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- markus@cvs.openbsd.org 2005/06/16 08:00:00
[openssh-git.git] / ssh-agent.c
blobdd7e22ad5ade39924351bd19f030e658f842309b
1 /*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 * The authentication agent program.
6 *
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
12 *
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36 #include "includes.h"
37 #include "openbsd-compat/sys-queue.h"
38 RCSID("$OpenBSD: ssh-agent.c,v 1.122 2004/10/29 22:53:56 djm Exp $");
39
40 #include <openssl/evp.h>
41 #include <openssl/md5.h>
42
43 #include "ssh.h"
44 #include "rsa.h"
45 #include "buffer.h"
46 #include "bufaux.h"
47 #include "xmalloc.h"
48 #include "getput.h"
49 #include "key.h"
50 #include "authfd.h"
51 #include "compat.h"
52 #include "log.h"
53 #include "misc.h"
54
55 #ifdef SMARTCARD
56 #include "scard.h"
57 #endif
58
59 #if defined(HAVE_SYS_PRCTL_H)
60 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
61 #endif
62
63 typedef enum {
64 AUTH_UNUSED,
65 AUTH_SOCKET,
66 AUTH_CONNECTION
67 } sock_type;
68
69 typedef struct {
70 int fd;
71 sock_type type;
72 Buffer input;
73 Buffer output;
74 Buffer request;
75 } SocketEntry;
76
77 u_int sockets_alloc = 0;
78 SocketEntry *sockets = NULL;
79
80 typedef struct identity {
81 TAILQ_ENTRY(identity) next;
82 Key *key;
83 char *comment;
84 u_int death;
85 u_int confirm;
86 } Identity;
87
88 typedef struct {
89 int nentries;
90 TAILQ_HEAD(idqueue, identity) idlist;
91 } Idtab;
92
93 /* private key table, one per protocol version */
94 Idtab idtable[3];
95
96 int max_fd = 0;
97
98 /* pid of shell == parent of agent */
99 pid_t parent_pid = -1;
100
101 /* pathname and directory for AUTH_SOCKET */
102 char socket_name[1024];
103 char socket_dir[1024];
104
105 /* locking */
106 int locked = 0;
107 char *lock_passwd = NULL;
108
109 extern char *__progname;
110
111 /* Default lifetime (0 == forever) */
112 static int lifetime = 0;
113
114 static void
115 close_socket(SocketEntry *e)
116 {
117 close(e->fd);
118 e->fd = -1;
119 e->type = AUTH_UNUSED;
120 buffer_free(&e->input);
121 buffer_free(&e->output);
122 buffer_free(&e->request);
123 }
124
125 static void
126 idtab_init(void)
127 {
128 int i;
129
130 for (i = 0; i <=2; i++) {
131 TAILQ_INIT(&idtable[i].idlist);
132 idtable[i].nentries = 0;
133 }
134 }
135
136 /* return private key table for requested protocol version */
137 static Idtab *
138 idtab_lookup(int version)
139 {
140 if (version < 1 || version > 2)
141 fatal("internal error, bad protocol version %d", version);
142 return &idtable[version];
143 }
144
145 static void
146 free_identity(Identity *id)
147 {
148 key_free(id->key);
149 xfree(id->comment);
150 xfree(id);
151 }
152
153 /* return matching private key for given public key */
154 static Identity *
155 lookup_identity(Key *key, int version)
156 {
157 Identity *id;
158
159 Idtab *tab = idtab_lookup(version);
160 TAILQ_FOREACH(id, &tab->idlist, next) {
161 if (key_equal(key, id->key))
162 return (id);
163 }
164 return (NULL);
165 }
166
167 /* Check confirmation of keysign request */
168 static int
169 confirm_key(Identity *id)
170 {
171 char *p;
172 int ret = -1;
173
174 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
175 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
176 id->comment, p))
177 ret = 0;
178 xfree(p);
179
180 return (ret);
181 }
182
183 /* send list of supported public keys to 'client' */
184 static void
185 process_request_identities(SocketEntry *e, int version)
186 {
187 Idtab *tab = idtab_lookup(version);
188 Identity *id;
189 Buffer msg;
190
191 buffer_init(&msg);
192 buffer_put_char(&msg, (version == 1) ?
