1 /* $OpenBSD: ssh-agent.c,v 1.218 2017/03/15 03:52:30 deraadt 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
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #include <sys/resource.h>
42 #include <sys/stat.h>
43 #include <sys/socket.h>
44 #ifdef HAVE_SYS_TIME_H
45 # include <sys/time.h>
46 #endif
47 #ifdef HAVE_SYS_UN_H
48 # include <sys/un.h>
49 #endif
50 #include "openbsd-compat/sys-queue.h"
51
52 #ifdef WITH_OPENSSL
53 #include <openssl/evp.h>
54 #include "openbsd-compat/openssl-compat.h"
55 #endif
56
57 #include <errno.h>
58 #include <fcntl.h>
59 #include <limits.h>
60 #ifdef HAVE_PATHS_H
61 # include <paths.h>
62 #endif
63 #include <signal.h>
64 #include <stdarg.h>
65 #include <stdio.h>
66 #include <stdlib.h>
67 #include <time.h>
68 #include <string.h>
69 #include <unistd.h>
70 #ifdef HAVE_UTIL_H
71 # include <util.h>
72 #endif
73
74 #include "xmalloc.h"
75 #include "ssh.h"
76 #include "rsa.h"
77 #include "sshbuf.h"
78 #include "sshkey.h"
79 #include "authfd.h"
80 #include "compat.h"
81 #include "log.h"
82 #include "misc.h"
83 #include "digest.h"
84 #include "ssherr.h"
85 #include "match.h"
86
87 #ifdef ENABLE_PKCS11
88 #include "ssh-pkcs11.h"
89 #endif
90
91 #ifndef DEFAULT_PKCS11_WHITELIST
92 # define DEFAULT_PKCS11_WHITELIST "/usr/lib*/*,/usr/local/lib*/*"
93 #endif
94
95 typedef enum {
96 AUTH_UNUSED,
97 AUTH_SOCKET,
98 AUTH_CONNECTION
99 } sock_type;
100
101 typedef struct {
102 int fd;
103 sock_type type;
104 struct sshbuf *input;
105 struct sshbuf *output;
106 struct sshbuf *request;
107 } SocketEntry;
108
109 u_int sockets_alloc = 0;
110 SocketEntry *sockets = NULL;
111
112 typedef struct identity {
113 TAILQ_ENTRY(identity) next;
114 struct sshkey *key;
115 char *comment;
116 char *provider;
117 time_t death;
118 u_int confirm;
119 } Identity;
120
121 typedef struct {
122 int nentries;
123 TAILQ_HEAD(idqueue, identity) idlist;
124 } Idtab;
125
126 /* private key table, one per protocol version */
127 Idtab idtable[3];
128
129 int max_fd = 0;
130
131 /* pid of shell == parent of agent */
132 pid_t parent_pid = -1;
133 time_t parent_alive_interval = 0;
134
135 /* pid of process for which cleanup_socket is applicable */
136 pid_t cleanup_pid = 0;
137
138 /* pathname and directory for AUTH_SOCKET */
139 char socket_name[PATH_MAX];
140 char socket_dir[PATH_MAX];
141
142 /* PKCS#11 path whitelist */
143 static char *pkcs11_whitelist;
144
145 /* locking */
146 #define LOCK_SIZE 32
147 #define LOCK_SALT_SIZE 16
148 #define LOCK_ROUNDS 1
149 int locked = 0;
150 u_char lock_pwhash[LOCK_SIZE];
151 u_char lock_salt[LOCK_SALT_SIZE];
152
153 extern char *__progname;
154
155 /* Default lifetime in seconds (0 == forever) */
156 static long lifetime = 0;
157
158 static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
159
160 static void
close_socket(SocketEntry * e)161 close_socket(SocketEntry *e)
162 {
163 close(e->fd);
164 e->fd = -1;
165 e->type = AUTH_UNUSED;
166 sshbuf_free(e->input);
167 sshbuf_free(e->output);
168 sshbuf_free(e->request);
169 }
170
171 static void
idtab_init(void)172 idtab_init(void)
173 {
174 int i;
175
176 for (i = 0; i <=2; i++) {
177 TAILQ_INIT(&idtable[i].idlist);
178 idtable[i].nentries = 0;
179 }
180 }
181
182 /* return private key table for requested protocol version */
183 static Idtab *
idtab_lookup(int version)184 idtab_lookup(int version)
185 {
186 if (version < 1 || version > 2)
187 fatal("internal error, bad protocol version %d", version);
188 return &idtable[version];
189 }
190
191 static void
free_identity(Identity * id)192 free_identity(Identity *id)
193 {
194 sshkey_free(id->key);
195 free(id->provider);
196 free(id->comment);
197 free(id);
198 }
199
200 /* return matching private key for given public key */
201 static Identity *
lookup_identity(struct sshkey * key,int version)202 lookup_identity(struct sshkey *key, int version)
203 {
204 Identity *id;
205
206 Idtab *tab = idtab_lookup(version);
207 TAILQ_FOREACH(id, &tab->idlist, next) {
208 if (sshkey_equal(key, id->key))
209 return (id);
210 }
211 return (NULL);
212 }
213
214 /* Check confirmation of keysign request */
215 static int
confirm_key(Identity * id)216 confirm_key(Identity *id)
217 {
218 char *p;
219 int ret = -1;
220
221 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
222 if (p != NULL &&
223 ask_permission("Allow use of key %s?\nKey fingerprint %s.",
224 id->comment, p))
225 ret = 0;
226 free(p);
227
228 return (ret);
229 }
230
231 static void
send_status(SocketEntry * e,int success)232 send_status(SocketEntry *e, int success)
233 {
234 int r;
235
236 if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
237 (r = sshbuf_put_u8(e->output, success ?
