1 /* $OpenBSD: ssh-agent.c,v 1.231 2018/05/11 03:38:51 djm Exp $ */
2 /*
3 * Author: Tatu Ylonen <[email protected]>
4 * Copyright (c) 1995 Tatu Ylonen <[email protected]>, Espoo, Finland
5 * All rights reserved
6 * The authentication agent program.
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 *
14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 */
36
37 #include "includes.h"
38 __RCSID("$FreeBSD$");
39
40 #include <sys/types.h>
41 #include <sys/param.h>
42 #include <sys/resource.h>
43 #include <sys/stat.h>
44 #include <sys/socket.h>
45 #ifdef HAVE_SYS_TIME_H
46 # include <sys/time.h>
47 #endif
48 #ifdef HAVE_SYS_UN_H
49 # include <sys/un.h>
50 #endif
51 #include "openbsd-compat/sys-queue.h"
52
53 #ifdef WITH_OPENSSL
54 #include <openssl/evp.h>
55 #include "openbsd-compat/openssl-compat.h"
56 #endif
57
58 #include <errno.h>
59 #include <fcntl.h>
60 #include <limits.h>
61 #ifdef HAVE_PATHS_H
62 # include <paths.h>
63 #endif
64 #ifdef HAVE_POLL_H
65 # include <poll.h>
66 #endif
67 #include <signal.h>
68 #include <stdarg.h>
69 #include <stdio.h>
70 #include <stdlib.h>
71 #include <time.h>
72 #include <string.h>
73 #include <unistd.h>
74 #ifdef HAVE_UTIL_H
75 # include <util.h>
76 #endif
77
78 #include "xmalloc.h"
79 #include "ssh.h"
80 #include "sshbuf.h"
81 #include "sshkey.h"
82 #include "authfd.h"
83 #include "compat.h"
84 #include "log.h"
85 #include "misc.h"
86 #include "digest.h"
87 #include "ssherr.h"
88 #include "match.h"
89
90 #ifdef ENABLE_PKCS11
91 #include "ssh-pkcs11.h"
92 #endif
93
94 #ifndef DEFAULT_PKCS11_WHITELIST
95 # define DEFAULT_PKCS11_WHITELIST "/usr/lib*/*,/usr/local/lib*/*"
96 #endif
97
98 /* Maximum accepted message length */
99 #define AGENT_MAX_LEN (256*1024)
100
101 typedef enum {
102 AUTH_UNUSED,
103 AUTH_SOCKET,
104 AUTH_CONNECTION
105 } sock_type;
106
107 typedef struct {
108 int fd;
109 sock_type type;
110 struct sshbuf *input;
111 struct sshbuf *output;
112 struct sshbuf *request;
113 } SocketEntry;
114
115 u_int sockets_alloc = 0;
116 SocketEntry *sockets = NULL;
117
118 typedef struct identity {
119 TAILQ_ENTRY(identity) next;
120 struct sshkey *key;
121 char *comment;
122 char *provider;
123 time_t death;
124 u_int confirm;
125 } Identity;
126
127 struct idtable {
128 int nentries;
129 TAILQ_HEAD(idqueue, identity) idlist;
130 };
131
132 /* private key table */
133 struct idtable *idtab;
134
135 int max_fd = 0;
136
137 /* pid of shell == parent of agent */
138 pid_t parent_pid = -1;
139 time_t parent_alive_interval = 0;
140
141 /* pid of process for which cleanup_socket is applicable */
142 pid_t cleanup_pid = 0;
143
144 /* pathname and directory for AUTH_SOCKET */
145 char socket_name[PATH_MAX];
146 char socket_dir[PATH_MAX];
147
148 /* PKCS#11 path whitelist */
149 static char *pkcs11_whitelist;
150
151 /* locking */
152 #define LOCK_SIZE 32
153 #define LOCK_SALT_SIZE 16
154 #define LOCK_ROUNDS 1
155 int locked = 0;
156 u_char lock_pwhash[LOCK_SIZE];
157 u_char lock_salt[LOCK_SALT_SIZE];
158
159 extern char *__progname;
160
161 /* Default lifetime in seconds (0 == forever) */
162 static long lifetime = 0;
163
164 static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
165
166 /*
167 * Client connection count; incremented in new_socket() and decremented in
168 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is
169 * normally initialized to 1, it will never reach 0. However, if the -x
170 * option is specified, it is initialized to 0 in main(); in that case,
171 * ssh-agent will exit as soon as it has had at least one client but no
172 * longer has any.