193 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
194 buffer_put_int(&msg, tab->nentries);
195 TAILQ_FOREACH(id, &tab->idlist, next) {
196 if (id->key->type == KEY_RSA1) {
197 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
198 buffer_put_bignum(&msg, id->key->rsa->e);
199 buffer_put_bignum(&msg, id->key->rsa->n);
200 } else {
201 u_char *blob;
202 u_int blen;
203 key_to_blob(id->key, &blob, &blen);
204 buffer_put_string(&msg, blob, blen);
205 xfree(blob);
206 }
207 buffer_put_cstring(&msg, id->comment);
208 }
209 buffer_put_int(&e->output, buffer_len(&msg));
210 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
211 buffer_free(&msg);
212 }
213
214 /* ssh1 only */
215 static void
216 process_authentication_challenge1(SocketEntry *e)
217 {
218 u_char buf[32], mdbuf[16], session_id[16];
219 u_int response_type;
220 BIGNUM *challenge;
221 Identity *id;
222 int i, len;
223 Buffer msg;
224 MD5_CTX md;
225 Key *key;
226
227 buffer_init(&msg);
228 key = key_new(KEY_RSA1);
229 if ((challenge = BN_new()) == NULL)
230 fatal("process_authentication_challenge1: BN_new failed");
231
232 (void) buffer_get_int(&e->request); /* ignored */
233 buffer_get_bignum(&e->request, key->rsa->e);
234 buffer_get_bignum(&e->request, key->rsa->n);
235 buffer_get_bignum(&e->request, challenge);
236
237 /* Only protocol 1.1 is supported */
238 if (buffer_len(&e->request) == 0)
239 goto failure;
240 buffer_get(&e->request, session_id, 16);
241 response_type = buffer_get_int(&e->request);
242 if (response_type != 1)
243 goto failure;
244
245 id = lookup_identity(key, 1);
246 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
247 Key *private = id->key;
248 /* Decrypt the challenge using the private key. */
249 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
250 goto failure;
251
252 /* The response is MD5 of decrypted challenge plus session id. */
253 len = BN_num_bytes(challenge);
254 if (len <= 0 || len > 32) {
255 logit("process_authentication_challenge: bad challenge length %d", len);
256 goto failure;
257 }
258 memset(buf, 0, 32);
259 BN_bn2bin(challenge, buf + 32 - len);
260 MD5_Init(&md);
261 MD5_Update(&md, buf, 32);
262 MD5_Update(&md, session_id, 16);
263 MD5_Final(mdbuf, &md);
264
265 /* Send the response. */
266 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
267 for (i = 0; i < 16; i++)
268 buffer_put_char(&msg, mdbuf[i]);
269 goto send;
270 }
271
272 failure:
273 /* Unknown identity or protocol error. Send failure. */
274 buffer_put_char(&msg, SSH_AGENT_FAILURE);
275 send:
276 buffer_put_int(&e->output, buffer_len(&msg));
277 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
278 key_free(key);
279 BN_clear_free(challenge);
280 buffer_free(&msg);
281 }
282
283 /* ssh2 only */
284 static void
285 process_sign_request2(SocketEntry *e)
286 {
287 u_char *blob, *data, *signature = NULL;
288 u_int blen, dlen, slen = 0;
289 extern int datafellows;
290 int ok = -1, flags;
291 Buffer msg;
292 Key *key;
293
294 datafellows = 0;
295
296 blob = buffer_get_string(&e->request, &blen);
297 data = buffer_get_string(&e->request, &dlen);
298
299 flags = buffer_get_int(&e->request);
300 if (flags & SSH_AGENT_OLD_SIGNATURE)
301 datafellows = SSH_BUG_SIGBLOB;
302
303 key = key_from_blob(blob, blen);
304 if (key != NULL) {
305 Identity *id = lookup_identity(key, 2);
306 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
307 ok = key_sign(id->key, &signature, &slen, data, dlen);
308 }
309 key_free(key);
310 buffer_init(&msg);
311 if (ok == 0) {
312 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
313 buffer_put_string(&msg, signature, slen);
314 } else {
315 buffer_put_char(&msg, SSH_AGENT_FAILURE);
316 }
317 buffer_put_int(&e->output, buffer_len(&msg));
318 buffer_append(&e->output, buffer_ptr(&msg),
319 buffer_len(&msg));
320 buffer_free(&msg);
321 xfree(data);
322 xfree(blob);
323 if (signature != NULL)
324 xfree(signature);
325 }
326
327 /* shared */
328 static void
329 process_remove_identity(SocketEntry *e, int version)
330 {
331 u_int blen, bits;
332 int success = 0;
333 Key *key = NULL;
334 u_char *blob;
335
336 switch (version) {
337 case 1:
338 key = key_new(KEY_RSA1);
339 bits = buffer_get_int(&e->request);
340 buffer_get_bignum(&e->request, key->rsa->e);
341 buffer_get_bignum(&e->request, key->rsa->n);
342
343 if (bits != key_size(key))
344 logit("Warning: identity keysize mismatch: actual %u, announced %u",
345 key_size(key), bits);
346 break;
347 case 2:
348 blob = buffer_get_string(&e->request, &blen);
349 key = key_from_blob(blob, blen);
350 xfree(blob);
351 break;
352 }
353 if (key != NULL) {
354 Identity *id = lookup_identity(key, version);
355 if (id != NULL) {
356 /*
357 * We have this key. Free the old key. Since we
358 * don\'t want to leave empty slots in the middle of
359 * the array, we actually free the key there and move
360 * all the entries between the empty slot and the end
361 * of the array.
