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MFC: Make apps using '#define _POSIX_C_SOURCE' compile.
[dragonfly.git] / crypto / openssh-5 / ssh-agent.c
blobbbfa53da00801edc165d70c6f6d239c9f0d9cffb
1 /* $OpenBSD: ssh-agent.c,v 1.157 2007/09/25 23:48:57 canacar 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 SMARTCARD
80 #include "scard.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 u_int death;
109 u_int confirm;
110 } Identity;
111
112 typedef struct {
113 int nentries;
114 TAILQ_HEAD(idqueue, identity) idlist;
115 } Idtab;
116
117 /* private key table, one per protocol version */
118 Idtab idtable[3];
119
120 int max_fd = 0;
121
122 /* pid of shell == parent of agent */
123 pid_t parent_pid = -1;
124 u_int parent_alive_interval = 0;
125
126 /* pathname and directory for AUTH_SOCKET */
127 char socket_name[MAXPATHLEN];
128 char socket_dir[MAXPATHLEN];
129
130 /* locking */
131 int locked = 0;
132 char *lock_passwd = NULL;
133
134 extern char *__progname;
135
136 /* Default lifetime (0 == forever) */
137 static int lifetime = 0;
138
139 static void
140 close_socket(SocketEntry *e)
141 {
142 close(e->fd);
143 e->fd = -1;
144 e->type = AUTH_UNUSED;
145 buffer_free(&e->input);
146 buffer_free(&e->output);
147 buffer_free(&e->request);
148 }
149
150 static void
151 idtab_init(void)
152 {
153 int i;
154
155 for (i = 0; i <=2; i++) {
156 TAILQ_INIT(&idtable[i].idlist);
157 idtable[i].nentries = 0;
158 }
159 }
160
161 /* return private key table for requested protocol version */
162 static Idtab *
163 idtab_lookup(int version)
164 {
165 if (version < 1 || version > 2)
166 fatal("internal error, bad protocol version %d", version);
167 return &idtable[version];
168 }
169
170 static void
171 free_identity(Identity *id)
172 {
173 key_free(id->key);
174 xfree(id->comment);
175 xfree(id);
176 }
177
178 /* return matching private key for given public key */
179 static Identity *
180 lookup_identity(Key *key, int version)
181 {
182 Identity *id;
183
184 Idtab *tab = idtab_lookup(version);
185 TAILQ_FOREACH(id, &tab->idlist, next) {
186 if (key_equal(key, id->key))
187 return (id);
188 }
189 return (NULL);
190 }
191
192 /* Check confirmation of keysign request */
193 static int
194 confirm_key(Identity *id)
195 {
196 char *p;
197 int ret = -1;
198
199 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
200 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
201 id->comment, p))
202 ret = 0;
203 xfree(p);
204
205 return (ret);
206 }
207
208 /* send list of supported public keys to 'client' */
209 static void
210 process_request_identities(SocketEntry *e, int version)
211 {
212 Idtab *tab = idtab_lookup(version);
213 Identity *id;
214 Buffer msg;
215
216 buffer_init(&msg);
217 buffer_put_char(&msg, (version == 1) ?
218 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
219 buffer_put_int(&msg, tab->nentries);
220 TAILQ_FOREACH(id, &tab->idlist, next) {
221 if (id->key->type == KEY_RSA1) {
222 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
223 buffer_put_bignum(&msg, id->key->rsa->e);
224 buffer_put_bignum(&msg, id->key->rsa->n);
225 } else {
226 u_char *blob;
227 u_int blen;
228 key_to_blob(id->key, &blob, &blen);
229 buffer_put_string(&msg, blob, blen);
230 xfree(blob);
231 }
232 buffer_put_cstring(&msg, id->comment);
233 }
234 buffer_put_int(&e->output, buffer_len(&msg));
235 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
236 buffer_free(&msg);
237 }
238
239 /* ssh1 only */
240 static void
241 process_authentication_challenge1(SocketEntry *e)
242 {
243 u_char buf[32], mdbuf[16], session_id[16];
244 u_int response_type;
245 BIGNUM *challenge;
246 Identity *id;
247 int i, len;
248 Buffer msg;
249 MD5_CTX md;
250 Key *key;
251
252 buffer_init(&msg);
253 key = key_new(KEY_RSA1);
254 if ((challenge = BN_new()) == NULL)
255 fatal("process_authentication_challenge1: BN_new failed");
