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 /*
18  * Handles the data in ~/.telescope
19  *
20  * TODO: add some form of locking on the files
21  */
22 
23 #include <sys/stat.h>
24 
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <limits.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "telescope.h"
34 #include "pages.h"
35 
36 static void		 die(void) __attribute__((__noreturn__));
37 static void		 serve_bookmarks(uint32_t);
38 static void		 send_page(struct imsg *, const uint8_t *, size_t);
39 static void		 handle_get(struct imsg*, size_t);
40 static void		 handle_quit(struct imsg*, size_t);
41 static void		 handle_bookmark_page(struct imsg*, size_t);
42 static void		 handle_save_cert(struct imsg*, size_t);
43 static void		 handle_update_cert(struct imsg*, size_t);
44 static void		 handle_file_open(struct imsg*, size_t);
45 static void		 handle_session_start(struct imsg*, size_t);
46 static void		 handle_session_tab(struct imsg*, size_t);
47 static void		 handle_session_tab_title(struct imsg*, size_t);
48 static void		 handle_session_end(struct imsg*, size_t);
49 static void		 handle_dispatch_imsg(int, short, void*);
50 static int		 fs_send_ui(int, uint32_t, int, const void *, uint16_t);
51 
52 static struct imsgev		*iev_ui;
53 static FILE			*session;
54 
55 static char	lockfile_path[PATH_MAX];
56 static char	bookmark_file[PATH_MAX];
57 static char	known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
58 static char	crashed_file[PATH_MAX];
59 
60 char	session_file[PATH_MAX];
61 
62 static imsg_handlerfn *handlers[] = {
63 	[IMSG_GET] = handle_get,
64 	[IMSG_QUIT] = handle_quit,
65 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
66 	[IMSG_SAVE_CERT] = handle_save_cert,
67 	[IMSG_UPDATE_CERT] = handle_update_cert,
68 	[IMSG_FILE_OPEN] = handle_file_open,
69 	[IMSG_SESSION_START] = handle_session_start,
70 	[IMSG_SESSION_TAB] = handle_session_tab,
71 	[IMSG_SESSION_TAB_TITLE] = handle_session_tab_title,
72 	[IMSG_SESSION_END] = handle_session_end,
73 };
74 
75 static void __attribute__((__noreturn__))
76 die(void)
77 {
78 	abort(); 		/* TODO */
79 }
80 
81 static void
82 serve_bookmarks(uint32_t peerid)
83 {
84 	const char	*t;
85 	char		 buf[BUFSIZ];
86 	size_t		 r;
87 	FILE		*f;
88 
89 	if ((f = fopen(bookmark_file, "r")) == NULL) {
90 		t = "# Bookmarks\n\n"
91 		    "No bookmarks yet!\n"
92 		    "Create ~/.telescope/bookmarks.gmi or use `bookmark-page'.\n";
93 		fs_send_ui(IMSG_BUF, peerid, -1, t, strlen(t));
94 		fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
95 		return;
96 	}
97 
98 	for (;;) {
99 		r = fread(buf, 1, sizeof(buf), f);
100 		fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
101 		if (r != sizeof(buf))
102 			break;
103 	}
104 
105 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
106 
107 	fclose(f);
108 }
109 
110 static void
111 send_page(struct imsg *imsg, const uint8_t *page, size_t len)
112 {
113 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, page, len);
114 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
115 }
116 
117 static void
118 handle_get(struct imsg *imsg, size_t datalen)
119 {
120 	const char	*data, *p;
121 	size_t		 i;
122 	struct page {
123 		const char	*name;
124 		void		(*handle)(uint32_t);
125 		const uint8_t	*data;
126 		size_t		 len;
127 	} pages[] = {
128 		{"about:about",		NULL,	about_about,	about_about_len},
129 		{"about:blank",		NULL,	about_blank,	about_blank_len},
130 		{"about:bookmarks",	serve_bookmarks, 0,	0},
131 		{"about:crash",		NULL,	about_crash,	about_crash_len},
132 		{"about:help",		NULL,	about_help,	about_help_len},
133 		{"about:license",	NULL,	about_license,	about_license_len},
134 		{"about:new",		NULL,	about_new,	about_new_len},
135 	};
136 
137 	data = imsg->data;
138 
139 	if (data[datalen-1] != '\0')
140 		die();
141 
142 	for (i = 0; i < sizeof(pages)/sizeof(pages[0]); ++i) {
143 		if (strcmp(data, pages[i].name) != 0)
144 			continue;
145 
146 		if (pages[i].handle != NULL)
147 			pages[i].handle(imsg->hdr.peerid);
148 		else
149 			send_page(imsg, pages[i].data, pages[i].len);
150 		return;
151 	}
152 
153 	p = "# not found!\n";
154 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
155 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
156 }
157 
158 static void
159 handle_quit(struct imsg *imsg, size_t datalen)
160 {
161 	event_loopbreak();
162 }
163 
164 static void
165 handle_bookmark_page(struct imsg *imsg, size_t datalen)
166 {
167 	char	*data;