362 */
363 Idtab *tab = idtab_lookup(version);
364 if (tab->nentries < 1)
365 fatal("process_remove_identity: "
366 "internal error: tab->nentries %d",
367 tab->nentries);
368 TAILQ_REMOVE(&tab->idlist, id, next);
369 free_identity(id);
370 tab->nentries--;
371 success = 1;
372 }
373 key_free(key);
374 }
375 buffer_put_int(&e->output, 1);
376 buffer_put_char(&e->output,
377 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
378 }
379
380 static void
381 process_remove_all_identities(SocketEntry *e, int version)
382 {
383 Idtab *tab = idtab_lookup(version);
384 Identity *id;
385
386 /* Loop over all identities and clear the keys. */
387 for (id = TAILQ_FIRST(&tab->idlist); id;
388 id = TAILQ_FIRST(&tab->idlist)) {
389 TAILQ_REMOVE(&tab->idlist, id, next);
390 free_identity(id);
391 }
392
393 /* Mark that there are no identities. */
394 tab->nentries = 0;
395
396 /* Send success. */
397 buffer_put_int(&e->output, 1);
398 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
399 }
400
401 static void
402 reaper(void)
403 {
404 u_int now = time(NULL);
405 Identity *id, *nxt;
406 int version;
407 Idtab *tab;
408
409 for (version = 1; version < 3; version++) {
410 tab = idtab_lookup(version);
411 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
412 nxt = TAILQ_NEXT(id, next);
413 if (id->death != 0 && now >= id->death) {
414 TAILQ_REMOVE(&tab->idlist, id, next);
415 free_identity(id);
416 tab->nentries--;
417 }
418 }
419 }
420 }
421
422 static void
423 process_add_identity(SocketEntry *e, int version)
424 {
425 Idtab *tab = idtab_lookup(version);
426 int type, success = 0, death = 0, confirm = 0;
427 char *type_name, *comment;
428 Key *k = NULL;
429
430 switch (version) {
431 case 1:
432 k = key_new_private(KEY_RSA1);
433 (void) buffer_get_int(&e->request); /* ignored */
434 buffer_get_bignum(&e->request, k->rsa->n);
435 buffer_get_bignum(&e->request, k->rsa->e);
436 buffer_get_bignum(&e->request, k->rsa->d);
437 buffer_get_bignum(&e->request, k->rsa->iqmp);
438
439 /* SSH and SSL have p and q swapped */
440 buffer_get_bignum(&e->request, k->rsa->q); /* p */
441 buffer_get_bignum(&e->request, k->rsa->p); /* q */
442
443 /* Generate additional parameters */
444 rsa_generate_additional_parameters(k->rsa);
445 break;
446 case 2:
447 type_name = buffer_get_string(&e->request, NULL);
448 type = key_type_from_name(type_name);
449 xfree(type_name);
450 switch (type) {
451 case KEY_DSA:
452 k = key_new_private(type);
453 buffer_get_bignum2(&e->request, k->dsa->p);
454 buffer_get_bignum2(&e->request, k->dsa->q);
455 buffer_get_bignum2(&e->request, k->dsa->g);
456 buffer_get_bignum2(&e->request, k->dsa->pub_key);
457 buffer_get_bignum2(&e->request, k->dsa->priv_key);
458 break;
459 case KEY_RSA:
460 k = key_new_private(type);
461 buffer_get_bignum2(&e->request, k->rsa->n);
462 buffer_get_bignum2(&e->request, k->rsa->e);
463 buffer_get_bignum2(&e->request, k->rsa->d);
464 buffer_get_bignum2(&e->request, k->rsa->iqmp);
465 buffer_get_bignum2(&e->request, k->rsa->p);
466 buffer_get_bignum2(&e->request, k->rsa->q);
467
468 /* Generate additional parameters */
469 rsa_generate_additional_parameters(k->rsa);
470 break;
471 default:
472 buffer_clear(&e->request);
473 goto send;
474 }
475 break;
476 }
477 /* enable blinding */
478 switch (k->type) {
479 case KEY_RSA:
480 case KEY_RSA1:
481 if (RSA_blinding_on(k->rsa, NULL) != 1) {
482 error("process_add_identity: RSA_blinding_on failed");
483 key_free(k);
484 goto send;
485 }
486 break;
487 }
488 comment = buffer_get_string(&e->request, NULL);
489 if (k == NULL) {
490 xfree(comment);
491 goto send;
492 }
493 success = 1;
494 while (buffer_len(&e->request)) {
495 switch (buffer_get_char(&e->request)) {
496 case SSH_AGENT_CONSTRAIN_LIFETIME:
497 death = time(NULL) + buffer_get_int(&e->request);
498 break;
499 case SSH_AGENT_CONSTRAIN_CONFIRM:
500 confirm = 1;
501 break;
502 default:
503 break;
504 }
505 }
506 if (lifetime && !death)
507 death = time(NULL) + lifetime;
508 if (lookup_identity(k, version) == NULL) {
509 Identity *id = xmalloc(sizeof(Identity));
510 id->key = k;
511 id->comment = comment;
512 id->death = death;
513 id->confirm = confirm;
514 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
515 /* Increment the number of identities. */
516 tab->nentries++;
517 } else {
518 key_free(k);
519 xfree(comment);
520 }
521 send:
522 buffer_put_int(&e->output, 1);
523 buffer_put_char(&e->output,
524 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
525 }
526
527 /* XXX todo: encrypt sensitive data with passphrase */
528 static void
529 process_lock_agent(SocketEntry *e, int lock)
530 {
531 int success = 0;
532 char *passwd;
533
534 passwd = buffer_get_string(&e->request, NULL);
535 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
536 locked = 0;
537 memset(lock_passwd, 0, strlen(lock_passwd));
538 xfree(lock_passwd);
539 lock_passwd = NULL;
540 success = 1;
541 } else if (!locked && lock) {
542 locked = 1;
543 lock_passwd = xstrdup(passwd);
544 success = 1;
545 }
546 memset(passwd, 0, strlen(passwd));
547 xfree(passwd);
548
549 buffer_put_int(&e->output, 1);
550 buffer_put_char(&e->output,
551 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
552 }
553
554 static void
555 no_identities(SocketEntry *e, u_int type)
556 {
557 Buffer msg;
558
559 buffer_init(&msg);
560 buffer_put_char(&msg,
561 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
562 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
563 buffer_put_int(&msg, 0);
564 buffer_put_int(&e->output, buffer_len(&msg));
565 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
566 buffer_free(&msg);
567 }
568
569 #ifdef SMARTCARD
570 static void
571 process_add_smartcard_key (SocketEntry *e)
572 {
573 char *sc_reader_id = NULL, *pin;
574 int i, version, success = 0, death = 0, confirm = 0;
575 Key **keys, *k;
576 Identity *id;
577 Idtab *tab;
578
579 sc_reader_id = buffer_get_string(&e->request, NULL);
580 pin = buffer_get_string(&e->request, NULL);
581
582 while (buffer_len(&e->request)) {
583 switch (buffer_get_char(&e->request)) {
584 case SSH_AGENT_CONSTRAIN_LIFETIME:
585 death = time(NULL) + buffer_get_int(&e->request);
586 break;
587 case SSH_AGENT_CONSTRAIN_CONFIRM:
588 confirm = 1;
589 break;
590 default:
591 break;
592 }
593 }
594 if (lifetime && !death)
595 death = time(NULL) + lifetime;
596
597 keys = sc_get_keys(sc_reader_id, pin);
598 xfree(sc_reader_id);
599 xfree(pin);
600
601 if (keys == NULL || keys[0] == NULL) {
602 error("sc_get_keys failed");
603 goto send;
604 }
605 for (i = 0; keys[i] != NULL; i++) {
606 k = keys[i];
607 version = k->type == KEY_RSA1 ? 1 : 2;
608 tab = idtab_lookup(version);
609 if (lookup_identity(k, version) == NULL) {
610 id = xmalloc(sizeof(Identity));
611 id->key = k;
612 id->comment = sc_get_key_label(k);
613 id->death = death;
614 id->confirm = confirm;
615 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
616 tab->nentries++;
617 success = 1;
618 } else {
619 key_free(k);
620 }
621 keys[i] = NULL;
622 }
623 xfree(keys);
624 send:
625 buffer_put_int(&e->output, 1);
626 buffer_put_char(&e->output,
627 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
628 }
629
630 static void
631 process_remove_smartcard_key(SocketEntry *e)
632 {
633 char *sc_reader_id = NULL, *pin;
634 int i, version, success = 0;
635 Key **keys, *k = NULL;
636 Identity *id;
637 Idtab *tab;
638
639 sc_reader_id = buffer_get_string(&e->request, NULL);
640 pin = buffer_get_string(&e->request, NULL);
641 keys = sc_get_keys(sc_reader_id, pin);
642 xfree(sc_reader_id);
643 xfree(pin);
644
645 if (keys == NULL || keys[0] == NULL) {
646 error("sc_get_keys failed");
647 goto send;
648 }
649 for (i = 0; keys[i] != NULL; i++) {