256
257 (void) buffer_get_int(&e->request); /* ignored */
258 buffer_get_bignum(&e->request, key->rsa->e);
259 buffer_get_bignum(&e->request, key->rsa->n);
260 buffer_get_bignum(&e->request, challenge);
261
262 /* Only protocol 1.1 is supported */
263 if (buffer_len(&e->request) == 0)
264 goto failure;
265 buffer_get(&e->request, session_id, 16);
266 response_type = buffer_get_int(&e->request);
267 if (response_type != 1)
268 goto failure;
269
270 id = lookup_identity(key, 1);
271 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
272 Key *private = id->key;
273 /* Decrypt the challenge using the private key. */
274 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
275 goto failure;
276
277 /* The response is MD5 of decrypted challenge plus session id. */
278 len = BN_num_bytes(challenge);
279 if (len <= 0 || len > 32) {
280 logit("process_authentication_challenge: bad challenge length %d", len);
281 goto failure;
282 }
283 memset(buf, 0, 32);
284 BN_bn2bin(challenge, buf + 32 - len);
285 MD5_Init(&md);
286 MD5_Update(&md, buf, 32);
287 MD5_Update(&md, session_id, 16);
288 MD5_Final(mdbuf, &md);
289
290 /* Send the response. */
291 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
292 for (i = 0; i < 16; i++)
293 buffer_put_char(&msg, mdbuf[i]);
294 goto send;
295 }
296
297 failure:
298 /* Unknown identity or protocol error. Send failure. */
299 buffer_put_char(&msg, SSH_AGENT_FAILURE);
300 send:
301 buffer_put_int(&e->output, buffer_len(&msg));
302 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
303 key_free(key);
304 BN_clear_free(challenge);
305 buffer_free(&msg);
306 }
307
308 /* ssh2 only */
309 static void
310 process_sign_request2(SocketEntry *e)
311 {
312 u_char *blob, *data, *signature = NULL;
313 u_int blen, dlen, slen = 0;
314 extern int datafellows;
315 int ok = -1, flags;
316 Buffer msg;
317 Key *key;
318
319 datafellows = 0;
320
321 blob = buffer_get_string(&e->request, &blen);
322 data = buffer_get_string(&e->request, &dlen);
323
324 flags = buffer_get_int(&e->request);
325 if (flags & SSH_AGENT_OLD_SIGNATURE)
326 datafellows = SSH_BUG_SIGBLOB;
327
328 key = key_from_blob(blob, blen);
329 if (key != NULL) {
330 Identity *id = lookup_identity(key, 2);
331 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
332 ok = key_sign(id->key, &signature, &slen, data, dlen);
333 key_free(key);
334 }
335 buffer_init(&msg);
336 if (ok == 0) {
337 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
338 buffer_put_string(&msg, signature, slen);
339 } else {
340 buffer_put_char(&msg, SSH_AGENT_FAILURE);
341 }
342 buffer_put_int(&e->output, buffer_len(&msg));
343 buffer_append(&e->output, buffer_ptr(&msg),
344 buffer_len(&msg));
345 buffer_free(&msg);
346 xfree(data);
347 xfree(blob);
348 if (signature != NULL)
349 xfree(signature);
350 }
351
352 /* shared */
353 static void
354 process_remove_identity(SocketEntry *e, int version)
355 {
356 u_int blen, bits;
357 int success = 0;
358 Key *key = NULL;
359 u_char *blob;
360
361 switch (version) {
362 case 1:
363 key = key_new(KEY_RSA1);
364 bits = buffer_get_int(&e->request);
365 buffer_get_bignum(&e->request, key->rsa->e);
366 buffer_get_bignum(&e->request, key->rsa->n);
367
368 if (bits != key_size(key))
369 logit("Warning: identity keysize mismatch: actual %u, announced %u",
370 key_size(key), bits);
371 break;
372 case 2:
373 blob = buffer_get_string(&e->request, &blen);
374 key = key_from_blob(blob, blen);
375 xfree(blob);
376 break;
377 }
378 if (key != NULL) {
379 Identity *id = lookup_identity(key, version);
380 if (id != NULL) {
381 /*
382 * We have this key. Free the old key. Since we
383 * don't want to leave empty slots in the middle of
384 * the array, we actually free the key there and move
385 * all the entries between the empty slot and the end
386 * of the array.