168 	int	 res;
169 	FILE	*f;
170 
171 	data = imsg->data;
172 	if (data[datalen-1] != '\0')
173 		die();
174 
175 	if ((f = fopen(bookmark_file, "a")) == NULL) {
176 		res = errno;
177 		goto end;
178 	}
179 	fprintf(f, "=> %s\n", data);
180 	fclose(f);
181 
182 	res = 0;
183 end:
184 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
185 }
186 
187 static void
188 handle_save_cert(struct imsg *imsg, size_t datalen)
189 {
190 	struct tofu_entry	 e;
191 	FILE			*f;
192 	int			 res;
193 
194 	/* TODO: traverse the file to avoid duplications? */
195 
196 	if (datalen != sizeof(e))
197 		die();
198 	memcpy(&e, imsg->data, datalen);
199 
200 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
201 		res = errno;
202 		goto end;
203 	}
204 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
205 	fclose(f);
206 
207 	res = 0;
208 end:
209 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
210 	    &res, sizeof(res));
211 }
212 
213 static void
214 handle_update_cert(struct imsg *imsg, size_t datalen)
215 {
216 	FILE	*tmp, *f;
217 	struct	 tofu_entry entry;
218 	char	 sfn[PATH_MAX], *line = NULL, *t;
219 	size_t	 l, linesize = 0;
220 	ssize_t	 linelen;
221 	int	 fd, e, res = 0;
222 
223 	if (datalen != sizeof(entry))
224 		die();
225 	memcpy(&entry, imsg->data, datalen);
226 
227 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
228 	if ((fd = mkstemp(sfn)) == -1 ||
229 	    (tmp = fdopen(fd, "w")) == NULL) {
230 		if (fd != -1) {
231 			unlink(sfn);
232 			close(fd);
233 		}
234 		res = 0;
235 		goto end;
236 	}
237 
238 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
239 		unlink(sfn);
240 		fclose(tmp);
241                 res = 0;
242 		goto end;
243 	}
244 
245 	l = strlen(entry.domain);
246 	while ((linelen = getline(&line, &linesize, f)) != -1) {
247 		if ((t = strstr(line, entry.domain)) != NULL &&
248 		    (line[l] == ' ' || line[l] == '\t'))
249 			continue;
250 		/* line has a trailing \n */
251 		fprintf(tmp, "%s", line);
252 	}
253 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
254 
255 	free(line);
256 	e = ferror(tmp);
257 
258 	fclose(tmp);
259 	fclose(f);
260 
261 	if (e) {
262 		unlink(sfn);
263 		res = 0;
264 		goto end;
265 	}
266 
267 	res = rename(sfn, known_hosts_file) != -1;
268 
269 end:
270 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
271 	    &res, sizeof(res));
272 }
273 
274 static void
275 handle_file_open(struct imsg *imsg, size_t datalen)
276 {
277 	char	*path, *e;
278 	int	 fd;
279 
280 	path = imsg->data;
281 	if (path[datalen-1] != '\0')
282 		die();
283 
284 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
285 		e = strerror(errno);
286 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
287 		    e, strlen(e)+1);
288 	} else
289 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
290 		    NULL, 0);
291 }
292 
293 static void
294 handle_session_start(struct imsg *imsg, size_t datalen)
295 {
296 	if (datalen != 0)
297 		die();
298 
299 	if ((session = fopen(session_file, "w")) == NULL)
300 		die();
301 }
302 
303 static void
304 handle_session_tab(struct imsg *imsg, size_t datalen)
305 {
306 	char		*url;
307 	uint32_t	 flags;
308 
309 	if (session == NULL)
310 		die();
311 
312 	flags = imsg->hdr.peerid;
313 	url = imsg->data;
314 	if (datalen == 0 || url[datalen-1] != '\0')
315 		die();
316 	fprintf(session, "%s", url);
317 
318 	if (flags & TAB_CURRENT)
319 		fprintf(session, " current ");
320 	else
321 		fprintf(session, " - ");
322 }
323 
324 static void
325 handle_session_tab_title(struct imsg *imsg, size_t datalen)
326 {
327 	const char	*title;
328 
329 	title = imsg->data;
330 	if (title == NULL) {
331 		datalen = 1;
332 		title = "";
333 	}
334 
335 	if (title[datalen-1] != '\0')
336 		die();
337 
338 	fprintf(session, "%s\n", title);
339 }
340 
341 static void
342 handle_session_end(struct imsg *imsg, size_t datalen)
343 {
344 	if (session == NULL)
345 		die();
346 	fclose(session);
347 	session = NULL;
348 }
349 
350 static void
351 handle_dispatch_imsg(int fd, short ev, void *d)
352 {
353 	struct imsgev	*iev = d;
354 	int		 e;
355 
356 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1) {
357 		/*
358 		 * This should leave a ~/.telescope/crashed file to
359 		 * trigger about:crash on next run.  Unfortunately, if
360 		 * the main process dies the fs sticks around and
361 		 * doesn't notice that the fd was closed.  Why EV_READ
362 		 * is not triggered when a fd is closed on the other end?
