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Kernel part of bluetooth stack ported by Dmitry Komissaroff. Very much work
[dragonfly.git] / crypto / openssh-4 / ssh-agent.c
blobc3d5e5a757d9409a4e6289c8c43841ab44f2c6da
1 /* $OpenBSD: ssh-agent.c,v 1.155 2007/03/19 12:16:42 dtucker 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
55 #include <errno.h>
56 #include <fcntl.h>
57 #ifdef HAVE_PATHS_H
58 # include <paths.h>
59 #endif
60 #include <signal.h>
61 #include <stdarg.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <time.h>
65 #include <string.h>
66 #include <unistd.h>
67
68 #include "xmalloc.h"
69 #include "ssh.h"
70 #include "rsa.h"
71 #include "buffer.h"
72 #include "key.h"
73 #include "authfd.h"
74 #include "compat.h"
75 #include "log.h"
76 #include "misc.h"
77
78 #ifdef SMARTCARD
79 #include "scard.h"
80 #endif
81
82 #if defined(HAVE_SYS_PRCTL_H)
83 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
84 #endif
85
86 typedef enum {
87 AUTH_UNUSED,
88 AUTH_SOCKET,
89 AUTH_CONNECTION
90 } sock_type;
91
92 typedef struct {
93 int fd;
94 sock_type type;
95 Buffer input;
96 Buffer output;
97 Buffer request;
98 } SocketEntry;
99
100 u_int sockets_alloc = 0;
101 SocketEntry *sockets = NULL;
102
103 typedef struct identity {
104 TAILQ_ENTRY(identity) next;
105 Key *key;
106 char *comment;
107 u_int death;
108 u_int confirm;
109 } Identity;
110
111 typedef struct {
112 int nentries;
113 TAILQ_HEAD(idqueue, identity) idlist;
114 } Idtab;
115
116 /* private key table, one per protocol version */
117 Idtab idtable[3];
118
119 int max_fd = 0;
120
121 /* pid of shell == parent of agent */
122 pid_t parent_pid = -1;
123 u_int parent_alive_interval = 0;
124
125 /* pathname and directory for AUTH_SOCKET */
126 char socket_name[MAXPATHLEN];
127 char socket_dir[MAXPATHLEN];
128
129 /* locking */
130 int locked = 0;
131 char *lock_passwd = NULL;
132
133 extern char *__progname;
134
135 /* Default lifetime (0 == forever) */
136 static int lifetime = 0;
137
138 static void
139 close_socket(SocketEntry *e)
140 {
141 close(e->fd);
142 e->fd = -1;
143 e->type = AUTH_UNUSED;
144 buffer_free(&e->input);
145 buffer_free(&e->output);
146 buffer_free(&e->request);
147 }
148
149 static void
150 idtab_init(void)
151 {
152 int i;
153
154 for (i = 0; i <=2; i++) {
155 TAILQ_INIT(&idtable[i].idlist);
156 idtable[i].nentries = 0;
157 }
158 }
159
160 /* return private key table for requested protocol version */
161 static Idtab *
162 idtab_lookup(int version)
163 {
164 if (version < 1 || version > 2)
165 fatal("internal error, bad protocol version %d", version);
166 return &idtable[version];
167 }
168
169 static void
170 free_identity(Identity *id)
171 {
172 key_free(id->key);
173 xfree(id->comment);
174 xfree(id);
175 }
176
177 /* return matching private key for given public key */
178 static Identity *
179 lookup_identity(Key *key, int version)
180 {
181 Identity *id;
182
183 Idtab *tab = idtab_lookup(version);
184 TAILQ_FOREACH(id, &tab->idlist, next) {
185 if (key_equal(key, id->key))
186 return (id);
187 }
188 return (NULL);
189 }
190
191 /* Check confirmation of keysign request */
192 static int
193 confirm_key(Identity *id)
194 {
195 char *p;
196 int ret = -1;
197
198 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
199 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
200 id->comment, p))
201 ret = 0;
202 xfree(p);
203
204 return (ret);
205 }
206
207 /* send list of supported public keys to 'client' */
208 static void
209 process_request_identities(SocketEntry *e, int version)
210 {
211 Idtab *tab = idtab_lookup(version);
212 Identity *id;
213 Buffer msg;
214
215 buffer_init(&msg);
216 buffer_put_char(&msg, (version == 1) ?