173 */
174 static int xcount = 1;
175
176 static void
close_socket(SocketEntry * e)177 close_socket(SocketEntry *e)
178 {
179 int last = 0;
180
181 if (e->type == AUTH_CONNECTION) {
182 debug("xcount %d -> %d", xcount, xcount - 1);
183 if (--xcount == 0)
184 last = 1;
185 }
186 close(e->fd);
187 e->fd = -1;
188 e->type = AUTH_UNUSED;
189 sshbuf_free(e->input);
190 sshbuf_free(e->output);
191 sshbuf_free(e->request);
192 if (last)
193 cleanup_exit(0);
194 }
195
196 static void
idtab_init(void)197 idtab_init(void)
198 {
199 idtab = xcalloc(1, sizeof(*idtab));
200 TAILQ_INIT(&idtab->idlist);
201 idtab->nentries = 0;
202 }
203
204 static void
free_identity(Identity * id)205 free_identity(Identity *id)
206 {
207 sshkey_free(id->key);
208 free(id->provider);
209 free(id->comment);
210 free(id);
211 }
212
213 /* return matching private key for given public key */
214 static Identity *
lookup_identity(struct sshkey * key)215 lookup_identity(struct sshkey *key)
216 {
217 Identity *id;
218
219 TAILQ_FOREACH(id, &idtab->idlist, next) {
220 if (sshkey_equal(key, id->key))
221 return (id);
222 }
223 return (NULL);
224 }
225
226 /* Check confirmation of keysign request */
227 static int
confirm_key(Identity * id)228 confirm_key(Identity *id)
229 {
230 char *p;
231 int ret = -1;
232
233 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
234 if (p != NULL &&
235 ask_permission("Allow use of key %s?\nKey fingerprint %s.",
236 id->comment, p))
237 ret = 0;
238 free(p);
239
240 return (ret);
241 }
242
243 static void
send_status(SocketEntry * e,int success)244 send_status(SocketEntry *e, int success)
245 {
246 int r;
247
248 if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
249 (r = sshbuf_put_u8(e->output, success ?
250 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
251 fatal("%s: buffer error: %s", __func__, ssh_err(r));
252 }
253
254 /* send list of supported public keys to 'client' */
255 static void
process_request_identities(SocketEntry * e)256 process_request_identities(SocketEntry *e)
257 {
258 Identity *id;
259 struct sshbuf *msg;
260 int r;
261
262 if ((msg = sshbuf_new()) == NULL)
263 fatal("%s: sshbuf_new failed", __func__);
264 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
265 (r = sshbuf_put_u32(msg, idtab->nentries)) != 0)
266 fatal("%s: buffer error: %s", __func__, ssh_err(r));
267 TAILQ_FOREACH(id, &idtab->idlist, next) {
268 if ((r = sshkey_puts_opts(id->key, msg, SSHKEY_SERIALIZE_INFO))
269 != 0 ||
270 (r = sshbuf_put_cstring(msg, id->comment)) != 0) {
271 error("%s: put key/comment: %s", __func__,
272 ssh_err(r));
273 continue;
274 }
275 }
276 if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
277 fatal("%s: buffer error: %s", __func__, ssh_err(r));
278 sshbuf_free(msg);
279 }
280
281
282 static char *
agent_decode_alg(struct sshkey * key,u_int flags)283 agent_decode_alg(struct sshkey *key, u_int flags)
284 {
285 if (key->type == KEY_RSA) {
286 if (flags & SSH_AGENT_RSA_SHA2_256)
287 return "rsa-sha2-256";
288 else if (flags & SSH_AGENT_RSA_SHA2_512)
289 return "rsa-sha2-512";
290 }
291 return NULL;
292 }
293
294 /* ssh2 only */
295 static void
process_sign_request2(SocketEntry * e)296 process_sign_request2(SocketEntry *e)
297 {
298 const u_char *data;
299 u_char *signature = NULL;
300 size_t dlen, slen = 0;
301 u_int compat = 0, flags;
302 int r, ok = -1;
303 struct sshbuf *msg;
304 struct sshkey *key = NULL;
305 struct identity *id;
306
307 if ((msg = sshbuf_new()) == NULL)
308 fatal("%s: sshbuf_new failed", __func__);
309 if ((r = sshkey_froms(e->request, &key)) != 0 ||
310 (r = sshbuf_get_string_direct(e->request, &data, &dlen)) != 0 ||
311 (r = sshbuf_get_u32(e->request, &flags)) != 0) {
312 error("%s: couldn't parse request: %s", __func__, ssh_err(r));
313 goto send;
314 }
315
316 if ((id = lookup_identity(key)) == NULL) {
317 verbose("%s: %s key not found", __func__, sshkey_type(key));
318 goto send;
319 }
320 if (id->confirm && confirm_key(id) != 0) {
321 verbose("%s: user refused key", __func__);
322 goto send;
323 }
324 if ((r = sshkey_sign(id->key, &signature, &slen,
325 data, dlen, agent_decode_alg(key, flags), compat)) != 0) {
326 error("%s: sshkey_sign: %s", __func__, ssh_err(r));
327 goto send;
328 }
329 /* Success */
330 ok = 0;
331 send:
332 sshkey_free(key);
333 if (ok == 0) {
334 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
335 (r = sshbuf_put_string(msg, signature, slen)) != 0)
336 fatal("%s: buffer error: %s", __func__, ssh_err(r));
337 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
338 fatal("%s: buffer error: %s", __func__, ssh_err(r));
339
340 if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