650 k = keys[i];
651 version = k->type == KEY_RSA1 ? 1 : 2;
652 if ((id = lookup_identity(k, version)) != NULL) {
653 tab = idtab_lookup(version);
654 TAILQ_REMOVE(&tab->idlist, id, next);
655 tab->nentries--;
656 free_identity(id);
657 success = 1;
658 }
659 key_free(k);
660 keys[i] = NULL;
661 }
662 xfree(keys);
663 send:
664 buffer_put_int(&e->output, 1);
665 buffer_put_char(&e->output,
666 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
667 }
668 #endif /* SMARTCARD */
669
670 /* dispatch incoming messages */
671
672 static void
673 process_message(SocketEntry *e)
674 {
675 u_int msg_len, type;
676 u_char *cp;
677
678 /* kill dead keys */
679 reaper();
680
681 if (buffer_len(&e->input) < 5)
682 return; /* Incomplete message. */
683 cp = buffer_ptr(&e->input);
684 msg_len = GET_32BIT(cp);
685 if (msg_len > 256 * 1024) {
686 close_socket(e);
687 return;
688 }
689 if (buffer_len(&e->input) < msg_len + 4)
690 return;
691
692 /* move the current input to e->request */
693 buffer_consume(&e->input, 4);
694 buffer_clear(&e->request);
695 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
696 buffer_consume(&e->input, msg_len);
697 type = buffer_get_char(&e->request);
698
699 /* check wheter agent is locked */
700 if (locked && type != SSH_AGENTC_UNLOCK) {
701 buffer_clear(&e->request);
702 switch (type) {
703 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
704 case SSH2_AGENTC_REQUEST_IDENTITIES:
705 /* send empty lists */
706 no_identities(e, type);
707 break;
708 default:
709 /* send a fail message for all other request types */
710 buffer_put_int(&e->output, 1);
711 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
712 }
713 return;
714 }
715
716 debug("type %d", type);
717 switch (type) {
718 case SSH_AGENTC_LOCK:
719 case SSH_AGENTC_UNLOCK:
720 process_lock_agent(e, type == SSH_AGENTC_LOCK);
721 break;
722 /* ssh1 */
723 case SSH_AGENTC_RSA_CHALLENGE:
724 process_authentication_challenge1(e);
725 break;
726 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
727 process_request_identities(e, 1);
728 break;
729 case SSH_AGENTC_ADD_RSA_IDENTITY:
730 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
731 process_add_identity(e, 1);
732 break;
733 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
734 process_remove_identity(e, 1);
735 break;
736 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
737 process_remove_all_identities(e, 1);
738 break;
739 /* ssh2 */
740 case SSH2_AGENTC_SIGN_REQUEST:
741 process_sign_request2(e);
742 break;
743 case SSH2_AGENTC_REQUEST_IDENTITIES:
744 process_request_identities(e, 2);
745 break;
746 case SSH2_AGENTC_ADD_IDENTITY:
747 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
748 process_add_identity(e, 2);
749 break;
750 case SSH2_AGENTC_REMOVE_IDENTITY:
751 process_remove_identity(e, 2);
752 break;
753 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
754 process_remove_all_identities(e, 2);
755 break;
756 #ifdef SMARTCARD
757 case SSH_AGENTC_ADD_SMARTCARD_KEY:
758 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
759 process_add_smartcard_key(e);
760 break;
761 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
762 process_remove_smartcard_key(e);
763 break;
764 #endif /* SMARTCARD */
765 default:
766 /* Unknown message. Respond with failure. */
767 error("Unknown message %d", type);
768 buffer_clear(&e->request);
769 buffer_put_int(&e->output, 1);
770 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
771 break;
772 }
773 }
774
775 static void
776 new_socket(sock_type type, int fd)
777 {
778 u_int i, old_alloc, new_alloc;
779
780 set_nonblock(fd);
781
782 if (fd > max_fd)
783 max_fd = fd;
784
785 for (i = 0; i < sockets_alloc; i++)
786 if (sockets[i].type == AUTH_UNUSED) {
787 sockets[i].fd = fd;
788 buffer_init(&sockets[i].input);
789 buffer_init(&sockets[i].output);
790 buffer_init(&sockets[i].request);