217 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
218 buffer_put_int(&msg, tab->nentries);
219 TAILQ_FOREACH(id, &tab->idlist, next) {
220 if (id->key->type == KEY_RSA1) {
221 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
222 buffer_put_bignum(&msg, id->key->rsa->e);
223 buffer_put_bignum(&msg, id->key->rsa->n);
224 } else {
225 u_char *blob;
226 u_int blen;
227 key_to_blob(id->key, &blob, &blen);
228 buffer_put_string(&msg, blob, blen);
229 xfree(blob);
230 }
231 buffer_put_cstring(&msg, id->comment);
232 }
233 buffer_put_int(&e->output, buffer_len(&msg));
234 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
235 buffer_free(&msg);
236 }
237
238 /* ssh1 only */
239 static void
240 process_authentication_challenge1(SocketEntry *e)
241 {
242 u_char buf[32], mdbuf[16], session_id[16];
243 u_int response_type;
244 BIGNUM *challenge;
245 Identity *id;
246 int i, len;
247 Buffer msg;
248 MD5_CTX md;
249 Key *key;
250
251 buffer_init(&msg);
252 key = key_new(KEY_RSA1);
253 if ((challenge = BN_new()) == NULL)
254 fatal("process_authentication_challenge1: BN_new failed");
255
256 (void) buffer_get_int(&e->request); /* ignored */
257 buffer_get_bignum(&e->request, key->rsa->e);
258 buffer_get_bignum(&e->request, key->rsa->n);
259 buffer_get_bignum(&e->request, challenge);
260
261 /* Only protocol 1.1 is supported */
262 if (buffer_len(&e->request) == 0)
263 goto failure;
264 buffer_get(&e->request, session_id, 16);
265 response_type = buffer_get_int(&e->request);
266 if (response_type != 1)
267 goto failure;
268
269 id = lookup_identity(key, 1);
270 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
271 Key *private = id->key;
272 /* Decrypt the challenge using the private key. */
273 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
274 goto failure;
275
276 /* The response is MD5 of decrypted challenge plus session id. */
277 len = BN_num_bytes(challenge);
278 if (len <= 0 || len > 32) {
279 logit("process_authentication_challenge: bad challenge length %d", len);
280 goto failure;
281 }
282 memset(buf, 0, 32);
283 BN_bn2bin(challenge, buf + 32 - len);
284 MD5_Init(&md);
285 MD5_Update(&md, buf, 32);
286 MD5_Update(&md, session_id, 16);
287 MD5_Final(mdbuf, &md);
288
289 /* Send the response. */
290 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
291 for (i = 0; i < 16; i++)
292 buffer_put_char(&msg, mdbuf[i]);
293 goto send;
294 }
295
296 failure:
297 /* Unknown identity or protocol error. Send failure. */
298 buffer_put_char(&msg, SSH_AGENT_FAILURE);
299 send:
300 buffer_put_int(&e->output, buffer_len(&msg));
301 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
302 key_free(key);
303 BN_clear_free(challenge);
304 buffer_free(&msg);
305 }
306
307 /* ssh2 only */
308 static void
309 process_sign_request2(SocketEntry *e)
310 {
311 u_char *blob, *data, *signature = NULL;
312 u_int blen, dlen, slen = 0;
313 extern int datafellows;
314 int ok = -1, flags;
315 Buffer msg;
316 Key *key;
317
318 datafellows = 0;
319
320 blob = buffer_get_string(&e->request, &blen);
321 data = buffer_get_string(&e->request, &dlen);
322
323 flags = buffer_get_int(&e->request);
324 if (flags & SSH_AGENT_OLD_SIGNATURE)
325 datafellows = SSH_BUG_SIGBLOB;
326
327 key = key_from_blob(blob, blen);
328 if (key != NULL) {
329 Identity *id = lookup_identity(key, 2);
330 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
331 ok = key_sign(id->key, &signature, &slen, data, dlen);
332 key_free(key);
333 }
334 buffer_init(&msg);
335 if (ok == 0) {
336 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
337 buffer_put_string(&msg, signature, slen);
338 } else {
339 buffer_put_char(&msg, SSH_AGENT_FAILURE);
340 }
341 buffer_put_int(&e->output, buffer_len(&msg));
342 buffer_append(&e->output, buffer_ptr(&msg),
343 buffer_len(&msg));
344 buffer_free(&msg);
345 xfree(data);
346 xfree(blob);
347 if (signature != NULL)
348 xfree(signature);
349 }
350
351 /* shared */
352 static void
353 process_remove_identity(SocketEntry *e, int version)
354 {
355 u_int blen, bits;
356 int success = 0;
357 Key *key = NULL;
358 u_char *blob;
359
360 switch (version) {
361 case 1:
362 key = key_new(KEY_RSA1);
363 bits = buffer_get_int(&e->request);
364 buffer_get_bignum(&e->request, key->rsa->e);
365 buffer_get_bignum(&e->request, key->rsa->n);
366
367 if (bits != key_size(key))
368 logit("Warning: identity keysize mismatch: actual %u, announced %u",
369 key_size(key), bits);
370 break;
371 case 2:
372 blob = buffer_get_string(&e->request, &blen);
373 key = key_from_blob(blob, blen);
374 xfree(blob);
375 break;
376 }
377 if (key != NULL) {
378 Identity *id = lookup_identity(key, version);
379 if (id != NULL) {
380 /*
381 * We have this key. Free the old key. Since we
382 * don't want to leave empty slots in the middle of
383 * the array, we actually free the key there and move
384 * all the entries between the empty slot and the end
385 * of the array.