341 fatal("%s: buffer error: %s", __func__, ssh_err(r));
342
343 sshbuf_free(msg);
344 free(signature);
345 }
346
347 /* shared */
348 static void
process_remove_identity(SocketEntry * e)349 process_remove_identity(SocketEntry *e)
350 {
351 int r, success = 0;
352 struct sshkey *key = NULL;
353 Identity *id;
354
355 if ((r = sshkey_froms(e->request, &key)) != 0) {
356 error("%s: get key: %s", __func__, ssh_err(r));
357 goto done;
358 }
359 if ((id = lookup_identity(key)) == NULL) {
360 debug("%s: key not found", __func__);
361 goto done;
362 }
363 /* We have this key, free it. */
364 if (idtab->nentries < 1)
365 fatal("%s: internal error: nentries %d",
366 __func__, idtab->nentries);
367 TAILQ_REMOVE(&idtab->idlist, id, next);
368 free_identity(id);
369 idtab->nentries--;
370 sshkey_free(key);
371 success = 1;
372 done:
373 send_status(e, success);
374 }
375
376 static void
process_remove_all_identities(SocketEntry * e)377 process_remove_all_identities(SocketEntry *e)
378 {
379 Identity *id;
380
381 /* Loop over all identities and clear the keys. */
382 for (id = TAILQ_FIRST(&idtab->idlist); id;
383 id = TAILQ_FIRST(&idtab->idlist)) {
384 TAILQ_REMOVE(&idtab->idlist, id, next);
385 free_identity(id);
386 }
387
388 /* Mark that there are no identities. */
389 idtab->nentries = 0;
390
391 /* Send success. */
392 send_status(e, 1);
393 }
394
395 /* removes expired keys and returns number of seconds until the next expiry */
396 static time_t
reaper(void)397 reaper(void)
398 {
399 time_t deadline = 0, now = monotime();
400 Identity *id, *nxt;
401
402 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
403 nxt = TAILQ_NEXT(id, next);
404 if (id->death == 0)
405 continue;
406 if (now >= id->death) {
407 debug("expiring key '%s'", id->comment);
408 TAILQ_REMOVE(&idtab->idlist, id, next);
409 free_identity(id);
410 idtab->nentries--;
411 } else
412 deadline = (deadline == 0) ? id->death :
413 MINIMUM(deadline, id->death);
414 }
415 if (deadline == 0 || deadline <= now)
416 return 0;
417 else
418 return (deadline - now);
419 }
420
421 static void
process_add_identity(SocketEntry * e)422 process_add_identity(SocketEntry *e)
423 {
424 Identity *id;
425 int success = 0, confirm = 0;
426 u_int seconds, maxsign;
427 char *comment = NULL;
428 time_t death = 0;
429 struct sshkey *k = NULL;
430 u_char ctype;
431 int r = SSH_ERR_INTERNAL_ERROR;
432
433 if ((r = sshkey_private_deserialize(e->request, &k)) != 0 ||
434 k == NULL ||
435 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
436 error("%s: decode private key: %s", __func__, ssh_err(r));
437 goto err;
438 }
439
440 while (sshbuf_len(e->request)) {
441 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) {
442 error("%s: buffer error: %s", __func__, ssh_err(r));
443 goto err;
444 }
445 switch (ctype) {
446 case SSH_AGENT_CONSTRAIN_LIFETIME:
447 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
448 error("%s: bad lifetime constraint: %s",
449 __func__, ssh_err(r));
450 goto err;
451 }
452 death = monotime() + seconds;
453 break;
454 case SSH_AGENT_CONSTRAIN_CONFIRM:
455 confirm = 1;
456 break;
457 case SSH_AGENT_CONSTRAIN_MAXSIGN:
458 if ((r = sshbuf_get_u32(e->request, &maxsign)) != 0) {
459 error("%s: bad maxsign constraint: %s",
460 __func__, ssh_err(r));
461 goto err;
462 }
463 if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
464 error("%s: cannot enable maxsign: %s",
465 __func__, ssh_err(r));
466 goto err;
467 }
468 break;
469 default:
470 error("%s: Unknown constraint %d", __func__, ctype);
471 err:
472 sshbuf_reset(e->request);
473 free(comment);
474 sshkey_free(k);
475 goto send;
476 }
477 }
478
479 success = 1;
480 if (lifetime && !death)
481 death = monotime() + lifetime;
482 if ((id = lookup_identity(k)) == NULL) {
483 id = xcalloc(1, sizeof(Identity));
484 TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
485 /* Increment the number of identities. */
486 idtab->nentries++;
487 } else {
488 /* key state might have been updated */
489 sshkey_free(id->key);
490 free(id->comment);
491 }
492 id->key = k;
493 id->comment = comment;
494 id->death = death;
495 id->confirm = confirm;
496 send:
497 send_status(e, success);
498 }
499
500 /* XXX todo: encrypt sensitive data with passphrase */
501 static void
process_lock_agent(SocketEntry * e,int lock)502 process_lock_agent(SocketEntry *e, int lock)
503 {
504 int r, success = 0, delay;
505 char *passwd;
506 u_char passwdhash[LOCK_SIZE];
507 static u_int fail_count = 0;
508 size_t pwlen;
509
510 /*
511 * This is deliberately fatal: the user has requested that we lock,
512 * but we can't parse their request properly. The only safe thing to
513 * do is abort.
