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