386 */
387 Idtab *tab = idtab_lookup(version);
388 if (tab->nentries < 1)
389 fatal("process_remove_identity: "
390 "internal error: tab->nentries %d",
391 tab->nentries);
392 TAILQ_REMOVE(&tab->idlist, id, next);
393 free_identity(id);
394 tab->nentries--;
395 success = 1;
396 }
397 key_free(key);
398 }
399 buffer_put_int(&e->output, 1);
400 buffer_put_char(&e->output,
401 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
402 }
403
404 static void
405 process_remove_all_identities(SocketEntry *e, int version)
406 {
407 Idtab *tab = idtab_lookup(version);
408 Identity *id;
409
410 /* Loop over all identities and clear the keys. */
411 for (id = TAILQ_FIRST(&tab->idlist); id;
412 id = TAILQ_FIRST(&tab->idlist)) {
413 TAILQ_REMOVE(&tab->idlist, id, next);
414 free_identity(id);
415 }
416
417 /* Mark that there are no identities. */
418 tab->nentries = 0;
419
420 /* Send success. */
421 buffer_put_int(&e->output, 1);
422 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
423 }
424
425 /* removes expired keys and returns number of seconds until the next expiry */
426 static u_int
427 reaper(void)
428 {
429 u_int deadline = 0, now = time(NULL);
430 Identity *id, *nxt;
431 int version;
432 Idtab *tab;
433
434 for (version = 1; version < 3; version++) {
435 tab = idtab_lookup(version);
436 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
437 nxt = TAILQ_NEXT(id, next);
438 if (id->death == 0)
439 continue;
440 if (now >= id->death) {
441 debug("expiring key '%s'", id->comment);
442 TAILQ_REMOVE(&tab->idlist, id, next);
443 free_identity(id);
444 tab->nentries--;
445 } else
446 deadline = (deadline == 0) ? id->death :
447 MIN(deadline, id->death);
448 }
449 }
450 if (deadline == 0 || deadline <= now)
451 return 0;
452 else
453 return (deadline - now);
454 }
455
456 static void
457 process_add_identity(SocketEntry *e, int version)
458 {
459 Idtab *tab = idtab_lookup(version);
460 int type, success = 0, death = 0, confirm = 0;
461 char *type_name, *comment;
462 Key *k = NULL;
463
464 switch (version) {
465 case 1:
466 k = key_new_private(KEY_RSA1);
467 (void) buffer_get_int(&e->request); /* ignored */
468 buffer_get_bignum(&e->request, k->rsa->n);
469 buffer_get_bignum(&e->request, k->rsa->e);
470 buffer_get_bignum(&e->request, k->rsa->d);
471 buffer_get_bignum(&e->request, k->rsa->iqmp);
472
473 /* SSH and SSL have p and q swapped */
474 buffer_get_bignum(&e->request, k->rsa->q); /* p */
475 buffer_get_bignum(&e->request, k->rsa->p); /* q */
476
477 /* Generate additional parameters */
478 rsa_generate_additional_parameters(k->rsa);
479 break;
480 case 2:
481 type_name = buffer_get_string(&e->request, NULL);
482 type = key_type_from_name(type_name);
483 xfree(type_name);
484 switch (type) {
485 case KEY_DSA:
486 k = key_new_private(type);
487 buffer_get_bignum2(&e->request, k->dsa->p);
488 buffer_get_bignum2(&e->request, k->dsa->q);
489 buffer_get_bignum2(&e->request, k->dsa->g);
490 buffer_get_bignum2(&e->request, k->dsa->pub_key);
491 buffer_get_bignum2(&e->request, k->dsa->priv_key);
492 break;
493 case KEY_RSA:
494 k = key_new_private(type);
495 buffer_get_bignum2(&e->request, k->rsa->n);
496 buffer_get_bignum2(&e->request, k->rsa->e);
497 buffer_get_bignum2(&e->request, k->rsa->d);
498 buffer_get_bignum2(&e->request, k->rsa->iqmp);
499 buffer_get_bignum2(&e->request, k->rsa->p);
500 buffer_get_bignum2(&e->request, k->rsa->q);
501
502 /* Generate additional parameters */
503 rsa_generate_additional_parameters(k->rsa);
504 break;
505 default:
506 buffer_clear(&e->request);
507 goto send;
508 }
509 break;
510 }
511 /* enable blinding */
512 switch (k->type) {
513 case KEY_RSA:
514 case KEY_RSA1:
515 if (RSA_blinding_on(k->rsa, NULL) != 1) {
516 error("process_add_identity: RSA_blinding_on failed");
517 key_free(k);
518 goto send;
519 }
520 break;
521 }
522 comment = buffer_get_string(&e->request, NULL);
523 if (k == NULL) {
524 xfree(comment);
525 goto send;
526 }
527 success = 1;
528 while (buffer_len(&e->request)) {
