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 "telescope.h"
24 
25 #include <sys/stat.h>
26 
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <limits.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 static void		 die(void) __attribute__((__noreturn__));
36 static void		 serve_bookmarks(uint32_t);
37 static void		 handle_get(struct imsg*, size_t);
38 static void		 handle_quit(struct imsg*, size_t);
39 static void		 handle_bookmark_page(struct imsg*, size_t);
40 static void		 handle_save_cert(struct imsg*, size_t);
41 static void		 handle_update_cert(struct imsg*, size_t);
42 static void		 handle_file_open(struct imsg*, size_t);
43 static void		 handle_session_start(struct imsg*, size_t);
44 static void		 handle_session_tab(struct imsg*, size_t);
45 static void		 handle_session_end(struct imsg*, size_t);
46 static void		 handle_dispatch_imsg(int, short, void*);
47 
48 static struct event		 imsgev;
49 static struct imsgbuf		*ibuf;
50 
51 static FILE			*session;
52 
53 static char	bookmark_file[PATH_MAX];
54 static char	known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
55 static char	session_file[PATH_MAX];
56 
57 static imsg_handlerfn *handlers[] = {
58 	[IMSG_GET] = handle_get,
59 	[IMSG_QUIT] = handle_quit,
60 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
61 	[IMSG_SAVE_CERT] = handle_save_cert,
62 	[IMSG_UPDATE_CERT] = handle_update_cert,
63 	[IMSG_FILE_OPEN] = handle_file_open,
64 	[IMSG_SESSION_START] = handle_session_start,
65 	[IMSG_SESSION_TAB] = handle_session_tab,
66 	[IMSG_SESSION_END] = handle_session_end,
67 };
68 
69 static void __attribute__((__noreturn__))
70 die(void)
71 {
72 	abort(); 		/* TODO */
73 }
74 
75 static void
76 serve_bookmarks(uint32_t peerid)
77 {
78 	const char	*t;
79 	char		 buf[BUFSIZ];
80 	size_t		 r;
81 	FILE		*f;
82 
83 	if ((f = fopen(bookmark_file, "r")) == NULL) {
84 		t = "# Bookmarks\n\n"
85 		    "No bookmarks yet!\n"
86 		    "Create ~/.telescope/bookmarks.gmi or use `bookmark-page'.\n";
87 		imsg_compose(ibuf, IMSG_BUF, peerid, 0, -1, t, strlen(t));
88 		imsg_compose(ibuf, IMSG_EOF, peerid, 0, -1, NULL, 0);
89 		imsg_flush(ibuf);
90 		return;
91 	}
92 
93 	for (;;) {
94 		r = fread(buf, 1, sizeof(buf), f);
95 		imsg_compose(ibuf, IMSG_BUF, peerid, 0, -1, buf, r);
96 		imsg_flush(ibuf);
97 		if (r != sizeof(buf))
98 			break;
99 	}
100 
101 	imsg_compose(ibuf, IMSG_EOF, peerid, 0, -1, NULL, 0);
102 	imsg_flush(ibuf);
103 
104 	fclose(f);
105 }
106 
107 static void
108 handle_get(struct imsg *imsg, size_t datalen)
109 {
110 	char		*data;
111 	const char	*p;
112 
113 	data = imsg->data;
114 
115 	if (data[datalen-1] != '\0')
116 		die();
117 
118 	if (!strcmp(data, "about:new")) {
119 		imsg_compose(ibuf, IMSG_BUF, imsg->hdr.peerid, 0, -1,
120 		    about_new, strlen(about_new));
121 		imsg_compose(ibuf, IMSG_EOF, imsg->hdr.peerid, 0, -1, NULL, 0);
122 		imsg_flush(ibuf);
123 	} else if (!strcmp(data, "about:bookmarks")) {
124 		serve_bookmarks(imsg->hdr.peerid);
125 	} else {
126 		p = "# not found!\n";
127 		imsg_compose(ibuf, IMSG_BUF, imsg->hdr.peerid, 0, -1, p, strlen(p));
128 		imsg_compose(ibuf, IMSG_EOF, imsg->hdr.peerid, 0, -1, NULL, 0);
129 		imsg_flush(ibuf);
130 	}
131 }
132 
133 static void
134 handle_quit(struct imsg *imsg, size_t datalen)
135 {
136 	event_loopbreak();
137 }
138 
139 static void
140 handle_bookmark_page(struct imsg *imsg, size_t datalen)
141 {
142 	char	*data;
