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- (djm) Release 5.7p1
[openssh-git.git] / ssh-agent.c
blobafba413d7827366fc15f2f83e3afe1bfb90bacd2
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
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 #include <openssl/evp.h>
53 #include <openssl/md5.h>
54 #include "openbsd-compat/openssl-compat.h"
55
56 #include <errno.h>
57 #include <fcntl.h>
58 #ifdef HAVE_PATHS_H
59 # include <paths.h>
60 #endif
61 #include <signal.h>
62 #include <stdarg.h>
63 #include <stdio.h>
64 #include <stdlib.h>
65 #include <time.h>
66 #include <string.h>
67 #include <unistd.h>
68
69 #include "xmalloc.h"
70 #include "ssh.h"
71 #include "rsa.h"
72 #include "buffer.h"
73 #include "key.h"
74 #include "authfd.h"
75 #include "compat.h"
76 #include "log.h"
77 #include "misc.h"
78
79 #ifdef ENABLE_PKCS11
80 #include "ssh-pkcs11.h"
81 #endif
82
83 #if defined(HAVE_SYS_PRCTL_H)
84 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
85 #endif
86
87 typedef enum {
88 AUTH_UNUSED,
89 AUTH_SOCKET,
90 AUTH_CONNECTION
91 } sock_type;
92
93 typedef struct {
94 int fd;
95 sock_type type;
96 Buffer input;
97 Buffer output;
98 Buffer request;
99 } SocketEntry;
100
101 u_int sockets_alloc = 0;
102 SocketEntry *sockets = NULL;
103
104 typedef struct identity {
105 TAILQ_ENTRY(identity) next;
106 Key *key;
107 char *comment;
108 char *provider;
109 u_int death;
110 u_int confirm;
111 } Identity;
112
113 typedef struct {
114 int nentries;
115 TAILQ_HEAD(idqueue, identity) idlist;
116 } Idtab;
117
118 /* private key table, one per protocol version */
119 Idtab idtable[3];
120
121 int max_fd = 0;
122
123 /* pid of shell == parent of agent */
124 pid_t parent_pid = -1;
125 u_int parent_alive_interval = 0;
126
127 /* pathname and directory for AUTH_SOCKET */
128 char socket_name[MAXPATHLEN];
129 char socket_dir[MAXPATHLEN];
130
131 /* locking */
132 int locked = 0;
133 char *lock_passwd = NULL;
134
135 extern char *__progname;
136
137 /* Default lifetime (0 == forever) */
138 static int lifetime = 0;
139
140 static void
141 close_socket(SocketEntry *e)
142 {
143 close(e->fd);
144 e->fd = -1;
145 e->type = AUTH_UNUSED;
146 buffer_free(&e->input);
147 buffer_free(&e->output);
148 buffer_free(&e->request);
149 }
150
151 static void
152 idtab_init(void)
153 {
154 int i;
155
156 for (i = 0; i <=2; i++) {
157 TAILQ_INIT(&idtable[i].idlist);
158 idtable[i].nentries = 0;
159 }
160 }
161
162 /* return private key table for requested protocol version */
163 static Idtab *
164 idtab_lookup(int version)
165 {
166 if (version < 1 || version > 2)
167 fatal("internal error, bad protocol version %d", version);
168 return &idtable[version];
169 }
170
171 static void
172 free_identity(Identity *id)
173 {
174 key_free(id->key);
175 if (id->provider != NULL)
176 xfree(id->provider);
177 xfree(id->comment);
178 xfree(id);
179 }
180
181 /* return matching private key for given public key */
182 static Identity *
183 lookup_identity(Key *key, int version)
184 {
185 Identity *id;
186
187 Idtab *tab = idtab_lookup(version);
188 TAILQ_FOREACH(id, &tab->idlist, next) {
189 if (key_equal(key, id->key))
190 return (id);
191 }
192 return (NULL);
193 }
194
195 /* Check confirmation of keysign request */
196 static int
197 confirm_key(Identity *id)
198 {
199 char *p;
200 int ret = -1;
201
202 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
203 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
204 id->comment, p))
205 ret = 0;
206 xfree(p);
207
208 return (ret);
209 }
210
211 /* send list of supported public keys to 'client' */
212 static void
213 process_request_identities(SocketEntry *e, int version)
214 {
215 Idtab *tab = idtab_lookup(version);
216 Identity *id;
217 Buffer msg;
218
219 buffer_init(&msg);
220 buffer_put_char(&msg, (version == 1) ?
