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Date:: Thu Mar 25 14:32:08 2021 UTC
Message:: add y-or-n-p; ask user when encountering invalid certs
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1 #include "telescope.h"
2 
3 #include <sys/socket.h>
4 
5 #include <errno.h>
6 #include <signal.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <unistd.h>
11 
12 struct event		 netev, fsev;
13 struct tabshead		 tabshead;
14 
15 /* the first is also the fallback one */
16 static struct proto protos[] = {
17 	{ "gemini:",	load_gemini_url },
18 	{ "about:",	load_about_url },
19 	{ NULL, NULL },
20 };
21 
22 static struct imsgbuf	*netibuf, *fsibuf;
23 
24 static void		 die(void) __attribute__((__noreturn__));
25 static struct tab	*tab_by_id(uint32_t);
26 static void		 handle_imsg_err(struct imsg*, size_t);
27 static void		 handle_imsg_check_cert(struct imsg*, size_t);
28 static void		 handle_check_cert_user_choice(int, unsigned int);
29 static void		 handle_imsg_got_code(struct imsg*, size_t);
30 static void		 handle_imsg_got_meta(struct imsg*, size_t);
31 static void		 handle_imsg_buf(struct imsg*, size_t);
32 static void		 handle_imsg_eof(struct imsg*, size_t);
33 static void		 handle_imsg_bookmark_ok(struct imsg*, size_t);
34 static void		 handle_imsg_save_cert_ok(struct imsg*, size_t);
35 static void		 handle_dispatch_imsg(int, short, void*);
36 static void		 load_page_from_str(struct tab*, const char*);
37 static void		 do_load_url(struct tab*, const char*);
38 
39 static imsg_handlerfn *handlers[] = {
40 	[IMSG_ERR] = handle_imsg_err,
41 	[IMSG_CHECK_CERT] = handle_imsg_check_cert,
42 	[IMSG_GOT_CODE] = handle_imsg_got_code,
43 	[IMSG_GOT_META] = handle_imsg_got_meta,
44 	[IMSG_BUF] = handle_imsg_buf,
45 	[IMSG_EOF] = handle_imsg_eof,
46 	[IMSG_BOOKMARK_OK] = handle_imsg_bookmark_ok,
47 	[IMSG_SAVE_CERT_OK] = handle_imsg_save_cert_ok,
48 };
49 
50 static struct ohash	certs;
51 
52 static void __attribute__((__noreturn__))
53 die(void)
54 {
55 	abort(); 		/* TODO */
56 }
57 
58 static struct tab *
59 tab_by_id(uint32_t id)
60 {
61 	struct tab *t;
62 
63 	TAILQ_FOREACH(t, &tabshead, tabs) {
64 		if (t->id == id)
65 			return t;
66 	}
67 
68 	die();
69 }
70 
71 static void
72 handle_imsg_err(struct imsg *imsg, size_t datalen)
73 {
74 	struct tab	*tab;
75 	char		*page;
76 
77 	tab = tab_by_id(imsg->hdr.peerid);
78 
79 	page = imsg->data;
80 	page[datalen-1] = '\0';
81 
82 	if (asprintf(&page, "# Error loading %s\n\n> %s\n",
83 	    tab->hist_cur->h, page) == -1)
84 		die();
85 	load_page_from_str(tab, page);
86 	free(page);
87 }
88 
89 static void
90 handle_imsg_check_cert(struct imsg *imsg, size_t datalen)
91 {
92 	const char		*hash;
93 	int			 tofu_res;
94 	struct tofu_entry	*e;
95 	struct tab		*tab;
96 
97 	hash = imsg->data;
98 	if (hash[datalen-1] != '\0')
99 		abort();
100 
101 	tab = tab_by_id(imsg->hdr.peerid);
102 
103 	if ((e = telescope_lookup_tofu(&certs, tab->url.host)) == NULL) {
104 		/* TODO: an update in libressl/libretls changed
105 		 * significantly.  Find a better approach at storing
106 		 * the certs! */
107 		if (datalen > sizeof(e->hash))
108 			abort();
109 
110 		tofu_res = 1;	/* trust on first use */
111 		if ((e = calloc(1, sizeof(*e))) == NULL)
