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Date:: Mon Jul 26 20:23:53 2021 UTC
Message:: improve logging if getpwnam fails it doesn't set errno when fails to find a user (which is correct, since a missing user is not *technically* an error, but still...)
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1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
4  * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
5  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
6  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
7  *
8  * Permission to use, copy, modify, and distribute this software for any
9  * purpose with or without fee is hereby granted, provided that the above
10  * copyright notice and this permission notice appear in all copies.
11  *
12  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
15  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
18  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19  */
20 
21 #include <sys/socket.h>
22 #include <sys/wait.h>
23 
24 #include <arpa/inet.h>
25 #include <netinet/in.h>
26 
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <pwd.h>
30 #include <signal.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <syslog.h>
35 #include <unistd.h>
36 
37 #include "client.h"
38 #include "control.h"
39 #include "kamid.h"
40 #include "listener.h"
41 #include "log.h"
42 #include "sandbox.h"
43 #include "table.h"
44 #include "utils.h"
45 
46 enum kd_process {
47 	PROC_MAIN,
48 	PROC_LISTENER,
49 	PROC_CLIENTCONN,
50 };
51 
52 const char	*saved_argv0;
53 static int	 debug, nflag;
54 int		 verbose;
55 
56 ATTR_DEAD void	usage(void);
57 
58 void		main_sig_handler(int, short, void *);
59 void		main_dispatch_listener(int, short, void *);
60 int		main_reload(void);
61 int		main_imsg_send_config(struct kd_conf *);
62 void		main_dispatch_listener(int, short, void *);
63 ATTR_DEAD void	main_shutdown(void);
64 
65 static pid_t	start_child(enum kd_process, int, int, int);
66 
67 struct kd_conf		*main_conf;
68 static struct imsgev	*iev_listener;
69 const char		*conffile;
70 pid_t			 listener_pid;
71 uint32_t		 cmd_opts;
72 
73 ATTR_DEAD void
74 usage(void)
75 {
76 	fprintf(stderr, "usage: %s [-dnv] [-f file] [-s socket]\n",
77 	    getprogname());
78 	exit(1);
79 }
80 
81 int
82 main(int argc, char **argv)
83 {
84         struct event	 ev_sigint, ev_sigterm, ev_sighup;
85 	int		 ch;
86 	int		 listener_flag = 0, client_flag = 0;
87 	int		 pipe_main2listener[2];
88 	int		 control_fd;
89 	const char	*csock;
90 
91 	conffile = KD_CONF_FILE;
92 	csock = KD_SOCKET;
93 
94 	log_init(1, LOG_DAEMON);	/* Log to stderr until deamonized. */
95 	log_setverbose(1);
96 
97 	saved_argv0 = argv[0];
98 	if (saved_argv0 == NULL)
99 		saved_argv0 = "kamid";
100 
101 	while ((ch = getopt(argc, argv, "D:df:nsT:v")) != -1) {
102 		switch (ch) {
103 		case 'D':
104 			if (cmdline_symset(optarg) == -1)
105                                 log_warnx("could not parse macro definition %s",
106 					optarg);
107 			break;
108 		case 'd':
109 			debug = 1;
110 			break;
111 		case 'f':
112 			conffile = optarg;
113 			break;
114 		case 'n':
115 			nflag = 1;
116 			break;
117 		case 's':
118 			csock = optarg;
119 			break;
120 		case 'T':
121 			switch (*optarg) {
122 			case 'c':
123 				client_flag = 1;
124 				break;
125 			case 'l':
126 				listener_flag = 1;
127 				break;
128 			default:
129 				fatalx("invalid process spec %c", *optarg);
130 			}
131 			break;
132 		case 'v':
133 			verbose = 1;
134 			break;
135 		default:
136 			usage();
137 		}
138 	}
139 
140 	argc -= optind;
141 	argv += optind;
142 	if (argc > 0 || (listener_flag && client_flag))
143 		usage();
144 
145 	if (client_flag)
