about summary refs log tree commit diff
path: root/bounce.c
blob: 9854145f3c2bdd136774fc8a7140f7cfc4312576 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * Additional permission under GNU GPL version 3 section 7:
 *
 * If you modify this Program, or any covered work, by linking or
 * combining it with OpenSSL (or a modified version of that library),
 * containing parts covered by the terms of the OpenSSL License and the
 * original SSLeay license, the licensors of this Program grant you
 * additional permission to convey the resulting work. Corresponding
 * Source for a non-source form of such a combination shall include the
 * source code for the parts of OpenSSL used as well as that of the
 * covered work.
 */

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <poll.h>
#include <pwd.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sysexits.h>
#include <time.h>
#include <tls.h>
#include <unistd.h>

#ifdef __FreeBSD__
#include <sys/capsicum.h>
#endif

// For getentropy(2):
#ifdef __APPLE__
#include <sys/random.h>
#endif

#ifndef SIGINFO
#define SIGINFO SIGUSR2
#endif

#include "bounce.h"

bool verbose;

static volatile sig_atomic_t signals[NSIG];
static void signalHandler(int signal) {
	signals[signal] = 1;
}
static void justExit(int signal) {
	exit(128 + signal);
}

static struct {
	struct pollfd *fds;
	struct Client **clients;
	size_t cap, len;
} event;

static void eventAdd(int fd, struct Client *client) {
	if (event.len == event.cap) {
		event.cap = (event.cap ? event.cap * 2 : 8);
		event.fds = realloc(event.fds, sizeof(*event.fds) * event.cap);
		if (!event.fds) err(EX_OSERR, "realloc");
		event.clients = realloc(
			event.clients, sizeof(*event.clients) * event.cap
		);
		if (!event.clients) err(EX_OSERR, "realloc");
	}
	event.fds[event.len] = (struct pollfd) { .fd = fd, .events = POLLIN };
	event.clients[event.len] = client;
	event.len++;
}

static void eventRemove(size_t i) {
	close(event.fds[i].fd);
	event.len--;
	event.fds[i] = event.fds[event.len];
	event.clients[i] = event.clients[event.len];
}

static FILE *saveFile;

static void saveSave(void) {
	int error = ringSave(saveFile);
	if (error) warn("fwrite");
	error = fclose(saveFile);
	if (error) warn("fclose");
}

static void saveLoad(const char *path) {
	umask(0066);
	saveFile = dataOpen(path, "a+");
	if (!saveFile) exit(EX_CANTCREAT);

	int error = flock(fileno(saveFile), LOCK_EX | LOCK_NB);
	if (error && errno != EWOULDBLOCK) err(EX_OSERR, "flock");
	if (error) errx(EX_CANTCREAT, "lock held by other process: %s", path);

	rewind(saveFile);
	ringLoad(saveFile);
	error = ftruncate(fileno(saveFile), 0);
	if (error) err(EX_IOERR, "ftruncate");

	atexit(saveSave);
}

#ifdef __FreeBSD__
static void capLimit(int fd, const cap_rights_t *rights) {
	int error = cap_rights_limit(fd, rights);
	if (error) err(EX_OSERR, "cap_rights_limit");
}
#endif

#ifdef __OpenBSD__
static void unveilParent(const char *path, const char *mode) {
	char buf[PATH_MAX];
	strlcpy(buf, path, sizeof(buf));
	char *base = strrchr(buf, '/');
	if (base) *base = '\0';
	int error = unveil((base ? buf : "."), mode);
	if (error && errno != ENOENT) err(EX_NOINPUT, "%s", path);
}

static void unveilTarget(const char *path, const char *mode) {
	char buf[PATH_MAX];
	strlcpy(buf, path, sizeof(buf));
	char *base = strrchr(buf, '/');
	base = (base ? base + 1 : buf);
	ssize_t len = readlink(path, base, sizeof(buf) - (base - buf) - 1);
	if (len < 0) return;
	base[len] = '\0';
	unveilParent(buf, mode);
}

static void unveilConfig(const char *path) {
	const char *dirs = NULL;
	for (const char *abs; NULL != (abs = configPath(&dirs, path));) {
		unveilParent(abs, "r");
		unveilTarget(abs, "r");
	}
}