387 */
388 Idtab *tab = idtab_lookup(version);
389 if (tab->nentries < 1)
390 fatal("process_remove_identity: "
391 "internal error: tab->nentries %d",
392 tab->nentries);
393 TAILQ_REMOVE(&tab->idlist, id, next);
394 free_identity(id);
395 tab->nentries--;
396 success = 1;
397 }
398 key_free(key);
399 }
400 buffer_put_int(&e->output, 1);
401 buffer_put_char(&e->output,
402 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
403 }
404
405 static void
406 process_remove_all_identities(SocketEntry *e, int version)
407 {
408 Idtab *tab = idtab_lookup(version);
409 Identity *id;
410
411 /* Loop over all identities and clear the keys. */
412 for (id = TAILQ_FIRST(&tab->idlist); id;
413 id = TAILQ_FIRST(&tab->idlist)) {
414 TAILQ_REMOVE(&tab->idlist, id, next);
415 free_identity(id);
416 }
417
418 /* Mark that there are no identities. */
419 tab->nentries = 0;
420
421 /* Send success. */
422 buffer_put_int(&e->output, 1);
423 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
424 }
425
426 /* removes expired keys and returns number of seconds until the next expiry */
427 static u_int
428 reaper(void)
429 {
430 u_int deadline = 0, now = time(NULL);
431 Identity *id, *nxt;
432 int version;
433 Idtab *tab;
434
435 for (version = 1; version < 3; version++) {
436 tab = idtab_lookup(version);
437 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
438 nxt = TAILQ_NEXT(id, next);
439 if (id->death == 0)
440 continue;
441 if (now >= id->death) {
442 debug("expiring key '%s'", id->comment);
443 TAILQ_REMOVE(&tab->idlist, id, next);
444 free_identity(id);
445 tab->nentries--;
446 } else
447 deadline = (deadline == 0) ? id->death :
448 MIN(deadline, id->death);
449 }
450 }
451 if (deadline == 0 || deadline <= now)
452 return 0;
453 else
454 return (deadline - now);
455 }
456
457 static void
458 process_add_identity(SocketEntry *e, int version)
459 {
460 Idtab *tab = idtab_lookup(version);
461 Identity *id;
462 int type, success = 0, death = 0, confirm = 0;
463 char *type_name, *comment;
464 Key *k = NULL;
465
466 switch (version) {
467 case 1:
468 k = key_new_private(KEY_RSA1);
469 (void) buffer_get_int(&e->request); /* ignored */
470 buffer_get_bignum(&e->request, k->rsa->n);
471 buffer_get_bignum(&e->request, k->rsa->e);
472 buffer_get_bignum(&e->request, k->rsa->d);
473 buffer_get_bignum(&e->request, k->rsa->iqmp);
474
475 /* SSH and SSL have p and q swapped */
476 buffer_get_bignum(&e->request, k->rsa->q); /* p */
477 buffer_get_bignum(&e->request, k->rsa->p); /* q */
478
479 /* Generate additional parameters */
480 rsa_generate_additional_parameters(k->rsa);
481 break;
482 case 2:
483 type_name = buffer_get_string(&e->request, NULL);
484 type = key_type_from_name(type_name);
485 xfree(type_name);
486 switch (type) {
487 case KEY_DSA:
488 k = key_new_private(type);
489 buffer_get_bignum2(&e->request, k->dsa->p);
490 buffer_get_bignum2(&e->request, k->dsa->q);
491 buffer_get_bignum2(&e->request, k->dsa->g);
492 buffer_get_bignum2(&e->request, k->dsa->pub_key);
493 buffer_get_bignum2(&e->request, k->dsa->priv_key);
494 break;
495 case KEY_RSA:
496 k = key_new_private(type);
497 buffer_get_bignum2(&e->request, k->rsa->n);
498 buffer_get_bignum2(&e->request, k->rsa->e);
499 buffer_get_bignum2(&e->request, k->rsa->d);
500 buffer_get_bignum2(&e->request, k->rsa->iqmp);
501 buffer_get_bignum2(&e->request, k->rsa->p);
502 buffer_get_bignum2(&e->request, k->rsa->q);
503
504 /* Generate additional parameters */
505 rsa_generate_additional_parameters(k->rsa);
506 break;
507 default:
508 buffer_clear(&e->request);
509 goto send;
510 }
511 break;
512 }
513 /* enable blinding */
514 switch (k->type) {
515 case KEY_RSA:
516 case KEY_RSA1:
517 if (RSA_blinding_on(k->rsa, NULL) != 1) {
518 error("process_add_identity: RSA_blinding_on failed");
519 key_free(k);
520 goto send;
521 }
522 break;
523 }
524 comment = buffer_get_string(&e->request, NULL);
525 if (k == NULL) {
526 xfree(comment);
527 goto send;
528 }
529 success = 1;
530 while (buffer_len(&e->request)) {