238 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
239 fatal("%s: buffer error: %s", __func__, ssh_err(r));
240 }
241
242 /* send list of supported public keys to 'client' */
243 static void
process_request_identities(SocketEntry * e,int version)244 process_request_identities(SocketEntry *e, int version)
245 {
246 Idtab *tab = idtab_lookup(version);
247 Identity *id;
248 struct sshbuf *msg;
249 int r;
250
251 if ((msg = sshbuf_new()) == NULL)
252 fatal("%s: sshbuf_new failed", __func__);
253 if ((r = sshbuf_put_u8(msg, (version == 1) ?
254 SSH_AGENT_RSA_IDENTITIES_ANSWER :
255 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
256 (r = sshbuf_put_u32(msg, tab->nentries)) != 0)
257 fatal("%s: buffer error: %s", __func__, ssh_err(r));
258 TAILQ_FOREACH(id, &tab->idlist, next) {
259 if (id->key->type == KEY_RSA1) {
260 #ifdef WITH_SSH1
261 if ((r = sshbuf_put_u32(msg,
262 BN_num_bits(id->key->rsa->n))) != 0 ||
263 (r = sshbuf_put_bignum1(msg,
264 id->key->rsa->e)) != 0 ||
265 (r = sshbuf_put_bignum1(msg,
266 id->key->rsa->n)) != 0)
267 fatal("%s: buffer error: %s",
268 __func__, ssh_err(r));
269 #endif
270 } else {
271 u_char *blob;
272 size_t blen;
273
274 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) {
275 error("%s: sshkey_to_blob: %s", __func__,
276 ssh_err(r));
277 continue;
278 }
279 if ((r = sshbuf_put_string(msg, blob, blen)) != 0)
280 fatal("%s: buffer error: %s",
281 __func__, ssh_err(r));
282 free(blob);
283 }
284 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0)
285 fatal("%s: buffer error: %s", __func__, ssh_err(r));
286 }
287 if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
288 fatal("%s: buffer error: %s", __func__, ssh_err(r));
289 sshbuf_free(msg);
290 }
291
292 #ifdef WITH_SSH1
293 /* ssh1 only */
294 static void
process_authentication_challenge1(SocketEntry * e)295 process_authentication_challenge1(SocketEntry *e)
296 {
297 u_char buf[32], mdbuf[16], session_id[16];
298 u_int response_type;
299 BIGNUM *challenge;
300 Identity *id;
301 int r, len;
302 struct sshbuf *msg;
303 struct ssh_digest_ctx *md;
304 struct sshkey *key;
305
306 if ((msg = sshbuf_new()) == NULL)
307 fatal("%s: sshbuf_new failed", __func__);
308 if ((key = sshkey_new(KEY_RSA1)) == NULL)
309 fatal("%s: sshkey_new failed", __func__);
310 if ((challenge = BN_new()) == NULL)
311 fatal("%s: BN_new failed", __func__);
312
313 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */
314 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 ||
315 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 ||
316 (r = sshbuf_get_bignum1(e->request, challenge)))
317 fatal("%s: buffer error: %s", __func__, ssh_err(r));
318
319 /* Only protocol 1.1 is supported */
320 if (sshbuf_len(e->request) == 0)
321 goto failure;
322 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 ||
323 (r = sshbuf_get_u32(e->request, &response_type)) != 0)
324 fatal("%s: buffer error: %s", __func__, ssh_err(r));
325 if (response_type != 1)
326 goto failure;
327
328 id = lookup_identity(key, 1);
329 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
330 struct sshkey *private = id->key;
331 /* Decrypt the challenge using the private key. */
332 if ((r = rsa_private_decrypt(challenge, challenge,
333 private->rsa) != 0)) {
334 fatal("%s: rsa_public_encrypt: %s", __func__,
335 ssh_err(r));
336 goto failure; /* XXX ? */
337 }
338
339 /* The response is MD5 of decrypted challenge plus session id */
340 len = BN_num_bytes(challenge);
341 if (len <= 0 || len > 32) {
342 logit("%s: bad challenge length %d", __func__, len);
343 goto failure;
344 }
345 memset(buf, 0, 32);
346 BN_bn2bin(challenge, buf + 32 - len);
347 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL ||
348 ssh_digest_update(md, buf, 32) < 0 ||
349 ssh_digest_update(md, session_id, 16) < 0 ||
350 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0)
351 fatal("%s: md5 failed", __func__);
352 ssh_digest_free(md);
353
354 /* Send the response. */
355 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 ||
356 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0)
357 fatal("%s: buffer error: %s", __func__, ssh_err(r));
358 goto send;
359 }
360
361 failure:
362 /* Unknown identity or protocol error. Send failure. */
363 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
364 fatal("%s: buffer error: %s", __func__, ssh_err(r));
365 send:
366 if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
367 fatal("%s: buffer error: %s", __func__, ssh_err(r));
368 sshkey_free(key);
369 BN_clear_free(challenge);
370 sshbuf_free(msg);
371 }
372 #endif
373
374 static char *
agent_decode_alg(struct sshkey * key,u_int flags)375 agent_decode_alg(struct sshkey *key, u_int flags)
376 {
377 if (key->type == KEY_RSA) {
378 if (flags & SSH_AGENT_RSA_SHA2_256)
379 return "rsa-sha2-256";
380 else if (flags & SSH_AGENT_RSA_SHA2_512)
381 return "rsa-sha2-512";
382 }
383 return NULL;
384 }
385
386 /* ssh2 only */
387 static void
process_sign_request2(SocketEntry * e)388 process_sign_request2(SocketEntry *e)
389 {
390 u_char *blob, *data, *signature = NULL;