529 switch (buffer_get_char(&e->request)) {
530 case SSH_AGENT_CONSTRAIN_LIFETIME:
531 death = time(NULL) + buffer_get_int(&e->request);
532 break;
533 case SSH_AGENT_CONSTRAIN_CONFIRM:
534 confirm = 1;
535 break;
536 default:
537 break;
538 }
539 }
540 if (lifetime && !death)
541 death = time(NULL) + lifetime;
542 if (lookup_identity(k, version) == NULL) {
543 Identity *id = xmalloc(sizeof(Identity));
544 id->key = k;
545 id->comment = comment;
546 id->death = death;
547 id->confirm = confirm;
548 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
549 /* Increment the number of identities. */
550 tab->nentries++;
551 } else {
552 key_free(k);
553 xfree(comment);
554 }
555 send:
556 buffer_put_int(&e->output, 1);
557 buffer_put_char(&e->output,
558 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
559 }
560
561 /* XXX todo: encrypt sensitive data with passphrase */
562 static void
563 process_lock_agent(SocketEntry *e, int lock)
564 {
565 int success = 0;
566 char *passwd;
567
568 passwd = buffer_get_string(&e->request, NULL);
569 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
570 locked = 0;
571 memset(lock_passwd, 0, strlen(lock_passwd));
572 xfree(lock_passwd);
573 lock_passwd = NULL;
574 success = 1;
575 } else if (!locked && lock) {
576 locked = 1;
577 lock_passwd = xstrdup(passwd);
578 success = 1;
579 }
580 memset(passwd, 0, strlen(passwd));
581 xfree(passwd);
582
583 buffer_put_int(&e->output, 1);
584 buffer_put_char(&e->output,
585 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
586 }
587
588 static void
589 no_identities(SocketEntry *e, u_int type)
590 {
591 Buffer msg;
592
593 buffer_init(&msg);
594 buffer_put_char(&msg,
595 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
596 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
597 buffer_put_int(&msg, 0);
598 buffer_put_int(&e->output, buffer_len(&msg));
599 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
600 buffer_free(&msg);
601 }
602
603 #ifdef SMARTCARD
604 static void
605 process_add_smartcard_key (SocketEntry *e)
606 {
607 char *sc_reader_id = NULL, *pin;
608 int i, version, success = 0, death = 0, confirm = 0;
609 Key **keys, *k;
610 Identity *id;
611 Idtab *tab;
612
613 sc_reader_id = buffer_get_string(&e->request, NULL);
614 pin = buffer_get_string(&e->request, NULL);
615
616 while (buffer_len(&e->request)) {
617 switch (buffer_get_char(&e->request)) {
618 case SSH_AGENT_CONSTRAIN_LIFETIME:
619 death = time(NULL) + buffer_get_int(&e->request);
620 break;
621 case SSH_AGENT_CONSTRAIN_CONFIRM:
622 confirm = 1;
623 break;
624 default:
625 break;
626 }
627 }
628 if (lifetime && !death)
629 death = time(NULL) + lifetime;
630
631 keys = sc_get_keys(sc_reader_id, pin);
632 xfree(sc_reader_id);
633 xfree(pin);
634
635 if (keys == NULL || keys[0] == NULL) {
636 error("sc_get_keys failed");
637 goto send;
638 }
639 for (i = 0; keys[i] != NULL; i++) {
640 k = keys[i];
641 version = k->type == KEY_RSA1 ? 1 : 2;
642 tab = idtab_lookup(version);
643 if (lookup_identity(k, version) == NULL) {
644 id = xmalloc(sizeof(Identity));
645 id->key = k;
646 id->comment = sc_get_key_label(k);
647 id->death = death;
648 id->confirm = confirm;
649 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
650 tab->nentries++;
651 success = 1;
652 } else {
653 key_free(k);
654 }
655 keys[i] = NULL;
656 }
657 xfree(keys);
658 send:
659 buffer_put_int(&e->output, 1);
660 buffer_put_char(&e->output,
661 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
662 }
663
664 static void
665 process_remove_smartcard_key(SocketEntry *e)
666 {
667 char *sc_reader_id = NULL, *pin;
668 int i, version, success = 0;
669 Key **keys, *k = NULL;
670 Identity *id;
671 Idtab *tab;
672
673 sc_reader_id = buffer_get_string(&e->request, NULL);
674 pin = buffer_get_string(&e->request, NULL);
675 keys = sc_get_keys(sc_reader_id, pin);
676 xfree(sc_reader_id);
677 xfree(pin);
678
679 if (keys == NULL || keys[0] == NULL) {
680 error("sc_get_keys failed");
681 goto send;
682 }