791 sockets[i].type = type;
792 return;
793 }
794 old_alloc = sockets_alloc;
795 new_alloc = sockets_alloc + 10;
796 if (sockets)
797 sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0]));
798 else
799 sockets = xmalloc(new_alloc * sizeof(sockets[0]));
800 for (i = old_alloc; i < new_alloc; i++)
801 sockets[i].type = AUTH_UNUSED;
802 sockets_alloc = new_alloc;
803 sockets[old_alloc].fd = fd;
804 buffer_init(&sockets[old_alloc].input);
805 buffer_init(&sockets[old_alloc].output);
806 buffer_init(&sockets[old_alloc].request);
807 sockets[old_alloc].type = type;
808 }
809
810 static int
811 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp)
812 {
813 u_int i, sz;
814 int n = 0;
815
816 for (i = 0; i < sockets_alloc; i++) {
817 switch (sockets[i].type) {
818 case AUTH_SOCKET:
819 case AUTH_CONNECTION:
820 n = MAX(n, sockets[i].fd);
821 break;
822 case AUTH_UNUSED:
823 break;
824 default:
825 fatal("Unknown socket type %d", sockets[i].type);
826 break;
827 }
828 }
829
830 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
831 if (*fdrp == NULL || sz > *nallocp) {
832 if (*fdrp)
833 xfree(*fdrp);
834 if (*fdwp)
835 xfree(*fdwp);
836 *fdrp = xmalloc(sz);
837 *fdwp = xmalloc(sz);
838 *nallocp = sz;
839 }
840 if (n < *fdl)
841 debug("XXX shrink: %d < %d", n, *fdl);
842 *fdl = n;
843 memset(*fdrp, 0, sz);
844 memset(*fdwp, 0, sz);
845
846 for (i = 0; i < sockets_alloc; i++) {
847 switch (sockets[i].type) {
848 case AUTH_SOCKET:
849 case AUTH_CONNECTION:
850 FD_SET(sockets[i].fd, *fdrp);
851 if (buffer_len(&sockets[i].output) > 0)
852 FD_SET(sockets[i].fd, *fdwp);
853 break;
854 default:
855 break;
856 }
857 }
858 return (1);
859 }
860
861 static void
862 after_select(fd_set *readset, fd_set *writeset)
863 {
864 struct sockaddr_un sunaddr;
865 socklen_t slen;
866 char buf[1024];
867 int len, sock;
868 u_int i;
869 uid_t euid;
870 gid_t egid;
871
872 for (i = 0; i < sockets_alloc; i++)
873 switch (sockets[i].type) {
874 case AUTH_UNUSED:
875 break;
876 case AUTH_SOCKET:
877 if (FD_ISSET(sockets[i].fd, readset)) {
878 slen = sizeof(sunaddr);
879 sock = accept(sockets[i].fd,
880 (struct sockaddr *) &sunaddr, &slen);
881 if (sock < 0) {
882 error("accept from AUTH_SOCKET: %s",
883 strerror(errno));
884 break;
885 }
886 if (getpeereid(sock, &euid, &egid) < 0) {
887 error("getpeereid %d failed: %s",
888 sock, strerror(errno));
889 close(sock);
890 break;
891 }
892 if ((euid != 0) && (getuid() != euid)) {
893 error("uid mismatch: "
894 "peer euid %u != uid %u",
895 (u_int) euid, (u_int) getuid());
896 close(sock);
897 break;
898 }
899 new_socket(AUTH_CONNECTION, sock);
900 }
901 break;
902 case AUTH_CONNECTION:
903 if (buffer_len(&sockets[i].output) > 0 &&
904 FD_ISSET(sockets[i].fd, writeset)) {
905 do {
906 len = write(sockets[i].fd,
907 buffer_ptr(&sockets[i].output),
908 buffer_len(&sockets[i].output));
909 if (len == -1 && (errno == EAGAIN ||
910 errno == EINTR))
911 continue;
912 break;
913 } while (1);
914 if (len <= 0) {
915 close_socket(&sockets[i]);
916 break;
917 }
918 buffer_consume(&sockets[i].output, len);
919 }
920 if (FD_ISSET(sockets[i].fd, readset)) {
921 do {
922 len = read(sockets[i].fd, buf, sizeof(buf));
923 if (len == -1 && (errno == EAGAIN ||
924 errno == EINTR))
925 continue;
926 break;
927 } while (1);
928 if (len <= 0) {
929 close_socket(&sockets[i]);
930 break;
931 }
932 buffer_append(&sockets[i].input, buf, len);
933 process_message(&sockets[i]);
934 }
935 break;
936 default:
937 fatal("Unknown type %d", sockets[i].type);
938 }
939 }
940
941 static void
942 cleanup_socket(void)
943 {
944 if (socket_name[0])
945 unlink(socket_name);
946 if (socket_dir[0])
947 rmdir(socket_dir);
948 }
949
950 void
951 cleanup_exit(int i)
952 {
953 cleanup_socket();
954 _exit(i);
955 }
956
957 static void
958 cleanup_handler(int sig)
959 {
960 cleanup_socket();