531 switch (buffer_get_char(&e->request)) {
532 case SSH_AGENT_CONSTRAIN_LIFETIME:
533 death = time(NULL) + buffer_get_int(&e->request);
534 break;
535 case SSH_AGENT_CONSTRAIN_CONFIRM:
536 confirm = 1;
537 break;
538 default:
539 break;
540 }
541 }
542 if (lifetime && !death)
543 death = time(NULL) + lifetime;
544 if ((id = lookup_identity(k, version)) == NULL) {
545 id = xmalloc(sizeof(Identity));
546 id->key = k;
547 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
548 /* Increment the number of identities. */
549 tab->nentries++;
550 } else {
551 key_free(k);
552 xfree(id->comment);
553 }
554 id->comment = comment;
555 id->death = death;
556 id->confirm = confirm;
557 send:
558 buffer_put_int(&e->output, 1);
559 buffer_put_char(&e->output,
560 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
561 }
562
563 /* XXX todo: encrypt sensitive data with passphrase */
564 static void
565 process_lock_agent(SocketEntry *e, int lock)
566 {
567 int success = 0;
568 char *passwd;
569
570 passwd = buffer_get_string(&e->request, NULL);
571 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
572 locked = 0;
573 memset(lock_passwd, 0, strlen(lock_passwd));
574 xfree(lock_passwd);
575 lock_passwd = NULL;
576 success = 1;
577 } else if (!locked && lock) {
578 locked = 1;
579 lock_passwd = xstrdup(passwd);
580 success = 1;
581 }
582 memset(passwd, 0, strlen(passwd));
583 xfree(passwd);
584
585 buffer_put_int(&e->output, 1);
586 buffer_put_char(&e->output,
587 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
588 }
589
590 static void
591 no_identities(SocketEntry *e, u_int type)
592 {
593 Buffer msg;
594
595 buffer_init(&msg);
596 buffer_put_char(&msg,
597 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
598 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
599 buffer_put_int(&msg, 0);
600 buffer_put_int(&e->output, buffer_len(&msg));
601 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
602 buffer_free(&msg);
603 }
604
605 #ifdef SMARTCARD
606 static void
607 process_add_smartcard_key (SocketEntry *e)
608 {
609 char *sc_reader_id = NULL, *pin;
610 int i, version, success = 0, death = 0, confirm = 0;
611 Key **keys, *k;
612 Identity *id;
613 Idtab *tab;
614
615 sc_reader_id = buffer_get_string(&e->request, NULL);
616 pin = buffer_get_string(&e->request, NULL);
617
618 while (buffer_len(&e->request)) {
619 switch (buffer_get_char(&e->request)) {
620 case SSH_AGENT_CONSTRAIN_LIFETIME:
621 death = time(NULL) + buffer_get_int(&e->request);
622 break;
623 case SSH_AGENT_CONSTRAIN_CONFIRM:
624 confirm = 1;
625 break;
626 default:
627 break;
628 }
629 }
630 if (lifetime && !death)
631 death = time(NULL) + lifetime;
632
633 keys = sc_get_keys(sc_reader_id, pin);
634 xfree(sc_reader_id);
635 xfree(pin);
636
637 if (keys == NULL || keys[0] == NULL) {
638 error("sc_get_keys failed");
639 goto send;
640 }
641 for (i = 0; keys[i] != NULL; i++) {
642 k = keys[i];
643 version = k->type == KEY_RSA1 ? 1 : 2;
644 tab = idtab_lookup(version);
645 if (lookup_identity(k, version) == NULL) {
646 id = xmalloc(sizeof(Identity));
647 id->key = k;
648 id->comment = sc_get_key_label(k);
649 id->death = death;
650 id->confirm = confirm;
651 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
652 tab->nentries++;
653 success = 1;
654 } else {
655 key_free(k);
656 }
657 keys[i] = NULL;
658 }
659 xfree(keys);
660 send:
661 buffer_put_int(&e->output, 1);
662 buffer_put_char(&e->output,
663 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
664 }
665
666 static void
667 process_remove_smartcard_key(SocketEntry *e)
668 {
669 char *sc_reader_id = NULL, *pin;
670 int i, version, success = 0;
671 Key **keys, *k = NULL;
672 Identity *id;
673 Idtab *tab;
674
675 sc_reader_id = buffer_get_string(&e->request, NULL);
676 pin = buffer_get_string(&e->request, NULL);
677 keys = sc_get_keys(sc_reader_id, pin);
678 xfree(sc_reader_id);
679 xfree(pin);
680
681 if (keys == NULL || keys[0] == NULL) {
682 error("sc_get_keys failed");
683 goto send;
684 }