221 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
222 buffer_put_int(&msg, tab->nentries);
223 TAILQ_FOREACH(id, &tab->idlist, next) {
224 if (id->key->type == KEY_RSA1) {
225 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
226 buffer_put_bignum(&msg, id->key->rsa->e);
227 buffer_put_bignum(&msg, id->key->rsa->n);
228 } else {
229 u_char *blob;
230 u_int blen;
231 key_to_blob(id->key, &blob, &blen);
232 buffer_put_string(&msg, blob, blen);
233 xfree(blob);
234 }
235 buffer_put_cstring(&msg, id->comment);
236 }
237 buffer_put_int(&e->output, buffer_len(&msg));
238 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
239 buffer_free(&msg);
240 }
241
242 /* ssh1 only */
243 static void
244 process_authentication_challenge1(SocketEntry *e)
245 {
246 u_char buf[32], mdbuf[16], session_id[16];
247 u_int response_type;
248 BIGNUM *challenge;
249 Identity *id;
250 int i, len;
251 Buffer msg;
252 MD5_CTX md;
253 Key *key;
254
255 buffer_init(&msg);
256 key = key_new(KEY_RSA1);
257 if ((challenge = BN_new()) == NULL)
258 fatal("process_authentication_challenge1: BN_new failed");
259
260 (void) buffer_get_int(&e->request); /* ignored */
261 buffer_get_bignum(&e->request, key->rsa->e);
262 buffer_get_bignum(&e->request, key->rsa->n);
263 buffer_get_bignum(&e->request, challenge);
264
265 /* Only protocol 1.1 is supported */
266 if (buffer_len(&e->request) == 0)
267 goto failure;
268 buffer_get(&e->request, session_id, 16);
269 response_type = buffer_get_int(&e->request);
270 if (response_type != 1)
271 goto failure;
272
273 id = lookup_identity(key, 1);
274 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
275 Key *private = id->key;
276 /* Decrypt the challenge using the private key. */
277 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
278 goto failure;
279
280 /* The response is MD5 of decrypted challenge plus session id. */
281 len = BN_num_bytes(challenge);
282 if (len <= 0 || len > 32) {
283 logit("process_authentication_challenge: bad challenge length %d", len);
284 goto failure;
285 }
286 memset(buf, 0, 32);
287 BN_bn2bin(challenge, buf + 32 - len);
288 MD5_Init(&md);
289 MD5_Update(&md, buf, 32);
290 MD5_Update(&md, session_id, 16);
291 MD5_Final(mdbuf, &md);
292
293 /* Send the response. */
294 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
295 for (i = 0; i < 16; i++)
296 buffer_put_char(&msg, mdbuf[i]);
297 goto send;
298 }
299
300 failure:
301 /* Unknown identity or protocol error. Send failure. */
302 buffer_put_char(&msg, SSH_AGENT_FAILURE);
303 send:
304 buffer_put_int(&e->output, buffer_len(&msg));
305 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
306 key_free(key);
307 BN_clear_free(challenge);
308 buffer_free(&msg);
309 }
310
311 /* ssh2 only */
312 static void
313 process_sign_request2(SocketEntry *e)
314 {
315 u_char *blob, *data, *signature = NULL;
316 u_int blen, dlen, slen = 0;
317 extern int datafellows;
318 int odatafellows;
319 int ok = -1, flags;
320 Buffer msg;
321 Key *key;
322
323 datafellows = 0;
324
325 blob = buffer_get_string(&e->request, &blen);
326 data = buffer_get_string(&e->request, &dlen);
327
328 flags = buffer_get_int(&e->request);
329 odatafellows = datafellows;
330 if (flags & SSH_AGENT_OLD_SIGNATURE)
331 datafellows = SSH_BUG_SIGBLOB;
332
333 key = key_from_blob(blob, blen);
334 if (key != NULL) {
335 Identity *id = lookup_identity(key, 2);
336 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
337 ok = key_sign(id->key, &signature, &slen, data, dlen);
338 key_free(key);
339 }
340 buffer_init(&msg);
341 if (ok == 0) {
342 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
343 buffer_put_string(&msg, signature, slen);
344 } else {
345 buffer_put_char(&msg, SSH_AGENT_FAILURE);
346 }
347 buffer_put_int(&e->output, buffer_len(&msg));
348 buffer_append(&e->output, buffer_ptr(&msg),
349 buffer_len(&msg));
350 buffer_free(&msg);
351 xfree(data);
352 xfree(blob);
353 if (signature != NULL)
354 xfree(signature);
355 datafellows = odatafellows;
356 }
357
358 /* shared */
359 static void
360 process_remove_identity(SocketEntry *e, int version)
361 {
362 u_int blen, bits;
363 int success = 0;
364 Key *key = NULL;
365 u_char *blob;
366
367 switch (version) {
368 case 1:
369 key = key_new(KEY_RSA1);
370 bits = buffer_get_int(&e->request);
371 buffer_get_bignum(&e->request, key->rsa->e);
372 buffer_get_bignum(&e->request, key->rsa->n);
373
374 if (bits != key_size(key))
375 logit("Warning: identity keysize mismatch: actual %u, announced %u",
376 key_size(key), bits);
377 break;
378 case 2:
379 blob = buffer_get_string(&e->request, &blen);
380 key = key_from_blob(blob, blen);
381 xfree(blob);
382 break;
383 }
384 if (key != NULL) {
385 Identity *id = lookup_identity(key, version);
386 if (id != NULL) {
387 /*
388 * We have this key. Free the old key. Since we
389 * don't want to leave empty slots in the middle of
390 * the array, we actually free the key there and move
391 * all the entries between the empty slot and the end
392 * of the array.