391 size_t blen, dlen, slen = 0;
392 u_int compat = 0, flags;
393 int r, ok = -1;
394 struct sshbuf *msg;
395 struct sshkey *key;
396 struct identity *id;
397
398 if ((msg = sshbuf_new()) == NULL)
399 fatal("%s: sshbuf_new failed", __func__);
400 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 ||
401 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 ||
402 (r = sshbuf_get_u32(e->request, &flags)) != 0)
403 fatal("%s: buffer error: %s", __func__, ssh_err(r));
404 if (flags & SSH_AGENT_OLD_SIGNATURE)
405 compat = SSH_BUG_SIGBLOB;
406 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) {
407 error("%s: cannot parse key blob: %s", __func__, ssh_err(r));
408 goto send;
409 }
410 if ((id = lookup_identity(key, 2)) == NULL) {
411 verbose("%s: %s key not found", __func__, sshkey_type(key));
412 goto send;
413 }
414 if (id->confirm && confirm_key(id) != 0) {
415 verbose("%s: user refused key", __func__);
416 goto send;
417 }
418 if ((r = sshkey_sign(id->key, &signature, &slen,
419 data, dlen, agent_decode_alg(key, flags), compat)) != 0) {
420 error("%s: sshkey_sign: %s", __func__, ssh_err(r));
421 goto send;
422 }
423 /* Success */
424 ok = 0;
425 send:
426 sshkey_free(key);
427 if (ok == 0) {
428 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
429 (r = sshbuf_put_string(msg, signature, slen)) != 0)
430 fatal("%s: buffer error: %s", __func__, ssh_err(r));
431 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
432 fatal("%s: buffer error: %s", __func__, ssh_err(r));
433
434 if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
435 fatal("%s: buffer error: %s", __func__, ssh_err(r));
436
437 sshbuf_free(msg);
438 free(data);
439 free(blob);
440 free(signature);
441 }
442
443 /* shared */
444 static void
process_remove_identity(SocketEntry * e,int version)445 process_remove_identity(SocketEntry *e, int version)
446 {
447 size_t blen;
448 int r, success = 0;
449 struct sshkey *key = NULL;
450 u_char *blob;
451 #ifdef WITH_SSH1
452 u_int bits;
453 #endif /* WITH_SSH1 */
454
455 switch (version) {
456 #ifdef WITH_SSH1
457 case 1:
458 if ((key = sshkey_new(KEY_RSA1)) == NULL) {
459 error("%s: sshkey_new failed", __func__);
460 return;
461 }
462 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 ||
463 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 ||
464 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0)
465 fatal("%s: buffer error: %s", __func__, ssh_err(r));
466
467 if (bits != sshkey_size(key))
468 logit("Warning: identity keysize mismatch: "
469 "actual %u, announced %u",
470 sshkey_size(key), bits);
471 break;
472 #endif /* WITH_SSH1 */
473 case 2:
474 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0)
475 fatal("%s: buffer error: %s", __func__, ssh_err(r));
476 if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
477 error("%s: sshkey_from_blob failed: %s",
478 __func__, ssh_err(r));
479 free(blob);
480 break;
481 }
482 if (key != NULL) {
483 Identity *id = lookup_identity(key, version);
484 if (id != NULL) {
485 /*
486 * We have this key. Free the old key. Since we
487 * don't want to leave empty slots in the middle of
488 * the array, we actually free the key there and move
489 * all the entries between the empty slot and the end
490 * of the array.
491 */
492 Idtab *tab = idtab_lookup(version);
493 if (tab->nentries < 1)
494 fatal("process_remove_identity: "
495 "internal error: tab->nentries %d",
496 tab->nentries);
497 TAILQ_REMOVE(&tab->idlist, id, next);
498 free_identity(id);
499 tab->nentries--;
500 success = 1;
501 }
502 sshkey_free(key);
503 }
504 send_status(e, success);
505 }
506
507 static void
process_remove_all_identities(SocketEntry * e,int version)508 process_remove_all_identities(SocketEntry *e, int version)
509 {
510 Idtab *tab = idtab_lookup(version);
511 Identity *id;
512
513 /* Loop over all identities and clear the keys. */
514 for (id = TAILQ_FIRST(&tab->idlist); id;
515 id = TAILQ_FIRST(&tab->idlist)) {
516 TAILQ_REMOVE(&tab->idlist, id, next);
517 free_identity(id);
518 }
519
520 /* Mark that there are no identities. */
521 tab->nentries = 0;
522
523 /* Send success. */
524 send_status(e, 1);
525 }
526
527 /* removes expired keys and returns number of seconds until the next expiry */
528 static time_t
reaper(void)529 reaper(void)
530 {
531 time_t deadline = 0, now = monotime();
532 Identity *id, *nxt;
533 int version;
534 Idtab *tab;
535
536 for (version = 1; version < 3; version++) {
537 tab = idtab_lookup(version);
538 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
539 nxt = TAILQ_NEXT(id, next);
540 if (id->death == 0)
541 continue;
542 if (now >= id->death) {
543 debug("expiring key '%s'", id->comment);
544 TAILQ_REMOVE(&tab->idlist, id, next);
545 free_identity(id);
546 tab->nentries--;
547 } else
548 deadline = (deadline == 0) ? id->death :
549 MINIMUM(deadline, id->death);
550 }
551 }
552 if (deadline == 0 || deadline <= now)
553 return 0;
554 else
555 return (deadline - now);
556 }
557
558 /*
559 * XXX this and the corresponding serialisation function probably belongs
560 * in key.c
561 */
562 #ifdef WITH_SSH1