685 for (i = 0; keys[i] != NULL; i++) {
686 k = keys[i];
687 version = k->type == KEY_RSA1 ? 1 : 2;
688 if ((id = lookup_identity(k, version)) != NULL) {
689 tab = idtab_lookup(version);
690 TAILQ_REMOVE(&tab->idlist, id, next);
691 tab->nentries--;
692 free_identity(id);
693 success = 1;
694 }
695 key_free(k);
696 keys[i] = NULL;
697 }
698 xfree(keys);
699 send:
700 buffer_put_int(&e->output, 1);
701 buffer_put_char(&e->output,
702 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
703 }
704 #endif /* SMARTCARD */
705
706 /* dispatch incoming messages */
707
708 static void
709 process_message(SocketEntry *e)
710 {
711 u_int msg_len, type;
712 u_char *cp;
713
714 if (buffer_len(&e->input) < 5)
715 return; /* Incomplete message. */
716 cp = buffer_ptr(&e->input);
717 msg_len = get_u32(cp);
718 if (msg_len > 256 * 1024) {
719 close_socket(e);
720 return;
721 }
722 if (buffer_len(&e->input) < msg_len + 4)
723 return;
724
725 /* move the current input to e->request */
726 buffer_consume(&e->input, 4);
727 buffer_clear(&e->request);
728 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
729 buffer_consume(&e->input, msg_len);
730 type = buffer_get_char(&e->request);
731
732 /* check wheter agent is locked */
733 if (locked && type != SSH_AGENTC_UNLOCK) {
734 buffer_clear(&e->request);
735 switch (type) {
736 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
737 case SSH2_AGENTC_REQUEST_IDENTITIES:
738 /* send empty lists */
739 no_identities(e, type);
740 break;
741 default:
742 /* send a fail message for all other request types */
743 buffer_put_int(&e->output, 1);
744 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
745 }
746 return;
747 }
748
749 debug("type %d", type);
750 switch (type) {
751 case SSH_AGENTC_LOCK:
752 case SSH_AGENTC_UNLOCK:
753 process_lock_agent(e, type == SSH_AGENTC_LOCK);
754 break;
755 /* ssh1 */
756 case SSH_AGENTC_RSA_CHALLENGE:
757 process_authentication_challenge1(e);
758 break;
759 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
760 process_request_identities(e, 1);
761 break;
762 case SSH_AGENTC_ADD_RSA_IDENTITY:
763 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
764 process_add_identity(e, 1);
765 break;
766 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
767 process_remove_identity(e, 1);
768 break;
769 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
770 process_remove_all_identities(e, 1);
771 break;
772 /* ssh2 */
773 case SSH2_AGENTC_SIGN_REQUEST:
774 process_sign_request2(e);
775 break;
776 case SSH2_AGENTC_REQUEST_IDENTITIES:
777 process_request_identities(e, 2);
778 break;
779 case SSH2_AGENTC_ADD_IDENTITY:
780 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
781 process_add_identity(e, 2);
782 break;
783 case SSH2_AGENTC_REMOVE_IDENTITY:
784 process_remove_identity(e, 2);
785 break;
786 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
787 process_remove_all_identities(e, 2);
788 break;
789 #ifdef SMARTCARD
790 case SSH_AGENTC_ADD_SMARTCARD_KEY:
791 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
792 process_add_smartcard_key(e);
793 break;
794 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
795 process_remove_smartcard_key(e);
796 break;
797 #endif /* SMARTCARD */
798 default:
799 /* Unknown message. Respond with failure. */
800 error("Unknown message %d", type);
801 buffer_clear(&e->request);
802 buffer_put_int(&e->output, 1);
803 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
804 break;
805 }
806 }
807
808 static void
809 new_socket(sock_type type, int fd)
810 {
811 u_int i, old_alloc, new_alloc;
812
813 set_nonblock(fd);
814
815 if (fd > max_fd)
816 max_fd = fd;
817
818 for (i = 0; i < sockets_alloc; i++)
819 if (sockets[i].type == AUTH_UNUSED) {
820 sockets[i].fd = fd;
821 buffer_init(&sockets[i].input);
822 buffer_init(&sockets[i].output);
823 buffer_init(&sockets[i].request);
824 sockets[i].type = type;
825 return;
826 }
827 old_alloc = sockets_alloc;
828 new_alloc = sockets_alloc + 10;
829 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