112 			abort();
113 		strlcpy(e->domain, tab->url.host, sizeof(e->domain));
114 		strlcpy(e->hash, hash, sizeof(e->hash));
115 		telescope_ohash_insert(&certs, e);
116 		imsg_compose(fsibuf, IMSG_SAVE_CERT, tab->id, 0, -1,
117 		    e, sizeof(*e));
118 		imsg_flush(fsibuf);
119 	} else
120 		tofu_res = !strcmp(hash, e->hash);
121 
122 	if (tofu_res) {
123 		tab->trust = e->verified ? TS_VERIFIED : TS_TRUSTED;
124 		imsg_compose(netibuf, IMSG_CERT_STATUS, imsg->hdr.peerid, 0, -1,
125 		    &tofu_res, sizeof(tofu_res));
126 		imsg_flush(netibuf);
127 	} else {
128 		tab->trust = TS_UNTRUSTED;
129 		load_page_from_str(tab, "# Certificate mismatch\n");
130 		ui_yornp("Certificate mismatch.  Proceed?",
131 		    handle_check_cert_user_choice);
132 	}
133 }
134 
135 static void
136 handle_check_cert_user_choice(int accept, unsigned int tabid)
137 {
138 	imsg_compose(netibuf, IMSG_CERT_STATUS, tabid, 0, -1,
139 	    &accept, sizeof(accept));
140 	imsg_flush(netibuf);
141 }
142 
143 static inline int
144 normalize_code(int n)
145 {
146 	if (n < 20) {
147 		if (n == 10 || n == 11)
148 			return n;
149 		return 10;
150 	} else if (n < 30) {
151 		return 20;
152 	} else if (n < 40) {
153 		if (n == 30 || n == 31)
154 			return n;
155 		return 30;
156 	} else if (n < 50) {
157 		if (n <= 44)
158 			return n;
159 		return 40;
160 	} else if (n < 60) {
161 		if (n <= 53 || n == 59)
162 			return n;
163 		return 50;
164 	} else if (n < 70) {
165 		if (n <= 62)
166 			return n;
167 		return 60;
168 	} else
169 		return MALFORMED_RESPONSE;
170 }
171 
172 static void
173 handle_imsg_got_code(struct imsg *imsg, size_t datalen)
174 {
175 	struct tab	*tab;
176 
177 	tab = tab_by_id(imsg->hdr.peerid);
178 
179 	if (sizeof(tab->code) != datalen)
180 		die();
181 
182 	memcpy(&tab->code, imsg->data, sizeof(tab->code));
183 	tab->code = normalize_code(tab->code);
184 	if (tab->code != 30 && tab->code != 31)
185 		tab->redirect_count = 0;
186 }
187 
188 static void
189 handle_imsg_got_meta(struct imsg *imsg, size_t datalen)
190 {
191 	struct tab	*tab;
192 
193 	tab = tab_by_id(imsg->hdr.peerid);
194 
195 	if (sizeof(tab->meta) <= datalen)
196 		die();
197 
198 	memcpy(tab->meta, imsg->data, datalen);
199 
200 	if (tab->code < 10) {	/* internal errors */
201 		load_page_from_str(tab, err_pages[tab->code]);
202 	} else if (tab->code < 20) {	/* 1x */
203 		load_page_from_str(tab, err_pages[tab->code]);
204 		ui_require_input(tab, tab->code == 11);
205 	} else if (tab->code == 20) {
206 		if (setup_parser_for(tab)) {
207 			imsg_compose(netibuf, IMSG_PROCEED, tab->id, 0, -1, NULL, 0);
208 			imsg_flush(netibuf);
209 		} else {
210 			load_page_from_str(tab, err_pages[UNKNOWN_TYPE_OR_CSET]);
211 		}
212 	} else if (tab->code < 40) { /* 3x */
213 		tab->redirect_count++;
214 
215 		/* TODO: make customizable? */
216 		if (tab->redirect_count > 5) {
217 			load_page_from_str(tab,
218 			    err_pages[TOO_MUCH_REDIRECTS]);
219 		} else
220 			do_load_url(tab, tab->meta);
221 	} else { /* 4x, 5x & 6x */
222 		load_page_from_str(tab, err_pages[tab->code]);
223 	}
224 }
225 
226 static void
227 handle_imsg_buf(struct imsg *imsg, size_t datalen)
228 {
229 	struct tab	*tab;
230 
231 	tab = tab_by_id(imsg->hdr.peerid);
232 