static void unveilData(const char *path) {
	const char *dirs = NULL;
	for (const char *abs; NULL != (abs = dataPath(&dirs, path));) {
		int error = unveil(abs, "rwc");
		if (error && errno != ENOENT) err(EX_CANTCREAT, "%s", abs);
	}
}
#endif /* __OpenBSD__ */

static size_t parseSize(const char *str) {
	char *rest;
	size_t size = strtoull(str, &rest, 0);
	if (*rest) errx(EX_USAGE, "invalid size: %s", str);
	return size;
}

static struct timeval parseInterval(const char *str) {
	char *rest;
	long ms = strtol(str, &rest, 0);
	if (*rest) errx(EX_USAGE, "invalid interval: %s", str);
	return (struct timeval) {
		.tv_sec = ms / 1000,
		.tv_usec = 1000 * (ms % 1000),
	};
}

static void hashPass(void);
static void genCert(const char *path, const char *ca);

int main(int argc, char *argv[]) {
	int error;

	size_t ringSize = 4096;
	const char *savePath = NULL;

	const char *bindHost = "localhost";
	const char *bindPort = "6697";
	char bindPath[PATH_MAX] = "";
	char certPath[PATH_MAX] = "";
	char privPath[PATH_MAX] = "";
	const char *caPath = NULL;
	const char *genPath = NULL;

	bool insecure = false;
	const char *clientCert = NULL;
	const char *clientPriv = NULL;
	const char *serverBindHost = NULL;

	const char *host = NULL;
	const char *port = "6697";
	char *pass = NULL;
	char *plain = NULL;
	enum Cap blindReq = 0;
	const char *nick = NULL;
	const char *user = NULL;
	const char *real = NULL;

	const char *join = NULL;
	const char *quit = "connection reset by purr";

	struct option options[] = {
		{ .val = '!', .name = "insecure", no_argument },
		{ .val = 'A', .name = "local-ca", required_argument },
		{ .val = 'C', .name = "local-cert", required_argument },
		{ .val = 'H', .name = "local-host", required_argument },
		{ .val = 'K', .name = "local-priv", required_argument },
		{ .val = 'L', .name = "palaver", no_argument },
		{ .val = 'N', .name = "no-names", no_argument },
		{ .val = 'P', .name = "local-port", required_argument },
		{ .val = 'Q', .name = "queue-interval", required_argument },
		{ .val = 'R', .name = "blind-req", required_argument },
		{ .val = 'S', .name = "bind", required_argument },
		{ .val = 'T', .name = "no-sts", no_argument },
		{ .val = 'U', .name = "local-path", required_argument },
		{ .val = 'W', .name = "local-pass", required_argument },
		{ .val = 'a', .name = "sasl-plain", required_argument },
		{ .val = 'c', .name = "client-cert", required_argument },
		{ .val = 'e', .name = "sasl-external", no_argument },
		{ .val = 'f', .name = "save", required_argument },
		{ .val = 'g', .name = "generate", required_argument },
		{ .val = 'h', .name = "host", required_argument },
		{ .val = 'j', .name = "join", required_argument },
		{ .val = 'k', .name = "client-priv", required_argument },
		{ .val = 'n', .name = "nick", required_argument },
		{ .val = 'p', .name = "port", required_argument },
		{ .val = 'q', .name = "quit", required_argument },
		{ .val = 'r', .name = "real", required_argument },
		{ .val = 's', .name = "size", required_argument },
		{ .val = 'u', .name = "user", required_argument },
		{ .val = 'v', .name = "verbose", no_argument },
		{ .val = 'w', .name = "pass", required_argument },
		{ .val = 'x', .name = "hash", no_argument },
		{ .val = 'y', .name = "away", required_argument },
		{0},
	};
	char opts[2 * ARRAY_LEN(options)];
	for (size_t i = 0, j = 0; i < ARRAY_LEN(options); ++i) {
		opts[j++] = options[i].val;
		if (options[i].has_arg) opts[j++] = ':';
	}

