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