683 for (i = 0; keys[i] != NULL; i++) {
684 k = keys[i];
685 version = k->type == KEY_RSA1 ? 1 : 2;
686 if ((id = lookup_identity(k, version)) != NULL) {
687 tab = idtab_lookup(version);
688 TAILQ_REMOVE(&tab->idlist, id, next);
689 tab->nentries--;
690 free_identity(id);
691 success = 1;
692 }
693 key_free(k);
694 keys[i] = NULL;
695 }
696 xfree(keys);
697 send:
698 buffer_put_int(&e->output, 1);
699 buffer_put_char(&e->output,
700 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
701 }
702 #endif /* SMARTCARD */
703
704 /* dispatch incoming messages */
705
706 static void
707 process_message(SocketEntry *e)
708 {
709 u_int msg_len, type;
710 u_char *cp;
711
712 if (buffer_len(&e->input) < 5)
713 return; /* Incomplete message. */
714 cp = buffer_ptr(&e->input);
715 msg_len = get_u32(cp);
716 if (msg_len > 256 * 1024) {
717 close_socket(e);
718 return;
719 }
720 if (buffer_len(&e->input) < msg_len + 4)
721 return;
722
723 /* move the current input to e->request */
724 buffer_consume(&e->input, 4);
725 buffer_clear(&e->request);
726 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
727 buffer_consume(&e->input, msg_len);
728 type = buffer_get_char(&e->request);
729
730 /* check wheter agent is locked */
731 if (locked && type != SSH_AGENTC_UNLOCK) {
732 buffer_clear(&e->request);
733 switch (type) {
734 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
735 case SSH2_AGENTC_REQUEST_IDENTITIES:
736 /* send empty lists */
737 no_identities(e, type);
738 break;
739 default:
740 /* send a fail message for all other request types */
741 buffer_put_int(&e->output, 1);
742 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
743 }
744 return;
745 }
746
747 debug("type %d", type);
748 switch (type) {
749 case SSH_AGENTC_LOCK:
750 case SSH_AGENTC_UNLOCK:
751 process_lock_agent(e, type == SSH_AGENTC_LOCK);
752 break;
753 /* ssh1 */
754 case SSH_AGENTC_RSA_CHALLENGE:
755 process_authentication_challenge1(e);
756 break;
757 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
758 process_request_identities(e, 1);
759 break;
760 case SSH_AGENTC_ADD_RSA_IDENTITY:
761 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
762 process_add_identity(e, 1);
763 break;
764 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
765 process_remove_identity(e, 1);
766 break;
767 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
768 process_remove_all_identities(e, 1);
769 break;
770 /* ssh2 */
771 case SSH2_AGENTC_SIGN_REQUEST:
772 process_sign_request2(e);
773 break;
774 case SSH2_AGENTC_REQUEST_IDENTITIES:
775 process_request_identities(e, 2);
776 break;
777 case SSH2_AGENTC_ADD_IDENTITY:
778 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
779 process_add_identity(e, 2);
780 break;
781 case SSH2_AGENTC_REMOVE_IDENTITY:
782 process_remove_identity(e, 2);
783 break;
784 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
785 process_remove_all_identities(e, 2);
786 break;
787 #ifdef SMARTCARD
788 case SSH_AGENTC_ADD_SMARTCARD_KEY:
789 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
790 process_add_smartcard_key(e);
791 break;
792 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
793 process_remove_smartcard_key(e);
794 break;
795 #endif /* SMARTCARD */
796 default:
797 /* Unknown message. Respond with failure. */
798 error("Unknown message %d", type);
799 buffer_clear(&e->request);
800 buffer_put_int(&e->output, 1);
801 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
802 break;
803 }
804 }
805
806 static void
807 new_socket(sock_type type, int fd)
808 {
809 u_int i, old_alloc, new_alloc;
810
811 set_nonblock(fd);
812
813 if (fd > max_fd)
814 max_fd = fd;
815
816 for (i = 0; i < sockets_alloc; i++)
817 if (sockets[i].type == AUTH_UNUSED) {
818 sockets[i].fd = fd;
819 buffer_init(&sockets[i].input);
820 buffer_init(&sockets[i].output);
821 buffer_init(&sockets[i].request);
822 sockets[i].type = type;
823 return;
824 }
825 old_alloc = sockets_alloc;
826 new_alloc = sockets_alloc + 10;
827 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