	for (int opt; 0 < (opt = getopt_config(argc, argv, opts, options, NULL));) {
		switch (opt) {
			break; case '!': insecure = true;
			break; case 'A': caPath = optarg; clientCaps |= CapSASL;
			break; case 'C': snprintf(certPath, sizeof(certPath), "%s", optarg);
			break; case 'H': bindHost = optarg;
			break; case 'K': snprintf(privPath, sizeof(privPath), "%s", optarg);
			break; case 'N': stateNoNames = true;
			break; case 'L': clientCaps |= CapPalaverApp;
			break; case 'P': bindPort = optarg;
			break; case 'Q': serverQueueInterval = parseInterval(optarg);
			break; case 'R': blindReq |= capParse(optarg, NULL);
			break; case 'S': serverBindHost = optarg;
			break; case 'T': clientCaps &= ~CapSTS;
			break; case 'U': snprintf(bindPath, sizeof(bindPath), "%s", optarg);
			break; case 'W': clientPass = optarg;
			break; case 'a': blindReq |= CapSASL; plain = optarg;
			break; case 'c': clientCert = optarg;
			break; case 'e': blindReq |= CapSASL;
			break; case 'f': savePath = optarg;
			break; case 'g': genPath = optarg;
			break; case 'h': host = optarg;
			break; case 'j': join = optarg;
			break; case 'k': clientPriv = optarg;
			break; case 'n': nick = optarg;
			break; case 'p': port = optarg;
			break; case 'q': quit = optarg;
			break; case 'r': real = optarg;
			break; case 's': ringSize = parseSize(optarg);
			break; case 'u': user = optarg;
			break; case 'v': verbose = true;
			break; case 'w': pass = optarg;
			break; case 'x': hashPass(); return EX_OK;
			break; case 'y': clientAway = optarg;
			break; default:  return EX_USAGE;
		}
	}
	if (blindReq & CapUnsupported) errx(EX_CONFIG, "unsupported capability");
	if (genPath) genCert(genPath, caPath);

	if (bindPath[0]) {
		struct stat st;
		int error = stat(bindPath, &st);
		if (error && errno != ENOENT) err(EX_CANTCREAT, "%s", bindPath);
		if (S_ISDIR(st.st_mode)) {
			size_t len = strlen(bindPath);
			snprintf(&bindPath[len], sizeof(bindPath) - len, "/%s", bindHost);
		}
	}
	if (!certPath[0]) {
		snprintf(
			certPath, sizeof(certPath), CERTBOT_PATH "/live/%s/fullchain.pem",
			bindHost
		);
	}
	if (!privPath[0]) {
		snprintf(
			privPath, sizeof(privPath), CERTBOT_PATH "/live/%s/privkey.pem",
			bindHost
		);
	}

	if (!host) errx(EX_USAGE, "host required");
	if (!nick) {
		nick = getenv("USER");
		if (!nick) errx(EX_CONFIG, "USER unset");
	}
	if (!user) user = nick;
	if (!real) real = nick;
	if (!clientAway) clientAway = "pounced :3";
	if (clientPass && clientPass[0] != '$') {
		errx(EX_CONFIG, "password must be hashed with -x");
	}

#ifdef __OpenBSD__
	unveilConfig(certPath);
	unveilConfig(privPath);
	if (caPath) unveilConfig(caPath);
	if (clientCert) unveilConfig(clientCert);
	if (clientPriv) unveilConfig(clientPriv);
	if (savePath) unveilData(savePath);
	if (bindPath[0]) unveilParent(bindPath, "rwc");

	error = unveil(tls_default_ca_cert_file(), "r");
	if (error) err(EX_OSFILE, "%s", tls_default_ca_cert_file());

	error = pledge("stdio rpath wpath cpath inet flock unix dns recvfd", NULL);
	if (error) err(EX_OSERR, "pledge");
#endif

	// Either exit with cleanup or ignore signals until entering the main loop.
	signal(SIGINT, justExit);
	signal(SIGTERM, justExit);
	signal(SIGINFO, SIG_IGN);
	signal(SIGUSR1, SIG_IGN);

	ringAlloc(ringSize);
	if (savePath) saveLoad(savePath);

	struct Cert localCA = { -1, -1, "" };
	if (caPath) {
		error = 0;
		const char *dirs = NULL;
		for (const char *path; NULL != (path = configPath(&dirs, caPath));) {
			error = certOpen(&localCA, path);
			if (!error) break;
		}
		if (error) err(EX_NOINPUT, "%s", caPath);
	}

	const char *dirs;
	struct Cert cert;
	struct Cert priv;
	dirs = NULL;
	for (const char *path; NULL != (path = configPath(&dirs, certPath));) {
		error = certOpen(&cert, path);
		if (!error) break;
	}
	if (error) err(EX_NOINPUT, "%s", certPath);
	dirs = NULL;
	for (const char *path; NULL != (path = configPath(&dirs, privPath));) {
		error = certOpen(&priv, path);
		if (!error) break;
	}
	if (error) err(EX_NOINPUT, "%s", privPath);