514 */
515 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
516 fatal("%s: buffer error: %s", __func__, ssh_err(r));
517 if (pwlen == 0) {
518 debug("empty password not supported");
519 } else if (locked && !lock) {
520 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
521 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
522 fatal("bcrypt_pbkdf");
523 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
524 debug("agent unlocked");
525 locked = 0;
526 fail_count = 0;
527 explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
528 success = 1;
529 } else {
530 /* delay in 0.1s increments up to 10s */
531 if (fail_count < 100)
532 fail_count++;
533 delay = 100000 * fail_count;
534 debug("unlock failed, delaying %0.1lf seconds",
535 (double)delay/1000000);
536 usleep(delay);
537 }
538 explicit_bzero(passwdhash, sizeof(passwdhash));
539 } else if (!locked && lock) {
540 debug("agent locked");
541 locked = 1;
542 arc4random_buf(lock_salt, sizeof(lock_salt));
543 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
544 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
545 fatal("bcrypt_pbkdf");
546 success = 1;
547 }
548 explicit_bzero(passwd, pwlen);
549 free(passwd);
550 send_status(e, success);
551 }
552
553 static void
no_identities(SocketEntry * e)554 no_identities(SocketEntry *e)
555 {
556 struct sshbuf *msg;
557 int r;
558
559 if ((msg = sshbuf_new()) == NULL)
560 fatal("%s: sshbuf_new failed", __func__);
561 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
562 (r = sshbuf_put_u32(msg, 0)) != 0 ||
563 (r = sshbuf_put_stringb(e->output, msg)) != 0)
564 fatal("%s: buffer error: %s", __func__, ssh_err(r));
565 sshbuf_free(msg);
566 }
567
568 #ifdef ENABLE_PKCS11
569 static void
process_add_smartcard_key(SocketEntry * e)570 process_add_smartcard_key(SocketEntry *e)
571 {
572 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
573 int r, i, count = 0, success = 0, confirm = 0;
574 u_int seconds;
575 time_t death = 0;
576 u_char type;
577 struct sshkey **keys = NULL, *k;
578 Identity *id;
579
580 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
581 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
582 error("%s: buffer error: %s", __func__, ssh_err(r));
583 goto send;
584 }
585
586 while (sshbuf_len(e->request)) {
587 if ((r = sshbuf_get_u8(e->request, &type)) != 0) {
588 error("%s: buffer error: %s", __func__, ssh_err(r));
589 goto send;
590 }
591 switch (type) {
592 case SSH_AGENT_CONSTRAIN_LIFETIME:
593 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
594 error("%s: buffer error: %s",
595 __func__, ssh_err(r));
596 goto send;
597 }
598 death = monotime() + seconds;
599 break;
600 case SSH_AGENT_CONSTRAIN_CONFIRM:
601 confirm = 1;
602 break;
603 default:
604 error("%s: Unknown constraint type %d", __func__, type);
605 goto send;
606 }
607 }
608 if (realpath(provider, canonical_provider) == NULL) {
609 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
610 provider, strerror(errno));
611 goto send;
612 }
613 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) {
614 verbose("refusing PKCS#11 add of \"%.100s\": "
615 "provider not whitelisted", canonical_provider);
616 goto send;
617 }
618 debug("%s: add %.100s", __func__, canonical_provider);
619 if (lifetime && !death)
620 death = monotime() + lifetime;
621
622 count = pkcs11_add_provider(canonical_provider, pin, &keys);
623 for (i = 0; i < count; i++) {
624 k = keys[i];
625 if (lookup_identity(k) == NULL) {
626 id = xcalloc(1, sizeof(Identity));
627 id->key = k;
628 id->provider = xstrdup(canonical_provider);
629 id->comment = xstrdup(canonical_provider); /* XXX */
630 id->death = death;
631 id->confirm = confirm;
632 TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
633 idtab->nentries++;
634 success = 1;
635 } else {
636 sshkey_free(k);
637 }
638 keys[i] = NULL;
639 }
640 send:
641 free(pin);
642 free(provider);
643 free(keys);
644 send_status(e, success);
645 }
646
647 static void
process_remove_smartcard_key(SocketEntry * e)648 process_remove_smartcard_key(SocketEntry *e)
649 {
650 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
651 int r, success = 0;
652 Identity *id, *nxt;
653
654 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
655 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
656 error("%s: buffer error: %s", __func__, ssh_err(r));
657 goto send;
658 }
659 free(pin);
660
661 if (realpath(provider, canonical_provider) == NULL) {
662 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
663 provider, strerror(errno));
664 goto send;
665 }
666
667 debug("%s: remove %.100s", __func__, canonical_provider);
668 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
669 nxt = TAILQ_NEXT(id, next);
670 /* Skip file--based keys */
671 if (id->provider == NULL)
672 continue;
673 if (!strcmp(canonical_provider, id->provider)) {
674 TAILQ_REMOVE(&idtab->idlist, id, next);
675 free_identity(id);
676 idtab->nentries--;
677 }
678 }
679 if (pkcs11_del_provider(canonical_provider) == 0)
680 success = 1;
681 else
682 error("%s: pkcs11_del_provider failed", __func__);
683 send:
684 free(provider);
685 send_status(e, success);
686 }
687 #endif /* ENABLE_PKCS11 */
688
689 /* dispatch incoming messages */