563 static int
agent_decode_rsa1(struct sshbuf * m,struct sshkey ** kp)564 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp)
565 {
566 struct sshkey *k = NULL;
567 int r = SSH_ERR_INTERNAL_ERROR;
568
569 *kp = NULL;
570 if ((k = sshkey_new_private(KEY_RSA1)) == NULL)
571 return SSH_ERR_ALLOC_FAIL;
572
573 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */
574 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 ||
575 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 ||
576 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 ||
577 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 ||
578 /* SSH1 and SSL have p and q swapped */
579 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */
580 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */
581 goto out;
582
583 /* Generate additional parameters */
584 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0)
585 goto out;
586 /* enable blinding */
587 if (RSA_blinding_on(k->rsa, NULL) != 1) {
588 r = SSH_ERR_LIBCRYPTO_ERROR;
589 goto out;
590 }
591
592 r = 0; /* success */
593 out:
594 if (r == 0)
595 *kp = k;
596 else
597 sshkey_free(k);
598 return r;
599 }
600 #endif /* WITH_SSH1 */
601
602 static void
process_add_identity(SocketEntry * e,int version)603 process_add_identity(SocketEntry *e, int version)
604 {
605 Idtab *tab = idtab_lookup(version);
606 Identity *id;
607 int success = 0, confirm = 0;
608 u_int seconds;
609 char *comment = NULL;
610 time_t death = 0;
611 struct sshkey *k = NULL;
612 u_char ctype;
613 int r = SSH_ERR_INTERNAL_ERROR;
614
615 switch (version) {
616 #ifdef WITH_SSH1
617 case 1:
618 r = agent_decode_rsa1(e->request, &k);
619 break;
620 #endif /* WITH_SSH1 */
621 case 2:
622 r = sshkey_private_deserialize(e->request, &k);
623 break;
624 }
625 if (r != 0 || k == NULL ||
626 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
627 error("%s: decode private key: %s", __func__, ssh_err(r));
628 goto err;
629 }
630
631 while (sshbuf_len(e->request)) {
632 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) {
633 error("%s: buffer error: %s", __func__, ssh_err(r));
634 goto err;
635 }
636 switch (ctype) {
637 case SSH_AGENT_CONSTRAIN_LIFETIME:
638 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
639 error("%s: bad lifetime constraint: %s",
640 __func__, ssh_err(r));
641 goto err;
642 }
643 death = monotime() + seconds;
644 break;
645 case SSH_AGENT_CONSTRAIN_CONFIRM:
646 confirm = 1;
647 break;
648 default:
649 error("%s: Unknown constraint %d", __func__, ctype);
650 err:
651 sshbuf_reset(e->request);
652 free(comment);
653 sshkey_free(k);
654 goto send;
655 }
656 }
657
658 success = 1;
659 if (lifetime && !death)
660 death = monotime() + lifetime;
661 if ((id = lookup_identity(k, version)) == NULL) {
662 id = xcalloc(1, sizeof(Identity));
663 id->key = k;
664 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
665 /* Increment the number of identities. */
666 tab->nentries++;
667 } else {
668 sshkey_free(k);
669 free(id->comment);
670 }
671 id->comment = comment;
672 id->death = death;
673 id->confirm = confirm;
674 send:
675 send_status(e, success);
676 }
677
678 /* XXX todo: encrypt sensitive data with passphrase */
679 static void
process_lock_agent(SocketEntry * e,int lock)680 process_lock_agent(SocketEntry *e, int lock)
681 {
682 int r, success = 0, delay;
683 char *passwd;
684 u_char passwdhash[LOCK_SIZE];
685 static u_int fail_count = 0;
686 size_t pwlen;
687
688 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
689 fatal("%s: buffer error: %s", __func__, ssh_err(r));
690 if (pwlen == 0) {
691 debug("empty password not supported");
692 } else if (locked && !lock) {
693 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
694 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
695 fatal("bcrypt_pbkdf");
696 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
697 debug("agent unlocked");
698 locked = 0;
699 fail_count = 0;
700 explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
701 success = 1;
702 } else {
703 /* delay in 0.1s increments up to 10s */
704 if (fail_count < 100)
705 fail_count++;
706 delay = 100000 * fail_count;
707 debug("unlock failed, delaying %0.1lf seconds",
708 (double)delay/1000000);
709 usleep(delay);
710 }
711 explicit_bzero(passwdhash, sizeof(passwdhash));
712 } else if (!locked && lock) {
713 debug("agent locked");
714 locked = 1;
715 arc4random_buf(lock_salt, sizeof(lock_salt));
716 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
717 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
718 fatal("bcrypt_pbkdf");
719 success = 1;
720 }
721 explicit_bzero(passwd, pwlen);
722 free(passwd);
723 send_status(e, success);
724 }
725
726 static void
no_identities(SocketEntry * e,u_int type)727 no_identities(SocketEntry *e, u_int type)
728 {
729 struct sshbuf *msg;
730 int r;
731
732 if ((msg = sshbuf_new()) == NULL)
733 fatal("%s: sshbuf_new failed", __func__);
734 if ((r = sshbuf_put_u8(msg,
735 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
736 SSH_AGENT_RSA_IDENTITIES_ANSWER :
737 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