828 for (i = old_alloc; i < new_alloc; i++)
829 sockets[i].type = AUTH_UNUSED;
830 sockets_alloc = new_alloc;
831 sockets[old_alloc].fd = fd;
832 buffer_init(&sockets[old_alloc].input);
833 buffer_init(&sockets[old_alloc].output);
834 buffer_init(&sockets[old_alloc].request);
835 sockets[old_alloc].type = type;
836 }
837
838 static int
839 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
840 struct timeval **tvpp)
841 {
842 u_int i, sz, deadline;
843 int n = 0;
844 static struct timeval tv;
845
846 for (i = 0; i < sockets_alloc; i++) {
847 switch (sockets[i].type) {
848 case AUTH_SOCKET:
849 case AUTH_CONNECTION:
850 n = MAX(n, sockets[i].fd);
851 break;
852 case AUTH_UNUSED:
853 break;
854 default:
855 fatal("Unknown socket type %d", sockets[i].type);
856 break;
857 }
858 }
859
860 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
861 if (*fdrp == NULL || sz > *nallocp) {
862 if (*fdrp)
863 xfree(*fdrp);
864 if (*fdwp)
865 xfree(*fdwp);
866 *fdrp = xmalloc(sz);
867 *fdwp = xmalloc(sz);
868 *nallocp = sz;
869 }
870 if (n < *fdl)
871 debug("XXX shrink: %d < %d", n, *fdl);
872 *fdl = n;
873 memset(*fdrp, 0, sz);
874 memset(*fdwp, 0, sz);
875
876 for (i = 0; i < sockets_alloc; i++) {
877 switch (sockets[i].type) {
878 case AUTH_SOCKET:
879 case AUTH_CONNECTION:
880 FD_SET(sockets[i].fd, *fdrp);
881 if (buffer_len(&sockets[i].output) > 0)
882 FD_SET(sockets[i].fd, *fdwp);
883 break;
884 default:
885 break;
886 }
887 }
888 deadline = reaper();
889 if (parent_alive_interval != 0)
890 deadline = (deadline == 0) ? parent_alive_interval :
891 MIN(deadline, parent_alive_interval);
892 if (deadline == 0) {
893 *tvpp = NULL;
894 } else {
895 tv.tv_sec = deadline;
896 tv.tv_usec = 0;
897 *tvpp = &tv;
898 }
899 return (1);
900 }
901
902 static void
903 after_select(fd_set *readset, fd_set *writeset)
904 {
905 struct sockaddr_un sunaddr;
906 socklen_t slen;
907 char buf[1024];
908 int len, sock;
909 u_int i;
910 uid_t euid;
911 gid_t egid;
912
913 for (i = 0; i < sockets_alloc; i++)
914 switch (sockets[i].type) {
915 case AUTH_UNUSED:
916 break;
917 case AUTH_SOCKET:
918 if (FD_ISSET(sockets[i].fd, readset)) {
919 slen = sizeof(sunaddr);
920 sock = accept(sockets[i].fd,
921 (struct sockaddr *)&sunaddr, &slen);
922 if (sock < 0) {
923 error("accept from AUTH_SOCKET: %s",
924 strerror(errno));
925 break;
926 }
927 if (getpeereid(sock, &euid, &egid) < 0) {
928 error("getpeereid %d failed: %s",
929 sock, strerror(errno));
930 close(sock);
931 break;
932 }
933 if ((euid != 0) && (getuid() != euid)) {
934 error("uid mismatch: "
935 "peer euid %u != uid %u",
936 (u_int) euid, (u_int) getuid());
937 close(sock);
938 break;
939 }
940 new_socket(AUTH_CONNECTION, sock);
941 }
942 break;
943 case AUTH_CONNECTION:
944 if (buffer_len(&sockets[i].output) > 0 &&
945 FD_ISSET(sockets[i].fd, writeset)) {
946 do {
947 len = write(sockets[i].fd,
948 buffer_ptr(&sockets[i].output),
949 buffer_len(&sockets[i].output));
950 if (len == -1 && (errno == EAGAIN ||
951 errno == EINTR))
952 continue;
953 break;
954 } while (1);
955 if (len <= 0) {
956 close_socket(&sockets[i]);
957 break;
958 }
959 buffer_consume(&sockets[i].output, len);
960 }
961 if (FD_ISSET(sockets[i].fd, readset)) {
962 do {
963 len = read(sockets[i].fd, buf, sizeof(buf));
964 if (len == -1 && (errno == EAGAIN ||
965 errno == EINTR))
966 continue;
967 break;
968 } while (1);
969 if (len <= 0) {
970 close_socket(&sockets[i]);
971 break;
972 }
973 buffer_append(&sockets[i].input, buf, len);
974 process_message(&sockets[i]);
975 }
976 break;
977 default:
978 fatal("Unknown type %d", sockets[i].type);
979 }
980 }
981
982 static void
983 cleanup_socket(void)
984 {
985 if (socket_name[0])
986 unlink(socket_name);
987 if (socket_dir[0])
988 rmdir(socket_dir);
989 }
990
991 void
992 cleanup_exit(int i)
993 {
994 cleanup_socket();
995 _exit(i);
996 }
997
998 /*ARGSUSED*/
999 static void
1000 cleanup_handler(int sig)
1001 {
1002 cleanup_socket();
1003 _exit(2);
1004 }
1005
