xref: /freebsd/crypto/openssh/ssh-agent.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
1 /* $OpenBSD: ssh-agent.c,v 1.171 2010/11/21 01:01:13 djm Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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 #include <openssl/evp.h>
54 #include <openssl/md5.h>
55 #include "openbsd-compat/openssl-compat.h"
56 
57 #include <errno.h>
58 #include <fcntl.h>
59 #ifdef HAVE_PATHS_H
60 # include <paths.h>
61 #endif
62 #include <signal.h>
63 #include <stdarg.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <time.h>
67 #include <string.h>
68 #include <unistd.h>
69 
70 #include "xmalloc.h"
71 #include "ssh.h"
72 #include "rsa.h"
73 #include "buffer.h"
74 #include "key.h"
75 #include "authfd.h"
76 #include "compat.h"
77 #include "log.h"
78 #include "misc.h"
79 
80 #ifdef ENABLE_PKCS11
81 #include "ssh-pkcs11.h"
82 #endif
83 
84 #if defined(HAVE_SYS_PRCTL_H)
85 #include <sys/prctl.h>	/* For prctl() and PR_SET_DUMPABLE */
86 #endif
87 
88 typedef enum {
89 	AUTH_UNUSED,
90 	AUTH_SOCKET,
91 	AUTH_CONNECTION
92 } sock_type;
93 
94 typedef struct {
95 	int fd;
96 	sock_type type;
97 	Buffer input;
98 	Buffer output;
99 	Buffer request;
100 } SocketEntry;
101 
102 u_int sockets_alloc = 0;
103 SocketEntry *sockets = NULL;
104 
105 typedef struct identity {
106 	TAILQ_ENTRY(identity) next;
107 	Key *key;
108 	char *comment;
109 	char *provider;
110 	u_int death;
111 	u_int confirm;
112 } Identity;
113 
114 typedef struct {
115 	int nentries;
116 	TAILQ_HEAD(idqueue, identity) idlist;
117 } Idtab;
118 
119 /* private key table, one per protocol version */
120 Idtab idtable[3];
121 
122 int max_fd = 0;
123 
124 /* pid of shell == parent of agent */
125 pid_t parent_pid = -1;
126 u_int parent_alive_interval = 0;
127 
128 /* pathname and directory for AUTH_SOCKET */
129 char socket_name[MAXPATHLEN];
130 char socket_dir[MAXPATHLEN];
131 
132 /* locking */
133 int locked = 0;
134 char *lock_passwd = NULL;
135 
136 extern char *__progname;
137 
138 /* Default lifetime (0 == forever) */
139 static int lifetime = 0;
140 
141 static void
142 close_socket(SocketEntry *e)
143 {
144 	close(e->fd);
145 	e->fd = -1;
146 	e->type = AUTH_UNUSED;
147 	buffer_free(&e->input);
148 	buffer_free(&e->output);
149 	buffer_free(&e->request);
150 }
151 
152 static void
153 idtab_init(void)
154 {
155 	int i;
156 
157 	for (i = 0; i <=2; i++) {
158 		TAILQ_INIT(&idtable[i].idlist);
159 		idtable[i].nentries = 0;
160 	}
161 }
162 
163 /* return private key table for requested protocol version */
164 static Idtab *
165 idtab_lookup(int version)
166 {
167 	if (version < 1 || version > 2)
168 		fatal("internal error, bad protocol version %d", version);
169 	return &idtable[version];
170 }
171 
172 static void
173 free_identity(Identity *id)
174 {
175 	key_free(id->key);
176 	if (id->provider != NULL)
177 		xfree(id->provider);
178 	xfree(id->comment);
179 	xfree(id);
180 }
181 
182 /* return matching private key for given public key */
183 static Identity *
184 lookup_identity(Key *key, int version)
185 {
186 	Identity *id;
187 
188 	Idtab *tab = idtab_lookup(version);
189 	TAILQ_FOREACH(id, &tab->idlist, next) {
190 		if (key_equal(key, id->key))
191 			return (id);
192 	}
193 	return (NULL);
194 }
195 
196 /* Check confirmation of keysign request */
197 static int
198 confirm_key(Identity *id)
199 {
200 	char *p;
201 	int ret = -1;
202 
203 	p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
204 	if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
205 	    id->comment, p))
206 		ret = 0;
207 	xfree(p);
208 
209 	return (ret);
210 }
211 
212 /* send list of supported public keys to 'client' */
213 static void
214 process_request_identities(SocketEntry *e, int version)
215 {
216 	Idtab *tab = idtab_lookup(version);
217 	Identity *id;
218 	Buffer msg;
219 
220 	buffer_init(&msg);
221 	buffer_put_char(&msg, (version == 1) ?