690
691 static int
process_message(u_int socknum)692 process_message(u_int socknum)
693 {
694 u_int msg_len;
695 u_char type;
696 const u_char *cp;
697 int r;
698 SocketEntry *e;
699
700 if (socknum >= sockets_alloc) {
701 fatal("%s: socket number %u >= allocated %u",
702 __func__, socknum, sockets_alloc);
703 }
704 e = &sockets[socknum];
705
706 if (sshbuf_len(e->input) < 5)
707 return 0; /* Incomplete message header. */
708 cp = sshbuf_ptr(e->input);
709 msg_len = PEEK_U32(cp);
710 if (msg_len > AGENT_MAX_LEN) {
711 debug("%s: socket %u (fd=%d) message too long %u > %u",
712 __func__, socknum, e->fd, msg_len, AGENT_MAX_LEN);
713 return -1;
714 }
715 if (sshbuf_len(e->input) < msg_len + 4)
716 return 0; /* Incomplete message body. */
717
718 /* move the current input to e->request */
719 sshbuf_reset(e->request);
720 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
721 (r = sshbuf_get_u8(e->request, &type)) != 0) {
722 if (r == SSH_ERR_MESSAGE_INCOMPLETE ||
723 r == SSH_ERR_STRING_TOO_LARGE) {
724 debug("%s: buffer error: %s", __func__, ssh_err(r));
725 return -1;
726 }
727 fatal("%s: buffer error: %s", __func__, ssh_err(r));
728 }
729
730 debug("%s: socket %u (fd=%d) type %d", __func__, socknum, e->fd, type);
731
732 /* check whether agent is locked */
733 if (locked && type != SSH_AGENTC_UNLOCK) {
734 sshbuf_reset(e->request);
735 switch (type) {
736 case SSH2_AGENTC_REQUEST_IDENTITIES:
737 /* send empty lists */
738 no_identities(e);
739 break;
740 default:
741 /* send a fail message for all other request types */
742 send_status(e, 0);
743 }
744 return 0;
745 }
746
747 switch (type) {
748 case SSH_AGENTC_LOCK:
749 case SSH_AGENTC_UNLOCK:
750 process_lock_agent(e, type == SSH_AGENTC_LOCK);
751 break;
752 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
753 process_remove_all_identities(e); /* safe for !WITH_SSH1 */
754 break;
755 /* ssh2 */
756 case SSH2_AGENTC_SIGN_REQUEST:
757 process_sign_request2(e);
758 break;
759 case SSH2_AGENTC_REQUEST_IDENTITIES:
760 process_request_identities(e);
761 break;
762 case SSH2_AGENTC_ADD_IDENTITY:
763 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
764 process_add_identity(e);
765 break;
766 case SSH2_AGENTC_REMOVE_IDENTITY:
767 process_remove_identity(e);
768 break;
769 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
770 process_remove_all_identities(e);
771 break;
772 #ifdef ENABLE_PKCS11
773 case SSH_AGENTC_ADD_SMARTCARD_KEY:
774 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
775 process_add_smartcard_key(e);
776 break;
777 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
778 process_remove_smartcard_key(e);
779 break;
780 #endif /* ENABLE_PKCS11 */
781 default:
782 /* Unknown message. Respond with failure. */
783 error("Unknown message %d", type);
784 sshbuf_reset(e->request);
785 send_status(e, 0);
786 break;
787 }
788 return 0;
789 }
790
791 static void
new_socket(sock_type type,int fd)792 new_socket(sock_type type, int fd)
793 {
794 u_int i, old_alloc, new_alloc;
795
796 if (type == AUTH_CONNECTION) {
797 debug("xcount %d -> %d", xcount, xcount + 1);
798 ++xcount;
799 }
800 set_nonblock(fd);
801
802 if (fd > max_fd)
803 max_fd = fd;
804
805 for (i = 0; i < sockets_alloc; i++)
806 if (sockets[i].type == AUTH_UNUSED) {
807 sockets[i].fd = fd;
808 if ((sockets[i].input = sshbuf_new()) == NULL)
809 fatal("%s: sshbuf_new failed", __func__);
810 if ((sockets[i].output = sshbuf_new()) == NULL)
811 fatal("%s: sshbuf_new failed", __func__);
812 if ((sockets[i].request = sshbuf_new()) == NULL)
813 fatal("%s: sshbuf_new failed", __func__);
814 sockets[i].type = type;
815 return;
816 }
817 old_alloc = sockets_alloc;
818 new_alloc = sockets_alloc + 10;
819 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0]));
820 for (i = old_alloc; i < new_alloc; i++)
821 sockets[i].type = AUTH_UNUSED;
822 sockets_alloc = new_alloc;
823 sockets[old_alloc].fd = fd;
824 if ((sockets[old_alloc].input = sshbuf_new()) == NULL)
825 fatal("%s: sshbuf_new failed", __func__);
826 if ((sockets[old_alloc].output = sshbuf_new()) == NULL)
827 fatal("%s: sshbuf_new failed", __func__);
828 if ((sockets[old_alloc].request = sshbuf_new()) == NULL)
829 fatal("%s: sshbuf_new failed", __func__);
830 sockets[old_alloc].type = type;
831 }
832
833 static int
handle_socket_read(u_int socknum)834 handle_socket_read(u_int socknum)
835 {
836 struct sockaddr_un sunaddr;
837 socklen_t slen;
838 uid_t euid;
839 gid_t egid;
840 int fd;
841
842 slen = sizeof(sunaddr);
843 fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen);
844 if (fd < 0) {
845 error("accept from AUTH_SOCKET: %s", strerror(errno));
846 return -1;
847 }
848 if (getpeereid(fd, &euid, &egid) < 0) {
849 error("getpeereid %d failed: %s", fd, strerror(errno));
850 close(fd);
851 return -1;
852 }
853 if ((euid != 0) && (getuid() != euid)) {
854 error("uid mismatch: peer euid %u != uid %u",
855 (u_int) euid, (u_int) getuid());
856 close(fd);
857 return -1;
858 }
859 new_socket(AUTH_CONNECTION, fd);
860 return 0;
861 }
862
863 static int
handle_conn_read(u_int socknum)864 handle_conn_read(u_int socknum)
865 {
866 char buf[1024];
867 ssize_t len;
868 int r;
869
870 if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) {