146 		client(debug, verbose);
147 	else if (listener_flag)
148 		listener(debug, verbose);
149 
150 	if ((main_conf = parse_config(conffile)) == NULL)
151 		exit(1);
152 
153 	if (nflag) {
154 		fprintf(stderr, "configuration OK\n");
155 		exit(0);
156 	}
157 
158 	/* Check for root privileges. */
159         if (geteuid())
160                 fatalx("need root privileges");
161 
162 	/* Check for assigned daemon user. */
163 	if (getpwnam(KD_USER) == NULL)
164 		fatalx("unknown user %s", KD_USER);
165 
166 	log_init(debug, LOG_DAEMON);
167 	log_setverbose(verbose);
168 
169 	if (!debug)
170 		daemon(1, 0);
171 
172 	log_info("startup");
173 
174 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
175 	    PF_UNSPEC, pipe_main2listener) == -1)
176 		fatal("main2listener socketpair");
177 
178 	/* Start children. */
179 	listener_pid = start_child(PROC_LISTENER, pipe_main2listener[1],
180 	    debug, verbose);
181 
182 	log_procinit("main");
183 
184 	event_init();
185 
186 	/* Setup signal handler */
187 	signal_set(&ev_sigint, SIGINT, main_sig_handler, NULL);
188 	signal_set(&ev_sigterm, SIGTERM, main_sig_handler, NULL);
189 	signal_set(&ev_sighup, SIGHUP, main_sig_handler, NULL);
190 
191 	signal_add(&ev_sigint, NULL);
192 	signal_add(&ev_sigterm, NULL);
193 	signal_add(&ev_sighup, NULL);
194 
195 	signal(SIGCHLD, SIG_IGN);
196 	signal(SIGPIPE, SIG_IGN);
197 
198 	if ((iev_listener = malloc(sizeof(*iev_listener))) == NULL)
199 		fatal(NULL);
200 	imsg_init(&iev_listener->ibuf, pipe_main2listener[0]);
201 	iev_listener->handler = main_dispatch_listener;
202 
203 	/* Setup event handlers for pipes to listener. */
204 	iev_listener->events = EV_READ;
205 	event_set(&iev_listener->ev, iev_listener->ibuf.fd,
206 	    iev_listener->events, iev_listener->handler, iev_listener);
207 	event_add(&iev_listener->ev, NULL);
208 
209 	if ((control_fd = control_init(csock)) == -1)
210 		fatalx("control socket setup failed");
211 
212 	main_imsg_compose_listener(IMSG_CONTROLFD, control_fd, 0,
213 	    NULL, 0);
214 	main_imsg_send_config(main_conf);
215 
216 	sandbox_main();
217 
218 	event_dispatch();
219 
220 	main_shutdown();
221 	return 0;
222 }
223 
224 void
225 main_sig_handler(int sig, short event, void *arg)
226 {
227 	/*
228 	 * Normal signal handler rules don't apply because libevent
229 	 * decouples for us.
230 	 */
231 
232 	switch (sig) {
233 	case SIGTERM:
234 	case SIGINT:
235 		main_shutdown();
236 		break;
237 	case SIGHUP:
238 		if (main_reload() == -1)
239 			log_warnx("configuration reload failed");
240 		else
241 			log_debug("configuration reloaded");
242 		break;
243 	default:
244 		fatalx("unexpected signal %d", sig);
245 	}
246 }
247 
248 static inline struct table *
249 auth_table_by_id(uint32_t id)
250 {
251 	struct kd_listen_conf *listen;
252 
253 	STAILQ_FOREACH(listen, &main_conf->listen_head, entry) {
254 		if (listen->id == id)
255 			return listen->auth_table;
256 	}
257 
258 	return NULL;
259 }
260 
261 static inline void
262 do_auth_tls(struct imsg *imsg)
263 {
264 	char *username = NULL;
265 	struct passwd *pw;
266 	struct table *t;
267 	struct kd_auth_req auth;
268 	int p[2];
269 
270 	if (sizeof(auth) != IMSG_DATA_SIZE(*imsg))
271 		fatal("wrong size for IMSG_AUTH_TLS: "
272 		    "got %lu; want %lu", IMSG_DATA_SIZE(*imsg),
273 		    sizeof(auth));
274 	memcpy(&auth, imsg->data, sizeof(auth));
275 
276 	if (memmem(auth.hash, sizeof(auth.hash), "", 1) == NULL)
277                 fatal("non NUL-terminated hash received");
278 
279 	log_debug("tls id=%u hash=%s", auth.listen_id, auth.hash);
280 
281 	if ((t = auth_table_by_id(auth.listen_id)) == NULL)
282 		fatal("request for invalid listener id %d", imsg->hdr.pid);