1006 static void
1007 check_parent_exists(void)
1008 {
1009 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1010 /* printf("Parent has died - Authentication agent exiting.\n"); */
1011 cleanup_socket();
1012 _exit(2);
1013 }
1014 }
1015
1016 static void
1017 usage(void)
1018 {
1019 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
1020 __progname);
1021 fprintf(stderr, "Options:\n");
1022 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1023 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1024 fprintf(stderr, " -k Kill the current agent.\n");
1025 fprintf(stderr, " -d Debug mode.\n");
1026 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1027 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1028 exit(1);
1029 }
1030
1031 int
1032 main(int ac, char **av)
1033 {
1034 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1035 int sock, fd, ch, result, saved_errno;
1036 u_int nalloc;
1037 char *shell, *format, *pidstr, *agentsocket = NULL;
1038 fd_set *readsetp = NULL, *writesetp = NULL;
1039 struct sockaddr_un sunaddr;
1040 #ifdef HAVE_SETRLIMIT
1041 struct rlimit rlim;
1042 #endif
1043 int prev_mask;
1044 extern int optind;
1045 extern char *optarg;
1046 pid_t pid;
1047 char pidstrbuf[1 + 3 * sizeof pid];
1048 struct timeval *tvp = NULL;
1049
1050 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1051 sanitise_stdfd();
1052
1053 /* drop */
1054 setegid(getgid());
1055 setgid(getgid());
1056
1057 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1058 /* Disable ptrace on Linux without sgid bit */
1059 prctl(PR_SET_DUMPABLE, 0);
1060 #endif
1061
1062 SSLeay_add_all_algorithms();
1063
1064 __progname = ssh_get_progname(av[0]);
1065 init_rng();
1066 seed_rng();
1067
1068 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1069 switch (ch) {
1070 case 'c':
1071 if (s_flag)
1072 usage();
1073 c_flag++;
1074 break;
1075 case 'k':
1076 k_flag++;
1077 break;
1078 case 's':
1079 if (c_flag)
1080 usage();
1081 s_flag++;
1082 break;
1083 case 'd':
1084 if (d_flag)
1085 usage();
1086 d_flag++;
1087 break;
1088 case 'a':
1089 agentsocket = optarg;
1090 break;
1091 case 't':
1092 if ((lifetime = convtime(optarg)) == -1) {
1093 fprintf(stderr, "Invalid lifetime\n");
1094 usage();
1095 }
1096 break;
1097 default:
1098 usage();
1099 }
1100 }
1101 ac -= optind;
1102 av += optind;
1103
1104 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1105 usage();
1106
1107 if (ac == 0 && !c_flag && !s_flag) {
1108 shell = getenv("SHELL");
1109 if (shell != NULL &&
1110 strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1111 c_flag = 1;
1112 }
1113 if (k_flag) {
1114 const char *errstr = NULL;
1115
1116 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1117 if (pidstr == NULL) {
1118 fprintf(stderr, "%s not set, cannot kill agent\n",
1119 SSH_AGENTPID_ENV_NAME);
1120 exit(1);
1121 }
1122 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1123 if (errstr) {
1124 fprintf(stderr,
1125 "%s=\"%s\", which is not a good PID: %s\n",
1126 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1127 exit(1);
1128 }
1129 if (kill(pid, SIGTERM) == -1) {
1130 perror("kill");
1131 exit(1);
1132 }
1133 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1134 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1135 printf(format, SSH_AGENTPID_ENV_NAME);
1136 printf("echo Agent pid %ld killed;\n", (long)pid);
1137 exit(0);
1138 }
1139 parent_pid = getpid();
1140
1141 if (agentsocket == NULL) {
1142 /* Create private directory for agent socket */
1143 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1144 if (mkdtemp(socket_dir) == NULL) {
1145 perror("mkdtemp: private socket dir");
1146 exit(1);
1147 }
1148 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1149 (long)parent_pid);
1150 } else {
1151 /* Try to use specified agent socket */
1152 socket_dir[0] = '\0';
1153 strlcpy(socket_name, agentsocket, sizeof socket_name);
1154 }
1155
1156 /*
1157 * Create socket early so it will exist before command gets run from
1158 * the parent.