393 */
394 Idtab *tab = idtab_lookup(version);
395 if (tab->nentries < 1)
396 fatal("process_remove_identity: "
397 "internal error: tab->nentries %d",
398 tab->nentries);
399 TAILQ_REMOVE(&tab->idlist, id, next);
400 free_identity(id);
401 tab->nentries--;
402 success = 1;
403 }
404 key_free(key);
405 }
406 buffer_put_int(&e->output, 1);
407 buffer_put_char(&e->output,
408 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
409 }
410
411 static void
412 process_remove_all_identities(SocketEntry *e, int version)
413 {
414 Idtab *tab = idtab_lookup(version);
415 Identity *id;
416
417 /* Loop over all identities and clear the keys. */
418 for (id = TAILQ_FIRST(&tab->idlist); id;
419 id = TAILQ_FIRST(&tab->idlist)) {
420 TAILQ_REMOVE(&tab->idlist, id, next);
421 free_identity(id);
422 }
423
424 /* Mark that there are no identities. */
425 tab->nentries = 0;
426
427 /* Send success. */
428 buffer_put_int(&e->output, 1);
429 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
430 }
431
432 /* removes expired keys and returns number of seconds until the next expiry */
433 static u_int
434 reaper(void)
435 {
436 u_int deadline = 0, now = time(NULL);
437 Identity *id, *nxt;
438 int version;
439 Idtab *tab;
440
441 for (version = 1; version < 3; version++) {
442 tab = idtab_lookup(version);
443 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
444 nxt = TAILQ_NEXT(id, next);
445 if (id->death == 0)
446 continue;
447 if (now >= id->death) {
448 debug("expiring key '%s'", id->comment);
449 TAILQ_REMOVE(&tab->idlist, id, next);
450 free_identity(id);
451 tab->nentries--;
452 } else
453 deadline = (deadline == 0) ? id->death :
454 MIN(deadline, id->death);
455 }
456 }
457 if (deadline == 0 || deadline <= now)
458 return 0;
459 else
460 return (deadline - now);
461 }
462
463 static void
464 process_add_identity(SocketEntry *e, int version)
465 {
466 Idtab *tab = idtab_lookup(version);
467 Identity *id;
468 int type, success = 0, death = 0, confirm = 0;
469 char *type_name, *comment;
470 Key *k = NULL;
471 #ifdef OPENSSL_HAS_ECC
472 BIGNUM *exponent;
473 EC_POINT *q;
474 char *curve;
475 #endif
476 u_char *cert;
477 u_int len;
478
479 switch (version) {
480 case 1:
481 k = key_new_private(KEY_RSA1);
482 (void) buffer_get_int(&e->request); /* ignored */
483 buffer_get_bignum(&e->request, k->rsa->n);
484 buffer_get_bignum(&e->request, k->rsa->e);
485 buffer_get_bignum(&e->request, k->rsa->d);
486 buffer_get_bignum(&e->request, k->rsa->iqmp);
487
488 /* SSH and SSL have p and q swapped */
489 buffer_get_bignum(&e->request, k->rsa->q); /* p */
490 buffer_get_bignum(&e->request, k->rsa->p); /* q */
491
492 /* Generate additional parameters */
493 rsa_generate_additional_parameters(k->rsa);
494 break;
495 case 2:
496 type_name = buffer_get_string(&e->request, NULL);
497 type = key_type_from_name(type_name);
498 switch (type) {
499 case KEY_DSA:
500 k = key_new_private(type);
501 buffer_get_bignum2(&e->request, k->dsa->p);
502 buffer_get_bignum2(&e->request, k->dsa->q);
503 buffer_get_bignum2(&e->request, k->dsa->g);
504 buffer_get_bignum2(&e->request, k->dsa->pub_key);
505 buffer_get_bignum2(&e->request, k->dsa->priv_key);
506 break;
507 case KEY_DSA_CERT_V00:
508 case KEY_DSA_CERT:
509 cert = buffer_get_string(&e->request, &len);
510 if ((k = key_from_blob(cert, len)) == NULL)
511 fatal("Certificate parse failed");
512 xfree(cert);
513 key_add_private(k);
514 buffer_get_bignum2(&e->request, k->dsa->priv_key);
515 break;
516 #ifdef OPENSSL_HAS_ECC
517 case KEY_ECDSA:
518 k = key_new_private(type);
519 k->ecdsa_nid = key_ecdsa_nid_from_name(type_name);
520 curve = buffer_get_string(&e->request, NULL);
521 if (k->ecdsa_nid != key_curve_name_to_nid(curve))
522 fatal("%s: curve names mismatch", __func__);
523 xfree(curve);
524 k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
525 if (k->ecdsa == NULL)
526 fatal("%s: EC_KEY_new_by_curve_name failed",
527 __func__);
528 q = EC_POINT_new(EC_KEY_get0_group(k->ecdsa));
529 if (q == NULL)
530 fatal("%s: BN_new failed", __func__);
531 if ((exponent = BN_new()) == NULL)
532 fatal("%s: BN_new failed", __func__);
533 buffer_get_ecpoint(&e->request,
534 EC_KEY_get0_group(k->ecdsa), q);
535 buffer_get_bignum2(&e->request, exponent);
536 if (EC_KEY_set_public_key(k->ecdsa, q) != 1)
537 fatal("%s: EC_KEY_set_public_key failed",
538 __func__);
539 if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1)
540 fatal("%s: EC_KEY_set_private_key failed",
541 __func__);