961 _exit(2);
962 }
963
964 static void
965 check_parent_exists(int sig)
966 {
967 int save_errno = errno;
968
969 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
970 /* printf("Parent has died - Authentication agent exiting.\n"); */
971 cleanup_handler(sig); /* safe */
972 }
973 mysignal(SIGALRM, check_parent_exists);
974 alarm(10);
975 errno = save_errno;
976 }
977
978 static void
979 usage(void)
980 {
981 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
982 __progname);
983 fprintf(stderr, "Options:\n");
984 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
985 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
986 fprintf(stderr, " -k Kill the current agent.\n");
987 fprintf(stderr, " -d Debug mode.\n");
988 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
989 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
990 exit(1);
991 }
992
993 int
994 main(int ac, char **av)
995 {
996 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
997 int sock, fd, ch;
998 u_int nalloc;
999 char *shell, *format, *pidstr, *agentsocket = NULL;
1000 fd_set *readsetp = NULL, *writesetp = NULL;
1001 struct sockaddr_un sunaddr;
1002 #ifdef HAVE_SETRLIMIT
1003 struct rlimit rlim;
1004 #endif
1005 int prev_mask;
1006 extern int optind;
1007 extern char *optarg;
1008 pid_t pid;
1009 char pidstrbuf[1 + 3 * sizeof pid];
1010
1011 /* drop */
1012 setegid(getgid());
1013 setgid(getgid());
1014
1015 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1016 /* Disable ptrace on Linux without sgid bit */
1017 prctl(PR_SET_DUMPABLE, 0);
1018 #endif
1019
1020 SSLeay_add_all_algorithms();
1021
1022 __progname = ssh_get_progname(av[0]);
1023 init_rng();
1024 seed_rng();
1025
1026 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1027 switch (ch) {
1028 case 'c':
1029 if (s_flag)
1030 usage();
1031 c_flag++;
1032 break;
1033 case 'k':
1034 k_flag++;
1035 break;
1036 case 's':
1037 if (c_flag)
1038 usage();
1039 s_flag++;
1040 break;
1041 case 'd':
1042 if (d_flag)
1043 usage();
1044 d_flag++;
1045 break;
1046 case 'a':
1047 agentsocket = optarg;
1048 break;
1049 case 't':
1050 if ((lifetime = convtime(optarg)) == -1) {
1051 fprintf(stderr, "Invalid lifetime\n");
1052 usage();
1053 }
1054 break;
1055 default:
1056 usage();
1057 }
1058 }
1059 ac -= optind;
1060 av += optind;
1061
1062 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1063 usage();
1064
1065 if (ac == 0 && !c_flag && !s_flag) {
1066 shell = getenv("SHELL");
1067 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1068 c_flag = 1;
1069 }
1070 if (k_flag) {
1071 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1072 if (pidstr == NULL) {
1073 fprintf(stderr, "%s not set, cannot kill agent\n",
1074 SSH_AGENTPID_ENV_NAME);
1075 exit(1);
1076 }
1077 pid = atoi(pidstr);
1078 if (pid < 1) {
1079 fprintf(stderr, "%s=\"%s\", which is not a good PID\n",
1080 SSH_AGENTPID_ENV_NAME, pidstr);
1081 exit(1);
1082 }
1083 if (kill(pid, SIGTERM) == -1) {
1084 perror("kill");
1085 exit(1);
1086 }
1087 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1088 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1089 printf(format, SSH_AGENTPID_ENV_NAME);
1090 printf("echo Agent pid %ld killed;\n", (long)pid);
1091 exit(0);
1092 }
1093 parent_pid = getpid();
1094
1095 if (agentsocket == NULL) {
1096 /* Create private directory for agent socket */
1097 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1098 if (mkdtemp(socket_dir) == NULL) {
1099 perror("mkdtemp: private socket dir");
1100 exit(1);
1101 }
1102 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1103 (long)parent_pid);
1104 } else {
1105 /* Try to use specified agent socket */
1106 socket_dir[0] = '\0';
1107 strlcpy(socket_name, agentsocket, sizeof socket_name);
1108 }
1109
1110 /*
1111 * Create socket early so it will exist before command gets run from
1112 * the parent.