222 	    SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
223 	buffer_put_int(&msg, tab->nentries);
224 	TAILQ_FOREACH(id, &tab->idlist, next) {
225 		if (id->key->type == KEY_RSA1) {
226 			buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
227 			buffer_put_bignum(&msg, id->key->rsa->e);
228 			buffer_put_bignum(&msg, id->key->rsa->n);
229 		} else {
230 			u_char *blob;
231 			u_int blen;
232 			key_to_blob(id->key, &blob, &blen);
233 			buffer_put_string(&msg, blob, blen);
234 			xfree(blob);
235 		}
236 		buffer_put_cstring(&msg, id->comment);
237 	}
238 	buffer_put_int(&e->output, buffer_len(&msg));
239 	buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
240 	buffer_free(&msg);
241 }
242 
243 /* ssh1 only */
244 static void
245 process_authentication_challenge1(SocketEntry *e)
246 {
247 	u_char buf[32], mdbuf[16], session_id[16];
248 	u_int response_type;
249 	BIGNUM *challenge;
250 	Identity *id;
251 	int i, len;
252 	Buffer msg;
253 	MD5_CTX md;
254 	Key *key;
255 
256 	buffer_init(&msg);
257 	key = key_new(KEY_RSA1);
258 	if ((challenge = BN_new()) == NULL)
259 		fatal("process_authentication_challenge1: BN_new failed");
260 
261 	(void) buffer_get_int(&e->request);			/* ignored */
262 	buffer_get_bignum(&e->request, key->rsa->e);
263 	buffer_get_bignum(&e->request, key->rsa->n);
264 	buffer_get_bignum(&e->request, challenge);
265 
266 	/* Only protocol 1.1 is supported */
267 	if (buffer_len(&e->request) == 0)
268 		goto failure;
269 	buffer_get(&e->request, session_id, 16);
270 	response_type = buffer_get_int(&e->request);
271 	if (response_type != 1)
272 		goto failure;
273 
274 	id = lookup_identity(key, 1);
275 	if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
276 		Key *private = id->key;
277 		/* Decrypt the challenge using the private key. */
278 		if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
279 			goto failure;
280 
281 		/* The response is MD5 of decrypted challenge plus session id. */
282 		len = BN_num_bytes(challenge);
283 		if (len <= 0 || len > 32) {
284 			logit("process_authentication_challenge: bad challenge length %d", len);
285 			goto failure;
286 		}
287 		memset(buf, 0, 32);
288 		BN_bn2bin(challenge, buf + 32 - len);
289 		MD5_Init(&md);
290 		MD5_Update(&md, buf, 32);
291 		MD5_Update(&md, session_id, 16);
292 		MD5_Final(mdbuf, &md);
293 
294 		/* Send the response. */
295 		buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
296 		for (i = 0; i < 16; i++)
297 			buffer_put_char(&msg, mdbuf[i]);
298 		goto send;
299 	}
300 
301 failure:
302 	/* Unknown identity or protocol error.  Send failure. */
303 	buffer_put_char(&msg, SSH_AGENT_FAILURE);
304 send:
305 	buffer_put_int(&e->output, buffer_len(&msg));
306 	buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
307 	key_free(key);
308 	BN_clear_free(challenge);
309 	buffer_free(&msg);
310 }
311 
312 /* ssh2 only */
313 static void
314 process_sign_request2(SocketEntry *e)
315 {
316 	u_char *blob, *data, *signature = NULL;
317 	u_int blen, dlen, slen = 0;
318 	extern int datafellows;
319 	int odatafellows;
320 	int ok = -1, flags;
321 	Buffer msg;
322 	Key *key;
323 
324 	datafellows = 0;
325 
326 	blob = buffer_get_string(&e->request, &blen);
327 	data = buffer_get_string(&e->request, &dlen);
328 
329 	flags = buffer_get_int(&e->request);
330 	odatafellows = datafellows;
331 	if (flags & SSH_AGENT_OLD_SIGNATURE)
332 		datafellows = SSH_BUG_SIGBLOB;
333 
334 	key = key_from_blob(blob, blen);
335 	if (key != NULL) {
336 		Identity *id = lookup_identity(key, 2);
337 		if (id != NULL && (!id->confirm || confirm_key(id) == 0))
338 			ok = key_sign(id->key, &signature, &slen, data, dlen);
339 		key_free(key);
340 	}
341 	buffer_init(&msg);
342 	if (ok == 0) {
343 		buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
344 		buffer_put_string(&msg, signature, slen);
345 	} else {
346 		buffer_put_char(&msg, SSH_AGENT_FAILURE);
347 	}
348 	buffer_put_int(&e->output, buffer_len(&msg));
349 	buffer_append(&e->output, buffer_ptr(&msg),
350 	    buffer_len(&msg));
351 	buffer_free(&msg);
352 	xfree(data);
353 	xfree(blob);
354 	if (signature != NULL)
355 		xfree(signature);
356 	datafellows = odatafellows;
357 }
358 
359 /* shared */
360 static void
361 process_remove_identity(SocketEntry *e, int version)
362 {
363 	u_int blen, bits;
364 	int success = 0;
365 	Key *key = NULL;
366 	u_char *blob;
367 
368 	switch (version) {
369 	case 1:
370 		key = key_new(KEY_RSA1);
371 		bits = buffer_get_int(&e->request);
372 		buffer_get_bignum(&e->request, key->rsa->e);
373 		buffer_get_bignum(&e->request, key->rsa->n);
374 
375 		if (bits != key_size(key))
376 			logit("Warning: identity keysize mismatch: actual %u, announced %u",
377 			    key_size(key), bits);
378 		break;
379 	case 2:
380 		blob = buffer_get_string(&e->request, &blen);
381 		key = key_from_blob(blob, blen);
382 		xfree(blob);
383 		break;
384 	}
385 	if (key != NULL) {
386 		Identity *id = lookup_identity(key, version);
387 		if (id != NULL) {
388 			/*
389 			 * We have this key.  Free the old key.  Since we
390 			 * don't want to leave empty slots in the middle of
391 			 * the array, we actually free the key there and move
392 			 * all the entries between the empty slot and the end
393 			 * of the array.