871 if (len == -1) {
872 if (errno == EAGAIN || errno == EINTR)
873 return 0;
874 error("%s: read error on socket %u (fd %d): %s",
875 __func__, socknum, sockets[socknum].fd,
876 strerror(errno));
877 }
878 return -1;
879 }
880 if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0)
881 fatal("%s: buffer error: %s", __func__, ssh_err(r));
882 explicit_bzero(buf, sizeof(buf));
883 process_message(socknum);
884 return 0;
885 }
886
887 static int
handle_conn_write(u_int socknum)888 handle_conn_write(u_int socknum)
889 {
890 ssize_t len;
891 int r;
892
893 if (sshbuf_len(sockets[socknum].output) == 0)
894 return 0; /* shouldn't happen */
895 if ((len = write(sockets[socknum].fd,
896 sshbuf_ptr(sockets[socknum].output),
897 sshbuf_len(sockets[socknum].output))) <= 0) {
898 if (len == -1) {
899 if (errno == EAGAIN || errno == EINTR)
900 return 0;
901 error("%s: read error on socket %u (fd %d): %s",
902 __func__, socknum, sockets[socknum].fd,
903 strerror(errno));
904 }
905 return -1;
906 }
907 if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0)
908 fatal("%s: buffer error: %s", __func__, ssh_err(r));
909 return 0;
910 }
911
912 static void
after_poll(struct pollfd * pfd,size_t npfd,u_int maxfds)913 after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds)
914 {
915 size_t i;
916 u_int socknum, activefds = npfd;
917
918 for (i = 0; i < npfd; i++) {
919 if (pfd[i].revents == 0)
920 continue;
921 /* Find sockets entry */
922 for (socknum = 0; socknum < sockets_alloc; socknum++) {
923 if (sockets[socknum].type != AUTH_SOCKET &&
924 sockets[socknum].type != AUTH_CONNECTION)
925 continue;
926 if (pfd[i].fd == sockets[socknum].fd)
927 break;
928 }
929 if (socknum >= sockets_alloc) {
930 error("%s: no socket for fd %d", __func__, pfd[i].fd);
931 continue;
932 }
933 /* Process events */
934 switch (sockets[socknum].type) {
935 case AUTH_SOCKET:
936 if ((pfd[i].revents & (POLLIN|POLLERR)) == 0)
937 break;
938 if (npfd > maxfds) {
939 debug3("out of fds (active %u >= limit %u); "
940 "skipping accept", activefds, maxfds);
941 break;
942 }
943 if (handle_socket_read(socknum) == 0)
944 activefds++;
945 break;
946 case AUTH_CONNECTION:
947 if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 &&
948 handle_conn_read(socknum) != 0) {
949 goto close_sock;
950 }
951 if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 &&
952 handle_conn_write(socknum) != 0) {
953 close_sock:
954 if (activefds == 0)
955 fatal("activefds == 0 at close_sock");
956 close_socket(&sockets[socknum]);
957 activefds--;
958 break;
959 }
960 break;
961 default:
962 break;
963 }
964 }
965 }
966
967 static int
prepare_poll(struct pollfd ** pfdp,size_t * npfdp,int * timeoutp,u_int maxfds)968 prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds)
969 {
970 struct pollfd *pfd = *pfdp;
971 size_t i, j, npfd = 0;
972 time_t deadline;
973
974 /* Count active sockets */
975 for (i = 0; i < sockets_alloc; i++) {
976 switch (sockets[i].type) {
977 case AUTH_SOCKET:
978 case AUTH_CONNECTION:
979 npfd++;
980 break;
981 case AUTH_UNUSED:
982 break;
983 default:
984 fatal("Unknown socket type %d", sockets[i].type);
985 break;
986 }
987 }
988 if (npfd != *npfdp &&
989 (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL)
990 fatal("%s: recallocarray failed", __func__);
991 *pfdp = pfd;
992 *npfdp = npfd;
993
994 for (i = j = 0; i < sockets_alloc; i++) {
995 switch (sockets[i].type) {
996 case AUTH_SOCKET:
997 if (npfd > maxfds) {
998 debug3("out of fds (active %zu >= limit %u); "
999 "skipping arming listener", npfd, maxfds);
1000 break;
1001 }
1002 pfd[j].fd = sockets[i].fd;
1003 pfd[j].revents = 0;
1004 pfd[j].events = POLLIN;
1005 j++;
1006 break;
1007 case AUTH_CONNECTION:
1008 pfd[j].fd = sockets[i].fd;
1009 pfd[j].revents = 0;
1010 /* XXX backoff when input buffer full */
1011 pfd[j].events = POLLIN;
1012 if (sshbuf_len(sockets[i].output) > 0)
1013 pfd[j].events |= POLLOUT;
1014 j++;
1015 break;
1016 default:
1017 break;
1018 }
1019 }
1020 deadline = reaper();
1021 if (parent_alive_interval != 0)
1022 deadline = (deadline == 0) ? parent_alive_interval :
1023 MINIMUM(deadline, parent_alive_interval);
1024 if (deadline == 0) {
1025 *timeoutp = -1; /* INFTIM */
1026 } else {
1027 if (deadline > INT_MAX / 1000)
1028 *timeoutp = INT_MAX / 1000;
1029 else
1030 *timeoutp = deadline * 1000;
1031 }
1032 return (1);
1033 }
1034
1035 static void
cleanup_socket(void)1036 cleanup_socket(void)
1037 {
1038 if (cleanup_pid != 0 && getpid() != cleanup_pid)
1039 return;
1040 debug("%s: cleanup", __func__);
1041 if (socket_name[0])
1042 unlink(socket_name);
1043 if (socket_dir[0])
1044 rmdir(socket_dir);
1045 }
1046
1047 void
cleanup_exit(int i)1048 cleanup_exit(int i)
1049 {
1050 cleanup_socket();
1051 _exit(i);
1052 }
1053
1054 /*ARGSUSED*/
1055 static void
cleanup_handler(int sig)1056 cleanup_handler(int sig)
1057 {
1058 cleanup_socket();
1059 #ifdef ENABLE_PKCS11
1060 pkcs11_terminate();
1061 #endif
1062 _exit(2);
1063 }
1064
1065 static void
check_parent_exists(void)1066 check_parent_exists(void)
1067 {
1068 /*
1069 * If our parent has exited then getppid() will return (pid_t)1,
1070 * so testing for that should be safe.