283 
284 	log_debug("before table_lookup");
285 	if (table_lookup(t, auth.hash, &username) == -1) {
286 		log_warnx("login failed for hash %s", auth.hash);
287 		goto err;
288 	}
289 
290 	log_debug("matched local user %s", username);
291 
292 	if ((pw = getpwnam(username)) == NULL) {
293 		log_warnx("getpwnam(%s) failed", username);
294 		goto err;
295 	}
296 
297 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
298 	    PF_UNSPEC, p) == -1)
299 		fatal("socketpair");
300 
301 	start_child(PROC_CLIENTCONN, p[1], debug, verbose);
302 
303 	main_imsg_compose_listener(IMSG_AUTH, p[0], imsg->hdr.peerid,
304 	    username, strlen(username)+1);
305 	main_imsg_compose_listener(IMSG_AUTH_DIR, -1, imsg->hdr.peerid,
306 	    pw->pw_dir, strlen(pw->pw_dir)+1);
307 
308 	free(username);
309 	return;
310 
311 err:
312 	free(username);
313 	main_imsg_compose_listener(IMSG_AUTH, -1, imsg->hdr.peerid,
314 	    NULL, 0);
315 }
316 
317 void
318 main_dispatch_listener(int fd, short event, void *d)
319 {
320 	struct imsgev	*iev = d;
321 	struct imsgbuf	*ibuf;
322 	struct imsg	 imsg;
323 	ssize_t		 n;
324 	int		 shut = 0;
325 
326 	ibuf = &iev->ibuf;
327 
328 	if (event & EV_READ) {
329 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
330 			fatal("imsg_read error");
331 		if (n == 0)	/* Connection closed. */
332 			shut = 1;
333 	}
334 	if (event & EV_WRITE) {
335 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
336 			fatal("msgbuf_write");
337 		if (n == 0)	/* Connection closed. */
338 			shut = 1;
339 	}
340 
341 	for (;;) {
342 		if ((n = imsg_get(ibuf, &imsg)) == -1)
343 			fatal("imsg_get");
344 		if (n == 0)	/* No more messages. */
345 			break;
346 
347 		switch (imsg.hdr.type) {
348 		case IMSG_AUTH_TLS:
349 			do_auth_tls(&imsg);
350 			break;
351 		default:
352 			log_debug("%s: error handling imsg %d", __func__,
353 				imsg.hdr.type);
354 			break;
355 		}
356 		imsg_free(&imsg);
357 	}
358 	if (!shut)
359 		imsg_event_add(iev);
360 	else {
361 		/* This pipe is dead.  Remove its event handler. */
362 		event_del(&iev->ev);
363 		event_loopexit(NULL);
364 	}
365 }
366 
367 int
368 main_reload(void)
369 {
370 	struct kd_conf *xconf;
371 
372 	if ((xconf = parse_config(conffile)) == NULL)
373 		return -1;
374 
375 	if (main_imsg_send_config(xconf) == -1)
376 		return -1;
377 
378 	merge_config(main_conf, xconf);
379 
380 	return 0;
381 }
382 
383 static inline int
384 make_socket_for(struct kd_listen_conf *l)
385 {
386 	struct sockaddr_in	addr4;
387 	size_t			len;
388 	int			fd, v;
389 
390 	memset(&addr4, 0, sizeof(addr4));
391 	addr4.sin_family = AF_INET;
392 	addr4.sin_port = htons(l->port);
393 	addr4.sin_addr.s_addr = INADDR_ANY;
394 
395 	if ((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
396 		fatal("socket");
397 
398 	v = 1;
399 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
400 		fatal("setsockopt(SO_REUSEADDR)");
401 
402 	v = 1;
403 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
404 		fatal("setsockopt(SO_REUSEPORT)");
405 
406 	len = sizeof(addr4);
407 	if (bind(fd, (struct sockaddr *)&addr4, len) == -1)
408 		fatal("bind(%s, %d)", l->iface, l->port);
409 
410 	if (listen(fd, 16) == -1)
411 		fatal("l(%s, %d)", l->iface, l->port);
412 
413 	return fd;
414 }
415 
416 int
417 main_imsg_send_config(struct kd_conf *xconf)
418 {
419 	struct kd_pki_conf *pki;
420 	struct kd_listen_conf *listen;
421 
422 #define SEND(type, fd, data, len) do {					\
423 		if (main_imsg_compose_listener(type, fd, 0, data, len)	\
424 		    == -1)						\
425 			return -1;					\
426 	} while (0)
427 
428 	/* Send fixed part of config to children. */
429 	SEND(IMSG_RECONF_CONF, -1, xconf, sizeof(*xconf));