394 			 */
395 			Idtab *tab = idtab_lookup(version);
396 			if (tab->nentries < 1)
397 				fatal("process_remove_identity: "
398 				    "internal error: tab->nentries %d",
399 				    tab->nentries);
400 			TAILQ_REMOVE(&tab->idlist, id, next);
401 			free_identity(id);
402 			tab->nentries--;
403 			success = 1;
404 		}
405 		key_free(key);
406 	}
407 	buffer_put_int(&e->output, 1);
408 	buffer_put_char(&e->output,
409 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
410 }
411 
412 static void
413 process_remove_all_identities(SocketEntry *e, int version)
414 {
415 	Idtab *tab = idtab_lookup(version);
416 	Identity *id;
417 
418 	/* Loop over all identities and clear the keys. */
419 	for (id = TAILQ_FIRST(&tab->idlist); id;
420 	    id = TAILQ_FIRST(&tab->idlist)) {
421 		TAILQ_REMOVE(&tab->idlist, id, next);
422 		free_identity(id);
423 	}
424 
425 	/* Mark that there are no identities. */
426 	tab->nentries = 0;
427 
428 	/* Send success. */
429 	buffer_put_int(&e->output, 1);
430 	buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
431 }
432 
433 /* removes expired keys and returns number of seconds until the next expiry */
434 static u_int
435 reaper(void)
436 {
437 	u_int deadline = 0, now = time(NULL);
438 	Identity *id, *nxt;
439 	int version;
440 	Idtab *tab;
441 
442 	for (version = 1; version < 3; version++) {
443 		tab = idtab_lookup(version);
444 		for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
445 			nxt = TAILQ_NEXT(id, next);
446 			if (id->death == 0)
447 				continue;
448 			if (now >= id->death) {
449 				debug("expiring key '%s'", id->comment);
450 				TAILQ_REMOVE(&tab->idlist, id, next);
451 				free_identity(id);
452 				tab->nentries--;
453 			} else
454 				deadline = (deadline == 0) ? id->death :
455 				    MIN(deadline, id->death);
456 		}
457 	}
458 	if (deadline == 0 || deadline <= now)
459 		return 0;
460 	else
461 		return (deadline - now);
462 }
463 
464 static void
465 process_add_identity(SocketEntry *e, int version)
466 {
467 	Idtab *tab = idtab_lookup(version);
468 	Identity *id;
469 	int type, success = 0, death = 0, confirm = 0;
470 	char *type_name, *comment;
471 	Key *k = NULL;
472 #ifdef OPENSSL_HAS_ECC
473 	BIGNUM *exponent;
474 	EC_POINT *q;
475 	char *curve;
476 #endif
477 	u_char *cert;
478 	u_int len;
479 
480 	switch (version) {
481 	case 1:
482 		k = key_new_private(KEY_RSA1);
483 		(void) buffer_get_int(&e->request);		/* ignored */
484 		buffer_get_bignum(&e->request, k->rsa->n);
485 		buffer_get_bignum(&e->request, k->rsa->e);
486 		buffer_get_bignum(&e->request, k->rsa->d);
487 		buffer_get_bignum(&e->request, k->rsa->iqmp);
488 
489 		/* SSH and SSL have p and q swapped */
490 		buffer_get_bignum(&e->request, k->rsa->q);	/* p */
491 		buffer_get_bignum(&e->request, k->rsa->p);	/* q */
492 
493 		/* Generate additional parameters */
494 		rsa_generate_additional_parameters(k->rsa);
495 		break;
496 	case 2:
497 		type_name = buffer_get_string(&e->request, NULL);
498 		type = key_type_from_name(type_name);
499 		switch (type) {
500 		case KEY_DSA:
501 			k = key_new_private(type);
502 			buffer_get_bignum2(&e->request, k->dsa->p);
503 			buffer_get_bignum2(&e->request, k->dsa->q);
504 			buffer_get_bignum2(&e->request, k->dsa->g);
505 			buffer_get_bignum2(&e->request, k->dsa->pub_key);
506 			buffer_get_bignum2(&e->request, k->dsa->priv_key);
507 			break;
508 		case KEY_DSA_CERT_V00:
509 		case KEY_DSA_CERT:
510 			cert = buffer_get_string(&e->request, &len);
511 			if ((k = key_from_blob(cert, len)) == NULL)
512 				fatal("Certificate parse failed");
513 			xfree(cert);
514 			key_add_private(k);
515 			buffer_get_bignum2(&e->request, k->dsa->priv_key);
516 			break;
517 #ifdef OPENSSL_HAS_ECC
518 		case KEY_ECDSA:
519 			k = key_new_private(type);
520 			k->ecdsa_nid = key_ecdsa_nid_from_name(type_name);
521 			curve = buffer_get_string(&e->request, NULL);
522 			if (k->ecdsa_nid != key_curve_name_to_nid(curve))
523 				fatal("%s: curve names mismatch", __func__);
524 			xfree(curve);
525 			k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
526 			if (k->ecdsa == NULL)
527 				fatal("%s: EC_KEY_new_by_curve_name failed",
528 				    __func__);
529 			q = EC_POINT_new(EC_KEY_get0_group(k->ecdsa));
530 			if (q == NULL)
531 				fatal("%s: BN_new failed", __func__);
532 			if ((exponent = BN_new()) == NULL)
533 				fatal("%s: BN_new failed", __func__);
534 			buffer_get_ecpoint(&e->request,
535 				EC_KEY_get0_group(k->ecdsa), q);
536 			buffer_get_bignum2(&e->request, exponent);
537 			if (EC_KEY_set_public_key(k->ecdsa, q) != 1)
538 				fatal("%s: EC_KEY_set_public_key failed",
539 				    __func__);
540 			if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1)
541 				fatal("%s: EC_KEY_set_private_key failed",
542 				    __func__);
543 			if (key_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
544 			    EC_KEY_get0_public_key(k->ecdsa)) != 0)
545 				fatal("%s: bad ECDSA public key", __func__);
546 			if (key_ec_validate_private(k->ecdsa) != 0)