1071 */
1072 if (parent_pid != -1 && getppid() != parent_pid) {
1073 /* printf("Parent has died - Authentication agent exiting.\n"); */
1074 cleanup_socket();
1075 _exit(2);
1076 }
1077 }
1078
1079 static void
usage(void)1080 usage(void)
1081 {
1082 fprintf(stderr,
1083 "usage: ssh-agent [-c | -s] [-Ddx] [-a bind_address] [-E fingerprint_hash]\n"
1084 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n"
1085 " ssh-agent [-c | -s] -k\n");
1086 exit(1);
1087 }
1088
1089 int
main(int ac,char ** av)1090 main(int ac, char **av)
1091 {
1092 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
1093 int sock, fd, ch, result, saved_errno;
1094 char *shell, *format, *pidstr, *agentsocket = NULL;
1095 #ifdef HAVE_SETRLIMIT
1096 struct rlimit rlim;
1097 #endif
1098 extern int optind;
1099 extern char *optarg;
1100 pid_t pid;
1101 char pidstrbuf[1 + 3 * sizeof pid];
1102 size_t len;
1103 mode_t prev_mask;
1104 int timeout = -1; /* INFTIM */
1105 struct pollfd *pfd = NULL;
1106 size_t npfd = 0;
1107 u_int maxfds;
1108
1109 ssh_malloc_init(); /* must be called before any mallocs */
1110 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1111 sanitise_stdfd();
1112
1113 /* drop */
1114 setegid(getgid());
1115 setgid(getgid());
1116 setuid(geteuid());
1117
1118 platform_disable_tracing(0); /* strict=no */
1119
1120 if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
1121 fatal("%s: getrlimit: %s", __progname, strerror(errno));
1122
1123 #ifdef WITH_OPENSSL
1124 OpenSSL_add_all_algorithms();
1125 #endif
1126
1127 __progname = ssh_get_progname(av[0]);
1128 seed_rng();
1129
1130 while ((ch = getopt(ac, av, "cDdksE:a:P:t:x")) != -1) {
1131 switch (ch) {
1132 case 'E':
1133 fingerprint_hash = ssh_digest_alg_by_name(optarg);
1134 if (fingerprint_hash == -1)
1135 fatal("Invalid hash algorithm \"%s\"", optarg);
1136 break;
1137 case 'c':
1138 if (s_flag)
1139 usage();
1140 c_flag++;
1141 break;
1142 case 'k':
1143 k_flag++;
1144 break;
1145 case 'P':
1146 if (pkcs11_whitelist != NULL)
1147 fatal("-P option already specified");
1148 pkcs11_whitelist = xstrdup(optarg);
1149 break;
1150 case 's':
1151 if (c_flag)
1152 usage();
1153 s_flag++;
1154 break;
1155 case 'd':
1156 if (d_flag || D_flag)
1157 usage();
1158 d_flag++;
1159 break;
1160 case 'D':
1161 if (d_flag || D_flag)
1162 usage();
1163 D_flag++;
1164 break;
1165 case 'a':
1166 agentsocket = optarg;
1167 break;
1168 case 't':
1169 if ((lifetime = convtime(optarg)) == -1) {
1170 fprintf(stderr, "Invalid lifetime\n");
1171 usage();
1172 }
1173 break;
1174 case 'x':
1175 xcount = 0;
1176 break;
1177 default:
1178 usage();
1179 }
1180 }
1181 ac -= optind;
1182 av += optind;
1183
1184 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
1185 usage();
1186
1187 if (pkcs11_whitelist == NULL)
1188 pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST);
1189
1190 if (ac == 0 && !c_flag && !s_flag) {
1191 shell = getenv("SHELL");
1192 if (shell != NULL && (len = strlen(shell)) > 2 &&
1193 strncmp(shell + len - 3, "csh", 3) == 0)
1194 c_flag = 1;
1195 }
1196 if (k_flag) {
1197 const char *errstr = NULL;
1198
1199 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1200 if (pidstr == NULL) {
1201 fprintf(stderr, "%s not set, cannot kill agent\n",
1202 SSH_AGENTPID_ENV_NAME);
1203 exit(1);
1204 }
1205 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1206 if (errstr) {
1207 fprintf(stderr,
1208 "%s=\"%s\", which is not a good PID: %s\n",
1209 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1210 exit(1);
1211 }
1212 if (kill(pid, SIGTERM) == -1) {
1213 perror("kill");
1214 exit(1);
1215 }
1216 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1217 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1218 printf(format, SSH_AGENTPID_ENV_NAME);
1219 printf("echo Agent pid %ld killed;\n", (long)pid);
1220 exit(0);
1221 }
1222
1223 /*
1224 * Minimum file descriptors:
1225 * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) +
1226 * a few spare for libc / stack protectors / sanitisers, etc.