738 (r = sshbuf_put_u32(msg, 0)) != 0 ||
739 (r = sshbuf_put_stringb(e->output, msg)) != 0)
740 fatal("%s: buffer error: %s", __func__, ssh_err(r));
741 sshbuf_free(msg);
742 }
743
744 #ifdef ENABLE_PKCS11
745 static void
process_add_smartcard_key(SocketEntry * e)746 process_add_smartcard_key(SocketEntry *e)
747 {
748 char *provider = NULL, *pin, canonical_provider[PATH_MAX];
749 int r, i, version, count = 0, success = 0, confirm = 0;
750 u_int seconds;
751 time_t death = 0;
752 u_char type;
753 struct sshkey **keys = NULL, *k;
754 Identity *id;
755 Idtab *tab;
756
757 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
758 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0)
759 fatal("%s: buffer error: %s", __func__, ssh_err(r));
760
761 while (sshbuf_len(e->request)) {
762 if ((r = sshbuf_get_u8(e->request, &type)) != 0)
763 fatal("%s: buffer error: %s", __func__, ssh_err(r));
764 switch (type) {
765 case SSH_AGENT_CONSTRAIN_LIFETIME:
766 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0)
767 fatal("%s: buffer error: %s",
768 __func__, ssh_err(r));
769 death = monotime() + seconds;
770 break;
771 case SSH_AGENT_CONSTRAIN_CONFIRM:
772 confirm = 1;
773 break;
774 default:
775 error("process_add_smartcard_key: "
776 "Unknown constraint type %d", type);
777 goto send;
778 }
779 }
780 if (realpath(provider, canonical_provider) == NULL) {
781 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
782 provider, strerror(errno));
783 goto send;
784 }
785 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) {
786 verbose("refusing PKCS#11 add of \"%.100s\": "
787 "provider not whitelisted", canonical_provider);
788 goto send;
789 }
790 debug("%s: add %.100s", __func__, canonical_provider);
791 if (lifetime && !death)
792 death = monotime() + lifetime;
793
794 count = pkcs11_add_provider(canonical_provider, pin, &keys);
795 for (i = 0; i < count; i++) {
796 k = keys[i];
797 version = k->type == KEY_RSA1 ? 1 : 2;
798 tab = idtab_lookup(version);
799 if (lookup_identity(k, version) == NULL) {
800 id = xcalloc(1, sizeof(Identity));
801 id->key = k;
802 id->provider = xstrdup(canonical_provider);
803 id->comment = xstrdup(canonical_provider); /* XXX */
804 id->death = death;
805 id->confirm = confirm;
806 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
807 tab->nentries++;
808 success = 1;
809 } else {
810 sshkey_free(k);
811 }
812 keys[i] = NULL;
813 }
814 send:
815 free(pin);
816 free(provider);
817 free(keys);
818 send_status(e, success);
819 }
820
821 static void
process_remove_smartcard_key(SocketEntry * e)822 process_remove_smartcard_key(SocketEntry *e)
823 {
824 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
825 int r, version, success = 0;
826 Identity *id, *nxt;
827 Idtab *tab;
828
829 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
830 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0)
831 fatal("%s: buffer error: %s", __func__, ssh_err(r));
832 free(pin);
833
834 if (realpath(provider, canonical_provider) == NULL) {
835 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
836 provider, strerror(errno));
837 goto send;
838 }
839
840 debug("%s: remove %.100s", __func__, canonical_provider);
841 for (version = 1; version < 3; version++) {
842 tab = idtab_lookup(version);
843 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
844 nxt = TAILQ_NEXT(id, next);
845 /* Skip file--based keys */
846 if (id->provider == NULL)
847 continue;
848 if (!strcmp(canonical_provider, id->provider)) {
849 TAILQ_REMOVE(&tab->idlist, id, next);
850 free_identity(id);
851 tab->nentries--;
852 }
853 }
854 }
855 if (pkcs11_del_provider(canonical_provider) == 0)
856 success = 1;
857 else
858 error("process_remove_smartcard_key:"
859 " pkcs11_del_provider failed");
860 send:
861 free(provider);
862 send_status(e, success);
863 }
864 #endif /* ENABLE_PKCS11 */
865
866 /* dispatch incoming messages */
867
868 static void
process_message(SocketEntry * e)869 process_message(SocketEntry *e)
870 {
871 u_int msg_len;
872 u_char type;
873 const u_char *cp;
874 int r;
875
876 if (sshbuf_len(e->input) < 5)
877 return; /* Incomplete message. */
878 cp = sshbuf_ptr(e->input);
879 msg_len = PEEK_U32(cp);
880 if (msg_len > 256 * 1024) {
881 close_socket(e);
882 return;
883 }
884 if (sshbuf_len(e->input) < msg_len + 4)
885 return;
886
887 /* move the current input to e->request */
888 sshbuf_reset(e->request);
889 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
890 (r = sshbuf_get_u8(e->request, &type)) != 0)
891 fatal("%s: buffer error: %s", __func__, ssh_err(r));
892
893 /* check wheter agent is locked */
894 if (locked && type != SSH_AGENTC_UNLOCK) {
895 sshbuf_reset(e->request);
896 switch (type) {
897 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
898 case SSH2_AGENTC_REQUEST_IDENTITIES:
899 /* send empty lists */
900 no_identities(e, type);
901 break;
902 default:
903 /* send a fail message for all other request types */
904 send_status(e, 0);
905 }
906 return;
907 }
908
909 debug("type %d", type);
910 switch (type) {
911 case SSH_AGENTC_LOCK:
912 case SSH_AGENTC_UNLOCK:
913 process_lock_agent(e, type == SSH_AGENTC_LOCK);
914 break;
915 #ifdef WITH_SSH1
916 /* ssh1 */
917 case SSH_AGENTC_RSA_CHALLENGE:
918 process_authentication_challenge1(e);
919 break;
920 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
921 process_request_identities(e, 1);
922 break;
923 case SSH_AGENTC_ADD_RSA_IDENTITY:
924 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
925 process_add_identity(e, 1);
926 break;
927 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
928 process_remove_identity(e, 1);
929 break;
930 #endif
931 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
932 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */
933 break;
934 /* ssh2 */
935 case SSH2_AGENTC_SIGN_REQUEST:
936 process_sign_request2(e);
937 break;
938 case SSH2_AGENTC_REQUEST_IDENTITIES:
939 process_request_identities(e, 2);
940 break;
941 case SSH2_AGENTC_ADD_IDENTITY:
942 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
943 process_add_identity(e, 2);
944 break;
945 case SSH2_AGENTC_REMOVE_IDENTITY:
946 process_remove_identity(e, 2);
947 break;
948 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
949 process_remove_all_identities(e, 2);
950 break;
951 #ifdef ENABLE_PKCS11
952 case SSH_AGENTC_ADD_SMARTCARD_KEY:
953 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
954 process_add_smartcard_key(e);
955 break;
956 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
957 process_remove_smartcard_key(e);
958 break;
959 #endif /* ENABLE_PKCS11 */
960 default:
961 /* Unknown message. Respond with failure. */
962 error("Unknown message %d", type);
963 sshbuf_reset(e->request);
964 send_status(e, 0);
965 break;
966 }
967 }
968
969 static void
new_socket(sock_type type,int fd)970 new_socket(sock_type type, int fd)
971 {
972 u_int i, old_alloc, new_alloc;
973
974 set_nonblock(fd);
975
976 if (fd > max_fd)
977 max_fd = fd;
978
979 for (i = 0; i < sockets_alloc; i++)
980 if (sockets[i].type == AUTH_UNUSED) {
981 sockets[i].fd = fd;
982 if ((sockets[i].input = sshbuf_new()) == NULL)
983 fatal("%s: sshbuf_new failed", __func__);
984 if ((sockets[i].output = sshbuf_new()) == NULL)
985 fatal("%s: sshbuf_new failed", __func__);
986 if ((sockets[i].request = sshbuf_new()) == NULL)
987 fatal("%s: sshbuf_new failed", __func__);
988 sockets[i].type = type;
989 return;
990 }
991 old_alloc = sockets_alloc;
992 new_alloc = sockets_alloc + 10;
993 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0]));
994 for (i = old_alloc; i < new_alloc; i++)
995 sockets[i].type = AUTH_UNUSED;
996 sockets_alloc = new_alloc;
997 sockets[old_alloc].fd = fd;
998 if ((sockets[old_alloc].input = sshbuf_new()) == NULL)
999 fatal("%s: sshbuf_new failed", __func__);
1000 if ((sockets[old_alloc].output = sshbuf_new()) == NULL)
1001 fatal("%s: sshbuf_new failed", __func__);
1002 if ((sockets[old_alloc].request = sshbuf_new()) == NULL)
1003 fatal("%s: sshbuf_new failed", __func__);
1004 sockets[old_alloc].type = type;
1005 }
1006
1007 static int
prepare_select(fd_set ** fdrp,fd_set ** fdwp,int * fdl,u_int * nallocp,struct timeval ** tvpp)1008 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
1009 struct timeval **tvpp)
1010 {
1011 u_int i, sz;
1012 int n = 0;
1013 static struct timeval tv;
1014 time_t deadline;
1015
1016 for (i = 0; i < sockets_alloc; i++) {
1017 switch (sockets[i].type) {
1018 case AUTH_SOCKET:
1019 case AUTH_CONNECTION:
1020 n = MAXIMUM(n, sockets[i].fd);
1021 break;
1022 case AUTH_UNUSED:
1023 break;
1024 default:
1025 fatal("Unknown socket type %d", sockets[i].type);
1026 break;
1027 }
1028 }
1029
1030 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1031 if (*fdrp == NULL || sz > *nallocp) {
1032 free(*fdrp);
1033 free(*fdwp);
1034 *fdrp = xmalloc(sz);
1035 *fdwp = xmalloc(sz);
1036 *nallocp = sz;
1037 }
1038 if (n < *fdl)
1039 debug("XXX shrink: %d < %d", n, *fdl);
1040 *fdl = n;
1041 memset(*fdrp, 0, sz);
1042 memset(*fdwp, 0, sz);
1043
1044 for (i = 0; i < sockets_alloc; i++) {
1045 switch (sockets[i].type) {
1046 case AUTH_SOCKET:
1047 case AUTH_CONNECTION:
1048 FD_SET(sockets[i].fd, *fdrp);
1049 if (sshbuf_len(sockets[i].output) > 0)
1050 FD_SET(sockets[i].fd, *fdwp);
1051 break;
1052 default:
1053 break;
1054 }
1055 }
1056 deadline = reaper();
1057 if (parent_alive_interval != 0)
1058 deadline = (deadline == 0) ? parent_alive_interval :
1059 MINIMUM(deadline, parent_alive_interval);
1060 if (deadline == 0) {
1061 *tvpp = NULL;
1062 } else {
1063 tv.tv_sec = deadline;
1064 tv.tv_usec = 0;
1065 *tvpp = &tv;
1066 }
1067 return (1);
1068 }
1069
1070 static void
after_select(fd_set * readset,fd_set * writeset)1071 after_select(fd_set *readset, fd_set *writeset)
1072 {
1073 struct sockaddr_un sunaddr;
1074 socklen_t slen;
1075 char buf[1024];
1076 int len, sock, r;
1077 u_int i, orig_alloc;
1078 uid_t euid;
1079 gid_t egid;
1080
1081 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
1082 switch (sockets[i].type) {
1083 case AUTH_UNUSED:
1084 break;
1085 case AUTH_SOCKET:
1086 if (FD_ISSET(sockets[i].fd, readset)) {
1087 slen = sizeof(sunaddr);