547 				fatal("%s: bad ECDSA private key", __func__);
548 			BN_clear_free(exponent);
549 			EC_POINT_free(q);
550 			break;
551 		case KEY_ECDSA_CERT:
552 			cert = buffer_get_string(&e->request, &len);
553 			if ((k = key_from_blob(cert, len)) == NULL)
554 				fatal("Certificate parse failed");
555 			xfree(cert);
556 			key_add_private(k);
557 			if ((exponent = BN_new()) == NULL)
558 				fatal("%s: BN_new failed", __func__);
559 			buffer_get_bignum2(&e->request, exponent);
560 			if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1)
561 				fatal("%s: EC_KEY_set_private_key failed",
562 				    __func__);
563 			if (key_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
564 			    EC_KEY_get0_public_key(k->ecdsa)) != 0 ||
565 			    key_ec_validate_private(k->ecdsa) != 0)
566 				fatal("%s: bad ECDSA key", __func__);
567 			BN_clear_free(exponent);
568 			break;
569 #endif /* OPENSSL_HAS_ECC */
570 		case KEY_RSA:
571 			k = key_new_private(type);
572 			buffer_get_bignum2(&e->request, k->rsa->n);
573 			buffer_get_bignum2(&e->request, k->rsa->e);
574 			buffer_get_bignum2(&e->request, k->rsa->d);
575 			buffer_get_bignum2(&e->request, k->rsa->iqmp);
576 			buffer_get_bignum2(&e->request, k->rsa->p);
577 			buffer_get_bignum2(&e->request, k->rsa->q);
578 
579 			/* Generate additional parameters */
580 			rsa_generate_additional_parameters(k->rsa);
581 			break;
582 		case KEY_RSA_CERT_V00:
583 		case KEY_RSA_CERT:
584 			cert = buffer_get_string(&e->request, &len);
585 			if ((k = key_from_blob(cert, len)) == NULL)
586 				fatal("Certificate parse failed");
587 			xfree(cert);
588 			key_add_private(k);
589 			buffer_get_bignum2(&e->request, k->rsa->d);
590 			buffer_get_bignum2(&e->request, k->rsa->iqmp);
591 			buffer_get_bignum2(&e->request, k->rsa->p);
592 			buffer_get_bignum2(&e->request, k->rsa->q);
593 			break;
594 		default:
595 			xfree(type_name);
596 			buffer_clear(&e->request);
597 			goto send;
598 		}
599 		xfree(type_name);
600 		break;
601 	}
602 	/* enable blinding */
603 	switch (k->type) {
604 	case KEY_RSA:
605 	case KEY_RSA_CERT_V00:
606 	case KEY_RSA_CERT:
607 	case KEY_RSA1:
608 		if (RSA_blinding_on(k->rsa, NULL) != 1) {
609 			error("process_add_identity: RSA_blinding_on failed");
610 			key_free(k);
611 			goto send;
612 		}
613 		break;
614 	}
615 	comment = buffer_get_string(&e->request, NULL);
616 	if (k == NULL) {
617 		xfree(comment);
618 		goto send;
619 	}
620 	while (buffer_len(&e->request)) {
621 		switch ((type = buffer_get_char(&e->request))) {
622 		case SSH_AGENT_CONSTRAIN_LIFETIME:
623 			death = time(NULL) + buffer_get_int(&e->request);
624 			break;
625 		case SSH_AGENT_CONSTRAIN_CONFIRM:
626 			confirm = 1;
627 			break;
628 		default:
629 			error("process_add_identity: "
630 			    "Unknown constraint type %d", type);
631 			xfree(comment);
632 			key_free(k);
633 			goto send;
634 		}
635 	}
636 	success = 1;
637 	if (lifetime && !death)
638 		death = time(NULL) + lifetime;
639 	if ((id = lookup_identity(k, version)) == NULL) {
640 		id = xcalloc(1, sizeof(Identity));
641 		id->key = k;
642 		TAILQ_INSERT_TAIL(&tab->idlist, id, next);
643 		/* Increment the number of identities. */
644 		tab->nentries++;
645 	} else {
646 		key_free(k);
647 		xfree(id->comment);
648 	}
649 	id->comment = comment;
650 	id->death = death;
651 	id->confirm = confirm;
652 send:
653 	buffer_put_int(&e->output, 1);
654 	buffer_put_char(&e->output,
655 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
656 }
657 
658 /* XXX todo: encrypt sensitive data with passphrase */
659 static void
660 process_lock_agent(SocketEntry *e, int lock)
661 {
662 	int success = 0;
663 	char *passwd;
664 
665 	passwd = buffer_get_string(&e->request, NULL);
666 	if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
667 		locked = 0;
668 		memset(lock_passwd, 0, strlen(lock_passwd));
669 		xfree(lock_passwd);
670 		lock_passwd = NULL;
671 		success = 1;
672 	} else if (!locked && lock) {
673 		locked = 1;
674 		lock_passwd = xstrdup(passwd);
675 		success = 1;
676 	}
677 	memset(passwd, 0, strlen(passwd));
678 	xfree(passwd);
679 
680 	buffer_put_int(&e->output, 1);
681 	buffer_put_char(&e->output,
682 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
683 }
684 
685 static void
686 no_identities(SocketEntry *e, u_int type)
687 {
688 	Buffer msg;
689 
690 	buffer_init(&msg);
691 	buffer_put_char(&msg,
692 	    (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
693 	    SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
694 	buffer_put_int(&msg, 0);
695 	buffer_put_int(&e->output, buffer_len(&msg));
696 	buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
697 	buffer_free(&msg);
698 }
699 
700 #ifdef ENABLE_PKCS11
701 static void
702 process_add_smartcard_key(SocketEntry *e)
703 {
704 	char *provider = NULL, *pin;
705 	int i, type, version, count = 0, success = 0, death = 0, confirm = 0;
706 	Key **keys = NULL, *k;
707 	Identity *id;
708 	Idtab *tab;
709 
710 	provider = buffer_get_string(&e->request, NULL);