1227 */
1228 #define SSH_AGENT_MIN_FDS (3+1+1+1+4)
1229 if (rlim.rlim_cur < SSH_AGENT_MIN_FDS)
1230 fatal("%s: file descriptior rlimit %lld too low (minimum %u)",
1231 __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS);
1232 maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS;
1233
1234 parent_pid = getpid();
1235
1236 if (agentsocket == NULL) {
1237 /* Create private directory for agent socket */
1238 mktemp_proto(socket_dir, sizeof(socket_dir));
1239 if (mkdtemp(socket_dir) == NULL) {
1240 perror("mkdtemp: private socket dir");
1241 exit(1);
1242 }
1243 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1244 (long)parent_pid);
1245 } else {
1246 /* Try to use specified agent socket */
1247 socket_dir[0] = '\0';
1248 strlcpy(socket_name, agentsocket, sizeof socket_name);
1249 }
1250
1251 /*
1252 * Create socket early so it will exist before command gets run from
1253 * the parent.
1254 */
1255 prev_mask = umask(0177);
1256 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
1257 if (sock < 0) {
1258 /* XXX - unix_listener() calls error() not perror() */
1259 *socket_name = '\0'; /* Don't unlink any existing file */
1260 cleanup_exit(1);
1261 }
1262 umask(prev_mask);
1263
1264 /*
1265 * Fork, and have the parent execute the command, if any, or present
1266 * the socket data. The child continues as the authentication agent.
1267 */
1268 if (D_flag || d_flag) {
1269 log_init(__progname,
1270 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
1271 SYSLOG_FACILITY_AUTH, 1);
1272 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1273 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1274 SSH_AUTHSOCKET_ENV_NAME);
1275 printf("echo Agent pid %ld;\n", (long)parent_pid);
1276 fflush(stdout);
1277 goto skip;
1278 }
1279 pid = fork();
1280 if (pid == -1) {
1281 perror("fork");
1282 cleanup_exit(1);
1283 }
1284 if (pid != 0) { /* Parent - execute the given command. */
1285 close(sock);
1286 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1287 if (ac == 0) {
1288 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1289 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1290 SSH_AUTHSOCKET_ENV_NAME);
1291 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1292 SSH_AGENTPID_ENV_NAME);
1293 printf("echo Agent pid %ld;\n", (long)pid);
1294 exit(0);
1295 }
1296 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1297 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1298 perror("setenv");
1299 exit(1);
1300 }
1301 execvp(av[0], av);
1302 perror(av[0]);
1303 exit(1);
1304 }
1305 /* child */
1306 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1307
1308 if (setsid() == -1) {
1309 error("setsid: %s", strerror(errno));
1310 cleanup_exit(1);
1311 }
1312
1313 (void)chdir("/");
1314 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1315 /* XXX might close listen socket */
1316 (void)dup2(fd, STDIN_FILENO);
1317 (void)dup2(fd, STDOUT_FILENO);
1318 (void)dup2(fd, STDERR_FILENO);
1319 if (fd > 2)
1320 close(fd);
1321 }
1322
1323 #ifdef HAVE_SETRLIMIT
1324 /* deny core dumps, since memory contains unencrypted private keys */
1325 rlim.rlim_cur = rlim.rlim_max = 0;
1326 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1327 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1328 cleanup_exit(1);
1329 }
1330 #endif
1331
1332 skip:
1333
1334 cleanup_pid = getpid();
1335
1336 #ifdef ENABLE_PKCS11
1337 pkcs11_init(0);
1338 #endif
1339 new_socket(AUTH_SOCKET, sock);
1340 if (ac > 0)
1341 parent_alive_interval = 10;
1342 idtab_init();
1343 signal(SIGPIPE, SIG_IGN);
1344 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
1345 signal(SIGHUP, cleanup_handler);
1346 signal(SIGTERM, cleanup_handler);
1347
1348 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
1349 fatal("%s: pledge: %s", __progname, strerror(errno));
1350 platform_pledge_agent();
1351
1352 while (1) {
1353 prepare_poll(&pfd, &npfd, &timeout, maxfds);
1354 result = poll(pfd, npfd, timeout);
1355 saved_errno = errno;
1356 if (parent_alive_interval != 0)
1357 check_parent_exists();
1358 (void) reaper(); /* remove expired keys */
1359 if (result < 0) {
1360 if (saved_errno == EINTR)
1361 continue;
1362 fatal("poll: %s", strerror(saved_errno));
1363 } else if (result > 0)
1364 after_poll(pfd, npfd, maxfds);
1365 }
1366 /* NOTREACHED */
1367 }
1368