542 if (key_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
543 EC_KEY_get0_public_key(k->ecdsa)) != 0)
544 fatal("%s: bad ECDSA public key", __func__);
545 if (key_ec_validate_private(k->ecdsa) != 0)
546 fatal("%s: bad ECDSA private key", __func__);
547 BN_clear_free(exponent);
548 EC_POINT_free(q);
549 break;
550 case KEY_ECDSA_CERT:
551 cert = buffer_get_string(&e->request, &len);
552 if ((k = key_from_blob(cert, len)) == NULL)
553 fatal("Certificate parse failed");
554 xfree(cert);
555 key_add_private(k);
556 if ((exponent = BN_new()) == NULL)
557 fatal("%s: BN_new failed", __func__);
558 buffer_get_bignum2(&e->request, exponent);
559 if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1)
560 fatal("%s: EC_KEY_set_private_key failed",
561 __func__);
562 if (key_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
563 EC_KEY_get0_public_key(k->ecdsa)) != 0 ||
564 key_ec_validate_private(k->ecdsa) != 0)
565 fatal("%s: bad ECDSA key", __func__);
566 BN_clear_free(exponent);
567 break;
568 #endif /* OPENSSL_HAS_ECC */
569 case KEY_RSA:
570 k = key_new_private(type);
571 buffer_get_bignum2(&e->request, k->rsa->n);
572 buffer_get_bignum2(&e->request, k->rsa->e);
573 buffer_get_bignum2(&e->request, k->rsa->d);
574 buffer_get_bignum2(&e->request, k->rsa->iqmp);
575 buffer_get_bignum2(&e->request, k->rsa->p);
576 buffer_get_bignum2(&e->request, k->rsa->q);
577
578 /* Generate additional parameters */
579 rsa_generate_additional_parameters(k->rsa);
580 break;
581 case KEY_RSA_CERT_V00:
582 case KEY_RSA_CERT:
583 cert = buffer_get_string(&e->request, &len);
584 if ((k = key_from_blob(cert, len)) == NULL)
585 fatal("Certificate parse failed");
586 xfree(cert);
587 key_add_private(k);
588 buffer_get_bignum2(&e->request, k->rsa->d);
589 buffer_get_bignum2(&e->request, k->rsa->iqmp);
590 buffer_get_bignum2(&e->request, k->rsa->p);
591 buffer_get_bignum2(&e->request, k->rsa->q);
592 break;
593 default:
594 xfree(type_name);
595 buffer_clear(&e->request);
596 goto send;
597 }
598 xfree(type_name);
599 break;
600 }
601 /* enable blinding */
602 switch (k->type) {
603 case KEY_RSA:
604 case KEY_RSA_CERT_V00:
605 case KEY_RSA_CERT:
606 case KEY_RSA1:
607 if (RSA_blinding_on(k->rsa, NULL) != 1) {
608 error("process_add_identity: RSA_blinding_on failed");
609 key_free(k);
610 goto send;
611 }
612 break;
613 }
614 comment = buffer_get_string(&e->request, NULL);
615 if (k == NULL) {
616 xfree(comment);
617 goto send;
618 }
619 while (buffer_len(&e->request)) {
620 switch ((type = buffer_get_char(&e->request))) {
621 case SSH_AGENT_CONSTRAIN_LIFETIME:
622 death = time(NULL) + buffer_get_int(&e->request);
623 break;
624 case SSH_AGENT_CONSTRAIN_CONFIRM:
625 confirm = 1;
626 break;
627 default:
628 error("process_add_identity: "
629 "Unknown constraint type %d", type);
630 xfree(comment);
631 key_free(k);
632 goto send;
633 }
634 }
635 success = 1;
636 if (lifetime && !death)
637 death = time(NULL) + lifetime;
638 if ((id = lookup_identity(k, version)) == NULL) {
639 id = xcalloc(1, sizeof(Identity));
640 id->key = k;
641 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
642 /* Increment the number of identities. */
643 tab->nentries++;
644 } else {
645 key_free(k);
646 xfree(id->comment);
647 }
648 id->comment = comment;
649 id->death = death;
650 id->confirm = confirm;
651 send:
652 buffer_put_int(&e->output, 1);
653 buffer_put_char(&e->output,
654 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
655 }
656
657 /* XXX todo: encrypt sensitive data with passphrase */
658 static void
659 process_lock_agent(SocketEntry *e, int lock)
660 {
661 int success = 0;
662 char *passwd;
663
664 passwd = buffer_get_string(&e->request, NULL);
665 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
666 locked = 0;
667 memset(lock_passwd, 0, strlen(lock_passwd));
668 xfree(lock_passwd);
669 lock_passwd = NULL;
670 success = 1;
671 } else if (!locked && lock) {
672 locked = 1;
673 lock_passwd = xstrdup(passwd);
674 success = 1;
675 }
676 memset(passwd, 0, strlen(passwd));
677 xfree(passwd);
678
679 buffer_put_int(&e->output, 1);
680 buffer_put_char(&e->output,
681 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
682 }
683
684 static void
685 no_identities(SocketEntry *e, u_int type)
686 {
687 Buffer msg;
688
689 buffer_init(&msg);
690 buffer_put_char(&msg,
691 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
692 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
693 buffer_put_int(&msg, 0);
694 buffer_put_int(&e->output, buffer_len(&msg));