711 	pin = buffer_get_string(&e->request, NULL);
712 
713 	while (buffer_len(&e->request)) {
714 		switch ((type = buffer_get_char(&e->request))) {
715 		case SSH_AGENT_CONSTRAIN_LIFETIME:
716 			death = time(NULL) + buffer_get_int(&e->request);
717 			break;
718 		case SSH_AGENT_CONSTRAIN_CONFIRM:
719 			confirm = 1;
720 			break;
721 		default:
722 			error("process_add_smartcard_key: "
723 			    "Unknown constraint type %d", type);
724 			goto send;
725 		}
726 	}
727 	if (lifetime && !death)
728 		death = time(NULL) + lifetime;
729 
730 	count = pkcs11_add_provider(provider, pin, &keys);
731 	for (i = 0; i < count; i++) {
732 		k = keys[i];
733 		version = k->type == KEY_RSA1 ? 1 : 2;
734 		tab = idtab_lookup(version);
735 		if (lookup_identity(k, version) == NULL) {
736 			id = xcalloc(1, sizeof(Identity));
737 			id->key = k;
738 			id->provider = xstrdup(provider);
739 			id->comment = xstrdup(provider); /* XXX */
740 			id->death = death;
741 			id->confirm = confirm;
742 			TAILQ_INSERT_TAIL(&tab->idlist, id, next);
743 			tab->nentries++;
744 			success = 1;
745 		} else {
746 			key_free(k);
747 		}
748 		keys[i] = NULL;
749 	}
750 send:
751 	if (pin)
752 		xfree(pin);
753 	if (provider)
754 		xfree(provider);
755 	if (keys)
756 		xfree(keys);
757 	buffer_put_int(&e->output, 1);
758 	buffer_put_char(&e->output,
759 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
760 }
761 
762 static void
763 process_remove_smartcard_key(SocketEntry *e)
764 {
765 	char *provider = NULL, *pin = NULL;
766 	int version, success = 0;
767 	Identity *id, *nxt;
768 	Idtab *tab;
769 
770 	provider = buffer_get_string(&e->request, NULL);
771 	pin = buffer_get_string(&e->request, NULL);
772 	xfree(pin);
773 
774 	for (version = 1; version < 3; version++) {
775 		tab = idtab_lookup(version);
776 		for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
777 			nxt = TAILQ_NEXT(id, next);
778 			if (!strcmp(provider, id->provider)) {
779 				TAILQ_REMOVE(&tab->idlist, id, next);
780 				free_identity(id);
781 				tab->nentries--;
782 			}
783 		}
784 	}
785 	if (pkcs11_del_provider(provider) == 0)
786 		success = 1;
787 	else
788 		error("process_remove_smartcard_key:"
789 		    " pkcs11_del_provider failed");
790 	xfree(provider);
791 	buffer_put_int(&e->output, 1);
792 	buffer_put_char(&e->output,
793 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
794 }
795 #endif /* ENABLE_PKCS11 */
796 
797 /* dispatch incoming messages */
798 
799 static void
800 process_message(SocketEntry *e)
801 {
802 	u_int msg_len, type;
803 	u_char *cp;
804 
805 	if (buffer_len(&e->input) < 5)
806 		return;		/* Incomplete message. */
807 	cp = buffer_ptr(&e->input);
808 	msg_len = get_u32(cp);
809 	if (msg_len > 256 * 1024) {
810 		close_socket(e);
811 		return;
812 	}
813 	if (buffer_len(&e->input) < msg_len + 4)
814 		return;
815 
816 	/* move the current input to e->request */
817 	buffer_consume(&e->input, 4);
818 	buffer_clear(&e->request);
819 	buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
820 	buffer_consume(&e->input, msg_len);
821 	type = buffer_get_char(&e->request);
822 
823 	/* check wheter agent is locked */
824 	if (locked && type != SSH_AGENTC_UNLOCK) {
825 		buffer_clear(&e->request);
826 		switch (type) {
827 		case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
828 		case SSH2_AGENTC_REQUEST_IDENTITIES:
829 			/* send empty lists */
830 			no_identities(e, type);
831 			break;
832 		default:
833 			/* send a fail message for all other request types */
834 			buffer_put_int(&e->output, 1);
835 			buffer_put_char(&e->output, SSH_AGENT_FAILURE);
836 		}
837 		return;
838 	}
839 
840 	debug("type %d", type);
841 	switch (type) {
842 	case SSH_AGENTC_LOCK:
843 	case SSH_AGENTC_UNLOCK:
844 		process_lock_agent(e, type == SSH_AGENTC_LOCK);
845 		break;
846 	/* ssh1 */
847 	case SSH_AGENTC_RSA_CHALLENGE:
848 		process_authentication_challenge1(e);
849 		break;
850 	case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
851 		process_request_identities(e, 1);
852 		break;
853 	case SSH_AGENTC_ADD_RSA_IDENTITY:
854 	case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
855 		process_add_identity(e, 1);
856 		break;
857 	case SSH_AGENTC_REMOVE_RSA_IDENTITY:
858 		process_remove_identity(e, 1);
859 		break;
860 	case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
861 		process_remove_all_identities(e, 1);
862 		break;
863 	/* ssh2 */
864 	case SSH2_AGENTC_SIGN_REQUEST:
865 		process_sign_request2(e);
866 		break;
867 	case SSH2_AGENTC_REQUEST_IDENTITIES:
868 		process_request_identities(e, 2);
869 		break;
870 	case SSH2_AGENTC_ADD_IDENTITY:
871 	case SSH2_AGENTC_ADD_ID_CONSTRAINED:
872 		process_add_identity(e, 2);
873 		break;
874 	case SSH2_AGENTC_REMOVE_IDENTITY:
875 		process_remove_identity(e, 2);
876 		break;
877 	case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
878 		process_remove_all_identities(e, 2);
879 		break;
880 #ifdef ENABLE_PKCS11
881 	case SSH_AGENTC_ADD_SMARTCARD_KEY:
882 	case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
883 		process_add_smartcard_key(e);
884 		break;
885 	case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
886 		process_remove_smartcard_key(e);
887 		break;
888 #endif /* ENABLE_PKCS11 */
889 	default:
890 		/* Unknown message.  Respond with failure. */
891 		error("Unknown message %d", type);
892 		buffer_clear(&e->request);
893 		buffer_put_int(&e->output, 1);
894 		buffer_put_char(&e->output, SSH_AGENT_FAILURE);
895 		break;
896 	}
897 }
898 
899 static void
900 new_socket(sock_type type, int fd)
901 {
902 	u_int i, old_alloc, new_alloc;
903 
904 	set_nonblock(fd);
905 
906 	if (fd > max_fd)
907 		max_fd = fd;
908 
909 	for (i = 0; i < sockets_alloc; i++)
910 		if (sockets[i].type == AUTH_UNUSED) {
911 			sockets[i].fd = fd;
912 			buffer_init(&sockets[i].input);
913 			buffer_init(&sockets[i].output);
914 			buffer_init(&sockets[i].request);
915 			sockets[i].type = type;
916 			return;
917 		}
918 	old_alloc = sockets_alloc;
919 	new_alloc = sockets_alloc + 10;
920 	sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
921 	for (i = old_alloc; i < new_alloc; i++)
922 		sockets[i].type = AUTH_UNUSED;
923 	sockets_alloc = new_alloc;
924 	sockets[old_alloc].fd = fd;
925 	buffer_init(&sockets[old_alloc].input);
926 	buffer_init(&sockets[old_alloc].output);
927 	buffer_init(&sockets[old_alloc].request);
928 	sockets[old_alloc].type = type;
929 }
930 
931 static int
932 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
933     struct timeval **tvpp)
934 {
935 	u_int i, sz, deadline;
936 	int n = 0;
937 	static struct timeval tv;
938 
939 	for (i = 0; i < sockets_alloc; i++) {
940 		switch (sockets[i].type) {
941 		case AUTH_SOCKET:
942 		case AUTH_CONNECTION:
943 			n = MAX(n, sockets[i].fd);
944 			break;
945 		case AUTH_UNUSED:
946 			break;
947 		default:
948 			fatal("Unknown socket type %d", sockets[i].type);
949 			break;
950 		}
951 	}
952 
953 	sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
954 	if (*fdrp == NULL || sz > *nallocp) {
955 		if (*fdrp)
956 			xfree(*fdrp);
957 		if (*fdwp)
958 			xfree(*fdwp);
959 		*fdrp = xmalloc(sz);
960 		*fdwp = xmalloc(sz);
961 		*nallocp = sz;
962 	}
963 	if (n < *fdl)
964 		debug("XXX shrink: %d < %d", n, *fdl);
965 	*fdl = n;
966 	memset(*fdrp, 0, sz);
967 	memset(*fdwp, 0, sz);
968 
969 	for (i = 0; i < sockets_alloc; i++) {
970 		switch (sockets[i].type) {
971 		case AUTH_SOCKET:
972 		case AUTH_CONNECTION:
973 			FD_SET(sockets[i].fd, *fdrp);
974 			if (buffer_len(&sockets[i].output) > 0)
975 				FD_SET(sockets[i].fd, *fdwp);
976 			break;
977 		default:
978 			break;
979 		}
980 	}
981 	deadline = reaper();
982 	if (parent_alive_interval != 0)
983 		deadline = (deadline == 0) ? parent_alive_interval :
984 		    MIN(deadline, parent_alive_interval);
985 	if (deadline == 0) {
986 		*tvpp = NULL;
987 	} else {
988 		tv.tv_sec = deadline;
989 		tv.tv_usec = 0;
990 		*tvpp = &tv;
991 	}
992 	return (1);
993 }
994 
995 static void
996 after_select(fd_set *readset, fd_set *writeset)
997 {
998 	struct sockaddr_un sunaddr;
999 	socklen_t slen;
1000 	char buf[1024];
1001 	int len, sock;
1002 	u_int i, orig_alloc;
1003 	uid_t euid;
1004 	gid_t egid;
1005 
1006 	for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
1007 		switch (sockets[i].type) {
1008 		case AUTH_UNUSED:
1009 			break;
1010 		case AUTH_SOCKET:
1011 			if (FD_ISSET(sockets[i].fd, readset)) {
1012 				slen = sizeof(sunaddr);
1013 				sock = accept(sockets[i].fd,
1014 				    (struct sockaddr *)&sunaddr, &slen);
1015 				if (sock < 0) {
1016 					error("accept from AUTH_SOCKET: %s",
1017 					    strerror(errno));
1018 					break;
1019 				}
1020 				if (getpeereid(sock, &euid, &egid) < 0) {
1021 					error("getpeereid %d failed: %s",
1022 					    sock, strerror(errno));
1023 					close(sock);
1024 					break;
1025 				}
1026 				if ((euid != 0) && (getuid() != euid)) {
1027 					error("uid mismatch: "
1028 					    "peer euid %u != uid %u",
1029 					    (u_int) euid, (u_int) getuid());
1030 					close(sock);
1031 					break;
1032 				}
1033 				new_socket(AUTH_CONNECTION, sock);
1034 			}
1035 			break;
1036 		case AUTH_CONNECTION:
1037 			if (buffer_len(&sockets[i].output) > 0 &&
1038 			    FD_ISSET(sockets[i].fd, writeset)) {
1039 				len = write(sockets[i].fd,
1040 				    buffer_ptr(&sockets[i].output),
1041 				    buffer_len(&sockets[i].output));
1042 				if (len == -1 && (errno == EAGAIN ||
1043 				    errno == EWOULDBLOCK ||
1044 				    errno == EINTR))
1045 					continue;
1046 				if (len <= 0) {
1047 					close_socket(&sockets[i]);
1048 					break;
1049 				}
1050 				buffer_consume(&sockets[i].output, len);
1051 			}
1052 			if (FD_ISSET(sockets[i].fd, readset)) {
1053 				len = read(sockets[i].fd, buf, sizeof(buf));
1054 				if (len == -1 && (errno == EAGAIN ||
1055 				    errno == EWOULDBLOCK ||
1056 				    errno == EINTR))
1057 					continue;
1058 				if (len <= 0) {
1059 					close_socket(&sockets[i]);
1060 					break;
1061 				}