1159 */
1160 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1161 if (sock < 0) {
1162 perror("socket");
1163 *socket_name = '\0'; /* Don't unlink any existing file */
1164 cleanup_exit(1);
1165 }
1166 memset(&sunaddr, 0, sizeof(sunaddr));
1167 sunaddr.sun_family = AF_UNIX;
1168 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1169 prev_mask = umask(0177);
1170 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1171 perror("bind");
1172 *socket_name = '\0'; /* Don't unlink any existing file */
1173 umask(prev_mask);
1174 cleanup_exit(1);
1175 }
1176 umask(prev_mask);
1177 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1178 perror("listen");
1179 cleanup_exit(1);
1180 }
1181
1182 /*
1183 * Fork, and have the parent execute the command, if any, or present
1184 * the socket data. The child continues as the authentication agent.
1185 */
1186 if (d_flag) {
1187 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1188 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1189 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1190 SSH_AUTHSOCKET_ENV_NAME);
1191 printf("echo Agent pid %ld;\n", (long)parent_pid);
1192 goto skip;
1193 }
1194 pid = fork();
1195 if (pid == -1) {
1196 perror("fork");
1197 cleanup_exit(1);
1198 }
1199 if (pid != 0) { /* Parent - execute the given command. */
1200 close(sock);
1201 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1202 if (ac == 0) {
1203 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1204 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1205 SSH_AUTHSOCKET_ENV_NAME);
1206 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1207 SSH_AGENTPID_ENV_NAME);
1208 printf("echo Agent pid %ld;\n", (long)pid);
1209 exit(0);
1210 }
1211 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1212 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1213 perror("setenv");
1214 exit(1);
1215 }
1216 execvp(av[0], av);
1217 perror(av[0]);
1218 exit(1);
1219 }
1220 /* child */
1221 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1222
1223 if (setsid() == -1) {
1224 error("setsid: %s", strerror(errno));
1225 cleanup_exit(1);
1226 }
1227
1228 (void)chdir("/");
1229 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1230 /* XXX might close listen socket */
1231 (void)dup2(fd, STDIN_FILENO);
1232 (void)dup2(fd, STDOUT_FILENO);
1233 (void)dup2(fd, STDERR_FILENO);
1234 if (fd > 2)
1235 close(fd);
1236 }
1237
1238 #ifdef HAVE_SETRLIMIT
1239 /* deny core dumps, since memory contains unencrypted private keys */
1240 rlim.rlim_cur = rlim.rlim_max = 0;
1241 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1242 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1243 cleanup_exit(1);
1244 }
1245 #endif
1246
1247 skip:
1248 new_socket(AUTH_SOCKET, sock);
1249 if (ac > 0)
1250 parent_alive_interval = 10;
1251 idtab_init();
1252 if (!d_flag)
1253 signal(SIGINT, SIG_IGN);
1254 signal(SIGPIPE, SIG_IGN);
1255 signal(SIGHUP, cleanup_handler);
1256 signal(SIGTERM, cleanup_handler);
1257 nalloc = 0;
1258
1259 while (1) {
1260 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1261 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1262 saved_errno = errno;
1263 if (parent_alive_interval != 0)
1264 check_parent_exists();
1265 (void) reaper(); /* remove expired keys */
1266 if (result < 0) {
1267 if (saved_errno == EINTR)
1268 continue;
1269 fatal("select: %s", strerror(saved_errno));
1270 } else if (result > 0)
1271 after_select(readsetp, writesetp);
1272 }
1273 /* NOTREACHED */
1274 }
DragonFly BSD