695 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
696 buffer_free(&msg);
697 }
698
699 #ifdef ENABLE_PKCS11
700 static void
701 process_add_smartcard_key(SocketEntry *e)
702 {
703 char *provider = NULL, *pin;
704 int i, type, version, count = 0, success = 0, death = 0, confirm = 0;
705 Key **keys = NULL, *k;
706 Identity *id;
707 Idtab *tab;
708
709 provider = buffer_get_string(&e->request, NULL);
710 pin = buffer_get_string(&e->request, NULL);
711
712 while (buffer_len(&e->request)) {
713 switch ((type = buffer_get_char(&e->request))) {
714 case SSH_AGENT_CONSTRAIN_LIFETIME:
715 death = time(NULL) + buffer_get_int(&e->request);
716 break;
717 case SSH_AGENT_CONSTRAIN_CONFIRM:
718 confirm = 1;
719 break;
720 default:
721 error("process_add_smartcard_key: "
722 "Unknown constraint type %d", type);
723 goto send;
724 }
725 }
726 if (lifetime && !death)
727 death = time(NULL) + lifetime;
728
729 count = pkcs11_add_provider(provider, pin, &keys);
730 for (i = 0; i < count; i++) {
731 k = keys[i];
732 version = k->type == KEY_RSA1 ? 1 : 2;
733 tab = idtab_lookup(version);
734 if (lookup_identity(k, version) == NULL) {
735 id = xcalloc(1, sizeof(Identity));
736 id->key = k;
737 id->provider = xstrdup(provider);
738 id->comment = xstrdup(provider); /* XXX */
739 id->death = death;
740 id->confirm = confirm;
741 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
742 tab->nentries++;
743 success = 1;
744 } else {
745 key_free(k);
746 }
747 keys[i] = NULL;
748 }
749 send:
750 if (pin)
751 xfree(pin);
752 if (provider)
753 xfree(provider);
754 if (keys)
755 xfree(keys);
756 buffer_put_int(&e->output, 1);
757 buffer_put_char(&e->output,
758 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
759 }
760
761 static void
762 process_remove_smartcard_key(SocketEntry *e)
763 {
764 char *provider = NULL, *pin = NULL;
765 int version, success = 0;
766 Identity *id, *nxt;
767 Idtab *tab;
768
769 provider = buffer_get_string(&e->request, NULL);
770 pin = buffer_get_string(&e->request, NULL);
771 xfree(pin);
772
773 for (version = 1; version < 3; version++) {
774 tab = idtab_lookup(version);
775 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
776 nxt = TAILQ_NEXT(id, next);
777 if (!strcmp(provider, id->provider)) {
778 TAILQ_REMOVE(&tab->idlist, id, next);
779 free_identity(id);
780 tab->nentries--;
781 }
782 }
783 }
784 if (pkcs11_del_provider(provider) == 0)
785 success = 1;
786 else
787 error("process_remove_smartcard_key:"
788 " pkcs11_del_provider failed");
789 xfree(provider);
790 buffer_put_int(&e->output, 1);
791 buffer_put_char(&e->output,
792 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
793 }
794 #endif /* ENABLE_PKCS11 */
795
796 /* dispatch incoming messages */
797
798 static void
799 process_message(SocketEntry *e)
800 {
801 u_int msg_len, type;
802 u_char *cp;
803
804 if (buffer_len(&e->input) < 5)
805 return; /* Incomplete message. */
806 cp = buffer_ptr(&e->input);
807 msg_len = get_u32(cp);
808 if (msg_len > 256 * 1024) {
809 close_socket(e);
810 return;
811 }
812 if (buffer_len(&e->input) < msg_len + 4)
813 return;
814
815 /* move the current input to e->request */
816 buffer_consume(&e->input, 4);
817 buffer_clear(&e->request);
818 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
819 buffer_consume(&e->input, msg_len);
820 type = buffer_get_char(&e->request);
821
822 /* check wheter agent is locked */
823 if (locked && type != SSH_AGENTC_UNLOCK) {
824 buffer_clear(&e->request);
825 switch (type) {
826 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
827 case SSH2_AGENTC_REQUEST_IDENTITIES:
828 /* send empty lists */
829 no_identities(e, type);
830 break;
831 default:
832 /* send a fail message for all other request types */
833 buffer_put_int(&e->output, 1);
834 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
835 }
836 return;
837 }
838
839 debug("type %d", type);
840 switch (type) {
841 case SSH_AGENTC_LOCK:
842 case SSH_AGENTC_UNLOCK:
843 process_lock_agent(e, type == SSH_AGENTC_LOCK);
844 break;
845 /* ssh1 */
846 case SSH_AGENTC_RSA_CHALLENGE:
847 process_authentication_challenge1(e);
848 break;
849 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
850 process_request_identities(e, 1);
851 break;
852 case SSH_AGENTC_ADD_RSA_IDENTITY:
853 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
854 process_add_identity(e, 1);
855 break;
856 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
857 process_remove_identity(e, 1);
858 break;