1062 				buffer_append(&sockets[i].input, buf, len);
1063 				process_message(&sockets[i]);
1064 			}
1065 			break;
1066 		default:
1067 			fatal("Unknown type %d", sockets[i].type);
1068 		}
1069 }
1070 
1071 static void
1072 cleanup_socket(void)
1073 {
1074 	if (socket_name[0])
1075 		unlink(socket_name);
1076 	if (socket_dir[0])
1077 		rmdir(socket_dir);
1078 }
1079 
1080 void
1081 cleanup_exit(int i)
1082 {
1083 	cleanup_socket();
1084 	_exit(i);
1085 }
1086 
1087 /*ARGSUSED*/
1088 static void
1089 cleanup_handler(int sig)
1090 {
1091 	cleanup_socket();
1092 #ifdef ENABLE_PKCS11
1093 	pkcs11_terminate();
1094 #endif
1095 	_exit(2);
1096 }
1097 
1098 static void
1099 check_parent_exists(void)
1100 {
1101 	if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1102 		/* printf("Parent has died - Authentication agent exiting.\n"); */
1103 		cleanup_socket();
1104 		_exit(2);
1105 	}
1106 }
1107 
1108 static void
1109 usage(void)
1110 {
1111 	fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1112 	    __progname);
1113 	fprintf(stderr, "Options:\n");
1114 	fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
1115 	fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
1116 	fprintf(stderr, "  -k          Kill the current agent.\n");
1117 	fprintf(stderr, "  -d          Debug mode.\n");
1118 	fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
1119 	fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
1120 	exit(1);
1121 }
1122 
1123 int
1124 main(int ac, char **av)
1125 {
1126 	int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1127 	int sock, fd, ch, result, saved_errno;
1128 	u_int nalloc;
1129 	char *shell, *format, *pidstr, *agentsocket = NULL;
1130 	fd_set *readsetp = NULL, *writesetp = NULL;
1131 	struct sockaddr_un sunaddr;
1132 #ifdef HAVE_SETRLIMIT
1133 	struct rlimit rlim;
1134 #endif
1135 	int prev_mask;
1136 	extern int optind;
1137 	extern char *optarg;
1138 	pid_t pid;
1139 	char pidstrbuf[1 + 3 * sizeof pid];
1140 	struct timeval *tvp = NULL;
1141 	size_t len;
1142 
1143 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1144 	sanitise_stdfd();
1145 
1146 	/* drop */
1147 	setegid(getgid());
1148 	setgid(getgid());
1149 	setuid(geteuid());
1150 
1151 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1152 	/* Disable ptrace on Linux without sgid bit */
1153 	prctl(PR_SET_DUMPABLE, 0);
1154 #endif
1155 
1156 	OpenSSL_add_all_algorithms();
1157 
1158 	__progname = ssh_get_progname(av[0]);
1159 	init_rng();
1160 	seed_rng();
1161 
1162 	while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1163 		switch (ch) {
1164 		case 'c':
1165 			if (s_flag)
1166 				usage();
1167 			c_flag++;
1168 			break;
1169 		case 'k':
1170 			k_flag++;
1171 			break;
1172 		case 's':
1173 			if (c_flag)
1174 				usage();
1175 			s_flag++;
1176 			break;
1177 		case 'd':
1178 			if (d_flag)
1179 				usage();
1180 			d_flag++;
1181 			break;
1182 		case 'a':
1183 			agentsocket = optarg;
1184 			break;
1185 		case 't':
1186 			if ((lifetime = convtime(optarg)) == -1) {
1187 				fprintf(stderr, "Invalid lifetime\n");
1188 				usage();
1189 			}
1190 			break;
1191 		default:
1192 			usage();
1193 		}
1194 	}
1195 	ac -= optind;
1196 	av += optind;
1197 
1198 	if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1199 		usage();
1200 
1201 	if (ac == 0 && !c_flag && !s_flag) {
1202 		shell = getenv("SHELL");
1203 		if (shell != NULL && (len = strlen(shell)) > 2 &&
1204 		    strncmp(shell + len - 3, "csh", 3) == 0)
1205 			c_flag = 1;
1206 	}
1207 	if (k_flag) {
1208 		const char *errstr = NULL;
1209 
1210 		pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1211 		if (pidstr == NULL) {
1212 			fprintf(stderr, "%s not set, cannot kill agent\n",
1213 			    SSH_AGENTPID_ENV_NAME);
1214 			exit(1);
1215 		}
1216 		pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1217 		if (errstr) {
1218 			fprintf(stderr,
1219 			    "%s=\"%s\", which is not a good PID: %s\n",
1220 			    SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1221 			exit(1);
1222 		}
1223 		if (kill(pid, SIGTERM) == -1) {
1224 			perror("kill");
1225 			exit(1);
1226 		}
1227 		format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1228 		printf(format, SSH_AUTHSOCKET_ENV_NAME);
1229 		printf(format, SSH_AGENTPID_ENV_NAME);
1230 		printf("echo Agent pid %ld killed;\n", (long)pid);
1231 		exit(0);
1232 	}
1233 	parent_pid = getpid();
1234 
1235 	if (agentsocket == NULL) {
1236 		/* Create private directory for agent socket */
1237 		mktemp_proto(socket_dir, sizeof(socket_dir));
1238 		if (mkdtemp(socket_dir) == NULL) {
1239 			perror("mkdtemp: private socket dir");
1240 			exit(1);
1241 		}
1242 		snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1243 		    (long)parent_pid);
1244 	} else {
1245 		/* Try to use specified agent socket */
1246 		socket_dir[0] = '\0';
1247 		strlcpy(socket_name, agentsocket, sizeof socket_name);
1248 	}
1249 
1250 	/*
1251 	 * Create socket early so it will exist before command gets run from
1252 	 * the parent.