430 
431 	STAILQ_FOREACH(pki, &xconf->pki_head, entry) {
432 		log_debug("sending pki %s", pki->name);
433 		SEND(IMSG_RECONF_PKI, -1, pki->name, sizeof(pki->name));
434 		SEND(IMSG_RECONF_PKI_CERT, -1, pki->cert, pki->certlen);
435 		SEND(IMSG_RECONF_PKI_KEY, -1, pki->key, pki->keylen);
436 	}
437 
438 	STAILQ_FOREACH(listen, &xconf->listen_head, entry) {
439 		log_debug("sending listen on port %d", listen->port);
440 		SEND(IMSG_RECONF_LISTEN, make_socket_for(listen), listen,
441 		    sizeof(*listen));
442 	}
443 
444 	SEND(IMSG_RECONF_END, -1, NULL, 0);
445 	return 0;
446 
447 #undef SEND
448 }
449 
450 void
451 merge_config(struct kd_conf *conf, struct kd_conf *xconf)
452 {
453 	/* do stuff... */
454 
455 	free(xconf);
456 }
457 
458 struct kd_conf *
459 config_new_empty(void)
460 {
461 	struct kd_conf *xconf;
462 
463 	if ((xconf = calloc(1, sizeof(*xconf))) == NULL)
464 		fatal(NULL);
465 
466 	/* set default values */
467 
468 	return xconf;
469 }
470 
471 void
472 config_clear(struct kd_conf *conf)
473 {
474 	struct kd_conf *xconf;
475 
476 	/* Merge current config with an empty one. */
477 	xconf = config_new_empty();
478 	merge_config(conf, xconf);
479 
480 	free(conf);
481 }
482 
483 ATTR_DEAD void
484 main_shutdown(void)
485 {
486 	pid_t	pid;
487 	int	status;
488 
489 	/* close pipes. */
490         config_clear(main_conf);
491 
492 	log_debug("waiting for children to terminate");
493 	do {
494 		pid = wait(&status);
495 		if (pid == -1) {
496 			if (errno != EINTR && errno != ECHILD)
497 				fatal("wait");
498 		} else if (WIFSIGNALED(status))
499 			log_warnx("%s terminated; signal %d",
500 			    (pid == listener_pid) ? "logger" : "clientconn",
501 			    WTERMSIG(status));
502 	} while (pid != -1 || (pid == -1 && errno == EINTR));
503 
504 	free(iev_listener);
505 
506 	log_info("terminating");
507 	exit(0);
508 }
509 
510 static pid_t
511 start_child(enum kd_process p, int fd, int debug, int verbose)
512 {
513 	const char	*argv[5];
514 	int		 argc = 0;
515 	pid_t		 pid;
516 
517 	switch (pid = fork()) {
518 	case -1:
519 		fatal("cannot fork");
520 	case 0:
521 		break;
522 	default:
523 		close(fd);
524 		return pid;
525 	}
526 
527 	if (fd != 3) {
528 		if (dup2(fd, 3) == -1)
529 			fatal("cannot setup imsg fd");
530 	} else if (fcntl(F_SETFD, 0) == -1)
531 		fatal("cannot setup imsg fd");
532 
533 	argv[argc++] = saved_argv0;
534 	switch (p) {
535 	case PROC_MAIN:
536 		fatalx("Can not start main process");
537 	case PROC_LISTENER:
538 		argv[argc++] = "-Tl";
539 		break;
540 	case PROC_CLIENTCONN:
541 		argv[argc++] = "-Tc";
542 		break;
543 	}
544 	if (debug)
545 		argv[argc++] = "-d";
546 	if (verbose)
547 		argv[argc++] = "-v";
548 	argv[argc++] = NULL;
549 
550 	/* really? */
551 	execvp(saved_argv0, (char *const *)argv);
552 	fatal("execvp");
553 }
554 
555 void
556 imsg_event_add(struct imsgev *iev)
557 {
558 	iev->events = EV_READ;
559 	if (iev->ibuf.w.queued)
560 		iev->events |= EV_WRITE;
561 
562 	event_del(&iev->ev);
563 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
564 	event_add(&iev->ev, NULL);
565 }
566 
567 int
568 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
569     pid_t pid, int fd, const void *data, uint16_t datalen)
570 {
571 	int	ret;
572 
573 	if ((ret = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data,
574 	    datalen) != -1))
575 		imsg_event_add(iev);
576 
577 	return ret;
578 }
579 
580 int
581 main_imsg_compose_listener(int type, int fd, uint32_t peerid,
582     const void *data, uint16_t datalen)
583 {
584 	if (iev_listener)
585 		return imsg_compose_event(iev_listener, type, peerid, 0,
586 		    fd, data, datalen);
587 	else
588 		return -1;
589 }