	FILE *certRead = certFile(&cert);
	if (!certRead) err(EX_NOINPUT, "%s", certPath);
	FILE *privRead = certFile(&priv);
	if (!privRead) err(EX_NOINPUT, "%s", privPath);
	FILE *caRead = (caPath ? certFile(&localCA) : NULL);
	if (caPath && !caRead) err(EX_NOINPUT, "%s", caPath);

	localConfig(certRead, privRead, caRead, !clientPass);
	fclose(certRead);
	fclose(privRead);
	if (caPath) fclose(caRead);

	int bind[8];
	size_t binds = bindPath[0]
		? localUnix(bind, ARRAY_LEN(bind), bindPath)
		: localBind(bind, ARRAY_LEN(bind), bindHost, bindPort);

	serverConfig(insecure, clientCert, clientPriv);
	int server = serverConnect(serverBindHost, host, port);

#ifdef __FreeBSD__
	error = cap_enter();
	if (error) err(EX_OSERR, "cap_enter");

	cap_rights_t saveRights, fileRights, sockRights, bindRights;
	cap_rights_init(&saveRights, CAP_WRITE);
	cap_rights_init(&fileRights, CAP_FCNTL, CAP_FSTAT, CAP_LOOKUP, CAP_PREAD);
	cap_rights_init(&sockRights, CAP_EVENT, CAP_RECV, CAP_SEND, CAP_SETSOCKOPT);
	cap_rights_init(&bindRights, CAP_LISTEN, CAP_ACCEPT);
	cap_rights_merge(&bindRights, &sockRights);

	if (saveFile) capLimit(fileno(saveFile), &saveRights);
	capLimit(cert.parent, &fileRights);
	capLimit(cert.target, &fileRights);
	capLimit(priv.parent, &fileRights);
	capLimit(priv.target, &fileRights);
	if (caPath) {
		capLimit(localCA.parent, &fileRights);
		capLimit(localCA.target, &fileRights);
	}
	for (size_t i = 0; i < binds; ++i) {
		capLimit(bind[i], &bindRights);
	}
	capLimit(server, &sockRights);
#endif

	stateLogin(pass, blindReq, plain, nick, user, real);
	if (pass) explicit_bzero(pass, strlen(pass));
	if (plain) explicit_bzero(plain, strlen(plain));

	while (!stateReady()) serverRecv();
	serverFormat("AWAY :%s\r\n", clientAway);
	if (join) serverFormat("JOIN :%s\r\n", join);

	signal(SIGINT, signalHandler);
	signal(SIGTERM, signalHandler);
	signal(SIGPIPE, SIG_IGN);
	signal(SIGALRM, signalHandler);
	signal(SIGINFO, signalHandler);
	signal(SIGUSR1, signalHandler);

	for (size_t i = 0; i < binds; ++i) {
		error = listen(bind[i], -1);
		if (error) err(EX_IOERR, "listen");
		eventAdd(bind[i], NULL);
	}
	eventAdd(server, NULL);
	size_t clientIndex = event.len;

	for (;;) {
		enum Need needs = 0;
		for (size_t i = clientIndex; i < event.len; ++i) {
			event.fds[i].events = POLLIN;
			if (clientDiff(event.clients[i])) {
				event.fds[i].events |= POLLOUT;
			}
			needs |= event.clients[i]->need;
		}

		int timeout = 10000;
		int ready = poll(event.fds, event.len, (needs ? timeout : -1));
		if (ready < 0 && errno != EINTR) err(EX_IOERR, "poll");

		if (needs) {
			time_t now = time(NULL);
			for (size_t i = event.len - 1; i >= clientIndex; --i) {
				struct Client *client = event.clients[i];
				if (!client->need) continue;
				if (now - client->time < timeout / 1000) continue;
				clientFree(client);
				eventRemove(i);
			}
		}

		for (size_t i = event.len - 1; ready > 0 && i < event.len; --i) {
			short revents = event.fds[i].revents;
			if (!revents) continue;