1088 sock = accept(sockets[i].fd,
1089 (struct sockaddr *)&sunaddr, &slen);
1090 if (sock < 0) {
1091 error("accept from AUTH_SOCKET: %s",
1092 strerror(errno));
1093 break;
1094 }
1095 if (getpeereid(sock, &euid, &egid) < 0) {
1096 error("getpeereid %d failed: %s",
1097 sock, strerror(errno));
1098 close(sock);
1099 break;
1100 }
1101 if ((euid != 0) && (getuid() != euid)) {
1102 error("uid mismatch: "
1103 "peer euid %u != uid %u",
1104 (u_int) euid, (u_int) getuid());
1105 close(sock);
1106 break;
1107 }
1108 new_socket(AUTH_CONNECTION, sock);
1109 }
1110 break;
1111 case AUTH_CONNECTION:
1112 if (sshbuf_len(sockets[i].output) > 0 &&
1113 FD_ISSET(sockets[i].fd, writeset)) {
1114 len = write(sockets[i].fd,
1115 sshbuf_ptr(sockets[i].output),
1116 sshbuf_len(sockets[i].output));
1117 if (len == -1 && (errno == EAGAIN ||
1118 errno == EWOULDBLOCK ||
1119 errno == EINTR))
1120 continue;
1121 if (len <= 0) {
1122 close_socket(&sockets[i]);
1123 break;
1124 }
1125 if ((r = sshbuf_consume(sockets[i].output,
1126 len)) != 0)
1127 fatal("%s: buffer error: %s",
1128 __func__, ssh_err(r));
1129 }
1130 if (FD_ISSET(sockets[i].fd, readset)) {
1131 len = read(sockets[i].fd, buf, sizeof(buf));
1132 if (len == -1 && (errno == EAGAIN ||
1133 errno == EWOULDBLOCK ||
1134 errno == EINTR))
1135 continue;
1136 if (len <= 0) {
1137 close_socket(&sockets[i]);
1138 break;
1139 }
1140 if ((r = sshbuf_put(sockets[i].input,
1141 buf, len)) != 0)
1142 fatal("%s: buffer error: %s",
1143 __func__, ssh_err(r));
1144 explicit_bzero(buf, sizeof(buf));
1145 process_message(&sockets[i]);
1146 }
1147 break;
1148 default:
1149 fatal("Unknown type %d", sockets[i].type);
1150 }
1151 }
1152
1153 static void
cleanup_socket(void)1154 cleanup_socket(void)
1155 {
1156 if (cleanup_pid != 0 && getpid() != cleanup_pid)
1157 return;
1158 debug("%s: cleanup", __func__);
1159 if (socket_name[0])
1160 unlink(socket_name);
1161 if (socket_dir[0])
1162 rmdir(socket_dir);
1163 }
1164
1165 void
cleanup_exit(int i)1166 cleanup_exit(int i)
1167 {
1168 cleanup_socket();
1169 _exit(i);
1170 }
1171
1172 /*ARGSUSED*/
1173 static void
cleanup_handler(int sig)1174 cleanup_handler(int sig)
1175 {
1176 cleanup_socket();
1177 #ifdef ENABLE_PKCS11
1178 pkcs11_terminate();
1179 #endif
1180 _exit(2);
1181 }
1182
1183 static void
check_parent_exists(void)1184 check_parent_exists(void)
1185 {
1186 /*
1187 * If our parent has exited then getppid() will return (pid_t)1,
1188 * so testing for that should be safe.
1189 */
1190 if (parent_pid != -1 && getppid() != parent_pid) {
1191 /* printf("Parent has died - Authentication agent exiting.\n"); */
1192 cleanup_socket();
1193 _exit(2);
1194 }
1195 }
1196
1197 static void
usage(void)1198 usage(void)
1199 {
1200 fprintf(stderr,
1201 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n"
1202 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n"
1203 " ssh-agent [-c | -s] -k\n");
1204 exit(1);
1205 }
1206
1207 int
main(int ac,char ** av)1208 main(int ac, char **av)
1209 {
1210 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
1211 int sock, fd, ch, result, saved_errno;
1212 u_int nalloc;
1213 char *shell, *format, *pidstr, *agentsocket = NULL;
1214 fd_set *readsetp = NULL, *writesetp = NULL;
1215 #ifdef HAVE_SETRLIMIT
1216 struct rlimit rlim;
1217 #endif
1218 extern int optind;
1219 extern char *optarg;
1220 pid_t pid;
1221 char pidstrbuf[1 + 3 * sizeof pid];
1222 struct timeval *tvp = NULL;
1223 size_t len;
1224 mode_t prev_mask;
1225
1226 ssh_malloc_init(); /* must be called before any mallocs */
1227 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1228 sanitise_stdfd();
1229
1230 /* drop */
1231 setegid(getgid());
1232 setgid(getgid());
1233
1234 platform_disable_tracing(0); /* strict=no */
1235
1236 #ifdef WITH_OPENSSL
1237 OpenSSL_add_all_algorithms();
1238 #endif
1239
1240 __progname = ssh_get_progname(av[0]);
1241 seed_rng();
1242
1243 while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) {
1244 switch (ch) {
1245 case 'E':
1246 fingerprint_hash = ssh_digest_alg_by_name(optarg);
1247 if (fingerprint_hash == -1)
1248 fatal("Invalid hash algorithm \"%s\"", optarg);
1249 break;
1250 case 'c':
1251 if (s_flag)
1252 usage();
1253 c_flag++;
1254 break;
1255 case 'k':
1256 k_flag++;
1257 break;
1258 case 'P':
1259 if (pkcs11_whitelist != NULL)
1260 fatal("-P option already specified");
1261 pkcs11_whitelist = xstrdup(optarg);
1262 break;
1263 case 's':
1264 if (c_flag)
1265 usage();
1266 s_flag++;
1267 break;
1268 case 'd':
1269 if (d_flag || D_flag)
1270 usage();
1271 d_flag++;
1272 break;
1273 case 'D':
1274 if (d_flag || D_flag)
1275 usage();
1276 D_flag++;
1277 break;
1278 case 'a':
1279 agentsocket = optarg;
1280 break;
1281 case 't':
1282 if ((lifetime = convtime(optarg)) == -1) {
1283 fprintf(stderr, "Invalid lifetime\n");
1284 usage();
1285 }
1286 break;
1287 default:
1288 usage();
1289 }
1290 }
1291 ac -= optind;
1292 av += optind;
1293
1294 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
1295 usage();
1296
1297 if (pkcs11_whitelist == NULL)
1298 pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST);