830 for (i = old_alloc; i < new_alloc; i++)
831 sockets[i].type = AUTH_UNUSED;
832 sockets_alloc = new_alloc;
833 sockets[old_alloc].fd = fd;
834 buffer_init(&sockets[old_alloc].input);
835 buffer_init(&sockets[old_alloc].output);
836 buffer_init(&sockets[old_alloc].request);
837 sockets[old_alloc].type = type;
838 }
839
840 static int
841 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
842 struct timeval **tvpp)
843 {
844 u_int i, sz, deadline;
845 int n = 0;
846 static struct timeval tv;
847
848 for (i = 0; i < sockets_alloc; i++) {
849 switch (sockets[i].type) {
850 case AUTH_SOCKET:
851 case AUTH_CONNECTION:
852 n = MAX(n, sockets[i].fd);
853 break;
854 case AUTH_UNUSED:
855 break;
856 default:
857 fatal("Unknown socket type %d", sockets[i].type);
858 break;
859 }
860 }
861
862 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
863 if (*fdrp == NULL || sz > *nallocp) {
864 if (*fdrp)
865 xfree(*fdrp);
866 if (*fdwp)
867 xfree(*fdwp);
868 *fdrp = xmalloc(sz);
869 *fdwp = xmalloc(sz);
870 *nallocp = sz;
871 }
872 if (n < *fdl)
873 debug("XXX shrink: %d < %d", n, *fdl);
874 *fdl = n;
875 memset(*fdrp, 0, sz);
876 memset(*fdwp, 0, sz);
877
878 for (i = 0; i < sockets_alloc; i++) {
879 switch (sockets[i].type) {
880 case AUTH_SOCKET:
881 case AUTH_CONNECTION:
882 FD_SET(sockets[i].fd, *fdrp);
883 if (buffer_len(&sockets[i].output) > 0)
884 FD_SET(sockets[i].fd, *fdwp);
885 break;
886 default:
887 break;
888 }
889 }
890 deadline = reaper();
891 if (parent_alive_interval != 0)
892 deadline = (deadline == 0) ? parent_alive_interval :
893 MIN(deadline, parent_alive_interval);
894 if (deadline == 0) {
895 *tvpp = NULL;
896 } else {
897 tv.tv_sec = deadline;
898 tv.tv_usec = 0;
899 *tvpp = &tv;
900 }
901 return (1);
902 }
903
904 static void
905 after_select(fd_set *readset, fd_set *writeset)
906 {
907 struct sockaddr_un sunaddr;
908 socklen_t slen;
909 char buf[1024];
910 int len, sock;
911 u_int i;
912 uid_t euid;
913 gid_t egid;
914
915 for (i = 0; i < sockets_alloc; i++)
916 switch (sockets[i].type) {
917 case AUTH_UNUSED:
918 break;
919 case AUTH_SOCKET:
920 if (FD_ISSET(sockets[i].fd, readset)) {
921 slen = sizeof(sunaddr);
922 sock = accept(sockets[i].fd,
923 (struct sockaddr *)&sunaddr, &slen);
924 if (sock < 0) {
925 error("accept from AUTH_SOCKET: %s",
926 strerror(errno));
927 break;
928 }
929 if (getpeereid(sock, &euid, &egid) < 0) {
930 error("getpeereid %d failed: %s",
931 sock, strerror(errno));
932 close(sock);
933 break;
934 }
935 if ((euid != 0) && (getuid() != euid)) {
936 error("uid mismatch: "
937 "peer euid %u != uid %u",
938 (u_int) euid, (u_int) getuid());
939 close(sock);
940 break;
941 }
942 new_socket(AUTH_CONNECTION, sock);
943 }
944 break;
945 case AUTH_CONNECTION:
946 if (buffer_len(&sockets[i].output) > 0 &&
947 FD_ISSET(sockets[i].fd, writeset)) {
948 do {
949 len = write(sockets[i].fd,
950 buffer_ptr(&sockets[i].output),
951 buffer_len(&sockets[i].output));
952 if (len == -1 && (errno == EAGAIN ||
953 errno == EINTR))
954 continue;
955 break;
956 } while (1);
957 if (len <= 0) {
958 close_socket(&sockets[i]);
959 break;
960 }
961 buffer_consume(&sockets[i].output, len);
962 }
963 if (FD_ISSET(sockets[i].fd, readset)) {
964 do {
965 len = read(sockets[i].fd, buf, sizeof(buf));
966 if (len == -1 && (errno == EAGAIN ||
967 errno == EINTR))
968 continue;
969 break;
970 } while (1);
971 if (len <= 0) {
972 close_socket(&sockets[i]);
973 break;
974 }
975 buffer_append(&sockets[i].input, buf, len);
976 process_message(&sockets[i]);
977 }
978 break;
979 default:
980 fatal("Unknown type %d", sockets[i].type);
981 }
982 }
983
984 static void
985 cleanup_socket(void)
986 {
987 if (socket_name[0])
988 unlink(socket_name);
989 if (socket_dir[0])
990 rmdir(socket_dir);
991 }
992
993 void
994 cleanup_exit(int i)
995 {
996 cleanup_socket();
997 _exit(i);
998 }
999
1000 /*ARGSUSED*/
1001 static void
1002 cleanup_handler(int sig)
1003 {
1004 cleanup_socket();
1005 _exit(2);
1006 }
1007
1008 static void