			struct Client *client = event.clients[i];
			if (client) {
				if (revents & POLLOUT) clientConsume(client);
				if (revents & POLLIN) clientRecv(client);
				if (client->error || revents & (POLLHUP | POLLERR)) {
					clientFree(client);
					eventRemove(i);
				}
			} else if (event.fds[i].fd == server) {
				serverRecv();
			} else {
				struct tls *tls = NULL;
				int sock = localAccept(&tls, event.fds[i].fd);
				if (sock < 0) {
					warn("accept");
					continue;
				}
				eventAdd(sock, clientAlloc(sock, tls));
			}
		}

		if (signals[SIGINT] || signals[SIGTERM]) {
			break;
		}
		if (signals[SIGALRM]) {
			signals[SIGALRM] = 0;
			serverDequeue();
		}
		if (signals[SIGINFO]) {
			signals[SIGINFO] = 0;
			ringInfo();
		}
		if (signals[SIGUSR1]) {
			signals[SIGUSR1] = 0;
			certRead = certFile(&cert);
			privRead = certFile(&priv);
			if (caPath) caRead = certFile(&localCA);
			if (!certRead) warn("%s", certPath);
			if (!privRead) warn("%s", privPath);
			if (!caRead && caPath) warn("%s", caPath);
			if (!certRead || !privRead || (!caRead && caPath)) continue;
			localConfig(certRead, privRead, caRead, !clientPass);
			fclose(certRead);
			fclose(privRead);
			if (caPath) fclose(caRead);
		}
	}

	serverFormat("QUIT :%s\r\n", quit);
	for (size_t i = clientIndex; i < event.len; ++i) {
		struct Client *client = event.clients[i];
		if (!client->need) {
			clientFormat(
				client, ":%s QUIT :%s\r\nERROR :Disconnecting\r\n",
				stateEcho(), quit
			);
		}
		clientFree(client);
	}
}

#ifdef __OpenBSD__
static void hashPass(void) {
	char hash[_PASSWORD_LEN];
	char *pass = getpass("Password: ");
	int error = crypt_newhash(pass, "bcrypt,a", hash, sizeof(hash));
	if (error) err(EX_OSERR, "crypt_newhash");
	printf("%s\n", hash);
}
#else
static void hashPass(void) {
	byte rand[12];
	int error = getentropy(rand, sizeof(rand));
	if (error) err(EX_OSERR, "getentropy");

	char salt[3 + BASE64_SIZE(sizeof(rand))] = "$6$";
	base64(&salt[3], rand, sizeof(rand));

	char *pass = getpass("Password: ");
	printf("%s\n", crypt(pass, salt));
}
#endif

static void genReq(const char *path) {
	const char *name = strrchr(path, '/');
	name = (name ? &name[1] : path);
	char subj[256];
	snprintf(subj, sizeof(subj), "/CN=%.*s", (int)strcspn(name, "."), name);
	execlp(
		OPENSSL_BIN, "openssl", "req",
		"-new", "-newkey", "rsa:4096", "-sha256", "-nodes",
		"-subj", subj, "-keyout", path,
		NULL
	);
	err(EX_UNAVAILABLE, "openssl");
}

static void redir(int dst, int src) {
	int fd = dup2(src, dst);
	if (fd < 0) err(EX_OSERR, "dup2");
	close(src);
}

static void genCert(const char *path, const char *ca) {
	int out = open(path, O_WRONLY | O_APPEND | O_CREAT, 0600);
	if (out < 0) err(EX_CANTCREAT, "%s", path);

	int rw[2];
	int error = pipe(rw);
	if (error) err(EX_OSERR, "pipe");

	pid_t pid = fork();
	if (pid < 0) err(EX_OSERR, "fork");
	if (!pid) {
		close(rw[0]);
		redir(STDOUT_FILENO, rw[1]);
		genReq(path);
	}

	close(rw[1]);
	redir(STDIN_FILENO, rw[0]);
	redir(STDOUT_FILENO, out);
	execlp(
		OPENSSL_BIN, "openssl", "x509",
		"-req", "-days", "3650", "-CAcreateserial",
		(ca ? "-CA" : "-signkey"), (ca ? ca : path),
		NULL
	);
	err(EX_UNAVAILABLE, "openssl");
}