1299
1300 if (ac == 0 && !c_flag && !s_flag) {
1301 shell = getenv("SHELL");
1302 if (shell != NULL && (len = strlen(shell)) > 2 &&
1303 strncmp(shell + len - 3, "csh", 3) == 0)
1304 c_flag = 1;
1305 }
1306 if (k_flag) {
1307 const char *errstr = NULL;
1308
1309 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1310 if (pidstr == NULL) {
1311 fprintf(stderr, "%s not set, cannot kill agent\n",
1312 SSH_AGENTPID_ENV_NAME);
1313 exit(1);
1314 }
1315 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1316 if (errstr) {
1317 fprintf(stderr,
1318 "%s=\"%s\", which is not a good PID: %s\n",
1319 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1320 exit(1);
1321 }
1322 if (kill(pid, SIGTERM) == -1) {
1323 perror("kill");
1324 exit(1);
1325 }
1326 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1327 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1328 printf(format, SSH_AGENTPID_ENV_NAME);
1329 printf("echo Agent pid %ld killed;\n", (long)pid);
1330 exit(0);
1331 }
1332 parent_pid = getpid();
1333
1334 if (agentsocket == NULL) {
1335 /* Create private directory for agent socket */
1336 mktemp_proto(socket_dir, sizeof(socket_dir));
1337 if (mkdtemp(socket_dir) == NULL) {
1338 perror("mkdtemp: private socket dir");
1339 exit(1);
1340 }
1341 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1342 (long)parent_pid);
1343 } else {
1344 /* Try to use specified agent socket */
1345 socket_dir[0] = '\0';
1346 strlcpy(socket_name, agentsocket, sizeof socket_name);
1347 }
1348
1349 /*
1350 * Create socket early so it will exist before command gets run from
1351 * the parent.
1352 */
1353 prev_mask = umask(0177);
1354 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
1355 if (sock < 0) {
1356 /* XXX - unix_listener() calls error() not perror() */
1357 *socket_name = '\0'; /* Don't unlink any existing file */
1358 cleanup_exit(1);
1359 }
1360 umask(prev_mask);
1361
1362 /*
1363 * Fork, and have the parent execute the command, if any, or present
1364 * the socket data. The child continues as the authentication agent.
1365 */
1366 if (D_flag || d_flag) {
1367 log_init(__progname,
1368 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
1369 SYSLOG_FACILITY_AUTH, 1);
1370 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1371 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1372 SSH_AUTHSOCKET_ENV_NAME);
1373 printf("echo Agent pid %ld;\n", (long)parent_pid);
1374 fflush(stdout);
1375 goto skip;
1376 }
1377 pid = fork();
1378 if (pid == -1) {
1379 perror("fork");
1380 cleanup_exit(1);
1381 }
1382 if (pid != 0) { /* Parent - execute the given command. */
1383 close(sock);
1384 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1385 if (ac == 0) {
1386 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1387 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1388 SSH_AUTHSOCKET_ENV_NAME);
1389 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1390 SSH_AGENTPID_ENV_NAME);
1391 printf("echo Agent pid %ld;\n", (long)pid);
1392 exit(0);
1393 }
1394 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1395 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1396 perror("setenv");
1397 exit(1);
1398 }
1399 execvp(av[0], av);
1400 perror(av[0]);
1401 exit(1);
1402 }
1403 /* child */
1404 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1405
1406 if (setsid() == -1) {
1407 error("setsid: %s", strerror(errno));
1408 cleanup_exit(1);
1409 }
1410
1411 (void)chdir("/");
1412 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1413 /* XXX might close listen socket */
1414 (void)dup2(fd, STDIN_FILENO);
1415 (void)dup2(fd, STDOUT_FILENO);
1416 (void)dup2(fd, STDERR_FILENO);
1417 if (fd > 2)
1418 close(fd);
1419 }
1420
1421 #ifdef HAVE_SETRLIMIT
1422 /* deny core dumps, since memory contains unencrypted private keys */
1423 rlim.rlim_cur = rlim.rlim_max = 0;
1424 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1425 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1426 cleanup_exit(1);
1427 }
1428 #endif
1429
1430 skip:
1431
1432 cleanup_pid = getpid();
1433
1434 #ifdef ENABLE_PKCS11
1435 pkcs11_init(0);
1436 #endif
1437 new_socket(AUTH_SOCKET, sock);
1438 if (ac > 0)
1439 parent_alive_interval = 10;
1440 idtab_init();
1441 signal(SIGPIPE, SIG_IGN);
1442 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
1443 signal(SIGHUP, cleanup_handler);
1444 signal(SIGTERM, cleanup_handler);
1445 nalloc = 0;
1446
1447 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
1448 fatal("%s: pledge: %s", __progname, strerror(errno));
1449 platform_pledge_agent();
1450
1451 while (1) {
1452 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1453 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1454 saved_errno = errno;
1455 if (parent_alive_interval != 0)
1456 check_parent_exists();
1457 (void) reaper(); /* remove expired keys */
1458 if (result < 0) {
1459 if (saved_errno == EINTR)
1460 continue;
1461 fatal("select: %s", strerror(saved_errno));
1462 } else if (result > 0)
1463 after_select(readsetp, writesetp);
1464 }
1465 /* NOTREACHED */
1466 }
1467