363 		 */
364 		e = errno;
365 		if ((fd = open(crashed_file, O_CREAT|O_TRUNC|O_WRONLY, 0600))
366 		    == -1)
367 			err(1, "open");
368 		close(fd);
369 		errx(1, "connection closed: %s", strerror(e));
370 	}
371 }
372 
373 static int
374 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
375     uint16_t datalen)
376 {
377 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
378 	    data, datalen);
379 }
380 
381 int
382 fs_init(void)
383 {
384 	char	dir[PATH_MAX];
385 
386 	strlcpy(dir, getenv("HOME"), sizeof(dir));
387 	strlcat(dir, "/.telescope", sizeof(dir));
388 	mkdir(dir, 0700);
389 
390 	strlcpy(lockfile_path, getenv("HOME"), sizeof(lockfile_path));
391 	strlcat(lockfile_path, "/.telescope/lock", sizeof(lockfile_path));
392 
393 	strlcpy(bookmark_file, getenv("HOME"), sizeof(bookmark_file));
394 	strlcat(bookmark_file, "/.telescope/bookmarks.gmi", sizeof(bookmark_file));
395 
396 	strlcpy(known_hosts_file, getenv("HOME"), sizeof(known_hosts_file));
397 	strlcat(known_hosts_file, "/.telescope/known_hosts", sizeof(known_hosts_file));
398 
399 	strlcpy(known_hosts_tmp, getenv("HOME"), sizeof(known_hosts_tmp));
400 	strlcat(known_hosts_tmp, "/.telescope/known_hosts.tmp.XXXXXXXXXX",
401 	    sizeof(known_hosts_file));
402 
403 	strlcpy(session_file, getenv("HOME"), sizeof(session_file));
404 	strlcat(session_file, "/.telescope/session", sizeof(session_file));
405 
406 	strlcpy(crashed_file, getenv("HOME"), sizeof(crashed_file));
407 	strlcat(crashed_file, "/.telescope/crashed", sizeof(crashed_file));
408 
409 	return 1;
410 }
411 
412 int
413 fs_main(void)
414 {
415 	setproctitle("fs");
416 
417 	fs_init();
418 
419 	event_init();
420 
421 	/* Setup pipe and event handler to the main process */
422 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
423 		die();
424 	imsg_init(&iev_ui->ibuf, 3);
425 	iev_ui->handler = handle_dispatch_imsg;
426 	iev_ui->events = EV_READ;
427 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
428 	    iev_ui->handler, iev_ui);
429 	event_add(&iev_ui->ev, NULL);
430 
431 	sandbox_fs_process();
432 
433 	event_dispatch();
434 	return 0;
435 }
436 
437 
438 
439 int
440 last_time_crashed(void)
441 {
442 	int fd;
443 
444 	if ((fd = open(crashed_file, O_RDONLY)) == -1)
445 		return 0;
446 
447 	close(fd);
448 	unlink(crashed_file);
449 	return 1;
450 }
451 
452 int
453 lock_session(void)
454 {
455 	struct flock	lock;
456 	int		fd;
457 
458 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
459 		return -1;
460 
461 	lock.l_start = 0;
462 	lock.l_len = 0;
463 	lock.l_type = F_WRLCK;
464 	lock.l_whence = SEEK_SET;
465 
466 	if (fcntl(fd, F_SETLK, &lock) == -1) {
467 		close(fd);
468 		return -1;
469 	}
470 
471 	return fd;
472 }
473 
474 static int
475 parse_khost_line(char *line, char *tmp[3])
476 {
477 	char **ap;
478 
479 	for (ap = tmp; ap < &tmp[3] &&
480 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
481 		if (**ap != '\0')
482 			ap++;
483 	}
484 
485 	return ap == &tmp[3] && *line == '\0';
486 }
487 
488 int
489 load_certs(struct ohash *h)
490 {
491 	char		*tmp[3], *line = NULL;
492 	const char	*errstr;
493 	size_t		 lineno = 0, linesize = 0;
494 	ssize_t		 linelen;
495 	FILE		*f;
496 	struct tofu_entry *e;
497 
498 	if ((f = fopen(known_hosts_file, "r")) == NULL)
499 		return 0;
500 
501 	while ((linelen = getline(&line, &linesize, f)) != -1) {
502 		if ((e = calloc(1, sizeof(*e))) == NULL)
503 			abort();
504 
505 		lineno++;
506 
507 		if (parse_khost_line(line, tmp)) {
508 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
509 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
510 
511 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
512 			if (errstr != NULL)
513 				errx(1, "%s:%zu verification for %s is %s: %s",
514 				    known_hosts_file, lineno,
515 				    e->domain, errstr, tmp[2]);
516 			tofu_add(h, e);
517 		} else {
518 			warnx("%s:%zu invalid entry",
519 			    known_hosts_file, lineno);
520 			free(e);
521 		}
522 	}
523 
524 	free(line);
525 	return ferror(f);
526 }
527