1253 	 */
1254 	sock = socket(AF_UNIX, SOCK_STREAM, 0);
1255 	if (sock < 0) {
1256 		perror("socket");
1257 		*socket_name = '\0'; /* Don't unlink any existing file */
1258 		cleanup_exit(1);
1259 	}
1260 	memset(&sunaddr, 0, sizeof(sunaddr));
1261 	sunaddr.sun_family = AF_UNIX;
1262 	strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1263 	prev_mask = umask(0177);
1264 	if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1265 		perror("bind");
1266 		*socket_name = '\0'; /* Don't unlink any existing file */
1267 		umask(prev_mask);
1268 		cleanup_exit(1);
1269 	}
1270 	umask(prev_mask);
1271 	if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1272 		perror("listen");
1273 		cleanup_exit(1);
1274 	}
1275 
1276 	/*
1277 	 * Fork, and have the parent execute the command, if any, or present
1278 	 * the socket data.  The child continues as the authentication agent.
1279 	 */
1280 	if (d_flag) {
1281 		log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1282 		format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1283 		printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1284 		    SSH_AUTHSOCKET_ENV_NAME);
1285 		printf("echo Agent pid %ld;\n", (long)parent_pid);
1286 		goto skip;
1287 	}
1288 	pid = fork();
1289 	if (pid == -1) {
1290 		perror("fork");
1291 		cleanup_exit(1);
1292 	}
1293 	if (pid != 0) {		/* Parent - execute the given command. */
1294 		close(sock);
1295 		snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1296 		if (ac == 0) {
1297 			format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1298 			printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1299 			    SSH_AUTHSOCKET_ENV_NAME);
1300 			printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1301 			    SSH_AGENTPID_ENV_NAME);
1302 			printf("echo Agent pid %ld;\n", (long)pid);
1303 			exit(0);
1304 		}
1305 		if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1306 		    setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1307 			perror("setenv");
1308 			exit(1);
1309 		}
1310 		execvp(av[0], av);
1311 		perror(av[0]);
1312 		exit(1);
1313 	}
1314 	/* child */
1315 	log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1316 
1317 	if (setsid() == -1) {
1318 		error("setsid: %s", strerror(errno));
1319 		cleanup_exit(1);
1320 	}
1321 
1322 	(void)chdir("/");
1323 	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1324 		/* XXX might close listen socket */
1325 		(void)dup2(fd, STDIN_FILENO);
1326 		(void)dup2(fd, STDOUT_FILENO);
1327 		(void)dup2(fd, STDERR_FILENO);
1328 		if (fd > 2)
1329 			close(fd);
1330 	}
1331 
1332 #ifdef HAVE_SETRLIMIT
1333 	/* deny core dumps, since memory contains unencrypted private keys */
1334 	rlim.rlim_cur = rlim.rlim_max = 0;
1335 	if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1336 		error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1337 		cleanup_exit(1);
1338 	}
1339 #endif
1340 
1341 skip:
1342 
1343 #ifdef ENABLE_PKCS11
1344 	pkcs11_init(0);
1345 #endif
1346 	new_socket(AUTH_SOCKET, sock);
1347 	if (ac > 0)
1348 		parent_alive_interval = 10;
1349 	idtab_init();
1350 	if (!d_flag)
1351 		signal(SIGINT, SIG_IGN);
1352 	signal(SIGPIPE, SIG_IGN);
1353 	signal(SIGHUP, cleanup_handler);
1354 	signal(SIGTERM, cleanup_handler);
1355 	nalloc = 0;
1356 
1357 	while (1) {
1358 		prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1359 		result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1360 		saved_errno = errno;
1361 		if (parent_alive_interval != 0)
1362 			check_parent_exists();
1363 		(void) reaper();	/* remove expired keys */
1364 		if (result < 0) {
1365 			if (saved_errno == EINTR)
1366 				continue;
1367 			fatal("select: %s", strerror(saved_errno));
1368 		} else if (result > 0)
1369 			after_select(readsetp, writesetp);
1370 	}
1371 	/* NOTREACHED */
1372 }
1373