859 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
860 process_remove_all_identities(e, 1);
861 break;
862 /* ssh2 */
863 case SSH2_AGENTC_SIGN_REQUEST:
864 process_sign_request2(e);
865 break;
866 case SSH2_AGENTC_REQUEST_IDENTITIES:
867 process_request_identities(e, 2);
868 break;
869 case SSH2_AGENTC_ADD_IDENTITY:
870 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
871 process_add_identity(e, 2);
872 break;
873 case SSH2_AGENTC_REMOVE_IDENTITY:
874 process_remove_identity(e, 2);
875 break;
876 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
877 process_remove_all_identities(e, 2);
878 break;
879 #ifdef ENABLE_PKCS11
880 case SSH_AGENTC_ADD_SMARTCARD_KEY:
881 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
882 process_add_smartcard_key(e);
883 break;
884 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
885 process_remove_smartcard_key(e);
886 break;
887 #endif /* ENABLE_PKCS11 */
888 default:
889 /* Unknown message. Respond with failure. */
890 error("Unknown message %d", type);
891 buffer_clear(&e->request);
892 buffer_put_int(&e->output, 1);
893 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
894 break;
895 }
896 }
897
898 static void
899 new_socket(sock_type type, int fd)
900 {
901 u_int i, old_alloc, new_alloc;
902
903 set_nonblock(fd);
904
905 if (fd > max_fd)
906 max_fd = fd;
907
908 for (i = 0; i < sockets_alloc; i++)
909 if (sockets[i].type == AUTH_UNUSED) {
910 sockets[i].fd = fd;
911 buffer_init(&sockets[i].input);
912 buffer_init(&sockets[i].output);
913 buffer_init(&sockets[i].request);
914 sockets[i].type = type;
915 return;
916 }
917 old_alloc = sockets_alloc;
918 new_alloc = sockets_alloc + 10;
919 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
920 for (i = old_alloc; i < new_alloc; i++)
921 sockets[i].type = AUTH_UNUSED;
922 sockets_alloc = new_alloc;
923 sockets[old_alloc].fd = fd;
924 buffer_init(&sockets[old_alloc].input);
925 buffer_init(&sockets[old_alloc].output);
926 buffer_init(&sockets[old_alloc].request);
927 sockets[old_alloc].type = type;
928 }
929
930 static int
931 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
932 struct timeval **tvpp)
933 {
934 u_int i, sz, deadline;
935 int n = 0;
936 static struct timeval tv;
937
938 for (i = 0; i < sockets_alloc; i++) {
939 switch (sockets[i].type) {
940 case AUTH_SOCKET:
941 case AUTH_CONNECTION:
942 n = MAX(n, sockets[i].fd);
943 break;
944 case AUTH_UNUSED:
945 break;
946 default:
947 fatal("Unknown socket type %d", sockets[i].type);
948 break;
949 }
950 }
951
952 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
953 if (*fdrp == NULL || sz > *nallocp) {
954 if (*fdrp)
955 xfree(*fdrp);
956 if (*fdwp)
957 xfree(*fdwp);
958 *fdrp = xmalloc(sz);
959 *fdwp = xmalloc(sz);
960 *nallocp = sz;
961 }
962 if (n < *fdl)
963 debug("XXX shrink: %d < %d", n, *fdl);
964 *fdl = n;
965 memset(*fdrp, 0, sz);
966 memset(*fdwp, 0, sz);
967
968 for (i = 0; i < sockets_alloc; i++) {
969 switch (sockets[i].type) {
970 case AUTH_SOCKET:
971 case AUTH_CONNECTION:
972 FD_SET(sockets[i].fd, *fdrp);
973 if (buffer_len(&sockets[i].output) > 0)
974 FD_SET(sockets[i].fd, *fdwp);
975 break;
976 default:
977 break;
978 }
979 }
980 deadline = reaper();
981 if (parent_alive_interval != 0)
982 deadline = (deadline == 0) ? parent_alive_interval :
983 MIN(deadline, parent_alive_interval);
984 if (deadline == 0) {
985 *tvpp = NULL;
986 } else {
987 tv.tv_sec = deadline;
988 tv.tv_usec = 0;
989 *tvpp = &tv;
990 }
991 return (1);
992 }
993
994 static void
995 after_select(fd_set *readset, fd_set *writeset)
996 {
997 struct sockaddr_un sunaddr;
998 socklen_t slen;
999 char buf[1024];
1000 int len, sock;
1001 u_int i, orig_alloc;
1002 uid_t euid;
1003 gid_t egid;
1004
1005 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
1006 switch (sockets[i].type) {
1007 case AUTH_UNUSED:
1008 break;
1009 case AUTH_SOCKET:
1010 if (FD_ISSET(sockets[i].fd, readset)) {
1011 slen = sizeof(sunaddr);
1012 sock = accept(sockets[i].fd,
1013 (struct sockaddr *)&sunaddr, &slen);
1014 if (sock < 0) {
1015 error("accept from AUTH_SOCKET: %s",
1016 strerror(errno));
1017 break;
1018 }
1019 if (getpeereid(sock, &euid, &egid) < 0) {
1020 error("getpeereid %d failed: %s",
1021 sock, strerror(errno));
1022 close(sock);
1023 break;
1024 }
1025 if ((euid != 0) && (getuid() != euid)) {
1026 error("uid mismatch: "
1027 "peer euid %u != uid %u",
1028 (u_int) euid, (u_int) getuid());
1029 close(sock);
1030 break;
1031 }
1032 new_socket(AUTH_CONNECTION, sock);
1033 }
1034 break;