1009 check_parent_exists(void)
1010 {
1011 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1012 /* printf("Parent has died - Authentication agent exiting.\n"); */
1013 cleanup_socket();
1014 _exit(2);
1015 }
1016 }
1017
1018 static void
1019 usage(void)
1020 {
1021 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1022 __progname);
1023 fprintf(stderr, "Options:\n");
1024 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1025 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1026 fprintf(stderr, " -k Kill the current agent.\n");
1027 fprintf(stderr, " -d Debug mode.\n");
1028 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1029 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1030 exit(1);
1031 }
1032
1033 int
1034 main(int ac, char **av)
1035 {
1036 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1037 int sock, fd, ch, result, saved_errno;
1038 u_int nalloc;
1039 char *shell, *format, *pidstr, *agentsocket = NULL;
1040 fd_set *readsetp = NULL, *writesetp = NULL;
1041 struct sockaddr_un sunaddr;
1042 #ifdef HAVE_SETRLIMIT
1043 struct rlimit rlim;
1044 #endif
1045 int prev_mask;
1046 extern int optind;
1047 extern char *optarg;
1048 pid_t pid;
1049 char pidstrbuf[1 + 3 * sizeof pid];
1050 struct timeval *tvp = NULL;
1051
1052 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1053 sanitise_stdfd();
1054
1055 /* drop */
1056 setegid(getgid());
1057 setgid(getgid());
1058 setuid(geteuid());
1059
1060 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1061 /* Disable ptrace on Linux without sgid bit */
1062 prctl(PR_SET_DUMPABLE, 0);
1063 #endif
1064
1065 SSLeay_add_all_algorithms();
1066
1067 __progname = ssh_get_progname(av[0]);
1068 init_rng();
1069 seed_rng();
1070
1071 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1072 switch (ch) {
1073 case 'c':
1074 if (s_flag)
1075 usage();
1076 c_flag++;
1077 break;
1078 case 'k':
1079 k_flag++;
1080 break;
1081 case 's':
1082 if (c_flag)
1083 usage();
1084 s_flag++;
1085 break;
1086 case 'd':
1087 if (d_flag)
1088 usage();
1089 d_flag++;
1090 break;
1091 case 'a':
1092 agentsocket = optarg;
1093 break;
1094 case 't':
1095 if ((lifetime = convtime(optarg)) == -1) {
1096 fprintf(stderr, "Invalid lifetime\n");
1097 usage();
1098 }
1099 break;
1100 default:
1101 usage();
1102 }
1103 }
1104 ac -= optind;
1105 av += optind;
1106
1107 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1108 usage();
1109
1110 if (ac == 0 && !c_flag && !s_flag) {
1111 shell = getenv("SHELL");
1112 if (shell != NULL &&
1113 strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1114 c_flag = 1;
1115 }
1116 if (k_flag) {
1117 const char *errstr = NULL;
1118
1119 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1120 if (pidstr == NULL) {
1121 fprintf(stderr, "%s not set, cannot kill agent\n",
1122 SSH_AGENTPID_ENV_NAME);
1123 exit(1);
1124 }
1125 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1126 if (errstr) {
1127 fprintf(stderr,
1128 "%s=\"%s\", which is not a good PID: %s\n",
1129 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1130 exit(1);
1131 }
1132 if (kill(pid, SIGTERM) == -1) {
1133 perror("kill");
1134 exit(1);
1135 }
1136 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1137 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1138 printf(format, SSH_AGENTPID_ENV_NAME);
1139 printf("echo Agent pid %ld killed;\n", (long)pid);
1140 exit(0);
1141 }
1142 parent_pid = getpid();
1143
1144 if (agentsocket == NULL) {
1145 /* Create private directory for agent socket */
1146 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1147 if (mkdtemp(socket_dir) == NULL) {
1148 perror("mkdtemp: private socket dir");
1149 exit(1);
1150 }
1151 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1152 (long)parent_pid);
1153 } else {
1154 /* Try to use specified agent socket */
1155 socket_dir[0] = '\0';
1156 strlcpy(socket_name, agentsocket, sizeof socket_name);
1157 }
1158
1159 /*
1160 * Create socket early so it will exist before command gets run from
1161 * the parent.