1113 */
1114 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1115 if (sock < 0) {
1116 perror("socket");
1117 *socket_name = '\0'; /* Don't unlink any existing file */
1118 cleanup_exit(1);
1119 }
1120 memset(&sunaddr, 0, sizeof(sunaddr));
1121 sunaddr.sun_family = AF_UNIX;
1122 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1123 prev_mask = umask(0177);
1124 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
1125 perror("bind");
1126 *socket_name = '\0'; /* Don't unlink any existing file */
1127 umask(prev_mask);
1128 cleanup_exit(1);
1129 }
1130 umask(prev_mask);
1131 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1132 perror("listen");
1133 cleanup_exit(1);
1134 }
1135
1136 /*
1137 * Fork, and have the parent execute the command, if any, or present
1138 * the socket data. The child continues as the authentication agent.
1139 */
1140 if (d_flag) {
1141 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1142 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1143 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1144 SSH_AUTHSOCKET_ENV_NAME);
1145 printf("echo Agent pid %ld;\n", (long)parent_pid);
1146 goto skip;
1147 }
1148 pid = fork();
1149 if (pid == -1) {
1150 perror("fork");
1151 cleanup_exit(1);
1152 }
1153 if (pid != 0) { /* Parent - execute the given command. */
1154 close(sock);
1155 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1156 if (ac == 0) {
1157 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1158 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1159 SSH_AUTHSOCKET_ENV_NAME);
1160 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1161 SSH_AGENTPID_ENV_NAME);
1162 printf("echo Agent pid %ld;\n", (long)pid);
1163 exit(0);
1164 }
1165 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1166 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1167 perror("setenv");
1168 exit(1);
1169 }
1170 execvp(av[0], av);
1171 perror(av[0]);
1172 exit(1);
1173 }
1174 /* child */
1175 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1176
1177 if (setsid() == -1) {
1178 error("setsid: %s", strerror(errno));
1179 cleanup_exit(1);
1180 }
1181
1182 (void)chdir("/");
1183 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1184 /* XXX might close listen socket */
1185 (void)dup2(fd, STDIN_FILENO);
1186 (void)dup2(fd, STDOUT_FILENO);
1187 (void)dup2(fd, STDERR_FILENO);
1188 if (fd > 2)
1189 close(fd);
1190 }
1191
1192 #ifdef HAVE_SETRLIMIT
1193 /* deny core dumps, since memory contains unencrypted private keys */
1194 rlim.rlim_cur = rlim.rlim_max = 0;
1195 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1196 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1197 cleanup_exit(1);
1198 }
1199 #endif
1200
1201 skip:
1202 new_socket(AUTH_SOCKET, sock);
1203 if (ac > 0) {
1204 mysignal(SIGALRM, check_parent_exists);
1205 alarm(10);
1206 }
1207 idtab_init();
1208 if (!d_flag)
1209 signal(SIGINT, SIG_IGN);
1210 signal(SIGPIPE, SIG_IGN);
1211 signal(SIGHUP, cleanup_handler);
1212 signal(SIGTERM, cleanup_handler);
1213 nalloc = 0;
1214
1215 while (1) {
1216 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc);
1217 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) {
1218 if (errno == EINTR)
1219 continue;
1220 fatal("select: %s", strerror(errno));
1221 }
1222 after_select(readsetp, writesetp);
1223 }
1224 /* NOTREACHED */
1225 }
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