143 	int	 res;
144 	FILE	*f;
145 
146 	data = imsg->data;
147 	if (data[datalen-1] != '\0')
148 		die();
149 
150 	if ((f = fopen(bookmark_file, "a")) == NULL) {
151 		res = errno;
152 		goto end;
153 	}
154 	fprintf(f, "=> %s\n", data);
155 	fclose(f);
156 
157 	res = 0;
158 end:
159 	imsg_compose(ibuf, IMSG_BOOKMARK_OK, 0, 0, -1, &res, sizeof(res));
160 	imsg_flush(ibuf);
161 }
162 
163 static void
164 handle_save_cert(struct imsg *imsg, size_t datalen)
165 {
166 	struct tofu_entry	 e;
167 	FILE			*f;
168 	int			 res;
169 
170 	/* TODO: traverse the file to avoid duplications? */
171 
172 	if (datalen != sizeof(e))
173 		die();
174 	memcpy(&e, imsg->data, datalen);
175 
176 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
177 		res = errno;
178 		goto end;
179 	}
180 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
181 	fclose(f);
182 
183 	res = 0;
184 end:
185 	imsg_compose(ibuf, IMSG_SAVE_CERT_OK, imsg->hdr.peerid, 0, -1,
186 	    &res, sizeof(res));
187 	imsg_flush(ibuf);
188 }
189 
190 static void
191 handle_update_cert(struct imsg *imsg, size_t datalen)
192 {
193 	FILE	*tmp, *f;
194 	struct	 tofu_entry entry;
195 	char	 sfn[PATH_MAX], *line = NULL, *t;
196 	size_t	 l, linesize = 0;
197 	ssize_t	 linelen;
198 	int	 fd, e, res = 0;
199 
200 	if (datalen != sizeof(entry))
201 		die();
202 	memcpy(&entry, imsg->data, datalen);
203 
204 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
205 	if ((fd = mkstemp(sfn)) == -1 ||
206 	    (tmp = fdopen(fd, "w")) == NULL) {
207 		if (fd != -1) {
208 			unlink(sfn);
209 			close(fd);
210 		}
211 		res = 0;
212 		goto end;
213 	}
214 
215 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
216 		unlink(sfn);
217 		fclose(tmp);
218                 res = 0;
219 		goto end;
220 	}
221 
222 	l = strlen(entry.domain);
223 	while ((linelen = getline(&line, &linesize, f)) != -1) {
224 		if ((t = strstr(line, entry.domain)) != NULL &&
225 		    (line[l] == ' ' || line[l] == '\t'))
226 			continue;
227 		/* line has a trailing \n */
228 		fprintf(tmp, "%s", line);
229 	}
230 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
231 
232 	free(line);
233 	e = ferror(tmp);
234 
235 	fclose(tmp);
236 	fclose(f);
237 
238 	if (e) {
239 		unlink(sfn);
240 		res = 0;
241 		goto end;
242 	}
243 
244 	res = rename(sfn, known_hosts_file) != -1;
245 
246 end:
247 	imsg_compose(ibuf, IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, 0, -1,
248 	    &res, sizeof(res));
249 	imsg_flush(ibuf);
250 }
251 
252 static void
253 handle_file_open(struct imsg *imsg, size_t datalen)
254 {
255 	char	*path, *e;
256 	int	 fd;
257 
258 	path = imsg->data;
259 	if (path[datalen-1] != '\0')
260 		die();
261 
262 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
263 		e = strerror(errno);
264 		imsg_compose(ibuf, IMSG_FILE_OPENED, imsg->hdr.peerid, 0, -1,
265 		    e, strlen(e)+1);
266 	} else
267 		imsg_compose(ibuf, IMSG_FILE_OPENED, imsg->hdr.peerid, 0, fd,
268 		    NULL, 0);
269 
270 	imsg_flush(ibuf);
271 }
272 
273 static void
274 handle_session_start(struct imsg *imsg, size_t datalen)
275 {
276 	if (datalen != 0)
277 		die();
278 
279 	if ((session = fopen(session_file, "w")) == NULL)
280 		die();
281 }
282 
283 static void
284 handle_session_tab(struct imsg *imsg, size_t datalen)
285 {
286 	if (session == NULL)
287 		die();
288 
289 	if (datalen == 0)
290 		die();
291 
292 	/* skip the NUL-terminator */