233 	if (!tab->window.page.parse(&tab->window.page, imsg->data, datalen))
234 		die();
235 
236 	ui_on_tab_refresh(tab);
237 }
238 
239 static void
240 handle_imsg_eof(struct imsg *imsg, size_t datalen)
241 {
242 	struct tab	*tab;
243 
244 	tab = tab_by_id(imsg->hdr.peerid);
245 	if (!tab->window.page.free(&tab->window.page))
246 		die();
247 
248 	ui_on_tab_refresh(tab);
249 	ui_on_tab_loaded(tab);
250 }
251 
252 static void
253 handle_imsg_bookmark_ok(struct imsg *imsg, size_t datalen)
254 {
255 	int res;
256 
257 	if (datalen != sizeof(res))
258 		die();
259 
260 	memcpy(&res, imsg->data, sizeof(res));
261 	if (res == 0)
262 		ui_notify("Added to bookmarks!");
263 	else
264 		ui_notify("Failed to add to bookmarks: %s",
265 		    strerror(res));
266 }
267 
268 static void
269 handle_imsg_save_cert_ok(struct imsg *imsg, size_t datalen)
270 {
271 	int res;
272 
273 	if (datalen != sizeof(res))
274 		die();
275 	memcpy(&res, imsg->data, datalen);
276 	if (res != 0)
277 		ui_notify("Failed to save the cert for: %s",
278 		    strerror(res));
279 }
280 
281 static void
282 handle_dispatch_imsg(int fd, short ev, void *d)
283 {
284 	struct imsgbuf	*ibuf = d;
285 	dispatch_imsg(ibuf, handlers, sizeof(handlers));
286 }
287 
288 static void
289 load_page_from_str(struct tab *tab, const char *page)
290 {
291 	gemtext_initparser(&tab->window.page);
292 	if (!tab->window.page.parse(&tab->window.page, page, strlen(page)))
293 		die();
294 	if (!tab->window.page.free(&tab->window.page))
295 		die();
296 	ui_on_tab_refresh(tab);
297 	ui_on_tab_loaded(tab);
298 }
299 
300 void
301 load_about_url(struct tab *tab, const char *url)
302 {
303 	char	*m;
304 	size_t	 len;
305 
306 	tab->trust = TS_VERIFIED;
307 
308 	memset(&tab->url, 0, sizeof(tab->url));
309 
310 	m = strchr(url, ':');
311 	strlcpy(tab->url.scheme, "about", sizeof(tab->url.scheme));
312 	strlcpy(tab->url.path, m+1, sizeof(tab->url.path));
313 
314 	len = sizeof(tab->hist_cur->h)-1;
315 	strlcpy(tab->hist_cur->h, url, len);
316 
317 	gemtext_initparser(&tab->window.page);
318 
319 	imsg_compose(fsibuf, IMSG_GET, tab->id, 0, -1,
320 	    tab->hist_cur->h, len+1);
321 	imsg_flush(fsibuf);
322 }
323 
324 void
325 load_gemini_url(struct tab *tab, const char *url)
326 {
327 	const char	*err;
328 	char		*p;
329 	size_t		 len;
330 
331 	len = sizeof(tab->hist_cur->h)-1;
332 
333 	if (has_prefix(url, "gemini:")) {
334 		if (!url_parse(url, &tab->url, &err))
335 			goto err;
336 	} else {
337 		if (!url_resolve_from(&tab->url, url, &err))
338 			goto err;
339 	}
340 
341 	url_unparse(&tab->url, tab->hist_cur->h, len);
342 	imsg_compose(netibuf, IMSG_GET, tab->id, 0, -1,
343 	    tab->hist_cur->h, len+1);
344 	imsg_flush(netibuf);
345 	return;
346 
347 err:
348 	if (asprintf(&p, "#error loading %s\n>%s\n",
349 	    url, err) == -1)
350 		die();
351 	strlcpy(tab->hist_cur->h, url, len);
352 	load_page_from_str(tab, p);
353 	free(p);
354 }
355 
356 static void
357 do_load_url(struct tab *tab, const char *url)
358 {
359 	struct proto *p;
360 
361 	tab->trust = TS_UNKNOWN;
362 
363 	for (p = protos; p->schema != NULL; ++p) {
364 		if (has_prefix(url, p->schema)) {
365 			p->loadfn(tab, url);
366 			return;
367 		}
368 	}
369 
370 	protos[0].loadfn(tab, url);
371 }