1035 case AUTH_CONNECTION:
1036 if (buffer_len(&sockets[i].output) > 0 &&
1037 FD_ISSET(sockets[i].fd, writeset)) {
1038 len = write(sockets[i].fd,
1039 buffer_ptr(&sockets[i].output),
1040 buffer_len(&sockets[i].output));
1041 if (len == -1 && (errno == EAGAIN ||
1042 errno == EWOULDBLOCK ||
1043 errno == EINTR))
1044 continue;
1045 if (len <= 0) {
1046 close_socket(&sockets[i]);
1047 break;
1048 }
1049 buffer_consume(&sockets[i].output, len);
1050 }
1051 if (FD_ISSET(sockets[i].fd, readset)) {
1052 len = read(sockets[i].fd, buf, sizeof(buf));
1053 if (len == -1 && (errno == EAGAIN ||
1054 errno == EWOULDBLOCK ||
1055 errno == EINTR))
1056 continue;
1057 if (len <= 0) {
1058 close_socket(&sockets[i]);
1059 break;
1060 }
1061 buffer_append(&sockets[i].input, buf, len);
1062 process_message(&sockets[i]);
1063 }
1064 break;
1065 default:
1066 fatal("Unknown type %d", sockets[i].type);
1067 }
1068 }
1069
1070 static void
1071 cleanup_socket(void)
1072 {
1073 if (socket_name[0])
1074 unlink(socket_name);
1075 if (socket_dir[0])
1076 rmdir(socket_dir);
1077 }
1078
1079 void
1080 cleanup_exit(int i)
1081 {
1082 cleanup_socket();
1083 _exit(i);
1084 }
1085
1086 /*ARGSUSED*/
1087 static void
1088 cleanup_handler(int sig)
1089 {
1090 cleanup_socket();
1091 #ifdef ENABLE_PKCS11
1092 pkcs11_terminate();
1093 #endif
1094 _exit(2);
1095 }
1096
1097 static void
1098 check_parent_exists(void)
1099 {
1100 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1101 /* printf("Parent has died - Authentication agent exiting.\n"); */
1102 cleanup_socket();
1103 _exit(2);
1104 }
1105 }
1106
1107 static void
1108 usage(void)
1109 {
1110 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1111 __progname);
1112 fprintf(stderr, "Options:\n");
1113 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1114 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1115 fprintf(stderr, " -k Kill the current agent.\n");
1116 fprintf(stderr, " -d Debug mode.\n");
1117 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1118 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1119 exit(1);
1120 }
1121
1122 int
1123 main(int ac, char **av)
1124 {
1125 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1126 int sock, fd, ch, result, saved_errno;
1127 u_int nalloc;
1128 char *shell, *format, *pidstr, *agentsocket = NULL;
1129 fd_set *readsetp = NULL, *writesetp = NULL;
1130 struct sockaddr_un sunaddr;
1131 #ifdef HAVE_SETRLIMIT
1132 struct rlimit rlim;
1133 #endif
1134 int prev_mask;
1135 extern int optind;
1136 extern char *optarg;
1137 pid_t pid;
1138 char pidstrbuf[1 + 3 * sizeof pid];
1139 struct timeval *tvp = NULL;
1140 size_t len;
1141
1142 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1143 sanitise_stdfd();
1144
1145 /* drop */
1146 setegid(getgid());
1147 setgid(getgid());
1148
1149 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1150 /* Disable ptrace on Linux without sgid bit */
1151 prctl(PR_SET_DUMPABLE, 0);
1152 #endif
1153
1154 OpenSSL_add_all_algorithms();
1155
1156 __progname = ssh_get_progname(av[0]);
1157 init_rng();
1158 seed_rng();
1159
1160 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1161 switch (ch) {
1162 case 'c':
1163 if (s_flag)
1164 usage();
1165 c_flag++;
1166 break;
1167 case 'k':
1168 k_flag++;
1169 break;
1170 case 's':
1171 if (c_flag)
1172 usage();
1173 s_flag++;
1174 break;
1175 case 'd':
1176 if (d_flag)
1177 usage();
1178 d_flag++;
1179 break;
1180 case 'a':
1181 agentsocket = optarg;
1182 break;
1183 case 't':
1184 if ((lifetime = convtime(optarg)) == -1) {
1185 fprintf(stderr, "Invalid lifetime\n");
1186 usage();
1187 }
1188 break;
1189 default:
1190 usage();
1191 }
1192 }
1193 ac -= optind;
1194 av += optind;
1195
1196 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1197 usage();
1198
1199 if (ac == 0 && !c_flag && !s_flag) {
1200 shell = getenv("SHELL");
1201 if (shell != NULL && (len = strlen(shell)) > 2 &&
1202 strncmp(shell + len - 3, "csh", 3) == 0)
1203 c_flag = 1;
1204 }
1205 if (k_flag) {
1206 const char *errstr = NULL;
1207
1208 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1209 if (pidstr == NULL) {
1210 fprintf(stderr, "%s not set, cannot kill agent\n",
1211 SSH_AGENTPID_ENV_NAME);
1212 exit(1);
1213 }
1214 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1215 if (errstr) {
1216 fprintf(stderr,
1217 "%s=\"%s\", which is not a good PID: %s\n",
1218 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1219 exit(1);
1220 }
1221 if (kill(pid, SIGTERM) == -1) {