293         fwrite(imsg->data, 1, datalen-1, session);
294 
295 	fprintf(session, "\n");
296 }
297 
298 static void
299 handle_session_end(struct imsg *imsg, size_t datalen)
300 {
301 	if (session == NULL)
302 		die();
303 	fclose(session);
304 	session = NULL;
305 }
306 
307 static void
308 handle_dispatch_imsg(int fd, short ev, void *d)
309 {
310 	struct imsgbuf	*ibuf = d;
311 	dispatch_imsg(ibuf, handlers, sizeof(handlers));
312 }
313 
314 int
315 fs_init(void)
316 {
317 	char	dir[PATH_MAX];
318 
319 	strlcpy(dir, getenv("HOME"), sizeof(dir));
320 	strlcat(dir, "/.telescope", sizeof(dir));
321 	mkdir(dir, 0700);
322 
323 	strlcpy(bookmark_file, getenv("HOME"), sizeof(bookmark_file));
324 	strlcat(bookmark_file, "/.telescope/bookmarks.gmi", sizeof(bookmark_file));
325 
326 	strlcpy(known_hosts_file, getenv("HOME"), sizeof(known_hosts_file));
327 	strlcat(known_hosts_file, "/.telescope/known_hosts", sizeof(known_hosts_file));
328 
329 	strlcpy(known_hosts_tmp, getenv("HOME"), sizeof(known_hosts_tmp));
330 	strlcat(known_hosts_tmp, "/.telescope/known_hosts.tmp.XXXXXXXXXX",
331 	    sizeof(known_hosts_file));
332 
333 	strlcpy(session_file, getenv("HOME"), sizeof(session_file));
334 	strlcat(session_file, "/.telescope/session", sizeof(session_file));
335 
336 	return 1;
337 }
338 
339 int
340 fs_main(struct imsgbuf *b)
341 {
342 	ibuf = b;
343 
344 	event_init();
345 
346 	event_set(&imsgev, ibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, ibuf);
347 	event_add(&imsgev, NULL);
348 
349 	sandbox_fs_process();
350 
351 	event_dispatch();
352 	return 0;
353 }
354 
355 
356 
357 static int
358 parse_khost_line(char *line, char *tmp[3])
359 {
360 	char **ap;
361 
362 	for (ap = tmp; ap < &tmp[3] &&
363 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
364 		if (**ap != '\0')
365 			ap++;
366 	}
367 
368 	return ap == &tmp[3] && *line == '\0';
369 }
370 
371 int
372 load_certs(struct ohash *h)
373 {
374 	char		*tmp[3], *line = NULL;
375 	const char	*errstr;
376 	size_t		 lineno = 0, linesize = 0;
377 	ssize_t		 linelen;
378 	FILE		*f;
379 	struct tofu_entry *e;
380 
381 	if ((f = fopen(known_hosts_file, "r")) == NULL)
382 		return 0;
383 
384 	while ((linelen = getline(&line, &linesize, f)) != -1) {
385 		if ((e = calloc(1, sizeof(*e))) == NULL)
386 			abort();
387 
388 		lineno++;
389 
390 		if (parse_khost_line(line, tmp)) {
391 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
392 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
393 
394 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
395 			if (errstr != NULL)
396 				errx(1, "%s:%zu verification for %s is %s: %s",
397 				    known_hosts_file, lineno,
398 				    e->domain, errstr, tmp[2]);
399 			tofu_add(h, e);
400 		} else {
401 			warnx("%s:%zu invalid entry",
402 			    known_hosts_file, lineno);
403 			free(e);
404 		}
405 	}
406 
407 	free(line);
408 	return ferror(f);
409 }
410 
411 int
412 load_last_session(void (*cb)(const char*))
413 {
414 	char	*nl, *line = NULL;
415 	int	 e;
416 	size_t	 linesize = 0;
417 	ssize_t	 linelen;
418 	FILE	*session;
419 
420 	if ((session = fopen(session_file, "r")) == NULL)
421 		return 0;
422 
423 	while ((linelen = getline(&line, &linesize, session)) != -1) {
424                 if ((nl = strchr(line, '\n')) != NULL)
425 			*nl = '\0';
426 		cb(line);
427 	}
428 
429 	free(line);
430 	e = ferror(session);
431 	fclose(session);
432 
433 	return !e;
434 }