372 
373 void
374 load_url(struct tab *tab, const char *url)
375 {
376 	if (tab->hist_cur != NULL)
377 		hist_clear_forward(&tab->hist, TAILQ_NEXT(tab->hist_cur, entries));
378 
379 	if ((tab->hist_cur = calloc(1, sizeof(*tab->hist_cur))) == NULL) {
380 		event_loopbreak();
381 		return;
382 	}
383 	hist_push(&tab->hist, tab->hist_cur);
384 	do_load_url(tab, url);
385 }
386 
387 int
388 load_previous_page(struct tab *tab)
389 {
390 	struct hist	*h;
391 
392 	if ((h = TAILQ_PREV(tab->hist_cur, mhisthead, entries)) == NULL)
393 		return 0;
394 	tab->hist_cur = h;
395 	do_load_url(tab, h->h);
396 	return 1;
397 }
398 
399 int
400 load_next_page(struct tab *tab)
401 {
402 	struct hist	*h;
403 
404 	if ((h = TAILQ_NEXT(tab->hist_cur, entries)) == NULL)
405 		return 0;
406 	tab->hist_cur = h;
407 	do_load_url(tab, h->h);
408 	return 1;
409 }
410 
411 void
412 stop_tab(struct tab *tab)
413 {
414 	imsg_compose(netibuf, IMSG_STOP, tab->id, 0, -1, NULL, 0);
415 	imsg_flush(netibuf);
416 }
417 
418 void
419 add_to_bookmarks(const char *str)
420 {
421 	imsg_compose(fsibuf, IMSG_BOOKMARK_PAGE, 0, 0, -1, str, strlen(str)+1);
422 	imsg_flush(fsibuf);
423 }
424 
425 int
426 main(int argc, char * const *argv)
427 {
428 	struct imsgbuf	network_ibuf, fs_ibuf;
429 	int		net_fds[2], fs_fds[2];
430 	pid_t		pid;
431 
432 	pid = getpid();
433 
434 	signal(SIGCHLD, SIG_IGN);
435 
436 	/* initialize part of the fs layer.  Before starting the UI
437 	 * and dropping the priviledges we need to read some stuff. */
438 	fs_init();
439 
440 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, fs_fds) == -1)
441 		err(1, "socketpair");
442 
443 	switch (fork()) {
444 	case -1:
445 		err(1, "fork");
446 	case 0:
447 		/* child */
448 		setproctitle("(%d) fs", pid);
449 		close(fs_fds[0]);
450 		imsg_init(&fs_ibuf, fs_fds[1]);
451 		exit(fs_main(&fs_ibuf));
452 	default:
453 		close(fs_fds[1]);
454 		imsg_init(&fs_ibuf, fs_fds[0]);
455 		fsibuf = &fs_ibuf;
456 	}
457 
458 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, net_fds) == -1)
459 		err(1, "socketpair");
460 
461 	switch (fork()) {
462 	case -1:
463 		err(1, "fork");
464 	case 0:
465 		/* child */
466 		setproctitle("(%d) client", pid);
467 		close(net_fds[0]);
468 		close(fs_fds[0]);
469 		imsg_init(&network_ibuf, net_fds[1]);
470 		exit(client_main(&network_ibuf));
471 	default:
472 		close(net_fds[1]);
473 		imsg_init(&network_ibuf, net_fds[0]);
474 		netibuf = &network_ibuf;
475 	}
476 
477 	setproctitle("(%d) ui", pid);
478 
479 	telescope_ohash_init(&certs, 5, offsetof(struct tofu_entry, domain));
480 	load_certs(&certs);
481 
482 	TAILQ_INIT(&tabshead);
483 
484 	event_init();
485 
486 	event_set(&netev, netibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, netibuf);
487 	event_add(&netev, NULL);
488 
489 	event_set(&fsev, fsibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, fsibuf);
490 	event_add(&fsev, NULL);
491 
492 	if (ui_init(argc, argv)) {
493 		sandbox_ui_process();
494 		event_dispatch();
495 		ui_end();
496 	}
497 
498 	imsg_compose(netibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
499 	imsg_flush(netibuf);
500 
501 	imsg_compose(fsibuf, IMSG_QUIT, 0, 0, -1, NULL, 0);
502 	imsg_flush(fsibuf);
503 
504 	return 0;
505 }