_iev.ev, gotd_notify.parent_iev.ibuf.fd,
539 	    EV_READ, notify_dispatch, &gotd_notify.parent_iev);
540 	gotd_imsg_event_add(&gotd_notify.parent_iev);
541 
542 	event_dispatch();
543 
544 	if (err)
545 		log_warnx("%s: %s", title, err->msg);
546 	gotd_notify_shutdown();
547 }
548 
549 void
550 gotd_notify_shutdown(void)
551 {
552 	log_debug("%s: shutting down", gotd_notify.title);
553 	exit(0);
554 }