1222 perror("kill");
1223 exit(1);
1224 }
1225 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1226 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1227 printf(format, SSH_AGENTPID_ENV_NAME);
1228 printf("echo Agent pid %ld killed;\n", (long)pid);
1229 exit(0);
1230 }
1231 parent_pid = getpid();
1232
1233 if (agentsocket == NULL) {
1234 /* Create private directory for agent socket */
1235 mktemp_proto(socket_dir, sizeof(socket_dir));
1236 if (mkdtemp(socket_dir) == NULL) {
1237 perror("mkdtemp: private socket dir");
1238 exit(1);
1239 }
1240 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1241 (long)parent_pid);
1242 } else {
1243 /* Try to use specified agent socket */
1244 socket_dir[0] = '\0';
1245 strlcpy(socket_name, agentsocket, sizeof socket_name);
1246 }
1247
1248 /*
1249 * Create socket early so it will exist before command gets run from
1250 * the parent.
1251 */
1252 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1253 if (sock < 0) {
1254 perror("socket");
1255 *socket_name = '\0'; /* Don't unlink any existing file */
1256 cleanup_exit(1);
1257 }
1258 memset(&sunaddr, 0, sizeof(sunaddr));
1259 sunaddr.sun_family = AF_UNIX;
1260 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1261 prev_mask = umask(0177);
1262 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1263 perror("bind");
1264 *socket_name = '\0'; /* Don't unlink any existing file */
1265 umask(prev_mask);
1266 cleanup_exit(1);
1267 }
1268 umask(prev_mask);
1269 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1270 perror("listen");
1271 cleanup_exit(1);
1272 }
1273
1274 /*
1275 * Fork, and have the parent execute the command, if any, or present
1276 * the socket data. The child continues as the authentication agent.
1277 */
1278 if (d_flag) {
1279 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1280 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1281 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1282 SSH_AUTHSOCKET_ENV_NAME);
1283 printf("echo Agent pid %ld;\n", (long)parent_pid);
1284 goto skip;
1285 }
1286 pid = fork();
1287 if (pid == -1) {
1288 perror("fork");
1289 cleanup_exit(1);
1290 }
1291 if (pid != 0) { /* Parent - execute the given command. */
1292 close(sock);
1293 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1294 if (ac == 0) {
1295 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1296 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1297 SSH_AUTHSOCKET_ENV_NAME);
1298 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1299 SSH_AGENTPID_ENV_NAME);
1300 printf("echo Agent pid %ld;\n", (long)pid);
1301 exit(0);
1302 }
1303 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1304 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1305 perror("setenv");
1306 exit(1);
1307 }
1308 execvp(av[0], av);
1309 perror(av[0]);
1310 exit(1);
1311 }
1312 /* child */
1313 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1314
1315 if (setsid() == -1) {
1316 error("setsid: %s", strerror(errno));
1317 cleanup_exit(1);
1318 }
1319
1320 (void)chdir("/");
1321 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1322 /* XXX might close listen socket */
1323 (void)dup2(fd, STDIN_FILENO);
1324 (void)dup2(fd, STDOUT_FILENO);
1325 (void)dup2(fd, STDERR_FILENO);
1326 if (fd > 2)
1327 close(fd);
1328 }
1329
1330 #ifdef HAVE_SETRLIMIT
1331 /* deny core dumps, since memory contains unencrypted private keys */
1332 rlim.rlim_cur = rlim.rlim_max = 0;
1333 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1334 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1335 cleanup_exit(1);
1336 }
1337 #endif
1338
1339 skip:
1340
1341 #ifdef ENABLE_PKCS11
1342 pkcs11_init(0);
1343 #endif
1344 new_socket(AUTH_SOCKET, sock);
1345 if (ac > 0)
1346 parent_alive_interval = 10;
1347 idtab_init();
1348 if (!d_flag)
1349 signal(SIGINT, SIG_IGN);
1350 signal(SIGPIPE, SIG_IGN);
1351 signal(SIGHUP, cleanup_handler);
1352 signal(SIGTERM, cleanup_handler);
1353 nalloc = 0;
1354
1355 while (1) {
1356 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1357 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1358 saved_errno = errno;
1359 if (parent_alive_interval != 0)
1360 check_parent_exists();
1361 (void) reaper(); /* remove expired keys */
1362 if (result < 0) {
1363 if (saved_errno == EINTR)
1364 continue;
1365 fatal("select: %s", strerror(saved_errno));
1366 } else if (result > 0)
1367 after_select(readsetp, writesetp);
1368 }
1369 /* NOTREACHED */
1370 }
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