1162 */
1163 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1164 if (sock < 0) {
1165 perror("socket");
1166 *socket_name = '\0'; /* Don't unlink any existing file */
1167 cleanup_exit(1);
1168 }
1169 memset(&sunaddr, 0, sizeof(sunaddr));
1170 sunaddr.sun_family = AF_UNIX;
1171 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1172 prev_mask = umask(0177);
1173 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1174 perror("bind");
1175 *socket_name = '\0'; /* Don't unlink any existing file */
1176 umask(prev_mask);
1177 cleanup_exit(1);
1178 }
1179 umask(prev_mask);
1180 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1181 perror("listen");
1182 cleanup_exit(1);
1183 }
1184
1185 /*
1186 * Fork, and have the parent execute the command, if any, or present
1187 * the socket data. The child continues as the authentication agent.
1188 */
1189 if (d_flag) {
1190 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1191 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1192 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1193 SSH_AUTHSOCKET_ENV_NAME);
1194 printf("echo Agent pid %ld;\n", (long)parent_pid);
1195 goto skip;
1196 }
1197 pid = fork();
1198 if (pid == -1) {
1199 perror("fork");
1200 cleanup_exit(1);
1201 }
1202 if (pid != 0) { /* Parent - execute the given command. */
1203 close(sock);
1204 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1205 if (ac == 0) {
1206 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1207 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1208 SSH_AUTHSOCKET_ENV_NAME);
1209 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1210 SSH_AGENTPID_ENV_NAME);
1211 printf("echo Agent pid %ld;\n", (long)pid);
1212 exit(0);
1213 }
1214 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1215 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1216 perror("setenv");
1217 exit(1);
1218 }
1219 execvp(av[0], av);
1220 perror(av[0]);
1221 exit(1);
1222 }
1223 /* child */
1224 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1225
1226 if (setsid() == -1) {
1227 error("setsid: %s", strerror(errno));
1228 cleanup_exit(1);
1229 }
1230
1231 (void)chdir("/");
1232 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1233 /* XXX might close listen socket */
1234 (void)dup2(fd, STDIN_FILENO);
1235 (void)dup2(fd, STDOUT_FILENO);
1236 (void)dup2(fd, STDERR_FILENO);
1237 if (fd > 2)
1238 close(fd);
1239 }
1240
1241 #ifdef HAVE_SETRLIMIT
1242 /* deny core dumps, since memory contains unencrypted private keys */
1243 rlim.rlim_cur = rlim.rlim_max = 0;
1244 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1245 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1246 cleanup_exit(1);
1247 }
1248 #endif
1249
1250 skip:
1251 new_socket(AUTH_SOCKET, sock);
1252 if (ac > 0)
1253 parent_alive_interval = 10;
1254 idtab_init();
1255 if (!d_flag)
1256 signal(SIGINT, SIG_IGN);
1257 signal(SIGPIPE, SIG_IGN);
1258 signal(SIGHUP, cleanup_handler);
1259 signal(SIGTERM, cleanup_handler);
1260 nalloc = 0;
1261
1262 while (1) {
1263 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1264 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1265 saved_errno = errno;
1266 if (parent_alive_interval != 0)
1267 check_parent_exists();
1268 (void) reaper(); /* remove expired keys */
1269 if (result < 0) {
1270 if (saved_errno == EINTR)
1271 continue;
1272 fatal("select: %s", strerror(saved_errno));
1273 } else if (result > 0)
1274 after_select(readsetp, writesetp);
1275 }
1276 /* NOTREACHED */
1277 }
DragonFly BSD